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.     

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.     

Resurfacing versus nonresurfacing the patella in total knee arthroplasty: a critical appraisal of the available evidence

A systematic literature search for evidences comparing treatment effect and harm of resurfacing versus nonresurfacing the patella in total knee arthroplasty was conducted and yielded five meta-analysis (MA), one systematic review (SR) and six randomized controlled trials not included in previous MAs/SR. The evidence suggests that patellar resurfacing would reduce the risk of anterior knee pain, as well as the risk of patella-related reoperation. Furthermore, patients not undergoing patella resurfacing would experience more knee pain during stair climbing and be less satisfied with surgery. No significant difference in range of motion can be expected with or without patellar resurfacing. Importantly, methodological limitations were observed in all retrieved studies and evidences about potential adverse events related to patellar resurfacing are presently undetermined.     

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。     

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.     

Outcomes of patellar resurfacing versus nonresurfacing in total knee arthroplasty: a 9-year experience based on a case series of scorpio PS knees

Patellar resurfacing during total knee arthroplasty (TKA) is an actively debated issue. This prospective study addresses fundamental questions regarding whether to resurface the patella. To do this, we compared clinical results of Scorpio PS knees with and without patellar resurfacing to determine whether there was any statistically significant difference in survivorship, function, pain, and radiographic analyses. Our study failed to demonstrate any statistical difference between the 2 groups (resurfaced versus nonresurfaced) according to knee pain, walking abilities, stair climbing, range of motion, and radiologic findings, as well as cross-correlations between patellar pain and age, gender, obesity, or etiology. Our radiologic findings did not reveal any failures of bony structures facing the metallic flange. Some knee designs can thus be seen as "patella friendly." Given the significant cost of patella resurfacing and the resulting well-known complications, we continue to avoid systematic resurfacing of the patella during Scorpio TKA.     

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.     

Anterior knee pain in rheumatoid patients after total knee replacement. Possible selection criteria for patellar resurfacing.

Postoperative anterior knee pain was evaluated in a consecutive series of 138 knees in 108 patients with rheumatoid arthritis treated by total knee replacement with Mark I Insall-Burstein prostheses. No knee had primary patellar resurfacing, and in the 119 knees followed up for a mean of 63.9 months, none had secondary resurfacing. Anterior knee pain was absent in 87 knees (73%), mild in 16 (13.5%) and moderate or severe in 16 (13.5%). The height of the patella above the prosthetic joint line was the only variable which was directly related to the incidence of anterior knee pain. The sensitivity and specificity of patellar height measurements for identifying patients with or without pain were derived. From these data, a selective policy of resurfacing the patella in those at risk was adopted. Choosing a patellar height of 15 mm or less, patellar resurfacing could be avoided in 80% of patients likely to have no pain, and the patella could be resurfaced in 65% of those likely to have anterior knee pain.     

Patellar resurfacing complications in total knee arthroplasty

Purpose

The ideal management of the patella during total knee arthroplasty (TKA) is still controversial. Patellar retention is generally associated with an increased rate of anterior knee pain; however, patient satisfaction is similar in cases of replacement or retention. When the patella is replaced, potential severe complications can occur. Aim of this study was to retrospectively review results of a continuous series of patients having been treated with TKA and patella resurfacing.

Methods

The charts of 1,600 consecutive total knee prostheses were analysed to evaluate the rate of patellar resurfacing. All implants were posterior stabilized; 310 patients having received a patellar replacement were reviewed at follow-up (FU) examination. Complete physical examination as well as administration of the Hospital for Special Surgery (HSS) score was performed. X-rays analysis included weightbearing anteroposterior (AP) and lateral views of the injured knee and bilateral skyline views at 30° flexion.

Results

Two hundred and eighty patients were available for clinical and imaging investigation at an average FU of 96 (58–144) months. Mean age at the time of surgery was 70 (62–80) years. Mean HSS score was 85.9 ± 7.6. The overall rate of patellofemoral complications was 7 % (19 cases); 13 patients claimed anterior knee pain, five had symptomatic patellar maltracking and one had patellar component loosening.

Conclusion

Our data are in accordance with those available in the literature. Recent meta-analyses demonstrated lower risk of re-operation after patellar resurfacing. However, when complications of the resurfaced patella occur, they can be potentially catastrophic events.     

Kinematic total knee arthroplasty: a 10- to 14-year prospective follow-up review.

To understand better the type and incidence of long-term complications in total knee replacement, 306 primary Kinematic total knee arthroplasties performed between June 1978 and December 1982 were prospectively reviewed in detail. The Kinematic knee is a nonconstrained, posterior cruciate-retaining prosthesis that has right and left femoral components to afford anatomic tracking of the patella. The overall revision rate was 6.5%. The most common cause for revision surgery was patellar complications. Ten revisions (3.06%) were for patellar component loosening. Two knees were revised for patella subluxation (0.65%); 1 was in a resurfaced rheumatoid patella, and 1 in an unsurfaced osteoarthritic patella. Stair climbing was better with an unsurfaced patella. Anterior knee pain was 21.8% in the unsurfaced patella and 11.2% in the replaced patella. These data suggest patella replacement is not appropriate with this design.     

Walking, chair rising, and stair climbing after total knee arthroplasty: patellar resurfacing versus nonresurfacing

During the past decade, the technology and design of knee joint prostheses has progressed considerably. However, there is still much controversy on whether resurfacing the patella during routine total knee arthroplasty (TKA) is necessary. This study compares the biomechanics of the lower limb in patients after TKA with and without patellar resurfacing during level walking, stair climbing, and chair rising. Eighteen patients who underwent TKA by two different surgeons using the same prosthesis were studied after full rehabilitation while walking, stair climbing, and chair rising. Patients were divided between those who were resurfaced and those who were not resurfaced. An aged-matched control population was recruited for comparison. The Hospital for Special Surgery Knee Rating Scale was used to gather clinical information. Kinematic and kinetic parameters were collected using a 5-camera Motion Analysis System and an AMTI OR6-5 force platform. For level walking, patients were asked to walk at a self-selected speed down an 8-m walkway. For stair climbing, patients were asked to climb a 4-step staircase without handrail support and for chair rising, patients were asked to rise from a chair that was positioned at the height of their knee joint line. Five trials for each side were recorded for averaging and statistical analysis. Temporal-spatial parameters and kinematic and kinetic variables at the knee joint were tested for significance using the repeated measures analysis of variance (ANOVA). There were no significant differences in the biomechanics of walking, stair climbing, or chair rising between patients after TKA with and without a resurfaced patella.     

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。     

The need for patellar resurfacing in total knee arthroplasty: a literature review

The controversy over whether or not to routinely resurface the patella during a total knee arthroplasty has persisted despite three decades of successful joint replacement procedures. Advocates for routine patellar resurfacing admit the occasional need for secondary patellar resurfacing and declare increased incidence of anterior knee pain in patients with non‐resurfaced patellae as a cause for worry. Surgeons that leave the patella unresurfaced cite avoidance of complications that include patellar fracture, avascular necrosis, patellar tendon injury and instability. This review discusses the available literature on patellar resurfacing through an evidence‐based analysis of randomized and pseudo‐randomized controlled trials and published meta‐analyses to date. The published literature seems to favour resurfacing the patellar routinely. Selective patellar resurfacing would be the ideal solution if sound pre‐operative criteria could be established. So far, a method for accurately predicting which patients can avoid patellar resurfacing has not been found. Future research looking at patellar resurfacing should concentrate on developing criteria for selecting those patients that would benefit from patellar resurfacing and those that would do as well without resurfacing, and thus, limiting potential surgical complications.     

The role of patellar resurfacing in TKA. Point

While controversy persists, scientific evidence favoring patellar resurfacing in primary TKA is abundant. The literature demonstrates a substantially higher incidence of anterior knee pain and reoperation rates if the patella is not resurfaced primarily. Prospective, randomized studies have reported reoperation rates to convert unresurfaced patellas to resurfaced patellas exceed those for complications after patellar resurfacing. When resurfacing the patella, strict surgical principles are paramount to avoid complications. These include duplicating the original patella thickness, maintaining the patellar blood supply, achieving central patellar tracking, and properly positioning the femoral, tibial, and patellar components. Optimum prosthetic design features for patella resurfacing include an anatomic, asymmetric trochlear groove that is broad, extended, (distally and posteriorly) and deeper compared with first-generation designs.     

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.     

Osteonecrosis of bipartite patella following total knee arthroplasty without lateral release

We present a case of osteonecrosis of bipartite patella occurring after total knee arthroplasty using medial parapatellar approach without lateral retinacular release in osteoarthritic knee of a 66 year-old-male. The surgery was performed using traditional technique with medial parapatellar approach and patella was resurfaced. Patella was everted during surgery. There was no event during follow-up period after surgery. Range of motion of the knee was 135° without flexion contracture. Eight months after the surgery, patella was fragmented and resorbed on the radiographs which was consistent with osteonecrosis. The patient showed extension limitation of 30° with no pain. Patellar osteonecrosis has been rarely reported after total knee arthroplasty with lateral retinacular release. However, there was no report of patellar osteonecrosis after total knee arthroplasty without lateral retinacular release. Caution should be taken about patellar osteonecrosis in case of bipartite patella even though lateral retinaculum is preserved during total knee arthroplasty.     

Systematic review of patellar resurfacing in total knee arthroplasty

Controversies existing over resurfacing the patella in total knee arthroplasty remain in the literature. The purpose of this review was to evaluate the effectiveness of resurfacing versus nonresurfacing the patella in total knee arthroplasty. We searched the Cochrane Library, MEDLINE and EMBASE for published randomised clinical trials relevant to patellar resurfacing. The relative risk of reoperation was significantly lower for the patellar resurfacing group than for the nonresurfacing group (relative risk 0.57, 95% confidence interval 0.38–0.84, P = 0.004). The overall incidence of postoperative anterior knee pain of the 1,421 knees included was 12.9% in the patellar resurfacing group and 24.1% in the nonresurfacing group. The existing evidence indicates that patellar resurfacing can reduce the risk of reoperation with no improvement in postoperative knee function or patient satisfaction over total knee arthroplasty without patellar resurfacing. Whether it can decrease the incidence of anterior knee pain remains uncertain.     

The patellofemoral joint in total knee arthroplasty: is the design of the trochlea the critical factor?

The outcome at 10 years is reported of a prospective study of 2 cohorts of total knee arthroplasties treated with (center A) or without (center B) patellar replacement. The same tibiofemoral components were used in all knees. The cohorts were demographically similar. A total of 124 patellae were treated by replacement, and 143 were treated without replacement. The clinical outcome and the patellofemoral revision rates were the same in the 2 cohorts: 1 patient required analgesia for anterior knee pain after replacement, and 1 without replacement required patellar replacement for pain. In the replaced group, patellofemoral survival on a best-case scenario was 100% at 10 years; on a worst-case scenario, 96%. One of the unreplaced patellae had been resurfaced for pain by 10 years. In view of the satisfactory and similar outcomes with and without replacement, we suggest that an appropriate design for the prosthetic trochlea, rather than the replacement or otherwise of the patella, is the main determinant of patellofemoral outcome in total knee arthroplasty. Patella replacement may be optional. Desirable trochlea design features are described.     

髌骨软骨退变分级对保留髌骨型全膝关节置换术疗效的影响

 目的 探讨髌骨软骨退变Outerbridge分级对保留髌骨型全膝关节置换术疗效的影响。方法 对2007年2月至2010年1月因膝关节退变性骨关节炎行保留髌骨型全膝关节置换术的151例进行回顾性分析。男65例,女86例;年龄56～82岁,平均(65±5.0)岁。随访时间2～5年,平均3.5年。术中对髌骨软骨退变分级的评定采用Outerbridge标准,统计末次随访时不同髌骨软骨退变分级患者的满意度及膝前痛发生情况,视觉模拟评分(visual analogue scale,VAS)>3分判定为有膝前痛;比较不同髌骨软骨退变分级患者的美国膝关节学会评分(Knee Society Scale,KSS)及髌骨评分。结果 OuterbridgeⅠ级18例、Ⅱ级36例、Ⅲ级62例、Ⅳ级35例。膝前痛发生率4.0%(6/151),其中轻度疼痛4例、中度2例。无翻修病例,总体满意率96.7%(146/151)。不同髌骨软骨退变分级患者的满意度(H=5.54,P=0.14)、膝前痛发生率(H=0.56, P=0.91)、KSS膝评分(F=1.95, P=0.12)、功能评分(F=2.11,P=0.10)及髌骨评分(F=1.35, P=0.26)的差异均无统计学意义。结论 不同髌骨软骨退变分级患者行保留髌骨型全膝关节置换术后疗效无差异,对退变性骨关节炎患者行全膝关节置换术时无须置换髌骨。