Abstract: The purpose of this study was to test femur strength and the ability to prevent fracture displacement of two minimal invasive Elastomer femoroplasty techniques.
Abstract: OBJECTIVE: To validate a newly developed quantification method that automatically detects and quantifies the joint space width (JSW) in hand radiographs. Repeatability, accuracy and sensitivity to changes in JSW were determined. The influence of joint location and joint shape on the measurements was tested. METHODS: A mechanical micrometer set-up was developed to define and adjust the true JSW in an acrylic phantom joint and in human cadaver-derived phalangeal joints. Radiographic measurements of the JSW were compared to the true JSW. Repeatability, systematic error (accuracy) and sensitivity (defined as the smallest detectable difference (SDD)) were determined. The influence of joint position on the JSW measurement was assessed by varying the location of the acrylic phantom on the X-ray detector with respect to the X-ray beam and the influence of joint shape was determined by using morphologically different human cadaver joints. RESULTS: The mean systematic error was 0.052 mm in the phantom joint and 0.210 mm in the cadaver experiment. In the phantom experiments, the repeatability was high (SDD = 0.028 mm), but differed slightly between joint locations (p = 0.046), and a change in JSW of 0.037 mm could be detected. Dependent of the joint shape in the cadaver hand, a change in JSW between 0.018 and 0.047 mm could be detected. CONCLUSIONS: The automatic quantification method is sensitive to small changes in JSW. Considering the published data of JSW decline in the normal and osteoarthritic population, the first signs of OA progression with this method can be detected within 1 or 2 years.
Abstract: Aim of our study was to compare functional ability and physical activity in children and young adults who underwent surgery for a malignant bone tumor that was located around the knee.
Abstract: Obesity is a risk factor for the development of osteoarthritis (OA) in hands and knees. Adipose tissue can secrete different adipokines with powerful immunomodulatory effects. The infrapatellar fat pad (IFP) is an intra-articular organ in the vicinity of the synovium and cartilage. It is hypothesised that IFP-derived soluble factors could contribute to pathological processes in the knee joint. A study was therefore undertaken to compare the release of inflammatory mediators in the IFP and subcutaneous adipose tissue (ScAT) and to characterise the adipocytes and immune cell infiltrate in these tissues.
Abstract: BackgroundA number of excellent results with the cementless titanium femoral component of the Mallory Head Total Hip Replacement have been published. Unfortunately, these excellent results have been counteracted by the poor performance of the cementless titanium acetabular components. In 1994, the HexLoc acetabular component was replaced with a second-generation design, the RingLoc. We hypothesized that the new generation would have improved the results. Methods We retrospectively studied 111 consecutive patients (150 hips) younger than 55 years. Median follow-up time was 14 (6?18) years for the HexLoc and 10 (1?14) years for the RingLoc. 7 patients were lost to follow-up and 7 patients died. The 10-year survival rate, radiographic liner wear, and radiographic signs of prosthesis failure were compared between the 2 acetabular components. Results The Kaplan-Meier survival estimate with revision for any reason as the endpoint showed a 10-year survival of 89% (95% CI: 81?97) for the HexLoc and 92% (CI: 85?98) for the RingLoc. The mean annual wear rate for the HexLoc was 0.16 (SD 0.16) mm and it was 0.15 (0.1) mm for the RingLoc (p = 0.3). The radiographic signs of failure were equally distributed between the 2 groups. Interpretation Compared to the HexLoc type, the RingLoc system did not improve the mean percentage survival at 10 years; nor did it reduce the liner wear. Despite correction of the known design flaws in the HexLoc design, the RingLoc system did not show a clinically relevant improvement compared to its predecessor.
Abstract: Rotation of the femoral component in total knee arthroplasty (TKA) is of high importance in respect of the balancing of the knee and the patellofemoral joint. Though it is shown that computer assisted surgery (CAOS) improves the anteroposterior (AP) alignment in TKA, it is still unknown whether navigation helps in finding the accurate rotation or even improving rotation. Therefore the aim of our study was to evaluate the postoperative femoral component rotation on computed tomography (CT) with the intraoperative data of the navigation system. In 20 navigated TKAs the difference between the intraoperative stored rotation data of the femoral component and the postoperative rotation on CT was measured using the condylar twist angle (CTA). This is the angle between the epicondylar axis and the posterior condylar axis. Statistical analysis consisted of the intraclass correlation coefficient (ICC) and Bland-Altman plot. The mean intraoperative rotation CTA based on CAOS was 3.5° (range 2.4-8.6°). The postoperative CT scan showed a mean CTA of 4.0° (1.7-7.2). The ICC between the two observers was 0.81, and within observers this was 0.84 and 0.82, respectively. However, the ICC of the CAOS CTA versus the postoperative CT CTA was only 0.38. Though CAOS is being used for optimising the position of a TKA, this study shows that the (virtual) individual rotational position of the femoral component using a CAOS system is significantly different from the position on a postoperative CT scan.
Abstract: Relative movement of skin markers to underlying bone limits a valid interpretation of axial femorotibial rotation in noninvasive optoelectronic gait analysis. A distal femoral clamp is a practical solution for thigh marker placement, however, existing devices are still susceptible to measurement errors at increased angles of knee flexion. We developed the Femoral Epicondylar Frame (FEF), which should result in less femoral rotational measurement error due to its anatomic fitting and controlled pressure adjustment. Seven subjects with a total knee replacement in situ, mean age 71 years, mean body mass index 28, were equipped with the frame mounted with a set of tantalum markers. Fluoroscopic data was collected during a step-up motion. A three-dimensional model fitting technique was used to compare the in vivo position and orientation of the frame and the femoral prosthesis component of the prosthesis. The frame rotational measurement error appeared to be linearly dependent on the knee flexion angle. When considering knee flexion angles lower than 40° of flexion, the highest measurement error was 3.3° on average, with an absolute extreme of 6.2°. It is concluded that the accuracy of the FEF is sufficient to evaluate axial knee rotation with optoelectronic gait analysis at group level in clinical studies.
Abstract: The aim of this study was the evaluation of contralateral hip fractures after a previous hip fracture. For this retrospective analysis patients were selected from the database of the LUMC, a teaching hospital in the south-west of the Netherlands. We analyzed all patients with a second fracture of a hip between 1992 and 2007. The exclusion criteria were high impact trauma and patients with diseases or medication known to have a negative effect on bone metabolism. A total of 1,604 hip fractures were identified. The possible predictive factors for the second fracture and descriptive statistics related to surgery (Hb and HT before and after the operation, total amount of intra- and postoperative blood loss, type of osteosynthesis, complications, time of death after the last fracture, time between arrival in the hospital and operation and hospital stay for both fractures) were recorded. A total of 32 second hip fractures were identified (2%) at a mean of 27.5 (SD 28.9) months after the initial hip fracture. The mean age at the first fracture was 77.2 years (SD 11.7), and 27 of 32 patients were female. Of these 32 patients (64 bilateral hip fractures), 32 fractures were intracapsular (1 femoral neck, 31 subcapital) and 32 were extracapsular fractures (6 subtrochanteric, 26 transtrochanteric). Although 24 of the 32 patients had identical first and second hip fractures, only eight out of 32 hips were treated with the same implants. There was a significant difference in Singh index between both hips at the time of the first fracture. There was also a significant difference in Singh index between the hip which was not fractured compared with its subsequent index when it was broken. All other studied patient and fracture characteristics were not significantly different. In this population the percentage of second hip fractures was relatively low compared to other studies. The choice of implants in this study shows that implants were chosen randomly. Because there is a significant difference in the Singh index during first and second hip fracture, osteoporosis medication might help reduce the incidence of second hip fractures.
Abstract: PURPOSE: The aim of this study was to compare a broad range of total knee prostheses with different design parameters to determine whether in vivo kinematics was consistently related to design. The hypothesis was that there are no clear recognizable differences in in vivo kinematics between different design parameters or prostheses. METHODS: At two sites, data were collected by a single observer on 52 knees (49 subjects with rheumatoid arthritis or osteoarthritis). Six different total knee prostheses were used: multi-radius, single-radius, fixed-bearing, mobile-bearing, posterior-stabilized, cruciate retaining and cruciate sacrificing. Knee kinematics was recorded using fluoroscopy as the patients performed a step-up motion. RESULTS: There was a significant effect of prosthetic design on all outcome parameters; however, post hoc tests showed that the NexGen group was responsible for 80% of the significant values. The range of knee flexion was much smaller in this group, resulting in smaller anterior-posterior translations and rotations. CONCLUSION: Despite kinematics being generally consistent with the kinematics intended by their design, there were no clear recognizable differences in in vivo kinematics between different design parameters or prostheses. Hence, the differences in design parameters or prostheses are not distinct enough to have an effect on clinical outcome of patients. LEVEL OF EVIDENCE: Therapeutic study, Level III.
Abstract: OBJECTIVE: Computed tomography is the modality of choice for measuring osteolysis but suffers from metal-induced artefacts obscuring periprosthetic tissues. Previous papers on metal artefact reduction (MAR) show qualitative improvements, but their algorithms have not found acceptance for clinical applications. We investigated to what extent metal artefacts interfere with the segmentation of lesions adjacent to a metal femoral implant and whether metal artefact reduction improves the manual segmentation of such lesions. MATERIALS AND METHODS: We manually created 27 periprosthetic lesions in 10 human cadaver femora. We filled the lesions with a fibrotic interface tissue substitute. Each femur was fitted with a polished tapered cobalt-chrome prosthesis and imaged twice-once with the metal, and once with a substitute resin prosthesis inserted. Metal-affected CTs were processed using standard back-projection as well as projection interpolation (PI) MAR. Two experienced users segmented all lesions and compared segmentation accuracy. RESULTS: We achieved accurate delineation of periprosthetic lesions in the metal-free images. The presence of a metal implant led us to underestimate lesion volume and introduced geometrical errors in segmentation boundaries. Although PI MAR reduced streak artefacts, it led to greater underestimation of lesion volume and greater geometrical errors than without its application. CONCLUSION: CT metal artefacts impair image segmentation. PI MAR can improve subjective image appearance but causes loss of detail and lower image contrast adjacent to prostheses. Our experiments showed that PI MAR is counterproductive for manual segmentation of periprosthetic lesions and should be used with care.
Abstract: In the light of both the importance and large numbers of case series and cohort studies (observational studies) in orthopaedic literature, it is remarkable that there is currently no validated measurement tool to appraise their quality. A Delphi approach was used to develop a checklist for reporting quality, methodological quality and generalizability of case series and cohorts in total hip and total knee arthroplasty with a focus on aseptic loosening.
Abstract: PURPOSE: To systematically review published studies comparing Quality of Life (QoL), functional ability and/or physical activity between different surgical interventions due to a malignant bone tumour of the leg. METHODS: A systematic literature search, covering the years 2000-2010 was performed using the PubMed, Embase, Web of science and Cochrane databases. Studies were included if they described and statistically compared QoL, functional ability and/or physical activity of at least two surgical interventions for lower extremity bone cancer. In addition, the methodological quality of the selected studies was evaluated by using a 24-point scale. Where appropriate, a qualitative analysis or meta-analysis was performed. RESULTS: The search strategy resulted in a list of 246 citations. Based on titles and abstracts 50 full-text articles were selected, of which 13 articles describing 12 studies, were finally included. Overall, the methodological quality of the studies was moderate. Studies were heterogeneous with respect to their categorisation of surgical interventions, average age of patients and average duration of follow-up. Overall, results regarding differences between ablative and limb-sparing surgery varied largely. Meta-analysis was considered to be not appropriate due to clinical heterogeneity, methodological differences and flaws. CONCLUSION: Twelve studies comparing the outcomes of QoL, functional ability and physical activity between limb-sparing and ablative surgery groups were identified, with an overall moderate methodological quality. Their largely varying outcomes suggest that no general conclusions on the advantage of either limb-sparing or ablative surgery in patients with malignant bone tumours of the lower extremity can be drawn.
Abstract: BACKGROUND: The mobile-bearing variant of a single-radius design is assumed to provide more freedom of motion compared to the fixed-bearing variant because the insert does not restrict the natural movements of the femoral component. This would reduce the contact stresses and wear which in turn may have a positive effect on the fixation of the prosthesis to the bone and thereby decreases the risk for loosening. The aim of this study was to evaluate early migration of the tibial component and kinematics of a mobile-bearing and fixed-bearing total knee prosthesis of the same single-radius design. METHODS: Twenty Triathlon single-radius posterior-stabilized knee prostheses were implanted (9 mobile-bearing and 11 fixed-bearing). Fluoroscopy and roentgen stereophotogrammetric analysis (RSA) were performed 6 and 12months post-operatively. FINDINGS: The 1year post-operative RSA results showed considerable early migrations in 3 out of 9 mobile-bearing patients and 1 out of 11 fixed-bearing patients. The range of knee flexion was the same for the mobile-bearing and fixed-bearing group. The mobile insert was following the femoral component during motion. INTERPRETATION: Despite the mobile insert following the femoral component during motion, and therefore performing as intended, no kinematic advantages of the mobile-bearing total knee prosthesis were seen. The fixed-bearing knee performed as good as the mobile-bearing knee and maybe even slightly better based on less irregular kinematics and less early migrations.
Abstract: With fluoroscopic analysis of knee implant kinematics the implant contour must be detected in each image frame, followed by estimation of the implant pose. With a large number of possibly low-quality images, the contour detection is a time-consuming bottleneck. The present paper proposes an automated contour detection method, which is integrated in the pose estimation. In a phantom experiment the automated method was compared with a standard method, which uses manual selection of correct contour parts. Both methods demonstrated comparable precision, with a minor difference in the Y-position (0.08 mm versus 0.06 mm). The precision of each method was so small (below 0.2 mm and 0.3 degrees) that both are sufficiently accurate for clinical research purposes. The efficiency of both methods was assessed on six clinical datasets. With the automated method the observer spent 1.5 min per image, significantly less than 3.9 min with the standard method. A Bland-Altman analysis between the methods demonstrated no discernible trends in the relative femoral poses. The threefold increase in efficiency demonstrates that a pose estimation approach with integrated contour detection is more intuitive than a standard method. It eliminates most of the manual work in fluoroscopic analysis, with sufficient precision for clinical research purposes.
Abstract: To investigate the validity of joint space width (JSW) measurements in millimeters (mm) in hand osteoarthritis (OA) patients by comparison to controls, grading of joint space narrowing (JSN), and clinical features.
Abstract: Accurate in vivo measurements methods of wear in total knee arthroplasty are required for a timely detection of excessive wear and to assess new implant designs. Component separation measurements based on model-based Roentgen stereophotogrammetric analysis (RSA), in which 3-dimensional reconstruction methods are used, have shown promising results, yet the robustness of these measurements is unknown. In this study, the accuracy and robustness of this measurement for clinical usage was assessed. The validation experiments were conducted in an RSA setup with a phantom setup of a knee in a vertical orientation. 72 RSA images were created using different variables for knee orientations, two prosthesis types (fixed-bearing Duracon knee and fixed-bearing Triathlon knee) and accuracies of the reconstruction models. The measurement error was determined for absolute and relative measurements and the effect of knee positioning and true seperation distance was determined. The measurement method overestimated the separation distance with 0.1mm on average. The precision of the method was 0.10mm (2*SD) for the Duracon prosthesis and 0.20mm for the Triathlon prosthesis. A slight difference in error was found between the measurements with 0° and 10° anterior tilt. (difference=0.08mm, p=0.04). The accuracy of 0.1mm and precision of 0.2mm can be achieved for linear wear measurements based on model-based RSA, which is more than adequate for clinical applications. The measurement is robust in clinical settings. Although anterior tilt seems to influence the measurement, the size of this influence is low and clinically irrelevant.
Abstract: Delirium in patients with hip fractures lead to higher morbidity and mortality. Prevention in high-risk patients by prescribing low dose haloperidol is currently under investigation.
Abstract: Aseptic loosening is the major failure mode for hip prostheses. Currently, loosened prostheses are revised during open surgery. Because of a high complication rate, this demanding procedure cannot be performed in patients with a poor general health. We are developing an alternative minimally invasive refixation procedure that leaves the prostheses in place, but relies on removing the interface membrane and replacing it with bone cement. The aim of this study was to evaluate two interface tissue removal techniques - Ho:YAG laser and coblation - based on two criteria: thermal damage and the ablation rate. In vitro a loosened hip prosthesis was simulated by implanting a prosthesis in each of 10 cadaver femora. Artificially created peri-prosthetic lesions were filled with chicken liver as an interface tissue substitute. We measured temperatures in vitro at different radial distances from the site of removal. Temperatures during removal were recorded both inside the interface tissue and in the surrounding bone. This study demonstrated that temperatures generated in the bone do not result in thermal damage (increasing less than 10°C relative to body temperature). Temperatures inside the interface tissue are sufficiently high to destroy the interface tissue (T>50°C, duration>1min). Using laser instead of coblation for the removal of interface tissue resulted in higher temperatures - thus a faster removal of interface tissue. This is in accordance with the ablation rate test. Ho:YAG laser is advantageous compared to coblation. We consider Ho:YAG laser a promising tool for interface tissue removal.
Abstract: PURPOSE: There is renewed interest in the all-polyethylene tibial component in total knee arthroplasty (TKA). Long-term results of this prosthesis in rheumatoid arthritis (RA) patients, however, are limited. Therefore, we studied 104 primary cemented all-polyethylene tibial TKA in 80 consecutive RA patients for up to 25 years to determine the long-term survival of all-polyethylene tibial components in patients suffering from end stage RA. METHODS: We estimated revision rates according the revision rate per 100 observed component years used in national joint registries. Kaplan-Meier was used to estimate survival curves. RESULTS: During the 25-year follow-up, three revisions for tibial component loosening were performed. The mean revision rate of all-polyethylene tibial components with revision for aseptic loosening as the endpoint was 0.09 per 100 observed component years. This corresponds to a revision rate of 0.9% after ten years and 2.25% after 25 years. Survivorship according to Kaplan-Meier was 100% at ten years and 87.5% at 25 years [95% confidence interval (CI) 64.6-100)]. CONCLUSION: This study shows good long-term results of all-polyethylene tibial TKA in patients with RA. RA patients with multiple-joint inflammation may be less physically active than osteoarthritis patients, resulting in a lower demand on the prosthesis, and these patients may, indeed, be good candidates for all-polyethylene tibial TKA. Our results suggest that all-polyethylene tibial TKA could be a successful and cost-saving treatment for end-stage knee arthritis in RA patients.
Abstract: In massive rotator cuff tears a teres major (TMj) tendon transfer to the insertion of the supraspinatus (SSp) reverses its adduction moment arm into abduction which is supposed to be an adequate salvage procedure. Analysis of muscle function to find biomechanical ground of such success is scarce.
Abstract: Medial opening wedge high tibial osteotmy (HTO) is often used to treat varus gonarthrosis in young, active, highly demanding patients, although it has many pitfalls, which were evaluated in a consecutive cohort of patients. A retrospective analysis of a consecutive series of 45 patients with 49 medial opening HTO for varus gonarthrosis using a spacer plate (Puddu I, Arthrex, USA) were included. A Chi square test was used to study the effect between the wedge size and complications. Complications occurred in 22 knees (45%). There was no significant difference between groups for individual complications; however, when combined, there were significantly more complications in the >10 mm wedge group (Chi square p = 0.05). The overall complication rate in this series was 45%. The majority were related to intrinsic instability at the osteotomy site (24%) and surgical technique (20%). The evaluated spacer provided inadequate stability.
Abstract: The use of Souter-Strathclyde total elbow prostheses is a well-studied replacement therapy for reconstruction of the elbow, but loosening of the humeral component is still of concern at long-term follow-up. In this study we looked at the effect of humeral component size and bone mineral density with respect to the bone size, torsional stiffness and torque to failure in cadaveric bones. Fourteen cadaveric humeri were available for testing purposes and four different humeral component size categories were used. First, we calculated the bone quality using dual-energy X-ray absorptiometry (DEXA). The torsional stiffness of the prosthetic humeri was measured during two mechanical tests: Firstly, the applied torque was recorded during a torsion fatigue test. The change of torsional stiffness between the tenth and last cycle was calculated. Secondly, a simple torsion test was performed and the torque to failure was recorded. No significant differences in outcome were seen between sizes of humeral components, even after correction for the bone size. Torsional stiffness and torque to failure were significantly correlated with bone mineral density and not with component size. In conclusion, bone quality seems to be a major eminent factor in the fixation of the humeral component in elbow replacement surgery.
Abstract: To define localized development of knee osteoarthritis (OA) that arises from anterior cruciate ligament (ACL) and meniscal injuries identified at magnetic resonance (MR) imaging performed a decade ago and the subsequent management of those findings in patients with subacute knee symptoms.
Abstract: Mechanical loosening which begins with early-onset migration of the prosthesis is the major reason for failure of the Souter-Strathclyde elbow replacement. In a prospective study of 18 Souter-Strathclyde replacements we evaluated the patterns of migration using roentgen stereophotogrammetric analysis. We had previously reported the short-term results after a follow-up of two years which we have now extended to a mean follow-up of 8.2 years (1 to 11.3). Migration was assessed along the co-ordinal axes and overall micromovement was expressed as the maximum total point movement. The alignment of the prosthesis and the presence of radiolucent lines were examined on conventional standardised radiographs. All the humeral components showed increased and variable patterns of migration at the extended follow-up and four humeral components were revised. The maximum total point movement at two years in the revised prostheses was 1.8 mm (sd 1.0) and in the non-revised 0.7 mm (sd 0.5, p = 0.01). Most humeral components migrated into external rotation resulting in an anterior and varus tilt. The ulnar components remained stable.
Abstract:  To identify hand function problems and the reasons for choosing a specific finger splint in patients with rheumatoid arthritis (RA) and swan neck deformities.
Abstract: In patients with rotator cuff tears lost elevation moments are compensated for by increased deltoid activation. Concomitant proximal directed destabilizing forces at the glenohumeral joint are suggested to be compensated for by 'out-of-phase' adductor activation, preserving glenohumeral stability. Aim of this study was to demonstrate causality between moment compensating deltoid activation and stability compensating 'out-of-phase' adductor muscle activation. A differential arm loading with the same magnitude of forces applied at small and large moment arms relative to the glenohumeral joint was employed to excite deltoid activation, without externally affecting the force balance. Musculoskeletal modeling was applied to analyze the protocol in terms of muscle forces and glenohumeral (in)stability. The protocol was applied experimentally using electromyography (EMG) to assess muscle activation of healthy controls and cuff tear patients. Both modeling and experiments demonstrated increased deltoid activation with increased moment loading, which was higher in patients compared to controls. Model simulation of cuff tears demonstrated glenohumeral instability and related 'out-of-phase' adductor muscle activation which was also found experimentally in patients when compared to controls. Through differential moment loading, the assumed causal relation between increased deltoid activation and compensatory adductor muscle activation in cuff tear patients could be demonstrated. 'Out-of-phase' adductor activation in patients was attributed to glenohumeral instability. The moment loading protocol discerned patients with cuff tears from controls based on muscle activation.
Abstract: Internal rotation contracture of the shoulder is common in children with neonatal brachial plexus palsy. A long-standing contracture may cause osseous deformities in the developing shoulder. The purpose of the study was to evaluate the relationship between osseous deformities of the glenohumeral joint and structural differences due to muscle denervation in the rotator cuff muscles.
Abstract: Prevention of hip fracture surgery in the elderly imposes great benefit for patient care as well as for society. The incidence of contra-lateral, second hip fractures after hip fracture surgery is as high as 20%. Augmentation of the contra-lateral proximal femur with silicone femoroplasty during hip fracture surgery of the ipsilateral hip could be a new preventive strategy. This study compared the degree of dislocation after a controlled induced fracture between treated and control cadaver femora.
Abstract: To describe the osteoarthritis study population of CHECK (Cohort Hip and Cohort Knee) in comparison with relevant selections of the study population of the Osteoarthritis Initiative (OAI) based on clinical status and radiographic parameters.
Abstract: In a previous fluoroscopy study the motion of a mobile bearing total knee prosthesis was evaluated. That study showed that the axial rotation of the insert was limited. Three possible explanations are given for the limited rotation: low conformity between the femoral component and insert, the fixed anterior position of the insert-tibia pivot point leading to impingement and fibrous tissue formation. While the effect of the conformity on the axial rotation will not change over time, the effect of impingement and fibrous tissue is likely to increase, and thereby further decreasing the axial rotation.
Abstract: To compare the effectiveness and acceptability of silver ring splints (SRS) and commercial prefabricated thermoplastic splints (PTS) in treating swan neck deformities in patients with rheumatoid arthritis (RA).
Abstract: In a retrospective, case-control cohort study an assessment was made of the clinical outcome of patients with osteomyelitis treated with a new modality of negative pressure wound therapy, so called negative pressure instillation therapy. In this approach, after surgical debridement, a site of osteomyelitis is treated with negative pressure of at least 300 mmHg applied through polyvinyl alcohol dressing. The polyvinyl alcohol foam is irrigated through the tubes three times a day with a polyhexanide antiseptic solution. In 30 patients (14 males; mean age 52 [range, 26-81]) admitted between 1999 and 2003 with osteomyelitis of the pelvis or lower extremity, we assessed time to wound closure, number of surgical procedures and rate of recurrence of infection as well as need for rehospitalizations. For comparison, a control group of 94 patients (males, 58; mean age 47 [range, 9-85]), matched for site and severity of osteomyelitis, was identified in hospital records between 1982 and 2002. These patients underwent standard surgical debridement, implantation of gentamicin polymethylmethacrylate beads and long-term intravenous antibiotics. In the Instillation group the rate of recurrence of infection was 3/30 (10%), whereas 55/93 (58.5%) of the controls had a recurrence (p<0.0001). Moreover, in those treated with instillation the total duration of hospital stay was shorter and number of surgical procedures smaller as compared with the controls (all p<0.0001). We conclude that in posttraumatic osteomyelitis negative pressure instillation therapy reduces the need for repeated surgical interventions in comparison with the present standard approach.
Abstract: In a prospective randomised study we compared the results of arthroscopic subacromial bursectomy alone with debridement of the subacromial bursa followed by acromioplasty. A total of 57 patients with a mean age of 47 years (31 to 60) suffering from primary subacromial impingement without a rupture of the rotator cuff who had failed previous conservative treatment were entered into the trial. The type of acromion was classified according to Bigliani. Patients were assessed at follow-up using the Constant score, the simple shoulder test and visual analogue scores for pain and functional impairment. One patient was lost to follow-up. At a mean follow-up of 2.5 years (1 to 5) both bursectomy and acromioplasty gave good clinical results. No statistically significant differences were found between the two treatments. The type of acromion and severity of symptoms had a greater influence on the clinical outcome than the type of treatment. As a result, we believe that primary subacromial impingement syndrome is largely an intrinsic degenerative condition rather than an extrinsic mechanical disorder.
Abstract: Improvement of alignment and position of the components in TKAs using Computer Assisted Orthopaedic Surgery (CAOS) has been described. However, much less is known about the accuracy of CAOS in determining the size of the components. The purpose of this study was to evaluate the size of the femoral and tibial component using the CAOS system from Brainlab. The component sizes were compared to pre-operative templating and post-operative scoring the adequateness of size. Forty TKAs (NexGen) were evaluated: 20 using CAOS and 20 conventional. Statistical analysis of the templated and implanted size indicated a fair agreement for the femur (kappa 0.38) and the tibia (kappa 0.35). In the CAOS group significantly more oversizing occurred for the femoral component (p=0.020). No significant difference was found for the tibial component. We conclude there is a risk of oversizing the femoral component of the NexGen system when using CAOS.
Abstract: It was hypothesized that rheumatoid arthritis (RA) patients with a total knee prosthesis that allows axial rotation of the bearing (MB) will show more co-contraction to stabilize the knee joint during a step-up task than RA patients with a fixed bearing total knee prosthesis (FB) where this rotational freedom is absent while having the same articular geometry. Surface EMG, kinematics and kinetics about the knee were recorded during a step-up task of a MB group (n = 5), a FB group (n = 4) and a control group (n = 8). Surface EMG levels of thigh muscles were calibrated to either knee flexion or extension moments by means of isokinetic contractions on a dynamometer. During the step-up task co-contraction indices were determined from an EMG-force model. Controls showed a higher active ROM during the step-up task than the patient group, 96 degrees versus 88 degrees (P = 0.007). In the control group higher average muscle extension, flexion and net moments during single limb support phase were observed than in the patient group. During the 20-60% interval of the single limb support, MB patients showed a significant higher level of flexor activity, resulting in a lower net joint moment, however co-contraction levels were not different. Compared to the control group arthroplasty patients showed a 40% higher level of co-contraction during this interval (P = 0.009). Control subjects used higher extension moments, resulting in a higher net joint moment. Visual analysis revealed a timing difference between the MB and FB group. The FB group seems to co-contract approximately 20% later compared to the MB group. RA patients after total knee arthroplasty show a lower net knee joint moment and a higher co-contraction than controls indicating avoidance of net joint load and an active stabilization of the knee joint. MB and FB patients showed no difference in co-contraction levels, although timing in FB is closer to controls than MB subjects. Since visual analysis revealed a timing difference between the MB and FB group, this may express compensation by coordination. Rehabilitation programs for RA patients should include besides muscle strength training, elements of muscle-coordination training.
Abstract: Loosening of orthopedic hip prostheses is an increasing health problem. In elderly patients with comorbidity,revision surgery may lead to high mortality rates. A less invasive surgical technique is therefore required to reduce these patient risks. To this end a percutaneous gene therapy approach was designed to destroy the periprosthetic loosening membrane, and enable refixing of the hip prosthesis with percutaneous bone cement injections under radiological guidance. In this phase 1/2 dose-escalating gene therapy clinical trial, 12 patients were treated. Toxicity and hip function variables were monitored up to 6 months posttreatment. All patients completed the study and no dose-limiting toxicity was observed. Improvement in walking distance, independence,and pain was demonstrated particularly in patients receiving 3 x 10(10) and 1 x 10(11) viral particles. Taken together, these data show that this gene therapy approach targeted at the interface membrane around a loosened hip prosthesis is a feasible treatment option for elderly patients for whom surgical intervention is not appropriate.
Abstract: Revision surgery for loosened hip prostheses is a heavy burden for elderly patients with comorbidity. As an alternative to surgery we performed a study to stabilize the prosthesis by percutaneous cement injection after removing inflammatory tissue with an intraarticular virus-directed enzyme prodrug approach. Twelve elderly patients with debilitating pain from a loosened hip prosthesis were included in a phase 1 dose-escalating clinical study. The patients were admitted to the hospital for 10 days for an intraarticular vector and prodrug injection, and subsequently for a percutaneous bone cement injection. This paper reports the adverse and serious adverse events of the study. After prodrug injection 9 of 12 patients had gastrointestinal adverse events (nausea, vomiting, and diarrhea), and 8 patients had hepatic adverse events (rise in aspartate aminotransferase and alanine aminotransferase). Five patients developed anemia (World Health Organization grade 1 or 2) from hematomas after cement injection. There were four serious adverse events in the first 6 months after vector injection, but these were not related to gene therapy as judged by an independent safety committee. There was no dose-limiting toxicity. However, the extensive comorbidity in these patients makes it difficult to fully establish the safety of the approach in this small and heterogeneous patient population.
Abstract: To investigate the responsiveness of the Michigan Hand Outcomes Questionnaire (MHQ) in patients with rheumatoid arthritis (RA) who were treated in a multidisciplinary hand clinic.
Abstract: Migration measurements of hip prostheses using marker-based Roentgen stereophotogrammetric analysis (RSA) require the attachment of markers to the prostheses. The model-based approach, which does not require these markers, is, however, less precise. One of the reasons may be the fact that the spherical head has not been modelled. Therefore, we added a 3D surface model of the spherical head and estimated the position and orientation of the combined stem-head model. The new method using a combined stem-head model was compared in a phantom study on five prostheses (of different types) and in a clinical study using double examinations of implanted hip prostheses, with two existing methods: a standard model-based approach and one using elementary geometrical shapes. The combined model showed the highest precision for the rotation about the longitudinal axis in the phantom experiments. With a standard deviation of 0.69 degrees it showed a significant improvement (p=0.02) over the model-based approach (0.96 degrees ) on the phantom data, but no improvement on the clinical data. Overall, the use of elementary geometrical shapes was worse with respect to the model-based approach, with a standard deviation of 1.02 degrees on the phantom data and 0.79 degrees on the clinical data. This decrease in precision was significant (p<0.01) on the clinical data. With relatively small differences in the other migration directions, these results demonstrate that the new method with a combined stem-head model can be a useful alternative to the standard model-based approach.
Abstract: Rotational malalignment is recognized as one of the major reasons for knee pain after total knee arthroplasty (TKA). Although Computer Assisted Orthopaedic Surgery (CAOS) systems have been developed to enable more accurate and consistent alignment of implants, it is still unknown whether they significantly improve the accuracy of femoral rotational alignment as compared to conventional techniques. We evaluated the accuracy of the intraoperatively determined transepicondylar axis (TEA) with that obtained from postoperative CT-based measurement in 20 navigated TKA procedures. The intraoperatively determined axis was marked with tantalum (RSA) markers. Two observers measured the posterior condylar angle (PCA) on postoperative CT scans. The PCA measured using the intraoperatively determined axis showed an inter-observer correlation of 0.93. The intra-observer correlation, 0.96, was slightly better than when using the CT-based angle. The PCA had a range of -6 degrees (internal rotation) to 8 degrees (external rotation) with a mean of 3.6 degrees for observer 1 (SD = 4.02 degrees ) and 2.8 degrees for observer 2 (SD = 3.42 degrees ). The maximum difference between the two observers was 4 degrees . All knees had a patellar component inserted with good patellar tracking and no anterior knee pain. The mean postoperative flexion was 113 degrees (SD = 12.9 degrees ). The mean difference between the two epicondylar line angles was 3.1 degrees (SD = 5.37 degrees ), with the CT-based PCA being larger. During CT-free navigation in TKA, a systematic error of 3 degrees arose when determining the TEA. It is emphasized that the intraoperative epicondylar axis is different from the actual CT-based epicondylar axis.
Abstract: When measuring knee kinematics with skin-mounted markers, soft tissue and structures surrounding the knee hide the actual underlying segment kinematics. Soft-tissue artefacts can be reduced when plate-mounted markers or marker trees are used instead of individual unconstrained mounted markers. The purpose of this study was to accurately quantify the soft-tissue artefacts and to compare two marker cluster fixation methods by using fluoroscopy of knee motion after total knee arthroplasty during a step-up task. Ten subjects participated 6 months after their total knee arthroplasty. The patients were randomised into (1) a plate-mounted marker group and (2) a strap-mounted marker group. Fluoroscopic data were collected during a step-up motion. A three-dimensional model fitting technique was used to reconstruct the in vivo 3-D positions of the markers and the implants representing the bones. The measurement errors associated with the thigh were generally larger (maximum translational error: 17mm; maximum rotational error 12 degrees ) than the measurement errors for the lower leg (maximum translational error: 11mm; maximum rotational error 10 degrees ). The strap-mounted group showed significant more translational errors than the plate-mounted group for both the shank (respectively, 3+/-2.2 and 0+/-2.0mm, p = 0.025) and the thigh (2+/-2.0 and 0+/-5.9mm, p = 0.031). The qualitative conclusions based on interpretation of the calculated estimates of effects within the longitudinal mixed-effects modelling evaluation of the data for the two groups (separately) were effectively identical. The soft-tissue artefacts across knee flexion angle could not be distinguished from zero for both groups. For all cases, recorded soft-tissue artefacts were less variable within subjects than between subjects. The large soft-tissue artefacts, when using clustered skin markers, irrespective of the fixation method, question the usefulness of parameters found with external movement registration and clinical interpretation of stair data in small patient groups.
Abstract: The effect of total ankle replacement on gait is not fully known in terms of joint kinematics, ground reaction force, and activity of the muscles of the lower leg.
Abstract: The hypothesis of this study was that the polyethylene bearing in a rotating platform total knee prosthesis shows axial rotation during a step-up motion, thereby facilitating the theoretical advantages of mobile-bearing knee prostheses. We examined 10 patients with rheumatoid arthritis who had a rotating platform total knee arthroplasty (NexGen LPS mobile, Zimmer Inc. Warsaw, USA). Fluoroscopic data was collected during a step-up motion six months postoperatively. A 3D-2D model fitting technique was used to reconstruct the in vivo 3D kinematics. The femoral component showed more axial rotation than the polyethylene mobile-bearing insert compared to the tibia during extension. In eight knees, the femoral component rotated internally with respect to the tibia during extension. In the other two knees the femoral component rotated externally with respect to the tibia. In all 10 patients, the femur showed more axial rotation than the mobile-bearing insert indicating the femoral component was sliding on the polyethylene of the rotating platform during the step-up motion. Possible explanations are a too limited conformity between femoral component and insert, the anterior located pivot location of the investigated rotating platform design, polyethylene on metal impingement and fibrous tissue formation between the mobile-bearing insert and the tibial plateau.
Abstract: Predictable and adequate transgene expression is essential for clinical gene therapy. Several studies have focused on optimization of transgene expression. In this study the effect of sodium butyrate (NaB) and a ubiquitous chromatin opening element (UCOE) on short-term gene expression after adenovirus-mediated gene transfer in fibroblastic interface cells from periprosthetic tissue in loosened orthopedic implants is investigated.
Abstract: Roentgen stereophotogrammetric analysis generally is accepted as the most accurate method to measure prosthesis migration. A disadvantage of the method is it requires markers in the bone and the prosthesis. Model-based roentgen stereophotogrammetric analysis circumvents the need for markers on prostheses by fitting virtual projections of a three-dimensional surface model of a prosthesis to its actual projections in the roentgen image. We confirmed a model-based roentgen stereophotogrammetric analysis for a tibial component. Using implants with attached markers, we compared model-based roentgen stereophotogrammetric analysis with marker-based roentgen stereophotogrammetric analysis. In addition, we assessed precision of the model-based roentgen stereophotogrammetric analysis with a phantom experiment. The precisions for translations of marker-based and model-based roentgen stereophotogrammetric analysis were 0.06 and 0.11 mm, respectively, and for rotations, the precisions were 0.20 degree and 0.23 degree, respectively. The precisions of model-based roentgen stereophotogrammetric analysis calculated from the phantom data were 0.08 mm for translations and 0.13 degree for rotations. Although model-based roentgen stereophotogrammetric analysis is less precise than marker-based roentgen stereophotogrammetric analysis, its precision is still acceptable for most clinical applications, especially where marker-based roentgen stereophotogrammetric analysis has practical limitations. LEVEL OF EVIDENCE: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.
Abstract: To describe the characteristics, management strategies and outcomes of patients with rheumatic diseases and complex hand function problems referred to a multidisciplinary hand clinic. Assessments (baseline and after three months of follow-up) included sociodemographic and disease characteristics and various hand function measures. The most frequently mentioned impairments and limitations of the 69 patients enrolled in the study pertained to grip, pain, grip strength, and shaking hands. Fifty-six patients received treatment advice, conservative therapy (n=39), surgery (n=12), or a combination of both (n=5). In 38 of 56 patients (68%) the recommended treatment was performed, and 33 completed the follow-up assessment. On average, patients improved, with an increase in grip strength and the Michigan Hand Outcomes Questionnaire scores reached statistical significance. Two-thirds of patients with rheumatic conditions visiting a multidisciplinary hand clinic reportedly followed the treatment advice (recommendations), with an overall trend toward a beneficial effect on hand function. To further determine the added value of a structured, multidisciplinary approach a controlled comparison with other treatment strategies is needed.
Abstract: To prospectively evaluate the association between clinical features and structural abnormalities found at magnetic resonance (MR) imaging in patients with osteoarthritis (OA) of the knee.
Abstract: This retrospective study describes the long-term results of core decompression and placement of a non-vascularised bone graft in the management of avascular necrosis of the femoral head. We treated 80 hips in 65 patients, 18 by a cortical tibial autograft and 62 by a fibular allograft. The mean age of the patients was 36 years (SD 13.2). A total of 78 hips were available for evaluation of which pre-operatively six were Ficat-Arlet stage 0, three stage I, 31 stage IIA, 16 stage IIB, 13 stage III and nine stage IV. A total of 34 hips (44%) were revised at a mean of four years (SD 3.8). Survivorship analysis using a clinical end-point showed a survival rate of 59% five years after surgery. We found a significant difference (p = 0.002) in survivorship, when using a clinical and radiological end-point, between the two grafts, in favour of the tibial autograft. We considered this difference to be the result of the better quality and increased volume of tibial bone compared with that from the trochanteric region used with the fibular allograft. This is a relatively simple, extra-articular and reproducible procedure. In our view core decompression, removal of the necrotic tissue and packing of the cancellous grafts into the core track are vital parts of the procedure.
Abstract: To assess the accuracy of shoulder infiltrations in the subacromial bursa (SAB) by a posterior or an anteromedial approach. Magnetic resonance imaging (MRI) and clinical outcome were used for evaluation.
Abstract: Interest in mobile-bearing total ankle arthroplasty has increased in recent years. However, to our knowledge, no study has focused exclusively on patients with the diagnosis of inflammatory joint disease or has provided a detailed analysis of the risk factors for failure.
Abstract: Fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA) show characteristics of transformation. Because the chicken anemia virus protein, apoptin, induces apoptosis solely in transformed cells, it was investigated whether FLS from patients were more sensitive to apoptin-induced apoptosis than FLS from normal joints obtained from trauma patients.
Abstract: To determine the safety, efficacy and user-friendliness of two different postoperative autologous blood re-infusion systems, an open, randomized, controlled study was performed. Eligible consecutive primary and revision total hip and knee replacement patients were randomized for one of the two systems or for a control group in which shed blood was not re-infused. The nursing staff scored user-friendliness. Patients were monitored after re-infusion. In all three patient groups, a restrictive transfusion trigger was used. Sixty-nine of 70 randomized patients were evaluated. Ease of use, efficacy and safety of both re-infusion systems were comparable. There was no difference in allogeneic blood use between the groups. Thirty per cent of the patients re-infused with autologous blood developed a mainly mild, febrile transfusion reaction. No other adverse reactions were seen. Signs of coagulopathy after re-infusion were not found. In multivariate analysis, autologous re-infusion was an independent factor associated with a shorter hospital stay. Both postoperative autologous blood re-infusion systems were of equal efficacy and safety. The contribution of autologous wound blood re-infusion to reduce allogeneic transfusions must be investigated in a larger study.
Abstract: Interest in mobile-bearing total ankle arthroplasty has increased in recent years. Clinical studies show favorable but varying results, with survival rates between 70% and 90% at 10-year followup. Design-specific differences in early migration patterns might explain variations in the results and modes of failure. Using radiostereometric analysis (RSA) we prospectively followed 15 RA patients with a cementless mobile-bearing total ankle arthroplasty. The American Orthopaedic Foot and Ankle Society ankle score and radiostereometric radiographs were evaluated immediately postoperatively, 6 weeks postoperatively, 3 months, 6 months, and 12 months postoperatively and yearly thereafter. The postoperative clinical results improved. We observed increased migration of the tibial component during the first 3 months, but this stabilized by the 6 month followup. The mean lateral-medial migration was 0.8 mm, distal-proximal migration was 0.9 mm, and posteroanterior migration was -0.5 mm. The latter implies the total resultant migration was in anterior and valgus tilting of this tibial component. However, migration stabilized at 6 months postoperatively. We believe the surgical technique (anterior cortical window for placement) and the method of tibial fixation likely explain this migration. LEVEL OF EVIDENCE: Therapeutic, Level IV. See Guidelines for Authors for a complete description of levels of evidence.
Abstract: Loosening is a major complication in prosthesis surgery. Less invasive alternatives to revision surgery are required to prevent and treat prosthesis loosening. Some experimental therapies investigating alternative treatments exploit the intra-articular space as a route of administration. For efficient, local delivery of therapeutic agents a contained joint space is required. Furthermore, the volume of the joint space determines the concentration of the therapeutic ingredient in the joint.
Abstract: Prosthesis migration in bone inevitably occurs in cemented and uncemented total knee arthroplasty tibial components. Cemented designs as the gold standard give immediate fixation whereas cementless designs need a period of bone ingrowth onto the surface irregularities of the implants. The addition of bioactive coatings may enhance this process of ingrowth. A controlled randomized prospective RSA study was carried out on 26 Duracon implants in a rheumatoid arthritis patient group to evaluate the effect of a periapatite coating on the fixation of the tibial tray. The coated and the noncoated groups were matched for sex, age, body mass index, and HSS Knee Score. Stage of preoperative joint destruction and preoperative and postoperative mechanical leg axis showed no differences. We saw no differences in migration between the two groups, but a trend for lesser translations along and rotations about all three axes in the periapatite group. The periapatite-coated components showed a lower variance in subsidence than did the uncoated components. Both groups also showed a high variance in anterior tilting of the components. The cementless PA-coated Duracon prosthesis used in patients with RA may provide improved fixation of tibial components although we could not demonstrate improvement in this small controlled series. LEVEL OF EVIDENCE: Therapeutic Level II. See the Guidelines for Authors for a complete description of levels of evidence.
Abstract: We conducted a prospective study of the clinical and radiographic variables related to the survival of 114 cementless resurfacing double-cup hip replacements (RHR) with a mean follow-up of 9 (range: 1--16) years. Three patients died, and 22 were unavailable for the final review in 2003. Sixty-one RHRs had to be revised to a total hip replacement. Failure analysis of these revised RHRs showed femoral head and neck resorption under the prosthesis in 33, acetabular protrusion in seven, both femoral and acetabular resorption in 14 and a femoral-neck fracture in three. One hip had dislocated, and there were three hips with unexplained pain. The Kaplan-Meier 5-year mean survival was 92%, the 10-year survival was 47% (95% CI 37--57%) and the 15-year survival was 30% (95% CI 20--40%). Pre-operative joint destruction (grade 1), a high degree of radiological osteoporosis, a body mass index >25 and prosthesis mismatch were significantly related to failure of the RHR. We believe that in young, non-obese patients with pre-operative radiological central destruction but without severe proximal femoral osteoporosis, a resurfacing arthroplasty may have some value. Our failures were mainly due to femoral resorption under the prosthetic femoral component.
Abstract: It remains unknown if and how the polyethylene bearing in mobile bearing knees moves during dynamic activities with respect to the tibial base plate. Marker Configuration Model-Based Roentgen Fluoroscopic Analysis (MCM-based RFA) uses a marker configuration model of inserted tantalum markers in order to accurately estimate the pose of an implant or bone using single plane Roentgen images or fluoroscopic images. The goal of this study is to assess the accuracy of (MCM-Based RFA) in a standard fluoroscopic set-up using phantom experiments and to determine the error propagation with computer simulations. The experimental set-up of the phantom study was calibrated using a calibration box equipped with 600 tantalum markers, which corrected for image distortion and determined the focus position. In the computer simulation study the influence of image distortion, MC-model accuracy, focus position, the relative distance between MC-models and MC-model configuration on the accuracy of MCM-Based RFA were assessed. The phantom study established that the in-plane accuracy of MCM-Based RFA is 0.1 mm and the out-of-plane accuracy is 0.9 mm. The rotational accuracy is 0.1 degrees. A ninth-order polynomial model was used to correct for image distortion. Marker-Based RFA was estimated to have, in a worst case scenario, an in vivo translational accuracy of 0.14 mm (x-axis), 0.17 mm (y-axis), 1.9 mm (z-axis), respectively, and a rotational accuracy of 0.3 degrees. When using fluoroscopy to study kinematics, image distortion and the accuracy of models are important factors, which influence the accuracy of the measurements. MCM-Based RFA has the potential to be an accurate, clinically useful tool for studying kinematics after total joint replacement using standard equipment.
Abstract: The aim of this study was to assess the differences in muscle activity (surface EMG) between a posterior stabilised (PS) total knee design and a mobile bearing (MB) posterior cruciate ligament retaining design in rheumatoid arthritis (RA) patients during a step-up task. Four patients with a PS total knee prosthesis and three patients with a MB total knee prosthesis were selected based on pain score, knee function, range of motion and joint stability. Clinical scores and functional scores were comparable between the two groups pre-operatively and at the 1-year follow-up. Visual analysis of the EMG activity of the main flexor and extensor muscles showed that the activity of both extensor and flexor muscles of the MB group was on average higher compared to the PS group. When the maximum activities of the muscles were compared, the patients in the MB group showed a significant higher maximum peak activity (p<0.05) of the Vastus Medialis (VM), Vastus Lateralis (VL) and Semitendinosus (ST) during step-up than the patients in the PS group. Also the instance of activation of the Vastus Medialis and the Vastus Lateralis was significant earlier in the MB group compared to the PS group. Since the differences between the PS and the MB group did not only show an increase of muscle activity but also an earlier activation of the flexor muscles, this may express compensation by coordination. Rehabilitation programs for RA patients should include besides muscle strength training, elements of muscle-coordination training.
Abstract: The effect of bone cement viscosity and cement mantle thickness on the migration of the Exeter total hip prosthesis was studied in a prospective, randomized, double-blind clinical Roentgen Stereophotogrammetric Analysis study. Forty-one cemented total hip arthroplasty in 39 patients were included and randomized into a low/medium Simplex P cement group and a high-viscosity Simplex AF cement group. At time of stem introduction, 5 minutes after mixing, the Simplex AF was more viscous than Simplex P. No statistical difference existed between the 2 cement groups, for neither translation nor rotation migration data. Subsidence of the stem at 2-year follow-up was 1.1 +/- 0.56 mm for Simplex AF cement and 1.5 +/- 1.00 mm for Simplex P cement. The mean rotation of the acetabular components about the sagittal axis was 1.7 degrees +/- 3.8 degrees in the Simplex AF group and 0.7 degrees +/- 2.1 degrees for the Simplex P group. No effect of cement mantle thickness on migration of neither the acetabular cups nor the femoral stems was found. Although there were no differences in migration data for the cups and the stems, 2 acetabular cups in the Simplex AF group (almost 10%) were revised because of mechanical loosening. Because of these findings, we suggest caution before using this new high-viscosity bone cement for fixation of acetabular components.
Abstract: Loosening is a major complication in prosthesis surgery. To stabilize loosened orthopedic implants, the interface tissue surrounding the implant must be removed. As an alternative to manual removal, we explored the possibility of removing the tissue by gene-directed enzyme prodrug therapy. In the current study we investigated whether interface cells can be transduced by an HAdV-5 vector carrying the E.coli-derived nitroreductase gene and sensitized to the prodrug CB1954.
Abstract: Rheumatoid arthritis (RA) is characterized by inflammation and destruction of synovial joints. Fibroblast-like synoviocytes (FLS) harvested from synovial tissue of patients with RA can invade normal human cartilage in severe combined immunodeficient (SCID) mice and Matrigel basement membrane matrix in vitro. This study was undertaken to investigate the association of these in vitro characteristics with disease characteristics in patients with RA.
Abstract: An historical cohort study was conducted to investigate the rate and extent of neurological recovery in obstetric brachial plexus injury (OBPI) and to identify possible prognostic factors in a cohort of children with OBPI from birth to 7 years. All children (n=56; 31 females, 25 males) with OBPI were evaluated at fixed time intervals by one examiner. They underwent a final neurological examination at a mean age of 3 years 10 months (range 1 to 7 years). Neurological outcome was not as favourable as is often reported: complete neurological recovery occurred in 37 out of 56 children (66%). In half of these there was delayed recovery, in which case complete neurological recovery was assessed from 1.5 to 16 months of age (median age 6.5 months, SD 4.2 months). External rotation and supination were the last to recover and recovered the least. Although biceps function at three months was considered to be the best indicator for operative treatment, external rotation and supination were found to be better in predicting eventual complete recovery. Initial symptoms directly post partum were not found to be prognostic. Functional outcome was mainly reported to be good.
Abstract: Progressive ulnar translocation of the carpus and problems with the ulnar stump have been reported after resection of the distal ulna in rheumatoid arthritis (RA). However this has only occasionally been quantitatively assessed. In this study 24 wrists in 21 patients with RA were followed up for an average of 100 months after resection of the distal ulna. An additional 24 wrists in 14 non-operated RA patients were followed up for 92 months. In a retrospective radiographic analysis we demonstrate similar increases in ulnar translocation and ulnar-carpal distances in both groups.
Abstract: Between 1990 and 2001, 292 patients with acute Achilles tendon rupture were admitted to our institution. Depending on the day of admission patients were allocated either to the Department of Trauma Surgery or to the Department of Orthopaedics. Two hundred and twelve patients (mean age 37+/-9.4 years) were treated with surgical suture followed by plaster for 6 weeks. Eighty patients were treated non-surgically with splinting for 12 weeks. For both groups mean follow-up was 6+/-3 years. There were 14 re-ruptures, ten after surgical repair and four after non-surgical treatment. In the surgical group there were seven major wound problems, 11 minor wound complications and six patients with complaints from the sural nerve. In the non-surgical group one patient suffered a pulmonary embolism after a re-rupture, 3 months after the initial rupture. There was no difference in mean ankle score and patient-satisfaction score between groups. Only 52% regained their original sports activity level, slightly better in the surgically treated group. With a non-significant difference in re-rupture rate but relatively more complications after surgical repair, non-surgical treatment is preferred. With a slightly better recovery of sports activity after surgical repair, this might be used as an argument for surgical treatment in young athletes.
Abstract: To compare an optimized water selective balanced steady-state free precession sequence (WS-bSSFP) with conventional magnetic resonance (MR) sequences in imaging cartilage of osteoarthritic knees.
Abstract: The purposes of this study were to determine the prevalence of and the association between shoulder contracture and osseous deformity in a cohort of children with an obstetrical brachial plexus injury and to identify the risk factors for these complications.
Abstract: Description of shoulder sequelae in obstetrical brachial plexus injury (OBPI) patients who had spontaneous functional recovery, in the context of historical and current conservative methods of treatment.
Abstract: To analyze the -2849 A/G interleukin-10 (IL-10) promoter polymorphism, which is associated with high (AG/GG) and low (AA) IL-10 production, in a cohort of rheumatoid arthritis (RA) patients and controls in order to gain a better understanding of its role in the incidence and progression of RA.
Abstract: Management of the patient with rheumatoid arthritis (RA) requires a multidisciplinary approach, the role of the surgeon being to improve functional ability for the patient by reconstructing a deteriorated joint by total joint arthroplasty (TJA). An advantage of prosthetic evaluation over pharmacological medication evaluations is that the 'compliance' of the patient with the treatment (i.e. the TJA) is 100%, even at long-term follow-up. However, long-term follow-up of prosthesis evaluation is as difficult as the evaluation of any other intervention. Although the goal of any intervention on an RA patient is to improve functional ability, and thus self-support, of the patient, objective evaluation of the surgical procedure, and of its impact on the patient, can be difficult. The potential chronic course of RA makes evaluation of a specific surgical procedure and its effect on the patient difficult to interpret. The success of the TJA is generally judged on a survivorship analysis at 10 or 15 years in national registries (i.e. >40000 implants); revision surgery is used as an end-point for survival of the TJA. With a mean 90% survival at 10-year follow-up, total hip arthroplasty and total knee arthroplasty may be considered gold-standard TJA procedures for the patient. While revision is the end-point, the course to this end-point starts with progressive micromotion of the prosthesis. The effect of prosthetic changes, and of medication on prosthesis migration, can be measured very accurately by radiostereometry. The latter measures the actual performance of the TJA in the bone. Next to these more procedure-oriented evaluations, patient-oriented evaluations (e.g. quality of life, patient expectations) are of importance in judging the impact of the TJA on the RA patient. These evaluations provide evidence that the pre-operative status of the joint/extremity determines the extent of post-operative functional gain. Thus, postponing TJA for too long will give less functional benefit.
Abstract: We studied all Stanmore total hip arthroplasties (THA, n=325) implanted at our center between 1980 and 1990. Seven patients (seven hips), followed for less than 12 months, were excluded. Five hips were lost at follow-up. The mean follow-up was 117 (12-252) months. A total of 18 hips were revised, with median time between operation and revision 163 months. With revision as endpoint, a survival rate analysis was calculated. The mean survival for all hips was 82% at 18 years (95% confidence interval 64-101%). For hips with rheumatoid arthritis, the survival rate was 58%, whereas in osteoarthritic hips the rate was 95% after 18 years. A high proportion of acetabular loosening was seen in rheumatoid hips.
Abstract: A prospective radiostereometric analysis (RSA) study of 18 patients with cemented revision hip surgery and impaction grafting with an Exeter stem was done with a follow-up of 2 years for all patients. All factors that could influence migration (ie, micromotion) of the stem were analyzed with a repeated measurements analysis of variance. Two groups could be identified: a stable group and a continuous migrating group. Two factors significantly influenced micromotion during the follow-up measurements. The first factor was the Paprosky classification (the bigger the defect, the higher the micromotion). The second factor was cement mantle defects in > or =1 Gruen zones. The migrating hip stems had more Gruen zones with cement mantle defects (45%) compared with the stable prostheses (21%). The effect of the first factor on micromotion was limited and probably clinically less relevant. Because the cement mantle defects found in this study were caused by poor instrumentation, the second factor stresses the importance of good instrumentation, which is essential to make this technically demanding technique effective in creating a stable stem-allograft construct in the defective femoral canal.
Abstract: Matrix metalloproteinases (MMPs) have a pivotal role in the destruction of cartilage in rheumatoid arthritis (RA), which is mediated by the fibroblast-like synoviocytes (FLS).
Abstract: The decision whether to retain or resect the posterior cruciate ligament in total knee arthroplasty is at present determined clinically by preoperative radiological variables focusing upon the amount of joint destruction, and subsequent soft tissue contractures. However, these variables give only indirect information on the histological integrity and proprioceptive properties of the posterior cruciate ligament.
Abstract: Two men, aged 65 and 27 years, had persistent dysesthesia of digits IV and V 18 and 8 months, respectively, after conservative treatment of dislocated comminuted clavicular fractures. In both patients, the fracture was found to have healed poorly. There was pseudoarthrosis, shortening and malrotation. Following surgical decompression of the neurogenic structures by elongation and internal fixation of the clavicle, motor and sensory functions recovered completely. The incidence of clavicular fractures is high, but complications are rare. Symptom recognition and timely treatment can prevent irreversible nerve damage.
Abstract: We used scanning electron microscopy in combination with X-ray microanalysis to evaluate Co-, Cr-, and Mo-based human femoral hip prostheses. In total, 23 retrieved implants and four new implants were included in this study. Scanning electron microscopy of the polished surface of all arthroplasties showed, in addition to the polishing marks, small round and angular holes or pits. Other types of surface irregularities were interpreted as wear or corrosion of the metal compound. In all cases studied, corrosion propagated from holes at the surface of the polished prosthesis heads, in some cases also along phase boundaries. X-ray microanalysis of the intact prosthetic surface showed a relative composition of the elements Co, Cr, and Mo, which was in agreement with the manufacturer's information (63:33:4%). However, X-ray microanalysis spot analysis of the surface holes showed deviation in the relative composition of the elements Co, Cr, and Mo and also the presence of Si, Ti, and Al. Furthermore, Ti and Al could be traced back at an artificially made fracture plane of a new prosthesis. Therefore, Ti and Al have to be present during the manufacturing process. These impurities in the metal prosthesis alloy may create a galvanic element with the Co, Cr, Mo alloy of the implant. If this is the case, such a galvanic element in combination with the electrolyte environment formed by body fluids, can induce galvanic corrosion with release of metal particles.
Abstract: The accuracy of digital Roentgen stereophotogrammetric analysis (RSA) was compared to the accuracy of a manually operated RSA system. For this purpose, we used radiographs of a phantom and radiographs of patients. The radiographs of the patients consisted of double examinations of 12 patients that had a tibial osteotomy and of double examinations of 12 patients that received a total hip prosthesis. First, the radiographs were measured manually with an accurate measurement table. Subsequently, the images were digitized by a film scanner at 150 DPI and 300 DPI resolutions and analyzed with the RSA-CMS software. In the phantom experiment, the manually operated system produced significantly better results than the digital system, although the maximum difference between the median values of the manually operated system and the digital system was as low as 0.013mm for translations and 0.033 degrees for rotations. In the radiographs of the patients, the manually operated system and the digital system produced equally accurate results: no significant differences in translations and rotations were found. We conclude that digital RSA is an accurate, fast, and user friendly alternative for manually operated RSA. Currently, digital RSA systems are being used in a growing number of clinical RSA-studies.
Abstract: The prevalence of rheumatoid arthritis is about 1%. Loss of independence during daily activities is closely related to the multiple joint involvement of these patients. Also, chronic systemic autoimmune diseases and the extra-articular lesions cause considerable comorbidity. Goal of medical treatment is to reduce disease activity and local joint destruction. The surgical treatment consists of joint protective surgery and joint reconstructive surgery. The former procedure inhibits rapid progression of joint destruction by eradicating the bulk of synovial tissue. The latter procedure compensates for functional loss of an extremity by arthroplasties (both endoprostheses and arthrodeses) to increase the patient's independence. The perfect long-lasting functional prosthesis is available for some joints (hip and knee), but still in development for other joints (e.g. finger joints). In case of surgical reconstruction, a plan for possible complications (e.g. loosening) and their functional implications for the specific patient, should be part of the surgical indication policy. The outcome after a surgical procedure is closely related to preoperative patient factors (e.g. joint destruction) and the surgical expertise. Co-ordination of the treatment plan has to be done by the rheumatologist in close conjunction with the orthopedic/rheuma surgeon.
Abstract: This case presents the imaging features of a posterior shoulder dislocation complicated by a rare but surgically relevant lesion of the posterior labrum. Due to the attachment of the posterior capsule to the posterior portion of the labrum, which in itself is attached to the posterior scapular periosteum, stripping of the labrum by the posterior capsule resulted in a posterior labrocapsular periosteal sleeve avulsion.
Abstract: A prospective, randomized, double-blind study was performed to evaluate three different means of fixing tibial components during total knee arthroplasty. Eleven components fixed with cement, ten hydroxyapatite-coated components fixed without cement, and ten noncoated components fixed without cement were studied. A posterior cruciate ligament-retaining total condylar implant was used. Micromotion of the components was assessed with roentgen stereophotogrammetric analysis during the two-year follow-up period. There were no significant differences among the patients with regard to age (mean [and standard deviation], 68 +/- 11.6 years), body-mass index (mean, 23 +/- 2.8 kilograms per square meter), or stage of osteoarthrosis (mean, 4 +/- 2.4 according to the classification system of Ahlback and 5 +/- 0.6 according to that of Larsen et al.). The diagnosis was osteoarthrosis in five knees, and it was rheumatoid arthritis in twenty-six. The clinical scores were similar among the study groups. According to the system of the Knee Society, the mean preoperative functional score was 10 +/- 2.9 points and the mean preoperative knee score was 24 +/- 3.2 points. At the two-year follow-up evaluation, these scores were 41 +/- 8.3 and 79 +/- 3.2 points, respectively. A significant difference with regard to micromotion was found between the noncoated components fixed without cement and the hydroxyapatite-coated components fixed without cement as well as between the noncoated components fixed without cement and the components fixed with cement (p < 0.001, analysis of variance). The hydroxyapatite-coated components fixed without cement and the components fixed with cement both had far less micromotion along the longitudinal axis (subsidence) throughout the follow-up period than did the noncoated components fixed without cement. At the two-year follow-up evaluation, the subsidence of the noncoated components was -0.73 +/- 0.924 millimeter, the subsidence of the cemented components was -0.05 +/- 0.109 millimeter, and the subsidence of the hydroxyapatite-coated components was -0.06 +/- 0.169 millimeter. The cemented components as well as the hydroxyapatite-coated components also had less translation along the transverse axis (p < 0.001, analysis of variance) and the sagittal axis (p < 0.001, analysis of variance) compared with the noncoated components. In conclusion, micromotion of hydroxyapatite-coated tibial components fixed without cement was similar to that of tibial components fixed with cement. Therefore, hydroxyapatite, a biological mediator, may be necessary for the adequate fixation of tibial components when cement is not used.
Abstract: A method for the detection of micromotion of a metal-backed hemispherical acetabular cup is presented and tested. Unlike in conventional roentgen stereophotogrammetric analysis, the cup does not have to be marked with tantalum markers; the micromotion is calculated from the contours of the hemispherical part and the base circle of the cup. In this way, two rotations (tilt and anteversion) and the translations along the three cardinal axes are obtained. In a phantom study, the maximum error in the position of the cup's centre was 0.04 mm. The mean error in the orientation of the cup was 0.41 degree, with a 95% confidence interval of 0.28-0.54 degree. The in vivo accuracy was tested by repeated measurement of 21 radiographs from seven patients. The upper bound of the 95% tolerance interval for the translations along the transversal, longitudinal, and sagittal axes was 0.09, 0.07, and 0.34 mm, respectively: for the rotation, this upper bound was 0.39 degree. These results show that the new method, in which the position and orientation of metal-backed hemispherical cup is calculated from its projected contours, is a simple and accurate alternative to attaching markers to the cup.
Abstract: The position of the patellar component and patellofemoral symptoms were assessed in a series of 72 cemented polyethylene patellar components in total condylar arthroplasties. A small (25 mm) component was used. The minimum follow up was 2 years and maximum 3 years. A lateral retinacular release was carried out in 22 knees. Clinical results were assessed by questionnaire and 86% had no patellofemoral symptoms. The mean postoperative patellar height was not changed compared to the preoperative height. Lateral placement of the patellar component was associated with both increased medial tilt and lateral subluxation. The component should be inserted so that its centre is slightly medial to the centre of the bone.
Abstract: The purpose of this study was to compare the intermediate results of total hp arthroplasty with a cemented, collarless, femoral prosthesis design (Exeter, Howmedica, Middlesex, UK and CPT, Zimmer, Warsaw, IN) with those of a cementless, collarless, porous-coated femoral component (PCA, Howmedica). A total of 151 hips in 128 patients were reviewed. In the cemented group, 85 Exeter-CPT prostheses were used in 71 patients with an average follow-up period of 6.5 years. In the uncemented group, 66 PCA prostheses were placed in 57 patients with an average follow-up period of 7 years. Harrington hip scores improved from 50.1 to 80.7 for the PCA group and from 49.5 to 87.3 for the Exeter-CPT group. The patient satisfaction rates were 89 and 96%, respectively. Sixty-eight patients with Exeter or CPT prostheses had excellent function and no significant thigh pain after 2 years. One Exeter stem was revised 10 years after the primary surgery because of aseptic osteolysis due to cement defect. Two Exeter sockets were revised because of aseptic loosening. In the PCA group, the incidence of thigh pain that persisted beyond 2 years was 39.4%, and there were high incidences of distal cortical hypertrophy (66.6%) and bead loosening (45.5%). Sixteen hips were revised for aseptic stem loosening of the socket. The cementless ingrowth stems failed earlier (around 5 years), whereas the cemented stems continued to perform well past 14 years. In this study, the cemented, collarless, tapered, femoral prosthesis gave results superior to those of the uncemented collarless, porous-coated anatomic design at an average follow-up period of 7 years (range, 2-14 years).
Abstract: The findings of radiographic studies have suggested that the cementing of an implant with a polished tapered stem into a bed of impacted bone allograft may provide adequate function of the joint and may restore bone in the proximal part of the femur. However, radiographs of hips with cancellous bone graft adjacent to cement are difficult to interpret, and the viability of impacted bone graft that is adjacent to cement and its capability for remodeling are unclear. To evaluate this interface further, we obtained biopsy specimens from the proximal part of the femur at the time of removal of trochanteric wires from four patients eleven to twenty-seven months after revision hip arthroplasty with cement and impaction grafting. Three relatively ill defined zones were identified histologically: an inner zone consisting of bone cement, fibrous tissue, and partially necrotic trabeculae with evidence of bone-remodeling; a middle zone consisting of viable trabecular bone and probable formation of so-called neocortex with fewer particles of bone cement; and an outer zone consisting of viable cortex. Fibrous tissue was present around some of the incorporating fragments of bone graft, but no continuous fibrous membrane was seen. Particles of cement were identified, but no polyethylene debris was visible on examination with light microscopy. The results demonstrated remodeling of bone and at least partial restoration of bone stock in the proximal part of the femur after revision arthroplasty with cement and impaction grafting.
Abstract: A 36 year old woman with a history of chronic renal failure secondary to acute glomerulonephritis sustained an injury to the tendon of the triceps brachii in her right arm. Magnetic resonance imaging showed an incomplete rupture of the tendon. The injury was successfully treated conservatively.
Abstract: The results of primary total knee arthroplasty in patients with a follow-up of 4-10 years are presented. The study population consisted of osteoarthritis as well as rheumatoid arthritis patients. Both groups were analyzed separately for postoperative pain reduction at rest and during activity, as well as for improvement of some daily activities (walking distance, stair climbing). Pain reduction at rest and during activity was maintained during the follow-up period of 4-10 years. The walking distance and the ability to climb stairs improved during the first few postoperative years, but declined in the later postoperative years. Survival curve analysis of the total knee arthroplasty showed good results for osteoarthritis as well as rheumatoid arthritis (estimated probability of survival of the prosthesis at 10 years' follow-up was 94%).
Abstract: Survivorship analysis, which is often encountered in the medical literature, is used to calculate the probability of a certain event, such as failure of a prosthesis, as a function of the time elapsed since an operation. Possible pitfalls in the use of this method are related to the size of the population of patients and the definition of how the outcome is measured. We studied the outcomes of 204 total knee arthroplasties in 165 patients, using six different end-points, in order to illustrate these problems. Survivorship estimates that are cited without confidence intervals have little clinical value.
Abstract: We compared our standard method of data presentation in the operating room (i.e., using "front end" equipment) with a newly developed, computerized monitoring system called the data acquisition and display system. These two systems differed in that data presentation using the standard front-end equipment was scattered and poorly structured, whereas data obtained from the newly developed system were unified and integrated. To effect the comparison, we examined the "controllability" (i.e., the precision of control) by the anesthesiologist of hemodynamic variables: arterial systolic, mean, and diastolic pressures, mean pulmonary artery pressure, mean central venous pressure, and heart rate. Controllability was assumed to be an indictor of the quality of anesthesia. All perioperative data were stored every 15 seconds on a floppy disk, and these data were available for analysis. The controllability was quantified by calculating the surface area of the signal of a variable outside a defined control zone; the smaller this surface area, the greater the controllability. A Mann-Whitney-Wilcoxon statistical test was done to test whether the two different data presentation systems would result in different levels of controllability (the first zero hypothesis). A Kruskal-Wallis test was done to examine the "inter-anesthesiologist variability" between the two systems (the second zero hypothesis). Our data showed great variability. Looking for factors that might explain this, we found that if preoperative systolic blood pressure was greater than 160 mm Hg and diastolic pressure was greater than 95 mm Hg, hemodynamic variables fluctuated more widely. We could show no differences in controllability when the two systems were compared overall.(ABSTRACT TRUNCATED AT 250 WORDS)
