We conducted a prospective, randomised and double blinded study to observe the recovery of knee function in 50 patients undergoing knee replacement with or without patella resurfacing.

Patients were assessed pre-operatively, at four months and a minimum 18 months after surgery using three scoring systems, the Knee Society Clinical Outcome Score, WOMAC and the SF-36 health questionnaire. In addition the active range of knee movement when weight bearing was measured using an electrogoniometer. Patients were asked to undertake 11 standardised activities including level walking, stair climbing and getting into and out of low chairs. Patients were randomised at the time of surgery into receiving a knee replacement with or without patella resurfacing.

Forty-two patients, (18 with patella resurfacing, 24 with no resurfacing) completed assessments at all time intervals. All patients in the study demonstrated an improvement in terms of pain relief and function by four months after knee replacement with a further but less significant improvement by 18 months. The active range of knee movement measured by electrogoniometry recovered to the pre-operative range for all activities but there was no increase in knee movement. Patients who had patella resurfacing had a significantly lower (p < 0.02) score on the Knee Society Clinical Outcome function score at 18 months compared to patients without patella resurfacing. There was no significant difference (p > 0.05) in the active range of knee movement with or without patella resurfacing, although patients with patella resurfacing in general had slightly poorer range of movement particularly for activities that required knee flexion beyond 70 degrees.

We concluded that in this study knee function was not improved by patella resurfacing when compared to a matched group of patients without resurfacing. As patients recovery stabilises by 18 months it appears that the final functional outcome following knee replacement is not enhanced by patella resurfacing.