Patellofemoral joint replacement - Mean five year follow-up.

Background: The Femoro Patella Vialli FPV is a second-generation patellofemoral arthroplasty implant. It is the second most commonly used patellofemoral implant in the National Joint Registry of England and Wales. This is the first published mid-term outcome series for this prosthesis.

Methods: We reviewed the outcomes for all patients who had patellofemoral arthroplasty. Primary outcome was the intention to revise the implant; secondary outcome measures were Oxford and Kujala outcome scores.

Results: A total of 43 FPV patellofemoral joint prostheses were implanted in 32 patients at our institution between April 2004 and December 2012. Mean follow-up was 65 (30-119) months. Only one patient was lost to follow-up. At final follow-up the mean flexion was 110° (85°-130°). Five of 43 knees required revision to a total knee replacement because of progressive tibiofemoral osteoarthritis. Revisionswere carried out after amean of 56 months (30-109). There was no radiographic loosening in any case. The most recent functional assessment showed that the mean Oxford Knee score (OKS) has improved from 18 (five to 35) preoperatively to 29 (nine to 45) and the Kujala score from 35 (five to 74) preoperatively to 58 (18-91).

Conclusions: Midterm results with FPV prosthesis demonstrate that moderate outcomes can be achieved. Patellofemoral arthroplasty may be used to delay total knee replacement but judicious patient selection to identify truly isolated patellofemoral osteoarthritis is necessary. Chondral lesion in weight bearing area can lead to early implant failure. The main cause of failure was progressive tibiofemoral osteoarthritis.