18.2.5 - Prediction and Development of Preventive Strategies for Lateral Hinge Fracture During OW-HTO Based on Osteotomy Configurations
- H. Jeong (seongnam-si, KR)
- H. Jeong (seongnam-si, KR)
- H. Choi (seongnam-si, KR)
- Y. Lee (seongnam-si, KR)
Abstract
Purpose
The purpose of this study was to develop preventive strategies by identifying factors that affect LHFs. We hypothesized that (1) each LHF type would have different affecting factors and that (2) specific operative strategies that can contribute to the prevention of each LHF type can be developed.
Methods and Materials
We retrospectively analyzed 261 consecutive knees treated with biplanar OWHTO between March 2014 and December 2016. A total of 66 knees were diagnosed with LHF and subclassified into types I, II, III, and I-variant. Perioperative radiological variables that can affect LHFs were measured and divided into two categories, determined and modifiable (Figure 1).
A regression model was developed, and subgroup analyses were performed between the non-LHF group and each LHF group. The interval change of the weight-bearing line (WBL) ratio between postoperative 2 weeks and 1 year was performed for each LHF type.
Results
Every LHF types consist of several determined and modifiable factors. Type I LHF was possible to prevent by sufficient retro-tubercular thickness. For type II, thicker lateral distal fragment thickness and larger osteotomy-condylar angle that means higher starting point were important. For type III and I-variant, thicker lateral proximal fragment thickness and smaller retro-tubercular angle were important. The WBL ratio was decreased in type I LHF (p<0.001) and increased in type II (p=0.001) and I-variant (p=0.006) in serial assessment (Figure 2).
Conclusion
Unmodifiable and modifiable factors for the development of LHFs after OWHTO differ among LHF types. To prevent LHFs, the causes of each LHF must be identified, the patient’s specific geometry must be considered in the preoperative planning, and the surgical technique must be modified according to the modifiable factors. In addition, during the rehabilitation period after OWHTO, specific caution and closed observation are necessary for alignment changes related to each LHF type.