Parallel K-Wire Placement Leads to Fusion and Midcarpal Settling in Scaphoid Excision Four-Corner Fusion

Abstract

Background: Scaphoid excision 4-corner fusion is a motion-sparing procedure in patients with advanced radioscaphoid arthritis. This study introduces an alternate technique for scaphoid excision 4-corner fusion using a parallel Kirschner wire (K-wire) construct across the midcarpal joints that leads to reliable fusion rates, and good patient outcomes. Methods: This is a single-surgeon, retrospective study of patients who underwent scaphoid excision 4-corner fusion, using a parallel K-wire construct across the midcarpal joints. Once fusion was achieved, K-wires were removed. Radiographic union rate, time to union, capitolunate angle, capitolunate coverage, and amount of midcarpal settling are measured. Patient-reported outcome measures and descriptive statistics are presented. Results: Sixty-five wrists were included in this study with a mean age of 50.1 years. One patient was lost to follow-up. All 64 wrists (100%) fused at an average of 2.6 months. The mean capitolunate angle was 7°, and capitolunate coverage was 99.2%. Fifty-two patients (81%) had adequate radiographs for measurement. Average midcarpal settling was 1.1 mm. Thirty-two patients (51%) were available for long-term follow-up at an average of 5.3 years (0.7-10.2 years), and participated in patient reported outcomes (PRO) surveys. The mean Quick Disabilities of the Arm, Shoulder, and Hand score was 16.6, and numeric pain rating scale score was 1.8. Conclusions: Parallel K-wire placement across the midcarpal joints with scaphoid leads to a high rate of fusion with good patient outcomes long term. Midcarpal settling that occurs through dynamic compression around the K-wires may have contributed to bony fusion. This technique may provide an alternative approach to achieving reliable fusion across the midcarpal joints.