Joint Line Obliquity Does Not Affect the Outcomes of Opening Wedge High Tibial Osteotomy at an Average 10-Year Follow-up

Abstract

Background: A significant number of high tibial osteotomies (HTOs) result in an overcorrected tibia and subsequent excessive lateral joint line obliquity (JLO). The correlation between excessive JLO and poor outcomes is controversial. Purpose: To evaluate the prognostic factors (including a pathological postoperative JLO) related with the outcomes of opening wedge HTO at 10 years of follow-up. Study Design: Case series; Level of evidence, 4. Methods: All patients undergoing HTO between 2004 and 2017 for medial osteoarthritis and with a postoperative hip-knee-ankle angle between 176° and 185° were included. Clinical evaluation included Knee Society Score (KSS; knee score and function score), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and visual analog scale for pain. Several mechanical and anatomic angles were measured pre- and postoperatively on long-leg weightbearing radiographs. Abnormal JLO was defined as a Mikulicz–joint line angle (MJL) ≥94° or a mechanical medial proximal tibial angle (mMPTA) ≥95°. Regression analysis was performed to evaluate the association between independent variables and each outcome. A Kaplan-Meier cumulative survival analysis was performed. Results: A total of 92 knees in 76 patients were included. The mean age of the patients was 53.5 years (SD, 9.7 years), and the mean follow-up was 129.4 months (SD, 44.4 months). Increased JLO was associated with a significant preoperative varus deformity (small preoperative hip-knee-ankle angle), increased mechanical lateral distal femoral angle, increased joint line congruency angle, and increased knee-ankle joint angle. Male sex was associated with better WOMAC scores ( P = .0277), and increased body mass index (BMI) was associated with inferior WOMAC scores ( P = .0024). A good preoperative range of motion was associated with better knee score ( P = .0399) and function score ( P = .0366) on the KSS. An increased BMI was associated with inferior KSS function scores ( P = .0317). MJL ≥94° and mMPTA ≥95° were not associated with inferior WOMAC or KSS outcomes. With indication to total knee arthroplasty as an endpoint, Kaplan-Meier analysis showed a survival rate of 98.7% at 5 years, 95.5% at 10 years, and 92.7% at 12 years. Conclusion: Increased lateral JLO (MJL ≥94° or mMPTA ≥95°) was not correlated with the clinical outcomes of opening wedge HTO at 10 years of follow-up.

Large Versus Small Opening Wedge High Tibial Osteotomies Performed With a Protective Wire Over the Lateral Hinge: Incidence of Lateral Hinge Fracture and Early Clinical Outcomes

“…This reduces shearing forces over the joint line as well as altered load stresses over the lateral tibial plateau. 3,15,34,38 However, preservation of joint line obliquity remains controversial, with some studies suggesting that it does not affect clinical outcomes owing to compensatory mechanisms 4,10,31 and with others reporting the opposite contrary. 1,34 There is evidence to suggest that type III fractures may occur because of abnormal loading over the lateral tibia, especially once patients commence weightbearing activities.…”

Preoperative Medial Tightness and Narrow Medial Joint Space Are Predictive Factors for Lower Extremity Alignment Change Toward Varus After Opening-Wedge High Tibial Osteotomy

“…The medial proximal tibial angle (MPTA) was defined as the angle between the tibial mechanical axis and articular surface of the proximal tibia. 29 , 33 , 40 The tibial slope was measured as the angle between the line perpendicular to the middiaphysis of the tibia and the line depicting the posterior inclination of the tibial plateau in the lateral view. 23 The medial joint space width was measured from the center of the MFC to the center of the MTP on the Rosenberg view, as described in a previous study.…”

Editorial Commentary: An Inverted V-Shaped High Tibial Osteotomy Combining a Lateral Closing Wedge and Medial Opening Wedge May Have Advantages

“…It also has been suggested that the IVHTO technique may be a good option for larger corrections. 9 Typically, larger corrections are achieved using either a single osteotomy in the coronal plane, accepting some postoperative joint line obliquity, or a double-level osteotomy, 11,12 which is more complex. The benefits of an IVHTO over these 2 options have yet to be proved, and indeed the results presented by Hayashi et al 10 show that the postoperative medial proximal tibial angle, a measure of joint line obliquity, was similar in their 2 groups: 94.5 AE 2.9 in the IVHTO group and 95.6 AE 2.7 in the CWHTO group.…”