Metacarpophalangeal hyperextension in trapeziometacarpal osteoarthritis: Relationship to first metacarpal head shape, and clinical impact

• Published in: Hand surgery and rehabilitation 2024-09, Vol.43 (4), p.101725, Article 101725
• Main Authors: Degeorge, Benjamin, Delvaque, Jean-Gabriel, Carre, Remi, Teissier, Jacques, Chammas, Michel
• Format: Article
• Language: English
• Subjects: Aged; Carpometacarpal Joints - diagnostic imaging; Carpometacarpal Joints - physiopathology; Female; Hand Strength - physiology; Humans; Hyperextension; Male; MCP; Metacarpal Bones - diagnostic imaging; Metacarpal Bones - physiopathology; Metacarpophalangeal; Metacarpophalangeal Joint - diagnostic imaging; Metacarpophalangeal Joint - physiopathology; Middle Aged; Morphology; Osteoarthritis; Osteoarthritis - diagnostic imaging; Osteoarthritis - physiopathology; Pain Measurement; Pinch Strength - physiology; Radiography; Range of Motion, Articular; Retrospective Studies; Thumb - diagnostic imaging; Thumb - physiopathology; Trapeziometacarpal; Trapezium Bone - diagnostic imaging; Trapezium Bone - physiopathology
• ISSN: 2468-1229; 2468-1210; 2468-1210
• DOI: 10.1016/j.hansur.2024.101725

The aim of this study was to determine whether the shape of the first metacarpal head influences metacarpophalangeal hyperextension, and to evaluate the influence of metacarpophalangeal hyperextension on hand pain and function in patients with trapeziometacarpal osteoarthritis. 362 patients with painful basal thumb osteoarthritis were evaluated over a 2-year period. Pain rating on a visual analog scale, trapeziometacarpal and metacarpophalangeal motion, and grip and pinch strength were evaluated. The shape of the metacarpal head was assessed on strict lateral radiographs using the “A/r” ratio. Round metacarpal heads had significantly greater and more frequent metacarpophalangeal hyperextension than flat heads (28° vs. 8°, and 78% vs. 29%). Metacarpophalangeal hyperextension adversely impacted trapeziometacarpal motion in antepulsion (27° vs. 32°), abduction (25° vs. 30°) and pinch strength (3.6 vs. 4.6 KgF). Our findings indicate that the shape of the metacarpal head influences metacarpophalangeal hyperextension in trapeziometacarpal osteoarthritis. Metacarpophalangeal hyperextension adversely impacted pinch strength and trapeziometacarpal motion. Level IV, Retrospective case series.