Base of thumb arthritis for GPs: CMC spectrum, trapeziectomy, and dual-mobility thumb arthroplasty
Hand and wrist surgeon Dr Ken Klump reviews why base-of-thumb arthritis matters, what splints and injections can (and cannot) do, why trapeziectomy was the old gold standard, and how dual-mobility CMC arthroplasty is changing recovery and strength for selected patients.
- Dr Ken Klump — hand and wrist surgeon / microsurgeon
- Orthopaedic surgeon trained in Queensland with two fellowships in hand and microsurgery. Works with Dave Graham and Dan Williams at the Madraba Hand Clinic (on-site hand therapy). Host thanked him as “Dr. Klump”; first name used as Dr Ken during the introduction.
- Host — Narelle
- Organised the session at Gold Coast Private; opened and closed with thanks and Q&A.
This is a GP-facing summary of one Gold Coast CPD seminar on Saturday 6 June 2026 (Otter title: “Hand Surgery Presentation”; otter id AydX6cnjC3tbOYvnVFdNEVCBHLg). About 21 minutes (~1259 s). It is not personal medical advice and not a substitute for specialist assessment, imaging, or the patient in front of you. Otter.ai garbles some names and terms (Madraba for the clinic spelling as heard; scaphotrapezial / STT joint; De Quervain’s). Where the recording is unclear, this write-up cleans the clinical term rather than inventing a surname, implant brand claim, or outcome not in the talk. Speaker disclosures in the talk included industry-linked fellowship funding (Artis / Acumen mentioned).
Clinic context and referral pathway
Dr Klump described a team model at the Madraba Hand Clinic with Dave Graham and Dan Williams and on-site hand therapists. Across the three surgeons there is a spectrum of skills (including plastic-trained hand surgery and paediatric/microsurgery interest). GPs can refer when unsure whether the patient needs a surgeon, hand therapy, or both — the clinic triages and can offer one or both in the same pathway.
They also run a text-number referral service (mainly for emergency departments, but usable when someone turns up after skateboard or ski injuries and needs faster access). Referral pads were left for the audience. The point for coast GPs: some hand injuries can come straight for washout or review rather than bouncing through overloaded public pathways.
Why base of thumb (CMC) arthritis matters
Base of thumb arthritis is common on X-ray, and about 15% of the population is symptomatic. It is the second most common arthritis in the hand after DIP joint disease, but often more debilitating: what makes the hand functional is an opposable thumb. A sore finger can often be bypassed; a painful thumb tends to present earlier and more disruptively.
Long-lasting pain or functional limitation at the base of the thumb is worth a structured conversation about options earlier than the old “wait until sixties” reflex — because newer reconstructive choices change the risk–benefit for still-functional patients.
Radiographic spectrum and early care
There is a radiographic classification. Early on the joint can widen before classic arthritis shows; then arthritis in the CMC joint; then subluxation; grade four involves the top and bottom of the trapezium with scaphotrapezial (STT) joint involvement. Stage changes management.
Early column on the talk’s slide: start with an injection, try splints, then consider certain operations. Splints work well for pain when the hand is quiet — elderly patients who mainly want comfort. They work poorly when the person has a functional job: the splint comes off and the pain returns.
Pyrocarbon disc and trapeziectomy
Pyrocarbon interposition (earlier disease)
In earlier stages, surgeons used a pyrocarbon disc as an interposition arthroplasty: partially resect the sore surfaces, put something between them so they cannot grind. It can go well, but the disc can spit out and does not always contour perfectly — “like trying to put a coin in the middle of a joint.”
Trapeziectomy — long-standing gold standard
For a long time the gold standard has been trapeziectomy: remove the trapezium and suspend the thumb in one of many ways. Many techniques usually means no perfect answer. Goals: remove painful surfaces, allow some abduction (even if adduction creep remains), and create scar for tension/balance.
- Reliable and reproducible; roughly 90% of patients happy because pain and whole-hand dysfunction improve
- Slow recovery — long time in cast/splint; often months before people feel settled (speaker: ~3 months in splint/cast thinking, up to ~12 months to really be happy)
- Thumb shortens; grip and strength are not fully restored; dexterity measures may not jump as much as patients hope
- Historically pushed toward people in their 60s–70s winding down physically — not ideal for still-heavy functional work
- Failed trapeziectomy is hard to salvage if the thumb has sunk and pain continues
Fusion still has a role in a younger labourer who needs raw strength — not featured as the main slide path, but mentioned as the usual strength-preserving alternative in that niche.
Dual-mobility thumb CMC arthroplasty
Described as putting a hip upside down. Several implants on the market; fourth-generation dual-mobility constructs: a metal head, a plastic head/liner over that, sitting in a metal cup — more motion with lower dislocation risk. In the model discussed, both cup and stem are cementless. Link length is preserved, which changes function. Current form since about 2018; Europe much longer; Australia about five years. Large European experience cited (France/Switzerland; speaker mentioned >150,000 in that region over the implant era).
Technically the cup is the fiddly part (trapezium looks different every 15° on X-ray). Capsule repair is a surgeon preference — some French centres leave capsule open and close skin only; the speaker repairs for stability. Soft-tissue complications (trigger thumb, De Quervain’s) occur; he often releases De Quervain’s at arthroplasty. Trapezium fracture risk was framed as lower than those soft-tissue rates. Dislocation/revision rates were described as approaching large-bearing arthroplasty standards (~1–2% revision thinking).
2023 RCT vs trapeziectomy
A 2023 randomised controlled trial compared trapeziectomy with the modern dual-mobility implant in matched groups. Both improve pain and hand scores (e.g. DASH / daily living). Arthroplasty patients were happier faster; both groups converged somewhat later. Range of motion favoured arthroplasty. Grip, key pinch, and tip pinch favoured arthroplasty — closer to pre-arthritis function.
Patients often talk about pain, not pinch metrics. Explaining arthroplasty risks versus a chance to regain key/tip pinch and grip is a harder but important discussion — especially for musicians, manual workers, and people who need thumb reach/strength.
Cost, registry, and recovery
| Topic | From the talk |
|---|---|
| Registry | Not fully on the entire registry yet (at time of talk) |
| Out-of-pocket | Roughly $3.5k–$4.5k depending on implant/competition |
| Funding help | Clinic relationships with insurers and hospitals; may shift venue to improve cover |
| Recovery | ~4 weeks in a splint, then out toward usual activities (vs months for classic trapeziectomy pathways) |
| If it fails | Can still do trapeziectomy — useful for younger functional patients |
When to refer
- Age or disease severity
- Failed splinting
- Weakness or wasting
- Cannot do the job / cannot do the things they want
Related companion reading for coast GPs: orthopaedic urgent care and shoulder surgery briefings on the same education day series.
Lego Endurance patient story
The speaker showed a ~3000-piece Lego Endurance (Ernest Shackleton’s Antarctic ship). A patient in his late 50s — retired, travelling, saxophone/guitar/piano — had left the set unfinished for three and a half years because of base-of-thumb arthritis. After dual-mobility arthroplasty he holidayed at week two, returned at week four, and completed the model between weeks four and six, bringing the photo to review. Preserving thumb length and strength mattered for keyboard reach and instrument grip. Hand therapists in the room agreed the recovery pattern is changing.
Q&A: MCP vs CMC, female predominance
MCP osteoarthritis is less common than CMC OA. MCP disease is more often post-traumatic or rheumatoid. Osteoarthritis and psoriatic arthritis tend toward DIP joints; pure OA tends toward the CMC. The speaker had recently fused an MCP for rheumatoid disease with poor joint surfaces.
Why more common in women at the CMC? It is a highly mobile saddle joint; women have more ligamentous laxity — a plausible contributor. He also noted that early arthritis can be very painful, then less so as motion is lost — so presentation patterns may differ by sex and activity.
Take-home messages
- ~15% symptomatic base-of-thumb arthritis; functionally important because of the opposable thumb
- Splints/injections first when the hand is quiet; functional workers often abandon splints
- Trapeziectomy remains reliable for pain but slow, weakening, and hard to revise if it fails badly
- Dual-mobility CMC arthroplasty: cementless, ~4-week splint, better grip/pinch in 2023 RCT data; out-of-pocket/registry caveats; clinic can help with insurers
- If arthroplasty fails, trapeziectomy is still available — opens the door for younger functional patients
- Refer for failed conservative care, weakness/wasting, or life/job limitation
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