Factors Causing Unintended Sagittal and Axial Alignment Changes in High Tibial Osteotomy: Comparative 3-Dimensional Analysis of Simulation and Actual Surgery.

BACKGROUND: Unintended secondary changes in the posterior tibial slope (PTS) and tibial torsion angle (TTA) may occur after medial open-wedge high tibial osteotomy (MOWHTO). In surgical procedures using patient-specific instruments (PSIs), it is essential to reproduce the PTS and TTA that were planned in simulations. PURPOSE: To analyze the factors causing unintended sagittal and axial alignment changes after MOWHTO. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Overall, 63 patients (70 knees) who underwent MOWHTO using a PSI between June 2020 and June 2023 were retrospectively reviewed. Preoperative and postoperative computed tomography scans were 3-dimensionally reconstructed. Simulated osteotomy was performed so that the weightbearing line could pass through the target point. A PSI gapper was 3-dimensionally printed to fit the posteromedial corner of the osteotomy gap in the simulated HTO model. After MOWHTO using the PSI gapper, the actual postoperative model was compared with the preoperative or simulation model. This assessment included PTS, TTA, hinge axis, and osteotomy-related parameters. Cortical breakage around the lateral hinge was evaluated to assess stability. RESULTS: The mean PTS and TTA did not change in the simulation. However, significant changes were observed in the actual postoperative PTS and TTA (change, -2.4°± 2.2° and -3.9°± 4.7°, respectively). The PTS was reduced, while the TTA decreased with internal rotation of the distal fragment. The difference in the axial hinge axis angle (AHA) between the simulation and actual surgery was the factor most correlated with the difference in the PTS (r = 0.625; P < .001). In regression analysis, the difference in the AHA was the only factor associated with the difference in the PTS (ß = 0.558; P = .001), and there were no factors that showed any significant associations with the difference in the TTA. In subgroup analyses for the change in the TTA, the correction angle and anterior osteotomy angle were significantly higher in the more internal rotation group (P = .023 and P = .010, respectively). The TTA change was significantly higher in the unstable group with lateral cortical breakage (P = .018). The unstable group was more likely to show an internal rotation of ≥5° (odds ratio, 5.0; P = .007). CONCLUSION: The AHA was associated with a difference in the PTS between the simulation and actual surgery. The change in the TTA was caused by a combination of multiple factors, such as a large correction angle and anterior osteotomy angle, but mainly by instability of the lateral cortical hinge.

Implantation of hUCB-MSCs generates greater hyaline-type cartilage than microdrilling combined with high tibial osteotomy.

PURPOSE: To compare the outcomes of treating large cartilage defects in knee osteoarthritis using human allogeneic umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation or arthroscopic microdrilling as a supplementary cartilage regenerative procedure combined with high tibial osteotomy (HTO). METHODS: This 1-year prospective comparative study included 25 patients with large, near full-thickness cartilage defects (International Cartilage Repair Society grade ≥ IIIB) in the medial femoral condyles and varus malalignment. Defects were treated with hUCB-MSC implantation or arthroscopic microdrilling combined with HTO. The primary outcomes were pain visual analogue scale and International Knee Documentation Committee subjective scores at 12, 24 and 48 weeks. Secondary outcomes included arthroscopic, histological and magnetic resonance imaging assessments at 1 year. RESULTS: Fifteen and 10 patients were treated via hUCB-MSC implantation and microdrilling, respectively. Baseline demographics, limb alignment and clinical outcomes did not significantly differ between the groups. Cartilage defects and total restored areas were significantly larger in the hUCB-MSC group (7.2 ± 1.9 vs. 5.2 ± 2.1 cm2, p = 0.023; 4.5 ± 1.4 vs. 3.0 ± 1.6 cm2, p = 0.035). The proportion of moderate-to-strong positive type II collagen staining was significantly higher in the hUCB-MSC group compared to that in the microdrilled group (93.3% vs. 60%, respectively). Rigidity upon probing resembled that of normal cartilage tissue more in the hUCB-MSC group (86.7% vs. 50.0%, p = 0.075). Histological findings revealed a higher proportion of hyaline cartilage in the group with implanted hUCB-MSC (p = 0.041). CONCLUSION: hUCB-MSC implantation showed comparable clinical outcomes to those of microdrilling as supplementary cartilage procedures combined with HTO in the short term, despite the significantly larger cartilage defect in the hUCB-MSC group. The repaired cartilage after hUCB-MSC implantation showed greater hyaline-type cartilage with rigidity than that after microdrilling. LEVEL OF EVIDENCE: Level II, Prospective Comparative Cohort Study.

Effects of concurrent cartilage procedures on cartilage regeneration in high tibial osteotomy: a systematic review.

PURPOSE: This systematic review aimed to evaluate the effects of concurrent cartilage procedures on cartilage regeneration when performed alongside high tibial osteotomy (HTO). MATERIALS AND METHODS: The systematic review followed the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). A comprehensive search was conducted on databases including PubMed, Embase, Cochrane Library, and Google Scholar, covering articles published until August 31, 2023. RESULTS: Sixteen studies (1277 patients) revealed that HTO, with or without concurrent cartilage procedures, leads to cartilage regeneration based on the International Cartilage Repair Society (ICRS) grade during second-look arthroscopy. No concurrent procedure showed improvement in ICRS grade (mean difference: - 0.80 to - 0.49). Microfracture (mean difference: - 0.75 to - 0.22), bone marrow aspirate concentrate (BMAC) (mean difference: - 1.37 to - 0.67), and human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) (mean difference: - 2.46 to - 1.81) procedures also demonstrated positive outcomes. Clinical outcome assessments for each cartilage procedure were also improved during postoperative follow-up, and no specific complications were reported. CONCLUSIONS: HTO with or without concurrent cartilage procedures promotes cartilage regeneration observed during second-look arthroscopy, with improved clinical outcomes. Future randomized controlled trials on the same topic, along with subsequent meta-analyses, are necessary for conclusive findings.

Small Intercondylar Notch Size Is Not Associated with Poor Surgical Outcomes of Anatomical Single-Bundle Anterior Cruciate Ligament Reconstructions.

Background: Although many studies have been conducted on the association between the intercondylar notch size and the risk of anterior cruciate ligament (ACL) injury, few studies have examined its relationship with the condition after surgical treatment. Therefore, this study aimed to investigate the surgical outcomes of anatomical single-bundle ACL reconstruction according to intercondylar notch volumes. Methods: Medical records of patients who underwent anatomical single-bundle ACL reconstruction using a tibialis anterior allograft between 2015 and 2019 were retrospectively reviewed. For each sex, eligible patients were classified into two groups based on their percentile of intercondylar notch volumes, which were measured using postoperative three-dimensional computed tomography images (group S, ≤ 50th percentile of included patients; group L, > 50th percentile of included patients). Additional grouping was performed based on the group's percentiles of normalized values of intercondylar notch volumes to body heights. Between-group comparative analyses were performed on the perioperative data and surgical outcomes in both objective and subjective aspects. Results: One hundred patients were included in the study. For male patients, there were no differences in the overall surgical outcomes between groups, whereas group L showed a significantly greater knee anteroposterior (AP) laxity than group S at the final follow-up (p = 0.042 for the side-to-side differences [SSD] at the maximum manual force). Similarly, there were no differences in the female patients in the overall surgical results between the groups, whereas group L showed a significantly greater knee AP laxity at the final follow-up (p = 0.020 for the SSD at 134 N; p = 0.011 for the SSD at the maximum manual force). Additional analyses based on the normalized values of the intercondylar notch volume showed consistent results for male patients, and additional grouping for female patients was identical to the existing grouping. Conclusions: The surgical outcomes of anatomical single-bundle ACL reconstruction in patients with relatively small intercondylar notch volumes were comparable to those with large notch volumes, but rather showed favorable outcomes in postoperative knee AP laxity.

Allogeneic umbilical cord blood-derived mesenchymal stem cell implantation versus microdrilling combined with high tibial osteotomy for cartilage regeneration.

This study compared cartilage regeneration outcomes in knee osteoarthritis (OA) using allogeneic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation and microdrilling with high tibial osteotomy (HTO). Fifty-four patients (60 knees) were included: 24 (27 knees) in the hUCB-MSC group and 30 (33 knees) in the microdrilling group. Both groups showed significant improvements in pain and functional scores at 6, 12, and 24 months compared to baseline. At 24 months, the hUCB-MSC group had significantly improved scores. Arthroscopic assessment at 12 months revealed better cartilage healing in the hUCB-MSC group. In subgroup analysis according to the defect site, hUCB-MSC implantation showed superior cartilage healing for anterior lesions. In conclusion, both treatments demonstrated effectiveness for medial OA. However, hUCB-MSC implantation had better patient-reported outcomes and cartilage regeneration than microdrilling. The study suggests promising approaches for cartilage restoration in large knee defects due to OA.

Prognostic Factors for Clinical Outcome and Cartilage Regeneration after Implantation of Allogeneic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Large-Sized Cartilage Defects with Osteoarthritis.

OBJECTIVE: To analyze the prognostic factors for clinical outcomes and cartilage regeneration after the implantation of allogeneic human umbilical cord blood mesenchymal stem cell (hUCB-MSC) for treating large-sized cartilage defects with osteoarthritis. DESIGN: This study is a case-series with multiple subgroup analyses that divides the included patients into multiple subgroups based on various factors. Overall, 47 patients who underwent hUCB-MSC implantation were included. The patient-reported outcomes, magnetic resonance imaging (MRI), and second-look arthroscopy were used to assess the outcomes. RESULTS: Combined realignment surgery significantly correlated with clinical outcomes, particularly pain. No other factors significantly influenced the clinical outcomes in short-term period. Subgroups with large defect sizes or meniscal insufficiency showed significantly poor MRI and arthroscopy outcomes (MRI, P = 0.001, P = 0.001; arthroscopy, P = 0.032, P = 0.042). The logistic regression showed that patients with a 1 cm2 larger defect size were 1.91 times less likely to achieve favorable MRI outcomes (P = 0.017; odds ratio [OR], 1.91). Cut-off value to predict the poor outcome was >5.7 cm2 (area under the curve, 0.756). A cartilage defect size >5.7 cm2 was the major poor prognostic factor for cartilage regeneration on MRI (P = 0.010; OR, 17.46). If the postoperative alignment shifted by 1° opposite to the cartilage defect, it was 1.4 times more likely to achieve favorable MRI outcomes (P = 0.028; OR, 1.4). CONCLUSION: Combining realignment surgery showed a better prognosis for pain improvement. Cartilage defect size, meniscal function, and postoperative alignment are significant prognostic factors for cartilage regeneration. A cartilage defect size >5.7 cm2 was significantly related to poor cartilage regeneration.

Release or transection of superficial medial collateral ligament during open-wedge high tibial osteotomy demonstrated similar clinical outcomes and valgus laxity.

PURPOSE: To analyse whether valgus laxity and clinical outcomes differ depending on whether the superficial medial collateral ligament (sMCL) is released or transected during medial open-wedge high tibial osteotomy (MOWHTO). METHODS: Consecutive patients who underwent MOWHTO and subsequent radiological follow-up for at least 2 years were retrospectively evaluated. The patients were divided into release and transection groups, according to the sMCL manipulation technique. Each patient was assessed for the following variables on valgus stress radiographs taken before surgery and at the 12- and 24-month follow-ups: the absolute value of valgus (ABV) and side-to-side difference (SSD) between the affected and normal sides. The differences between preoperative SSD and those at 12 and 24 months were respectively calculated and defined as delta SSD (ΔSSD). The Visual Analogue Scale, Lysholm knee, International Knee Documentation Committee subjective, and Knee Injury and Osteoarthritis Outcome scores were used to evaluate patient-reported outcomes. RESULTS: Eighty-five patients were included in the study. Forty-two patients (49.6%) underwent sMCL release, and the remaining 43 patients (50.4%) underwent sMCL transection. No significant differences were observed in the ABV and SSD of valgus laxity at the different time points between the two groups (n.s.). Furthermore, no significant differences were observed in the ΔSSD at the 12- and 24-month follow-ups between the two groups (n.s.). Significant improvement from preoperative values was observed in all patient-reported outcomes (p < 0.001), with no significant differences between the two groups at any time point (n.s.). CONCLUSION: Significant improvements in clinical outcomes were observed, regardless of the technique used. Postoperative valgus laxity did not occur with either technique. The transection technique, which can be performed more simply and quickly, demonstrated similar clinical outcomes and valgus laxity to the release technique. LEVEL OF EVIDENCE: Level III.

Preoperative joint line obliquity, a newly identified factor for overcorrection, can be incorporated into a novel preoperative planning method to optimise alignment in high tibial osteotomy.

PURPOSE: The aim of this study was to analyse the factors associated with additional postoperative alignment changes after accurate bony correction by selecting only patients with well-performed bony correction as planned and develop a method of incorporating significant factors into preoperative planning. METHODS: Among 104 consecutive patients who underwent medial open wedge high tibial osteotomy (MOWHTO) between October 2019 and July 2022, 61 with well-performed bony corrections were retrospectively reviewed. The major criterion for well-performed bony correction was a difference of <1° between the simulated medial proximal tibial angle (MPTA) and the actual postoperative MPTA as measured in three dimensions. Radiographic parameters, such as the joint line convergence angle (JLCA) and joint line obliquity (JLO), were measured preoperatively and postoperatively, utilising standing and supine whole lower extremity anteroposterior, valgus and varus stress radiographs. Multiple linear regression analysis identified the factors affecting alignment changes, and a prediction model was developed. A method for applying this prediction model to preoperative planning was proposed. RESULTS: Preoperative JLCA on standing (preJLCAstd ), preoperative JLCA on 0° valgus stress radiograph (vgJLCA0 ), and preoperative JLO (preJLO) were significantly correlated with JLCA change (∆JLCA) (p < 0.001, p < 0.001, p = 0.006). The prediction model was estimated as ∆JLCA = 0.493 × (vgJLCA0 ) - 0.727 × (preJLCAstd ) + 0.189 × (preJLO) - 1.587 in. (R = 0.815, modified R2 = 0.646, p < 0.001). The proposed method resulted in a reduced overcorrection rate (p = 0.003) and an improved proportion of acceptable alignments (p = 0.013). CONCLUSION: PreJLCAstd , vgJLCA0  and preJLO can be used to estimate ∆JLCA. PreJLO was recently identified as a significant factor associated with additional alignment changes. Utilising the proposed preoperative planning and a prediction model with these factors shows promise in calibrating postoperative alignment after MOWHTO. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Marrow stimulation procedures for high-grade cartilage lesions during surgical repair of medial meniscus root tear yielded suboptimal outcomes, whilst small lesions showed surgical eligibility.

PURPOSE: To investigate the surgical outcomes of arthroscopic pull-out repair for medial meniscus root tear (MMRT) combined with the marrow stimulation procedures (MSP) for accompanying high-grade cartilage lesions. METHODS: Patients who underwent arthroscopic pull-out repair for MMRT between 2010 and 2019 were retrospectively reviewed. Patients who had at least 3 years of follow-up were included and classified into two groups according to whether MSP (microfracture or microdrilling) were performed on cartilage lesions in the medial tibiofemoral joint (group 1, patients with International Cartilage Repair Society [ICRS] grade 0-3a lesions and did not undergo MSP; group 2, patients with ICRS grade 3b-3d lesions and underwent MSP). Comparative analyses, including non-inferiority trials, were conducted between groups for subjective and objective outcomes. In addition, group 2 was further divided into two subgroups according to cartilage lesion size and compared with group 1 (group S, ≤ 2.0 cm2; group L, > 2.0 cm2). RESULTS: A total of 94 patients were included (group 1, 68 patients; group 2, 26 patients). There were no significant differences in clinical scores at postoperative 3 years and final follow-up between groups 1 and 2, but group 2 failed to satisfy the non-inferiority criteria compared to group 1 overall. In objective outcomes, group 2 did not meet the non-inferiority criteria for the rate of osteoarthritis progression compared to group 1, and it also showed a significantly higher proportion of high-grade osteoarthritis at final follow-up (P = 0.044) and a higher degree of osteoarthritis progression than group 1 (P = 0.03 for pre- to postoperative 3 years, and P = 0.006 for pre- to final follow-up). In additional evaluations comparing the subgroups of group 2 and group 1, group S showed relatively favourable results compared to group L in objective outcomes at final follow-up. CONCLUSION: Patients who underwent arthroscopic pull-out repair for MMRT combined with MSP for accompanying high-grade cartilage lesions showed suboptimal outcomes compared to those with no or low-grade lesions at mid-term follow-up. High-grade cartilage lesions ≤ 2.0 cm2 may be candidates for the surgical repair of MMRT if MSP are performed, but those with larger lesions may require alternative treatment strategies. LEVEL OF EVIDENCE: III.

Factors Influencing the Initial Constraint Level of the Knee Joint and Its Effect on Clinical Outcomes After ACL Reconstruction With Hamstring Graft.

Background: A force-based tension protocol that uses a certain amount of tension at graft fixation could still give rise to variations in initial constraint levels of the knee joint in terms of side-to-side difference (SSD) in anterior translation. Purpose: To investigate the factors influencing the initial constraint level in anterior cruciate ligament (ACL)-reconstructed knees and compare outcomes according to the level of constraint in terms of anterior translation SSD. Study Design: Cohort study; Level of evidence, 3. Methods: Included were 113 patients who underwent ipsilateral ACL reconstruction using an autologous hamstring graft and had minimum 2-year follow-up outcomes. All grafts were tensioned and fixed at 80 N using a tensioner at the time of graft fixation. The patients were classified into the following 2 groups according to the initial anterior translation SSD, measured using the KT-2000 arthrometer: a physiologic constraint group with restored anterior laxity ≤2 mm (group P; n = 66) and a high-constraint group with restored anterior laxity >2 mm (group H; n = 47). Clinical outcomes were compared between the groups, and preoperative and intraoperative variables were evaluated to identify factors affecting the initial constraint level. Results: Between group P and group H, generalized joint laxity (P = .005), posterior tibial slope (P = .022), and anterior translation measured in the contralateral knee (P < .001) were found to differ significantly. Measured anterior translation in the contralateral knee was the only significant predictor of high initial graft tension (P = .001). No significant differences were found between the groups regarding clinical outcomes and subsequent surgery. Conclusion: Greater anterior translation measured in the contralateral knee was an independent predictor of a more constrained knee after ACL reconstruction. The short-term clinical outcomes after ACL reconstruction were comparable, regardless of the initial constraint level in terms of anterior translation SSD.

Outpatient-based diagnostic criteria for partial ACL injury: clinical outcomes of non-operative treatment and radiographic predictor.

INTRODUCTION: This study aimed to (1) evaluate the short-term clinical outcomes of patients who underwent non-operative treatment for partial anterior cruciate ligament (ACL) tears diagnosed using the outpatient-based diagnostic criteria and (2) investigate the radiographic predictors distinguishing patients at risk of non-operative treatment failure. METHODS: From 2010 to 2019, patients diagnosed with partial ACL tears and treated with non-operative treatment were reviewed retrospectively. Patients were then classified into two groups: those who successfully responded to non-operative treatment (group S) and those who failed to respond to non-operative treatment and required surgical reconstruction within 6 months after injury (group F). ACL laxity, patient-reported outcomes (PROs), and several radiographic parameters were analyzed. To identify radiographic predictors related to clinical outcomes, radiographic parameters were compared between the groups, which were statistically matched for potential confounders (age and activity level) using inverse probability of treatment weighting. RESULTS: A total of 44 patients were analyzed (mean age, 28.7 ± 8.7 years; 31 men), and classified into two groups (group S, 23 patients; group F, 21 patients). There were no significant differences in ACL laxity and PROs between the groups at 1 year after either non-operative treatment or surgical reconstruction. A comparison of radiographic parameters between the groups revealed significant differences in several parameters related to secondary signs of ACL injury. Subsequent regression analyses revealed that anterior tibial translation and extent of bone bruises were radiographic predictors related to clinical outcomes. CONCLUSION: Non-operative treatment for partial ACL tears diagnosed using the outpatient-based diagnostic criteria can provide successful short-term clinical outcomes in selective patients. Secondary signs of ACL injuries, particularly the amount of anterior tibial translation and the extent of bone bruises, are radiographic predictors that could differentiate patients at risk of non-operative treatment failure. LEVEL OF EVIDENCE: Retrospective cohort study, III.

The orientation of the ALL femoral tunnel to minimize collision with the ACL tunnel depends on the need or not of far-cortex drilling.

PURPOSE: To (1) evaluate the optimal drill orientation of the anterolateral ligament (ALL) femoral tunnel to minimize collision with the anterior cruciate ligament (ACL) femoral tunnel during anatomical ACL reconstruction according to the need for far-cortex drilling and (2) investigate the geometric factors that affect tunnel collision secondary to drill orientation of the ALL femoral tunnel. METHODS: A three-dimensional femoral model of patients who underwent anatomical single-bundle ACL reconstruction between 2015 and 2016 was constructed, and the geometric factors were evaluated. Virtual ALL femoral tunnels were created to simulate 45 drilling conditions. For each condition, whether the virtual ALL femoral tunnel and its trajectory violated the femoral cortex and the minimum distance between tunnels was investigated. RESULTS: Thirty-nine subjects were included. Overall violation rates of the femoral cortex by the ALL tunnels and its trajectories were 11.1% (195 of 1755 conditions) and 40.7% (714 of 1755 conditions), respectively. A drilling angle of axial 0° and coronal - 40° showed the longest minimum distance between tunnels without femoral cortex violation by the ALL tunnel (6.3 ± 4.0 mm; collision rate 2.6% [1 of 39 subjects]). With simultaneous consideration of the ALL tunnel's trajectory representing far-cortex drilling, a drill angle of axial 40° and coronal 10° showed the longest minimum distance between tunnels without femoral cortex violation (0.6 ± 3.9 mm; collision rate 38.5% [15 of 39 subjects]). For surgical techniques requiring far-cortex drilling, regression analyses were performed on geometric factors that could affect tunnel collision, which revealed that the sagittal inclination angle of the ACL and the distance between the ACL femoral tunnel's outlet and ALL's femoral attachment were associated with tunnel collision. CONCLUSION: The optimal drill orientations of the ALL femoral tunnel to minimize collision with the ACL femoral tunnel were axial 0° and coronal - 40° for surgical techniques not requiring far-cortex drilling and axial 40° and coronal 10° for techniques requiring far-cortex drilling. For techniques requiring far-cortex drilling, additional adjustment for orientation of the ACL femoral tunnel is required to reduce the risk of tunnel collision. Therefore, an individualized surgical strategy should be applied according to the graft fixation method of the ALL femoral tunnel.

Graft isometry during anatomical ACL reconstruction has little effect on surgical outcomes.

PURPOSE: To investigate the surgical outcomes of anatomical anterior cruciate ligament (ACL) reconstruction according to the graft isometry measured during surgery. METHODS: Electrical medical records of patients who underwent an arthroscopic ACL reconstruction through the transportal technique using hamstring tendon autograft between 2012 and 2016 were retrospectively reviewed. The patients were classified into two groups based on the graft length change throughout the knee range of motion measured just before graft fixation (Group 1, graft length change ≤ 2 mm; Group 2, graft length change > 2 mm). Comparative analyses, including a non-inferiority trial, were performed regarding the clinical scores, knee laxity, and radiographic parameters between the groups. RESULTS: A total of 67 patients were included in the study. The total change in the length of ACL graft throughout the knee range of motion was 1.4 ± 0.4 mm in Group 1 (range, 0.2-2.0 mm), and 3.0 ± 0.7 mm in Group 2 (range, 2.2-5.0 mm). Group 1 showed a relatively high (proximal) femoral tunnel and shallow (anterior) tibial tunnel compared to Group 2 (P < 0.001 and P = 0.028, respectively), but there were no apparent differences in the macroscopic view. There were no statistically significant differences in the clinical outcomes between groups at 2 years after surgery, which satisfied the non-inferiority criterion of Group 1 in terms of clinical scores and knee laxity compared to Group 2. CONCLUSION: The surgical outcomes of anatomical ACL reconstruction in patients with non-isometric ACL graft were not inferior in terms of clinical scores and knee laxity, compared to those with nearly-isometric ACL graft. The graft tunnel placement in the isometric position during anatomical ACL reconstruction, which is technically challenging in the clinical setting, is not a crucial factor in terms of clinical outcomes. LEVEL OF EVIDENCE: Level IV.

Effect of the Osteotomy Inclination Angle in the Sagittal Plane on the Posterior Tibial Slope of the Tibiofemoral Joint in Medial Open-Wedge High Tibial Osteotomy: Three-Dimensional Computed Tomography Analysis.

The posterior tibial slope of the tibiofemoral joint changes after medial open wedge high tibial osteotomy (MOWHTO), but little is known about the effect of the sagittal osteotomy inclination angle on the change in the posterior tibial slope of the tibiofemoral joint. The purpose of this study was to investigate the effect of the osteotomy inclination angle in the sagittal plane on changes in the posterior tibial slope after MOWHTO by comparing how anterior and posterior inclination affect the posterior tibial slope of the tibiofemoral joint. The correlation between the osteotomy inclination angle and the postoperative posterior tibial slope angle was also assessed. Between May 2011 and November 2017, 80 patients with medial compartment osteoarthritis who underwent MOWHTO were included. The patients were divided into two groups according to the sagittal osteotomy inclination angle on the 3D reconstructed model. Patients with an osteotomy line inclined anteriorly to the medial tibial plateau line were classified into group A (58 patients). Patients with posteriorly inclined osteotomy line were classified as group P (22 patients). In the 3D reconstructed model, the preoperative and postoperative posterior tibial slope, osteotomy inclination angle relative to medial tibial plateau line in sagittal plane, and gap distance and ratio of the anterior and posterior osteotomy openings were measured. The preoperative and postoperative hip-knee-ankle angle, weight-bearing line ratio, and posterior tibial slope were also measured using plain radiographs. In the 3D reconstructed model, the postoperative posterior tibial slope significantly increased in group A (preoperative value = 9.7 ± 2.9°, postoperative value = 10.7 ± 3.0°, p < 0.001) and decreased in group P (preoperative value = 8.7 ± 2.7°, postoperative value = 7.7 ± 2.7°, p < 0.001). The postoperative posterior tibial slope (group A = 10.7 ± 3.0°, group P = 7.7 ± 2.7°, p < 0.001) and posterior tibial slope change before and after surgery (group A = 1.0 ± 0.8°, group P = -0.9 ± 0.8°, p < 0.001) also differed significantly between the groups. The Pearson correlation coefficient was 0.875 (p < 0.001) for the osteotomy inclination angle, and multivariate regression analysis showed that the only significant factor among the variables was the sagittal osteotomy inclination angle (ß coefficient = 0.216, p < 0.001). The posterior tibial slope changed according to the osteotomy inclination angle in the sagittal plane after MOWHTO. The postoperative posterior tibial slope tended to increase when the osteotomy line was inclined anteriorly with respect to the medial tibial plateau line but decreased when the osteotomy line was inclined posteriorly. To avoid inadvertent change of posterior tibial slope, close attention needs to be paid to maintaining the sagittal osteotomy line parallel to the medial joint line during MOWHTO.

Incidence and risk factors analysis for mortality after total knee arthroplasty based on a large national database in Korea.

This study aimed to analyze the rates and risk factors of postoperative mortality among 560,954 patients who underwent total knee arthroplasty (TKA) in Korea. The National Health Insurance Service-Health Screening database was used to analyze 560,954 patients who underwent TKA between 2005 and 2018. In-hospital, ninety-day, and one-year postoperative mortality, and their association with patient's demographic factors and various comorbidities (ie., cerebrovascular disease, congestive heart failure, and myocardial infarction) were assessed. In-hospital, ninety-day and one-year mortality rates after TKA were similar from 2005 to 2018. The risk of in-hospital mortality increased with comorbidities like cerebrovascular disease (hazard ratio [HR] = 1.401; 95% confidence interval [CI] = 1.064-1.844), congestive heart failure (HR = 2.004; 95% CI = 1.394 to 2.881), myocardial infarction (HR = 2.111; 95% CI = 1.115 to 3.998), and renal disease (HR = 2.641; 95% CI = 1.348-5.173). These co-morbidities were also independent predictors of ninety-day and one-year mortality. Male sex and old age were independent predictors for ninety-day and one-year mortality. And malignancy was risk factor for one-year mortality. The common preoperative risk factors for mortality in all periods were male sex, old age, cerebrovascular disease, congestive heart failure, myocardial infarction, and renal disease. Malignancy was identified as risk factor for one-year mortality. Patients with these comorbidities should be provided better perioperative care.

The Graft Insertion Length in the Femoral Tunnel During Anterior Cruciate Ligament Reconstruction With Suspensory Fixation and Tibialis Anterior Allograft Does Not Affect Surgical Outcomes but Is Negatively Correlated With Tunnel Widening.

PURPOSE: To investigate the surgical outcomes of anterior cruciate ligament (ACL) reconstruction using a low-dose irradiated tibialis anterior allograft with a fixed-loop cortical suspension device for the femur based on the graft insertion length (GIL) in the femoral tunnel. METHODS: Between January 2010 and January 2018, the medical records of consecutive patients who underwent arthroscopic ACL reconstruction with a tibialis anterior allograft fixed with the EndoButton CL for the femur and who had at least 2 years of follow-up were retrospectively evaluated. Patients were classified into 3 groups based on the GIL in the femoral tunnel (group 1, GIL < 15 mm; group 2, GIL of 15-20 mm; and group 3, GIL > 20 mm), and their functional scores, knee laxity, and radiographic parameters were evaluated. RESULTS: A total of 91 patients were analyzed. There were no statistically significant differences in the functional scores and knee laxity between the 3 groups at 2 years postoperatively. However, significant differences were observed in tunnel widening at 1 year postoperatively in the femur (P = .045 for absolute value and P = .004 for relative value) and the tibia (P = .014 for absolute value and P = .012 for relative value), revealing that both the femoral and tibial tunnels widened as the GIL decreased. Additional linear regression analyses were performed to identify whether the GIL independently affects tunnel widening. Consequently, the femoral tunnel depth, tunnel diameter, and GIL were found to independently influence femoral tunnel widening (P = .008, P = .019, and P < .001, respectively), whereas the tunnel diameter and GIL affected tibial tunnel widening (P < .001 and P = .004, respectively). CONCLUSIONS: The GIL in the femoral tunnel during ACL reconstruction using a tibialis anterior allograft with a fixed-loop cortical suspension device for the femur has no significant association with the postoperative functional outcomes and knee laxity, but it has a negative correlation with tunnel widening in the femur and the tibia. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Mild to Moderate Varus Alignment in Relation to Surgical Repair of a Medial Meniscus Root Tear: A Matched-Cohort Controlled Study With 2 Years of Follow-up.

BACKGROUND: Increased varus alignment of the lower extremity is known to be a poor prognostic factor for the surgical repair for a medial meniscus root tear (MMRT). However, given the concept of constitutional varus, which is present in a substantial portion of the normal population, the generally accepted surgical indication for MMRT concerning a varus alignment of 5° may be unnecessarily narrow. PURPOSE: To compare the surgical outcomes of arthroscopic transtibial pullout repair of MMRT according to the degree of varus alignment of the lower extremity. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients who underwent isolated arthroscopic transtibial pullout repair of MMRT between January 2010 and July 2017 at one institution and had a minimum follow-up of 2 years were included in this study. Patients were classified into 1 of 2 groups: the experimental group (n = 22) included patients with a preoperative hip-knee-ankle angle between 5° and 10° varus (mild to moderate varus alignment) and the control group (n = 51) included those with a preoperative hip-knee-ankle angle <5° varus (neutral alignment). Clinical scores and radiographic parameters were compared between the groups to assess surgical outcomes, which were statistically matched for potential confounders (age, body mass index, the severity of cartilage lesion) by use of the inverse probability of treatment weighting. A noninferiority trial was performed comparing the experimental and control groups in terms of subjective outcomes (International Knee Documentation Committee subjective and Lysholm scores) and objective outcomes (postoperative medial meniscal extrusion and the rate of osteoarthritis progression). RESULTS: There were no statistically significant differences in surgical outcomes between the groups in subjective and objective aspects, which were consistent before and after inverse probability of treatment weighting. Apart from the clinical improvement observed in both groups, overall degenerative changes in the knee were found, although progression rates did not differ between the groups. In terms of the noninferiority trial, the overall surgical outcomes in the experimental group were not inferior to those in the control group. CONCLUSION: The short-term surgical outcomes of arthroscopic transtibial pullout repair for MMRT of patients with mild to moderate varus alignment were not inferior to but rather comparable with those with neutral alignment in terms of subjective and objective aspects. Therefore, it would be inappropriate to exclude patients with a diagnosis of MMRT from being indicated for the surgery simply because of mild to moderate varus alignment.

Allogeneic Umbilical Cord Blood-Derived Mesenchymal Stem Cell Implantation Versus Microfracture for Large, Full-Thickness Cartilage Defects in Older Patients: A Multicenter Randomized Clinical Trial and Extended 5-Year Clinical Follow-up.

BACKGROUND: There is currently no optimal method for cartilage restoration in large, full-thickness cartilage defects in older patients. PURPOSE: To determine whether implantation of a composite of allogeneic umbilical cord blood-derived mesenchymal stem cells and 4% hyaluronate (UCB-MSC-HA) will result in reliable cartilage restoration in patients with large, full-thickness cartilage defects and whether any clinical improvements can be maintained up to 5 years postoperatively. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A randomized controlled phase 3 clinical trial was conducted for 48 weeks, and the participants then underwent extended 5-year observational follow-up. Enrolled were patients with large, full-thickness cartilage defects (International Cartilage Repair Society [ICRS] grade 4) in a single compartment of the knee joint, as confirmed by arthroscopy. The defect was treated either with UCB-MSC-HA implantation through mini-arthrotomy or with microfracture. The primary outcome was proportion of participants who improved by ≥1 grade on the ICRS Macroscopic Cartilage Repair Assessment (blinded evaluation) at 48-week arthroscopy. Secondary outcomes included histologic assessment; changes in pain visual analog scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and International Knee Documentation Committee (IKDC) score from baseline; and adverse events. RESULTS: Among 114 randomized participants (mean age, 55.9 years; 67% female; body mass index, 26.2 kg/m2), 89 completed the phase 3 clinical trial and 73 were enrolled in the 5-year follow-up study. The mean defect size was 4.9 cm2 in the UCB-MSC-HA group and 4.0 cm2 in the microfracture group (P = .051). At 48 weeks, improvement by ≥1 ICRS grade was seen in 97.7% of the UCB-MSC-HA group versus 71.7% of the microfracture group (P = .001); the overall histologic assessment score was also superior in the UCB-MSC-HA group (P = .036). Improvement in VAS pain, WOMAC, and IKDC scores were not significantly different between the groups at 48 weeks, however the clinical results were significantly better in the UCB-MSC-HA group at 3- to 5-year follow-up (P < .05). There were no differences between the groups in adverse events. CONCLUSION: In older patients with symptomatic, large, full-thickness cartilage defects with or without osteoarthritis, UCB-MSC-HA implantation resulted in improved cartilage grade at second-look arthroscopy and provided more improvement in pain and function up to 5 years compared with microfracture. REGISTRATION: NCT01041001, NCT01626677 (ClinicalTrials.gov identifier).

Costal Chondrocyte-Derived Pellet-Type Autologous Chondrocyte Implantation versus Microfracture for Repair of Articular Cartilage Defects: A Prospective Randomized Trial.

OBJECTIVE: To compare the efficacy and safety of costal chondrocyte-derived pellet-type autologous chondrocyte implantation (CCP-ACI) with microfracture (MFx) for repair of articular cartilage defects of the knee. DESIGN: Thirty subjects with an International Cartilage Repair Society (ICRS) grade 3 to 4 chondral defect (2-10 cm2 in area; ≤4 cm3 in volume) were randomized at a ratio of 2:1 (CCP-ACI:MFx). Twenty patients were allocated in the CCP-ACI group and 10 patients in the MFx group. CCP-ACI was performed by harvesting costal cartilage at least 4 weeks before surgery. Implantation was performed without any marrow stimulation. Efficacy and safety were assessed at weeks 8, 24, and 48 after surgery according to the magnetic resonance observation of cartilage repair tissue (MOCART) score and clinical outcomes. RESULTS: MOCART scores improved from baseline to 24 and 48 weeks postoperatively in both treatment groups. The improvement in MOCART scores in the CCP-ACI group was significantly greater than that in the MFx group at 24 and 48 weeks (39.1 vs 21.8 and 43.0 vs 24.8, respectively). The proportions of complete defect repair and complete integration were significantly higher in the CCP-ACI group than the MFx group at 48 weeks. Improvement in Lysholm score and KOOS subscores, including Function (Sports and Recreational Activity) and knee-related quality of life was significantly greater in the CCP-ACI group than the MFx group at 48 weeks (35.4 vs 31.5, 35.7 vs 28.5, and 27.9 vs 11.6, respectively). CONCLUSION: Treatment of cartilage defects with CCP-ACI yielded satisfactory cartilage tissue repair outcomes, with good structural integration with native cartilage tissue shown by magnetic resonance imaging at 24 and 48 weeks after surgery. LEVEL OF EVIDENCE: Level 1: Randomized controlled study.

Radiographic Prognostic Factors Relevant to Surgical Outcomes of Arthroscopic Partial Medial Meniscectomy in Elderly Patients with Mild Osteoarthritis.

The aim of this study was to investigate radiographic factors relevant to predict surgical outcomes of arthroscopic partial meniscectomy (APM) in elderly patients with mild osteoarthritis (Kellgren-Lawrence grades 1 and 2). Data of 172 consecutive patients aged >70 years who underwent arthroscopic meniscal surgery were reviewed retrospectively. The patients who met the inclusion criteria were classified into two groups based on the minimal clinically important difference value of the Lysholm knee scoring scale comparing the score of the last visit with that of the preoperative period: group 1 (with clinically significant improvement) and group 2 (without clinically important change). Radiographic factors assessed on X-ray and magnetic resonance images were evaluated using bivariate and logistic regression analyses. A total of 73 patients were included in this study. Bivariate analysis revealed that the extent of meniscus extrusion (p = 0.031), meniscus extrusion ratio (p = 0.001), and grade of meniscus degeneration (p = 0.019) were significantly different between the groups. Multivariate logistic regression analysis showed that the meniscus extrusion ratio was the most important independent predictive factor for surgical outcomes with clinically important changes (coefficient = 0.159, p = 0.009). On receiver operating characteristic (ROC) curve analysis, the cutoff point of the meniscus extrusion ratio discriminating the two groups was 34.2% (sensitivity: 79.3%; specificity: 68.6%; accuracy: 72.6%). Meniscus extrusion ratio was the most relevant predictive factor for discriminating patients with clinically important change. Meniscus extrusion ratio, with the cutoff point of 34.2%, could serve as a guide to determine whether to perform APM in elderly patients with mild osteoarthritis. This is a Level IV, therapeutic case series study.