The benefits of a percutaneous supplemental screw to reinforce the hinge of a medial open wedge tibial osteotomy

Abstract

Introduction: Our earlier studies reported that an additional lag screw placed from the opposite side increases the stability of the fixation construct in medial open wedge high tibia osteotomy (MOWHTO). The aim of the study was to evaluate the clinical relevance of the use of a supplemental screw with immediate post-operative full weight-bearing and its benefits in terms of functional outcome, radiographic outcome and complications.

Materials and methods: A retrospective study was performed comparing the historical cohort (MOWHTO without opposite screw) (group A) with the current cohort (MOWHTO with opposite screw) (group B). The patients underwent clinical and radiological assessments. We evaluated the WOMAC (The Western Ontario and McMaster Universities) score, IKDC (International Knee Documentation Committee) scores, and Lysholm knee score. Patients' return to sports and work were also recorded.

Results: We included 123 knees receiving MOWHTO alone (group A) with 114 knees (group B) receiving MOWHTO with an opposite screw. A shorter bone union time (18.3 ± 2.1 weeks v.s. 11.5 ± 2.6 weeks, p < 0.001), earlier return to sports (6.1 months vs. 4.6 months, p < 0.001) and return to works (3.2 months vs. 2.3 months, p < 0.001) and better 6-month functional outcomes were found in group B (p < 0.001). The complications were similar in both groups. One patient experienced irritation at the site of the screw entrance and the screw was removed after union.

Conclusion: The current study evaluated the clinical efficacy of a supplemental lag screw placed from the opposite side in MOWHTO. Comparing to the plate alone, the additional opposite screw improved the implant and fixation stability under immediate weight-bearing without causing complications. A shorter time for returning to sports and work was noted, and a better functional outcome at 6-month follow-up was registered.

Keywords: Bone union; Functional outcome; Medial open wedge high tibial osteotomy; Opposite screw; Weight-bearing.