LONG-TERM FUNCTIONAL OUTCOME OF CARBON MATRIX SUPPORT PROSTHESIS IN CHONDRAL INJURY AND EARLY OSTEOARTHRITIS

Abstract

The clinical results of carbon matrix support prostheses for treatment of articular cartilage defects of the femoral condyle and patella were assessed in 97 patients (100 prostheses) between 1989–99. Patients were independently reviewed by subjective and objective criteria. Pre-operative and current visual analogue scores for pain (VAPS); Stanmore and modified Cincinnati functional rating scores were obtained. Forty-nine patients had lesions of the patella, forty-four patients of the medial femoral condyle and seven patients of the lateral femoral condyle.

Patella group – subjectively 49% reported they were improved, 8% unchanged and 43% worse. Stanmore score: 6 excellent and 17 good (47%), 5 fair and 21 were poor. The Cincinnati score increased from 26. 5 pre-operatively to 47. 5 currently (p< 0. 001). The mean VAPS decreased from 8. 1 to 5. 0 (p< 0. 001).

Medial femoral condyle group – subjectively 60% reported they were improved, 14% unchanged and 26% worse. Stanmore score: 8 excellent and 16 good (55%), 8 fair and 12 poor. The Cincinnati score increased from 22. 3 pre-operatively to 48. 5 currently (p< 0. 001). The mean VAPS decreased from 8. 6 to 5. 1 (p< 0. 001).

Lateral femoral condyle group – subjectively 42% reported they were improved, 29% unchanged and 29% worse.

Stanmore score: 2 excellent and 1 good (43%), 2 fair and 2 poor. The Cincinnati score increased from 35. 0 pre-operatively to 52. 0 currently (p< 0. 25). The mean VAPS decreased from 6. 5 to 4. 0 (p< 0. 25).

There were no statistical differences in outcome based upon gender, site, pre-operative functional rating score, diagnosis, or any correlation with age or length of follow up, or when comparing excellent/good with fair/ poor subgroups in patellae or femoral condyles in relation to these variables.

This study demonstrated that 49% improved in the patella group, 60% in the medial femoral condyle and 43% in the lateral femoral condyle groups. The use of these prostheses was effective on the medial femoral condyle for periods up to 10 years but the use in the patella and lateral femoral condyle was less successful.