Effect of different distraction gaps in open wedge high tibial osteotomy on the mechanical distribution around the knee joint: A finite element analysis and clinical validation.

ObjectiveThe study aimed to investigate the mechanical distribution around knee joint after open wedge high tibial osteotomy (OWHTO) in different osteotomy distraction gaps (ODG) and confirm the safe ranges of correction after OWHTO.MethodsA three-dimensional finite element analysis (FEA) was performed to observe the max stress distribution for three compartments of knee joint in each OWHTO model under the different ODG (1, 1.5, 2, 2.5, 3 cm), and measure the joint line height (JLH), Blackburne Peel Index (BPI), Insall-Salvati index (ISI), and joint line convergence angle (JLCA). Moreover, a retrospective clinical study involving 50 patients underwent OWHTO (7 males with 8 knees and 40 females with 42 knees; aged from 42 to 67 years old, BMI ranged from 18.80 to 32.17 kg/m², duration from 12 to 38 months) was implemented to further reveal the role of different ODG on the clinical outcomes of patients after OWHTO.ResultsIn the FEA, the ODG after OWHTO were positively correlated with the JLH (R² = 0.980), negatively correlated with the BPI (R² = 0.995) and the JLCA (R² = 0.989), and not correlated with the ISI. Additionally, the turning point for the stress alterations of the three compartments of the knee joint was found when the ODG ranged from 2 to 2.5 cm. In the clinical study, a significant correlation was investigated between the two classifications (Kellgren-Lawrence and Iwano grading) and correction angle (r = 0.447, p < .001; r = 0.592, p < .001). A lower grading was observed in the correction angle within the range of 9-12°, compared with that in other ranges (χ² = 31.733, p < .001; χ² = 34.899, p < .001).ConclusionsThe ODG could affect the stress distribution of three compartments of the knee joint by altering the JLH, JLCA and BPI. As result of this, limited correction angle should be fully considered in the preoperative planning to avoid overcorrection and patellofemoral joint disorders.