The thumb is the most extraordinary digit of the human hand, enabling both gripping and pinching. Because of its extensive use, it is subject to great tension forces and consequently to early osteoarthritis [1].

Trapeziometacarpal (TMC) osteoarthritis (OA) is the second most common degenerative joint disease, and the most frequent in the hand, with prevalence of 10% [2], [3], [4].

Diagnosis is based on clinical findings: pain, edema, instability, decreased range of motion, and deformity. On physical examination, a prominence in the dorsolateral region can be observed (due to subluxation and osteophytes), tenderness over the TMC joint, crepitus and compensatory metacarpophalangeal joint hyperextension [5], [6], [7].

Initial treatment should be conservative: activity modification, physiotherapy, thumb orthosis, anti-inflammatory drugs and corticosteroid injections. Although patients in the early stages of the disease typically respond favorably to conservative treatment, patients in more advanced stages or refractory cases often require surgical treatment [3]. Several surgical procedures have been described, but there is no clear gold-standard in the literature [8], [9].

Over the years, numerous implants tried to mimic the complex anatomy and function of the TMC joint. However, the vast majority showed high failure rates, secondary to infection, instability, dislocation, loosening and stiffness [1], [10], [11].

Interposition arthroplasty with PyroDisk (Integra LifeSciences) was first introduced in 2005 in the USA. Pyrocarbon has similar mechanical properties to cortical bone and has been extensively studied in the small joints of the hand and wrist. The PyroDisk implant is a biconvex disk with a central hole, enabling stabilization by autologous tendon graft through the trapezium, implant and first metacarpal bone. This tendon slip enhances implant alignment and stability in addition to the congruence between implant and concave bone surfaces (after preparation) (Fig. 1, Fig. 2).

This implant eliminates any problems of osteointegration, cement, polyethylene wear or metallosis [1]. However, the few studies evaluating it had short follow-up [1], [2], [3], [12], [13], [14], [15], [16], [17].

The objectives of the present study were to evaluate long-term clinical and radiological results of PyroDisk interposition arthroplasty, associated complications, rate of revision surgery and causes of revision.