Comparison of Radiological and Clinical Efficacy of Normal and Overcorrected Varus Deformity After Medial Open Wedge High Tibial Osteotomy: A Two-Year Follow-up Investigation

Abstract Objective To study the clinical efficacy of over-correction of varus deformity 2 years after Open wedge High tibial osteotomy (OWHTO), and by using radiographic indicators, the compensatory changes of the hip, patellofemoral, and ankle joints were observed。 Methods Since February 2016, were retrospectively analyzed in August 2019 in our hospital during the period of treatment and included in the standard of 63 cases of patients with medial compartment osteoarthritis knee joint data, according to the postoperative measuring weight bearing line ratio（WBLR）, rectify all patients were divided into normal group, 52 cases (50% < WBLR < 67%) and excessive correct set of 11 cases (WBLR≥67% ),Measured at the end of the two groups of patients with preoperative and follow-up sessions Hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA), joint line convergence Angle (JLCA), Posterior tibial slope (PTS) after evaluating the effect of postoperative lower limb power line correction, measurement of Hip abduction angle (HAA), tibial plafond inclination（TPI）, Talar inclination Angle (TIA),Carton index, Lateral patellar tilt(LPT), Lateral patellar shift (LPS), medial patellofemoral space, and lateral patellofemoral space were used to evaluate the postoperative compensatory changes of the adjacent joints in the two groups. The American Hospital for Special Surgery score（HSS）, The Western Ontario and McMaster University Osteoarthritis Index（WOMAC） for the patients with knee arthrosis before and at the last follow-up, and the incidence of complications in patients at the last follow-up。 Results In the over-corrected group, the postoperative WBLR averaged (74.43±4.05) %, with 4 cases (36.36%) of postoperative complications, while in the normal corrected group, the postoperative WBLR averaged (55.76±4.88) %, with 6 cases (11.54%) of complications. The difference in postoperative complications between the two groups was statistically significant (P =0.041)。After OWHTO HKA compare two groups of patients at the end of the time, (7.39-1.61) ° for excessive correction group, (3.28-1.59) ° for normal correction group, difference was statistically significant (P = 0.000), compared two groups of patients at the end of the second MPTA, excessive correction group is (94.95 + 1.01) °, (91.1-2.87) ° for normal correction group, difference was statistically significant (P = 0.001), compared two groups of patients at the end of the time HAA, excessive correction group is (2.96 + 1.58) °, normal correction for (0.97 + 2.31) °,The difference was statistically significant (P=0.026), while the comparison of other imaging indicators showed no statistically significant difference. The results of surgical correction of the two groups were satisfactory, and the differences in the score of American Hospital for Special Surgery and the osteoarthritis index of The Western Ontario University and McMaster University were significant compared with those before surgery in the last follow-up (P < 0.05), and there was no statistical difference between the two groups in the last follow-up。 Conclusions Overcorrection of varus deformity (postoperative WBLR≥ 67%) did not affect the clinical outcome within 2 years after OWHTO, but increased the incidence of postoperative complications and resulted in increased compensatory adduction of the hip joint。