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.

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.

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.

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.

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.

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.

Does Release of the Superficial Medial Collateral Ligament Result in Clinically Harmful Effects After the Fixation of Medial Meniscus Posterior Root Tears?

PURPOSE: To investigate pain and tenderness, stress testing, clinical outcome scores, complications, and operation time at 24 months and magnetic resonance imaging (MRI) analysis at 12 months after the release of the distal attachment of the superficial medial collateral ligament (sMCL) during medial meniscus posterior root tear (MMPRT) fixation. METHODS: Patients who received MMPRT fixation with a follow-up of at least 2 years were included. During fixation, the release of the distal attachment of the sMCL on the proximal tibia was performed to improve visualization and provide sufficient working space. Pain and tenderness at the released area, manual valgus stress tests of 30° and 0° flexion (grade 0/1/2/3), and subjective instability during weight bearing were evaluated serially at postoperative 3, 6, 12, and 24+ months. The contour of detachment area was assessed using MRI 12 months postoperatively. As a subgroup analysis, tourniquet time (minutes) and final clinical scores were compared between release and nonrelease groups. RESULTS: The numbers of participants in the release and nonrelease groups were 118 and 20 patients, and their mean follow-up durations were 42.4 ± 19.3 (24-95) and 37.2 ± 7.8 (30-55) months, respectively. In the release group, percentages of patients with pain and tenderness at 3 months were 15% and 18%, respectively; however, no patients had symptoms at 12 months. In valgus stress tests (30°, 0°), 12% and 2% of patients showed grade 1 laxity at 3 months, and 7% had grade 1 laxity in only 30° flexion at the final follow-up. However, no patients had subjective valgus laxity. An intact contour was confirmed in all cases among 94 patients checked by performing follow-up MRI. Tourniquet time was significantly shorter in the release group (42.4 ± 19.3) than in the nonrelease group (58.5 ± 9.5; P < .001). Between release and nonrelease groups, Lysholm (84.4 ± 12.1, 88.1 ± 12.8; P = .117) and International Knee Documentation Committee scores (73.6 ± 11.2, 77.5 ± 11.9; P = .112) did not differ. CONCLUSIONS: The release of the distal attachment of the sMCL during fixation of MMPRT did not result in pain and tenderness, residual instability, and complication. An intact contour of the sMCL was confirmed in all cases with MRI. This procedure reduced operation time and showed similar clinical results when compared between the release and nonrelease groups. However, this study had low power to detect the difference for clinical scores between the 2 groups. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Does synovialization after anterior cruciate ligament reconstruction have a positive effect on functional performance, outcomes scores, stability and muscle strength? A 2-year follow-up study after reconstruction.

BACKGROUND: To investigate the effect of synovialization of graft following anterior cruciate ligament reconstruction (ACLR) on functional performance test (FPT) and clinical outcomes. METHODS: Eighty-four male patients who underwent second-look arthroscopy at 2-year follow-up after unilateral ACLR using hamstring autograft were analyzed retrospectively. Patients were categorized by synovial coverage into A group (42 subjects, poor synovial coverage) and B group (42 subjects, good synovial coverage). FPT results, including those of single leg hop test (cm) of the involved limb, co-contraction test (s), shuttle run test (s), and carioca test (s), were compared between groups. Clinical scores, including Lysholm score, International Knee Documentation Committee (IKDC) subjective score, and Tegner activity score; stability assessments including Lachman test, Pivot-shift test, and side-to-side differences (cm) measured using a KT-2000 arthrometer were also compared between groups. RESULTS: Based on FPT results, no difference was evident between groups. Single leg hop test results were 144.3 ± 25.5 in A group and 145.4 ± 24.7 in B group (P = 0.849). Co-contraction test results were 17.1 ± 2.9 in A group and 16.9 ± 3.6 in B group (P = 0.827). Shuttle run test results were 9.3 ± 1.9 in A group and 9.3 ± 1.9 in B group (P = 0.935). Carioca test results were 11.4 ± 2.9 in A group and 10.5 ± 2.5 in B group (P = 0.149). Clinical scores and stability assessments did not differ between groups (P > 0.05). CONCLUSIONS: Based on functional performance results, well-synovialized grafts did not yield better functional performance outcomes following ACLR compared to poorly synovialized grafts at 2-year follow-up. The same was true of clinical outcomes. Thus, the success of synovialization does not improve functional performance and clinical outcomes following ACL reconstruction in an all-male population.

Prognostic Factors in the Midterm Results of Pullout Fixation for Posterior Root Tears of the Medial Meniscus.

PURPOSE: To identify predictors of unfavorable clinical and radiologic outcomes a minimum of 5 years after pullout fixation for medial meniscus posterior root tears (MMPRTs). METHODS: In total, 40 patients who were followed for >5 years after pullout fixation in MMPRT were recruited. The mean follow-up duration was 71.1 months. Clinical outcomes, including Lysholm score and International Knee Documentation Committee (IKDC) score, and radiographic results, including Kellgren-Lawrence (K-L; 0/1/2/3/4) grade and medial joint space width, were evaluated preoperatively and at final follow-up. Preoperative prognostic factors, including age, sex, body mass index, degree of varus alignment, K-L grade, medial joint space width, meniscal extrusion, and cartilage status, by the modified Outerbridge classification (grades 1 or 2 v 3 or 4), for relatively unfavorable (fair or poor grade) Lysholm or IKDC score, and progression of K-L grade were investigated by multivariate logistic regression analysis. RESULTS: The mean Lysholm score (52.1 ± 8.8 to 83.8 ± 11.9) and IKDC score (40.1 ± 7.6 to 73.3 ± 10.9) were improved significantly (P < .001), although the loss of medial joint space width (4.8 ± 1.1 to 3.9 ± 1.1 mm) and K-L grade (6/25/9/0/0 to 0/11/20/9/0) progressed significantly (P < .001). Unfavorable prognostic factors of the Lysholm score were grade ≥3 chondral lesions (odds ratio [OR] = 5.993; P = .028) and varus mechanical alignment (OR = 1.644; P = .017), for IKDC score were grade ≥3 chondral lesions (OR = 11.146; P = .038) and older age (OR = 1.200; P = .017). Preoperative chondral lesion grade ≥3 increased the risk of K-L grade progression (OR = 11.000; P = .031). CONCLUSIONS: Clinically, modified Outerbridge classification grade ≥3 chondral lesions, varus alignment, and older age were found to predict a poor prognosis after MMPRT fixation. In terms of radiographic K-L grade progression, grade ≥3 chondral lesions were identified as a poor prognostic factor. LEVEL OF EVIDENCE: Level IV, case series.

A meta-analysis of clinical and radiographic outcomes of posterior horn medial meniscus root repairs.

PURPOSE: Although interest in medial meniscus posterior root tear (MMPRT) repair has increased, few case series have been reported. This meta-analysis aimed to examine the clinical and radiological effects of MMPRT repair by pooling pre- and post-operative data from case-series reports. METHODS: A literature search was performed using MEDLINE/PubMed, the Cochrane Central Register of Controlled Trials, and EMBASE databases. Pre- and post-operative data were pooled to investigate the effects of MMPRT repair, including the Lysholm score improvement, meniscal extrusion (mm) reduction, progression of the Kellgren-Lawrence (K-L) grade, and cartilage status according to the Outerbridge classification. Treatment effects included paired standardized mean differences (difference in the pre- and post-operative mean outcomes divided by the standard deviation) for the Lysholm score and meniscal extrusion, as well as the pooled event rates of progression of K-L grade and cartilage status. RESULTS: As treatment effects, the Lysholm score increased by as much as 3.675 (P < 0.001), whereas meniscus extrusion was not reduced (n.s.). The overall pooled event rates of progression of K-L grade and cartilage status were 10.6 and 17.3 % (P < 0.001), respectively. CONCLUSIONS: According to the current literature, MMPRT repair resulted in significant improvements in the post-operative clinical subjective scores compared with the preoperative status. However, meniscus extrusion was not reduced. Considering the occurrence of progression of K-L grade and cartilage status, it did not prevent the progression of arthrosis completely. Based on these results, repair results in favourable outcomes for MMPRT. LEVEL OF EVIDENCE: Meta-analysis, Level IV.

Comparison of Clinical and Radiologic Results Between Partial Meniscectomy and Refixation of Medial Meniscus Posterior Root Tears: A Minimum 5-Year Follow-up.

PURPOSE: To compare the clinical and radiologic results of partial meniscectomy with those of refixation in patients with medial meniscus posterior root tears (MMPRTs) at a minimum 5-year follow-up. METHODS: Between 2005 and 2009, patients with MMPRTs who had been followed up for at least 5 years after a partial meniscectomy (group M, n = 20) or pullout repair (group R, n = 37) were recruited. The mean follow-up duration was 67.5 months in group M and 72.0 months in group R. Clinical assessments, including the Lysholm score and International Knee Documentation Committee (IKDC) Subjective Knee Form score, and radiographic assessments, including the Kellgren-Lawrence (K-L) grade and medial joint space width, were evaluated preoperatively and at final follow-up. We compared the preoperative results with the final results in each group, and we compared the final results of groups M and R. Five-year survival rates were also evaluated. RESULTS: The mean Lysholm score (P = .039) and IKDC score (P = .037) improved significantly. However, the width of the medial joint space (P < .001) and K-L grade (P < .001) worsened significantly in both groups. When we compared the final results, group R had significantly better Lysholm scores (P = .002) and IKDC scores (P < .001) than group M. Group R showed less K-L grade progression (P = .005) and less medial joint space narrowing (P < .001) than group M. The rate of conversion to total knee arthroplasty was 35% in group M, whereas there was no conversion to total knee arthroplasty in group R. The 5-year survival rates in groups M and R were 75% and 100%, respectively (P < .001). CONCLUSIONS: For MMPRTs, refixation was more effective than partial meniscectomy in terms of the clinical and radiologic outcomes and survival for at least 5 years' follow-up. Refixation slowed the progression of arthritic changes compared with partial meniscectomy, although it did not prevent the progression of arthrosis completely. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Traumatic posterior root tear of the medial meniscus in patients with severe medial instability of the knee.

PURPOSE: To examine the incidence and diagnostic rate of traumatic medial meniscus posterior root tear associated with severe medial instability and to evaluate the effectiveness of pullout repair. METHODS: From 2007 to 2011, 51 patients who underwent operation due to multiple ligament injuries including medial collateral ligament rupture were reviewed retrospectively. The International Knee Documentation Committee (IKDC) subjective and Lysholm score were evaluated pre- and postoperatively. Postoperative magnetic resonance imaging (MRI) was performed, and if indicated, a second-look arthroscopic examination was conducted. RESULTS: Fourteen out of 51 patients were associated with severe medial instability. Seven patients were diagnosed with traumatic medial meniscus posterior root tear and underwent arthroscopic pullout repair. Five of them were missed at initial diagnosis using MRI. In seven patients, the mean Lysholm and IKDC subjective scores improved from 74.6 ± 10.3 and 47.6 ± 7.3 to 93.0 ± 3.7 and 91.6 ± 2.6, respectively. All showed complete healing of meniscus root on follow-up MRI and second-look arthroscopy. CONCLUSION: Medial meniscus posterior root tear may occur in severe medial instability from trauma. It is a common mistake that surgeons may not notice on the diagnosis of those injuries using MRI. Therefore, a high index of suspicion is required for the diagnosis of medial meniscus posterior root tear in this type of injuries. The traumatic medial meniscus posterior root tear could be healed successfully using arthroscopic pullout repair technique. CLINICAL RELEVANCE: The possibility of the medial meniscus posterior root tear should be considered in severe medial instability and arthroscopic pullout repair can be an effective option for treatment. LEVEL OF EVIDENCE: Case series with no comparison group, Level IV.

No correction angle loss with stable plates in open-wedge high tibial osteotomy.

PURPOSE: The aim of this study was to compare the clinical and radiological results of the wedge plate and locking plate systems in open-wedge high tibial osteotomy. METHODS: Between 2007 and 2010, the wedge plate was used as the fixation device for osteotomy to treat a total of 67 patients; from 2009 to 2010, the locking plate was used in 19 patients. Matching for gender, age, body mass index (BMI), and articular cartilage status, 19 pairs of wedge plate and locking plate cases were enrolled in a 1:1 retrospective matched-pair analysis. Clinical data were collected and scored using the visual analogue scale and the International Knee Documentation subjective score. Additionally, pre-operative, immediate post-operative, and last follow-up radiographs were obtained to assess changes in the hip-knee-ankle (H-K-A) angle and posterior tibial slope. RESULTS: No significant differences in gender, age, BMI, follow-up period, and articular cartilage status were found between the groups. Although the initial correction of the H-K-A angles, 8.9° ± 1.9° and 9.4° ± 4.2° for the wedge plate and locking plate groups, respectively, was not significantly different, a significant difference (P = 0.046) in the final correction angles, 7.2° ± 2.1° and 9.4° ± 4.4°, respectively, was found. The increase in the posterior tibial slope, 0.5° ± 2.0° and 3.2° ± 2.6°, for the wedge plate and locking plate groups, respectively, was significantly different (P = 0.010). When classified according to the correction angle, we found that when the initial correction angle exceeded 10.0°, an average correction loss of 2.9° ± 0.5° was observed in the wedge plate group, whereas an average increase in the posterior tibial slope of 5.8° ± 1.6° was evident for the locking plate group. CONCLUSIONS: At 2 years post-operatively, the final correction angles of the wedge and the locking plate groups differed significantly, and the wedge plate group had a smaller increase in the posterior tibial slope than the locking plate group. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

Clinical and radiologic outcomes after meniscus allograft transplantation at 1-year and 4-year follow-up.

PURPOSE: To assess the clinical and radiologic outcomes of meniscus allograft transplantation (MAT) with serial evaluation at 1 year and at 4 years. METHODS: Among 151 patients who received MAT between March 2006 and June 2009, we prospectively recruited the patients who had undergone clinical and radiologic examinations at 1 year after the operation. The Lysholm score, International Knee Documentation Committee score, and Knee Society Score were determined. Plain radiography was used for evaluation of osteoarthritis, and magnetic resonance imaging (MRI) was used to assess the cartilage status and meniscal extrusion. RESULTS: Thirty-nine patients with a mean age of 40 ± 9 years were recruited. The first visit was conducted at a mean of 13.6 months (range, 11 to 17 months) postoperatively, and the last visit was conducted at a mean of 50.4 months (range, 48 to 72 months) postoperatively. Of the patients, 29 were men. The lateral side was involved in 27 patients. The Lysholm knee score increased to a median value of 89 (range, 75 to 100) at the first visit and 88 (range, 76 to 100) at the second visit from a preoperative median value of 79 (range, 37 to 99), which was statistically significant according to the Kruskal-Wallis test. According to the Kellgren-Lawrence grade based on anteroposterior radiographs, 21 patients (54%) showed no arthrosis progression and the overall status of arthrosis on anteroposterior radiographs was significantly changed (P < .001). On MRI, 25 patients (64%) showed no cartilage status change and the overall status was not changed significantly (P = .178). The meniscal extrusion extent was 4.2 ± 0.4 mm at the first visit and 4.2 ± 0.6 mm at the second visit (P = .678), and the relative percentage of extrusion was 0.44 ± 0.16 and 0.51 ± 0.21, respectively (P = .059). The subgroup in which arthrosis had progressed on MRI showed a larger amount of change in the relative percentage of extrusion (P = .023). No correlation was observed between meniscal extrusion and various outcomes. CONCLUSIONS: Repeat assessment at 4 years showed that MAT showed improvement in knee function, but it had decreased over time. Considerable meniscal extrusion was observed, but it did not increase during follow-up and did not show any correlation with other outcomes. Extrusion progression showed significant correlation with arthrosis progression. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Incidence of symptomatic discoid meniscus in Korea: epidemiologic big data analysis from HIRA database.

BACKGROUND: There is a lack of evidence of the diagnosis and treatment-related epidemiological studies of symptomatic discoid meniscus. This study analyzed the national epidemiological data for discoid meniscus in South Korea. METHODS: From 2011 to 2019, data related to the diagnosis and procedure codes of discoid meniscus were obtained from the Korean Health Insurance Review and Assessment Service database. All patients encoded as discoid meniscus were included. Data were extracted and further analyzed as follows: (1) the total number and the incidence (cases per 100,000) of discoid meniscus diagnosis per year, (2) sex distribution, (3) age distribution, (4) discoid meniscus ratio (total discoid meniscus coding per total meniscus injury coding), and (5) surgical procedures after discoid meniscus injury. RESULTS: The total number of discoid meniscus diagnosed was 4576 in 2011 and increased to 6639 in 2019, representing a 45.1% increase. The incidence was 9.5 in 2011 and increased to 13.0 in 2019. Concerning sex, discoid meniscus was more common in females (55%) than in males (45%) over the study period. Regarding age, the peak age of discoid meniscus in 2011 was "under 19," whereas in 2019, the peak age was observed in the 50s. The discoid meniscus ratio range was 2.12-2.60% from 2011 to 2019. The total number of meniscectomy increased by 20% from 2000 in 2011 to 2475 in 2014. However, the total number of meniscus repairs was 318 in 2011 and increased to 502 in 2019, indicating an increase of 58%. CONCLUSIONS: The total number and incidence of symptomatic discoid as well as the discoid meniscus ratio and the incidence of total discoid meniscus repair steadily increased from 2011 to 2019. The number of meniscus repair procedures increased more rapidly than that of meniscectomy. The current study helps understand the epidemiology of symptomatic discoid meniscus, its prevention, and cost-saving measures in South Korea.

Development and validation of a new evaluation system for patients with a floor-based lifestyle: the Korean knee score.

BACKGROUND: Patients' perspectives on functioning and health have been increasingly recognized as a crucial aspect of health care, leading to the use of patient-reported instruments for outcome assessment. However, available instruments for total knee arthroplasty do not reflect the floor-based lifestyle with high knee flexion of eastern Asia. QUESTIONS/PURPOSES: We therefore (1) describe a novel patient-generated knee evaluation instrument, the Korean knee score (KKS), to reflect floor-based lifestyles with high knee flexion that included questions regarding health-related quality of life; (2) determined the reliability of the questionnaire; and (3) performed limited validation studies. METHODS: The KKS was developed by a committee of 10 experts from 10 institutes nationwide. The development procedure comprised a development phase for generation of the questionnaire and a testing phase for assessment of measurement properties: reliability, validity, and responsiveness. A total of 634 patients participated in this test survey. RESULTS: The KKS exhibited an intraclass correlation coefficient of 0.931 and internal consistency (Cronbach's α = 0.973). The absence of a ceiling or floor effect suggested content validity. The correlation coefficient with Knee Society score (knee score, function score) and Oxford knee score was 0.599, 0.690, and 0.871, respectively, suggesting construct validity. Correlation with concurrent measures of physical function from the SF-36 ranged from 0.549 to 0.719 and those of mental function from 0.407 to 0.428. Responsiveness was evident with a standardized response mean of 0.74. CONCLUSIONS: The KKS is a reliable and responsive instrument for assessing osteoarthritis. The limited validation studies suggest it is an appropriate evaluation instrument for patients with osteoarthritis and a floor-based lifestyle.

Meniscal extrusion and spontaneous osteonecrosis with root tear of medial meniscus: comparison with horizontal tear.

PURPOSE: The incidence of root tears in patients with spontaneous osteonecrosis of the knee has been studied, but the incidence of spontaneous osteonecrosis of the knee in patients with medial meniscus root tears has not. We assessed the latter incidence and evaluated the characteristics of medial meniscus root tears by comparing clinical status, the degree of osteonecrosis, and meniscal extrusion in patients with horizontal tears. METHODS: Sixty-three patients who were diagnosed with medial meniscus posterior horn tear and treated by arthroscopic surgery between March 2005 and March 2009 were evaluated retrospectively. Patients were divided into 2 groups, the root tear group (R group) and the horizontal tear group (H group). Functional scores and radiography, simple radiography, and magnetic resonance imaging were investigated. RESULTS: No significant differences in age, body mass index, and symptom duration were observed between the 2 groups. The incidence of osteonecrosis was 12 of 36 knees (33.3%) in the R group and 4 of 27 (14.8%) in the H group. The mean absolute extrusion was 4.1 ± 0.7 mm and 3.5 ± 1.4 mm in the R and H groups, respectively (P = not significant). The mean relative percentage of extrusion in the R group (46.1% ± 9.0%) was greater than that in the H group (35.3% ± 13.2%) (P = .01). The degree of osteonecrosis (ellipsoidal volume) was also greater in the R group (423.1 ± 236.7 mm(3)) than that in the H group (175.8 ± 43.6 mm(3)) (P = .03). Though not significant, the visual analog pain score had a tendency to be more severe and knee scores had a tendency to be lower in the R group than in the H group. CONCLUSIONS: Medial meniscus root tears had a greater degree of meniscal extrusion and wider osteonecrosis than horizontal tears of the posterior horn related to loss of the main function of the meniscus. LEVEL OF EVIDENCE: Level III, retrospective comparative study.