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

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.