Revision patellofemoral arthroplasty: three- to seven-year follow-up.

In this series, a failed first-generation patellofemoral arthroplasty was revised to a second-generation prosthesis. Fourteen knees were prospectively followed up for a mean of 60 months. Primary procedure failure was due to component malposition, subluxation, polyethylene wear, or overstuffing. Mean Bristol knee scores improved from 58 (range, 36-86) to 79 (range, 38-100) (P < .001). Mild femorotibial arthritis (Ahlbach stage I) was present in 5 knees and predicted a poorer outcome. At most recent follow-up, there was no evidence of wear, loosening, or subluxation. Significant improvement can be obtained when revising the failed patellofemoral arthroplasty, provided there is no femorotibial arthritis.

Development and early results of a new patellofemoral arthroplasty.

UNLABELLED: A new patellofemoral arthroplasty is described, based on a previous design of total knee arthroplasty. The indications are for patients with specific isolated patellofemoral disease with advanced chondral or arthritic damage. The design and technique of insertion is detailed. Three hundred six patellofemoral arthroplasties have been done in 240 patients. The initial results show a high level of pain relief and improvement in function. Two-year followup is available for treatment of 124 knees and 5-year followup is available for treatment of 33 knees. There has been no deterioration in pain or function with followup to 5 years, and there were no late complications attributable to the arthroplasty. Disease progression in the tibiofemoral joint has occurred in 14 patients (16 knees, 5%) requiring revision in 10 of these patients (11 knees, 3.6%). Persistent anterior knee pain was recorded in 14 knees (4%). The short-term results using this new design were better than those of the prosthesis that we used previously, especially concerning malalignment and wear. It offers a reasonable alternative to total knee replacement in the small group of patients with isolated patellofemoral disease. LEVEL OF EVIDENCE: Therapeutic study, Level II (prospective cohort study). See the Guidelines for Authors for a complete description of levels of evidence.

When should we do knee replacements?

It is not known whether it is better to perform total knee replacements early or late in the course of arthritis. To examine the determinants of patient-related outcomes after knee replacement, we examined 812 patients in the Avon knee registry, in whom pre-operative and 5-year post-operative American Knee Society Scores were available. Ninety percent had a good outcome at 5 years. Women had significantly more severe disease at the time of surgery than men. Older people (>79 years) had the worst disease at the time of surgery, and made the least health gain, although their overall outcomes were still good. Those with the most severe disease at the time of operation made greater gains to those with less disease, but remained in worse health at 5 years, suggesting that earlier surgery may be preferable.