Postoperative Decrease in Bone Marrow Lesion Associated With Better Clinical Outcomes Following Medial Open-Wedge High Tibial Osteotomy.

PURPOSE: To assess serial changes of preoperative bone marrow lesion (BML) following medial open-wedge high tibial osteotomy (MOWHTO) up to 2 years and evaluate whether postoperative change of BML affected patient-reported outcome measures (PROMs) at 2 years' follow-up. Factors related to the postoperative changes in BML also were evaluated. METHODS: The current study retrospectively assessed prospectively collected data of consecutive patients between December 2016 and March 2018 who underwent MOWHTO for symptomatic knee osteoarthritis with varus malalignment (≥5°) and a minimum 2-year follow-up. Serial magnetic resonance imaging scans at preoperative and postoperative 3, 6, 18, and 24 months were performed, and the extent of BML was evaluated consecutively using 2 validated methods. Clinically, preoperative and postoperative PROMs and their achievement of minimal clinically important difference values were evaluated. The associations of the extent of BMLs with PROMs at each follow-up period over time were analyzed using a linear mixed model. Furthermore, factors related to the postoperative changes of BML were assessed. RESULTS: Of 26 patients, 21 (80.8%) had preoperative BML at medial femoral and tibial condyles. The postoperative decrease in BML was noted in 17 (81.0%) and 18 (85.7%) at medial femoral and tibial condyles. The BML decreased at postoperative 3 months and, thereafter, the extent of BML gradually reduced until postoperative 24 months. The proportion of patients achieved minimal clinically important difference was 84.6% for total Western Ontario and McMaster Universities Osteoarthritis Index scores and 80.8%, 76.9%, and 84.6% for KOOS symptom, pain, and activity of daily living subscales. Postoperative decrease in BML was significantly associated with better PROMs over postoperative 24 months. Furthermore, normo-correction (2°-5° valgus) was a significant factor for decreased BML following MOWHTO. CONCLUSIONS: Preoperative BML gradually decreased with time following MOWHTO, and the postoperative decrease in BML related with better PROMs over postoperative 24 months. Moreover, postoperative valgus alignment was a significant factor relating the postoperative decrease of BML. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Closed-wedge high tibial osteotomy is more advantageous to maintain the correction than open-wedge high tibial osteotomy in osteopenic patients.

PURPOSE: To compare the incidence of correction loss and survival rate between closed-wedge and open-wedge high tibial osteotomies (CWHTO and OWHTO, respectively) in patients with osteopenic and normal bone. METHODS: Retrospective review was conducted for 115 CWHTOs and 119 OWHTOs performed in osteopenic patients [- 2.5 < Bone mineral density (BMD) T scores ≤ - 1] and 136 CWHTOs and 138 OWHTOs performed in normal patients (BMD T score > - 1) from 2012 to 2019. Demographics were not different between CW- and OWHTOs in osteopenic and normal patients (n.s., respectively). Radiographically, the mechanical axis (MA), medial proximal tibial angle (MPTA), and posterior tibial slope (PTS) were evaluated pre- and postoperatively (2 weeks after HTO). The occurrence of hinge fractures was investigated using radiographs taken on the operation day. The correction change was calculated as the last follow-up value minus postoperative MPTA. Correction loss was defined when the correction change was ≥ 3°. The survival rate (failure: correction loss) was investigated. RESULTS: There were no significant differences in the pre and postoperative MA, MPTA, PTS, and value changes between CW- and OWHTOs in osteopenic and normal patients (n.s., respectively); the incidence of unstable hinge fractures also did not differ significantly (CWHTO vs. OWHTO = 7 vs. 7.6% in osteopenic patients; 2.9 vs. 3.6% in normal patients; n.s., respectively). The average correction change (CWHTO = - 0.6°, OWHTO = - 1.3°, p = 0.007), incidence of correction loss (CWHTO = 1.7%, OWHTO = 9.2%, p = 0.019), and 5-year survival rates (CWHTO = 98.3%, OWHTO = 90.8%, p = 0.013) differed significantly in osteopenic patients; there were no significant differences in these results in normal patients (n.s., respectively). CONCLUSION: CWHTO was more advantageous than OWHTO regarding the correction loss in osteopenic patients. Intra- and postoperative care that consider poor bone quality will be required when performing OWHTOs in osteopenic patients. LEVEL OF EVIDENCE: III.

Radiologic findings associated with mucoid degeneration of the anterior cruciate ligament.

INTRODUCTION: Mucoid degeneration (MD) of the anterior cruciate ligament (ACL) is a well-recognized pathology characterized by the degradation of collagen fibers and infiltration of a mucoid-like substance. This study is to determine the anatomical associated factors for MD-ACL using radiographic and magnetic resonance imaging (MRI). MATERIALS AND METHODS: This was a retrospective study on patients who had undergone knee arthroscopy between 2011 and 2020. The patients with MD-ACL were defined and enrolled by the MRI and arthroscopy. Eventually, 52 patients in the MD-ACL group (group 1) and 52 patients in the control group (group 2) were enrolled, following sex and age matching. Radiologic evaluation included the assessment of Kellgren-Lawrence (K-L) grade, mechanical hip-knee-ankle (HKA) angle, posterior tibial slope (PTS) angle, and Insall-Salvati ratio. The notch width index and transverse notch angle were measured on MRI, and the grade of trochlear dysplasia was defined. Logistic regression analysis, receiver operating characteristic (ROC) curves, and area under curve (AUC) were performed. RESULTS: The ROM was significantly decreased in group 1, whereas the PTS angle was significantly larger in group 1. Combined ganglion cysts of ACL were found in 42/52 patients (80.7%) in group 1. The risk of MD-ACL was associated with a steeper PTS angle, increased Insall-Salvati ratio, male sex, higher K-L grade, and decreased transverse notch angle and notch width index. The cutoff values in ROC analysis were found to be ≤ 28.27% for the notch width index (AUC, 0.849; p < 0.001), > 12.2° for the PTS angle (AUC, 0.765; p < 0.001), and ≤ 47.4° for the transverse notch angle (AUC, 0.711; p < 0.001), but not significant for Insall-salvati ratio. CONCLUSION: A steeper PTS angle, decreased notch width index, and transverse notch angle are significantly associated with the presence of MD-ACL. These factors should be considered during diagnosis or when determining the treatment strategy for symptomatic MD-ACL patients. LEVEL OF EVIDENCE: Level IIIb.

Risk factors for increased perioperative blood loss during total knee arthroplasty in patients with haemophilia.

INTRODUCTION: Currently, there is a paucity of literature describing the risk factors for increased perioperative blood loss (PBL) during total knee arthroplasty (TKA) in haemophilia. Furthermore, no studies have analysed coagulation factor levels that affect PBL. AIM: To identify the risk factors for increased PBL by incorporating coagulation factor levels following TKA in patients with haemophilic arthropathy. METHODS: A total of 92 TKA (78 haemophilia A and 14 haemophilia B) were performed for haemophilic arthropathy. PBL was calculated using the haemoglobin (Hb) balance method, and patients were categorised into two groups: group H (higher blood loss than the mean PBL, n = 36) and group L (lower blood loss than the mean PBL, n = 56). Body mass index (BMI), operation day Hb, haematocrit and coagulation factor level (VIII or IX) were analysed, including demographic and laboratory data. RESULTS: The mean PBL volume during TKA for haemophilic arthropathy of the knee was 542.3 ± 361.7 mL. Multivariate analysis revealed that lower haematocrit on the operation day (odds ratio [OR], .633; 95% confidence interval [CI], .511-.786; p < .001) and coagulation factor level (OR .970, CI .941-.999; p = .046) were independent risk factors for increased PBL. Receiver-operating characteristic analysis identified these cutoff values for predicting increased PBL: operation day coagulation factor level 93.5% (sensitivity, 70.4%; specificity, 67.6%) and haematocrit level of 38.2% (sensitivity, 85.7%; specificity, 80.6%). CONCLUSIONS: The PBL increased as haematocrit and coagulation factor levels decreased on the operation day. A coagulation factor level <93.5% or haematocrit level of <38.2% may be a significant risk factor for increasing PBL. LEVEL OF EVIDENCE: Level IV, Case Series, Treatment Study.

Serial Improvement of Medial Meniscus Extrusion Following Medial Open-Wedge High Tibial Osteotomy Does Not Correlate With Clinical Outcomes and Arthroscopic Articular Cartilage Improvement.

PURPOSE: To assess serial change up to 2 years in medial meniscus extrusion (MME) following medial open-wedge high tibial osteotomy (MOWHTO) and to determine whether postoperative changes in MME correlated with clinical outcomes and arthroscopic articular cartilage status. METHODS: This study included 26 patients from December 2016 to March 2018 who underwent MOWHTO for primary medial osteoarthritis with varus malalignment. Second-look arthroscopy with plate removal was performed at postoperative 2 years. MME was consecutively measured using coronal magnetic resonance imaging at preoperative and postoperative 3 months, 6 months, 1.5 years, and 2 years. We also assessed which preoperative parameters could reflect the postoperative changes in MME and evaluated whether postoperative clinical outcomes and arthroscopic articular cartilage improvement would be influenced by the MME changes. RESULTS: Regarding the postoperative serial changes in MME values, significant improvement in MME was noted from postoperative 6 months (P = .003), and thereafter, mean MME was further improved with time until postoperative 2 years (P < .001). Regarding the correlation between preoperative parameters and MME changes, preoperative medial proximal tibial angle (MPTA) showed significant correlations in univariate and multivariate analysis (P = .004 and P = .004, respectively). Meanwhile, changes in MME were not correlated with postoperative clinical outcomes or arthroscopic articular cartilage improvement. CONCLUSION: After MOWHTO, MME improved with time and was significantly correlated with preoperative MPTA. However, the changes in MME after MOWHTO did not reflect postoperative clinical and arthroscopic articular cartilage improvement. LEVEL OF EVIDENCE: IV, case series.

Steep posterior lateral tibial slope, bone contusion on lateral compartments and combined medial collateral ligament injury are associated with the increased risk of lateral meniscal tear.

PURPOSE: To determine the risk factors for lateral meniscus and root tears in patients with acute anterior cruciate ligament (ACL) injuries. METHODS: A total of 226 patients undergoing acute ACL reconstruction were included in the study sample. Exclusion criteria were revisions, fractures, chronic cases, and multiple ligament injuries, with the exception of medial collateral ligament (MCL) injuries. The patients were divided into groups based on the presence of lateral meniscus and root tears by arthroscopy. Binary logistic regression was used to analyze risk factors including age, sex, body mass index (BMI), injury mechanism (contact/non-contact), Segond fracture, side-to-side laxity, location of bone contusion, medial and lateral tibial and meniscal slope, mechanical axis angle, and grade of pivot shift. RESULTS: Overall lateral meniscus (LM) tears were identified in 97 patients (42.9%), and LM root tears were found in 22 patients (9.7%). The risk of an LM tear in ACL-injured knees increased with bone contusion on LTP (odds ratio [OR], 3.5; 95% confidence interval [CI] 1.419-8.634; P = 0.007), steeper lateral tibial slope (OR, 1.133; 95% CI 1.003-1.28; P = 0.045), MCL injury (OR, 2.618; 95% CI 1.444-4.746; P = 0.002), and non-contact injury mechanism (OR, 3.132; 95% CI 1.446-6.785; P = 0.004) in logistic regression analysis. The risk of LM root tear in ACL-injured knees increased with high-grade pivot shift (OR, 9.127; 95% CI 2.821-29.525; P = 0.000) and steeper lateral tibial slope (OR, 1.293; 95% CI 1.061-1.576; P = 0.011). CONCLUSION: The increased risk of LM lesions in acute ACL-injured knees should be considered if significant risk factors including bone contusion on lateral compartments, MCL injury, and a steeper lateral tibial slope are present. Moreover, high-grade rotational injury with steeper lateral tibial slope are also significant risk factors for LM root tears, and therefore care should be taken by clinicians not to miss such lesions. LEVEL OF EVIDENCE: III.

New Classification for Periprosthetic Distal Femoral Fractures Based on Locked-Plate Fixation Following Total Knee Arthroplasty: A Multicenter Study.

BACKGROUND: This study aimed to establish a new classification using locked-plate fixation for periprosthetic distal femoral fracture (PDFF) following total knee arthroplasty (TKA) and to determine when dual locked-plate fixation is necessary through defining this classification. METHODS: One-hundred fifteen consecutive PDFFs that underwent operative treatment were reviewed from 2011 to 2019 with minimum 1-year follow-up. Most PDFFs were fixed with single or dual locked-plate fixations using the minimally invasive plate osteosynthesis technique. Based on preoperative radiographs, PDFFs were classified according to the level of main fracture line relative to the anterior flange of femoral component: type I and II, main fracture line located proximal and distal to the anterior flange; and type III, component instability regardless of fracture line requiring revisional TKA. Furthermore, type II fractures were subclassified based on the direction of fracture beak as follows: type IIL, lateral-beak; type IIM, medial-beak. The incidence, treatment methods, and complications were analyzed according to the classification. RESULTS: Incidences of type I, IIL, IIM, and III were 64.4%, 8.7%, 24.3%, and 2.6%, respectively. Meanwhile, most PDFFs in type I and II were treated with lateral single locked-plate fixations, except for type IIM, which was treated with either single or dual locked-plate fixations. Overall complications were significantly higher in type II (28.9%) than in type I (10.8%, P = .019). In type IIM, bone union-related complications were significantly higher in single locked-plate fixation (50.0%) than in dual locked-plate fixation (5.6%; P = .013). CONCLUSION: The new classification provides practical and obvious strategies for the treatment of PDFF following TKA using locked-plate fixation. For type IIM fracture, dual plate fixation is necessary to prevent fixation failure or nonunion.

Tranexamic acid in a periarticular multimodal cocktail injection for blood management in total knee arthroplasty: a prospective randomized study.

BACKGROUND: This study aimed to assess the efficacy of tranexamic acid (TXA) mixed in a periarticular multimodal cocktail (PAMC) as a topical administration and to determine whether combined use of intravenous and topical administration is more effective than a single administration of TXA. METHODS: A total of 240 patients who underwent primary total knee arthroplasty (TKA) was enrolled for this prospective randomized controlled study. Patients were divided into three groups of 80 patients each. Baseline data were comparable for all groups. Average follow-up was 18.7 months. Group 1 consisted of patients who received intravenous (IV) TXA, Group 2 patients were those who received TXA in a PAMC injection for topical administration, and Group 3 consisted of patients who received a combination of both intravenous and topical administration of TXA. Primary outcomes were postoperative hemoglobin drop and amount of suction drainage. Secondary outcomes were estimated blood loss (EBL), postoperative transfusion rate, and complications. RESULTS: The mean postoperative hemoglobin drop was significantly lower in Group 3 (2.13 ± 0.77 g/dL, p=0.004), and there was no difference between Group 1 and Group 2 (2.56 ± 1.07 g/dL vs 2.55 ± 0.86 g/dL, p=0.999). The mean drainage amount was significantly lower in Group 3 (326.58 ± 57.55 ml, p<0.001), and there was no difference between Group 1 and Group 2 (367.93 ± 87.26 ml vs 397.66 ± 104.10 ml, p=0.072). Similarly, the mean EBL was significantly lower in Group 3 (p=0.003), and there was no significant difference between Group 1 and Group 2 (p=0.992). There were no significant differences in requirement for postoperative transfusion rate or incidence of complications among the three groups. CONCLUSION: TXA mixed in a PAMC injection showed a similar effect to IV administration of TXA following TKA. Furthermore, combined use of both IV and PAMC injection provided better perioperative bleeding control with similar safety in patients without relevant comorbidities. TRIAL REGISTRATION: WHO ICTRP identifier KCT0005703 . Retrospectively registered: 12/24/2020.

Medial Meniscus Posterior Root Tear Does Not Affect the Outcome of Medial Open-Wedge High Tibial Osteotomy.

BACKGROUND: This study aimed to verify whether the presence of medial meniscus posterior root tear (MMPRT) affects the clinical and radiographic outcomes of medial open-wedge high tibial osteotomy (MOWHTO) compared to the patients without MMPRT for over a midterm follow-up. METHODS: One hundred fifty-six knees were retrospectively enrolled that underwent MOWHTO and second-look arthroscopy concomitantly with a minimum 5 years of follow-up. Seventy-four knees with MMPRT (MMPRT group) were identified. Eighty-two knees with intact MMPR were assigned to another group (MMPRI group). All knees with torn medial meniscus with or without MMPRT had an arthroscopic partial meniscectomy during the MOWHTO. Clinical evaluation included range of motion, American Knee Society scores, and Western Ontario and McMaster Universities Osteoarthritis Index scores. Radiologically, the Kellgren-Lawrence grade was assessed preoperatively and at the latest follow-up. Cartilage status was also compared through the 2-stage arthroscopy according to the International Cartilage Repair Society grading. RESULTS: Average age at operation was 55.8 years (range 42-67), and the average follow-up period was 82.2 months (range 60-148). There were no significant differences in clinical outcomes between the groups. Postoperative changes in Kellgren-Lawrence grade and arthroscopic cartilage status showed no significant differences between the groups. Resected MMPR was remodeled in 41.9% (31/74) of the MMPRT group through the second-look arthroscopy. CONCLUSION: MMPRT does not affect the clinical and radiologic outcomes of MOWHTO compared to those patients without MMPRT over a mid-term follow-up.

Comparison of risk for postoperative hyperextension between cruciate retaining and posterior stabilized total knee arthroplasties.

INTRODUCTION: The incidence of postoperative hyperextension and factors affecting hyperextension needs to be investigated separately for cruciate retaining (CR) and posterior stabilized (PS) total knee arthroplasties (TKAs), because the mechanism for preventing hyperextension is different according to the bearing design. The purpose of the study was to compare the incidence of postoperative hyperextension between CR and PS TKAs and analyze the factors affecting the postoperative hyperextension. METHODS: Matched 213 CR and PS TKAs with Persona® prosthesis were retrospectively reviewed. The preoperative demographics, clinical and radiographic knee condition, and pelvic incidence were similar between groups. Appropriate knee extension (0°-5°), confirmed with a goniometer, was achieved intraoperatively. The knee sagittal angle was radiographically measured preoperatively and at 2 years postoperative. The incidence of hyperextension (sagittal angle < - 5°) was investigated. The factors affecting the postoperative hyperextension were analyzed in terms of age, sex, preoperative mechanical axis, knee sagittal angle, postoperative posterior tibial slope (PTS), change of posterior femoral offset, and pelvic incidence. RESULTS: The knee sagittal angle was not significantly different preoperatively between CR and PS TKAs. The postoperative knee sagittal angle was 2.9° in CR TKAs and 4.4° in PS TKAs (p = 0.004). The incidence of postoperative hyperextension was 11.7% (25/213) in CR TKAs and 4.2% (9/213) in PS TKAs (p = 0.007). The preoperative sagittal angle, postoperative PTS, and pelvic incidence were the significant factors affecting the postoperative hyperextension in CR TKAs (odds ratio 0.869, 2.205, and 1.045, respectively); the preoperative sagittal angle was only the significant factor in PS TKAs (odds ratio 0.857) CONCLUSIONS: Postoperative knee hyperextension occurred more frequently and was affected by more factors in CR TKAs than PS TKAs. Efforts to avoid hyperextension and closed observation are required in TKAs performed in patients with the risk factors. LEVEL OF EVIDENCE: III.

Load imbalances existed as determined by a sensor after conventional gap balancing with a tensiometer in total knee arthroplasty.

PURPOSE: To evaluate intercompartmental load intraoperatively with a sensor after conventional gap balancing with a tensiometer during total knee arthroplasty (TKA). METHODS: Fifty sensor-assisted TKA procedures were performed prospectively between August and September 2018 with a cruciate-retaining prosthesis. After applying a modified measured resection technique, conventional balancing between resected surfaces was achieved. The equal and rectangular flexion-extension gaps were confirmed using a tensiometer at 90° and 5°-7° (due to posterior tibial slope) of knee flexion. Then, the load distribution was evaluated intraoperatively with a sensor placed on trial implants in the positions of knee flexion (90° flexion) and extension (10° flexion). RESULTS: The proportion of coronal load imbalance (medial load - lateral load ≥ ± 15 lb) was 56% in extension and 32% in flexion (p = 0.023). The proportion of sagittal load imbalance (extension load - flexion load ≥ ± 15 lb) was 36% in the medial compartment and 4% in the lateral compartment (p < 0.001). An additional procedure for load balancing was performed in 74% of knees. CONCLUSIONS: Coronal and sagittal load imbalances existed as determined by the sensor even after the achievement of appropriate conventional gap balance. The additional rebalancing procedure was performed for balanced loads in 74% of the knees after conventional balancing. The use of an intraoperative load sensor offers the advantage of direct evaluation of the load on TKA implants. LEVEL OF EVIDENCE: IV.

Long-Term Results of Periacetabular Rotational Osteotomy Concomitantly With Arthroscopy in Adult Acetabular Dysplasia.

BACKGROUND: Although the long-term results of periacetabular osteotomy in acetabular dysplasia have been well documented, there is paucity in reports on the long-term outcomes of periacetabular osteotomy with simultaneous hip arthroscopy. This study aimed to assess the cumulative 10-year outcomes of periacetabular rotational osteotomy with concomitant hip arthroscopy. METHODS: Through an arthroscopic procedure, the status of the labrum was assessed, and torn labrum was debrided. Evaluations on survival from conversion to total hip arthroplasty and success in radiographic and clinical long-term results were completed in 39 hips (36 patients). Acetabular parameters (center-edge angle, Sharp angle, acetabular-head index, and head lateralization index), Tönnis grades on radiograph, Harris Hip Score, and range of motion of the hip were evaluated. Survivorship analyses were evaluated with the Kaplan-Meier method. RESULTS: Thirty-eight hips (97.4%, 95% confidence interval 0.832-0.996) were preserved for 12.8 ± 1.7 years on average, and only 1 hip was converted to total hip arthroplasty at 7.8 years. All the acetabular parameters were improved (P < .001). Twenty-eight hips (71.8%) showed unchanged or improved Tönnis grades at the latest follow-up. The average Harris Hip Score was significantly better than the preoperative value (P < .001), and range of motion was not significantly different until the latest follow-up. CONCLUSION: Sufficient acetabular reorientation, such as periacetabular rotational osteotomy, with concomitant arthroscopic debridement showed successful long-term outcomes for acetabular dysplasia in adults.

Long-term survival is similar between closed-wedge high tibial osteotomy and unicompartmental knee arthroplasty in patients with similar demographics.

PURPOSE: Long-term clinical and radiographic results and survival rates were compared between closed-wedge high tibial osteotomy (HTOs) and fixed-bearing unicompartmental knee arthroplasty (UKA) in patients with similar demographics. METHODS: Sixty HTOs and 50 UKAs completed between 1992 and 1998 were retrospectively reviewed. There were no significant differences in pre-operative demographics. The mean follow-up period was 10.7 ± 5.7 years for HTO and 12.0 ± 7.1 years for UKA (n.s.). The Knee Society knee and function scores, WOMAC, and range of motion (ROM) were investigated. The mechanical axis and femorotibial angle were evaluated. Kaplan-Meier survival analysis was performed (failure: revision to TKA) and the failure modes were investigated. RESULTS: Most of the clinical and radiographic results were not different at the last follow-up, except ROM; ROM was 135.3° ± 12.3° in HTO and 126.8° ± 13.3° in UKA (p = 0.005). The 5-, 10-, 15-, and 20-year survival rates were 100%, 91.0%, 63.4%, and 48.3% for closed-wedge HTO, respectively, and 90.5%, 87.1%, 70.8%, and 66.4% for UKA (n.s.). The survival rate was higher than that for UKA until 12 years post-operatively but was higher in UKAs thereafter, following a remarkable decrease in HTO. The most common failure mode was degenerative osteoarthritic progression of medial compartment in HTO and femoral component loosening in UKA. CONCLUSIONS: Long-term survival did not differ significantly between closed-wedge HTO and fixed-bearing UKA in patients with similar pre-operative demographics and knee conditions. The difference in post-operative ROM and failure mode should be considered when selecting a procedure. LEVEL OF EVIDENCE: III.

An intraoperative load sensor did not improve the early postoperative results of posterior-stabilized TKA for osteoarthritis with varus deformities.

PURPOSE: In the present study, the early results of sensor-assisted versus manually balanced posterior-stabilized total knee arthroplasty (TKA) for osteoarthritis with varus deformities were prospectively compared. METHODS: Fifty patients undergoing sensor-assisted TKA (group S) and 50 patients receiving manually balanced TKA (group M) were prospectively compared. The groups did not differ in terms of demographics, preoperative clinical status, or severity of deformity. The knee and function scores (KS and FS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and range of motion (ROM) were evaluated clinically. The mechanical axes and positions of components were assessed radiographically. In sensor-assisted TKA, the medial and lateral compartment loads were compared based on the patellar positions of inversion and eversion. RESULTS: There was no between-group difference in the postoperative KS or FS (n.s., respectively). The average postoperative WOMAC score was 17.0 in group S and 18.0 in group M (n.s.). The ROM was 131.2° in group S and 130.8° in group M (n.s.). Neither the postoperative alignment of the mechanical axis nor the component positioning differed between the groups (n.s.). In sensor-assisted TKA, the difference between the medial and lateral compartment loads was less than 15 lbs (6.8 kg) in each knee. The lateral compartment load increased after patellar eversion (p < 0.001). CONCLUSION: There are concerns about the cost-benefit ratio of the intraoperative load sensor, despite its advantage of more precisely assessing ligament balance without patellar eversion, which resulted in a smaller lateral gap. A long-term follow-up study with a large cohort is required. LEVEL OF EVIDENCE: II.

Midbody of the medial meniscus as a reference of preservation in partial meniscectomy for complete discoid lateral meniscus.

PURPOSE: To evaluate the postoperative size of discoid lateral meniscus using magnetic resonance imaging (MRI) after partial meniscectomy relative to the size of medial meniscus midbody. METHODS: This study included 48 patients who underwent arthroscopic partial meniscectomy with or without repair for symptomatic complete discoid meniscus. The intraoperative size of midbody of medial meniscus was used as a reference for partial meniscectomy. MRIs were performed pre- and postoperatively. Quantitative evaluations of the height, width, extrusion of the meniscus, and relative percentage of extrusion in the coronal and sagittal planes were completed. Demographic data, preoperative shift, type of shift, and operative technique were analyzed while considering the remaining meniscus. Logistic regression analyses were used. RESULTS: The mean remaining discoid meniscal width in the coronal plane of MRI was not significantly different from the width of midbody of medial meniscus (9.1 ± 4.2 mm vs. 9.4 ± 1.4 mm, n.s.) Absolute meniscal extrusion and relative percentage of extrusion in the coronal plane and the ratio of t meniscus in sagittal plane of the final MRI were significantly increased as compared with the preoperative MRI. Preoperative shift was a risk factor for the reduction of remaining meniscal width (odds ratio 11.997, p = 0.016, 95% CI 1.586-90.737). CONCLUSION: The size of midbody of medial meniscus could be a reference for partial meniscectomy in symptomatic complete discoid meniscus. Preoperative shift represents a risk factor for decreased remaining meniscal width. These findings could be helpful in ensuring appropriate surgical planning and explaining poor prognostic factors. LEVEL OF EVIDENCE: Prospective cohort study, Level II.

Robot-Assisted Total Knee Arthroplasty Does Not Improve Long-Term Clinical and Radiologic Outcomes.

BACKGROUND: Whether robot-assisted total knee arthroplasty (TKA) improves the accuracy of radiographic alignment leading to improved patient satisfaction and implant survivorship in the long term has thus far been inconclusive. METHODS: We retrospectively compared the long-term clinical and radiological outcomes of 84 knees that had undergone robot-assisted TKA using ROBODOC vs 79 knees that had undergone conventional TKA. The mean duration of the follow-up period was 129.1 months (range: 108-147 months). Clinical outcomes were evaluated using the Knee Society Score and 36-item Short Form Survey, as well as by assessing the range of motion, operation time, and complications. Radiologic outcomes were evaluated by assessing the hip-knee-ankle angle, coronal and sagittal alignments of the femoral and tibial components, and any radiologic abnormalities such as loosening or osteolysis. RESULTS: There was no significant difference in clinical outcomes between the two groups. The prevalence of an outlier for the hip-knee-ankle angle in the robot-assisted group was 10.7%, whereas it was 16.5% in the conventional group (P = .172). The other component alignments (α°, ß°, γ°, δ°) revealed a tendency toward a lower rate of outliers in the robot-assisted group, but without statistical significance (P > .05). In addition, there was no significant difference in complications, including revision surgery, between both groups. CONCLUSION: Robot-assisted TKA does not improve long-term clinical or radiologic outcomes compared with conventional TKA.

Increased Posterior Tibial Slope After Medial Open-Wedge High Tibial Osteotomy May Result in Degenerative Changes in Anterior Cruciate Ligament.

BACKGROUND: This study aimed at evaluating changes in posterior tibial slope angle (PTSA) and the anterior cruciate ligament (ACL) before and after medial open-wedge high tibial osteotomy (MOWHTO) through 2-staged arthroscopic findings and verified whether the ACLs would be affected by the changed PTSA. We also evaluated which predisposing factors could influence ACL changes after MOWHTO. METHODS: From July 2010 to March 2016, 164 knees that could follow the second-look arthroscopy at the time of plate removal were enrolled. Radiologically, preoperative and postoperative hip-knee-ankle angle, femorotibial angle, medial proximal tibial angle, and PTSA were evaluated. Based on our previous study, we assessed the ACL using the macroscopic grading system (normal, abnormal degenerative, and partially ruptured ACL) by first- and second-look arthroscopy and compared it before and after HTO. The correlation between changes in PTSA (△PTSA) and ACL was evaluated. We also assessed predisposing factors that might affect ACL changes. RESULTS: Mean age at the time of osteotomy was 57.2 ± 5.1 years and time interval between the 2-stage arthroscopies was 26.3 ± 4.0 months. PTSA significantly increased after MOWHTO (P < .001). ACL stage at second-look arthroscopy was significantly progressed compared to first-look findings (P < .001). △PTSA was larger in the progressed group (2.1°; P < .001). Multivariate logistic regression indicated that greater body mass index (odds ratio, 1.2; P = .029) and larger △PTSA (odds ratio, 1.3; P = .008) were predisposing factors. CONCLUSION: Increased posterior tibial slope following MOWHTO may result in degenerative ACL changes. Greater body mass index and larger △PTSA were predisposing factors for ACL degeneration after MOWHTO.

Diagnostic Accuracy of Sequential Arthroscopic Approach for Ramp Lesions of the Posterior Horn of the Medial Meniscus in Anterior Cruciate Ligament-Deficient Knee.

PURPOSE: To document the diagnostic accuracy and steps for sequential arthroscopic exploration of ramp lesions-peripheral tear within 4 mm of meniscocapsular junction of medial meniscus-associated with anterior cruciate ligament (ACL) injury. METHODS: This was a prospective consecutive study of 195 primary ACL reconstructions with arthroscopic exploration for ramp lesion in 4 steps: (1) standard exploration through the anterolateral portal, (2) through the intercondylar space using a 30° arthroscope, (3) through the intercondylar space using a 70° arthroscope, and (4) after creation of a posteromedial portal. Acute (<3 months) and chronic case (>3 months) groups were compared, and the sensitivity and specificity of magnetic resonance imaging (MRI) were assessed. RESULTS: Overall, 50 patients (26.6%) were confirmed as having a ramp lesion. After step 1, only 19 cases (38%) were identified as a ramp lesion. After step 2, 24 cases (48%) were found, and the sensitivity of step 2 was estimated at 48%. After step 3, an additional 26 cases (52%) were identified. No more additional cases of ramp lesion were found after step 4. There were statistically significant differences between steps 2 and 3 (P = .001), but no differences between steps 1 and 2, or steps 3 and 4. Although there were no statistical differences in overall prevalence for acute (28/128, 21.8%) and chronic (22/67, 32.8%) groups (P = .136), the incidence of ramp lesion confirmed through the standard portal approach was found to be significantly correlated with chronic group (odds ratio: 2.95, P = .023). The sensitivity and specificity of preoperative MRI were 84% and 95.17%. CONCLUSIONS: Many ramp lesions could not be diagnosed through the standard portal and intercondylar space using a 30° arthroscope. Posteromedial inspection using a 70° arthroscope has improved the diagnostic accuracy for ramp lesion without direct exploration through the posteromedial portal. Care should be taken to identify ramp lesions when ACL reconstruction is performed. LEVEL OF EVIDENCE: Level I, diagnostic study of consecutive patients.

Extra-articular Lateral Hinge Fracture Does Not Affect the Outcomes in Medial Open-Wedge High Tibial Osteotomy Using a Locked Plate System.

PURPOSE: To compare the radiologic and clinical outcomes in patients with and without lateral hinge fractures (LHFs) during medial open-wedge high tibial osteotomy (MOWHTO) using a locked plate system, as well as to assess whether LHFs could affect the midterm outcomes. METHODS: From May 2008 to November 2015, 164 knees underwent MOWHTO using a locked plate system for the treatment of knee osteoarthritis. LHFs were recognized by radiographs during or after the high tibial osteotomy and were not additionally treated. In all patients, we applied the same rehabilitation protocol that allowed full weight bearing at 6 weeks. Patients were divided into LHF (types I and II) and nonfracture groups. Radiologically, we compared any serial changes in the hip-knee-ankle angle, femorotibial angle, medial proximal tibial angle, and posterior tibial slope angle from the immediate postoperative radiographs to the final radiographs. The union process of the osteotomy site among the groups was also evaluated. Clinically, the postoperative American Knee Society Score and knee range of motion at latest follow-up were compared. Postoperative complications were also evaluated. RESULTS: The average age at operation was 56.0 years (range, 42-67 years), and the average follow-up period was 62.2 months (range, 24-120 months). LHFs were observed in 37 knees (22.6%) and were divided into the type I (16 knees) and type II (21 knees) groups. All groups showed no significant changes in serial evaluations of the postoperative hip-knee-ankle angle, femorotibial angle, medial proximal tibial angle, and posterior tibial slope angle. The improvements in the American Knee Society Score and knee range of motion were not significantly different among the groups. No patients showed correction loss or union problems. CONCLUSIONS: Type I and II LHFs in MOWHTO using a medial locked plate system and relatively conservative rehabilitation protocol with full weight-bearing walking commenced at 6 weeks postoperatively showed no radiologic changes or functional deterioration during midterm follow-up. LEVEL OF EVIDENCE: Level IV, case series.

Arthroscopic meniscus repair for recurrent subluxation of the lateral meniscus.

PURPOSE: This study was undertaken to diagnose and to document the clinical results and technical aspects of arthroscopic meniscus repair for recurrent subluxation with peripheral tears around the popliteal hiatus of the lateral meniscus. METHODS: Twenty-three patients (24 knees) with symptomatic recurrent subluxation of the lateral meniscus treated by arthroscopic meniscus repair were included. The inclusion criteria were: (1) patients with knee pain, locking or snapping symptoms despite 3 months of conservative treatment; (2) non-discoid lateral meniscus; (3) stable knee, and (4) tears involving the red-white or red-red zone. All tears were repaired by either the modified all-inside suture technique only or a combination of the modified all-inside and modified outside-in suture techniques. Clinical results were evaluated preoperatively and at final follow-up according to Tegner activity level, Lysholm knee, and Hospital for Special Surgery (HSS) scores. RESULTS: No reoperations were required after a median follow-up of 41 months (range 24-124). Although recurrence of a locking episode was documented in one knee and catching sensations were experienced in three knees, those patients did not require reoperation. At the last follow-up, the median Tegner activity level had improved significantly from 4 (range 2-6) to 7 (range 3-10, p < 0.0001), the median Lysholm knee score improved from 76 (range 25-90) preoperatively to 94 (range 76-100) at final follow-up (p < 0.0001), and the median preoperative HSS score improved from 86 to 95 at final follow-up (p < 0.0001). CONCLUSION: The described arthroscopic meniscus suture technique is effective for treating symptomatic recurrent subluxation of the lateral meniscus without any complications or recurrence. Clinical suspicion and understanding of recurrent subluxation with lateral meniscus are important to diagnose the disease especially when definite meniscal tear signs are absent on magnetic resonance imaging. LEVEL OF EVIDENCE: IV.