STT Joint Arthritis
Jacksonville, FL
Radial-sided wrist pain at the base of the thumb that doesn't come from the basilar joint — and doesn't respond to basilar joint injections — may be STT arthritis. Dr. R. David Graham at JOI evaluates STT arthritis as a distinct entity from CMC joint disease and treats it with targeted injection and, when surgery is needed, distal scaphoid excision with interpositional dermal allograft.
- STT = scaphotrapeziotrapezoidal joint — three bones at the base of the wrist/thumb
- Distinct from basilar joint (CMC) arthritis — different location, different surgery
- Conservative: injection + activity modification
- Surgical: distal scaphoid excision with interpositional dermal allograft
- Different from basilar joint surgery (no trapeziectomy for isolated STT disease)
- STT arthritis and CMC arthritis frequently coexist — both assessed at evaluation
The STT joint sits just proximal to the trapeziometacarpal (basilar) joint. When arthritis is localized to the STT level, the surgery is different — distal scaphoid excision with dermal allograft interposition rather than the full trapeziectomy + suspensionplasty performed for basilar joint disease.
Understanding STT Arthritis
The Other Arthritis
at the Base of the Thumb
The scaphotrapeziotrapezoidal (STT) joint is where the scaphoid articulates with the trapezoid and trapezium at the base of the wrist, just proximal to the basilar joint of the thumb. It is a distinct joint from the trapeziometacarpal (CMC) joint — the basilar joint — though the two are anatomically adjacent and frequently develop arthritis concurrently.
STT arthritis produces radial-sided wrist pain that is localized slightly more proximally and dorsally than basilar joint pain. The clinical distinction matters because the treatment is different. Basilar joint arthritis is treated with trapeziectomy plus suspensionplasty. Isolated STT arthritis — when the CMC joint is preserved — is treated with distal scaphoid excision and interpositional dermal allograft, which decompresses the STT joint without removing the trapezium.
In Dr. Graham's experience, STT arthritis and CMC arthritis frequently coexist. At evaluation, both joints are assessed clinically and radiographically. Fluoroscopic-guided injection into the STT joint can be both diagnostic (confirming the pain source) and therapeutic. When conservative management fails and surgery is needed, the operative plan is tailored to which joints are arthritic.
- ✓ STT arthritis: pain at base of wrist, proximal to thumb metacarpal base
- ✓ CMC (basilar joint) arthritis: pain at thumb metacarpal base, at the saddle joint
- ✓ Both produce radial-sided wrist/thumb pain — fluoroscopic injection confirms source
- ✓ Surgery for STT only: distal scaphoid excision + dermal allograft
- ✓ Surgery for CMC (basilar joint): trapeziectomy + suspensionplasty
- ✓ When both present together: combined procedure at same setting
Treatment
Conservative First — Targeted Surgery When Needed
Activity Modification & Splinting
Thumb spica brace or radial wrist brace for activity modification. Avoidance of pinch and grip activities that load the STT joint. NSAIDs for pain management.
Fluoroscopic-Guided STT Injection
Cortisone injection into the STT joint under fluoroscopic guidance — the joint is small and precise placement is required. The injection is both diagnostic (significant relief confirms STT as the pain source) and therapeutic. Repeated every 3–4 months as needed.
Surgical: Distal Scaphoid Excision + Dermal Allograft
When conservative management no longer provides adequate relief — distal scaphoid excision removes the arthritic portion of the scaphoid participating in the STT joint. A dermal allograft spacer is placed into the excision void, maintaining joint space and preventing impingement. The CMC joint is preserved if it is not arthritic.
Why Not Just Remove the Trapezium?
Trapeziectomy — removal of the trapezium — is the right surgery when the basilar (CMC) joint is arthritic. But for isolated STT arthritis with a preserved CMC joint, removing the trapezium is larger surgery than necessary. Distal scaphoid excision with dermal allograft interposition targets the arthritic joint specifically, preserves the trapezium, and produces reliable pain relief with a shorter recovery than a full trapeziectomy. When both joints are arthritic, both are addressed at the same procedure.
FAQs
Frequently Asked Questions
Related Conditions
Next Steps
Radial wrist pain that isn't
responding to basilar joint treatment?
STT arthritis is frequently overlooked when the CMC joint is assumed to be the culprit. A fluoroscopic-guided STT injection can confirm or exclude the diagnosis in a single visit.
Jacksonville Beach, FL 32250
No imaging required.