Anatomic Feasibility of 4-Legged Staples for Naviculocuneiform Arthrodesis.

Abstract

Background: Naviculocuneiform (NC) arthrodesis is indicated for multiple pathologies, including degenerative and traumatic arthritis, progressive collapsing foot deformity, and medial column instability. Despite its broad application, no consensus exists regarding the optimal fixation construct. Shape-memory dynamic compression staples offer potential advantages in midfoot fusion compared to static fixation.

Purpose: To evaluate the feasibility of using 4-legged dynamic compression staples for NC arthrodesis and to characterize NC joint anatomy to guide implant selection and orientation.

Study design: Level IV cadaveric study.

Methods: Twenty fresh-frozen cadaveric lower limbs (10 pairs) were dissected to expose the NC joint. Measurements of the medial and intermediate cuneiform and navicular facets were recorded. Four-legged staples (26 and 30 mm) were inserted, and adjacent joints were examined for proximal or distal penetrance. Statistical analysis was performed using Mann-Whitney U tests with significance set at P ≤ .05.

Results: Staple fixation across the medial cuneiform-navicular articulation was safe in all 40 applications without talonavicular or tarsometatarsal breakthrough. In contrast, the intermediate segment demonstrated a significantly shorter length (35.83 ± 3.24 mm vs 46.40 ± 4.15 mm; P = .0002) and higher rates of talonavicular breakthrough at 20% for 26 mm staples and 60% for 30 mm staples. Longer intermediate segments correlated with reduced breakthrough (P = .0190).

Conclusion: To our knowledge, this is the first study to quantify NC articulation lengths. Four-legged staples up to 30 mm in length were shown to be feasible for use in both dorsal-to-plantar or medial-to-lateral orientations at the medial cuneiform articulation. Due to breakthrough with the 4-legged staples, 2-legged staples (16-20 mm bridge) and staple legs ≤20 mm are advised for the intermediate segment to minimize iatrogenic injury risk.Level of Evidence: Level IV Cadaveric Study.