Overview
- Very common, most often in postmenopausal women
- Basal thumb pain with pinch and grip, positive grind test
- Late metacarpal adduction with compensatory MCP hyperextension
- Splint, hand therapy and corticosteroid injection first
- Trapeziectomy, with or without LRTI, is the commonest operation
- Arthrodesis or replacement in selected patients
Western Health Orthopaedic Registrar Presentation – CMC Osteoarthritis by Dr Todd Mason
Anatomy
- Dorsoradial ligament is the primary restraint to dorsal subluxation
- Anterior oblique (beak) ligament attenuation accompanies subluxation and degeneration
- Commonest site of hand osteoarthritis surgery, mostly in postmenopausal women
Classification
Eaton-Littler
| Stage | Radiographic features |
|---|---|
| I | Normal or widened joint |
| II | Osteophytes under 2 mm |
| III | Osteophytes 2 mm or more and sclerosis |
| IV | Scaphotrapeziotrapezoid (STT) involvement |
Original publication Eaton RG, Littler JW. Ligament reconstruction for the painful thumb carpometacarpal joint. J Bone Joint Surg Am. 1973;55(8):1655-66.
- Stage correlates poorly with symptoms
Clinical Features
- Shoulder sign from dorsoradial subluxation
- Zigzag deformity with MCP hyperextension
- Positive grind and lever tests
- Carpal tunnel syndrome commonly coexists
Investigations
- Roberts true AP view and stress views
- Check the STT joint, as involvement alters surgical choice
Management
- Thumb spica splint at night and during heavy use
- Corticosteroid injection is more durable in early disease
- Trapeziectomy for advanced disease
- LRTI adds little to simple trapeziectomy, which has fewer complications
- First metacarpal extension osteotomy for early disease in younger patients
- Arthrodesis for young heavy manual workers
- Dual mobility arthroplasty gives faster recovery and pinch, with dislocation and loosening concerns
Complications
- Superficial radial nerve neuroma
- Complex regional pain syndrome
- Metacarpal migration onto the scaphoid after trapeziectomy
- Correct MCP hyperextension over about 30 degrees
Prognosis
- Pinch strength takes up to a year to recover
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.