Patella resurfacing versus nonresurfacing in total knee arthroplasty: results of a randomized controlled clinical trial at a minimum of 10 years' followup

Patellar resurfacing in total knee arthroplasty remains controversial. This study evaluates the results of resurfacing and nonresurfacing the patella in a randomized controlled, clinical trial at a minimum of 10 years followup. One hundred knees (90 patients) with osteoarthritis were enrolled in a prospective randomized clinical trial using a posterior-cruciate-retaining total knee arthroplasty. Patients were randomized to receive resurfacing or retention of the patella. Evaluations were done preoperatively and yearly, up to a minimum of 10 years (range, 10.1-11.5 years) postoperatively. Disease-specific (Knee Society clinical rating score) and functional (stair climbing, flexion/extension torques, patellar examination) outcomes were measured. Patient satisfaction, anterior knee pain, and patellofemoral questionnaires were completed. Intraoperative grading of the articular cartilage was done. No patients were lost to followup; 45 patients remained alive. Nine revisions (in nine of 90 knees; 10%) were done in seven patients in the nonresurfaced group (15% of knees) and in two patients in the resurfaced group (5% of knees). No significant difference was found between the groups regarding revision rates, Knee Society clinical rating scores, and functional, patient satisfaction, anterior knee pain, patellofemoral, and radiographic outcomes. Intraoperative cartilage quality was not a predictor of outcome. This study currently is the longest followup of a randomized controlled, clinical trial that examines patellar resurfacing in total knee arthroplasty. The results showed no significant difference between the groups for all outcome measures at a minimum of 10 years of followup.     

Patellar resurfacing in total knee arthroplasty. A prospective, randomized, double-blind study with five to seven years of follow-up

BACKGROUND: Whether to resurface the patella during a primary total knee arthroplasty performed for the treatment of degenerative osteoarthritis remains a controversial issue. Parameters that have been suggested as being useful in guiding this decision include patient height and weight, the presence of anterior knee pain preoperatively, and the grade of chondromalacia encountered intraoperatively. The purpose of this study was to determine whether these parameters were predictive of the clinical result following total knee arthroplasty with or without patellar resurfacing. METHODS: Eighty-six patients (118 knees) undergoing primary total knee arthroplasty for the treatment of osteoarthritis were enrolled in a prospective, randomized, double-blind study. All patients received the same posterior-cruciate-sparing total knee prosthetic components. Patients were randomized to treatment with or without resurfacing of the patella. Evaluations consisted of the determination of a Knee Society clinical score, the completion of a patient satisfaction questionnaire, specific questions relating to patellofemoral symptoms, and radiographs. Sixty-seven patients (ninety-three knees) were followed for a minimum of five years (range, sixty to eighty-four months; average, 70.5 months). RESULTS: With the numbers available, there was no significant difference between the groups treated with and without resurfacing with regard to the overall Knee Society score or the pain and function subscores. Obesity, the degree of patellar chondromalacia, and the presence of preoperative anterior knee pain did not predict postoperative clinical scores or the presence of postoperative anterior knee pain. CONCLUSIONS: The occurrence of anterior knee pain could not be predicted with any clinical or radiographic parameter studied. On the basis of these results, it seems likely that postoperative anterior knee pain is related either to the component design or to the details of the surgical technique, such as component rotation, rather than to whether or not the patella is resurfaced.     

Patellar resurfacing in total knee arthroplasty. A prospective,randomized study

BACKGROUND: Anterior knee pain following total knee arthroplasty is a common complaint and typically is attributed to the patellofemoral joint. The purpose of the present study was to compare the outcome of resurfacing and nonresurfacing of the patella, particularly with regard to anterior knee pain, and to clarify the indications for patellar resurfacing at the time of total knee arthroplasty. METHODS: We performed a prospective, randomized study of 514 consecutive primary press-fit condylar total knee replacements. The patients were randomized to either resurfacing or retention of the patella. They were also randomized to either a cruciate-substituting or a cruciate-retaining prosthesis as part of a separate trial. The mean duration of follow-up was 5.3 years (range, two to 8.5 years), and the patients were assessed with use of the Knee Society rating, a clinical anterior knee pain score, and the British Orthopaedic Association patient-satisfaction score. The assessment was performed without the examiner knowing whether the patella had been resurfaced. At the time of follow-up, there were 474 knees. Thirty-five patients who had a bilateral knee replacement underwent resurfacing on one side only. RESULTS: The overall prevalence of anterior knee pain was 25.1% (fifty-eight of 231 knees) in the nonresurfacing group, compared with 5.3% (thirteen of 243 knees) in the resurfacing group (p < 0.0001). There was one case of component loosening. Ten of eleven patients who underwent secondary resurfacing had complete relief of anterior knee pain. The overall postoperative knee scores were lower in the nonresurfacing group, and the difference was significant among patients with osteoarthritis (p < 0.01). There was no significant difference between the resurfacing and nonresurfacing groups with regard to the postoperative function score. Patients who had a bilateral knee replacement were more likely to prefer the resurfaced side. CONCLUSIONS: As the present study showed a significantly higher rate of anterior knee pain following arthroplasty without patellar resurfacing, we recommend patellar resurfacing at the time of total knee replacement when technically possible.     

全膝关节置换术中髌骨面修整与髌骨置换的比较研究

目的比较全膝关节置换术髌骨面修整和髌骨置换的临床结果。方法2002年1月至12月对60例（60膝）行初次全膝关节置换术的骨性关节炎患者进行前瞻性、随机化研究。所有患者接受相同的后交叉韧带替代型全膝关节假体（PFC）,患者随机行髌骨面修整（髌骨面修整组）或髌骨置换（髌骨置换组）。58例患者平均随访54个月（40～60个月）,对其进行临床评价,包括膝关节协会评分（KSS）、膝关节活动度（ROM）、患者满意度和X线检查。结果两组患者KSS总评分（P=0．12）、KSS疼痛评分（P=0．90）、患者满意度（P=0．22）无明显差异;两组术后膝前痛的发生率均为10％亦无明显差异。两组ROM（P=0．028）和KSS功能评分（P=0．0098）差异有统计学意义。结论全膝关节置换术不论是髌骨面修整还是髌骨置换均能明显减轻疼痛和改善功能。术后膝前痛可能与假体设计和手术技术有关,并非与是否置换髌骨有关。     

全膝关节置换术中髌骨置换与髌骨成形对膝关节功能的影响

 目的 探讨髌骨置换与髌骨成形对全膝关节置换术后膝关节功能的影响。方法 对2010年8月至11月拟行全膝关节置换术的48例(69膝)膝关节骨关节炎患者进行随机分组,髌骨置换组24例(35膝)、髌骨成形组24例(34膝)。两组患者年龄、体重、身高、体重指数、美国膝关节协会(Knee Society Score,KSS)膝评分及功能评分、髌骨评分的差异均无统计学意义。比较两组术后6周、3个月、6个月、12个月、24个月的KSS膝评分及功能评分、髌骨评分、术后膝前痛发生率及影像学表现。结果 髌骨置换组20例(30膝)与髌骨成形组20例(29膝)获得随访。术后各时点两组KSS膝评分的差异无统计学意义;6个月以后髌骨置换组KSS功能评分高于髌骨成形组,12个月以后髌骨置换组髌骨评分高于髌骨成形组,差异有统计学意义。术后各时点髌骨置换组膝前痛发生率与髌骨成形组的差异有统计学意义。术后24个月髌骨置换组与髌骨成形组术后胫股角(174.25°±0.97°与173.63°±0.48°)、髌韧带比值(1.01±0.09与1.09±0.07)、髌骨倾斜角(4.58°±0.18°与4.41°±0.19°)、髌骨适合角(2.69°±4.15°与2.56°±3.72°)、髌骨移位距离[(1.53±1.34) mm与(1.68±1.23) mm]的差异均无统计学意义。结论 全膝关节置换术中行髌骨置换可以改善膝关节和髌骨功能,降低术后膝前痛的发生率。     

Resurfacing versus not resurfacing the patella in total knee arthroplasty: 8- to 10-year results

Patellar resurfacing in total knee arthroplasty is a topic debated in the literature. Concerns include fracture, dislocation, loosening, and extensor mechanism injury. Residual anterior knee pain has been reported when the patella is not resurfaced. One hundred patients with osteoarthritic knees were prospectively randomized to either have their patella resurfaced or left not resurfaced. All patients were treated with a single prosthesis that featured an anatomically designed patellofemoral articulation (Anatomic Medullary Knee, DePuy, Warsaw, IN) Two patients in the unresurfaced group and one in the resurfaced group required repeat surgery for patellofemoral complications. At 8- to 10-year follow-up evaluations, Knee Society Clinical Ratings scores were not different between the 2 groups. Rates of anterior knee pain with walking and stair climbing were significantly less in the resurfaced group. Eighty percent of patients with a resurfaced patella were extremely satisfied with their total knee arthroplasty versus 48% without patellar resurfacing. When satisfied and extremely satisfied patients were grouped together, there was no difference between the 2 groups.     

Advantages of patellar resurfacing in total knee arthroplasty

Complications of patellar resurfacing in total knee arthroplasty have rekindled the interest of many surgeons in patellar retention. In a prospective study 20 randomly selected patients of 40 underwent patellar resurfacing in combination with their total knee arthroplasty. The other 20 patients were left with an unresurfaced patella. Within 24 months of follow-up, the advantages of patellar resurfacing could be seen according to the Knee Society Score. Especially in advanced osteoarthritis of the knee joint, the patients achieved better scores in climbing stairs and in function. The superior functional results are arguments for patellar resurfacing, at least in knees with advanced osteoarthritis.     

Isolated Resurfacing of the Previously Unresurfaced Patella Total Knee Arthroplasty

Postoperative anterior knee pain can be challenging after primary total knee arthroplasty. Isolated patellar resurfacing may provide symptomatic improvement in those patients with an unresurfaced patella. Seventeen isolated patellar resurfacing procedures were performed. Patient outcomes were evaluated using the Knee Society clinical and roentgenographic evaluation systems. Continued symptomatology and overall patient satisfaction were also analyzed. No revisions have been necessary at 47 months of follow-up. Overall, Knee Society knee scores and knee function scores significantly improved. Eight patients (53%) are asymptomatic and were satisfied with the procedure, whereas 7 patients (47%) continue to have anterior knee pain and are unsatisfied. Isolated patellar resurfacing for anterior knee pain in total knee arthroplasty with an unresurfaced patella has a low morbidity and revision rate but may not provide patients with predictable symptomatic improvement.     

Arthroscopic treatment of patellar clunk.

Excellent results have been reported with posterior stabilized total knee arthroplasty. A common complication relating to patellofemoral articulation is patellar clunk syndrome. Patellar clunk syndrome occurs when a fibrous nodule develops just proximal to the patellar button. At approximately 30 degrees to 45 degrees from full extension, the nodule catches the anterior flange of the femoral prosthesis, resulting in the clunk and a painful range of motion. The present study examines the use of arthroscopic debridement for this disorder. Thirty consecutive patients (32 knees) with the diagnosis of patellar clunk syndrome were evaluated at 1 year after arthroscopic debridement. All patients were evaluated clinically and radiographically according to the Knee Society score. In addition, patients were questioned specifically regarding anterior knee pain and patellofemoral symptoms. Radiographs were evaluated further regarding patella and component position. Patients were diagnosed with patellar clunk at an average of 12 months after their latest knee arthroplasty, with a range of 3 to 47 months. All patients complained of anterior knee pain and the clunk. All patients had a hypertrophic nodule at the junction of the proximal pole of the patella and quadriceps tendon and underwent arthroscopic debridement through a superolateral portal. All patients were free of patellar clunk postoperatively; one patient reported persistent anterior knee pain. Knee Society scores increased from an average of 64 points preoperative to 93 points postoperative. Radiographs showed patella alta in eight knees, patella baja in two. Four femoral components were in 5 degrees flexion. The present study represents the largest collection of data regarding patellar clunk syndrome. The data appear to support arthroscopic debridement as a successful treatment of patellar clunk syndrome.     

Patellar resurfacing in total knee arthroplasty: a prospective, randomized trial

BACKGROUND: The management of the patella in total knee arthroplasty is still problematic. We aimed to identify differences in the clinical outcome of total knee arthroplasty according to whether or not patellar resurfacing had been performed in a prospective, randomized study of 220 osteoarthritic knees. METHODS: Two hundred and twenty total knee arthroplasties in 201 patients were randomly assigned to be performed with either resurfacing or retention of the patella, and the results were followed for a mean of forty-eight months (range, thirty-six to seventy-nine months) in a double-blind (both patient and clinical evaluator blinded), prospective study. Evaluation was performed annually by an independent observer and consisted of assessment with the Knee Society clinical rating system, specific evaluation of anterior knee pain, a stair-climbing test, and radiographic examination. RESULTS: Fifteen (12%) of the 128 knees without patellar resurfacing and nine (10%) of the ninety-two knees with patellar resurfacing underwent a revision or another type of reoperation related to the patellofemoral articulation. This difference was not significant (chi square with one degree of freedom = 0.206, p = 0.650). At the time of the latest follow-up, there was a significantly higher incidence of anterior pain (chi square with one degree of freedom = 5.757, p = 0.016) in the knees that had not had patellar resurfacing. CONCLUSIONS: Patients who underwent patellar resurfacing had superior clinical results in terms of anterior knee pain and stair descent. However, anterior knee pain still occurred in patients with patellar resurfacing, and nine (10%) of the ninety-two patients in that group underwent a revision or another type of reoperation involving the patellofemoral joint. Weight but not body mass index was associated with the development of anterior knee pain in the patients without patellar resurfacing, a finding that suggests that patellofemoral dysfunction may be a function of joint loading rather than obesity.     

Total knee arthroplasty in patients with isolated patellofemoral arthritis.

The current study evaluated the results of total knee arthroplasty for the treatment of isolated patellofemoral degenerative arthritis. Between 1980 and 1997, 31 total knee arthroplasties were done in 24 patients with advanced, isolated patellofemoral arthritis. The average followup was 5.2 years (range, 2-12 years). There was a significant improvement in the mean preoperative Knee Society pain and function scores. Twenty-one knees required a lateral retinacular release and three knees required additional formal proximal realignment at the time of the total knee arthroplasty. There were three reoperations in this series including, manipulation for poor motion in one patient; revision of a loose patellar component in one patient; and extensor mechanism realignment in the third patient. At midterm followup, total knee arthroplasty proved to be reliable and durable in alleviating pain and improving function in this group of patients with isolated, advanced patellofemoral arthritis. Surgeons should be made aware, however, that resurfacing of the patella and balancing the extensor mechanism for patients with isolated patellofemoral arthritis can be demanding technically as evidenced by the high rate of asymmetrically resurfaced patellas, the high rate of lateral retinacular release, and formal realignment procedures.     

Patellar Resurfacing in Primary Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials

BackgroundThe management of the patella during total knee arthroplasty (TKA) remains controversial. The aim of this study is to evaluate the evidence regarding the use of patellar resurfacing in TKA.MethodsA meta-analysis of randomized controlled trials (RCTs) was performed to compare outcomes between knees receiving patellar resurfacing vs those not receiving resurfacing during primary TKA. Outcomes of interest were the Knee Society Scores, reoperation rates, anterior knee pain, patient satisfaction, Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score subscores, and range of motion.ResultsTwenty RCTs met all eligibility criteria and were included in the analysis. There were statistically significant differences favoring the resurfaced group in the knee component and functional component of Knee Society Scores that were not clinically significant. There was an increased risk of reoperation among knees that did not receive resurfacing with number needed to treat to prevent one case of reoperation of 25 knees (for reoperation for any reason) and 33 knees (for reoperation for anterior knee pain). There were no statistically significant differences in any other outcomes.ConclusionThe only clear relationship is that knees that do not receive patellar resurfacing are more likely to receive reoperation, most often for secondary resurfacing. However, the disease burden of differing complication profiles associated with resurfacing and nonresurfacing groups remains unclear. Continuing to collect data from large, well-designed RCTs would be beneficial in guiding management of the patella during TKA.     

Patella resurfacing in posterior stabilised total knee arthroplasty: a follow-up study in 56 patients

Patellar resurfacing in total knee arthroplasty (TKA) remains controversial. This study evaluates the results of resurfacing and non-resurfacing of the patella. Fifty-six patients with osteoarthritis (OA) of the knee were enrolled in a prospective randomised clinical trial using a posterior-stabilised TKA. Evaluations were done preoperatively and after 1, 3, 6, 12 and 24 months. Disease specific (Knee Society Score or KSS) and functional (patella-related activities) outcomes were measured. Patient satisfaction and anterior knee pain questionnaires were completed. No patients were lost to follow-up. No significant differences were found between groups with regard to the clinical part of the Knee Society score (KSS) not even in obese patients, the ability of performing daily activities involving the patellofemoral joint, and patient satisfaction. Significant differences were found regarding the functional section of the KSS, passive flexion, anterior knee pain and patellar tilt and subluxation. In conclusion, the authors believe that, for the implant studied, patellar resurfacing can be indicated.     

膝关节骨关节炎患者初次全膝关节置换术中选择髌骨置换的Meta分析

目的探讨膝关节骨关节炎(OA)进行初次全膝关节置换术(TKA)中选择髌骨置换与否的疗效,评价两种不同治疗选择的差异。方法检索Medline、Embase、Cochranelibrary、CBM,收集膝关节OA行初次TKA术中髌骨置换与否的临床对照试验,提取数据分析,采用RevMan5.0.18进行Meta分析。结果纳入8个前瞻性随机对照试验,共822例手术,其中髌骨置换组373例,髌骨非置换组444例。髌骨置换与非置换组比较,前膝痛与KSS评分均无明显的统计学意义(P0.5),置换组的因髌股关节问题而再次手术率低于非置换组[RR=0.53,95%CI(0.29,0.96),P=0.04],但置换组再次手术的原因除了常见的前膝痛,还包括髌骨假体相关的并发症。结论膝关节OA的患者行初次TKA术中选择髌骨置换与否的前膝痛与KSS评分无明显的统计学意义,置换组的因髌股关节问题再次手术率低于非置换组,但置换组再次手术的复杂性大于非置换组。     

髌骨置换与否对全膝关节置换术后疗效的影响

目的 探讨膝骨关节炎患者行全膝关节表面置换时髌骨置换与否对术后疗效及并发症发生的影响.方法 对2007年1月至2011年12月之间行人工全膝关节置换术的170例(237膝)骨关节炎患者,按髌骨置换(126膝)和未置换(111膝)分为2组.对术前和末次随访时两组的HSS评分、膝前痛评分、膝关节活动度、最大屈曲度数、屈曲畸形及手术时情况和患者满意度等进行对比分析.结果使用SPSS 17.0统计软件包进行统计学分析.结果 在170例(237膝)OA患者中161例(21 3膝)获得随访,平均随访时间(40.94±8.02)个月,置换组HSS评分由术前的(40.19±8.14)分增加到末次随访时的(87.45±6.00)分(P＜0.05),膝前痛评分由(4.13±1.08)分升高到(19.47±4.04)分(P＜0.05);未置换组HSS评分由(40.00±6.74)分上升到(88.93±4.92)分(P＜0.05),膝前痛评分由(3.58±2.26)分变化到(13.61±3.89)分(P＜0.05);患者满意度置换组为80.91％,未置换组为61.17％(P＜0.05).在HSS评分、膝关节活动度、最大屈曲度数、屈曲畸形等方面两组差异无统计学意义.而在膝前痛评分、患者满意度、手术时间、术中失血量等方面差异有统计学意义.结论 当膝关节骨关节炎患者进行全膝关节置换术时,若术前存在膝关节疼痛严重、患者期望较高、不适合长时间手术,应行髌骨置换.     

Patella resurfacing in patients without substantial retropatellar knee pain symptoms?

OBJECTIVE: The aim is of this prospective randomised study was to investigate the necessity of resurfacing the patella in combination with total knee arthroplasty in patients without or mild anterior knee pain before undergoing total knee replacement. METHODS: Between May 1999 and May 2000 fifty patients were enrolled in a prospective, randomised study. All patients received the same posterior-cruciate-sparing total knee replacement and were randomised to treatment with and without resurfacing of the patella. Inclusion criteria were primary osteoarthritis of the knee, preoperatively no pain when the patella was shifted during clinical examination, a maximal grade III radiological degeneration of the patella according to Sperner et al. and at most a mild anterior knee pain in preoperative interview. Evaluations consisted of the determination of the Knee Society clinical score, the completion of a patient satisfaction questionnaire, and radiographic assessment basing on the Knee Society roentgenographic evaluation and scoring system. All patients were examined preoperatively and 3, 6, and 12 months postoperatively. RESULTS: In all postoperative examinations patients with patella resurfacing demonstrated a higher overall Knee Society score. At month 6 the difference was statistically significant. The patient satisfaction questionnaire demonstrated no significant difference between both groups. However, regarding to relief of anterior knee pain and improvement of pain in general patients with nonresurfacing were less satisfied at all follow-ups. Furthermore, after 12 months all answers to the patient satisfaction questionnaire of the resurfaced group were better. Patella-associated revisions were performed in two patients without resurfacing. Radiographic analysis demonstrated no loosening, fracture, subluxation or dislocation. CONCLUSION: The presented study demonstrated after one year follow-up a better functional result, a higher degree of contentment and fewer complications after total knee replacement with patella resurfacing in patients without or mild preoperative anterior knee pain.     

Total knee arthroplasty in an adult with congenital dislocation of the patella

This article reports the use of total knee arthroplasty with release of the lateral retinaculum, proximal extensor mechanism realignment, and patellar resurfacing as a valid treatment option for adult patients with congenital dislocation of the patella who have absence of the femoral sulcus and associated osteoarthritis. The patient presented in this case report had improvement of his Knee Society knee score and function score from preoperative levels of 8 and 45 to 77 and 80 postoperatively.     

Total knee arthroplasty without patellar resurfacing

One hundred and eleven total knee replacements without patellar resurfacing were followed-up for a minimum of 48.8 months (range 48.8-108.2 months; average 78.2 months). Evaluation was performed using the Knee Society Clinical Rating System (KS-CRS). Preoperatively, the mean knee score was 34.3 points and the mean function score was 42.2 points. Postoperatively, this knee score improved to a mean of 91.1 points and the function score improved to mean of 89.6 points at the most recent follow-up. There were no significant differences among the knees with mild, moderate, or severe degenerative change to the patella with regard to the preoperative (p=0.83) and postoperative (p=0.39) knee pain score. It seems likely that the postoperative knee pain is not related to the severity of degenerative change to the patella in total knee arthroplasties performed without patellar resurfacing, and none of those patients required patellar resurfacing to achieve knee pain relief.     

Patellar resurfacing reduces pain after TKA for juvenile rheumatoid arthritis

Influence of patellar resurfacing after knee replacement and the frequency of patella infera and its relation to the postoperative appearance of the knee pain were assessed in patients with juvenile rheumatoid arthritis. Seventy-seven total knee arthroplasties using the AGC prosthesis with nonconstrained components were done on 52 patients with a mean followup of 7.3 years (range, 3-13 years). Anterior knee pain was present in 14 of 30 patients (47%) with an unreplaced patella and in two of 18 patients (11%) with patella resurfacing. The patella was replaced in 18 patients (35%) and in 23 of 77 knees (30%). Neither revision surgery of implanted patellar components nor any later resurfacing of an unreplaced patella were done during the followup. Preoperatively using the Insall-Salvati ratio, the majority of knees (54 of 77) had a low-riding patella. Patella infera occurred commonly in patients with juvenile rheumatoid arthritis. No connection between patella infera and anterior knee pain was found.     

Ten- to 12-year followup of the Insall-Burstein I total knee prosthesis

The Insall-Burstein Posterior Stabilized knee prosthesis (Insall-Burstein I), developed at The Hospital for Special Surgery in 1978, has a metal-backed nonmodular tibial component. The polyethylene articular surface was directly molded. The purpose of the current study was to evaluate long-term wear with this design. The first 100 total knee arthroplasties (86 patients) performed by the senior author were followed prospectively. The average age of the patients at the time of surgery was 69.7 years (range, 45-89 years). The primary diagnoses were osteoarthritis in 77 knees (66 patients), inflammatory arthritis in 17 knees (14 patients), and posttraumatic arthritis in the remaining six knees (six patients). Thirty-eight knees (35 patients) had varus angulation, 14 knees (13 patients) had valgus angulation, and 48 knees (40 patients) had a 0 degrees to 10 degrees tibiofemoral angle preoperatively. All patients were evaluated at 10 to 12 years followup. Knee Society scores and radiographs were obtained. Thirty-six knees were in 30 patients who had died and two knees were in two patients who were infirm. Telephone evaluation only was available for eight knees (seven patients), leaving 54 knees (47 patients) for direct clinical and radiographic evaluation. No patients were lost to followup. The average Knee Society clinical score at latest followup was 91.6 points. The average function score was 69 points. One knee arthroplasty failed because of tibial loosening, one failed because of patella wear and fracture, two failed because of sepsis, and two failed because of nonspecific pain. There were seven patella fractures (7%) in the 100 knees. One of the fractures resulted in a total knee revision (noted above), two resulted in patellar component revision, and another resulted in patellar component removal. The remaining three patella fractures were discovered incidentally and were asymptomatic. There were no patellar dislocations. At long-term radiographic analysis, valgus alignment averaged 6 degrees (range, 0 degrees-11 degrees). Polyethylene wear averaged 0.40 mm. There was no catastrophic wear of tibial polyethylene. Thirty-two knees in 32 patients (65%) had radiolucencies in at least one zone; no lucency filled a zone, and none was wider than 2 mm. The absence of clinically significant tibial polyethylene wear at long-term followup is of particular interest. The performance of the molded, nonmodular polyethylene articulation is encouraging and needs to be analyzed critically against the more widely used machined, modular components used today.