Patella Denervation With Circumferential Electrocautery in Primary Knee Arthroplasty: A Randomized Controlled Trial

Background: The aim of this study was to investigate the clinical effectiveness of patella rim electrocautery “denervation” versus no denervation in patients undergoing total knee arthroplasty (TKA).

Methods: We conducted a single-center, double-blind randomized controlled trial. Patients aged 40 years or older, due to undergo a TKA who did not have patella resurfacing (usual care) were randomized with or without circumferential patella electrocautery. This was undertaken according to a randomly generated sequence of treatment allocation that was placed into numbered, sealed opaque envelopes. Participants were blinded to treatment allocation. There was no crossover. The primary outcome was Oxford Knee Score at 1 year postoperatively. Secondary outcomes were Bartlett Patella Score, Western Ontario and McMaster Universities Arthritis Index (WOMAC), and 12-Item Short Form Survey. Linear regression analyses were performed with adjustments by age, sex, and baseline (preoperative) scores. There were 142 participants recruited, of which 49 (35%) were allocated to the denervation intervention. Recruitment was stopped early when interim statistical analyses confirmed adequate numbers in both groups despite an imbalance in early treatment allocation rates due to the randomization method. The mean patient age was 71 years (range, 50 to 85) and 51% (n = 74) were women.

Results: No difference in Oxford Knee Score was detected at 1 year (mean difference [MD] 1.87; 95% confidence interval [CI] −1.28 to 5.03). No difference was detected in Bartlett Patella Score (MD 0.490; 95% CI −1.61 to 2.59) or 12-Item Short Form Survey (MD 0.196; 95% CI −2.54 to 2.93). A statistically significant difference in WOMAC was detected, but at a level less than the minimal clinically important difference for WOMAC (MD 4.79; 95% CI 1.05 to 8.52).

Conclusion: No clinically relevant benefit was detected from patella rim electrocautery in patients undergoing TKA who did not have patella resurfacing (including no benefit in terms of anterior knee pain). This treatment is therefore not recommended for clinical practice. Level of evidence: Level 1.