Mean Knee Society Pain Research Articles

Comparison of Posterior Cruciate-Retaining and High-Flexion Cruciate-Retaining Total Knee Arthroplasty Design

BackgroundHigh-flexion prostheses have been developed to achieve deep flexion after total knee arthroplasty. The purpose of this study is to compare standard NexGen (CR, cruciate-retaining) and high-flexion NexGen (CR-flex) total knee prostheses in terms of range of motion, clinical and radiologic outcomes, rates of complications, and survivorship in long-term follow-up. MethodsFrom January 2000 to December 2008, 423 consecutive knees underwent total knee arthroplasty using standard CR or CR-flex prostheses. Fifty-three patients were lost to follow-up or declined to participate and 54 died, leaving 290 knees. The minimum duration of follow-up was 8 years (mean 10.1 years). Physical examination and knee scoring of patients were assessed preoperatively, at 6 months and 1 year after surgery, and annually thereafter. Supine anteroposterior and lateral radiographs and standing anteroposterior hip-to-ankle radiographs were obtained preoperatively and at each follow-up. ResultsMean postoperative range of motions in the standard CR group and the CR-flex group were similar, showing no significant difference between the 2 groups (P = .853). At the time of the final follow-up, mean total Hospital for Special Surgery scores were similar between the 2 groups (P = .118). Mean Knee Society pain (P = .325) and function scores (P = .659) were also comparable between the 2 groups. Western Ontario and McMaster Universities Osteoarthritis Index score showed no intergroup difference either (P = .586). The mean hip-knee-ankle angle at the final follow-up was approximately the same (P = .940). Mean coronal angles of femoral and tibial component at final follow-up were also similar (P = .211 and P = .764, respectively). The prevalence of the radiolucent line was 0.6% in the standard CR group and 0.9% in the CR-flex group. Estimated survival rate according to Kaplan-Meier survival analysis was 97.2% in the standard CR group and 95.6% in the CR-flex group at mean follow-up of 10.1 years. ConclusionThis study suggests that excellent clinical and radiographic outcomes could be achieved with both standard and high-flexion CR total knee designs. High-flexion CR prosthesis did not show any advantages over the standard design.

Outcomes of a newer-generation cementless total knee arthroplasty design in patients less than 50 years of age.

Younger patients undergoing cemented total knee arthroplasty (TKA) may be at risk for lower implant survivorship and higher revision rates due to the historical increased prevalence of aseptic loosening and instability in this cohort. The recent advances of cementless TKAs may mitigate some of these complications. However, there is a paucity of studies reporting on patients who are under 50 years who have undergone a cementless TKA. Therefore, this study evaluated: (I) implant survivorship; (II) functional outcomes and complications; and (III) radiographic outcomes in patients who were less than 50 years of age and underwent cementless TKA. A total of 29 patients (31 knees) younger than 50 years who underwent primary TKA at a single institution (Mount Sinai Beth Israel, New York, New York, USA) from June 2008 to May 2014 were included. Their mean follow-up was 4 years (range, 2 to 6 years). The cohort included 20 women and 9 men who had a mean age of 45 years (range, 34 to 49 years), and a mean body mass index (BMI) of 33 kg/m2 (range, 22 to 54 kg/m2). The preoperative knee diagnoses were osteoarthritis (n=24), osteonecrosis (n=5), and rheumatoid arthritis (n=2). A Kaplan-Meier analysis was used to calculate the all cause implant survivorship. Functional outcomes and all complications were recorded for each patient. Additionally, radiographic evaluation using the new Knee Society Radiographic Evaluation and Scoring System was performed. The overall implant survivorship was 100%; there were no failures or revision surgeries performed as of the latest follow-up visit. At the latest follow-up, the mean Knee Society pain score was 92 points (range, 80 to 95 points) and the mean Knee Society function score was 84 points (range, 70 to 90 points). Additionally, the mean knee extension was 1 degree (range, 0 to 5 degrees) and the mean knee flexion was 125 degrees (range, 95 to 140 degrees). Furthermore, at the latest follow-up, on radiographic evaluation, there was no evidence of component loosening, subsidence, radiolucency, gap formation, or reactive changes, and there were no postoperative complications. Cementless fixation of TKAs had excellent survivorship and functional and radiographic outcomes at midterm follow-up in patients younger than 50 years. Although longer follow-up is needed, these cementless TKA implants appear to provide promising results in younger patient populations.

Cementless Posteriorly Stabilized Total Knee Arthroplasty: Seven-Year Minimum Follow-Up Report

BackgroundThe purpose of this study is to evaluate (1) implant survivorship; (2) patient outcomes; (3) complications; and to (4) perform a radiographic analysis of cementless posteriorly stabilized total knee arthroplasty (TKA) patients at a minimum of 7-year follow-up. MethodsOur original cohort was composed of 114 consecutive cementless posteriorly stabilized total knee arthroplasties (110 patients) performed by a single surgeon between 2008 and 2010. Since our original report, 4 (1 bilateral) patients died and 2 were lost to follow-up. Therefore, there were 104 patients who had 107 knees available for final follow-up. The final cohort included 43 men and 61 women, who had a mean age of 69 years (range 47-87) and were followed from 7 to 9 years (mean 8 years). Patient outcomes and complications were obtained from electronic medical records. Radiographic assessment was done using the Knee Society Radiographic Evaluation System. ResultsThe all-cause survivorship was 98% (95% confidence interval 1.01-0.96). Since the original report, there has been 1 post-traumatic loosening of the tibial baseplate, and 1 revision for instability. There were no femoral revisions or patella revisions. The mean Knee Society pain score was 93 points (range 80-100) and the function score was 78 points (range 68-95). Excluding revisions, there was no evidence of progressive loosening of any implant components. ConclusionBased on these 7-year minimum follow-ups, femoral, tibial, and patellar cementless hydroxylapatite-coated beaded implants perform well at up to 9 years postoperatively and offer surgeons and patients a cementless option that may provide long-lasting biological fixation.

Cementless Total Knee Arthroplasty in Patients Older Than 75 Years.

Some surgeons have been hesitant to use cementless fixation for total knee arthroplasty (TKA) in elderly patients due to concerns regarding successful bone biological fixation. Therefore, this study evaluated: (1) implant survivorship, (2) functional outcomes, (3) radiographic outcomes, and (4) complications in patients over 75 years of age who underwent cementless total knee arthroplasty. A total of 134 patients (142 TKAs) older than 75 years at a single institution between June 2008 and June 2014 were retrospectively reviewed. Their mean follow-up was 4 years (range: 2-8 years). The cohort consisted of 91 women and 43 men who had a mean age of 80 years (range: 76 to 88 years). The preoperative diagnoses were osteoarthritis (n = 107 patients), rheumatoid arthritis (n = 21 patients), and osteonecrosis (n = 6 patients). Descriptive statistics were used to calculate the means and ranges and a Kaplan-Meier analysis was performed to determine the aseptic and all cause implant survivorship. Radiographic evaluation was performed using the new Knee Society Radiographic Evaluation and Scoring System. Functional outcomes at the final follow-up as well as all medical and surgical complications were recorded for each patient. The aseptic implant survivorship was 99.3% (95% CI: 7.9-8.1), and the all cause implant survivorship was 98.6% (95% CI: 7.9-8.1). There was one aseptic revision and one septic revision. At the latest follow-up the mean Knee Society pain score was 93 points (range, 80-100 points), and the mean Knee Society function score was 84 points (range, 70-90 points). On radiographic evaluation, there were no progressive radiolucencies, subsidence, and loosening of prostheses at the latest follow-up. The use of cementless TKA demonstrated excellent survivorship, mid-term clinical and functional outcomes, as well as no progressive radiolucencies or subsidence in patients older than 75 years. In addition, there was a low rate of surgical and medical complications. Therefore, cementless TKA may be a good option for patients older than 75 years.

Reconstruction of the patellar tendon using a Y-shaped flap folded back from the vastus lateralis fascia

BackgroundNeglected and repeated ruptures of the patellar tendon are fortunately an uncommon event. These ruptures are often difficult to repair because they are generally accompanied by contractures of the quadriceps muscle and extensive scar tissue formation, and clinical findings are similar regardless of whether the rupture occurred during or after total knee arthroplasty. In both cases, reconstruction is the treatment. MethodsHere, we present data on reconstruction of the patellar tendon using our own method, which is performed in the following manner: the fascia flap shafted in the distal direction is separated from the vastus lateralis fascia of the quadriceps muscle, then folded back and fixed to the tibial tuberosity enclosing the patella in a Y shape. We used this new method in sixteen cases. All of the patients were examined clinically for an average of twenty-eight months. The Knee Society score was determined prior to surgery and on follow up. ResultsBoth the physical and ultrasound monitoring showed that all sixteen tendons healed properly, indicating that there was no need for any further surgical interventions. The mean Knee Society pain and function scores as well as the average range of motion of the knee increased significantly after the operations. ConclusionWe believe that the presented method is an acceptable option for functional and biomechanical repair of the patellar tendon for the following reasons: the static balance of the knee joint remains unaltered, the quadriceps muscle is not damaged, and the central pulling direction remains steady.

Can Tantalum Cones Provide Fixation in Complex Revision Knee Arthroplasty?

The best method for managing large bone defects during revision knee arthroplasty is unknown. Metaphyseal fixation using porous tantalum cones has been proposed for severe bone loss. Whether this approach achieves osseointegration with low complication rates is unclear. We therefore asked: (1) What is the risk of infection in revision knee arthroplasty with large bone defects reconstructed with porous tantalum cones? (2) What is the rate of osseointegration with these cones? (3) What is the rate of loosening and reoperation? (4) Is knee function restored? We retrospectively reviewed 27 patients who had 33 tantalum cones (nine femoral, 24 tibial) implanted during 27 revision knee arthroplasties. There were 14 women and 13 men with a mean age of 64.6 years. Preoperative diagnosis was reimplantation for infection in 13 knees, aseptic loosening in 10, and wear-osteolysis in four. Patients were evaluated clinically and radiographically using the score systems of the Knee Society and followed for a minimum of 2 years (mean, 3.3 years; range, 2-5.7 years). One knee with two cones was removed for infection. All but one cone showed osseointegration. One knee was revised for femoral cone and component loosening. There was one reoperation for femoral shaft fracture and one for superficial dehiscence. The mean Knee Society pain score improved from 40 points preoperatively to 79 points postoperatively. The mean function score improved from 19 points to 47 points. Our observations suggest metaphyseal fixation with tantalum cones can be achieved. Longer-term followup is required to determine whether the fixation is durable.

Modified Hybrid Stem Fixation in Revision TKA is Durable at 2 to 10 Years

Hybrid revision knee component fixation, in which cement is placed in the metaphysis combined with a cementless diaphyseal engaging stem, provides ease of insertion, possibly improved component alignment, and easier removal if required, compared with fully cemented prostheses. The literature suggests the technique has a 2 to 5 year survivorship ranging from 81% to 94%. To confirm the literature we asked whether (1) a modified hybrid fixation technique is durable and reliable at an average 5-year followup, (2) this method of fixation provides clinical improvements as assessed by knee scores, (3) there are radiographic findings unique to this fixation technique, (4) the degree of knee constraint influences clinical performance or radiographic findings, and (5) end-of-stem pain is associated with this fixation method? We retrospectively reviewed all 83 patients who had 88 both-component revision TKAs using our modified hybrid fixation technique. We assessed the Knee Society scores and evaluated radiographs for radiolucent and radiosclerotic lines. The minimum followup was 24months (average, 65months; range, 24-126months). Kaplan-Meier survivorship free of aseptic loosening was 100% at 5years and 90% at 10years. Postoperatively, the mean Knee Society pain and function scores both improved. Partial radiolucent lines were rare; two components were loose. We commonly observed radiosclerotic lines adjacent to stem extensions but these did not affect clinical scores or implant stability at last followup. Neither knee scores nor radiographic findings differed based on knee constraint. End-of-stem pain occurred rarely and was transient. Modified hybrid fixation of revision knee arthroplasty using a diaphyseal engaging stem and cementation only in the metaphysis is durable at a mean 5years followup. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Hip and Knee Arthroplasty in Hypophosphatemic Rickets

There is very limited published information about the technical aspects and durability of lower extremity arthroplasty in hypophosphatemic rickets. Between 1972 and 2006, 8 total hip arthroplasties (THAs) and 6 total knee arthroplasties (TKAs) were performed in 8 patients with degenerative arthritis and bone deformity secondary to hypophosphatemic rickets. Two hips required osteotomies at the time of arthroplasty, and 1 TKA patient required postoperative osteotomies. Specialized implants were required in 3 hips and 1 knee. At average follow-up of 7 years, mean Harris hip scores improved to 21 points, and mean Knee Society pain and function scores improved to 48 points and 27 points, respectively. One cemented THA failed due to femoral aseptic loosening at 13 years postoperatively; all other implants remained well fixed. Lower extremity arthroplasty is effective and durable for patients with arthritis associated with hypophosphatemic rickets, but corrective osteotomies and use of special implants should be anticipated with more severe deformities.

Navigation Did Not Improve the Precision of Minimally Invasive Knee Arthroplasty

Potential advantages of minimally invasive total knee arthroplasty (TKA) include decreased pain, faster recovery, and increased quadriceps muscle strength. Computer-assisted navigation has been associated with more accurate component alignment. We evaluated two groups of 50 patients who had minimally invasive TKAs performed with and without navigation by two surgeons. A comparison of 50 previous TKAs by each of the two surgeons showed similar results. The mean operative times for the navigation and nonnavigation groups were 112 minutes (range, 63-297 minutes) and 54 minutes (range, 35-86 minutes), respectively. The mean estimated blood losses, mean Knee Society pain as well as functional scores and mean component alignments were similar. The number of knees that deviated by more than 3 degrees from the normal anatomic axis was three and one in the navigated and nonnavigated groups, respectively. Complication rates were 6% and 4% in the navigated and nonnavigated groups, respectively. Our data demonstrate no distinct advantage of navigation when combined with a minimally invasive approach. Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Outcome of Unicompartmental Knee Arthroplasty in Patients Receiving Worker's Compensation

Nineteen patients with a worker's compensation board (WCB) claim treated by unicompartmental knee arthroplasty for medial compartment osteoarthritis were compared to 20 patients who had no WCB claim. In WCB patients, the mean Knee Society Score (KSS) improved from 47.4 to 76.9; the mean Knee Society function score, from 43.8 to 75; and the mean Knee society pain score, from 6.9 to 29.4. In non-WCB patients, the mean KSS improved from 43.3 to 90.7; the mean Knee Society function score, from 44.7 to 90; and the mean Knee Society pain score, from 3.6 to 41.7. The difference in improvement of KSS between the two groups was significant ( P = .008). The postoperative KSS in the non-WCB patients was significantly higher than that of the WCB group ( P = .007). There was no difference between the incidences of conversion to total knee arthroplasty.

Triathlon Total Knee Arthroplasty –4-Year Outcomes with a High-Performance Implant

The 4-year outcomes of a prospective study of patients undergoing Triathlon total knee arthroplasty (TKA) are presented. There were 2035 consecutive cemented TKAs performed on 1688 patients. Mean follow-up was 21 months, including 713 knees with a follow-up of > or =2 years. In a subgroup of 239 patients, the coverage of the patella cut surface by the patella component was analyzed. To our knowledge, this is the first article to study this issue. Mean Knee Society pain scores improved from 48 to 96, function improved from 63 to 85, and range of motion improved from a mean of -5 degrees to 104 degrees to a mean of -2 degrees to 126 degrees. Coverage of the patella by the prosthesis was full from medial to lateral in 88% and full from proximal to distal in 91% of knees. The implant system has performed well within the follow-up period, with no implant- or design-related failures.

Cementless Fixation in Revision Total Knee Arthroplasty

A surgical approach to revision total knee arthroplasty that includes minimal bone resection, minimal soft-tissue stripping, cementless fixation of the femoral and tibial components, and morselized allografting of defects was used and evaluated in 105 patients (110 knees) with severe bone loss. The patients were followed for 60 to 127 months postoperatively. Fixation included a tightly-fit fluted titanium stem in the femoral and tibial canals and rim contact on the peripheral rim of the tibia. One tibia loosened and one knee failed because of infection. Ligamentous stability and pain relief were consistent through the followup period. At 10 years the mean valgus laxity was 4 degrees +/- 2.5 degrees, and the mean varus laxity was 5.2 degrees +/- 3.3 degrees. Mean Knee Society pain score was 47 +/- 2.1. Pain was mild in 28 knees, moderate in eight knees, and severe in two knees. Evidence of bone healing occurred in the bone defects that could be seen on radiographs. Increase in radiodensity always was found at postoperative intervals greater than one year. An approach to revision total knee arthroplasty that maintains bone and soft tissue about the knee establishes an effective and durable construct. Therapeutic study, level II (prospective study). See Guidelines for Authors for a complete description of levels of evidence.

Midterm Results of Primary Total Knee Arthroplasty Using a Dished Polyethylene Insert with a Recessed or Resected Posterior Cruciate Ligament

Use of a dished polyethylene insert in 114 total knee arthroplasties, all with the posterior cruciate ligament resected or recessed, was retrospectively studied. Patients were evaluated at a mean follow-up of 8.3 years. Mean range of motion increased from 92° to 111°. Mean Knee Society pain and function scores increased from 35.2 and 39.7 to 91.3 and 74.7, respectively. WOMAC scores improved significantly in each category evaluated, including pain, stiffness, and physical function. Kaplan-Meier survivorship was 95% at 10 years (95% confidence interval, 82%-99%). The use of a dished polyethylene insert in primary total knee arthroplasty provides good to excellent midterm results regardless of whether the posterior cruciate ligament is recessed or sacrificed.

Flexion Instability Without Dislocation after Posterior Stabilized Total Knees

Flexion instability after cruciate-retaining total knee arthroplasty has been well documented. We identified an analogous patient group with symptomatic flexion instability without dislocation after primary posterior stabilized total knee arthroplasty. We sought to determine the typical symptoms and exam findings that lead to the diagnosis, to assess the reliability of revision total knee arthroplasty as a treatment, and to assess the technical difficulties encountered during revision total knee arthroplasty. Between 1995 and 2001, 10 patients had revision of a well-fixed posterior stabilized total knee arthroplasty for isolated symptomatic flexion instability. The typical constellation of symptoms and physical findings included a sense of instability without giving way, recurrent knee effusions, multiple areas of soft tissue tenderness about the knee, and substantial anterior tibial translation at 90 degrees of flexion. The revision operation focused on balancing the flexion and extension gaps while taking care to fill the enlarged flexion gap. Revision total knee arthroplasty was reliable in alleviating pain (mean Knee Society Pain scores improved from 68 points preoperatively to 89 points postoperatively), improving stability (nine of 10 patients had < 5 mm anterior tibial translation postoperatively) and improving patient satisfaction (nine of 10 patients were satisfied). We had no particular technical difficulties with the revision total knee arthroplasty procedures and had reliably achieved well-balanced flexion and extension gaps. Therapeutic study, Level IV-1 (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Stiffness After Total Knee Arthroplasty

Stiffness is an uncommon but disabling problem after total knee arthroplasty. The prevalence of stiffness after knee replacement has not been well defined in the literature. In addition, the outcomes of revision surgery for a stiff knee following arthroplasty have not been evaluated in a large series of patients, to our knowledge. The purposes of this study were to define the prevalence of stiffness after primary total knee arthroplasty and to evaluate the efficacy of revision surgery for treatment of the stiffness. We defined a stiff knee as one having a flexion contracture of 15 degrees and/or <75 degrees of flexion. Two separate groups were evaluated. First, the results of 1000 consecutive primary total knee replacements were reviewed to determine the prevalence of stiffness. Second, the results of fifty-six revisions performed because of stiffness, sometimes associated with pain or component loosening, after primary total knee arthroplasty were evaluated. The prevalence of stiffness was 1.3%, at an average of thirty-two months postoperatively. The patients with a stiff knee had had significantly less preoperative extension and flexion than did those without a stiff knee (p < 0.0001). There were no significant differences in age, gender, implant design, diagnosis, or the need for lateral release between the patients with and without stiffness. The second cohort, of knees revised because of stiffness, were followed for an average of forty-three months. The mean Knee Society score improved from 38.5 points preoperatively to 86.7 points at the time of follow-up; the mean Knee Society function score, from 40.0 to 58.4 points; and the mean Knee Society pain score, from 15.0 to 46.9 points. The mean flexion contracture decreased from 11.3 degrees to 3.2 degrees , the mean flexion improved from 65.8 degrees to 85.4 degrees , and the mean arc of motion improved from 54.6 degrees to 82.2 degrees . The arc of motion improved in 93% of the knees, and flexion increased in 80%. Extension improved in 63%, and it remained unchanged in 30%. The prevalence of stiffness in our series of 1000 primary knee arthroplasties was 1.3%. Revision surgery was a satisfactory treatment option for stiffness, as the Knee Society scores improved, the flexion contractures diminished, and 93% of the knees had an increased arc of motion. However, the results suggest that the benefits are modest.

Revision total knee arthroplasty with the Total Condylar III system in inflammatory arthritis

We report a consecutive series of 16 revision total knee arthroplasties using the Total Condylar III system in 14 patients with inflammatory arthritis which were performed between 1994 and 2000. There were 11 women and three men with a mean age of 59 years (36 to 78). The patients were followed up for 74 months (44 to 122). The mean pre-operative Knee Society score of 37 points (0 to 77) improved to 88 (61 to 100) at follow-up (t-test, p < 0.001) indicating very good overall results. The mean range of flexion improved from 62 degrees (0 degrees to 120 degrees) to 98 degrees (0 degrees to 145 degrees) (t-test, p < 0.05) allowing the patients to stand from a sitting position. The mean Knee Society pain score improved from 22 (10 to 45) to 44 (20 to 50) (t-test, p < 0.05). No knee had definite loosening, although five showed asymptomatic radiolucent lines. Complications were seen in three cases, comprising patellar pain, patellar fracture and infection. These results suggest that the Total Condylar III system can be used successfully in revision total knee arthroplasty in inflammatory arthritis.

Total Knee Arthroplasty for Salvage of Failed Internal Fixation or Nonunion of the Distal Femur

Seventeen patients with a mean age of 66 years had total knee arthroplasty (TKA) performed to salvage failed internal fixation or nonunion of the distal femur. Two patients died at less than 2 years, both of whom were unrevised. The remaining 15 were followed for a mean of 5 years. Three arthroplasties failed, 1 by infection and 2 by mechanical failure. The 5-year survivorship free of revision for aseptic failure was 91% (72%-100%). There were 5 intraoperative complications (29%) and 5 postoperative complications (29%). The mean Knee Society pain score improved from 2 (range, 0-10) to 89 (range, 63-97), and the mean functional score improved from 2 (range, 0-25) to 45 (range, 10-90). TKA provided reliable pain relief and functional improvement for the great majority of patients. Functional scores and prosthesis survivorship, however, were inferior to those reported for primary TKA. The surgeries were difficult, and intraoperative and postoperative complications were common.

Functional Results After Revision of Well-Fixed Components for Stiffness After Primary Total Knee Arthroplasty

Between 1990 and 2001, 16 well-fixed, aseptic, primary total knee arthroplasties were revised in 15 patients for a diagnosis of stiffness. Patients were followed for a mean of 42 months (range, 2-6 years). Of 15 patients, 10 (66%) were satisfied with the results of the procedure. The mean Knee Society pain score improved from 28 to 65 points, and the mean functional score improved from 45 to 58 points. The mean arc of motion improved from 40° preoperatively to 73° postoperatively. Recurrent stiffness required additional intervention in 4 knees (3 patients, 25%). The results of revision of a well-fixed, stiff, primary total knee arthroplasty were mixed in our hands and provided only modest improvements in pain, function, and arc of motion.

STIFFNESS AFTER TOTAL KNEE ARTHROPLASTY

Stiffness is an uncommon but disabling problem after total knee arthroplasty. The prevalence of stiffness after knee replacement has not been well defined in the literature. In addition, the outcomes of revision surgery for a stiff knee following arthroplasty have not been evaluated in a large series of patients, to our knowledge. The purposes of this study were to define the prevalence of stiffness after primary total knee arthroplasty and to evaluate the efficacy of revision surgery for treatment of the stiffness. We defined a stiff knee as one having a flexion contracture of >/=15 degrees and/or <75 degrees of flexion. Two separate groups were evaluated. First, the results of 1000 consecutive primary total knee replacements were reviewed to determine the prevalence of stiffness. Second, the results of fifty-six revisions performed because of stiffness, sometimes associated with pain or component loosening, after primary total knee arthroplasty were evaluated. The prevalence of stiffness was 1.3%, at an average of thirty-two months postoperatively. The patients with a stiff knee had had significantly less preoperative extension and flexion than did those without a stiff knee (p < 0.0001). There were no significant differences in age, gender, implant design, diagnosis, or the need for lateral release between the patients with and without stiffness. The second cohort, of knees revised because of stiffness, were followed for an average of forty-three months. The mean Knee Society score improved from 38.5 points preoperatively to 86.7 points at the time of follow-up; the mean Knee Society function score, from 40.0 to 58.4 points; and the mean Knee Society pain score, from 15.0 to 46.9 points. The mean flexion contracture decreased from 11.3 degrees to 3.2 degrees, the mean flexion improved from 65.8 degrees to 85.4 degrees, and the mean arc of motion improved from 54.6 degrees to 82.2 degrees. The arc of motion improved in 93% of the knees, and flexion increased in 80%. Extension improved in 63%, and it remained unchanged in 30%. The prevalence of stiffness in our series of 1000 primary knee arthroplasties was 1.3%. Revision surgery was a satisfactory treatment option for stiffness, as the Knee Society scores improved, the flexion contractures diminished, and 93% of the knees had an increased arc of motion. However, the results suggest that the benefits are modest.

Total knee arthroplasty following proximal tibial osteotomy: risk factors for failure.

The results of proximal tibial osteotomy are known to deteriorate over time, with the majority of patients eventually requiring total knee arthroplasty. The outcome of total knee arthroplasty in patients who have had a proximal tibial osteotomy, compared with that of routine primary total knee arthroplasty, remains controversial. The purpose of the present study was to evaluate the long-term clinical and radiographic outcome of total knee arthroplasty in patients who had undergone a previous proximal tibial osteotomy and to identify the risk factors that may result in an inferior outcome. Between 1980 and 1990, 166 cemented condylar total knee prostheses were implanted in 118 patients who had had a previous proximal tibial osteotomy for the treatment of osteoarthritis. The study group included seventy-seven men and forty-one women who had a mean age of 69.1 years at the time of knee arthroplasty. The average interval between the osteotomy and the total knee arthroplasty was 8.6 years. The average duration of clinical follow-up was 15.1 years, and the average duration of radiographic follow-up was 9.2 years. The mean Knee Society pain score improved from 34.5 to 82.9 points, and the mean function score improved from 44.6 to 88.1 points. There was also a substantial improvement in the mean arc of motion. Thirteen knees (8%) were revised at a mean of 5.9 years. At the time of the final follow-up, progressive complete radiolucent lines indicating a loose prosthesis were present around seventeen tibial components and seven femoral components. There was a very high rate of radiographic evidence of loosening. Male gender, increased weight, young age at the time of total knee arthroplasty, coronal laxity, and preoperative limb malalignment were identified as risk factors for early failure. Despite these findings, total knee arthroplasty can provide reliable and durable pain relief and improvement in function for patients who have had a previous proximal tibial osteotomy. Prognostic study. Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.