Background: Carpometacarpal thumb arthritis causes pain and functional limitations. Methods: This study evaluated the efficacy of arthroscopic partial trapeziectomy with free palmar longus tendon suspension and interpositional arthroplasty, combined with a soft anchor internal brace, for the treatment of thumb basal joint arthritis. Between August 2010 and April 2020, 60 thumbs with symptomatic basal joint arthritis (Eaton stage II-III) were treated using this minimally invasive technique. Results: The cohort included 52 female and 8 male patients (mean age, 62.6 ± 4.3 years), who underwent clinical follow-up for 28.7 ± 3.0 months. VAS pain scores decreased from 5.7 ± 0.5 to 1.0 ± 0.7 and 7.1 ± 0.6 to 1.4 ± 0.9 (p < 0.001) during rest and activity, respectively. Thumb range of motion increased from 43.3 ± 11.3 to 54.2 ± 9.8 degrees, while pinch strength improved from 47.3 ± 9.5% to 88.8 ± 17.3% of the contralateral side (p < 0.001). Patients with Eaton stage II disease demonstrated better outcomes than those with stage III disease. Radiographically, minimal proximal migration of the first metacarpal (mean, 1.2 mm) was observed, with no cases of scaphotrapezial joint arthritis. Conclusions: Arthroscopic partial trapeziectomy with tendon suspension/interposition and an internal brace is an effective treatment for Eaton stage II-III basal joint arthritis, offering significant pain relief, functional improvement, and joint stability, while preserving the scaphotrapezial joint.
Keywords: arthroscopic partial trapeziectomy; carpometacarpal thumb arthritis; joint arthritis.