Does the screw trajectory affect surgical outcomes in percutaneous fixation for subacute scaphoid fracture?

Scaphoid fractures are the most common fracture in carpal bone fracture. However, they are often overlooked in the acute stage, leading to delayed diagnosis. There is limited research on the treatment outcomes of subacute scaphoid fractures. While many biomechanical studies have investigated the optimal trajectory for fixing scaphoid fractures, their clinical relevance remains unclear. This study aims to explore the clinical outcomes of volar percutaneous fixation for subacute scaphoid fractures and compare potential outcomes between groups with perpendicular and non-perpendicular fracture-screw angles.

In subacute scaphoid fractures, there is no difference in clinical outcomes between the non-perpendicular group and the perpendicular group.

Between 2012 and 2022, 98 patients diagnosed with subacute scaphoid fractures were treated with volar percutaneous fixation within 3 weeks to 3 months post-injury. Acutrak mini headless compression screws (Acumed Inc., USA) were uniformly used. Included patients were divided into two groups: those with a fracture-screw angle ≥ 70 degrees formed the perpendicular group, while those with a fracture-screw angle < 70 degrees constituted the non-perpendicular group. Effective screw length was calculated. Clinical outcome assessment included wrist joint range of motion and Disability of the Arm, Shoulder, and Hand (DASH) scores recorded final follow-up visits. Union rate and union time were evaluated for radiologic assessment. Demographic and clinical outcomes were statistically compared between the two groups.

Basic demographic characteristics did not show statistically significant differences between the two groups. The fracture-screw angle differed significantly between the groups, with the perpendicular group having a mean angle of 83.5 ° (± 6.00) and the non-perpendicular group having a mean angle of 62.7 ° (± 2.40) (p < 0.001). The screw length used in the perpendicular group was 21.3 mm, while it was 23.1 mm in the non-perpendicular group (p < 0.001). There was no significant difference in the effective screw length between the two groups. The utilization of the trans-trapezial approach differed significantly between the groups, with 11.4% in the perpendicular group and 64.3% in the non-perpendicular group (p < 0.001). The union rate was 100% in both groups, and there were no notable complications. Both groups showed satisfactory outcomes in range of motion and clinical scores.

In patients with subacute scaphoid fractures, volar percutaneous fixation performed with appropriate indications achieved excellent outcomes. There was no significant difference in clinical outcomes between the perpendicular and non-perpendicular groups based on the fracture-screw angle. In cases where it is difficult to insert the screw perpendicularly, using a longer screw through a trans-trapezial trajectory can help achieve firm fixation.

III; Retrospective Case Control study.