FEMORO-PATELLAR PROSTHESIS FOR ISOLATED PATELLO-FEMORAL ARTHRITIS: STUDY OF 60 CONSECUTIVE CASES WITH 10 YEARS FOLLOW-UP

Abstract

Background: Femoro-patellar arthritis (FPA) is less frequent than femoro-tibial arthritis, but still a challenging problem for orthopaedic surgeons. Several treatment have been described from lateral retinaculum release to TKR, with special features to patellar prosthesis. The purpose of this study was to evaluate a large consecutive series of femoro-patellar prosthesis (FPP), to learn about the late outcome, complications and performance.

Material and Methods: Between 1992 and 2004, 60 prosthesis were performed by one of the authors in 55 patients with a mean age of 59 years; 44 were femal and 13 male, 5 had bilateral prosthesis. 62% had essential arthritis with trochlear dysplasia. 78% were graded Iwano III or IV.

Resurfacing cemented Themis^® prosthesis was used in all cases, with a lateral approach associated with a tibial tubercle osteotomy to achieve correct aligment of extensor mechanism. None patient was lost to follow-up.

Results: Mean follow-up was 10 years (46–218 months). During the study, 12 prosthesis were converted to TKR because of femoro-tibial arthritis; but the mean delay between FPP and TKR was 12 years. At revision, 48 FPP were evaluated by an independent examinator. IKS score raised from 106 to 157, knee score from 57 to 89 and function score from 49 to 78. Pain, ability to walk and to climb stairs were improved. Radiography did not demonstrate radio-lucent lines, wear or loosening. 95% had correct aligment of patellar button, without tilting. Survival rates of FPP were 89% at 10 years and 82% at 15 years.

Conclusion: Resurfacing FPP is a reliable procedure offering good clinical performance and outcomes. The authors recommend the use of FPP for isolated FPA, without knee diformity, in association with tibial tubercle osteotomy.