Adjusted planning based on the joint line convergence angle improves correction accuracy in the standing position after opening wedge high tibial osteotomy.

BACKGROUND: Postoperative change of the joint line convergence angle (JLCA) is known to be a factor affecting correction error in opening wedge high tibial osteotomy (OWHTO). The purpose of this study was to assess whether preoperative planning that considers change of the JLCA can achieve accurate correction in the standing position after OWHTO. METHODS: OWHTO was performed for 109 knees with osteoarthritis of the knee. The amount of angular correction was planned aiming to achieve mechanical valgus of 5° in 55 knees (conventional planning), and it was adjusted in 54 knees (adjusted planning) according to the preoperative JLCA as follows: not changed with JLCA ≤ 3°; decreased 1° with JLCA 4-6°; decreased 2° with JLCA 7-8°; and decreased 3° with JLCA ≥ 9°. The hip-knee-ankle (HKA) angle, JLCA, and medial proximal tibial angle (MPTA) were measured on standing long-leg radiographs. Correction error ≤ 2º was defined as the acceptable range, and correction error > 2º was defined as an outlier. RESULTS: The conventional planning group had a significantly greater postoperative HKA angle than the adjusted planning group (6.1º and 4.9º, respectively). The mean JLCA decreased from 4.8º to 2.6º in the conventional planning group and from 4.6º to 2.7º in the adjusted planning group. The conventional planning group had significantly greater postoperative MPTA than the adjusted planning group (96.2º and 94.7º, respectively). The rate of outliers with correction error > 2º was significantly lower in the adjusted planning group (9%) than in the conventional planning group (24%). The rate of the MPTA > 95º was significantly lower in the adjusted planning group (30%) than in the conventional planning group (69%). CONCLUSIONS: This study demonstrated that preoperative planning with adjustment of the correction angle according to the preoperative JLCA improved correction accuracy in the standing position after OWHTO.

The Osteotomy Gap Filling Rate of Multiple Time Points After Medial Opening Wedge High Tibial Osteotomy Without Bone Graft.

BACKGROUND: The purpose of the present study was to analyze osteotomy gap filling of multiple time points until 2 years post-medial opening wedge high tibial osteotomy (MOWHTO). The absolute value of gap filling and postoperative changes relative to the preoperative void osteotomy gap were evaluated using computed tomography (CT) at each time point. METHODS: Data of 30 patients who underwent MOWHTO between September 2019 and July 2021 were retrospectively analyzed. Surgical procedures without bone grafts were performed; a standardized rehabilitation protocol was implemented. The osteotomy gap filling rate was measured using computed tomography scans at the immediate postoperative period and at 6, 12, and 24 months after surgery. Statistical analyses were performed to assess changes over time. RESULTS: The osteotomy gap filling rate showed a significant continuous increase after MOWHTO, reaching 45.2% at 6 months and 66.7 and 84.4% at 1 and 2 years, postoperatively, respectively. The most substantial increase occurred within the initial 6 months, thus indicating a critical period for bone healing. CONCLUSIONS: The osteotomy gap filling rate showed a significant and gradual increase from immediately after surgery to 2 years after MOWHTO without bone grafting, the greatest of which was achieved in the initial 6-month period. Therefore, this study may be helpful for planning postoperative rehabilitation, including the extent of weight-bearing load and the period of crutch use. STUDY DESIGN: Case series; Level of Evidence IV.

Single-Joint Type Hybrid Assistive Limb for Knee Training in the Acute Postoperative Phase After Opening Wedge High Tibial Osteotomy: A Feasibility and Safety Trial.

BACKGROUND AND OBJECTIVE: Opening wedge high tibial osteotomy (OWHTO) influences the knee extensor mechanism, the range of passive motion of knee extension and persistent quadriceps, and anterior knee pain and weakness. Rehabilitation should focus on quadriceps strength and improving joint mobility. The single-joint hybrid assistive limb device (HAL-SJ) is a wearable exoskeleton cyborg. In this study, we investigated the feasibility and safety of HAL-SJ training after the early postoperative period following OWHTO and whether the use of this device can improve functional outcomes, including knee muscle extensor strength and knee extension range of motion without knee pain. METHODS: Patients who had been diagnosed with knee osteoarthritis and had undergone OWHTO were assessed for eligibility in this prospective trial conducted at our institution between June 2015 and November 2020. The participants were split into two groups, i.e., 10 patients in the hybrid assistive limb (HAL) group and eight patients in the control group. We initiated HAL-SJ therapy on postoperative day 8 and continued it until the patient's discharge. During the hospitalization period, patients engaged in HAL-SJ-assisted knee extension exercises. This exercise routine encompassed five sets, each comprising 10 repetitions, and was conducted twice a week. We conducted assessments aimed at detecting any potential adverse events that could be linked to HAL training. Assessment of the knee extension angle via the visual analog scale (VAS) and strength assessments using a hand-held dynamometer (HHD) were conducted. To compare clinical outcomes before and after OWHTO, knee extension angle, the VAS, HHD, Japanese Orthopaedics Association (JOA) score, and the Japanese Knee Osteoarthritis Measure (JKOM) were assessed at four distinct time points. RESULTS: No adverse events were observed during the study. The assessment of clinical outcomes before and after OWHTO demonstrated a gradual improvement in outcomes. CONCLUSION: The single-joint hybrid assistive limb device in patients who underwent OWHTO appears to be potentially safe. It contributed to enhanced muscle activity efficiency by reducing knee pain and improving knee extension angles in the early postoperative phase.

Postoperative improvement in patient-reported outcomes after neutral alignment medial open wedge high tibial osteotomy for medial compartment knee osteoarthritis in patients aged ≥70 years versus younger patients.

Purpose: To compare the postoperative clinical and radiological outcomes in patients aged ≥70 years following neutral alignment medial opening-wedge high tibial osteotomy (NA-MOWHTO) for medial compartment knee osteoarthritis (KOA) to those observed in younger patients. Methods: The data of patients who underwent NA-MOWHTO for medial compartment KOA between September 2018 and June 2022 were retrospectively analysed. The patients were categorised into groups Y (<70 years) and O (≥70 years). Age, sex, Kellgren-Lawrence classification, pre- and postoperative mechanical axis, weight-bearing line ratio, medial proximal tibial angle, preoperative Tegner Activity Score and pre- and postoperative Lysholm scores were compared between the groups. Results: Overall, 81 patients (60 and 21 in groups Y and O, respectively) who underwent NA-MOWHTO were included in this study. No significant differences were found in patient characteristics between the two groups, except for the preoperative Tegner Activity Score, which was significantly higher in group Y than in group O (3 [2-4] vs. 2 [2-2], respectively; p = 0.011). The two groups exhibited no significant differences in pre- and postoperative knee alignments. Postoperatively, Lysholm scores improved significantly in both groups without significant differences. Additionally, no correlation was found between age and pre- and postoperative Lysholm scores. Conclusions: The postoperative improvement following NA-MOWHTO for medial compartment KOA is comparable in patients aged ≥70 and younger. Level of Evidence: Level III, Retrospective comparative study.

The Role of Osteotomy in Anterior Cruciate Ligament Reconstruction.

Coronal and sagittal plane knee malalignments have been shown to increase the forces on anterior cruciate ligament (ACL) grafts after ACL reconstruction (ACLR). Studies have shown the benefit of high tibial osteotomy to address coronal and sagittal imbalance in revision ACLR. The purpose of this article is to further describe the use of osteotomy by reviewing preoperative planning, indications, techniques, and outcomes of high tibial opening and closing wedge as well as anterior tibial closing wedge osteotomies in the setting of ACLR.

Changes in Patellar Height and Tibial Posterior Slope after Biplanar High Tibial Osteotomy with Computer-Designed Personalized Surgical Guides: A Retrospective Study.

OBJECTIVE: Medial opening-wedge high tibial osteotomy (MOWHTO) is a surgical procedure to treat medial compartment osteoarthritis in the knee with varus deformity. However, factors such as patellar height (PH) and the sagittal plane's posterior tibial slope angle (PTSA) are potentially overlooked. This study investigated the impact of alignment correction angle guided by computer-designed personalized surgical guide plate (PSGP) in MOWHTO on PH and PTSA, offering insights for enhancing surgical techniques. METHODS: This retrospective study included patients who underwent 3D-printed PSGP-assisted MOWHTO at our institution from March to September 2022. The paired t-tests assessed differences in all preoperative and postoperative measurement parameters. Multivariate linear regression analysis examined correlations between PTSA, CDI (Caton-Deschamps Index), and the alignment correction magnitude. Receiver operating characteristic (ROC) curve analysis determined the threshold of the correction angle, calculating sensitivity, specificity, and area under the curve. RESULTS: A total of 107 patients were included in our study. The CDI changed from a preoperative mean of 0.97 ± 0.13 (range 0.70-1.34) to a postoperative mean of 0.82 ± 0.13 (range 0.55-1.20). PTSA changed from a preoperative mean of 8.54 ± 2.67 (range 2.19-17.55) to a postoperative mean of 10.54 ± 3.05 (range 4.48-18.05). The t-test revealed statistically significant changes in both values (p < 0.05). A significant alteration in patellar height occurred when the correction angle exceeded 9.39°. Moreover, this paper illustrates a negative correlation between CDI change and the correction angle and preoperative PTSA. Holding other factors constant, each 1-degree increase in the correction angle led to a 0.017 decrease in postoperative CDI, and each 1-degree increase in preoperative PTSA resulted in a 0.008 decrease in postoperative CDI. PTSA change was positively correlated only with the correction angle; for each 1-degree increase in the opening angle, postoperative PTS increased by 0.188, with other factors constant. CONCLUSION: This study highlights the effectiveness and precision of PSGP-assisted MOWHTO, focusing on the impact of alignment correction on PH and PTSA. These findings support the optimization of PSGP technology, which offers simpler, faster, and safer surgeries with less radiation and bleeding than traditional methods. However, PSGP's one-time use design and the learning curve required for its application are limitations, suggesting areas for further research.

The tipping point in medial opening wedge high tibial osteotomy relates to the shape of the proximal tibia more than to lower limb alignment correction.

PURPOSE: The tipping point (TP) of the knee joint is the centre of rotation of the joint in the coronal plane. This study aimed to define the TP in medial opening wedge high tibial osteotomy (MOWHTO). METHODS: Data from 154 consecutive patients with varus knee malalignment, who underwent MOWHTO between 2017 and 2021, was retrospectively reviewed. The degree of preoperative osteoarthritis (OA), using the Kellgren-Lawrence (KL) grading system, was recorded. Long-leg standing radiographs were used to record the alignment parameters, including the hip-knee-ankle angle (HKA), the mechanical lateral distal femoral angle (mLDFA), the medial proximal tibial angle (MPTA), the joint line convergence angle (JLCA) and the joint line obliquity (JLO) angle. Postoperative Tegner activity scores, Western Ontario and McMaster University Scores and patients' satisfaction were recorded. To define the TP, the relationship of all variables to Δ JLCA (absolute difference between preoperative to postoperative JLCA values) was analysed. Linear regression was employed for Δ JLCA to preoperative JLCA and postoperative and Δ MPTA (absolute difference between preoperative and postoperative values). K-means clustering was used to partition observations into clusters, in which each observation belongs to the cluster with the nearest mean serving as a prototype of the cluster, and analysed if there was any specific threshold influencing Δ JLCA. After defining the TP, further subanalysis of the TP based on the preoperative KL OA grade and analysis of variance of this TP to the KL OA grade was performed. RESULTS: A total of 154 patients (77.9% males and 22.1% females) were included. The mean age was 48.2 ± 11 years, and the mean body mass index was 27.1 ± 4 kg/m2. Preoperatively, 26 (16.9%) patients had KL grade IV OA. The mean preoperative and postoperative JLCA and the significance of their relation to Δ JLCA were 2.6° ± 1.8° (p < 0.0001) and 1.9° ± 1.8° (p = 0.6), respectively. The mean Δ JLCA was 1.4° ± 1.5°. The mean pre- and postoperative MPTA and the significance of their relation to Δ JLCA were 84.6 ± 2.2 (p = 0.005) and 91.8 ± 2.5 (p < 0.0007), respectively. The mean Δ MPTA was 7.2 ± 2.3 (p = 0.3). The mean preoperative and postoperative HKA and the significance of their relation to Δ JLCA were 174.6 ± 2.5 (p = 0.2) and 181.9 ± 2.4 (p = 0.7), respectively. The overall linear regression for Δ JLCA was statistically significant for preoperative JLCA (R2 = 0.3, p < 0.0001) and postoperative MPTA (R2 = 0.09, p = 0.0001) and statistically insignificant for Δ MPTA (R2 = 0.01, p = 0.2) and postoperative HKA (R2 = 0.04, p = 0.7). MPTA > 91.5° was the optimal threshold dividing this series data set between substantial and nonsignificant Δ JLCA. CONCLUSION: In this study, the main predictive factors for intra-articular correction (Δ JLCA) after MOWHTO were the preoperative value of JLCA and the postoperative value of MPTA. A value of 92° for postoperative MPTA is potentially the optimal threshold to predict intra-articular correction. LEVEL OF EVIDENCE: Level IV, retrospective cohort study.

Development of a machine learning model for identifying the optimal situation favoring double-level osteotomy over single-level high tibial osteotomy.

BACKGROUND: This study aimed to develop a machine learning (ML) model to identify the optimal situation wherein double-level osteotomy (DLO) is favored for severe varus knees by analyzing unfavorable outcomes. This study hypothesized that there are the most favorable algorithms and contributing factors for identifying the optimal situation favoring DLO over opening-wedge high tibial osteotomy (OWHTO). METHODS: Data were retrospectively collected from patients who underwent OWHTO (505 knees). Unfavorable outcome parameters were defined as follows: (1) medial proximal tibial angle (MPTA) > 95°, (2) joint line convergence angle (JLCA) > 4° (insufficient medial release), (3) JLCA < 0° (medial instability), (4) recurrence of varus deformity, and (5) lateral hinge fracture. The input data for the ML model included demographic data and preoperative radiological and intra-operative factors. The ML model was used to evaluate overall and to evaluate each unfavorable outcome. Interpretation by the model was performed by SHapley Additive exPlanations. RESULTS: The unfavorable group had a larger JLCA and MPTA preoperatively than the favorable group in the conventional comparison. The light gradient boosting machine (LGBM) demonstrated the highest AUC of 0.66 and F-1 score of 0.72 among the ML algorithms. In the overall assessment, the preoperative weight-bearing line ratio (WBLR) was the factor that contributed the most, followed by the preoperative JLCA and the ΔWBLR. ΔWBLR and the preoperative JLCA were the contributing factors for each outcome. CONCLUSIONS: The LGBM model was superior in predicting the optimal situations favoring DLO over OWHTO. Preoperative WBLR, preoperative JLCA, and ΔWBLR significantly contributed to the unfavorable outcomes overall and for each outcome in the ML model.

Economic evaluation of high tibial osteotomy: Closing wedge is more cost-effective than open wedge technique when analysing the KOOS-12 improvement.

PURPOSE: The purpose of this study was to compare the cost-effectiveness of two techniques for performing a knee valgus osteotomy: opening wedge high tibial osteotomy (OW-HTO) vs closing wedge high tibial osteotomy (CW-HTO). METHODS: In this economic evaluation study, a cost-effectiveness analysis from the perspective of the Spanish public healthcare system was performed, comparing OW-HTO with CW-HTO. All patients with medial knee osteoarthritis who underwent one of these procedures between 2018 and 2020 in our institution were included. The cost analysis included operating room, implant, graft and hospital admission costs. Functional outcomes (KOOS-12, Tegner activity scale, pain and satisfaction) and radiological outcomes (hip-knee-ankle angle, medial proximal tibial angle, tibial slope and patellar height) were analysed. The cost-effectiveness ratio was obtained by calculating the cost of improving the minimal clinically important difference (MCID) of KOOS-12 for each procedure. All costs are expressed in 2020 euros. RESULTS: Fifty-one patients met the inclusion criteria (27 OW-HTO and 24 CW-HTO). Good to excellent functional outcomes, significant pain reduction (>6 points) and high patient satisfaction (>9/10) were observed in both groups. Both techniques yielded excellent radiological outcomes. N.s. differences in functional or radiological outcomes improvements between both procedures were found. However, the OW-HTO group presented a higher total cost than the CW-HTO group (4612.1 ± 765.6€ vs. 1827.1 ± 701.9€; p < 0.001). The cost-effectiveness ratio was 818.1 ± 46.8 €/MCID for the CW-HTO procedure and 2414.3 ± 115.2 €/MCID for the OW-HTO procedure (p = 0.025). CONCLUSION: The CW-HTO procedure presented a cost-effectiveness ratio almost three times lower than the OW-HTO procedure. Both techniques allowed to achieve of good to excellent functional outcomes, significant pain reduction and high patient satisfaction while correcting the varus limb malalignment and the metaphyseal tibial varus in patients with medial compartment osteoarthritis. LEVEL OF EVIDENCE: Level III; economic study.

Medial opening wedge high tibial osteotomy for the treatment of medial unicompartmental knee osteoarthritis: A state-of-the-art review.

Medial unicompartmental knee osteoarthritis is a common condition that is frequently associated with significant pain and dysfunction. Medial opening wedge high tibial osteotomy (MOWHTO) offers a unique opportunity to preserve the knee joint and potentially alter the course of the degenerative process. Recent advances in this field of surgery have enabled surgeons to perform a MOWHTO in a safe, reliable and reproducible manner. This state-of-the-art review highlights the most important advances in the field of MOWHTO. Key concepts related to patient selection, pre-operative planning, surgical accuracy and patient outcome are considered. The importance of an individualized approach is emphasized and its influence on the future direction of the procedure is discussed.

Analysis of radiographic factors affecting the significant differences in knee alignment between hip-to-talus and hip-to-calcaneus radiographs after opening-wedge high tibial osteotomy.

BACKGROUND: Optimal alignment after opening-wedge high tibial osteotomy (OWHTO) is crucial for obtaining good clinical results. A hip-to-calcaneus radiograph (HCR) appears to reflect the true mechanical axis. However, no study has been reported using the HCR in patients who underwent OWHTO. We aimed to analyze the radiographic factors affecting the significant difference in the weight-bearing line (WBL) ratio between two radiographs after opening-wedge high tibial osteotomy (OWHTO). METHODS: This retrospective study included 51 patients who underwent both hip-to-talus radiographs (HTR) and HCR after OWHTO. The patients were divided into two groups; a consistent group (WBL ratio difference between postoperative HTR and HCR < 5%; N = 35) and an inconsistent group (> 5%; N = 16). Radiographic variables for lower extremity alignment, knee and ankle joints, and clinical scores were evaluated. The receiver operating characteristic curve was used to determine the threshold of radiographic variables that induced inconsistencies between the two radiographs. RESULTS: The mean postoperative WBL ratio in the HCR of the inconsistent group was significantly higher than that of the consistent group (57.7 ± 13.2% and 49.1 ± 11.6%, respectively) (P = 0.02). The preoperative and postoperative ankle joint line obliquity (AJLO) and preoperative lateral distal tibia ground surface angle (LDTGA) were significantly different between the two groups (P < 0.05). The preoperative AJLO (odds ratio 0.784, confidence interval 0.655-0.939, P = 0.008) significantly affected WBL ratio inconsistency. The cutoff value of the preoperative AJLO was 3.16°. However, clinical scores did not differ significantly between the two groups. CONCLUSION: The pre-and postoperative AJLO and the preoperative LDTGA were significantly different between the two groups. Among these variables, only preoperative AJLO negatively affected the inconsistency in WBL ratios between the two radiographs (HTT and HTC). Therefore, it should be considered to prevent postoperative overcorrection of the true mechanical axis after OWHTO, even though we corrected it properly. Level of evidence Level IV.

Maintaining Posterior Tibial Slope and Patellar Height During Medial Opening Wedge High Tibial Osteotomy.

Background: Increased posterior tibial slope (PTS) and decreased patellar height (PH) after medial opening wedge high tibial osteotomy (MOWHTO) have been repeatedly reported in the literature. However, this has been disputed in more recent biomechanical studies. Hypothesis: No change in PTS or PH would result after MOWHTO with the freehand technique, regardless of the degree of the coronal plane correction. Study Design: Case series. Methods: A total of 62 patients who underwent MOWHTO between 2018 and 2020 were included. Surgery was performed using a dedicated step-by-step protocol to reduce the risk of unintentional slope changes. All patients were evaluated preoperatively and at a 2-year follow-up with the Knee injury and Osteoarthritis Outcome Score and the University of California, Los Angeles physical activity scale. Pre- and postoperative radiographic lower limb alignment parameters-including hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle, proximal posterior tibial angle (PPTA), joint line convergence angle, and joint line obliquity-were measured on full-length lower limb radiographs. PH measurements assessed on lateral and anteroposterior knee radiographs included the Caton-Deschamps, Insall-Salvati, and Schröter indices. Results: A significant change was observed in the coronal plane alignment, with an increase in the MPTA from 84.38° to 90.39° (P < .001) and a consequent increase in the HKA from 172.19° to 180.15° (P < .001). No significant changes were observed in the PTS, as evidenced by a postoperative PPTA of 80.6° versus a preoperative value of 80.4° (P = .2). No significant changes were detected in the mean PH on all 3 indices used-pre- versus postoperative Caton-Deschamps, Insall-Salvati, and Schröter indices measured 0.95 versus 0.93 (P = .2), 1.03 versus 1.03 (P = .5), and 1.56 versus 1.54 (P = .3), respectively. Conclusion: In this study, MOWHTO did not result in significant changes in the PTS or PH when accurate preoperative planning and precise intraoperative freehand technique were adopted..

Repair of medial meniscus posterior root tear is effective for root healing and cartilage regeneration in opening wedge high tibial osteotomy.

PURPOSE: This study aimed to determine whether the repair of a medial meniscus posterior root tear (MMPRT) is effective for MMPRT healing, cartilage regeneration, and clinical outcomes in opening wedge high tibial osteotomy (OWHTO). METHODS: This retrospective study included 80 patients who underwent OWHTO and subsequent second-look arthroscopy. The patients were divided into OWHTO-with-MMPRT-repair (n = 40) and OWHTO alone (n = 40) groups, and the healing rates (complete/partial/failure) were compared. Each group was further divided into over- and under-corrected subgroups to compare healing rates. The International Cartilage Repair Society (ICRS) grade, cartilage defect size, Koshino stage, ICRS cartilage repair assessment score of the medial femoral condyle (MFC), and International Knee Documentation Committee (IKDC) scores between the OWHTO-with-MMPRT-repair and OWHTO alone groups were compared according to whether microfracture was performed on the MFC. RESULTS: The overall healing rate of the MMPRT was higher in the OWHTO-with-MMPRT-repair group than that in the OWHTO alone group (P < 0.001). In addition, in the subgroup analysis, no difference in the MMPRT healing rate between the over-correction and under-correction groups when MMPRT repair was performed (n.s). In contrast, without MMPRT repair, the healing rate was lower in the under-correction group than that in the over-correction group (P = 0.03). Cartilage regeneration of the OWHTO-with-MMPRT-repair group was superior to that of the OWHTO alone group (P < 0.05). The IKDC subjective scores of the OWHTO-with-MMPRT-repair and OWHTO alone groups were 34.5 and 33.1 before surgery (n.s) and 50 and 47.2 at one year after surgery, respectively (n.s). These differences between the two groups for cartilage regeneration and IKDC subjective scores showed the same pattern regardless of microfractures. CONCLUSIONS: MMPRT repair during OWHTO might improve MMPRT healing, even with under-correction, and cartilage regeneration of MFC, regardless of microfracture. However, OWHTO with MMPRT repair might not improve short-term clinical outcomes compared to OWHTO alone. Further randomized clinical trials are necessary. LEVEL OF EVIDENCE: III, Retrospective cohort study.

Changes in ankle and hip joints following medial opening-wedge high tibial osteotomy affect knee joint line obliquity.

PURPOSE: This study aimed to measure the change in knee joint line obliquity (KJLO) and the changes in radiologic parameters of the ankle and hip joints after medial opening-wedge high tibial osteotomy (MOWHTO), and to evaluate the correlation and causal relationship between these parameters. METHODS: This study evaluated 109 patients who underwent MOWHTO between April 2015 and December 2021. Radiologic parameters, including KJLO, medial proximal tibial angle (MPTA), ankle joint line obliquity (AJLO), and hip abduction angle (HAA), were analysed before and 1 year after MOWHTO. Multiple linear regression analysis was used to identify independent variables that significantly affected the change in KJLO after MOWHTO. Receiver operating characteristic (ROC) analysis was used to evaluate the cutoff value for a change in KJLO that exceeded 5° postoperatively, and the predicting values of radiologic parameters. RESULTS: Multiple linear regression analysis showed that changes in MPTA, AJLO, and HAA (ß = 0.440, P < 0.001; ß = - 0.310, P < 0.001; ß = 0.164, P = 0.035, respectively) were predictors of the change in KJLO after MOWHTO. ROC analysis showed that the threshold value for a change in KJLO which exceeded 5° postoperatively was 4.6° (66.7% sensitivity, 63.8% specificity, P = 0.025). Moreover, ROC curves for predicting a change in KJLO of > 4.6° showed that the AUC was significantly higher for the change in MPTA than that of the other two parameters (P = 0.011 for AJLO and P < 0.001 for HAA). CONCLUSION: MOWHTO increases the KJLO by valgization of the proximal tibia and causes hip adduction and ankle valgization. The postoperative ankle valgization after MOWHTO could reduce the increase in KJLO, counteracting the effects of proximal tibial valgization and hip adduction. Therefore, the effects of the hip and ankle joints should be considered to achieve an optimal KJLO and satisfactory clinical outcomes after MOWHTO. LEVEL OF STUDY: Cohort study, IV.

Better clinical outcomes and faster weight bearing after medial opening-wedge high tibial osteotomy using allogeneic than synthetic graft: A secondary analysis of a Francophone Arthroscopy Society Symposium.

INTRODUCTION: Although an autogenous graft has the highest rate of bone union to fill the void created in medial opening wedge high tibial osteotomy (MOWHTO), it also has some disadvantages, such as prolonged surgical time, donor site pain and morbidity. Two possible candidates for ideal grafts to replace autogenous grafts are allogeneic and synthetic graft, which are free from donor site pain and morbidity. However, previous reports comparing the clinical results of allogeneic to synthetic graft have been limited and controversial. The purpose of this study is to compare radiological findings and clinical outcomes of using synthetic versus allogenic graft to fill the void created in MOWHTO. HYPOTHESIS: The present clinical study hypothesized that allogenic graft to fill the void would allow the higher rate of bone union and better clinical outcomes. MATERIAL AND METHODS: This study compared the clinical and radiological outcomes of 95 patients who received MOWHTO to fill the void with either synthetic or allogenic graft (44 in Syn group, 51 in Allo group). Preoperatively and postoperatively, all patients were clinically evaluated; Return to work, Tegner activity score, and the Western Ontario and Macmaster University scores were reported. Radiographically, osteoarthritis grade and pre- and postoperative parameters were reported, including Hip-knee-ankle angle, mechanical lateral distal femoral angle, medial proximal tibial angle, joint line convergence angle, proximal posterior tibial angle, and limb length discrepancy. Perioperative details and complications were also reported. RESULTS: Mean follow-up (months) were 24.0±1.3 in Syn group and 26.8±1.2 in Allo group (p=0.13). The postoperative improvement of pain and global WOMAC scores in Allo group were significantly better than in Syn group (ΔPain of WOMAC: Syn group 27.8±4.4, Allo group 49.3±3.8, p value <0.001*) (ΔGlobal score of WOMAC: Syn group 16.7±3.2, Allo group 37.4±4.9, p value=0.002*). The risk of hinge fracture in Syn group was significantly higher than in Allo group (Hinge fracture by Takeuchi grade (0/1/2/3): Syn group 37/3/3/1, Allo group 43/8/0/0, p value=0.04*). The timing of full weight bearing in Allo group was significantly earlier than in Syn group (Weight Bearing (1=FWB, 2=PWB 3wk, 3=PWB 6wk): Syn group 2.7±0.1, Allo group 2.3±0.1, p value=0.01*). DISCUSSION: The use of allogenic graft to fill the void in MOWHTO does not show superiority in bone union compared to synthetic graft, however it improves pain, function, decreases the risk of hinge fracture and allows faster weight bearing than synthetic graft. LEVEL OF PROOF: III; Case-control study.

Bilateral Knee Osteoarthritis Treated With Medial Open-Wedge High Tibial Osteotomy Using Two Types of ß-Tricalcium Phosphate With Differing Placements in Each Knee: A Report of Two Cases.

In medial open-wedge high tibial osteotomy (MOWHTO) for knee osteoarthritis, synthetic bone is commonly used as a replacement material for the opening gap. Unidirectional porous ß-tricalcium phosphate (UDPTCP) and spherical porous ß-tricalcium phosphate (SPTCP) have been widely used in this regard. In general, the two prostheses are placed parallel to the osteotomy opening gap. In this report, we discuss two cases involving a 63-year-old woman and a 51-year-old man who underwent MOWHTO for bilateral knee osteoarthritis. Both patients had experienced bilateral knee pain. In both patients, UDPTCP was placed anteriorly and SPTCP was placed posteriorly in one knee, with the placement reversed in the other knee. The remodeling of each type of ß-TCP was evaluated using CT immediately after the surgery and one year postoperatively. The postoperative corrective loss and clinical outcomes were also evaluated. Remodeling with ß-TCP was found to be faster with UDPTCP than with SPTCP, even though the anteroposterior placement differed laterally in each patient. Furthermore, there was no correction loss, and the clinical outcomes were comparable, regardless of the placement of ß-TCP.

Clinical and radiological outcomes of medial opening-wedge monoplanar and biplanar high tibial osteotomy using a triangular allograft impaction technique: A retrospective single centre study.

PURPOSE: The aim of the study was to research the clinical and radiological outcomes between monoplanar and biplanar medial opening-wedge high tibial osteotomy. We hypothesized that there would be no differences between both techniques when using a triangular allograft impaction technique. METHODS: A single-centre, observational, retrospective study was conducted on 103 opening-wedge high tibial osteotomy patients from January 2017 to September 2019. Data collection, NRS and KOOS-PS, was performed preoperatively, 3 months and 12 months postoperatively. Radiological assessment (Kellgren-Lawrence, mechanical femoral-tibial angle, posterior tibial slope angle, lateral patellar tilt, patellar height) was performed on standing radiographs. RESULTS: In total 32 patients were included in the biplanar group and 71 patients in the monoplanar group. NRS and KOOS-PS scores improved significantly (p < 0.001) in time for both groups from baseline to 3 m PO and further to 1 year postoperatively. Our results showed no differences in radiological outcomes such as patellar height, LPT and posterior tibial slope angle. The monoplanar group did have more Takeuchi I and III fractures and a higher mFTA angle without clinical repercussion. CONCLUSIONS: Using a triangular allograft impaction technique for monoplanar and biplanar medial opening-wedge high tibial osteotomy gives no differences in clinical (NRS and KOOS) and radiological outcomes. Although a difference in Takeuchi fractures was found for monoplanar patients, no additional fixation was necessary, nor did clinical complications occur. We can conclude that triangular allograft impaction technique creates a stable construct and standardizes the healing procedure postoperatively for both monoplanar and biplanar medial opening-wedge high tibial osteotomy.

Lateral hinge fracture in medial opening wedge high tibial osteotomy: a narrative review.

Lateral hinge fractures (LHF) are one of the most common complications of medial opening wedge high tibial osteotomy (MOWHTO), and are the leading cause of construct instability displacement, non-union, and varus recurrence after this procedure. To date, Takeuchi's classification is the most popular classification to describe this complication, and it can help surgeons to make intra and postoperative decisions. Opening medial gap width is the most recognized factor related to LHF occurrence. Recognizing the implications of LHF in patients' clinical and radiographic results has led many authors to propose surgical tips and the use of osteosynthesis materials such as K-wires and screws for its prevention, which should be considered when identifying risk factors for LHF during preoperative planning. The evidence for determining the optimal management of LHF is scarce and mostly supported by experts' opinions and recommendations; therefore, studies are still needed to identify the most appropriate behavior when dealing with such a complication.

Effect of Prior Knee Arthroscopy on Midterm Outcomes After Medial Opening-Wedge High Tibial Osteotomy: A Propensity Score-Matched Analysis.

Background: Knee arthroscopy is frequently performed to improve joint function and relieve pain. However, there is no consensus regarding the effect of prior arthroscopy on outcomes following medial opening-wedge high tibial osteotomy (MOWHTO). Purpose: To compare midterm clinical outcomes and survival rates after MOWHTO between patients with and without a history of knee arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: We enrolled patients who underwent MOWHTO between March 2008 and February 2017 and had ≥4 years of follow-up. Patients who had undergone knee arthroscopy were included in an arthroscopy group, and those who had not were included as controls. After propensity score matching based on age, sex, body mass index, and lesion size, 80 patients in each group were included. Clinical outcomes were assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS), 36-Item Short Form Health Survey, and Tegner Activity Scale. Furthermore, survival rates and relevant risk factors that affected joint survivorship were analyzed, wherein conversion to total knee arthroplasty was considered the endpoint. Results: Although the pre- to postoperative improvement in clinical outcomes did not differ significantly between the groups, there were significant between-group differences in final postoperative scores on the KOOS-Activities of Daily Living (arthroscopy vs control, 78.1 ± 10.6 vs 81.0 ± 9.8; P = .031), KOOS-Sport and Recreation (45.4 ± 12.8 vs 48.7 ± 13.5; P = .045), 36-Item Short Form Health Survey Physical Component Summary (65.1 ± 12.7 vs 69.3 ± 11.8; P = .017), and Tegner Activity Scale (4.1 ± 1.1 vs 4.5 ± 1.0; P = .007). The survival rate was 96.8% at a mean follow-up of 8 years, and survival was not associated with a history of arthroscopy (P = .697; log-rank test). Conclusion: Although patients with prior arthroscopy had some inferior patient-reported outcome scores after MOWHTO, the overall clinical improvements were similar in the arthroscopy and control groups.

Decision regret following opening wedge high tibial osteotomy: Older age as a risk factor.

BACKGROUND: Understanding risk factors that can predict decision regret after surgical procedures can potentially increase the quality of patient decision making and reduce decision regret after opening wedge high tibial osteotomy (OWHTO). The purpose of the present study was to identify the risk factors that predict the likelihood of decision regret after OWHTO. METHOD: Questionnaires were administered to 98 eligible OWHTO recipients more than one year post-operatively. They answered "Yes" or "No" to the question "Would you go for the same choice (OWHTO) if you had to do it over again?" Univariate and multivariate logistic regression analyses were conducted using the decision regret questionnaire as the dependent variable against patient characteristics and surgery related factors. A receiver operating characteristic curve and area under the curve were constructed and calculated for age at surgery. Cut-off values were determined using the Youden principle and receiver operating characteristic curves. RESULTS: Among the 98 respondents, 18 (18%) reported regretting their decision. Older age at surgery was the only predictive risk factor for decision regret (P < 0.01). The area under the curve for the model using age to predict failure was 0.722. The cut-off value was 71 years. Patients aged 71 years or more had a 7.841 odds ratio for decision regret (P < 0.01). CONCLUSIONS: Older age emerged as a predictive risk factor for decision regret after OWHTO. Patients aged 71 years or older had a higher decision regret rate after OWHTO than younger patients and should more carefully weigh the suitability of OWHTO against other options.