Signs of Trapezoid Bone Impingement
Clinical Presentation
The primary signs of trapezoid (and scaphotrapeziotrapezoid joint) impingement include localized radial-sided wrist pain, point tenderness over the STT joint region, weakness with grip, and pain exacerbated by wrist extension and radial deviation. 1, 2
Key Clinical Findings
Pain localization: Patients present with pain on the radial border of the wrist, specifically over the scaphotrapeziotrapezoid (STT) joint region 1, 2
Point tenderness: Nearly universal finding - present in all but 2 of 49 hands examined in one case series, located dorsally over the STT joint 1
Weakness and functional impairment: Significant loss of grasp and pinch strength occurs in approximately one-third of cases, with patients reporting difficulty performing routine daily tasks 1, 2
Loss of wrist motion: Reduced wrist range of motion, particularly extension, occurs in approximately one-third of affected hands 1
Provocative Maneuvers
Pain with grip: Weakness and pain are exacerbated during gripping activities 2
Wrist positioning: Pain worsens with wrist extension and radial deviation, as these positions increase loading across the STT joint 1
Functional limitations: Patients report difficulty with activities requiring forceful grip or wrist extension 2
Radiographic Signs
Supplementary radiographs with the wrist in maximal ulnar deviation are recommended when routine views appear normal but clinical suspicion remains high. 3
Imaging Findings
Joint space narrowing: Narrowing of the scaphotrapeziotrapezoid joint space is the hallmark radiographic finding 1
Subchondral changes: Subarticular cortical sclerosis and cyst formation are characteristic of degenerative changes 1
Scaphoid positioning: A dorsiflexed scaphoid position with scapholunate angle less than 45 degrees was noted in 38 of 45 hands (84%) 1
Advanced imaging: Tomography (historically) or CT can be useful for confirming suspected fractures or subtle degenerative changes when plain radiographs are inconclusive 4
Important Clinical Pitfalls
Normal routine radiographs: In cases of radial-sided wrist pain following trauma with normal standard radiographs, obtain supplementary views with maximal ulnar deviation to unmask STT pathology 3
Concomitant pathology: STT arthritis may occur in isolation or with concurrent thumb carpometacarpal joint osteoarthritis or scapholunate advanced collapse (SLAC) patterns, requiring comprehensive evaluation 5
Late collapse: Progressive intercarpal joint collapse with dorsiflexion instability of the lunate can develop in untreated cases 1