Medial opening wedge high tibial osteotomy (MOW-HTO) is a widely used surgical procedure for correcting knee alignment in patients with medial compartment osteoarthritis. A key concern with this technique is the risk of lateral hinge fractures (LHF), a complication that can lead to a loss of correction and negatively affect long-term patient outcomes. A new study investigates the impact of a protective wire on fracture rates in both large and small osteotomy corrections, offering valuable insights for orthopaedic surgeons.
Investigating the Role of the Protective Wire
Historically, the incidence of lateral hinge fractures has been reported as high as 30%, with larger corrections (distraction of more than 10mm) being particularly prone to this complication. However, recent advancements have focused on mitigating this risk. The study, a retrospective analysis of 96 knees that underwent MOW-HTO, aimed to investigate two key areas: the effectiveness of a protective guide wire in reducing LHF incidence across different correction sizes, and the effect of correction size on early clinical outcomes.
The cohort of patients was divided into two groups: Group A with small osteotomies (distraction less than 10mm) and Group B with large osteotomies (distraction of 10mm or more). All patients in the study had a protective wire inserted intraoperatively across the lateral hinge point prior to the opening wedge distraction. This technique is designed to reinforce the hinge, a critical part of the bone that acts as the pivot point for the correction.
Key Findings and Clinical Outcomes
The results were encouraging and highlight the benefit of using a protective wire. The incidence of lateral hinge fracture was low in both groups, at 6.1% for Group A and 9.1% for Group B. This suggests that the protective wire effectively reduces the risk of LHF, even in cases requiring a larger correction.
However, the study also revealed a difference in early clinical outcomes. At the six-month follow-up, patients with small corrections (Group A) showed statistically superior scores in several key metrics, including the Knee Score, Function Score, and Oxford Knee Score. This indicates that while the protective wire makes larger corrections safer, patients may experience a slower initial recovery compared to those with smaller corrections. Interestingly, by the two-year follow-up, the clinical outcomes between the two groups were comparable, suggesting that the initial differences in recovery diminished over time.
This research reinforces that the use of a protective wire is a reliable strategy for reducing lateral hinge fractures in MOW-HTO, regardless of the correction size. While patients with larger corrections may experience a more challenging initial recovery, the long-term outcomes are shown to be just as successful. These findings are essential for guiding surgical decision-making and setting realistic expectations for patients undergoing this joint-preserving procedure.
Professor Wilson’s Comments
“The hinge wire concept represented a major breakthrough in osteotomy surgery for both the femur and tibia. Building on the pioneering biomechanical work of Professor Matthieu Ollivier, which demonstrated a 900% increase in hinge stability with the addition of a protective wire, we were able to address one of the most critical complications in osteotomy surgery — hinge fractures.
Hinge fractures typically occur either intraoperatively or within the first six weeks postoperatively, significantly affecting patient recovery and outcomes. By introducing the hinge wire, we were able to stabilize the hinge, dramatically reduce the incidence of fracture, and crucially, allow patients to mobilize earlier and more confidently.
This foundational work led Kristian Kley and me to conceptualize and develop the hinge screw, which builds on the protective principles of the hinge wire while offering a more robust and reproducible fixation method. Today, the hinge screw has become standard of care in modern osteotomy surgery worldwide — a technique we co-patented and continue to use routinely in our practice.”
For a thorough examination of the full research and its findings, the complete paper is available for review:
