The aim of this study was to make a mid-term evaluation of an unconstrained pyrocarbon prosthesis (Ascension®) in the treatment of idiopathic degenerative arthritis of the proximal interphalangeal joint of the hand.
13 implants (10 patients) were clinically and radiologically studied after a follow-up period of 71 months (range: 48-92 months).
The average ROM was 52° (± 27°STD). A luxation of the components did not occur and all implants are still in-situ. However, X-ray examination was unremarkable in only six fingers. In seven patients significant radiolucent lines (≥ 1 mm) were detected. Three prosthesis demonstrated axial subsidence and in one patient a loosening of the proximal component with axial rotation was observed.
The results of this study show a high complication rate after an average of 6 years after implantation. Radiolucent lines in half of the cases may be explained by a lack of osteointegration of the prosthesis. The average ROM differs significantly from patient to patient, which has to be taken into account when discussing different treatment options.