Ligament-Sparing Volar Radiocarpal Arthrotomy During Distal Radius Fracture Repair: Biomechanical Implications on Wrist Stability in a Cadaveric Model

Abstract

Purpose: Distal radius (DR) fracture fixation with volar locked plating typically uses indirect fracture reduction without direct visualization of the articular surface in an attempt to preserve the volar radiocarpal ligaments and prevent iatrogenic radiocarpal instability. This study assessed the biomechanical stability after a volar radiocarpal arthrotomy for direct articular visualization for DR fracture repair compared to a standard trans-flexor carpi radialis approach without arthrotomy in a cadaver model.

Methods: Ten fresh-frozen upper extremity matched-pair cadaveric specimens were tested. For each pair, one limb underwent trans-FCR approach with a volar arthrotomy that partially sectioned the long and short radiolunate ligaments to visualize the DR articular surface (Group 1). The contralateral limb underwent standard trans-FCR approach without arthrotomy (Group 2). Following capsular repair (Group 1), all specimens (Groups 1 and 2) underwent biomechanical testing, including axial loading (22.2 N, 44.5 N, 89.0 N, 177.9 N), volar translational, and dorsal translation loading (22.2 N, 44.5 N, 89.0 N) to assess carpal stability using both fluoroscopy and motion capture. Ulnar carpal translation was assessed using the Gilula method, measuring radiographic lunate overhang from the ulnar edge of the lunate fossa relative to the full width of the lunate. Dorsal and volar translation were assessed by measuring lunate overhang with respect to the dorsal or volar radial cortex. To simulate fractures with dorsal radiocarpal ligament disruption, the dorsal capsule was sectioned, and the biomechanical comparisons were repeated.

Results: Ulnar translation of the lunate remained below 2 mm for both groups in all testing scenarios. No significant differences were identified in ulnar, volar, or dorsal translation with increasing loads between the groups.

Conclusions: This volar ligament-sparing radiocarpal arthrotomy did not cause biomechanical radiocarpal instability.

Clinical relevance: This arthrotomy may provide enhanced visualization of the DR articular surface during fracture fixation without causing iatrogenic wrist instability.

Keywords: Distal radius fracture; radiocarpal arthrotomy; radiocarpal instability; volar wrist arthrotomy; wrist instability.