A 53-year-old male military officer presented with complaints of chronic localised pain on the thumb basilar area of his dominant hand along with decreased grip strength. Medical history revealed a hand injury 2 years before in a motor vehicle accident that was treated with simple splinting. No fracture was reported.
The mechanism of his initial hand trauma was described as a high energy force applied axially on his outstretched palm (the patient was injured with his steering wheel during the collision). Mild swelling and tenderness on palpation over the thenar eminence was noticed on physical examination. Plain radiographs showed sclerosis of the scaphoid-trapezium-trapezoid articulating surfaces with associated joint space narrowing (Fig. 1). An ultrasound examination was performed subsequently that demonstrated irregularity of the scaphotrapezoidal articulation along with findings of accompanying synovitis (Fig.2). An MRI examination verified the aforementioned findings and relying on the clinical and imaging features, the clinicians suggested an MDCT examination in order to better delineate the joint pathology and the associated osseous surfaces (Fig. 3-4). The patient’s clinical history, together with the imaging findings established the diagnosis of a scaphotrapeziotrapezoidal (STT) posttraumatic osteoarthritis (Fig. 5) and the patient was referred to a specialised hand surgery clinic for possible surgical treatment.
The clinical evaluation and treatment of chronic wrist pain can often be a challenging diagnostic dilemma because the aetiology is broad and includes both intracarpal and intercarpal pathology [1-2]. With recent improvements in diagnosis and imaging of carpal disorders, the radiologists are able to confirm a clinical suspicion of injury and thus tailoring the appropriate therapy [1-3]. Scaphotrapeziotrapezoidal (STT) joint osteoarthritis has been estimated to account for 13% of all wrist arthritis cases and can cause significant pain and limitation of function [4-6]. Common predisposing factors are trauma, an abnormal trapezio-trapezoidal inclination and laxity of the capitotrapezial ligament [4-6]. Although the underlying pathophysiologic mechanisms that may lead to posttraumatic osteoarthritis are not well understood and clarified, studies have shown that the degree and severity of articular cartilage damage and the joint surface incongruity both correlate with the development of osteoarthritis [7]. STT arthritis is usually manifested with pain, swelling and stiffness over the thumb base and physical examination might reveal local tenderness and a radial grind in chronic cases [4-6]. However the clinical signs and symptoms are not considered pathognomonic and differential diagnosis from other causes such as scaphoid disorders, trapezio-metacapal osteoarthritis, DeQuervain tenosynovitis, symptomatic ganglion cysts may be required [4-6]. Therefore the radiologic evaluation is of paramount importance in treatment planning. Plain radiographs may be normal early in the setting of STT arthritis, while in advanced stages show the characteristic osteoarthritic features. High resolution ultrasonography of the small joints may provide additional information by revealing the accompanying synovial reaction and inflammation [8]. MRI has become an important diagnostic tool for evaluation of chronic hand and wrist pain because it can identify both intracarpal and intercarpal abnormalities [1-3]. In our case MRI verified the radiographic and ultrasonographic findings and also showed bone marrow oedema in the articulating bones of the STT joint. Furthermore an osteochondral defect was identified in the capitate bone, which was attributed either due to STT osteoarthritis and altered local biomechanics or as a result of the remote trauma. MDCT with its superior spatial resolution together with the availability of multiplanar reformations can delineate the osteoarthritic changes equally or even better than plain MRI [9]. STT arthritis is initially treated conservatively with splinting, oral analgesics or local corticosteroid injections. In advanced cases surgical treatment consists primarily of fusion of the STT joint, but alternative operative techniques include trapeziectomy, excisional arthroplasty, and prosthetic replacements [4-6, 10].
Scaphotrapeziotrapezoidal (STT) osteoarthritis
Based on the provided X-ray, ultrasound, MRI, and MDCT images, the main imaging features include:
Taking into consideration the patient’s history (wrist trauma two years ago, chronic radial wrist pain, and decreased grip strength) and the above imaging findings, the following should be considered as possible diagnoses or differential diagnoses:
Considering the patient’s age, symptoms (radial wrist pain, decreased grip strength), history of trauma (treated after a car accident), and imaging findings (significant degenerative changes at the STT joint surfaces, bone marrow edema, osteochondral involvement), the most likely diagnosis is:
Scaphotrapeziotrapezoid (STT) Joint Osteoarthritis (Post-traumatic Degenerative Changes).
If needed, further evaluation with arthroscopy or follow-up imaging during clinical treatment could help clarify the extent of cartilage damage and joint stability.
Special Note: If the patient has osteoporosis or other joint disorders, exercises should be guided by a physician and rehabilitation therapist to progress gradually, with caution to prevent falls or further injury.
This report is a reference medical analysis based on available data and cannot replace professional, in-person medical diagnosis and treatment. If you have any questions or changes in your condition, please seek medical attention or consult a specialist promptly.
Scaphotrapeziotrapezoidal (STT) osteoarthritis
