Anterior knee pain post Total knee Replacement (TKR) has been reported to be as high as 49%. The source is poorly understood; both the peripatellar soft tissues and the infrapatellar fat pad have been implicated. Immunohistochemical studies demonstrate hyperinnervation of the peripatellar soft tissues.

In theory circumferential electrocautery denervates the patella. However there is little evidence that this practice translates into improved clinical outcomes

This study aimed to find the effect on clinical outcome, of intraoperative circumpatellar electrocautery in patients undergoing TKR.

200 patients undergoing primary TKR were randomised to circumferential circumpatellar electrocautery or nothing. Patients were assessed for Visual (VAS) for anterior knee pain and Oxford Knee Score (OKS) preoperatively, 3 months, 6 months and 1 year post-procedure. Patients and assessors were blinded to treatment allocation until the end of the study.

There were 91 patients in the electrocautery group and 94 controls. The mean VAS improvement from pre-op to one year was 3.8 in both groups. The mean improvement in OKS was 16.6 points in the control and 17.7 in the electrocautery group (p= 0.40). There were no significant differences between the two groups in terms of VAS or OKS at any other time.

Although previous studies have conflicting outcomes, to our knowledge this is the first prospective randomised controlled blinded trial of significant power, to evaluate the effect of peripatellar diathermy in TKR. We conclude that denervation electrocautery of the patella makes no difference to the clinical outcomes of TKR.