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

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.

High Tibial Osteotomy With Miniaci Planning Using Manual and Semiautomated Digital Measures

Background: Inadequate deformity analysis and planning before high tibial osteotomy (HTO) may result in correction errors with unsatisfactory clinical results. Indications: The purpose of this article is to describe the deformity analysis and preoperative planning before HTO. This surgery is effective for young patients with compartmental mild knee osteoarthritis. A partial deformity analysis without considering the femoral or intra-articular deformity may lead to overcorrection or excessive joint line obliquity. Preoperative planning using the Miniaci method with manual or semiautomated digital measures may help to prevent these types of errors. Technique Description: Landmarks are used at the proximal femoral side, distal condyles, proximal tibial plateau, and talus borders to define angles automatically on PeekMed software. Fujisawa point is determined to be 50% of the length of the proximal tibia, and Miniaci method is performed after defining the weightbearing line. The method can be performed manually or semiautomatically with the software. In this last case, the optimal procedure to be done to correct the malalignment is proposed by the software which automatically does the opening of the osteotomy to match the desired weightbearing axis and displays the size of the wedge in millimeters. Results: The intraobserver and interobserver reproducibility were performed by 2 different analyses and 2 different observers. The precision of the measures was confirmed based on computed tomographic (CT) scan 3-dimensional measures defined as the gold standard. All the intraobserver and interobserver reproducibility correlation coefficients and precision were satisfactory compared with the gold standard. Hip-knee-ankle angle may vary because of weightbearing situations between CT and long-axis x-rays. Discussion/Conclusion: The interest of semiautomated software for angular value measurements is now well recognized, and the inclusion of anatomical landmarks allows accurate and reproducible angular value measurements. Automatic knee osteotomy planning analyzes the metaphyseal deformity of both the tibia and the femur, and the software suggests the optimal procedure with the degree of openness to obtain the desired mechanical axis without creating excessive joint line obliquity

Association of Preoperative Tibial Varus Deformity With Joint Line Orientation and Clinical Outcome After Open-Wedge High Tibial Osteotomy for Medial Compartment Osteoarthritis: A Propensity Score–Matched Analysis

Background: The correction of lower limb deformity should be performed at the site of deformity to maintain knee joint orientation. However, the effectiveness of open-wedge high tibial osteotomy (OWHTO) for treatment of medial osteoarthritis in varus malalignment without definite tibial varus deformity has not been confirmed. Purpose/Hypothesis: This study aimed to compare the clinical and radiologic outcomes after OWHTO in patients without tibial varus deformity versus patients with tibial varus deformity after matching for confounding factors. We hypothesized that these outcomes would be inferior in patients without tibial varus deformity. Study Design: Cohort study; Level of evidence, 3. Methods: The outcomes of 133 OWHTO operations for medial osteoarthritis in 107 patients were retrospectively reviewed after follow-up for >2 years. The patients were divided into group 1 (tibia with varus deformity, preoperative medial proximal tibial angle [MPTA] <85°) and group 2 (tibia without varus deformity, preoperative MPTA ≥85°). The confounding factors, including patient characteristics, preoperative limb alignment, degree of osteoarthritis, and correction angle, were matched using propensity score matching. The radiologic parameters, including MPTA and joint line obliquity, were evaluated preoperatively, between 6 and 12 months postoperatively, and at the last follow-up. The radiologic outcomes were assessed using the medial joint space width and mechanical hip-knee-ankle angle. The clinical outcomes were evaluated by the Hospital for Special Surgery knee score, Knee Society Score (KSS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. The clinical and radiologic outcomes were compared between the groups. The proportions of patients achieving improvement in the clinical outcome beyond the minimal clinically important difference (MCID) or minimally important change were compared between the groups. Results: After propensity score matching, 32 patients were selected for each group. The mechanical hip-knee-ankle angle was corrected without significant difference from a mean ± SD varus angle of 8.0°± 3.3° to valgus angle of −3.2°± 2.5° in group 1 and from varus 8.0°± 3.6° to valgus −3.9°± 1.7° in group 2. The preoperative joint line obliquity was greater in group 2 as compared with group 1 (2.2°± 2.2° vs −0.4°± 1.8°, P < .001). With a similar 10° correction angle, the postoperative MPTA and joint line obliquity were 96.6°± 2.5° and 5.3°± 2.3°, respectively, in group 2, which were greater than 94.0°± 2.6° and 3.5°± 1.8°, respectively, in group 1 (both P < .001). The changes in joint space width and mechanical hip-knee-ankle angle were not significantly different between the groups over the follow-up period. At the last follow-up, the postoperative KSS objective score and WOMAC pain score in terms of symptom improvement were not significantly different between groups ( P = .092 and .068). However, the postoperative KSS and WOMAC functional scores were significantly worse in group 2 than in group 1 (77.3 ± 14.1 vs 84.4 ± 11.6, P = .044; 10.3 ± 9.2 vs 5.6 ± 7.2, P = .001). In group 1, 96.9% and 100% of patients showed improvements of >10 points in the KSS functional score and 15 points in the WOMAC functional score based on MCID or minimally important change. Meanwhile, 65.6% and 81.3% of patients in group 2, which were significantly lower than those of group 1, were improved beyond the MCID or minimally important change ( P = .001 and .024, respectively). Conclusion: In varus malalignment, the knee joint line was more oblique in patients without tibial varus deformity after OWHTO pre- and postoperatively. The clinical outcomes in terms of functional scores were inferior in patients without tibial varus deformity. However, the radiologic outcomes and symptomatic improvement after OWHTO were comparable regardless of the preoperative tibial varus deformity on midterm follow-up.

Knee Joint Line Obliquity Causes Tibiofemoral Subluxation That Alters Contact Areas and Meniscal Loading

Background: Little scientific evidence is available regarding the effect of knee joint line obliquity (JLO) before and after coronal realignment osteotomy. Hypotheses: Higher JLO would lead to abnormal relative position of the femur on the tibia, a shift of the joint contact areas, and elevated joint contact pressures. Study Design: Descriptive laboratory study. Methods: 10 fresh-frozen human cadaveric knees (age, 59 ± 5 years) were axially loaded to 1500 N in a materials testing machine with the joint line tilted 0°, 4°, 8°, and 12° varus (“downhill” medially) and valgus, at 0° and 20° of knee flexion. The mechanical compression axis was aligned to the center of the tibial plateau. Contact pressure and contact area were recorded by pressure sensors inserted between the tibia and femur below the menisci. Changes in relative femoral and tibial position in the coronal plane were obtained by an optical tracking system. Results: Both medial and lateral JLO caused significant tibiofemoral subluxation and pressure distribution changes. Medial (varus) JLO caused the femur to subluxate medially down the coronal slope of the tibial plateau, and vice versa for lateral (valgus) downslopes ( P < .01), giving a 6-mm range of subluxation. The areas of peak pressure moved 12 mm and 8 mm across the medial and lateral condyles, onto the downhill meniscus and the “uphill” tibial spine. Changes in JLO had only small effects on maximum contact pressures. Conclusion: A 4° change of JLO during load bearing caused significant mediolateral tibiofemoral subluxation. The femur slid down the slope of the tibial plateau to abut the tibial eminence and also to rest on the downhill meniscus. This caused large movements of the tibiofemoral contact pressures across each compartment. Clinical Relevance: These results provide important information for understanding the consequences of creating coronal JLO and for clinical practice in terms of osteotomy planning regarding the effect on JLO. This information provides guidance regarding the choice of single- or double-level osteotomy. Excessive JLO alteration may cause abnormal tibiofemoral joint articulation and chondral or meniscal loading.

Using the Lower Limb Adduction Angle to Predict Postoperative Knee Joint-Line Obliquity After Open-Wedge High Tibial Osteotomy

Background: Knee joint-line orientation is altered after open-wedge high tibial osteotomy (OWHTO), and excessive joint-line obliquity (JLO) can adversely affect outcomes. Little is known regarding preoperative prediction of postoperative knee JLO. Purpose/Hypothesis: The purpose of this study was to assess the correlation between the amount of lower limb adduction and changes in knee JLO after OWHTO. The hypothesis was that postoperative knee JLO could be predicted using the amount of lower limb adduction after OWHTO. Study Design: Case series; Level of evidence, 4. Methods: The records of 67 patients (77 knees) who underwent OWHTO for medial compartment osteoarthritis were retrospectively reviewed. The mechanical hip-knee-ankle (HKA) axis, lateral distal femoral angle, medial proximal tibial angle (MPTA), knee JLO, ankle JLO, and joint-line convergence angle were measured on standing whole-leg plain radiographs preoperatively and at 1 year postoperatively. The limb adduction angle was defined as the angle between the native weightbearing line (WBL) and the planned WBL on preoperative standing whole-leg plain radiographs. The predicted knee JLO was calculated as the sum of the preoperative knee JLO and the limb adduction angle. Multivariable linear regression analysis was used to identify the preoperative radiologic factors associated with the postoperative knee JLO. The agreement between postoperative and predicted values was determined using intraclass correlation coefficients (ICCs). Results: The estimated limb adduction angle was 4.2° ± 1.3°, and the predicted knee JLO was 4.9° ± 3.0°. The actual postoperative knee JLO was 4.5° ± 2.4°, which was a significant increase from 0.7° ± 2.4° preoperatively ( P < .001). Excellent agreement was found between the predicted knee JLO and postoperative knee JLO (ICC = 0.928; P < .001). Limb adduction angle and changes in preoperative MPTA were significantly associated with changes in knee JLO ( P < .001). On multivariable linear regression analysis, preoperative knee JLO and limb adduction angle were significantly associated with postoperative knee JLO ( P < .001; R 2 = 0.83). Conclusion: Changes in knee JLO after OWHTO were associated with adduction of the lower limb after OWHTO. During preoperative planning, postoperative knee JLO can be predicted as the sum of the preoperative knee JLO and the limb adduction angle between the preoperative WBL and planned WBL.

Two-level Osteotomy for Genu Valgum with Tibia Valga: Surgical Planning and Execution

Introduction: Proximal tibial injury leading to tibia valga which, in turn, leading to genu valgum is well described deformity. Management options vary between growth modulation and corrective osteotomy. Osteotomy which is used for skeletally mature patients can either be done in single stage or in multiple stages or in gradual manner. Case Report: We describe here a method to obtain single-stage correction with two-level osteotomy in a 20-year-old patient. It includes medial closing wedge osteotomy at distal femur and translational osteotomy at tibial shaft. Conclusion: This method of two-level osteotomy recognizes and treats two deformities (i.e., genu valgum and tibia valga) separately and achieves correction in one stage with perfect restoration of mechanical axis of lower limb and joint line obliquity of knee. Keywords: Genu valgum, tibia valga, double-level osteotomy, closing wedge osteotomy, translational osteotomy.

Is there difference and correlation between medial and lateral tibial plateau coronal obliquity in native knee? A radiographic study

Background/Purpose Knee joint line is commonly defined as a tangent to medial and lateral tibial plateaus in various radiographic measurements. We aim to investigate radiographic differences between medial and lateral knee joint line coronal obliquity. It has significant implication on radiographic analysis following unicompartmental knee arthroplasty. Methods We analysed the knee radiographs of 48 young patients (mean age 25.1 + /-5.6 years) with 50 anterior cruciate ligament-deficient knees. Medial and lateral tibial plateau coronal obliquity were defined as angles between femoral knee joint line and the tangent to articular surface of each tibial plateau. Mediolateral differences and linear correlation were analysed. Results Significant difference was found between medial (mean = -1.5, SD = 2.4 degrees) and lateral obliquity (mean = + 0.6, SD = 3.0 degrees) ( p < 0.001). The mean mediolateral difference was 3.1 degrees (SD = 2.8, range 0–11.8 degrees), without significant correlation (r = 0.085, p = 0.56). Conclusion Mediolateral differences exist in knee joint line obliquity. Each compartment should be considered separately when measuring knee joint line obliquity.