Among the various surgical treatments for basal joint arthritis, we modified abductor pollicis longus (APL) suspensionplasty by using two anchors. We hypothesized that this modification would prevent not only subsidence but also lateral migration of the first metacarpal. Thirteen thumbs that underwent APL suspensionplasty were investigated. Mean follow-up was 25 months (range, 12-69 months). Clinical and radiographic parameters were assessed preoperatively and postoperatively. Progression of subsidence (trapezial space) and lateral migration of the first metacarpal were investigated sequentially and with the thumb abducted or adducted against stress in a specifically designed mold. Clinical improvement was assessed by decrease in QuickDASH score (from 49.6 to 19.7). The immediate postoperative trapezial space decreased significantly by 39% (p = 0.003), and lateral migration was improved significantly by 14% (p = 0.007). At final follow-up, subsidence and lateral migration had not significantly progressed (p = 0.059 and 0.278, respectively). Under stress, the trapezial space ratio decreased significantly with the thumb in abduction (from 0.63 to 0.59, p = 0.011). APL suspensionplasty using two anchors in patients with basal joint arthritis maintained the position of the first metacarpal bone, and especially lateral subluxation. LEVEL OF EVIDENCE: IV.
