Pre-operative flexion contracture determines the functional outcome of haemophilic arthropathy treated with total knee arthroplasty

End-stage haemophiliac arthropathy can be successfully treated with total knee arthroplasty. However, the functional results may not be as good as anticipated and certain pre-op knee characteristics may alter the functional results. The purpose of this study was to evaluate the functional outcome of TKA in haemophilic patients with specific attention to final range of motion and residual flexion contracture of the joint. Twenty-one consecutive patients were retrospectively reviewed. The average age was 34 years with an average follow-up of 5.7 years. Functional status was evaluated with Hospital for Special Surgery Knee Score. Receiving Operating Characteristics analysis was used to determine the threshold of pre-operative flexion contracture degree to avoid residual knee contracture. The range of motion was increased in 16 joints and unchanged in three joints and decreased in the remaining two. Preoperative average range of motion was 37.6°, improved to 57.1° post-operatively. The average knee score increased from 27.85 (15-30) points pre-operatively to 79.42 (12-94) points at the last follow-up. The degree of pre-operative flexion contracture was found to be a good predictor for residual flexion contracture. (Specificity: 85.7%, sensitivity: 100%, cut-off: 27.5°). Total knee replacement improves the quality of life in patients with advanced haemophilic arthropathy. Statistical analysis revealed that pre-op flexion contracture of 27.5° is an important threshold. Patients should be operated before that stage to gain maximum benefit with minimal gait abnormalities.     

Computer‐navigated total knee arthroplasty in haemophilic arthropathy

Total knee arthroplasty (TKA) in end‐stage haemophilic arthropathy is complex and challenging due to the altered bony anatomy, arthrofibrosis and muscle contractures. Computer navigation is especially advocated in patients with deformity or altered anatomy to improve alignment and to assist in ligament balancing. The objective of this study was to evaluate the results of computer‐navigated TKA in haemophilic arthropathy. A consecutive series of computer‐assisted TKA for the end‐stage haemophilic arthropathy between February 2007 and December 2009 were evaluated. A total of 27 TKA were performed in 25 patients. Pre‐ and postoperative full‐length weight‐bearing radiographs were assessed for the axial limb alignment. The orientation of the components was measured on anteroposterior radiographs. Clinically, Knee Society score and Short Form‐36 were evaluated. The mechanical axis of the leg was within a range of ±3° varus/valgus in 92% of the TKA. The coronal alignment of the femoral and tibial components was within a range of ±3 degrees in 96% of the knees. The clinical outcomes were significantly improved after the operation. There were no complications specific to the computer navigation. Computer‐navigated TKA helps in restoring the mechanical axis and improves accuracy of orientation of the components in patients with end‐stage haemophilic arthropathy. Potential benefits in long‐term outcome require further investigation.     

In‐patient rehabilitation in haemophilic subjects with total knee arthroplasty

Summary. Total knee arthroplasty (TKA) is a major orthopaedic surgery intervention, indicated for severe haemophilic arthropathy. The aim of our study was to analyse rehabilitation outcome in haemophilic patients after TKA. A consecutive series of 21 patients (23 knees) was retrospectively evaluated. The mean age was 37 ± 8 years (range 22–55). Physiotherapy treatment was performed twice a day for 5 days week^?1, for 3 h day^?1. Assessment included knee range of motion (ROM), Visual Analogue Scale (VAS) for pain evaluation, Western Ontario and McMaster University (WOMAC) Score for functional outcome, Medical Research Council Scale (MRC) for quadriceps muscle strength evaluation, incidence of adverse events and a self‐reported questionnaire. The patients’data were recorded before surgery (t0), at Rehabilitation Unit admission (t1), before discharge (t2) and at follow‐up (t3), 11–48 months after rehabilitation. Western Ontario and McMaster University Score (ref. score: 0–96) was 56.7 ± 12 at t0 and 6.2 ± 6 at t3 (t3 vs. t0: P < 0.001). Visual Analogue Scale (ref. score: 0–10) decreased from 5.0 ± 2 at t1 to 2.1 ± 2 at t2 (t2 vs. t1: P < 0.05) and to 0.1 ± 0 at t3 (t3 vs. t2: P < 0.05). Flexion degrees increased from 43.4 ± 21° at t1 to 80.2 ± 15° at t2 (t2 vs. t1: P < 0.001) and to 95.0 ± 15° at t3 (t3 vs t2: P < 0.05). According to MRC (ref. score: 0–5), quadriceps muscle strength increased from 2.3 ± 0.6 at t1 to 3.6 ± 0.5 at t2 (t2 vs. t1: P < 0.05). Adverse events were found in four patients. Patients’ satisfaction on their outcome at follow‐up was referred as good by 72% of patients or excellent by 28% of patients. Postsurgical intensive rehabilitation in haemophilic patients resulted effective, safe and feasible.     

Repair of partial patellar ligament avulsion during total knee arthroplasty using the Statak device

 The Statak is a suture anchor device used for attaching soft tissue to bone. This is a report on six knees in which this device was used to repair partial avulsion of the patellar ligament during total knee arthroplasty (TKA). The six patients were all women. The average age of the patients was 69 years. The diagnosis was osteoarthritis in three patients, rheumatoid arthritis in two, and steroid arthropathy in one. Three of the operations were revision arthroplasties. In all six cases, approximately half of the patellar ligaments were accidentally detached from the tibial tubercles during surgery, and were repaired using the Statak devices. The average length of follow-up was 3 years. The Knee Society knee score improved from an average of 15 points preoperatively to 87 points at the latest follow-up. The average total range of motion measured 104° before surgery and 108° at the latest follow-up. Three of the six knees operated on had no extensor lag. The suture anchor simplifies the secure fixation of the ligament to bone. The procedure can be performed easily and quickly. In our opinion, the Statak device has proven itself to be effective for the repair of partial patellar ligament avulsion during TKA. Received: December 14, 2001 / Accepted: March 26, 2002 Correspondence to: K. Yamada     

Functional kinesiology in haemophilia, an area yet to be explored

Summary. In haemophilic arthropathy there is a progressive limitation of the range of motion (ROM) which may lead to disabilities in the activities of daily living (ADL). In the literature the pathology of haemophilic arthropathy is described extensively, but only one paper describing functional limitations caused by limited range of motion (LOM) in haemophilia was found. The aim of the pilot study was to estimate on theoretical grounds, how many patients with haemophilia might suffer from functional disabilities. Material: ROM of elbows, knees and ankles of 155 Haemophilia A and B patients. Methods: flexion and extension were measured with an ordinary goniometer. The ROM of joints of patients with haemophilia was compared with normal values. Results: 39 of 155 patients had a normal ROM in both elbows; 22 in one elbow; 34 patients had disabilities in ADL with both arms; 14 with one arm; 18 were able to compensate; 89 had no problems; 79 of 155 patients had a near normal ROM of both knees; 38 patients could not ride an ordinary bicycle. Conclusion: only limited data are available concerning the normal ROM needed for individual ADL. Until additional data are available, it is not possible to predict which patients will be disabled in their activities of daily living and individual counselling should be done during the yearly outpatient comprehensive care clinics. Conservative and surgical measures should be taken to ensure elbow flexion of at least 120° and knee flexion of 100° for Western societies. In Asian countries patients with haemophilia need maximum knee flexion and ankle dorsi flexion.     

Preliminary results for the use of knee mega‐endoprosthesis in the treatment of musculoskeletal complications of haemophilia

Complications of haemophilia in the knee region are rare and difficult to treat. Use of surgical treatments such as total knee arthroplasty cannot satisfactorily restore knee function in patients with these complications, which include massive haemophilic pseudotumour, fracture around the knee and haemarthrosis. To analyse the postoperative results of patients suffering from complications of haemophilia and treated with a knee mega‐endoprosthesis, to discuss and compare this type of surgical management with other types of treatments used in similar cases. We retrospectively analyse the surgical results of patients who were treated with a knee mega‐endoprosthesis for complications of haemophilia. Three severe haemophilic arthritic knees, of which two were combined with femoral condylar fractures, were treated in a one‐stage surgery, and another two knees which presented with massive haemophilic pseudotumours and bony defects were treated in a two‐stage operation. Mean age at time of surgery was 28.5 years old and mean follow‐up time was 22.8 months; the mega‐endoprosthesis surgery was successfully performed in four cases and the mean range of motion increased from 29.5° preoperatively to 96.75° postoperatively. The Knee society score function score value increased from 25 to 82.5. One knee was amputated because of uncontrollable recurrent haemorrhage. Roentgenograms did not show any signs of loosening of the prostheses. Use of Mega‐endoprosthesis in the treatment of complications of haemophilia can offer patients suffering from massive pseudotumours with bone defect, severe contracture knee haemophilic arthritis and fractures around a haemophilic knee a viable treatment option.     

Knee flexion contracture in haemophilia: treatment with circular external fixator

Haemophilia, a bleeding disorder, causes recurrent intra‐articular bleeding of the joints result‐ing in chronic haemophilic arthropathy with fixed knee flexion deformity. Mid‐long‐term results (between 2002 and 2006) of deformity correction in haemophilic patients with Ilizarov type circular external fixators were retrospectively evaluated. There were six patients (five haemophilia A and one haemophilia B). The mean age was 14.7 years (range, 8–22 years) at the time of initial surgery. The mean knee flexion contracture was 45 degrees (range, 30–75 degrees). The mean arc of motion was 58.3 degrees (range, 40–100) before the surgery. The mean duration of follow‐up was 8 years (range, 5.5–10 years). The mean duration of external fixation was 4.4 months (range, 2.5–10.5 months). Full extension of the knee joint was obtained in all patients in the early postoperative period. No bleeding, neurological or vascular complications were encountered. The mean amount of recurrence in knee flexion contracture was 10 degrees (range, 0–15 degrees). The amount of the correction was significant (P = 0.0012) and the mean arc of motion was 51.6 degrees (range, 25–90 degrees) that show a decrease of 6.7 degrees (P = 0.04) at the end of follow‐up. The circular external fixator is an important, safe and less invasive alternative surgical treatment modality with low recurrence rate. Using the external hinges and distraction during the correction has a protective effect on the joint. It requires a team‐work consisting of a haematologist, an orthopaedic surgeon and a physical therapist.     

Cementless total hip arthroplasty for haemophilic arthropathy: follow‐up result of more than 10 years

The improvement of prophylaxis and adequate replacement of clotting factors, the quality of life and natural history of haemophilia have been significantly improved. However, significant functional impairment is inevitable. This study was performed to evaluate over 10 years clinical and radiographic outcomes of cementless total hip arthroplasty (THA) for treatment of haemophilic hip arthropathy. Between 1995 and 2003, 27cases of cementless total hip arthroplasties were performed in 23 haemophilic patients. A total of 21 cases from 17 patients were available for follow‐up analysis over 10 years. Modified Harris hip score, the range of motion of the hip joint, perioperative coagulation factor requirements and complications associated with bleeding were evaluated as part of the clinical assessment. For the radiographic assessment, fixation of component, osteolysis, loosening and other complications were evaluated. Clinically, the mean Harris hip score improved from 57 points before the operation to 94 points at the last follow‐up. The mean flexion contracture was 10° preoperatively and 0.9° at the final follow‐up. The further flexion improved from 68.4° to 90.5° after surgery. The mean monthly requirement of factor VIII reduced from 3150 units before surgery to 1800 units at the time of the last follow‐up. There were three cases of rebleeding. In one case, a progressive haemophilic pseudotumour was found. Reoperation for any reason including revision was performed in three cases. We believe that cementless THA in patient with haemophilic hip arthropathy can bring reliable pain relief and functional improvement for longer than 10 years.     

Efficacy and safety using autotransfusion system with postoperative shed blood following total knee arthroplasty in haemophilia

The purpose of this study was to evaluate the efficacy and safety of postoperative wound drain salvage and autotransfusion system in haemophilic patients undergoing elective total knee arthroplasty (TKA). No literature exists on reinfusing drained blood in patient with haemophilia undergoing TKA. Eighty‐eight knees of 66 patients received cemented TKA due to end‐stage haemophilic arthropathy (group I; with autotransfusion in 59 knees, group II; without autotransfusion in 29 knees). In group I, the postoperative shed blood was transfused within 6 h after surgery. The amount of blood drainage and reinfused blood, rate and amount of allogenic transfusion, postoperative change of haemoglobin level, prothrombin time (PT) and activated partial thromboplastin time were analysed. The mean postoperative blood drainage was 932 ± 479 mL in group I and 830 ± 492 mL in group II (P > 0.05). The mean volume of blood reinfused was 530 ± 265 mL in group I. Allogenic transfusion was needed in six knees (10.2%) of group I and eight knees (27.6%) of group II (P = 0.036). The mean volume of allogenic transfusion was 480 ± 49 mL in group I and 1041 ± 691 mL in group II (P > 0.05). Changes of all the laboratory results before and after TKA showed no statistically significant difference except PT was prolonged in group I (P = 0.008) at postoperative day 1. Moreover, there was no significant complication related to either reinfusion or allogenic transfusion in both groups . This study showed that reinfusion of drained blood is a simple, safe and efficacious method in patients with haemophilia undergoing TKA.     

Intra-articular hyaluronic acid in the treatment of haemophilic arthropathy of the knee. Clinical, radiological and sonographical assessment

Hyaluronic acid has been used successfully in the treatment of osteoarthritis since 1989. There is no experience in haemophiliacs in larger study groups. In a prospective study, 20 patients (21 knees) with haemophilic arthropathy of the knee received 20 mg hyaluronic acid by intra-articular injection for 5 consecutive weeks. Assessment included clinical scores, X-ray, magnetic resonance imaging (MRI) and biomechanical motion analysis before and 3 months after the first injection. The score of the WFH advisory committee and the Aichroth score for special evaluation of the knee were used. After an average period of 26 months, the World Federation of Hemophilia (WFH) score, the Aichroth score and the visual analogue scale were evaluated again. All patients had pain caused by their arthropathy, nine of them had positive antibodies to human immunodeficiency virus, and 15 had chronic hepatitis C. The mean WFH score was 8.1 points, the Petterson score was 7.3 points and the Aichroth score was 38 points (maximum 55 points). The WFH score decreased to 7.3 points, the Aichroth score improved to 40 points and the subjective assessment measured with a visual analogue scale improved from 5.3 to 3.7 points. No differences from MRI controls were detected. After 3 months, 14 of 20 patients improved subjectively, particularly in longer walking distance, stair-climbing or initial pain. These positive aspects were limited by arthropathy in adjacent joints. After 26 months 10 patients still are benefiting for up to 31 months follow-up. The average WFH score was 7.3 points, the Aichroth score 39 points, the visual analogue scale 4.0 points. We recommend hyaluronic acid for haemophilic arthropathy of the knee when regular conservative therapy has failed and operative treatment is not feasible.     

Three-dimensional limb lengthening after total knee arthroplasty in a simulation study

Abstract

Objectives: Limb lengthening after total knee arthroplasty (TKA) has been reported in some cases, all of which were evaluated using two-dimensional images. To our knowledge, no case has been evaluated using three-dimensional (3D) images. We investigated 3D limb lengthening after TKA.

Methods: We simulated 100 varus knees using 3D templating software. Virtual TKA was performed to maintain the original joint line by conducting a measured-resection technique. We examined the relationships of 3D distance between the femoral head center and ankle center before and after TKA, degree of hip–knee–ankle angle (HKA) improvement, and degree of flexion contracture angle improvement.

Results: All cases showed limb lengthening (average, 9.4?±?6.0?mm). The coefficients of correlation with limb lengthening and the degree of HKA improvement and the degree of flexion contracture angle improvement were good (0.730 and 0.751, respectively). The correlation between the degree of total improvement (the degree of HKA improvement?+?the degree of flexion contracture angle improvement) and limb lengthening was strong (r?=?0.896).

Conclusion: The expected limb lengthening when performing measured-resection TKA is expressed as 0.58?×?(the degree of HKA improvement?+?the degree of flexion contracture angle improvement) mm and is a useful index.     

Non-operative treatment of flexion contracture of the knee in haemophilia

For the non-operative treatment of flexion contracture of the haemophilic knee we have used serial casting and wedging in 58 patients, and extension/de-subluxation orthoses in 13 patients. On average it was possible to achieve -5° of extension by 4 weeks, with only a little improvement in the following 4 weeks. The short-to medium-term results using either the extension/de-subluxation hinges or serial casting were similar. Both methods have been shown to result in significant improvement in joint contracture.     

Clinical outcomes and patient satisfaction following total joint replacement in haemophilia – 23‐year experience in knees,hips and elbows

Summary. Joint replacement surgery is an available option for end‐stage haemophilic arthropathy. However, reports with long‐term follow‐up are limited. Moreover, patient satisfaction in this setting has never been measured. We share our institution’s experience with joint arthroplasty in haemophilic arthropathy and report on clinical outcomes and patient satisfaction. Between 1985 and 2007, 65 consecutive joints in 45 patients (mean age: 48.6; range: 22–83) underwent joint replacement surgery. Of these, 40 total knee replacements in 31 patients, 18 total hip replacements in 16 patients and 6 total elbow replacements in 3 patients were included. Average follow‐up was 10.7 years (2.4–24.3). Charts were reviewed retrospectively and patients were asked to return for clinical assessment and completion of questionnaires. According to the Knee Society clinical score, postoperative results were good to excellent in 83% of knees. According to the Harris Hip Score, results were good to excellent in 31% of hips. According to the Mayo Elbow Performance Score, results were good to excellent in 83% of elbows. Complication rates are higher than in the non‐haemophilic population, while prosthesis survival rates are lower. Patient satisfaction with pain relief is higher than satisfaction with functional improvement. For 88% of joints, patients are willing to have the same operation again. This study confirms previous knowledge on the role of total joint arthroplasty in haemophilic arthropathy. Despite high complication rates and modest functional outcomes, the operations are valuable for achieving pain relief. In general, patients find that risks are outweighed by the benefits.     

Total ankle replacement in patients with haemophilia and virus infections – a safe alternative to ankle arthrodesis?

Despite reliable results of ankle fusion for advanced haemophilic arthropathy, total ankle replacement (TAR) may be functionally advantageous. There is only very limited literature data available on TAR in patients with haemophilia. The objective of this study is to evaluate the short‐ and mid‐term results after TAR in patients with end‐stage haemophilic ankle arthropathy and concomitant virus infections. In a retrospective study, results after eleven TAR in 10 patients with severe (n = 8) and moderate (n = 2) haemophilia (mean age: 49 ± 7 years, range, 37–59) were evaluated at a mean follow‐up of 3.0 years (range, 1.2–5.4). Nine patients were positive for hepatitis C, five were HIV‐positive. Range of motion (ROM), AOFAS‐hindfoot‐score, pain status (visual analogue scale, VAS) as well as patient satisfaction were evaluated. In two cases deep prosthesis infection occurred leading to the removal of the implant. In the remaining eight patients the mean AOFAS score improved significantly from 21.5 to 68.0 points (P < 0.0005), the VAS score decreased significantly from 7.6 to 1.9 points (P < 0.0005). ROM increased from 23.2 to 25.0 degrees (P = 0.51). At final follow‐up all patients without any complications were satisfied with the postoperative results. Radiographic examination did not reveal any signs of prosthetic loosening. TAR is a viable surgical treatment option in patients with end‐stage ankle osteoarthritis due to haemophilia. It provides significant pain relieve and high patient satisfaction. However, due to the increased risk of infection and lack of long‐term results, TAR particularly in patients with severe haemophilia and virus infections should be indicated carefully.     

Comparison of clinical and radiographic results between total knee arthroplasties using medial pivot and posterior-stabilized prosthesis: A meta-analysis

Objective:To evaluate the clinical and radiographic outcomes of total knee arthroplasties (TKA) between using medial-pivot (MP) and posterior-stabilized (PS) prosthesis. Does MP prosthesis and PS prosthesis influence the clinical results of a TKA?Methods:An electronic literature search of PubMed Medline and the Cochrane Library was performed from inception to October 1, 2019. A meta-analysis to compare postoperative outcomes of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Knee Society Score (KSS), range of motion (ROM), complications, and radiographic results between MP and PS prosthesis were conducted.Results:Seven eligible studies involving 934 adult patients (MP group, n = 461; PS group, n = 473) were identified for analysis. This study showed no significant difference between the 2 groups in the WOMAC scores, KSS, ROM, and complications (P > .05). The differences of the femorotibial angle, position of implant, and patellar tilt were also not significant between the 2 groups (P > .05).Conclusion:The present meta-analysis has shown that patients with the MP prosthesis have similar clinical results as patients with PS prosthesis. Furthermore, the radiographic results, especially patella tilt angle, were also similar between the 2 groups. Therefore, surgeons should be aware that the types of prostheses are not a decisive factor to ensure successful operation.     

Diagnostic accuracy of range of motion measurements in early symptomatic hip and/or knee osteoarthritis

Objective

To examine the diagnostic accuracy of hip internal rotation, hip flexion, and knee flexion measurements for the presence of osteophytosis and joint space narrowing (JSN) in early symptomatic osteoarthritis (OA).

Methods

The baseline data for 598 participants of the Cohort Hip & Cohort Knee study were used. Participants underwent a standardized physical and radiographic examination. The active range of motion (ROM) was assessed using a goniometer. The ROM cutoff with the highest discriminative ability for radiographic features of OA was defined by maximizing the sum of the sensitivity and specificity. Several diagnostic measures were calculated to establish the diagnostic accuracy of ROM measurements for the presence of radiographic features.

Results

In patients with hip symptoms, hip internal rotation <24° and flexion <114° were found to be the cutoffs with the highest discriminative ability to distinguish between patients with and without radiographic features. In patients with knee symptoms, knee flexion <132° was the cutoff with the highest discriminative ability. The American College of Rheumatology (ACR) criterion of hip internal rotation <15° increased the probability of the presence of osteophytosis or JSN from 25% to 58%. The diagnostic accuracy of hip and knee flexion measurements was low.

Conclusion

To reduce the number of patients that are not identified by the ACR criterion of hip internal rotation <15°, it is recommended to change the cutoff to internal rotation <24° in patients with early symptomatic OA. Individual hip and knee flexion measurements seem to be of little diagnostic value in early symptomatic OA.     

Haemophilic; Arthropathy: Assessment of Quality of Life After Total Knee Arthroplasty

The goal of this study was to examine how the known effects of total knee arthroplasty (TKA) on clinical outcome parameters translate into improved quality of life, as measured with validated condition-specific and generic questionnaires (Knee Society Score, WOMAC, SF-12, transition questions), addressing physical, mental and social health. Eleven patients (13 knees) undergoing TKA from 1986 to 1994, with the diagnosis of severe haemophilic arthropathy of the knee, were followed-up over a 4-year period on average. TKA was found to reduce the burden of disease to levels similar to patients with osteoarthritis undergoing hip arthroplasty. Clinical and functional improvement after TKA translated into a substantial and significant increase in quality of life and patient satisfaction, found in objective as well as in patient-perceived measures. However, the physical functional ability did not reach the same level as in the corresponding population not affected by haemophilia, due to residual symptoms and impairment of other joints. Received: 30 September 1998 / Accepted: 17 March 1999     

Correction of fixed contractures during total knee arthroplasty in haemophiliacs

Encouraging clinical experience has increased the indications for prosthetic knee arthroplasty in haemophiliacs. The medical status, physical disability, age and projected activity levels are the major factors in determining treatment for the patient with unilateral or bilateral haemophilic arthropathy of the knee. In more severely involved knees of patients with haemophilia, flexion contracture is a common deformity. In addition, valgus, external rotation deformity and posterior subluxation of the tibia may exist. The surgeon must have the expertise and experience to correct these deformities sufficiently when performing a total knee arthroplasty. A properly performed soft-tissue release which achieves balance between the medial and lateral ligamentous structures and posterior capsule can provide stability to the knee with a semiconstrained prosthesis. In cases with severe deformity requiring resection of the posterior cruciate ligament a posterior cruciate substituting prosthesis may be necessary.     

Preoperative quadriceps strength predicts functional ability one year after total knee arthroplasty

OBJECTIVE: Quadriceps weakness is common after total knee arthroplasty (TKA) as is longterm disability. We hypothesized that preoperative quadriceps strength would be the best predictor of postoperative functional ability when compared to preoperative pain or knee range of motion (ROM). METHODS: Forty subjects (mean age 63 +/- 8 yrs, body mass index 29.4 kg/m2 +/- 4.2) were tested 2 weeks before and one year after TKA. Quadriceps strength was measured isometrically, pain was quantified using the Medical Outcome Study Short-Form 36 (SF-36) bodily pain subset, and knee flexion range of motion (ROM) was assessed by goniometer. Performance based functional assessment included the Timed Up and Go test (TUG) and a timed Stair Climbing Test (SCT). The Knee Outcome Survey (KOS) and the SF-36 questionnaires were used to quantify perceived function. The ability of preoperative factors to predict postoperative outcomes was analyzed using hierarchical regression. Differences in means before and one year after surgery were analyzed using paired t tests. RESULTS: Significant improvements were found in all functional measures assessed (p < 0.001). Preoperative quadriceps strength accounted for the bulk of the variance in the one-year SCT and the TUG (p < 0.001), but did not achieve significance in predicting one-year questionnaire scores (p > 0.05). Neither preoperative pain nor knee ROM were significant predictors of any functional measure (p > 0.05). CONCLUSION: Preoperative quadriceps strength plays a dominant role in predicting one-year SCT and TUG functional measures, but it is not a good predictor of score on self-report questionnaires. Preoperative bodily pain and knee flexion ROM are poor predictors of all functional outcome measures.