For Doctors in a Hurry
- Clinicians lack consensus on whether patellar resurfacing during total knee arthroplasty improves patient outcomes or reduces anterior knee pain.
- The researchers analyzed 1,764 propensity-matched patients, comparing 1,176 who underwent patellar resurfacing against 588 who did not receive it.
- Postoperative complication rates and most patient-reported outcome measures showed no statistically significant differences between the two study groups.
- The authors concluded that patients achieve comparable clinical results with modern implants regardless of whether the patella is resurfaced.
- These findings suggest that surgeons may safely omit patellar resurfacing without compromising functional recovery or increasing the risk of complications.
The Patellofemoral Conflict in Total Knee Arthroplasty
Total knee arthroplasty remains the definitive intervention for end-stage osteoarthritis, yet postoperative dissatisfaction persists in a significant subset of patients [1]. A primary driver of this dissatisfaction is residual anterior knee pain, which affects between 4% and 40% of patients following the procedure [2]. To mitigate this, surgeons frequently debate the necessity of patellar resurfacing, a practice intended to optimize patellofemoral mechanics by replacing the articular surface of the patella with a polyethylene component, though the procedure carries its own risk of complications [3]. While some evidence suggests resurfacing reduces the need for secondary operations, the impact on overall functional scores and patient-reported quality of life remains inconsistent across the literature [4, 5]. This clinical uncertainty has led to a lack of consensus on whether to routinely resurface, selectively resurface, or leave the native patella intact [6]. A new propensity-matched analysis now examines how these intraoperative decisions influence patient-perceived outcomes and complication profiles.
Methodological Rigor Through Propensity Matching
Historically, clinical decisions regarding patellar resurfacing have been guided by data from studies often limited by small sample sizes and a lack of propensity matching, which is a statistical technique used to balance treatment groups by matching patients with similar characteristics to reduce selection bias. To address these limitations, researchers analyzed a large institutional database comprising 5,197 consecutive patients who underwent total knee arthroplasty. This high volume of data allowed for a more robust evaluation of patient-reported outcome measures than was possible in earlier, smaller cohorts. The researchers employed a 1:2 propensity match to ensure that the comparison between resurfaced and non-resurfaced groups was as rigorous as possible. Patients were matched based on several critical clinical variables, including age, body mass index, sex, race, comorbidities, and the specific implants used during the procedure. This process resulted in a final matched cohort of 1,176 resurfaced patients and 588 non-resurfaced patients. By utilizing this matching ratio, the study effectively controlled for potential confounding factors that might otherwise skew the assessment of surgical outcomes. The success of this statistical balancing was evidenced by the fact that there were no demographic differences between the matched groups (P > 0.05). This parity is essential for clinicians to trust that any observed differences, or lack thereof, in postoperative recovery and complication rates are attributable to the resurfacing decision itself rather than underlying patient characteristics. By establishing such a closely aligned baseline, the study provides a clearer picture of how patellar management influences the long-term functional status of the knee.
Evaluating Functional Recovery and Patient Perception
The researchers assessed surgical success through several quantitative lenses, focusing on mean patient-reported outcome measure (PROM) scores and delta scores, which represent the numerical difference between a patient's pre- and postoperative scores. To determine if these changes translated into real-world benefits for the patient, the study utilized the minimal clinically important difference (MCID). The minimal clinically important difference is defined as the smallest change in a treatment outcome that a patient would identify as important or beneficial, providing a threshold to distinguish between statistical significance and clinical relevance in daily life. Analysis of the baseline data showed that the preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) Global Health Physical scores, a standardized tool for assessing general physical well-being, were 42.6 in the non-resurfaced group compared to 41.8 in the resurfaced group (P = 0.0414). Following the intervention, the postoperative Knee Injury and Osteoarthritis Outcome Score Physical Function Short Form (KOOS-PS), which specifically measures knee-related functional limitations, was 73.2 in the non-resurfaced group versus 71.2 in the resurfaced group (P = 0.0299). While these specific metrics reached statistical significance, the higher scores in the non-resurfaced cohort suggest that resurfacing did not provide a superior functional advantage. Furthermore, the narrow margins between these values often fall below the threshold of what patients perceive as a meaningful change in their daily physical function. Beyond these specific metrics, the study found a high degree of parity across all other functional assessments. All other absolute PROM scores and delta scores were similar across groups (P > 0.05), indicating that the trajectory of recovery was nearly identical regardless of patellar management. Crucially, when evaluating the impact on individual patient lives, the proportions of clinically meaningful improvement, no change, and worsening were similar between groups (P > 0.05). These findings suggest that the decision to resurface the patella does not significantly alter the likelihood of a patient achieving a successful functional outcome or experiencing a decline in knee health following total knee arthroplasty.
Clinical Implications for Modern Arthroplasty
The decision to resurface the patella remains one of the most debated technical aspects of total knee arthroplasty, yet current practice patterns show a strong preference for the procedure. Patellar resurfacing is performed in up to 87% of total knee arthroplasties in the United States, reflecting a widespread clinical effort to mitigate postoperative complications. The primary theoretical benefit of this intervention is the reduction of anterior knee pain, a common source of patient dissatisfaction following surgery. Despite its prevalence, there are currently no established best practices for patellar resurfacing in primary total knee arthroplasty, leaving surgeons to rely on institutional preference or individual clinical judgment rather than standardized guidelines. This analysis provides evidence that the routine use of resurfacing may not offer the protective benefits often attributed to it. When examining safety profiles, the researchers found that postoperative complication rates were comparable between the resurfaced and non-resurfaced groups (P > 0.05). This parity in adverse events suggests that omitting resurfacing does not inherently increase the risk of surgical failure or secondary complications. Ultimately, the study suggests that patients achieve similar outcomes with modern implants regardless of patellar resurfacing, indicating that contemporary prosthetic designs may effectively manage patellofemoral mechanics without the need for routine patellar replacement. For the practicing surgeon, these data support the safety of selective resurfacing or patellar retention, provided that the femoral and tibial components are positioned to optimize tracking.
References
1. Joseph R, Tijare C, Boksh K, et al. Combined partial knee arthroplasty versus total knee arthroplasty: A systematic review and meta-analysis of randomised control trials.. Journal of Orthopaedics. 2026. doi:10.1016/j.jor.2026.02.018
2. Feng H, Feng M, Cheng J, Zhang X, Tao H. Meta-analysis of factors influencing anterior knee pain after total knee arthroplasty.. World journal of orthopedics. 2024. doi:10.5312/wjo.v15.i2.180
3. Teel AJ, Esposito J, Lanting B, Howard J, Schemitsch E. Patellar Resurfacing in Primary Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials.. Journal of Arthroplasty. 2019. doi:10.1016/J.ARTH.2019.07.019
4. Teel AJ, Esposito JG, Lanting BA, Howard JL, Schemitsch EH. Patellar Resurfacing in Primary Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials.. The Journal of arthroplasty. 2019. doi:10.1016/j.arth.2019.07.019
5. Grela M, Barrett MC, Kunutsor SK, Blom A, Whitehouse MR, Matharu GS. Clinical effectiveness of patellar resurfacing, no resurfacing and selective resurfacing in primary total knee replacement: systematic review and meta-analysis of interventional and observational evidence. BMC Musculoskeletal Disorders. 2022. doi:10.1186/s12891-022-05877-7
6. Boon A, Barnett E, Culliford L, et al. The clinical and cost-effectiveness of elective primary total knee replacement with PAtellar Resurfacing compared to selective patellar resurfacing: a pragmatic multicentre randomized controlled Trial (PART).. Bone & joint open. 2024. doi:10.1302/2633-1462.56.BJO-2023-0154
