Reduced physiological extrusion of the medial meniscus in axial load-bearing condition in anterior cruciate ligament deficiency.

PURPOSE: In this study, ultrasonography was used to measure medial meniscus (MM) extrusion under weight-bearing and nonweight-bearing conditions in both anterior cruciate ligament (ACL)-deficient and ACL-intact knee groups. This study aimed to determine the possible differences between these groups with an eventual impact on meniscal tears in ACL-deficient knees. METHODS: A total of 107 patients who underwent ACL reconstructive surgery between June 2022 and April 2023 were enroled. After applying exclusion criteria, 37 patients met the conditions for inclusion in the study and formed the ACL deficiency group (Group D). Of the 141 patients presenting to an outpatient clinic who agreed to have ultrasonography conducted on their nondiscomforting contralateral knee, 37 patients matched for age, sex, hip-knee-ankle angle and body mass index with Group D patients were selected for the ACL intact group (Group I). Ultrasonography was used to measure MM extrusion in weight-bearing and nonweight-bearing conditions for all participants. RESULTS: Seventy-four patients were included in the study (n = 37 per group). The supine position showed an MM extrusion of 1.2 ± 0.7 mm in Group I and 1.2 ± 0.7 mm in Group D (not significant). In the standing position, MM extrusion measured 2.0 ± 0.6 mm in Group I and 1.3 ± 0.8 mm in Group D. The difference in extrusion (Δextrusion) between the two positions was 0.8 ± 0.6 in Group I and 0.1 ± 0.2 in Group D, with statistical significance (p < 0.01). A consistent reduction in MM extrusion during weight-bearing was observed in patients with ACL deficiency, irrespective of the duration of ACL deficiency, age, sex and BMI. CONCLUSION: ACL deficiency did not significantly impact MM extrusion during nonweight-bearing conditions; however, less MM extrusion was observed in response to axial loading conditions. These findings indicate altered MM biomechanics due to increased anterior-posterior meniscal motion and rotational instability after ACL injury. LEVEL OF EVIDENCE: Level III.

Direct Solution-Phase Synthesis and Functionalization of 2D WSe2 for Ambient Stability.

2H phase tungsten diselenide (WSe2 ) is a p-type 2D semiconductor from the transition metal dichalcogenides (TMDs) family with unique optoelectrical properties. Solution phase production of atomically thin WSe2 is challenging due to its instability under ambient conditions. We present a highly efficient and scalable solution method for simultaneously exfoliating and functionalizing WSe2 by leveraging the non-covalent interaction between mercapto-group and bulk WSe2 . Single and few-layer 2H phase pure WSe2 sheets of lateral size up to 5 µm with minimal basal plane defects, as revealed by XPS, Raman and FTIR spectroscopy, are produced in a water-ethanol mixture. Remarkably, WSe2 dispersion remains stable even at high concentrations (10 mg/mL) and exhibited high colloidal stability with a shelf-life exceeding a year. The findings from our study suggest that through precise manipulation of intercalation chemistry, mass production of solution-processable phase-sensitive 2D materials such as WSe2 can be achieved. This advancement holds great potential for facilitating their practical utilization in various real-world applications.

Single-incision bone bridge lateral meniscus allograft transplantation: preserving neurovascular safety with promising results for posterior horn distortion and graft maturation.

PURPOSE: This study aimed to investigate the graft maturation and safety of single-incision bone bridge lateral meniscus allograft transplantation (LMAT). METHODS: This study involved 35 patients who underwent LMAT between 2019 and 2020. All patients completed at least 2 years of follow-up (median 34 months; range 24-43) and underwent preoperative magnetic resonance imaging (MRI) to assess the trajectory safety of the leading suture passer and all-inside suture instrument (Fast-Fix). Graft status was evaluated according to the Stoller classification. RESULTS: Based on preoperative MRI measurements, the expected trajectory of the leading suture passer did not transect the common peroneal nerve (CPN), with the closest distance between the expected trajectory and CPN being 1.4 mm and the average distance being 6.8 ± 3.2 mm. The average distance from the lateral meniscal posterior horn (LMPH) to the popliteal neurovascular bundle (PNVB) was 7.4 ± 2.6 mm and the nearest was 4.8 mm. The expected trajectory of the all-inside suturing instrument did not transect the PNVB when the distance was at least 12 mm, from the most lateral margin of the posterior cruciate ligament (PCL). Grade 3 signal intensity in the posterior third of the allograft on MRI was observed in 6 of 35 (17.1%) patients. Amongst the grade 3 signal intensities in the posterior one-third of the allografts, 3 of the 35 (8.5%) LMATs had a distorted contour. CONCLUSION: The single-incision bone bridge LMAT technique introduced in this study is a convenient approach that preserves neurovascular safety and provides good results for the distortion of the posterior horn of the allograft and graft maturation. The safety zone for the penetrating devices during the procedure extended from 12 mm laterally to the most lateral margin of the PCL to the medial margin of the popliteal hiatus. LEVEL OF EVIDENCE: IV.

Additional Anterolateral Ligament Reconstruction Helps Patients Improve Dynamic Postural Stability in Revision Anterior Cruciate Ligament Reconstruction.

Background and Objectives: The goal in treating anterior cruciate ligament (ACL) injury especially in revision cases is return to sports activity by regaining dynamic postural stability. Among various methods to achieve this goal, additional anterolateral ligament reconstruction (ALLR) is gaining attention. The purpose of this study was to evaluate the effects of additional ALLR in revision ACL reconstruction (RACLR). Materials and Methods: Patients who underwent RACLR between July 2015 and June 2018 were enrolled. The exclusion criteria were less than 1-year follow-up, age older than 45 years, concomitant multiple ligament injuries, contralateral knee injury, subtotal or total meniscectomized state, and articular cartilage lesions worse than Outerbridge grade 3. Thirty-nine patients (20 patients; RACLR only (Group A), 19 patients; RACLR with additional ALLR (Group B)) were included. Clinical scores (Lysholm score, subjective International Knee Documentation Committee (IKDC) score, Tegner activity scale), isokinetic strength test, single-leg-hop for distance test (SLHDT), Y-balance test (YBT) were checked preoperatively and 1-year postoperatively. Results: Limb symmetry index values in YBT showed significantly better result in Group B 1-year postoperatively (Group A: 97.2 ± 4.0, Group B: 100.3 ± 2.9, p = 0.010), although there were no differences preoperatively between groups (Group A: 90.4 ± 6.7, Group B: 89.3 ± 5.5, p = 0.594). Regarding clinical scores, isokinetic strength tests, and SLHDT, there were no differences between groups preoperatively nor 1-year postoperatively. Conclusions: Additional ALLR in RACLR helped patients gain better dynamic postural stability at 1-year postoperative follow-up.

Patients with advanced lateral osteoarthritis can return to sports and work after distraction arthroplasty plus lateral meniscal allograft transplantation combined with cartilage repair.

PURPOSE: This study aimed to report return to sports (RTS) and return to work (RTW) outcomes after distraction arthroplasty (DA) plus lateral meniscal allograft transplantation (MAT) combined with cartilage repair in active patients with advanced osteoarthritis. It was hypothesised that DA combined with lateral MAT would improve clinical and radiological outcomes and enable RTS and RTW for most patients. METHODS: In total, 21 patients with advanced osteoarthritis (moderate to severe joint space narrowing at lateral edge on Rosenberg view and large cartilage defect of lateral femoral condyle) who underwent concomitant DA and MAT were retrospectively reviewed. Clinical outcomes were assessed using subjective knee scores [Lysholm score, International Knee Documentation Committee (IKDC) subjective knee score, and Tegner activity scale (TAS)] and functional tests (isokinetic extensor muscle strength test, single-leg vertical jump test, and single-leg hop for distance test). The rates of RTS, RTW, and satisfaction were evaluated. Radiological outcomes were assessed using magnetic resonance imaging (MRI) and X-ray (Rosenberg view). RESULTS: The mean age at surgery and mean follow-up duration were 37.2 ± 5.9 years and 37.1 ± 5.4 months, respectively. All improvements in subjective scores were statistically significant (p < 0.001). The Lysholm score improved from 58.3 ± 8.1 to 84.3 ± 8.2, the IKDC subjective score from 53.9 ± 10.4 to 78.0 ± 7.7, and the TAS from 4.0 ± 0.5 to 5.1 ± 0.8. The limb symmetry index (LSI) (%) of the extensor peak torque at an angular velocity of 60°/s improved from 67.3 ± 19.2 to 88.4 ± 20.3% (p = 0.001). The LSI of the single-leg vertical jump test and single-leg hop for distance test improved from 62.8 ± 21.3 to 87.7 ± 19.5% and from 63.9 ± 20.8 to 85.5 ± 18.1%, respectively (all, p < 0.001). All patients were able to return to any sports activity and work. However, 67% and 90.5% returned to their defined or desired level of sports activity and occupation intensity, respectively. Further, 76.2% were very satisfied or somewhat satisfied with the outcome at the last follow-up. The JSW increased by 0.8 ± 0.4 to 2.3 ± 0.6 mm (p = 0.005). In more than 90% of patients, > 50% of cartilage lesion was covered. The mean graft extrusion was 2.6 ± 1.0 mm. CONCLUSION: All patients who underwent distraction arthroplasty plus lateral MAT combined with cartilage repair returned to any sports and work at the last follow-up. Significant improvements in clinical outcomes and the radiographic joint space width were observed. However, the activity ability was somewhat reduced compared with the best preoperative level. This one-stage joint salvage treatment is a promising option for young and active patients with advanced OA who wish to return to high levels of sports activity and occupation intensity (≥ Tegner activity scale 4). LEVEL OF EVIDENCE: III.

Changes in Bone Marrow Lesions Following Root Repair Surgery Using Modified Mason-Allen Stitches in Medial Meniscus Posterior Root Tears.

Root repair can prevent osteoarthritis (OA) by restoring hoop tension in medial meniscus posterior root tears (MMPRTs). This study aims to investigate bone marrow edema (BME) lesions known to be associated with OA following MMPRTs. Methods: Thirty patients with transtibial pull-out repair were recruited. Subchondral BME lesions were evaluated using magnetic resonance imaging (MRI) at 1-year follow-ups. Participants were categorized into three groups: no change of BME lesions (group one), improved BME lesions (group two) and worsened BME lesions (group three). Clinical scores and radiological outcomes, specifically Kellgren-Lawrence grade, medial joint space width and cartilage grade and meniscal extrusion were evaluated and compared between groups. Results: After surgery, twenty-three patients with no BME, three patients with BME lesions on the medial femoral condyle, one patient with BME lesions on the medial tibia plateau and three patients with BME lesions on both were investigated. A total of 20 patients in group one (66.7%) showed no change in BME lesions. In group two, seven patients (23.3%) presented with improved BME lesions. Only three patients (10%) showed worsened BME lesions (group three). Moreover, Lysholm scores and the rate of progression of cartilage grades were significantly worse in group three patients. Meniscal extrusion was significantly reduced in group two, whereas extrusion was significantly progressed in group three. Conclusion: Patients with worsened BME lesions showed less favorable outcomes than other patients. A decrease in meniscal extrusion can have a positive effect on BME lesions after root repair.

Editorial Commentary: Efforts to Heal Meniscal Radial Tears Are Ongoing.

Meniscal radial tears are equivalent to the meniscectomized state. However, successful healing rates by current repair methods for meniscal radial tears are still not satisfactory. Several suture configurations that could approximate the tear gap and stabilize meniscal tissue have been developed to overcome the shortcomings of simple horizontal stitches and cross stitches. The hybrid stitch method, composed of horizontal stitches and vertical stitches, has been introduced. This method can provide stable fixation because the vertical stitches suture the bundle of circumferential fibers, and the vertical stitches act as rip stops for the horizontal stitches. However, it is still challenging to heal meniscal radial tears in avascular areas or complex tears. In treating radial tears, it is important not only to improve suture mechanics but also to promote biologic healing potential.

Preoperative varus alignment and postoperative meniscus extrusion are the main long-term predictive factors of clinical failure of meniscal root repair.

PURPOSE: No studies have been conducted to determine long-term predictors of clinical failure after surgical root repair. This study identified long-term prognostic factors of clinical failure after pull-out repair of medial meniscus posterior root tears (MMPRTs) at a minimum of 10 year follow-up. METHODS: A total of 37 patients who underwent MMPRT pull-out repair and had been observed for more than 10 years were recruited for this study. The mean follow-up period was 125.9 ± 21.2 months. Clinical failure of the procedures was defined as conversion to total knee arthroplasty (TKA). Participants were categorized into two groups: non-failure and failure groups. Various factors, including demographic features and radiologic findings, were analyzed and compared between the two groups. Meniscus extrusion was assessed at coronal magnetic resonance imaging preoperatively and 1 year postoperatively. Independent risk factors were determined by univariate analysis and logistic regression analysis. To determine the cut-off value for risk factors, the receiver-operating characteristic curve analysis was performed. RESULTS: In total, eight patients (22%) were converted to TKA during the follow-up period. With univariate analysis, statistically significant differences between two groups were observed in mechanical varus alignment (P = 0.018), rate of the number of patient with more meniscal extrusion values after surgery (P = 0.024), and the difference between the preoperative and 1-year postoperative value of meniscus extrusion (mm) (P = 0.010). In a logistic analysis, OR of mechanical varus alignment and differences in meniscus extrusion value before and 1 year after surgery was 1.5 (P = 0.048) and 3.7 (P = 0.034). The cut-off values of mechanical varus alignment and differences in meniscus extrusion values were 5 degrees and 0.7 mm. CONCLUSION: Clinically, preoperative varus alignment and increased meniscal extrusion after surgery were found to be predictive for a clinical failure after meniscal root repair in a long-term perspective. Thus, these negative prognostic factors should be taken into consideration for performing root repair in MMPRTs. LEVEL OF EVIDENCE: Level III.

An increasing trend of the number of meniscus allograft transplantation in Korea.

PURPOSE: Meniscus allograft transplantation (MAT) can be performed to treat symptomatic patients with meniscus-deficient knees. However, the current epidemiologic status of MAT is unknown in many countries, including Korea. This study aimed to investigate the national trends of MAT in Korea which covers MAT procedures by the Korean national health insurance system. METHODS: Information from the national database was acquired through the Korean Health Insurance Review and Assessment Service (HIRA) from 2010 to 2017. All patients encoded as MAT were included. The total number of MATs and their incidence per 100,000 persons were determined, and the results were stratified by age and sex. RESULTS: The total number of MATs and their incidence per 100,000 persons per year were 369 and 0.77, respectively, in 2010, which increased to 826 and 1.72, respectively, in 2017. The number of MATs increased by 124% over 8 years. The peaks for the total number of MATs and their incidence were seen in patients in their 20 s in 2010, but in 2017, the peaks were observed in patients who were in their 40 s. MAT was performed more frequently in males (61%) than in females (39%) over the study period. CONCLUSION: The total number of MATs and their incidence had increased by 124% between 2010 and 2017. The peak treatment age range for MAT changed from 20 years of age in 2010 to 40 years of age in 2017, and MAT was performed more frequently in males than in females. LEVEL OF EVIDENCE: IV.

Outcomes of Medial Meniscal Posterior Root Repair During Proximal Tibial Osteotomy: Is Root Repair Beneficial?

PURPOSE: To compare the clinical and radiologic outcomes and arthroscopic findings of proximal tibial osteotomy (PTO) alone versus PTO combined with medial meniscal posterior root repair (MMPRR). METHODS: Between October 2010 and September 2016, patients who underwent PTO and second-look arthroscopy at a minimum of 24 months postoperatively were reviewed. Patients were divided into group I (isolated PTO), group P (PTO with MMPRR using the pull-out technique), and group F (PTO and MMPRR using the side-to-side repair method). The subjective knee scores were assessed. Radiologic evaluation was based on the Kellgren-Lawrence grade. Healing of medial meniscal posterior root tears (good/loose/scar tissue/failed) and cartilage regeneration (excellent/good/poor) were assessed by arthroscopic examination. RESULTS: Mean clinical follow-up duration of group I (n = 22), P (n = 25), and F (n = 24) was 28.5 ± 5.7, 27.9 ± 6.2, and 26.3 ± 5.3 months, respectively. At final follow-up, Lysholm score, International Knee Documentation Committee subjective score, and Tegner activity scale significantly improved in all groups (P < .001), and subjective scores did not differ among the groups. The Kellgren-Lawrence grade progression showed no significant differences among 3 groups (P = .461). Good healing of medial meniscal posterior root tears was found in 24% and 12.5% of patients in groups P and F, respectively, and 0 in group I; there were significant differences between groups I and P (P < .001) and groups I and F (P < .001). Excellent cartilage regeneration in the medial femoral condyle and medial tibial plateau was found in 13.6% and 9.1% in group I, 24% and 12% in group P, and 16.7% and 8.3% in group F, respectively, without significant differences. CONCLUSIONS: Concurrent MMPRR during PTO appears to improve the arthroscopic appearance (healing of MMRPTs and cartilage regeneration) during second-look arthroscopy. However, concurrent MMPRR does not significantly improve clinical and radiologic outcomes at short-term follow-up. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Microfractures Versus a Porcine-Derived Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects: A Multicenter Randomized Controlled Trial.

PURPOSE: The purpose of this study was to evaluate the clinical efficacy and safety of treating patients with a cartilage defect of the knee with microfractures and porcine-derived collagen-augmented chondrogenesis technique (C-ACT). METHODS: One hundred participants were randomly assigned to the control group (n = 48, microfracture) or the investigational group (n = 52, C-ACT). Clinical and magnetic resonance imaging (MRI) outcomes were assessed 12 and 24 months postoperatively for efficacy and adverse events. Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) assessment was used to analyze cartilage tissue repair. MRI outcomes for 50% defect filling and repaired tissue/reference cartilage (RT/RC) ratio were quantified using T2 mapping. Clinical outcomes were assessed using the visual analogue scale (VAS) for pain and 20% improvement, minimal clinically important difference (MCID), and patient acceptable symptom state for Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee score. RESULTS: MOCART scores in the investigation group showed improved defect repair and filling (P = .0201), integration with the border zone (P = .0062), and effusion (P = .0079). MRI outcomes showed that the odds ratio (OR) for ≥50% defect filling at 12 months was statistically higher in the investigation group (OR 3.984, P = .0377). Moreover, the likelihood of the RT/RC OR becoming ≥1 was significantly higher (OR 11.37, P = .0126) in the investigation group. At 24 months postoperatively, the OR for the VAS 20% improvement rate was significantly higher in the investigational group (OR 2.808, P = .047). Twenty-three patients (52.3%) in the control group and 35 (77.8%) in the investigation group demonstrated more than the MCID of KOOS pain from baseline to 1 year postoperatively, with a significant difference between groups (P = .0116). CONCLUSION: In this multicenter randomized trial, the addition of C-ACT resulted in better filling of cartilage defect of the knee joint. LEVEL OF EVIDENCE: Level Ⅰ, Multicenter Randomized Controlled Trial.

Anatomic medial complex reconstruction in serious medial knee instability results in excellent mid-term outcomes.

PURPOSE: To evaluate the mid-term outcomes of anatomic medial complex reconstruction in cases of serious medial knee instability. METHODS: Between 2010 and 2013, 23 patients who underwent anatomic medial complex reconstruction with a minimum 5-year follow-up were included. The Lysholm score, International Knee Documentation Committee subjective knee form (IKDC SKF), and Tegner activity scale scores were evaluated. Clinical and functional tests included valgus and sagittal stress tests, isokinetic muscle strength test, single leg hop for distance test (SLDT), and single leg vertical jump test (SLVT). RESULTS: The mean follow-up duration was 77.2 ± 10.8 months. At final follow-up, the Lysholm score improved from 49.7 ± 10.2 to 93.4 ± 12.4; the IKDC SKF score, from 46.2 ± 8.7 to 90.5 ± 13.9; and median Tegner activity, from 5 (4-7) to 7 (4-10) (P < 0.001). The mean side-to-side difference on valgus stress radiographs was significantly reduced to 1.2 ± 0.7 mm postoperatively compared to 8.5 ± 1.6 mm preoperatively (P < 0.001). The mean side-to-side differences on anterior and posterior stress radiographs were significantly improved in concomitant ACL and PCL reconstructions, respectively (P < 0.001). Preoperatively, 17 patients (73.9%) had anteromedial rotatory instability (AMRI), but none had AMRI at the last follow-up. The extensor peak torque and Limb Symmetry Index (LSI, %) improved from 128.2 ± 42.9 to 225 ± 39.4 N m/kg and from 61.4 ± 19.6 to 88.7 ± 21.7%, respectively (P < 0.001). The LSI (%) for SLDT and SLVT improved from 56.8 ± 19.5 to 87.3 ± 14.2% and from 68.1 ± 21.1 to 91.1 ± 12.8%, respectively (P < 0.001). No patient had a restricted range of movement. CONCLUSION: Although posteromedial corner injuries that need medial complex reconstruction are extremely rare, proper anatomic medial complex reconstruction of the medial collateral and posterior oblique ligaments achieved satisfactory clinical and functional outcomes at mid-term follow-up in cases with chronic symptomatic valgus and rotatory laxity. LEVEL OF EVIDENCE: Case series, level IV.

Editorial Commentary: Save the Meniscal Root, Why Not?

The repair of the meniscal root in medial meniscal posterior root tears is receiving increasing interest as more and more research highlights the positive effects of this procedure on the biomechanical restoration of the meniscus. As a testament to the findings of these studies, an international consensus statement recently acknowledged, with several supporting findings from both biomechanical and clinical studies, the effectiveness of meniscal root repairs. Various root repair techniques have been developed with the overarching goal of restoring the structure and function of the meniscus. Yet several challenges such as obtaining robust and long-term healing of degenerative tissue and minimizing meniscal extrusion remain to be overcome.

Return to Sports and Clinical Outcomes After Arthroscopic Anatomic Posterior Cruciate Ligament Reconstruction With Remnant Preservation.

PURPOSE: To evaluate the clinical outcomes of transtibial posterior cruciate ligament reconstruction (PCLR) with remnant preservation in highly active patients and to investigate the rate of return to sports (RTS), quality of sports activities, and patient satisfaction. METHODS: Patients with a Tegner activity scale of >5 who underwent isolated PCLR from 2013 to 2016 with minimum 2-year follow-up were retrospectively reviewed. Single-bundle PCLR was performed using fresh frozen allograft irradiated with 50 kGy. Subjective assessments included the Lysholm score, subjective International Knee Documentation Committee score, and Tegner activity scale. A questionnaire elicited information associated with RTS and satisfaction. Functional tests included isokinetic muscle strength and single-leg hop tests. RESULTS: We evaluated 52 patients, with a mean (± standard deviation) follow-up duration of 29.5 ± 8.6 months. The subjective assessments and functional tests significantly improved postoperatively (all P < .001). Mean time to return to full sports activity was 9.7 ± 5.1 months. Thirty-eight (73.1%) and 45 (86.5%) patients could return to previous sports activities at 9 and 24 months, respectively. A sports-experience questionnaire indicated that 48% and 69.2% of the patients were participating with unlimited effort and performance, respectively, and no pain at 9 and 24 months. Multivariate analysis indicated that extensor deficit (odds ratio [OR] 4.2, 95% confidence interval [CI] 1.342 to 17.839), flexor deficit at 60°/s (OR 3.8, 95% CI 1.081 to 14.476), Limb Symmetry Index (%) for the single-leg vertical jump test (OR 2.2, 95% CI 1.212 to 9.227), and satisfaction (OR 2.8, 95% CI 1.186 to 10.281) were significantly associated with failure of not returning to preinjury sports activity levels at the 9-month follow-up. CONCLUSIONS: Arthroscopic anatomic PCLR with remnant preservation showed high rates of RTS and high patient satisfaction, as well as satisfactory clinical results in highly active patients. This surgical technique could be an effective treatment for grade III posterior cruciate ligament injury in highly active patients. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

National Trends of Meniscectomy and Meniscus Repair in Korea.

BACKGROUND: Meniscus surgeries are frequently performed in orthopaedics. However, their current status is not well known in many countries, including Korea. This study aimed to investigate the national trends of meniscus surgery in Korea. METHODS: Information from the national database was acquired through the Korean Health Insurance Review and Assessment Service from 2010 to 2017. All cases coded as meniscectomy or meniscus repair were included. The total number and incidence of cases of meniscus surgery per 100,000 persons were determined, and the results were stratified by age and gender. The meniscus repair ratio for the total number of meniscus surgeries was evaluated. RESULTS: The total number and incidence of meniscectomy cases were 65,752 and 137, respectively, in 2010, which increased to 74,088 and 154, respectively, in 2017. The number of meniscectomies increased by 12.67% in 8 years. The total number and incidence of meniscus repair cases were 9,055 and 18, respectively, in 2010, which increased to 14,947 and 31 in 2017. The number of meniscus repairs increased by 65.04%. The meniscus repair ratio was 12.1% in 2010, which increased to 16.8% in 2017. The highest peak was noted for patients who underwent meniscus surgeries in their 50s and 60s. Meniscectomy was performed more frequently in women (57%) than in men (43%), whereas repair was performed more frequently in men (54%) than in women (46%) over the study period. CONCLUSION: The total number and incidence of meniscus surgeries increased from 2010 to 2017; the number and incidence of meniscus repair procedures increased more rapidly than those of meniscectomy, with the peak treatment age for both surgeries being in the 50s and 60s. The current study will contribute to understanding the epidemiology of meniscus surgery, its prevention, and cost-saving measures in Korea.

Pullout fixation for medial meniscus posterior root tears: clinical results were not age-dependent, but osteoarthritis progressed.

PURPOSE: This study investigated the outcomes of pullout fixation for medial meniscus posterior root tears (MMPRTs) in patients ≤ 60 years old versus patients > 60 years old. It was hypothesized that older patients would demonstrate results comparable with those of younger patients. METHODS: Patients with pullout fixation who were followed-up for more than 5 years were included. Patients were categorized into two groups based on age (group A, ≤ 60 years; group B, > 60 years). The Lysholm score, Kellgren-Lawrence (K-L, 0/1/2/3/4) grade, and medial joint space width were evaluated retrospectively. Preoperative results were compared with the final results in each group, which were compared between groups. RESULTS: Twenty-five patients in group A (mean age, 54.7 ± 3.8 years) and 22 patients in group B (mean age, 65.6 ± 4.4 years) were recruited. The mean follow-up duration was 70.9 months. The Lysholm score (group A, 53.0 ± 9.1 to 86.0 ± 12.1, P < 0.001; group B, 51.1 ± 7.1 to 82.9 ± 9.7, P < 0.001) improved significantly. However, the joint space width (group A, 4.7 ± 1.1 to 3.9 ± 1.1 mm, P < 0.001; group B, 4.7 ± 0.9 to 3.8 ± 0.9 mm, P < 0.001) and K-L grade (group A, 3/17/5/0/0 to 0/7/11/7/0, P < 0.001; group B, 2/14/6/0/0 to 0/3/14/5/0, P < 0.001) worsened significantly. No significant differences between groups were observed in final outcomes, including Lysholm score (n.s.), K-L grade (n.s.), and joint space narrowing (n.s.). No case with operation failure that require total knee arthroplasty was not observed. CONCLUSION: MMPRT fixation did not prevent the progression of arthrosis completely. However, clinical outcomes were not age-dependent. Thus, age may not be a critical factor to consider when applying fixation. LEVEL OF EVIDENCE: Retrospective case-control study; Level of evidence, IV.

Comparison of Modified Transtibial and Outside-In Techniques in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction.

PURPOSE: To compare the bending angle of anterior cruciate ligament (ACL) graft at femoral tunnel, graft maturation, and tunnel positions and the clinical outcomes of the modified transtibial (mTT) and outside-in (OI) techniques. METHODS: Patients who met the inclusion criteria were divided into the mTT group (n = 50) and the OI group (n = 50). Using 3-dimensional computed tomography (3-D CT), tunnel placement and femoral tunnel bending angle were analyzed. The 3.0-T magnetic resonance imaging (MRI) was used to assess the graft signal intensity (indicative of maturation) with signal/noise quotient (SNQ). Graft tension and synovialization were evaluated with second-look arthroscopy in all cases. Clinical and functional tests were completed at 36 months of follow-up. RESULTS: When tunnel placements were analyzed using the quadrant method, no significant differences were found between the mTT group and the OI group. The femoral graft bending angle was reduced in the mTT group, and the total mean of SNQ values and mean SNQ values at the femoral intraosseous and proximal graft of the mTT group were significantly lower than in the OI group (P < .001), respectively. The femoral graft bending angle on the coronal and axial planes showed moderate-to-strong correlation with the SNQ values at the femoral intraosseous and proximal graft. Second-look arthroscopy revealed better synovialization in the mTT group than in the OI group (P = .040), with no significant difference in graft tension between the 2 groups (P = .328). CONCLUSIONS: Anatomic tunnel placements did not vary between the mTT group and the OI group. However, the mTT group had more benefits in femoral graft bending angle and showed higher graft maturity and better synovial coverage than the OI group, although there were no significant differences in clinical outcomes. The acute femoral graft bending angle might negatively affect the maturation of proximal graft. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Comparison of Tibiofemoral Contact Mechanics After Various Transtibial and All-Inside Fixation Techniques for Medial Meniscus Posterior Root Radial Tears in a Porcine Model.

PURPOSE: To compare tibiofemoral contact mechanics after fixation for medial meniscus posterior root radial tears (MMPRTs). METHODS: Seven fresh knees from mature pigs were used. Each knee was tested under 5 conditions: normal knee, MMPRT, pullout fixation with simple sutures, fixation with modified Mason-Allen sutures, and all-inside fixation using Fastfix 360. The peak contact pressure and contact surface area were evaluated using a capacitive sensor positioned between the meniscus and tibial plateau, under a 1,000-N compression force, at different flexion angles (0°, 30°, 60°, and 90°). RESULTS: The peak contact pressure was significantly higher in MMPRTs than in normal knees (P = .018). Although the peak contact pressure decreased significantly after fixation at all flexion angles (P = .031), it never recovered to the values noted in the normal meniscus. No difference was observed among fixation groups (P = .054). The contact surface area was significantly lower in MMPRTs than in the normal meniscus (P = .018) and increased significantly after fixation at all flexion angles (P = .018) but did not recover to within normal limits. For all flexion angles except 60°, the contact surface area was significantly higher for fixation with Mason-Allen sutures than for fixation with simple sutures or all-inside fixation (P = .027). At 90° of flexion, the contact surface area was significantly better for fixation with simple sutures than for all-inside fixation (P = .031). CONCLUSIONS: The peak contact pressure and contact surface area improved significantly after fixation, regardless of the fixation method, but did not recover to the levels noted in the normal meniscus after any type of fixation. Among the fixation methods evaluated in this time 0 study, fixation using modified Mason-Allen sutures provided a superior contact surface area compared with that noted after fixation using simple sutures or all-inside fixation, except at 60° of flexion. However, this study had insufficient power to accurately detect the differences between the outcomes of various fixation methods. CLINICAL RELEVANCE: Our results in a porcine model suggest that fixation can restore tibiofemoral contact mechanics in MMPRT and that fixation with a locking mechanism leads to superior biomechanical properties.

Survivorship Analysis and Clinical Outcomes of Transtibial Pullout Repair for Medial Meniscus Posterior Root Tears: A 5- to 10-Year Follow-up Study.

PURPOSE: This study investigated the clinical outcomes and mid- to long-term survival rates in patients undergoing transtibial pullout repair of medial meniscus posterior root tears (MMPRTs) after a minimum follow-up of 5 years. METHODS: Between 2005 and 2011, patients with MMPRTs who had been followed for at least 5 years after undergoing transtibial pullout repair were recruited. Participants were identified using medical records and information in a prospectively collected database. Clinical outcomes were assessed based on a comparison of patient preoperative Lysholm scores and their scores at the final follow-up. A Kaplan-Meier survival analysis was used to investigate the survival rates of repair procedures. Clinical failures were defined as cases requiring conversion to total knee arthroplasty (TKA) or having final Lysholm score <65 or less than their preoperative scores. RESULTS: Overall, 91 patients (mean age, 58.7 ± 9.7 years) were included: the mean follow-up duration was 84.8 ± 13.8 months. Among these patients, the mean Lysholm score improved significantly from 51.8 ± 7.9 preoperatively to 83.0 ± 11.1 at the final follow-up (P < .001). Overall, 4 patients failed due to conversion to TKA (n = 1) or having final Lysholm scores <65 or less than the preoperative scores (n = 3). The overall Kaplan-Meier probabilities of survival after repair were 99% at 5 years, 98% at 6 years, 95% at 7 years, and 92% at 8 years. CONCLUSIONS: Among patients with MMPRTs, transtibial pullout repair demonstrated a high clinical survival rate and the patients demonstrated clinical improvement, based on mid- and long-term follow-up examinations. LEVEL OF EVIDENCE: Level IV, retrospective uncontrolled case series.

Evaluation of Anterolateral Ligament Injuries and Concomitant Lesions on Magnetic Resonance Imaging After Acute Anterior Cruciate Ligament Rupture.

PURPOSE: To evaluate the prevalence and characteristics of anterolateral ligament (ALL) injuries with a ruptured acute anterior cruciate ligament (ACL) and to analyze the presence of concomitant bone contusions and meniscal lesions. METHODS: From March 2015 to March 2017, we retrospectively analyzed 378 patients who underwent primary ACL reconstructions. Using magnetic resonance imaging, we evaluated the presence of ALL injury and concomitant lesions within 3 weeks of the injury. Meniscal tears were also identified on representative arthroscopic images. RESULTS: Following the inclusion criteria, we included a total of 275 patients in this study. The mean duration from ACL rupture to magnetic resonance imaging examination was 5.0 ± 6.0 days. We visualized ALL in 98.2% of patients, of whom 64% had ALL injuries (10.9%, 4.7%, and 48.4% were complete ruptures, Segond fracture, and partial ruptures, respectively). We found that ALL injuries were most commonly found in the femoral location. The intra- and interobserver agreement on the severity of ALL injury (κ = 0.83 and 0.81, respectively) and the location of ALL injury (κ = 0.85 and 0.84, respectively) were excellent. The association between ALL injury and lateral meniscal lesions was significant (P = .03). In particular, the proportion of the lateral meniscal posterior horn radial tears was significantly larger in nonintact ALL than in intact ALL (P = .042). The correlation between the severity of ALL injury and the degree of bone contusion at lateral compartments was significant but weak (P < .001). CONCLUSIONS: We found that more than half of acute ACL ruptures have ALL injuries. The presence of ALL injury was significantly associated with the presence of lateral meniscal lesions, especially lateral meniscal posterior horn radial tears, or lateral bone contusions. Interestingly, the severity of ALL injury significantly correlated with the degree of lateral bone contusions. LEVEL OF EVIDENCE: Level III, diagnostic cross-sectional study.