Patella Resurfacing during Total Knee Arthroplasty: Have We Got the Issue Covered?

Background

Management of the patella during total knee arthroplasty (TKA) is controversial. Multiple studies have examined mechanical and clinical results of TKA with native and resurfaced patellae with no clear consensus.

Methods

We surveyed a large cohort of consultant surgeons in a questionnaire based study in order to assess the indications for patella resurfacing and to correlate practice with degree of specialization, experience and volume of procedures performed.

Results

Six hundred and nineteen surgeons were included. The main indication for patella resurfacing was patellofemoral arthritis. The ratio of those who always:sometimes:never resurfaced was 1:2:1 irrespective of experience or volume performed. There was no difference between knee specialists and non-specialists (p = 0.977) or between high and lower volume surgeons (p = 0.826). Senior and high volume surgeons tended to always resurface.

Conclusions

The majority of surgeons only sometimes resurfaced the patella. The number who always and never resurfaced were similar. There was a tendency for more experienced and high volume surgeons to always resurface.     

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.     

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.     

Routine patellar resurfacing using an inset patellar technique

The management of the patella in total knee arthroplasty still causes controversy. Whether or not to resurface the patella in primary total knee arthroplasty remains unclear. In this study we examined 220 consecutive total knee replacements, by a single surgeon, where the patella was routinely resurfaced using the inset technique. All patellae were suitable for resurfacing. Patellar thickness was not altered in 54.5% of patellae. In 97.2% the patella was within 2 mm of the original thickness. There were no significant complications. In this study we have found that the inset technique of patella resurfacing in total knee replacement is a simple and safe resurfacing procedure.     

The Impact of Patellar Resurfacing in Two-Stage Revision of the Infected Total Knee Arthroplasty

Evidence for optimal management of the patellofemoral joint in revision surgery for the infected TKA is limited. We reviewed 69 infected TKAs undergoing two-stage revision. Fifty four patellae were resurfaced, 11 had patelloplasty performed, two were augmented with trabecular metal, one had impaction grafting, and one knee underwent patellectomy. Average follow-up was 4.5 years. The patients that received patellar resurfacing at re-implantation experienced statistically significant improvements in KSS pain score, functional KSS, and patellar score (P < 0.03). One further patient treated with impaction grafting improved significantly in terms of pain and function. Patients treated with patelloplasty, trabecular metal augmentation, or patellectomy did not have significant improvements in clinical or functional outcome. Patient age, use of dynamic vs. static spacer, use of extensor mechanism release, and differences in Charlson index did not seem to statistically affect outcome. We recommend that every effort should be made to minimize patellar bone loss in first stage resection, as inability to resurface the patella at time of reimplantation may adversely affect patient outcome.     

International Rates of Patellar Resurfacing in Primary Total Knee Arthroplasty, 2004-2014

Background

Patella resurfacing is performed in >80% of primary total knee arthroplasties (TKAs) in the United States, yet far fewer patellae are resurfaced internationally. Recent registry data have begun to question the long-held belief that patellar resurfacing yields lower revision rates. Multiple current meta-analyses have not shown a difference in patient satisfaction, anterior knee pain, or knee society scores based on patellar resurfacing.

Patellar resurfacing in total knee arthroplasty leads to better isokinetic performance

BackgroundFor decades there have been concerns about patellar resurfacing (PR) in total knee arthroplasty (TKA) and the individual preference of the surgeon is still the main determinant of whether or not resurfacing is applied. According to preference, surgeons can be categorized in 3 main groups of those who usually, selectively, or rarely resurface. The aim of this prospective, randomized, controlled study was to compare the isokinetic performance and clinical outcome of TKAs with PR and without PR.MethodsA total of 50 patients scheduled to undergo TKA for primary osteoarthritis of the knee were randomly assigned to either the PR or non-PR groups. There were no significant differences between the groups in respect of age, BMI, gender and preoperative Knee Society Score (KSS) and isokinetic performance. Patients were evaluated at postoperative 3, 6, and 12 months with KSS and at 6 months and 1 year with isokinetic measurements.ResultsThe PR group had a higher mean score, especially in the functional component of KSS, but the difference was not statistically significant. Knee extension peak torque was significantly higher in the PR group at 6 months (p = 0.029) and 1 year (p = 0.004) postoperatively. There were no significant differences between the groups in respect of knee flexion peak torque values following TKA.ConclusionsThe results of this study demonstrated that PR during TKA is associated with better isokinetic performance and higher knee scores. These results support routine/usually resurfacing of the patella. For surgeons who selectively resurface the patella, the advantage of better isokinetic performance may be taking into consideration in favor of resurfacing the patella where they are undecided.Level of evidenceLevel I, therapeutic study.     

Biomechanical Study of Patellar Component Fixation with Varying Degrees of Bone Loss

BackgroundThe decision as to whether or not to resurface the patella in revision total knee arthroplasty (TKA) is affected by the amount of patellar bone stock remaining; however, the impact of the cancellous bone status on patellar component fixation has not been studied. Therefore, we conducted a biomechanical study of patellar component fixation with varying degrees of cancellous bone loss.MethodsSixty pairs of cadaveric patellae were randomly assigned between 3 groups and prepared in similar manner to a TKA with the standard 3-hole configuration. A control patella and an experimental patella were designated in each pair. To simulate bone loss in the experimental patellae, 1, 2, and 3 of the standard drill holes were uniformly enlarged to 12 mm in group 1, group 2, and group 3, respectively. Afterward, an all-polyethylene patellar component was cemented to each patella, as done intraoperatively. Patellar components were then sheared off using a materials testing system. The resulting mean offset yield force was analyzed within each group using paired t-tests.ResultsThe mean offset yield force for the control patellae was greater than the experimental patellae in group 1. In groups 2 and 3, the experimental patellae produced a greater mean offset yield force than the control patellae. Comparison within each group did not demonstrate a statistically significant difference.ConclusionBone loss with enlargement of the patellar fixation holes, as is frequently seen in revision TKA, with holes up to 12 mm, does not significantly decrease patellar component fixation shear strength in this biomechanical cadaveric study.     

Patellar resurfacing in total knee arthroplasty

Routine patella resurfacing in total knee arthroplasty has been debated for decades. The early total knee designs and surgical techniques lead to a high complication rate following patellar resurfacing. This lead to many surgeons abandoning this practice and either leaving the patella unresurfaced routinely or selectively resurfacing. Modern day randomized control trials and meta-analyses of these trials reveal a higher incidience of anterior knee pain and a resultant higher reoperation rate in nonresurfaced patellae. We argue that with modern day designs and surgical techniques, there is a low complication rate to resurfacing and little downside to resurfacing.     

Patellar resurfacing versus nonresurfacing in total knee arthroplasty: A meta-analysis of randomised controlled trials

Purpose

Patella resurfacing or nonresurfacing in total knee arthroplasty remains controversial. The aim of this study was to evaluate the efficacy of patellar resurfacing through an evaluation of the current literature.

Methods

We carried out a meta-analysis of randomised controlled trials comparing total knee arthroplasties performed with and without patellar resurfacing. Outcomes of reoperation, anterior knee pain and knee scores were analysed.

Results

Fourteen trials assessing 1,725 knees were eligible. The absolute risk of reoperation was reduced by 4 % (95 % confidence interval, 2–6 %) in the patellar resurfacing arm (between-study heterogeneity, P = 0.05, I² = 42 %), implying that one would have to resurface 25 patellae (95 % confidence interval, 17–50 patellae) in order to prevent one reoperation. There was no difference between the two groups in terms of anterior knee pain, knee pain score, Knee Society score and knee function score. But in the studies followed up for a mean time of not less than five years, a difference was found between the two arms in Knee Society scores (RR = 2.14, 95 % confidence interval, 0.76–3.52; P = 0.002).

Conclusions

The available evidence indicates that patellar resurfacing reduces the risk of reoperation after total knee arthroplasty. Patellar resurfacing patients may make a difference in long-term follow-up (five or more 5 years) of Knee Society scores. In other aspects, the benefit of patellar resurfacing is limited. Additionally, more carefully and scientifically designed randomised controlled trials are required to further prove the claim.     

Patellar resurfacing in total knee arthroplasty. A meta-analysis

BACKGROUND: Patellar resurfacing during total knee arthroplasty remains controversial. We aimed to evaluate the effectiveness of this technique through an evaluation of the current literature. METHODS: We performed a meta-analysis of randomized controlled trials comparing total knee arthroplasties performed with and without patellar resurfacing. Outcomes of interest included the number of reoperations, the prevalence of postoperative anterior knee pain, and the improvement in various knee scores. RESULTS: Ten trials assessing 1223 knees were eligible. The absolute risk of reoperation was reduced by 4.6% (95% confidence interval, 1.9% to 7.3%) in the patellar resurfacing arm (between-study heterogeneity, p < 0.01; I(2) = 60%), implying that one would have to resurface twenty-two patellae (95% confidence interval, fourteen to fifty-two patellae) in order to prevent one reoperation. Patellar resurfacing reduced the absolute risk of postoperative anterior knee pain by 13.8% (95% confidence interval, 6.4% to 21.2%), implying that one would have to resurface seven patellae (95% confidence interval, five to sixteen patellae) in order to prevent one case of postoperative anterior knee pain. Only four trials provided adequate data for a quantitative synthesis of the changes in the various knee scores; on the basis of those four trials, there was no difference in the mean improvement in the knee scores (standardized mean difference, 0.03; 95% confidence interval, -0.50 to 0.56). CONCLUSIONS: The available evidence indicates that patellar resurfacing reduces the risks of reoperation and anterior knee pain after total knee arthroplasty. The observed effects are clinically important despite their modest magnitude. Additional, carefully designed randomized trials are required to strengthen this claim.     

Patellar Resurfacing in Total Knee Arthroplasty: A Cost-Effectiveness Analysis

Background

This study estimates the cost-effectiveness of patellar resurfacing in total knee arthroplasty (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。     

Is Selectively Not Resurfacing the Patella an Acceptable Practice in Primary Total Knee Arthroplasty?

Background

To resurface or not to resurface the patella remains a controversy in total knee arthroplasty (TKA). The purpose of this study was to assess the long-term outcomes associated with selectively not resurfacing the patella.

Influence of Patellar Morphology Classified by Wiberg Classification on Knee Joint Function and Patellofemoral Tracking After Total Knee Arthroplasty Without Patellar Resurfacing

BackgroundTo evaluate the influence of patellar morphology on knee joint function and patellofemoral tracking in patients with primary osteoarthritis after total knee arthroplasty (TKA) without patellar resurfacing.MethodsWe performed a retrospective study of 156 patients with primary osteoarthritis who underwent TKA without patellar resurfacing from April 2018 to July 2019. As per Wiberg classification, patients were divided into Wiberg type I (group A, n = 38), II (group B, n = 88), and III (group C, n = 30) groups. The clinical data, postoperative follow-up data, and radiological data between three groups were compared.ResultsThere was no statistically significant difference in the HSS score and Feller score between the three groups before surgery and at each follow-up point after surgery (P > .05). At the last follow-up, there were no significant differences in the height and relative thickness of the patella between the three groups (P > .05). However, the incidence of anterior knee pain was significantly higher in group C than in the group B (P < .05). The patellar tilt angle was significantly larger in group C than in the groups A and B (both P < .05). The patellar facet angle was significantly larger in group A than in group B and C, which was also significantly larger in group B than in group C (both P < .05).ConclusionPatients with three different morphologic types of the patella both exhibited improved knee joint function after TKA, however, patients with Wiberg type Ⅲ patella were more prone to have poor patellofemoral tracking and anterior knee pain after surgery.     

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.     

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.     

Selective Patella Resurfacing in Contemporary Cruciate Retaining and Substituting Total Knee Arthroplasty: A Matched Cohort Analysis

BackgroundLeaving the patella unresurfaced in total knee arthroplasty (TKA) is increasing due to modern patella-friendly implants, awareness that complications are not uncommon with resurfacing, and knowledge that historical studies were scientifically confounded. This study examined the effect of selective patellar resurfacing on patient-reported outcome measures (PROMs) using modern implants and techniques in cohorts rigorously matched for demographics and osteoarthritis severity.MethodsA total of 166 TKAs performed without patellar resurfacing were case-control matched to 166 TKAs with patella resurfacing. Case-control matching was based on demographics, American Society of Anesthesiology Physical Status, comorbidities, and osteoarthritis severity. No significant differences were observed between cohorts for demographics (P ≥ .347), comorbidities (P ≥ .443), or radiographic osteoarthritis severity (P ≥ .078). Radiographic alignment and prospectively collected PROMs were evaluated preoperatively and at latest clinical follow-up.ResultsPreoperatively, patellar tilt was less for the unresurfaced patella group (3 versus 4°, P = .003); however, postoperative patellar tilt was not different (3 versus 3°, P = .225). At a mean of 2.1 years follow-up (range, 1 to 7), University of California Los Angeles Activity Level was significantly higher for the unresurfaced patella group (6.3 versus 5.5, P = .002), but the mean group difference did not reach a minimal clinically important difference. There were no other significant differences in PROMs or reoperation rates between cohorts (P ≥ .135).ConclusionIn contemporary cruciate retaining and substituting TKA designs, not resurfacing the patella in select patients may achieve comparable PROMs and re-operation rates; and potentially greater activity level compared to patella resurfacing at early follow-up.Level of EvidenceIII.     

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.     

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.