Abstract
Purpose of Study: To identify the functional outcome, quality of life and prosthesis survivorship in patients who have undergone the Avon patellofemoral arthroplasty at an independent centre.
Method and Results: Sixty-three patellofemoral arthroplasty (PFA) procedures were undertaken on 44 patients between May 1998 to May 2007. The primary and secondary outcome measures were knee function and quality of life, respectively. These outcomes were determined using the Oxford Knee Score (OKS) and EQ-5D and visual analogue score. Out of the forty-four patients 6 were deceased and 6 were lost to follow-up.
Therefore, thirty-two patients (50 PFAs) were included; nine males and 23 females.
Seventeen patients had bilateral PFA. The mean age of the patients was 65.8 years (SD 9.2). Follow-up averaged at 5.34years (range 2.1–10.2years) (SD2.64). The Oxford Knee Scores in this population showed a bimodal distribution. One group centred around 35 and the other around 60. The median Oxford knee score was 42.5 (IQR 34.25 to 54.25). Two sample t-test analysis of the population, divided as those above and below an OKS of 42, showed that follow-up time and age, did not differ between the groups (p=0.325, p=0.255 respectively). The quality of life outcome scores were significantly lower for bilateral compared to unilateral patients, with median scores of 50 and 72.5 respectively (p=0.03829). The cumulative survival at 5years for those with minimum 5 year follow-up (32 out of 50 PFA) was 100%. Three knees in total were revised. One patient developed bilateral tibiofemoral osteoarthritis, requiring revision to total knee replacement (TKA) at seven and 10 years. Another had persistent anterior knee pain and was converted to a TKA.
Conclusion: The Avon patellofemoral arthroplasty provides good functional outcome. The survivorship rate is promising although longer follow-up is required. Prudent patient selection is needed avoid high rates of revision to TKA.
Correspondence should be addressed to Diane Przepiorski at ISTA, PO Box 6564, Auburn, CA 95604, USA. Phone: +1 916-454-9884; Fax: +1 916-454-9882; E-mail: ista@pacbell.net
