Implications of thumb position and trajectory in tetraplegia grip reconstruction - a cohort study.

Study design: This study represents a retrospective observational cohort study.

Objectives: The objective of this study was to investigate the impact of thumb position on postoperative patient-rated and functional outcomes in grip reconstruction surgery.

Setting: All consecutive adult patients with tetraplegia undergoing grip reconstruction surgery at the Swiss Paraplegic Centre between 06/2008 and 11/2020 were assessed for eligibility.

Methods: Standardized photo or film documentation was used for individually recreating and categorizing thumb position and trajectory during key pinch. Outcome measurements included key pinch strength, Canadian Occupational Performance Measure (COPM) and Grasp Release Test (GRT).

Results: Fifty-six hands of 44 patients (mean age 42.2 years, range 18-70 years) with a mean follow-up of 14.8 months (range 6 months to 12 years) were included. There was a significant postoperative improvement of key pinch strength, COPM score and GRT. COPM improvement was more pronounced for hands with more palmar abducted trajectories of the thumb.

Conclusions: Regardless of reconstruction type, pinch strength, patient satisfaction and grasp and release abilities improved significantly after surgery. Thumb position and trajectory are strong determining factors for the selected outcome measurements.