A modular prosthesis for patellofemoral arthroplasty: design and initial results.

UNLABELLED: This study was designed to determine if a new and modular prosthesis for patellofemoral arthroplasty would produce results at least as good as those reported for other designs, while simultaneously eliminating the risks of patellar revision should total knee arthroplasty be needed in the future. Another issue was its suitability for the older patient with isolated patellofemoral arthritis in order to avoid destruction of the normal femoro-tibial compartments involved in total knee arthroplasty. Finally, I sought information about the safety and longevity of this prosthesis when used for patellofemoral arthroplasty in severely disabled patients too young to be considered for total knee replacement. From a cohort of 16 patients (8 studied retrospectively and 8 prospectively), aged 26 to 81 years, and followed up for 2.75-6.25 years, 15 (94%) rated their results excellent or good using the Activities of Daily Living Scale. These results are better than previously reported for other prosthetic designs. To date, no patient in this study group has required conversion to a total knee arthroplasty. The design has proven safe for use in both the older and younger patient, but longer followup will be needed to assess greater longevity. LEVEL OF EVIDENCE: Therapeutic Study, Level IV-8 (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.