Abstract: Femoral intramedullary canal referencing is used by most knee arthroplasty systems. Fat embolism, activation of coagulation, and bleeding may occur from the reamed canal. The purpose of our study was to evaluate a new extramedullary device that relies on templated data. We randomized 100 consecutive patients undergoing primary total knee arthroplasty through a limited parapatellar approach to use of either standard intramedullary femoral instruments (IM group) or a new extramedullary device (EM group). The extramedullary instrument was calibrated using templated data obtained from a preoperative full-limb weightbearing anteroposterior view of the knee. In both groups, an intraoperative double check was performed using an extramedullary rod referring to the anterosuperior iliac spine. Femoral component coronal alignment was within 0 degrees +/- 2 degrees of the mechanical axis in 84% of the IM group and 86% of the EM group. Sagittal alignment of the femoral component was 0 degrees +/- 2 degrees in 78% of the IM group and 90% of the EM group. We observed no difference in the average operative time between the two groups. The two groups showed similar postoperative blood loss. Extramedullary reference with careful preoperative templating can be safely used during TKA. LEVEL OF EVIDENCE: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Abstract: Knee complications and function were analyzed in patients with 2 different posterior-stabilized total knee arthroplasty (TKA) designs, Optetrak 913 and Insall-Burstein II. Three hundred Insall-Burstein II knees with mean follow-up of 8 years (range: 5-9 years) and 300 Optetrak knees with mean follow-up of 6 years (range: 5-7 years) were studied. Lateral retinacular release was performed in 30% of Insall-Burstein II patients and 16% of Optetrak patients (P = 0.001), and patellar clunk was 4% for the Insall-Burstein II prosthesis and 0.3% for the Optetrak prosthesis (P = 0.003). No statistically significant differences in dislocation, fracture, or loosening rates were observed between the 2 groups. Knee Society scores were similar in 2 groups of 50 patients brought back to the office. Mean Knee Society knee scores were 92 and 94 for the Insall-Burstein II and Optetrak groups, respectively (P > 0.05), and function scores were 80 and 84 for the 2 groups, respectively (P > 0.05). At mid-term follow-up, Optetrak patients were less likely than Insall-Burstein II patients to require lateral retinacular release and experience patellar clunk.

Abstract: Between December 1996 and April 2003, 26 consecutive femoral component revisions in 24 patients were performed with an extensively hydroxyapatite-coated femoral stem. Two patients were lost to follow-up, and two patients died of unrelated causes. Of the 22 femoral revisions in 20 patients, there was a 0% incidence of mechanical loosening at average follow-up of 3.2 years (2-6.3 years). The Harris Hip Score improved from 59 (36 to 83) to 95 (84 to 100) postoperatively (p < 0.001). Rate of revision was 18.2% (4.5% for sepsis, 9.1% for instability, and 4.5% for polyethelene wear). All 22 femoral components had evidence of bone ingrowth. The extensively coated hydroxyapatite stem in this series produced excellent clinical results with a low incidence of thigh pain (4.5%) and severe stress shielding (4.5%).

Abstract: Two hundred forty-eight constrained condylar total knee arthroplasties consecutively implanted without the use of diaphyseal stem extensions were studied in 180 patients. Preoperative deformity was severe (82% Ahlbäck grade 4-5). One hundred ninety-two knees (148 patients) were reviewed at mean 47-month follow-up (range: 24-72 months). Knee Society score improved from 36 to 89 points, and function score improved from 42 to 76 points. Failure rate was 2.5% (2 infections, 1 aseptic loosening, 1 supracondylar femoral fracture, and 1 tibial post fracture). Five (2.5%) knees had patellofemoral complications. Nonprogressive radiolucent lines were present in 16% of cases. Use of a nonmodular constrained condylar knee for primary severely damaged knees demonstrated reliable short- to mid-term results with a low complication rate and questioned the routine use of intramedullary stem extensions in all such cases.

Abstract: BACKGROUND: Radiographic assessment of the patella after total knee arthroplasty is typically performed with use of static, unloaded views that may not reproduce the in vivo patellofemoral kinematics. The purpose of the present study was to evaluate and validate the reliability and reproducibility of a weight-bearing radiographic assessment of the patellofemoral joint in patients who have undergone total knee arthroplasty. METHODS: Radiographs were made for 100 knees in sixty-nine patients who had undergone total knee arthroplasty. Radiographic assessment of the patellofemoral joint was performed with use of both the standard Merchant axial view and a modification of that view. The Merchant axial view was modified by positioning the standing patient in the semi-squatted position with the knees in 45 degrees of flexion. The relationship between the x-ray source, the angle of incidence on the joint, and the cassette position was kept unchanged from the original view. The standing position and consequent muscle involvement were the only differences. RESULTS: Compared with the standard Merchant axial view, the weight-bearing axial view showed a number of patellofemoral tracking changes. Specifically, lateral tilt and subluxation of the patella were significantly reduced; the rate of exposed, uncovered patellar bone contact with the femoral trochlea was significantly increased; and radiographic evidence of maltracking was more closely correlated with clinical symptoms. CONCLUSIONS: An axial weight-bearing radiographic view with the patient in the semi-squatting position was developed to reproduce patellofemoral joint loading. This view demonstrates that the position of the patella, as seen on the standard unloaded Merchant view, changes during squatting. Utilization of this axial weight-bearing view to evaluate total knee arthroplasty may provide additional information over standard radiographic views.

Abstract: Valgus deformity correction with total knee arthroplasty is challenging. We hypothesized selective release of the tight lateral structures (pie-crusting technique), and of the lateral retinaculum in case of patellar maltracking, would obtain and maintain correction of the frontal plane deformity, restore patellar tracking and function, and avoid the complications of the extensive releases, including lateral condyle avascularity and residual lateral instability. We followed 48 patients with 53 valgus knees who underwent TKA and were followed a minimum of 5 years (mean, 8 years; range, 5-12 years). Soft tissue balancing of the lateral structures was performed with the pie-crusting technique. We employed either a fixed posterior stabilized or a mobile implant. A lateral release was performed in 67% of the cases. We observed one postoperative complication, a transient postoperative peroneal nerve palsy that spontaneously completely recovered. In 51 of the 53 knees (96%) we achieved alignment within 5 degrees from neutral. One patient had varus instability in extension. No component was revised. The pie-crusting technique reliably corrects moderate to severe fixed valgus deformities with a low complication rate and reasonable mid-term results. The multiple punctures allow gradual stretching of the lateral soft tissues and preservation of the popliteus tendon reducing the risk of posterolateral instability. LEVEL OF EVIDENCE: Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.

Abstract: In a prospective randomized double-blind study we compared the postoperative recovery and early results of two groups of 30 patients having total knee arthroplasty with minimally invasive techniques using either a mini-subvastus or a modified "quadriceps-sparing" approach. All knees were implanted with the same posterior-stabilized prosthesis (LPS-Flex, Zimmer, Warsaw, IN) by the same surgeon with the same dedicated set of downsized instruments. Epidural anesthesia with the same postoperative analgesia and rehabilitation protocol was used in all patients. Evaluation was performed preoperatively, postoperatively in the first week, and at 1 and 3 months. In five cases in the "quadriceps- sparing" group, the incision was extended a few cm to facilitate exposure. Tourniquet time, estimated blood loss, and postoperative pain were similar in the two groups. Active straight leg raising was achieved half a day earlier, on average, in the mini-subvastus group (1.9 vs 1.4 days). Average maximum active flexion was similar in the two groups at each interval, and reached 117 degrees and 119 degrees at 3 months for the mini-subvastus and "quadriceps-sparing" group, respectively. We believe there was no difference between the mini-subvastus and "quadriceps-sparing" approach in relation to short term recovery or early results.

Abstract: Avoiding stem extensions in total knee arthroplasties may decrease operative time, prosthetic cost, and canal invasion at surgery. A constrained condylar knee implant without stem extensions also likely will be easier to revise and will eliminate the risk of end of stem pain. Our hypothesis was that a constrained condylar knee implant for primary severely deformed knees would show excellent midterm results with a low rate of aseptic loosening, even without diaphyseal-engaging stems. We retrospectively reviewed 70 consecutive primary constrained condylar knee implants without stem extensions from 1998 to 2001 in 61 patients with knees in 15 degrees valgus or greater. Forty-nine patients (55 knees) were followed up for 44.5 months (range, 2-6 years). Outcome was assessed using the Knee Society scoring system. Knee Society score and functional scores improved from 34 points and 40 points to 93 and 74 points, respectively. No radiographic loosening or wear was found. There were no peroneal nerve palsies, and no patients had flexion or medial instability. One patient was affected by chronic patellar dislocation. Constrained condylar knee implants in patients with severe valgus deformity resulted in pain relief and improved function, without substantial complications at midterm followup, without diaphyseal-engaging stem extensions. Level of Evidence: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Abstract: Patellofemoral complications after total knee arthroplasty (TKA) can result in substantial dissatisfaction with the procedure for some patients. In assessing outcomes of TKA, however, there is often a discrepancy between patellofemoral symptoms and the results obtained by conventional scoring and radiographic analysis. We asked whether a new scoring system and weightbearing radiographic view would more accurately represent patellofemoral kinematics and explain related complications. Sixty-nine patients (100 knees) who underwent posterior-stabilized TKA between 1994 and 1997 were included for clinical and radiographic evaluation. A new patella score was developed to rapidly determine complications, ranged from 0 to 100 points, and included ratings for subjective and objective aspects of TKA. A new weight-bearing axial radiographic view was devised by positioning the standing patient in a semisquatted position. Measurements for patella alignment (tilt and subluxation) were performed. Preoperative Knee Society knee and function scores were 43 +/- 5 points, and 39 +/- 15 points, respectively. Postoperatively, scores increased to 93 +/- 8 and 89 +/- 8 points, respectively. The patella score averaged 89 +/- 8 points and showed satisfactory interobserver variability. The new weightbearing radiographic view demonstrated sources of patellofemoral symptoms. We report a new scoring system and weightbearing view that are easy to use and more accurately represent patellofemoral kinematics than do conventional methods of analysis.

Abstract: The development of new instrumentation and techniques has led to the rapid advancement of less invasive surgical approaches in total knee arthroplasty (TKA). Compared to the standard approach, minimally invasive surgery (MIS) in TKA was shown to reduce postoperative pain, blood loss, and hospitalization time, and to improve functional recovery. Growing experience with MIS-TKA has defined the proper indications for this technique. With a limited exposure, the skin, capsular tissues, and bone surfaces receive higher stresses because of the retraction required. Several complications relating to the MIS learning curve are now being reported. The reliability of a TKA procedure performed through a mini-incision, and its success, seems to depend on patient selection, surgeon experience, and surgical environment.

Abstract: The purpose of this prospective randomized study was to compare the postoperative recovery and early results of 2 groups of patients undergoing total knee arthroplasty: 107 patients received an established fixed-bearing posterior-stabilized prosthesis (Legacy Posterior Stabilized [LPS]), and 103 patients the meniscal-bearing prosthesis (Meniscal Bearing Knee [MBK]). Surgical procedures were the same for both groups except for posterior cruciate ligament management, which was sacrificed in the LPS group and spared but completely released from the tibia in the MBK group. At an average follow-up of 36 months, knee, function, and patellar scores were comparable in both groups. The LPS group showed a significantly higher maximum flexion than the MBK group (112 degrees vs 108 degrees). Using a fixed-bearing or a mobile-bearing design did not seem to influence the short-term recovery and early results after knee arthroplasty. Key words: total knee arthroplasty, mobile bearing, knee prosthesis, meniscal-bearing knee, posterior stabilized, prospective randomized.

Abstract: One of the primary goals in the perioperative care of orthopaedic patients undergoing surgery is the avoidance of allogeneic transfusion. There are a number of ways to lessen blood loss during surgical intervention including regional hypotensive anesthesia, careful and atraumatic surgical technique, and coagulation of bleeding surfaces. Achieving coagulation is difficult in spinal and arthroplasty procedures because of the large cancellous surfaces that are vascular and are not amenable to ligature or thermal coagulation. All measures of autologous blood salvage should be used including preoperative deposit of autologous blood, hemodilution techniques, intraoperative salvage (when appropriate), and postoperative retrieval and reinfusion. The use of perioperative recombinant erythropoietin is also a useful adjunct to promote stimulation of the bone marrow and increased red cell production. Although many infectious diseases that are transmitted through allogeneic blood transfusions have been lessened by better screening techniques, there is still potential life threatening reactions and viral transmissions that may be avoided by comprehensive blood management in joint arthroplasty.

Abstract: Flexion and extension gap heights were measured in 50 consecutive primary posterior-stabilized total knee arthroplasties (TKAs) to determine whether posterior cruciate ligament (PCL) release or re-establishment of the posterior condylar recess increased gap width. After PCL release, a slight symmetrical increase was noted in both gaps. In extension, gap width increased on average 1.3 mm and 1 mm in the medial and lateral compartments, respectively. The same pattern was observed in flexion, averaging 1.3 mm medially and 1.3 mm laterally. Another increase in the two gaps was observed after the posterior condylar osteophytes were removed and the posterior recess was re-established. The gaps in extension increased, with respect to the base-line value, on average 1.8 mm medially and 1.8 mm laterally, whereas flexion increased an average 2 mm medially and 2.2 mm laterally. No statistical differences were noted between flexion and extension gaps. No independent differences between the flexion and extension gaps were found in any surgical phase. Posterior cruciate ligament removal and re-establishment of posterior condylar recess does not require additional consideration in gap balancing during posterior-stabilized TKA.

Abstract: This retrospective study reviewed the long-term experience with high tibial osteotomy and determined which factors influence the results. Between 1980 and 1989, 120 closing wedge high tibial osteotomies for varus gonarthrosis were performed in 102 patients. Twenty-nine knees were excluded because the patients died (17 knees), were bedridden (7 knees), or lost to follow-up (5 knees). Thirty of the remaining 91 knees had a conversion to total knee replacement (TKR) after 11 years on average, leaving 61 knees with a high tibial osteotomy available for clinical and radiographic evaluation at an average follow-up of 15 years (range: 10-21 years). Of the 91 knees, excellent/good results were found in 49% and fair/poor in 51%. Anatomical femorotibial angle in the 61 knees at follow-up averaged 4.7 degrees +/- 5 degrees of valgus (range: 3 degrees varus to 23 degrees valgus). Alignment obtained at consolidation changed with varus recurrence at follow-up in 14% of 61 knees and did not correlate with the clinical results. Twelve (19%) knees showed a patella baja (Caton ratio <0.6) at follow-up, which correlated with patients immobilized postoperatively by a cylinder cast (P=.04). A valgus alignment at consolidation between 8 degrees and 15 degrees, good muscle strength, and male gender correlated with better results (P<.05). Survivorship analysis, considering an unsatisfactory result or revision to TKR as the endpoint, was 96% at 5 years, 88% at 7 years, 78% at 10 years, and 57% at 15 years. High tibial osteotomy provides symptomatic relief for approximately 10 years, but is unlikely to provide permanent relief.

Abstract: We prospectively studied 100 Insall-Burstein Posterior Stabilized II total knee arthroplasties (Zimmer Inc, Warsaw, IN) consecutively implanted in 91 patients with osteoarthritis. We reviewed 92 knees in 85 patients at a mean follow-up of 7.5 years (range, 5.3-9.5 years). According to the Knee Society score, 78 (85%) results were excellent, 11 (12%) were good, and 3 (3%) were fair or poor. The unsatisfactory results were attributed to patellofemoral pain with a low patella (2 knees) and to valgus alignment and medial laxity (1 knee). Flexion at follow-up averaged 116 degrees. Nonprogressive radiolucent lines were present around 30% of the tibial components. There was only 1 small osteolytic lesion around the tibial plateau. We observed no aspetic loosening, infection, or patella stress fracture. Survivorship analysis in the worst-case scenario showed a 90.9% success rate at 8 years.

Abstract: Three different knee replacements, with three trochlear designs, were prospectively evaluated clinically and radiographically for patellar function and presence of patellar complications. They included the Insall-Burstein (IB) I and the IB-II (posterior cruciate ligament substituting) and the Meniscal Bearing Knee (MBK; posterior cruciate ligament recession). The trochlea of the IB-I was short and shallow with an anterior sharp edge of the intercondylar box (later modified to a smoother edge) and the femoral component had a prominent "shoulder." In the IB-II the trochlea was deeper to allow for soft tissue clearance. In the MBK the trochlea was more prolonged, with R and L components and the "shoulder" was less prominent. In all the cases the patella was resurfaced with an all polyethylene dome prosthesis. Knees with tibiofemoral problems were excluded. From the data of the present study the following conclusions can be drawn: (a) The most frequent problem was impingement (clunks) with the early version of the IB-I. Smoothening of the anterior edge significantly reduced the incidence of clunks to 5% in the modified IB I. (b) With the IB-II deepening the trochlea for soft tissue clearance improved the degree, not the incidence of clunks (4.5%), compared to the modified IB I. (c) With the MBK clunks were very rare and patellar function improved. (d) Throughout the three series patellar stress fractures and instability were rare and loosening or wear not evident. (e) Normal function (including stairs ascending and descending) can be expected in over 80% of category A patients. (f) Of the various radiological parameters only patella baja was correlated with symptoms in the IB prostheses. (g) We still prefer the dome design because is more tolerant and with cold flow may better conform to the trochlea increasing contact area.

Abstract: Prevention of deep periprosthetic infection requires appreciation of the contributing factors to this phenomenon. The concept of an interdependent relationship between the bacteria, wound and host is most useful when considering the prevention of infections. Establishment of infection depends on the number and virulence of the bacteria, the host's ability to eliminate those bacteria and the status of the wound. Multiple variables contribute to the deposition and proliferation of bacteria into the wound environment which enhance the infectious process, such as the presence of a prosthetic implant or medical conditions and medications which impair the patient's defense. Prevention must address optimization of the wound environment, minimizing the number of bacteria into the wound and augmenting the host defenses. Administration of prophylactic antimicrobials prior to skin incision reduces the incidence of wound infections. The optimal antimicrobial agent should have excellent in vitro activity against staphylococci and streptococci, a long serum half-life, good tissue penetration, be non-toxic and inexpensive.

Abstract: Total knee replacement often is performed with tourniquet application. The advantages of a dry field, including fixation, are well known, but it still is debatable if tourniquet application increases deep vein thrombosis. Measurement of coagulation markers is a well accepted method of studying thrombogenesis activation intraoperatively and postoperatively. Twenty patients undergoing total knee replacement with subarachnoid anesthesia were assigned randomly to two groups: either with tourniquet application (Group I) or without tourniquet application (Group II). There were no differences between patients in the two groups in terms of age, gender, diagnosis (all had osteoarthritis), operative time, and total (intraoperative and postoperative) blood loss. Markers for thrombin generation and fibrinolysis were measured. Blood samples were drawn at four times: baseline before the operation; after bone cuts; after cement fixation (Group II) or 2 minutes after tourniquet deflation (Group I); and 1 hour after surgery. Markers of thrombin generation and fibrinolysis showed a significant increase from baseline in all the patients. In Group II these markers started to increase during surgery, whereas in Group I the increase occurred at the end of the procedure when the tourniquet was deflated. The total amount of thrombin generation was significantly higher in Group II (without tourniquet), whereas fibrinolysis was significantly greater in Group I. Total knee replacement is accompanied by a hypercoagulative state with or without the use of a tourniquet, but it seems to be higher when the tourniquet is not used. In addition, tourniquet application may increase fibrinolysis.

Abstract: The increased risk for deep vein thrombosis (DVT) after orthopaedic surgery has been well documented as well as hypercoagulable state during both total hip arthroplasty (THA) and total knee replacement (TKR). To investigate the influence of the surgical procedure [posterolateral (PL) or lateral (L) approach for THA, use of tourniquet (TQ) or not use of TQ for TKR] on the hypercoagulability and the role of extrinsic pathway activation and endothelial stimulation during orthopaedic surgery we have examined 40 patients (20 patients undergoing primary THA--10 with PL approach and 10 with L approach--and 20 patients undergoing TKR--10 with TQ application and 10 without TQ). Thrombin-antithrombin complexes (TAT), tissue factor (TF), tissue factor pathway inhibitor (TFPI), thrombomodulin (TM) and von Willebrand factor antigen (vWF:Ag) were analyzed before and during the orthopaedic surgery. During THA, TAT plasma levels increased more markedly in patients assigned to the L than PL approach (p <0.05); during TKR an elevation of TAT of higher degree (p <0.05) was observed when TQ was not applicated. Blood clotting activation was significantly (p <0.001) more relevant during THA than TKR. No changes in TF and vWF:Ag plasma levels were observed in all patients undergoing THA and TKR. TFPI plasma levels significantly (p <0.05) decreased 1 h after the end of the THA in group PL and group L, whereas they remained unaffected in the two groups of patients undergoing TKR. Similarly TM plasma levels significantly decreased during THA, but not during TKR. In conclusion, these results show that: 1) the site of surgical procedures and the type of approach affect the degree of hypercoagulability, 2) the blood clotting activation takes place in the early phases of orthopaedic surgery, without signs of extrinsic pathway and endothelial activation.