Pilot Study: Changes in Metacarpophalangeal Joint Loading After First Metacarpal Osteotomy for Thumb Carpometacarpal Osteoarthritis.
- 1From the Department of Orthopaedic Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
- 2Division of Diagnostic Imaging, Department of Clinical Practice and Support, Hiroshima University Hospital, Hiroshima, Japan.
Abstract
Background
First metacarpal osteotomy is a joint-preserving option for thumb carpometacarpal osteoarthritis, but its effect on the adjacent metacarpophalangeal (MCP) joint remains unclear. We evaluated postoperative changes in MCP kinematics and subchondral stress distribution.Methods
We retrospectively analyzed 21 thumbs in 19 patients who underwent first metacarpal extension-abduction osteotomy. Assessments before surgery and at follow-up included pain and function, dynamic radiography of MCP motion, and computed tomography-based Hounsfield unit (HU) measurements as an index of subchondral bone density at 9 regions on the metacarpal head and proximal phalanx. Preoperative and postoperative data were compared with Wilcoxon signed-rank tests; regional HU distributions were assessed with Friedman tests and Dunn post hoc tests.Results
Median clinical follow-up was 1.5 years. Median MCP hyperextension improved from 16 (interquartile range [IQR], 5-28 degrees) to 0 degrees (IQR, 0-10 degrees; P < 0.01), whereas flexion did not change. Ulnar deviation at maximal palmar adduction increased from 8 (IQR, 5-10.5 degrees) to 12 degrees (IQR, 7-15 degrees; P = 0.011). One-year computed tomography showed significant postoperative HU decreases in dorsal regions of the metacarpal head, whereas the proximal phalanx showed no significant regional change. No radiographic progression of MCP osteoarthritis was observed.Conclusions
First metacarpal extension-abduction osteotomy improved MCP alignment and altered subchondral loading at the metacarpal head. These findings suggest that the procedure favorably affects thumb-ray biomechanics beyond the carpometacarpal joint.
Related
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BibTeX
@article{ishibashi2026pilot,
title = {{Pilot Study: Changes in Metacarpophalangeal Joint Loading After First Metacarpal Osteotomy for Thumb Carpometacarpal Osteoarthritis.}},
author = {Shigeki Ishibashi and Akira Kodama and Yuichi Sumida and Teruyasu Tanaka and Kazushi Yokomachi and Nobuo Adachi},
journal = {Plastic and reconstructive surgery. Global open},
year = {2026},
month = oct,
doi = {10.1097/gox.0000000000008213},
url = {https://europepmc.org/article/MED/42921368},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Pilot Study: Changes in Metacarpophalangeal Joint Loading After First Metacarpal Osteotomy for Thumb Carpometacarpal Osteoarthritis.
AU - Shigeki Ishibashi
AU - Akira Kodama
AU - Yuichi Sumida
AU - Teruyasu Tanaka
AU - Kazushi Yokomachi
AU - Nobuo Adachi
PY - 2026
DA - 2026/10/23
JO - Plastic and reconstructive surgery. Global open
DO - 10.1097/gox.0000000000008213
UR - https://europepmc.org/article/MED/42921368
AB - Background First metacarpal osteotomy is a joint-preserving option for thumb carpometacarpal osteoarthritis, but its effect on the adjacent metacarpophalangeal (MCP) joint remains unclear. We evaluated postoperative changes in MCP kinematics and subchondral stress distribution.Methods We retrospectively analyzed 21 thumbs in 19 patients who underwent first metacarpal extension-abduction osteotomy. Assessments before surgery and at follow-up included pain and function, dynamic radiography of MCP motion, and computed tomography-based Hounsfield unit (HU) measurements as an index of subchondral bone density at 9 regions on the metacarpal head and proximal phalanx. Preoperative and postoperative data were compared with Wilcoxon signed-rank tests; regional HU distributions were assessed with Friedman tests and Dunn post hoc tests.Results Median clinical follow-up was 1.5 years. Median MCP hyperextension improved from 16 (interquartile range [IQR], 5-28 degrees) to 0 degrees (IQR, 0-10 degrees; P < 0.01), whereas flexion did not change. Ulnar deviation at maximal palmar adduction increased from 8 (IQR, 5-10.5 degrees) to 12 degrees (IQR, 7-15 degrees; P = 0.011). One-year computed tomography showed significant postoperative HU decreases in dorsal regions of the metacarpal head, whereas the proximal phalanx showed no significant regional change. No radiographic progression of MCP osteoarthritis was observed.Conclusions First metacarpal extension-abduction osteotomy improved MCP alignment and altered subchondral loading at the metacarpal head. These findings suggest that the procedure favorably affects thumb-ray biomechanics beyond the carpometacarpal joint.
SN - 2169-7574
ER -