Interosseous Membrane Reconstructions for Longitudinal Radioulnar Instability: A Cadaveric Comparison.

Background: Multiple options exist for reconstruction of the interosseous membrane (IOM) including biologic and nonbiologic materials. In this study, we present the biomechanical properties of reconstruction of the IOM using suture button suspension with and without pronator teres (PT) tendon rerouting.

Methods: Using 8 cadaveric specimens, radioulnar displacement was tested for the following successive conditions: intact specimen, IOM release with radial head (RH) resection, IOM reconstruction with PT tendon transfer alone, and PT transfer augmented with a suture button suspension construct with and without RH replacement. Specimens were cyclically loaded with 3 compression cycles to 130 N using a uniaxial materials test apparatus. Radioulnar displacement was the primary endpoint measured by the crosshead displacement. A repeated measure 1-way analysis of variance (ANOVA) and Tukey test was used for statistical analysis using P < .05.

Results: Interosseous membrane reconstruction with a PT soft-tissue graft supplemented with a suture button suspension construct with concomitant RH arthroplasty did not significantly decrease mean radioulnar displacement (PT Recon w/ RH: 2.99 ± 1.92 mm, TightRope w/ RH (2.88 ± 1.56 mm, P > .05). The use of suture button suspension augmentation did not significantly increase the stiffness of the PT IOM reconstruction construct when used concomitantly with an RH arthroplasty (PT Recon w/ RH: 82.48 N/mm, TightRope w RH: 71.51 N/mm, P > .05).

Conclusions: Pronator teres transfer with suture button augmentation effectively restores radioulnar stability. No significant differences in stability were observed between PT transfer with and without suture button suspension augmentation.