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.     

旋转平台与固定平台全膝关节置换术的对比研究及髌骨置换与否对疗效的影响

目的评估旋转平台和固定平台假体全膝关节置换(TKA)两型假体间的疗效有无差异及髌骨置换与否对疗效的影响。方法选取同一医师施行的78侧初次TKA进行回顾。术前诊断包括骨关节炎、类风湿性关节炎等。施行固定平台TKA手术的患者共30侧,14侧置换髌骨;施行旋转平台TKA手术的共48侧,36侧置换髌骨。术前和术后随访行膝HSS评分、测量关节伸直角度和屈曲角度,以比较两型假体TKA疗效;比较髌骨置换组与未置换组TKA疗效;在髌骨置换组与未置换组中,分别比较固定平台TKA和旋转平台TKA的疗效。结果成功随访76侧,平均25.2个月。旋转平台组术后HSS评分、伸直角度与固定平台组间的差异无统计学意义,前者术后的屈曲角度(112.0±11.5)°优于固定平台组间的差异有统计学意义(t=3.270,P0.01)。髌骨未置换组术后HSS评分、伸直角度与髌骨置换组(102.5±15.1)°组间差异有统计学意义(t=2.469,P0.05;t=3.747,P0.01),术后屈曲角度与后者间的差别无统计学意义。髌骨未置换组中,旋转平台TKA与固定平台TKA的术后HSS评分、屈曲角度无差异,伸直角度差别无临床意义。髌骨置换组中,旋转平台TKA术后HSS评分、伸直角度与固定平台TKA间的差异无统计学意义,前者术后的屈曲角度(112.9±13.0)°与后者术后的屈曲角度(96.7±18.4)°比较差异有统计学意义(t=2.838,P0.05)。结论旋转平台假体与固定平台假体TKA术后总体疗效相似,旋转平台假体能够更好地改善关节屈曲角度;置换髌骨并不能更好地改善膝关节功能。     

Routine patellar resurfacing: a viable option

The literature on routine patellar resurfacing documents that the rate of anterior knee pain after TKA is the same whether the patella is resurfaced or unresurfaced. The complication rate is different in these groups. In patients in whom the native patella is left, the rate of reoperation is approximately 10%. However, when correct surgical technique is used, the rate of patellar complications after routine resurfacing is negligible. Although design modifications have helped reduce patellar complications, the surgeon is the most important variable. As long as good technique is used, routine patellar resurfacing has been proven to produce the best results in TKA.     

Similar patient-reported outcomes and performance after total knee arthroplasty with or without patellar resurfacing: A randomized study of 74 patients with 6 years of follow-up

Background and purpose — Knee pain after total knee arthroplasty (TKA) is not uncommon. Patellar retention in TKA is one cause of postoperative knee pain, and may lead to secondary addition of a patellar component. Patellar resurfacing in TKA is controversial. Its use ranges from 2% to 90% worldwide. In this randomized study, we compared the outcome after patellar resurfacing and after no resurfacing. Patients and methods — We performed a prospective, randomized study of 74 patients with primary osteoarthritis who underwent a Triathlon CR TKA. The patients were randomized to either patellar resurfacing or no resurfacing. They filled out the VAS pain score and KOOS questionnaires preoperatively, and VAS pain, KOOS, and patient satisfaction 3, 12, and 72 months postoperatively. Physical performance tests were performed preoperatively and 3 months postoperatively. Results — We found similar scores for VAS pain, patient satisfaction, and KOOS 5 subscales at 3, 12, and 72 months postoperatively in the 2 groups. Physical performance tests 3 months postoperatively were also similar in the 2 groups. No secondary resurfacing was performed in the group with no resurfacing during the first 72 months Interpretation — Patellar resurfacing in primary Triathlon CR TKA is of no advantage regarding pain, physical performance, KOOS 5 subscales, or patient satisfaction compared to no resurfacing. None of the patients were reoperated with secondary addition of a patellar component within 6 years. According to these results, routine patellar resurfacing in primary Triathlon TKA appears to be unnecessary.     

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.     

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 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.     

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。     

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.     

髌骨软骨破坏程度对保留髌骨的全膝关节置换术疗效的影响

目的 探讨髌骨软骨破坏程度对保留髌骨的全膝关节置换术疗效的影响.方法 2002年1月至2006年5月行全膝关节置换术163例244膝,根据术中观察到的髌骨软骨破坏程度将患者分为轻度、中度、重度软骨破坏三组.所有手术均不置换髌骨.术后随访88例133膝,轻度组42膝,中度组43膝,重度组48膝.采用美国膝关节学会评分(Knee Society Score,KSS)系统(包括膝评分和膝功能评分)和膝前痛评分系统对三组疗效进行评估.结果 随访48～102个月,平均72个月.KSS膝评分和膝功能评分从术前(35.1±5.4)分和(19.2±9.8)分分别提高到(91.7±5.6)分和(83.7±17.5)分.三组KSS膝评分从术前(34.7±6.2)分、(36.5±5.2)分、(35.3±6.2)分分别提高至(92.6±4.5)分、(90.5±6.7)分、(91.9±5.9)分;膝功能评分从术前(14.2±8.6)分、(16.5±7.4)分、(17.0±7.5)分分别提高至(86.6±12.6)分、(82.0±17.2)分、(82.8±21.1)分.三组术后膝评分和膝功能评分的差异均无统计学意义.术后膝前痛的发生率为11.3%(15/133),轻度、中度、重度软骨破坏组分别为11.9%(5/42)、11.6%(5/43)、10.4%(5/48),差异无统计学意义.结论 全膝关节置换术后疗效及膝前痛的发生率与术前髌骨软骨破坏程度无关,髌骨软骨破坏程度不是全膝关节置换术中置换髌骨的可靠依据.

Abstract：

Objective To determine whether there was any correlation between the degree of degenerative changes in the patellar cartilage and the clinical outcome after TKA without patellar resurfacing.Methods A clinical study was performed on 133 knees of 88 patients that underwent TKA without patellar resurfacing from January 2002 to May 2006. According to the degenerative condition of the patellar cartilage,patients was classified as mild group, moderate group, and severe group. Pre- and post-operative evaluations were performed using the knee and function scores of the Knee Society Clinical Rating System (KSS) and Anterior Knee Pain Rating. Results The duration of follow-up was 72 months (range 48-102). The overall knee score of KSS in all patients were improved from 35.1±5.4 preoperatively to 91.7±5.6 postoperatively,and function score of KSS from 19.2±9.8 preoperatively to 83.7±17.5 postoperatively. The mean knee scores of KSS were improved from 34.7±6.2, 36.5±5.2 and 35.3±6.2 preoperatively to 92.6±4.5, 90.5±6.7 and 91.9±5.9 in mild, moderate, and severe group postoperatively, respectively. The mean function scores of KSS were improved from 14.2±8.6, 16.5±7.4 and 17.0±7.5 postoperatively to 86.6±12.6, 82.0±17.2 and 82.8±21.1 in mild, moderate, and severe group postoperatively, respectively. There was no difference among all groups with regard to the postoperative knee scores and function scores of KSS. The prevalence of anterior knee pain was 11.3% in all, and 11.9% in mild group, 11.6% in moderate group and 10.4% in severe group. There was no difference among all groups with regard to the anterior knee pain. Conclusion The clinical outcome and anterior knee pain after TKA without patellar resurfacing was not correlated with the severity of degenerative changes in the patellar cartilage. The degree of degenerative condition of the patellar cartilage is not indication for patellar resurfacing.     

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.     

Asymmetric patella resurfacing in total knee arthroplasty

Three hundred consecutive primary, cemented, condylar total knee arthroplasties (TKAs) were reviewed for the presence of asymmetric patella resurfacing using a postoperative Merchant or sunrise patellar radiograph. Twenty-one knees in 14 patients were found to have the patella asymmetrically resurfaced. Asymmetric resurfacing typically involved the inadvertent preferential resurfacing of the lateral facet with underresection of bone from the medial patellar facet. All patients underwent follow-up for a minimum of 5 years, with a mean follow-up of 7.5 years. Of the 21 knees, 3 revisions were required for patellar complications. One patellar component was loose on radiographs and there was marked patellofemoral pain in 6 knees. Overall, 11 of 21 knees (52%) underwent revision or were recommended for revision for patellar complications or had anterior knee pain that limited activities. Inadvertent asymmetric patella resurfacing using the kinematic condylar implant adversely affects the outcome after TKA.     

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。     

髌骨置换与否对全膝关节置换效果的影响

目的评价髌骨置换与否对全膝关节表面置换的影响。方法对2000年1月至2001年6月间行膝关节表面置换的165例病人随机分为髌骨置换组和不置换组。置换组均采用同一种膝关节假体系统，由同组医生完成，术前和随访时评价HSS评分、髌骨评分和髌骨适合角、髌骨高度等影像学结果。所有评价均采用双盲的方式。结果在HSS评分和髌骨评分方面，两组无统计学差异。影像学评价两组无统计学差异。髌骨置换组的手术时间明显长于非置换组。结论对于骨关节炎病人，不置换和置换髌骨临床效果相当，影像学表现无明显区别。但置换组的手术时间更长。不论置换与否，手术时应注意对下肢力线的矫正。     

Patellar Denervation Reduces Postoperative Anterior Knee Pain After Patellar Resurfacing Total Knee Arthroplasty: A Randomized Controlled Trial

BackgroundThe benefit of patellar denervation (PD) in patellar resurfacing total knee arthroplasty (TKA) is still debatable. This prospective, randomized controlled trial investigated whether circumferential PD should be performed in patellar resurfacing TKA.MethodsA total of 241 patients who underwent unilateral TKA were randomized into PD or non-PD groups. Incidence, intensity, and presentation time of anterior knee pain (AKP) and clinical outcomes were evaluated at 3, 6, 9, 12, 18, and 24 months postoperatively.ResultsThe incidence of AKP was significantly lower in the PD group (6.4% vs 16.2%, P = .032). The intensity of AKP and patient satisfaction scores were significantly better in the PD group at 3 months but not after 3 months. The presentation time of AKP mostly occurs at 3 months after surgery. The Knee Society score, range of motion, Oxford score, patellar score, activity of daily living score, and visual analog scale of overall knee pain were not significantly different between the two groups during the follow-up period.ConclusionGiven that PD can improve AKP and patient satisfaction at an early period postoperatively without jeopardizing clinical outcomes at no additional cost, this inexpensive procedure readily available in nearly every operation room is strongly recommended during primary TKA with patellar resurfacing.     

全膝关节置换术中髌骨置换与否对早期疗效及膝前痛的影响

 目的 探讨全膝关节置换术中髌骨置换与否对早期疗效及膝前痛发生率的影响。方法 2010年6月至2011年6月拟行全膝关节置换术患者100例,随机分为两组：髌骨置换组43例50膝,髌骨未置换组57例66膝。比较术后6个月、12个月两组患者的西安大略和麦克马斯特大学(West Ontario and McMaster Universities,WOMAC)骨关节炎指数、美国膝关节外科协会(Knee Surgery Society,KSS)膝评分和功能评分、膝前痛视觉模拟评分(visual analogue scale,VAS)。结果 髌骨置换组与髌骨未置换组患者术后膝前痛VAS评分均较术前明显降低,两组间VAS评分及膝前痛发生率的差异无统计学意义。WOMAC骨关节炎指数6个月分别为28.8±11.2和18.6±7.2、术后12个月分别为20.7±6.2和16.0±5.5,KSS膝评分6个月分别为(87.0±8.3)分和(90.9±7.2)分、术后12个月分别为(84.2±10.6)分和(88.8±9.2)分,KSS功能评分术后6个月分别为(86.6±21.6)分和(84.9±16.5)分、术后12个月分别为(85.2±16.4)分和(91.0±10.0)分,组间差异均无统计学意义。髌骨轴位X线片示髌骨与股骨假体滑车吻合度良好,无不稳及脱位表现。术后1年内无翻修、髌骨表面再置换病例。结论 全膝关节置换术对改善因骨关节炎或类风湿关节炎导致的膝关节疼痛、功能受限有效;髌骨置换与否对术后短期疗效及膝前痛发生率没有影响。     

A meta-analysis of patellar replacement in total knee arthroplasty

From individual randomized studies it is unclear whether the patella should be replaced during total knee replacement. We did a meta-analysis to provide quantitative data to compare patellar resurfacing with nonresurfacing during total knee arthroplasty. Only randomized, controlled trials reported between January 1966 and August 2003 comparing patellar replacement with patella retention were included for a total of 12 studies. Two reviewers assessed trial quality and extracted data from papers. The outcomes identified were reoperations for patellar problems, anterior knee pain, knee scores, stair climbing, and patient satisfaction. The resurfaced patella performed better, and we found an increased relative risk (defined by the ratio of the risk of the event in the resurfaced group on the risk of the event in the nonresurfaced group) for reoperation, for significant anterior knee pain, and for significant pain during stair climbing when the patella was left unresurfaced. No differences were observed between the two groups for International Knee Society function score, Hospital for Special Surgery score, and for patient satisfaction. Despite these general findings, forming a definitive conclusion is difficult because many confounding factors, such as component design, surgeon experience, and technical aspects of the surgery, might influence the result in a patient.     

Early PROMs Following Total Knee Arthroplasty—Functional Outcome Dependent on Patella Resurfacing

Patella resurfacing during primary total knee arthroplasty (TKA) remains controversial. Variation in published results for patella resurfacing may potentially be explained by differences in design between TKA brands. We interrogated NJR-PROMs data to ascertain whether there is an early functional benefit to resurfacing the patella, both overall and for each of the five most popular primary knee designs through use of the Oxford Knee Score. A total of 8103 resurfaced TKAs and 15,290 nonresurfaced TKAs were studied. There was a large variation in the proportion of knees undergoing patella resurfacing by brand (Nexgen = 16% versus Triathlon = 52%). Patellar resurfacing did not significantly influence the magnitude of improvement in overall knee function or anterior knee-specific function irrespective of TKA brand or for cruciate retaining versus sacrificing designs.     

The Outcome of Total Knee Arthroplasty With and Without Patellar Resurfacing up to 17 Years: A Report From the Australian Orthopaedic Association National Joint Replacement Registry

BackgroundPatellar resurfacing in total knee arthroplasty (TKA) remains a controversial issue after more than 4 decades of TKA. Despite a growing body of evidence from registry data, resurfacing is still based largely on a surgeon’s preference and training. The purpose of this study is to provide long-term outcomes for patellar resurfaced compared to when the patella is not resurfaced.MethodsData from the Australian Orthopaedic Association National Joint Replacement Registry (1999-2017) were used for this study. The analysis included 570,735 primary TKAs undertaken for osteoarthritis. Hazard ratios (HRs) and 17-year cumulative percent revision rates were used to compare revision rates between 4 subgroups: minimally stabilized (MS) patellar resurfacing, posterior stabilized (PS) patellar resurfacing, MS unresurfaced, and PS unresurfaced patella. Additional analyses of the patellar implant type and a comparison of inlay and onlay patellar resurfacing were also performed.ResultsFor all primary TKA, procedures where the patella was not resurfaced have a higher rate of revision compared to procedures where the patella was resurfaced (HR, 1.31; confidence interval, 1.28-1.35; P < .001). Unresurfaced PS knees have the highest cumulative percent revision at 17 years (11.1%), followed by MS unresurfaced (8.8%), PS resurfaced (7.9%), and MS resurfaced (7.1%). Inlay patellar resurfacing has a higher rate of revision compared to onlay patellar resurfacing (HR, 1.27; confidence interval, 1.17-1.37; P < .001).ConclusionResurfacing the patella reduces the rate of revision for both MS and PS knees. MS knees with patellar resurfacing have the lowest rate of revision. Onlay patella designs are associated with a lower revision rate compared to inlay patella designs.     

The role of patellar resurfacing in total knee arthroplasty

The ideal treatment of the patella in primary total knee arthroplasty (TKA) for osteoarthritis (OA) remains unclear. Although data exist in the literature to support either resurfacing or not resurfacing the patella, evidence continues to emerge that unresurfaced patellas deteriorate with time. Recent prospective, randomized studies also favor patellar resurfacing over retaining the native patella, reporting reoperation rates to convert unresurfaced to resurfaced patellas exceeding those for complications after patellar resurfacing. In addition, the incidence of residual patellofemoral pain after secondary resurfacing is substantially higher than when patellofemoral resurfacing is done primarily. Patient selection criteria are critical in the decision-making process. Patellofemoral complications, the greatest argument against resurfacing, have been diminished with improved surgical techniques and implant design.