Scaphotrapeziotrapezoidal (STT) joint arthritis is a condition that affects the tiny joint at the base of the wrist, just below the base of the thumb. While less common than other wrist conditions, it can significantly affect hand and wrist function, particularly gripping and pinching. This article explores the presentation, investigation and treatment options for STT joint arthritis. 

What is the STT joint of the wrist? 

The STT joint articulates the three bones on the outside of the wrist: the scaphoid, trapezoid, and trapezium. rthritis begins between the scaphoid and trapezoid and then moves to the scaphoid and trapezium. 

wrist anatomy showing the STT joint

Clinical Assessment of STT Joint Arthritis 

Patients with STT joint arthritis often report localised pain on the thumb side of the wrist. Activities that require pinching, gripping, or repetitive wrist motion exacerbate pain. Some individuals may also notice swelling, reduced range of motion, or a grinding sensation in the wrist.

Your doctor will examine your wrist for features of arthritis, including tenderness at the thumb side of the twist and grinding or popping sensation during wrist motion. Your doctor must examine other structures in your wrist to exclude other causes. Examples include the following:

Sometimes, wrist pain may have more than one cause. In one study, about 65% of X-rays with thumb arthritis also showed STT arthritis. 

Investigation of Scaphotrapeziotrapezoidal Joint Arthritis 

X-ray revealing STT joint arthritis

X-rays are the first-line imaging modality to confirm the diagnosis. They may reveal joint space narrowing, osteophytes, or subchondral sclerosis.

MRI provides a more detailed view of the soft tissues and can help rule out other conditions, such as ligament injuries or synovitis, that may mimic arthritis, such as De Quervain’s tenosynovitis or ganglion.

Ultrasound can also detect STT joint arthritis by visualising joint swelling, bone spur formation and increased synovitis. 

Treatment Options for STT Joint Arthritis 

The management of STT joint arthritis depends on the severity of the symptoms and the patient’s activity level. Treatment options range from conservative measures to surgical intervention.

Simple treatments include the following: 

  • Activity Modification. Reducing activities exacerbating symptoms, such as heavy lifting or repetitive wrist motion, can alleviate pain.
  • Bracing. Wrist splints or braces help immobilise the joint, reducing pain during activities.
  • Physiotherapy A tailored physiotherapy program focuses on range-of-motion exercises to maintain joint mobility and strengthening exercises for supporting muscles.
  • Medications Topical and oral Non-steroidal anti-inflammatory drugs (NSAIDs) can help reduce pain and inflammation.

Injections for STT Arthritis 

Injections can be a valuable adjunct to simple measures to reduce pain and improve function. Generally, we recommend injections with ultrasound guidance to improve the accuracy and effectiveness of injections. Injection options include the following: 

  • Corticosteroid Injections into the STT joint reduce inflammation and temporarily relieve pain. This option is suitable for moderate arthritis or individuals seeking to delay surgery.
  • Hyaluronic acid injections are less commonly used but may help lubricate the joint and reduce early arthritis symptoms. They also provide a longer-lasting effect than a cortisone injection without the harsh side effects. 

In cases with other joint involvement, such as the thumb CMC joint or radio-carpal joint, it might be helpful to inject both joints simultaneously. 

Surgical Options for severe STT joint Arthritis 

Surgery is considered when conservative treatments fail to provide relief and the condition significantly impacts daily life.

  • Resection Arthroplasty involves removing part of the trapezium to alleviate pain while preserving motion. It is often combined with tendon interposition or soft tissue reconstruction.
  • STT Joint Fusion (Arthrodesis) This procedure involves fusing the bones of the STT joint to eliminate pain. While it reduces joint mobility, it preserves overall wrist stability and strength.
  • Joint Replacement Although less common, advancements in joint replacement technology offer an option for patients seeking to maintain motion while reducing pain.

Final Word from Sportdoctorlondon about Scaphotrapeziotrapezoidal Joint Arthritis 

STT joint arthritis is a challenging condition that can significantly impact wrist function and quality of life. Early diagnosis through clinical assessment and imaging is key to effective management. Sometimes, this condition is confused with other pathologies, such as thumb arthritis or DeQuervain’s tenosynovitis. If you suspect STT joint arthritis, consult a sports medicine professional to explore the best treatment strategy. 

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Dr Masci is a specialist sports doctor in London. 

He specialises in muscle, tendon and joint injuries.