The efficacy of circumpatellar electrocautery in reducing the incidence of post-operative anterior knee pain is unknown. We conducted a single-centre, outcome-assessor and patient-blinded, parallel-group, randomised, controlled trial to compare circumpatellar electrocautery with no electrocautery in total knee replacement in the absence of patellar resurfacing. Patients requiring knee replacement for primary osteoarthritis were randomly assigned circumpatellar electrocautery (intervention group) or no electrocautery (control group). The primary outcome measure was the incidence of anterior knee pain. A secondary measure was the standardised clinical and patient-reported outcomes determined by the American Knee Society scores and the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index. A total of 131 knees received circumpatellar electrocautery and 131 had no electrocautery. The overall incidence of anterior knee pain at follow-up at one year was 26% (20% to 31%), with 19% (12% to 26%) in the intervention group and 32% (24% to 40%) in the control group (p = 0.02). The relative risk reduction from electrocautery was 40% (9% to 61%) and the number needed to treat was 7.7 (4.3 to 41.4). The intervention group had a better mean total WOMAC score at follow-up at one year compared with the control group (16.3 (0 to 77.7) versus 21.6 (0 to 76.7), p = 0.04). The mean post-operative American Knee Society knee scores and function scores were similar in the intervention and control groups (knee score: 92.4 (55 to 100) versus 90.4 (51 to 100), respectively (p = 0.14); function score: 86.5 (15 to 100) versus 84.5 (30 to 100), respectively (p = 0.49)). Our study suggests that in the absence of patellar resurfacing electrocautery around the margin of the patella improves the outcome of total knee replacement.

In the absence of patellar resurfacing, we have previously shown that the use of electrocautery around the margin of the patella improved the one-year clinical outcome of total knee replacement (TKR). In this prospective randomised study we compared the mean 3.7 year (1.1 to 4.2) clinical outcomes of 300 TKRs performed with and without electrocautery of the patellar rim: this is an update of a previous report. The overall prevalence of anterior knee pain was 32% (95% confidence intervals [CI] 26 to 39), and 26% (95% CI 18 to 35) in the intervention group compared with 38% (95% CI 29 to 48) in the control group (chi-squared test; p = 0.06). The overall prevalence of anterior knee pain remained unchanged between the one-year and 3.7 year follow-up (chi-squared test; p = 0.12). The mean total Western Ontario McMasters Universities Osteoarthritis Indices and the American Knee Society knee and function scores at 3.7 years' follow-up were similar in the intervention and control groups (repeated measures analysis of variance p = 0.43, p = 0.09 and p = 0.59, respectively). There were no complications. A total of ten patients (intervention group three, control group seven) required secondary patellar resurfacing after the first year. Our study suggests that the improved clinical outcome with electrocautery denervation compared with no electrocautery is not maintained at a mean of 3.7 years' follow-up.

When secondary patellar resurfacing is performed, a uniformly and widely used scoring system that is validated for anterior knee pain caused by a retropatellar degeneration will give more insight into the results of this procedure. The cause of anterior knee pain following total knee arthroplasty (TKA) is not always related to the patella itself. Other causes have been identified, such as an insufficient posterior cruciate ligament in the case of a posterior cruciate-retaining TKA or an internally rotated femoral and/or tibial component. Treatment of anterior knee pain following primary TKA with secondary patellar resurfacing is a controversial procedure with uncertain outcomes. The purpose of this study is to systematically review the available peer-reviewed literature on patient satisfaction and functional outcomes of secondary resurfacing. The authors performed a systematic computerized database search of the Cochrane Database of Systematic Reviews, MEDLINE, and EMBASE in October 2014. The quality of the included studies was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. A total of 15 articles met the inclusion criteria. In total, 148 (64%) of 232 patients were satisfied with the outcomes of secondary patellar resurfacing. A statistically significant improvement in knee scores was noted in all 9 studies that reported functional outcomes, although no clinically significant improvement in knee scores was observed. Reported complications include infections and impaired wound healing, patellar instability, and patellar fracture. Because the available evidence is of generally low quality, the results of this systematic review only support a weak recommendation for secondary patellar resurfacing if patient satisfaction and clinically important improvement of functional outcomes are the desired endpoints. [Orthopedics.2016; 39(5):e850-e856.].