Scapho-Trapezial-Trapezoid (STT) Tenderness

Historical Overview

• Scaphotrapeziotrapezoid (STT) tenderness is indicative of STT arthritis. It may also indicate injury to the scaphotrapezial-trapezoidal ligament structures.
• In 1978, Crosby et al¹ reported that the commonly observed pantrapezial arthrosis, although often focused at the trapezium-metacarpal joint, could also involve the STT joint.

Description

• Tenderness of the STT joint suggests that pain and weakness at the base of the thumb are due to STT arthritis.

Pathophysiology

• The STT joint is a common site for osteoarthritis.² It is possible that STT arthrosis is secondary to injury of the STT ligamentous structures.³

Instructions

1. Take patient history; there is an increased likelihood of STT arthritis with age >60 years
2. Palpate STT joint from volar, radial, and dorsal aspects

Diagnostic Performance Characteristics

• Point tenderness over the scaphotrapezial joint after applied pressure is the best and most precise clinical finding and can be elicited volarly, radially and dorsally.¹

• A positive result occurs when there is point tenderness and increased pain with pressure.

• A negative result occurs when pressure does not elicit tenderness.

• The progression of arthritic changes in the STT joint can be assessed with plain x-rays.²
• It may be impossible to tell on physical exam alone whether tenderness in the anatomic snuff box is secondary to a scaphoid fracture, scaphoid nonunion or STT arthritis. The distinction will usally equire an X-ray.

1. Crosby EB, Linscheid RL, Dobyns JH. Scaphotrapezial trapezoidal arthrosis. J Hand Surg Am 1978;3(3):223-234. PMID: 659818
2. Drewniany JJ, Palmer AK, Flatt AE. The scaphotrapezial ligament complex: An anatomic and biomechanical study. J Hand Surg Am 1985;10(4):492-498. PMID: 4020059
3. Scordino LE, Bernstein J, Nakashian M, et al. Radiographic prevalence of scaphotrapeziotrapezoid osteoarthrosis. J Hand Surg Am2014;39(9):1677-1682. PMID: 25037508