Proximal interphalangeal joint replacement with pyrolytic carbon prostheses.

Objective: Prosthetic joint replacement to reduce pain and maintain function of the proximal interphalangeal joint.

Indications: Symptomatic arthritis of the proximal interphalangeal joint with preservation of the collateral ligaments, sufficient bone support, and intact or at least reconstructable extensor tendons.

Contraindications: Lack of stability, e. g., as a result of rheumatoid arthritis or destruction of the ligaments caused by an accident. Nonreconstructable extensor tendons. Florid or chronic infection. Lack of patient compliance.

Surgical Technique: Dorsal approach to the proximal interphalangeal joint. A triangular tendinous flap with pedicle, based distally on the insertion of the medial band, is lifted up, leaving the lateral bands intact. The joint surfaces are resected while maintaining the palmar plate and the collateral ligaments. The trial prosthesis is fitted, its position is checked, and the final unconstrained prosthetic components are inserted using a press-fit technique. The dorsal aponeurosis is reapproximated.

Results: 20 patients were treated for posttraumatic or idiopathic arthritis with 24 pyrolytic carbon PIP prostheses, and a follow-up examination was carried out after an average of 15 months (6-30 months). Surgical management was changed from arthroplasty to arthrodesis in three cases. For the remaining prostheses, an average range of motion of 50 degrees was achieved for the proximal interphalangeal joint. On the visual analog scale (VAS; 0: no pain, 10: incapacitating pain), the patients suffered few symptoms (VAS: 0-3). 80% of patients said they were satisfied with the outcome of the operation. In three cases (one infection, two dislocations) the prostheses had to be removed and arthrodesis performed. Migration of the distal components was observed on the radiographs in five cases, and of the proximal components in four cases, although this did not have any effect on the functional parameters. The development of a painless noise ("squeaking") was noticed in nine out of 21 prostheses. However, as with prosthetic migration, this did not cause any functional deficits.