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.