Primary endoprosthetic replacement of the arthritic CMC-1 joint

Objective Osteoarthritis of the carpometacarpal (CMC)-1 joint is a common condition that can cause significant pain and functional problems. When nonoperative management fails, surgery may be indicated. Resection of the trapezium, often combined with soft tissue stabilization, is still considered the gold standard. But recovery time is often prolonged and a significant number of patients remain unsatisfied in the long term. Knowing that total endoprosthetic joint replacement is one of the most successful achievements of orthopedic surgery, many attempts have been made to produce a replacement for the CMC‑1 joint that provides a better outcome than trapeziectomy. Indications Eaton–Glickel stage 2–3 CMC‑1 osteoarthritis. Contraindications Symptomatic pan-trapezial osteoarthritis (Eaton–Glickel stage 4), infection, young manual worker, poor bone quality or insufficient trapezium size. Surgical technique A dorsoradial approach to the CMC‑1 joint is used. Minimal resection of the trapezial and metacarpal articular surfaces, including osteophytes and loose bodies. Reaming of the trapezium and broaching of the metacarpal stem with dedicated instruments. Implantation of the endoprosthetic components. Selection of the correct neck length to ensure a stable joint. Closure of the capsule and skin. Postoperative management Immobilization of thumb for 2 weeks in a splint. Followed by a removable thumb CMC brace for 4 weeks, starting with gentle mobilization exercises. No forceful gripping or pinching the first 6 weeks. Results A specific design—the uncemented, ball in socket, metal on polyethylene total joint replacement—has stood the test of time and successful long-term clinical and radiographic outcome results have been published. Recent comparative trials have shown better pinch strength, better pain relief and faster functional recovery, when compared to trapeziectomy with ligament reconstruction and tendon interposition. The incidence of complications such as dislocation, polyethylene wear and cup loosening is acceptable.