Radiographic Thumb Metacarpal Subsidence Following Ligament Reconstruction With Tendon Interposition and Suture-Only Suspension Arthroplasty in the Treatment of Basal Joint Arthritis

Background: The thumb carpometacarpal (CMC) joint is a common source of osteoarthritis. Following trapeziectomy, ligament reconstruction with tendon interposition (LRTI) is considered a '' gold standard '' treatment, but suture-only suspension arthroplasty (SSA) has recently emerged as a simpler alternative. Currently, there is no objective radiographic study comparing subsidence following these 2 techniques. Methods: This study is a retrospective review of 23 patients (10 LRTI, 13 SSA) that had at least 6 months of radiographic follow-up following thumb CMC arthroplasty. Posteroanterior radiographs at a preoperative timepoint, and at the 2-week and greater than 6-month postoperative timepoints were evaluated for actual trapezial height, as well as trapezial height normalized to capitate, thumb metacarpal, and proximal phalangeal heights. Normalized trapezial heights were calculated, and preoperative values were compared with greater than 6-month postoperative values. In addition, actual and normalized trapezial heights following LRTI and SSA were compared at each timepoint. Results: Mean trapezial height decreased from approximately 12 to 5 mm (reduction of similar to 60%, P < .05) in both groups with no differences when comparing LRTI and SSA at each timepoint. All normalized trapezial heights revealed differences from preoperative to greater than 6-month postoperative timepoints, but no differences between LRTI and SSA. Conclusions: Ligament reconstruction with tendon interposition and SSA exhibit equivalent actual and normalized trapezial heights over a greater than 6-month postoperative time course.