Proprioceptive role of the abductor pollicis longus in thumb carpometacarpal osteoarthritis: An anatomical and immunohistochemical study
Authors' conclusion
Greater APL slip number was associated with increased cartilage cellularity, consistent with a more cellular cartilage phenotype in specimens with higher APL anatomical complexity. The inverse relationship between S-100 status and MC1 OA severity supports a potential role of innervation-related factors in structural degeneration.
Study context
- Population
- Fresh-frozen cadaver hands (mean age 68 years, range 53–95), dissected June 2022–December 2023
- Participants
- 20 cadaver hands
- Outcome
- Association of APL tendon variability and proprioceptive innervation of its insertions with structural degeneration in thumb CMC OA (cartilage degeneration, osteophyte area)
Methodological detailsanatomical and immunohistochemical study, cadaveric, Hematoxylin-eosin and alcian blue staining; PGP 9.5 and S-100 immunostaining; International Cartilage Research Society (ICRS) grading; Mankin and Otte scores
- Anatomical and immunohistochemical study
- Cadaveric
- Hematoxylin-eosin and alcian blue staining; PGP 9.5 and S-100 immunostaining; ICRS grading; Mankin and Otte scores
Main finding
As reported in the abstract
APL tendon morphology, innervation and structural degeneration
- Accessory abductor pollicis longus (APL) tendinous slips present
- 18/20 (90%)
- APL slips per specimen
- 3-6
- Correlation of APL slip number with osteoarthritis (OA) severity at trapezium (r)
- −0.24 [−0.61, 0.22]
- Correlation of APL slip number with OA severity at MC1 (r)
- 0.14 [−0.31, 0.55]
- Correlation of APL slip number with cartilage cellularity (r)
- 0.47 [0.04, 0.76]
- Correlation of APL slip number with Mankin score (r)
- 0.27 [−0.20, 0.63]
- Correlation of APL slip number with Otte score (r)
- 0.36 [−0.10, 0.69]
- Association of S-100 status with OA severity at MC1 (r)
- −0.52 [−0.78, −0.10]
Observational data: associations, not effects.
Original publication
Proprioceptive role of the abductor pollicis longus in thumb carpometacarpal osteoarthritis: An anatomical and immunohistochemical study. Osteoarthritis Cartilage. Published 16 April 2026. doi:10.
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