Total joint replacement at the thumb base — an alternative to trapeziectomy for selected patients with thumb arthritis, using a prosthesis to restore pain-free movement.
Thumb carpometacarpal (CMC) joint replacement is a surgical option for patients with thumb base arthritis (CMC arthritis) who have not responded to conservative treatment. The procedure involves replacing the damaged joint surfaces with a prosthetic implant, aiming to relieve pain and restore the natural saddle-joint movement of the thumb.
The CMC joint is a saddle-shaped joint at the base of the thumb where it meets the trapezium bone of the wrist. Arthritis here is common, particularly in women over 50, and causes pain with gripping, pinching, and fine motor tasks. While trapeziectomy (removal of the trapezium) remains the gold standard for most patients, thumb joint replacement is an option for selected individuals who wish to preserve bone or have specific anatomical or lifestyle considerations. Dr Ma discusses all options at consultation to help you make an informed decision.
Symptoms
Pain at the base of the thumb — aggravated by pinching, gripping, or opening jars
Swelling and tenderness over the CMC joint
Weakness of pinch and grip
Grinding or crepitus with thumb movement
Stiffness in cold weather or after periods of rest
Loss of thumb mobility and web space narrowing in advanced disease
Diagnosis
How it is diagnosed
Clinical examination — grind test, pinch strength, range of motion assessment
X-ray of the thumb (PA, lateral, and stress views) to grade arthritis
CT scan in selected cases to assess joint anatomy for implant sizing
Discussion of implant versus resection options based on age, demand, and imaging
Treatment
When to consider surgery
Thumb CMC joint replacement uses a two-component prosthesis — a metacarpal stem and a trapezial cup — to recreate the saddle joint. The Touch CMC prosthesis is one such system used in selected patients. Joint replacement preserves the trapezium bone, maintaining normal bony anatomy and providing a reconstructed joint that moves naturally. CMC replacement is an excellent option for patients with moderate to severe arthritis who have not responded to non-surgical treatment. Dr Ma will assess your individual circumstances — including your anatomy, preferences, and goals — to advise on the most appropriate procedure for you.
CMC arthroplastyTouch prosthesisDay surgeryBone-preserving optionRegional or general anaesthetic
Typical recovery Thumb splinting for 4–6 weeks after surgery. Hand therapy for 8–12 weeks to restore movement and pinch strength. Return to light activities at 6–8 weeks. Full function for most daily tasks at 3–6 months. Heavy pinch activities may take longer and vary by individual.
Seek specialist assessment if: Thumb base pain that persists despite hand therapy, splinting, and cortisone injections — or significant weakness affecting daily activities — warrants a specialist review to discuss all surgical and non-surgical options.
Dr Ma consults at Chatswood (Healthpac Medical Centre, Level 1/7 Help St) and Strathfield (Strathfield Private Hospital). Call (02) 8112 8569 or book online.
Frequently asked questions
Thumb CMC joint replacement is a well-considered option for patients with moderate to severe thumb base arthritis who have not responded to conservative measures. Whether joint replacement or trapeziectomy is the right choice depends on a number of individual factors — including anatomy, lifestyle, and personal preferences. Dr David Ma will carefully discuss both options with you at consultation to determine which procedure best suits your situation.
Both trapeziectomy and CMC joint replacement are effective procedures for thumb base arthritis. Trapeziectomy is the most established operation with an excellent, well-documented track record. CMC joint replacement offers a bone-preserving alternative with a natural reconstructed joint surface, allowing a good range of motion and pain relief. Dr Ma discusses both approaches based on your specific anatomy, X-ray findings, and what matters most to you, to help you make a fully informed decision.
The Touch CMC prosthesis is a total joint replacement implant designed specifically for the thumb base (carpometacarpal) joint. It consists of a metacarpal stem and a trapezial cup, restoring the saddle-joint anatomy. It aims to relieve pain and preserve a more natural arc of thumb movement compared to resection procedures.
The thumb is protected in a splint for 4–6 weeks after surgery. Hand therapy begins to restore movement and strength over 8–12 weeks. Most patients return to light activities within 6–8 weeks. Heavy pinch and grip activities take longer — typically 3–6 months. Recovery varies between individuals.
A GP referral is recommended for Medicare rebates but not required to book.
