Optimal Position of the Suture Button Suspensionplasty (TightRope) for Thumb Basal Joint Arthritis.

Abstract

Background: Surgical treatment of basal joint arthritis commonly consists of trapeziectomy followed by various suspensionplasty techniques to provide stability to the thumb ray. Our study goal was to assess the motion and stability of the thumb ray after trapeziectomy and placement of a suture button (Mini TightRope®, Arthrex, Naples, Florida) in a high- or low-angle trajectory. We hypothesized that a low-angle trajectory would yield the greatest stability while providing maximal motion of the thumb. Methods: Eleven fresh-frozen cadaver arms were imaged fluoroscopically in anterior-posterior and lateral views before and after trapeziectomy, and after placement of low- and high-angle suture buttons. The intermetacarpal angle between the thumb and index metacarpals was measured after application of a standard force. Radial abduction, opposition, subsidence, palmar abduction, adduction, and subsidence were measured. Results: Compared to posttrapeziectomy constructs, low- and high-angle TightRope constructs demonstrated less subsidence, low-angle TightRopes had less palmar abduction, and high-angle TightRope constructs had less radial abduction and adduction. High-angle TightRopes allowed more palmar abduction than low-angle constructs. The high-angle TightRopes trended toward more subsidence than low-angle constructs, although it was not significant. Conclusions: Both TightRope constructs provided improved axial stability after trapeziectomy while not excessively limiting any one motion of the thumb. Compared to the high-angle trajectory, the low-angle TightRope placement provided a more stable construct with respect to subsidence and angular motion. Given the concern for excessive motion of the first metacarpal base with the high-angle construct, we recommend a low-angle trajectory TightRope placement.