Validation of the Lift-Off Screw Technique in Patients Undergoing Corrective Osteotomy for Malunited Distal Radius Fractures.

Abstract

Purpose: The purpose of this study was to validate the clinical accuracy of the lift-off screw (LOS) technique for volar tilt correction (VTC) in patients undergoing corrective osteotomy for dorsally angulated distal radius fracture malunions.

Methods: We conducted a retrospective review of 23 patients with dorsally angulated distal radius fracture malunions treated with corrective osteotomy using the LOS technique. The LOS equation L_s = [tan(T_c) ∗ L_p + C]/[cos(⍬_s)] and standardized intraoperative fluoroscopic images were used to determine and compare the calculated and clinical VTC and final volar tilt. Correlations between the LOS length and the clinical VTC were calculated, as well as between the desired VTC and the correction accuracy.

Results: Preoperative volar tilt ranged from -6° to -50° (mean = -22.9° ± 10.6°). The calculated VTC was 32.7° ± 9.4°, and the clinical VTC achieved was 25.8° ± 9.3°. The difference between the clinical and calculated correction was -6.9°, with an average postoperative clinical volar tilt of 2.8° ± 5.7°, compared with a calculated volar tilt of 9.7° ± 4.4°. There was a moderately strong positive correlation between LOS screw length and clinical VTC achieved, and a moderately weak negative correlation between the desired amount of correction and the accuracy of the correction.

Conclusions: The LOS technique is a reproducible method to plan the amount of sagittal plane correction during corrective osteotomy surgery for dorsally angulated distal radius fracture malunions. We demonstrate that this technique underestimates the clinical correction achieved by an average of 7°, with larger deformities experiencing greater undercorrection. Undercorrection of volar tilt during corrective osteotomy should be anticipated by surgeons and considered in future implant and cutting guide designs.

Type of study/level of evidence: Therapeutic IV.