Fast rehabilitation does not worsen clinical, radiological, and arthroscopic outcomes after medial meniscus posterior root repair: A retrospective comparative study.

Background/Objective: The main surgical treatment for medial meniscus posterior root tear (MMPRT) has shifted from meniscectomy to meniscus repair; however, there is no clear consensus regarding the optimal postoperative management strategy after MMPRT repair. This study aimed to perform a comparative analysis of patients who received conventional rehabilitation or fast rehabilitation following MMPRT repair. Methods: The current retrospective cohort study compared clinical, radiological, and arthroscopic outcomes after conventional rehabilitation (group A, January 2020 to April 2020, 24 patients) with those after fast rehabilitation (group B, May 2020 to August 2020, 24 patients) in patients who underwent pullout repair for MMPRT. Partial weight-bearing and range of motion exercises were allowed 2 weeks postoperatively in group A and 1 week postoperatively in group B. In patients with an average weight of approximately 60 kg, full weight bearing was allowed 4 weeks postoperatively in group A and 3 weeks postoperatively in group B. Results: At 12 months postoperatively, the clinical scores, including International Knee Documentation Committee and Japanese Knee Injury and Osteoarthritis Outcome Score, significantly improved in both groups (p < 0.01). Although meniscus healing was achieved in both groups, medial meniscus extrusion significantly progressed by 0.9 mm in group A and 0.8 mm in group B (p < 0.01, compared with preoperative extrusion). There were no significant differences in clinical scores, arthroscopic meniscal healing status, or medial meniscus extrusion progression on magnetic resonance images between the groups. Conclusion: A fast rehabilitation protocol can be safely implemented without compromising patient outcomes after pullout repair for MMPRT.

Accurate tibial tunnel position in transtibial pullout repair for medial meniscus posterior root tears delays the progression of medial joint space narrowing.

PURPOSE: This study aimed to evaluate the association between the progression of medial joint space (MJS) narrowing, medial meniscus extrusion (MME) and clinical scores and the tibial tunnel position in pullout repairs for medial meniscus posterior root tears (MMPRTs). METHODS: This retrospective study examined 54 patients. Changes in MJS (ΔMJS), MME (ΔMME) and clinical scores and their relationship with the tibial tunnel position were evaluated using correlation coefficients. The distance from the anatomical to technical attachment position in the tibial tunnel position was measured in the anterior and medial directions, and the direct distance was measured using the Pythagorean theorem. RESULTS: The mean ΔMJS and ΔMME were 0.6 ± 0.8 and 1.3 ± 1.3 mm, respectively, and the mean anterior, medial and direct distances were 1.4 ± 2.3, 2.2 ± 1.7 and 3.4 ± 1.7 mm, respectively. ΔMJS had a significant positive correlation with the medial (r = 0.580, p < 0.001) and direct (r = 0.559, p < 0.001) distances, while ΔMME had a significant positive correlation with direct distance (r = 0.295, p = 0.030). Several clinical scores were significantly negatively correlated with these distances. CONCLUSION: In transtibial pullout repair for MMPRTs, accurate tibial tunnel position delayed the progression of MJS narrowing and MME, leading to improved clinical outcomes. The progression of MJS narrowing was associated with the mediolateral direction of the tibial tunnel position, while the clinical scores were associated with the anteroposterior direction of the tibial tunnel position. These findings indicate the need to orient the tip of the guide in a more posterolateral direction when creating the tibial tunnel. LEVEL OF EVIDENCE: Level IV.

Meniscal healing status after medial meniscus posterior root repair negatively correlates with a midterm increase in medial meniscus extrusion.

PURPOSE: The second-look arthroscopic score of pullout repair for medial meniscus posterior root tears (MMPRTs) is associated with contemporaneous clinical scores and progression of cartilage damage. However, the relationship among these scores, midterm clinical scores and magnetic resonance imaging (MRI) evaluations is unknown. The relationship between the second-look arthroscopic score at 1 year and the clinical scores or MRI at 3 years was evaluated. METHODS: Sixty-three patients were included. Medial meniscus extrusion (MME) was evaluated preoperatively and at 3 years postoperatively. Clinical scores were evaluated preoperatively, and 1 and 3 years postoperatively. Meniscal healing status was assessed using the semiquantitative second-look arthroscopic score at 1 year postoperatively. Correlation coefficients between patient characteristics, postoperative clinical scores or second-look arthroscopic score and the change in MME (ΔMME) were evaluated. Multiple regression analysis was performed on the ΔMME to evaluate the effects of patient characteristics and second-look arthroscopic scores. RESULTS: No significant correlation was observed between patient characteristics and ΔMME. In contrast, a significant correlation was found between the second-look arthroscopic score and ΔMME (p < 0.001) and visual analogue scale pain score (p = 0.016) at 3 years postoperatively. In the subitems of the second-look arthroscopic score, width (p < 0.001) and stability (p = 0.009) scores also showed significant correlations with ΔMME. Multiple regression analysis showed a significant association between the second-look arthroscopic score and ΔMME (p = 0.001). CONCLUSIONS: The second-look arthroscopic score at 1 year postoperatively correlated with the ΔMME and clinical score at 3 years postoperatively. Second-look arthroscopic scores predict midterm meniscal function after pullout repair of MMPRTs. LEVEL OF EVIDENCE: Level IV.

Signal intensity of repaired posterior roots after transtibial pullout repair for medial meniscus posterior root tears in stable knees: Magnetic resonance imaging evaluations at 3 years postoperatively.

BACKGROUND: Only a few studies have assessed signal intensity after pullout repair for medial meniscus posterior root (MMPR) tears (MMPRTs) based on mid-term magnetic resonance imaging (MRI) evaluations. Therefore, this study aimed to assess the quantitative signal intensity of repaired posterior roots over time, up to 3 years postoperatively, and the related factors. METHODS: This study included 36 patients who underwent pullout repair for MMPRTs and MRI examinations using the same MRI system. The signal intensity of the repaired posterior roots was quantitatively evaluated using the signal-to-noise quotient (SNQ). Medial meniscus extrusion (MME), the SNQ for MMPR, and clinical scores were assessed over 3 years postoperatively. RESULTS: MME progressed over time until 3 years postoperatively, and its progression during this period was 1.61 ± 1.44 mm. The SNQ for MMPR decreased over time until 3 years postoperatively, and the change in the SNQ from 3 months to 3 years postoperatively (ΔSNQ) was 2.69 ± 1.69. All clinical scores significantly improved (p < 0.001). ΔSNQ was significantly correlated with body weight (correlation coefficient = -0.424, p = 0.010) and body mass index (correlation coefficient = -0.330, p = 0.050). However, ΔSNQ was not significantly correlated with preoperative or postoperative clinical scores. CONCLUSION: After pullout repair for MMPRTs, MME progressed to 3 years postoperatively. However, the signal intensity of the repaired posterior roots decreased, and clinical scores improved over time until 3 years postoperatively. Patient weight and body mass index were significantly correlated with the reduced signal intensity of the repaired posterior roots, suggesting that weight assessment in patients with MMPRTs is crucial. LEVEL OF EVIDENCE: IV.

Longitudinal changes in medial meniscus extrusion and clinical outcomes following pullout repair for medial meniscus posterior root tears: a 3-year evaluation.

PURPOSE: We aimed to evaluate the longitudinal changes in medial meniscus extrusion (MME) and clinical scores at multiple time points up to 3 years after pullout repair for medial meniscus posterior root tears (MMPRTs). METHODS: This retrospective case series study included 64 patients who underwent pullout repair for MMPRTs and four MRI evaluations (preoperatively and at 3 months, 1 year, and 3 years postoperatively). MME was measured during the same time points. Clinical scores were assessed four times: preoperatively and at 1, 2, and 3 years postoperatively. Additionally, a multivariate analysis was performed on the change in MME (ΔMME) from the preoperative measurement point to 3 years postoperatively. RESULTS: The ΔMME per month from the preoperative measurement point to 3 months postoperatively, from 3 months to 1 year postoperatively, and from 1 to 3 years postoperatively were 0.30, 0.05, and 0.01 mm/month, respectively. All clinical scores significantly improved 3 years postoperatively (p < 0.001). In a multiple regression analysis for ΔMME from the preoperative measurement point to 3 years postoperatively, sex significantly affected the outcome (p = 0.039). CONCLUSION: Following pullout repair for MMPRTs with well-aligned lower extremities, although MME progression could not be entirely prevented, the rate of progression decreased over time, and clinical scores improved. In particular, MME progressed markedly during the first 3 months postoperatively. Additionally, sex had a significant influence on MME progression, suggesting that males may be able to expand the indications of pullout repair for MMPRTs.

Assessing the Frequency and Effectiveness of Various Arthroscopic Treatments in the Management of Symptomatic Isolated Medial Meniscus Injuries Including Medial Meniscus Posterior Root Tear: A Retrospective Observational Cohort Study.

The use of various strategies for arthroscopic meniscal repairs to save the meniscus and prevent the progression of knee osteoarthritis has gradually increased. We investigated the frequency of various arthroscopic treatments and the short-term clinical outcomes of symptomatic isolated medial meniscus (MM) injuries. This retrospective observational study included 193 patients (197 knees) who underwent arthroscopic meniscal treatment for isolated MM injuries between January 2016 and April 2019. Arthroscopic meniscal repairs were divided into two groups: transtibial pullout repairs of MM posterior root tears (MMPRTs) and arthroscopic meniscal repairs for other types of MM injuries. MMPRT pullout repair, other meniscal repairs, and partial meniscectomy were performed in 71.0%, 16.8%, and 12.2% of the knees, respectively. The ratio of women to men and the patient age were higher in the pullout-repair group than the meniscal-repair group. The Preoperative Knee Injury and Osteoarthritis Outcome Score subscale (as an index of daily living activities) was significantly lower in the pullout-repair group than the meniscus-repair group. However, no significant differences were observed in these scores among the two groups postoperatively. Our results suggest that familiarity with the diagnosis and treatment of MMPRTs is necessary for orthopedic surgeons to manage isolated MM injuries.

Longitudinal changes in medial knee joint space narrowing after medial meniscus posterior root repair: A 2-year follow-up study.

BACKGROUND: Despite good clinical results, repair of medial meniscus (MM) posterior root tears (MMPRTs) may not completely prevent knee osteoarthritis progression. This study evaluated changes in the medial joint space (MJS) during the first and second years after repair, compared to narrowing in the contralateral knee, using fixed-flexion view (FFV) radiographs. METHODS: Fifty-four patients who underwent pull-out repair for a unilateral MMPRT were included. FFV radiographs were obtained pre-operatively and at the 1- and 2-year post-repair timepoints to evaluate changes in the MJS and Kellgren-Lawrence grade bilaterally. Clinical outcomes were also evaluated. RESULTS: The change in the MJS was greater in MMPRT knees than in contralateral knees during the first year (0.48 ± 0.80 mm vs. 0.09 ± 0.49 mm, p < 0.001), but this difference lessened in the second year (0.09 ± 0.36 mm vs. 0.07 ± 0.38 mm, p = 0.285). Kellgren-Lawrence grade progression in MMPRT knees was less in the second year. Clinical outcomes significantly improved at both 1 and 2 years post-repair than the pre-operative values (p < 0.001), with continued improvement in clinical outcomes in the second year. There was no significant correlation between patient characteristics and the change in the MJS from preoperatively to 2 years postoperatively. CONCLUSION: Pull-out repair for MMPRTs did not completely prevent MJS narrowing, but the rate of narrowing decreased in the second year (mean, 0.09 mm) compared to that in the first year (mean, 0.48 mm). MJS narrowing in the second year after MM posterior root repair was comparable to that of the contralateral knee. Clinical outcomes further improved over the second year after repair. LEVEL OF EVIDENCE: IV.

Superior outcomes of pullout repairs for medial meniscus posterior root tears in partial tear compared to complete radial tear.

PURPOSE: To reveal the outcomes of partial medial meniscus posterior root tears following transtibial pullout repair compared with the outcomes of complete radial meniscus posterior root tears. MATERIALS AND METHODS: We retrospectively evaluated 15 consecutive patients (male/female, 5/10; average age, 64.4 years) who underwent transtibial pullout repair for partial medial meniscus posterior root tears and compared their results with those of 86 consecutive patients who underwent the same surgery for complete medial meniscus posterior root tears. All patients underwent second-look arthroscopy on average 1 year postoperatively, and a semi-quantitative meniscal healing score (anteroposterior width, stability, and synovial coverage, total 10 points) was evaluated. Medial meniscus extrusion was evaluated preoperatively and at second-look arthroscopy. RESULTS: Postoperative clinical scores were not significantly different in the short term. However, second-look arthroscopy revealed a significant difference in repaired meniscal stability (partial tear; 3.3 points, complete tear; 2.3 points, p < 0.001) and total meniscal healing scores (partial tear; 8.3 points, complete tear; 7.1 points, p < 0.001). Medial meniscus extrusion progression was significantly different (partial tear; 0.4 mm, complete tear; 1.0 mm, p < 0.001). CONCLUSION: Partial medial meniscus posterior root tears showed better meniscal healing and less medial meniscus extrusion progression following pullout repair than complete medial meniscus posterior root tears.

Initial tension at suture fixation affects the suture breakage following medial meniscus posterior root repair: A retrospective cohort study.

OBJECTIVES: This study aimed to investigate whether the initial suture tension when pullout sutures are fixed affects postoperative clinical outcomes following medial meniscus posterior root repair. METHODS: The data of 48 patients who underwent transtibial pullout repair using two simple stitches (outer and inner sutures) with an additional all-inside posteromedial pullout were retrospectively investigated. The patients were sequentially divided into two groups to compare the clinical efficacy of the initial pullout tension (N) when pullout sutures were fixed: the 30 N Group (April 2019 to September 2019, 24 patients) and the 15 N group (October 2019 to February 2020, 24 patients). The rate of suture breakage (suture cutout or rupture) at the second-look arthroscopy at 1 year postoperatively and clinical outcomes at 2 years postoperatively were compared between the two groups. RESULTS: In both groups, each clinical score significantly improved at 2 years postoperatively. At the second-look arthroscopy, the rate of posteromedial suture breakage was significantly higher in the 30 N group (19 patients, 79 â€‹%) than in the 15 N group (10 patients, 42 â€‹%); the rate of outer suture breakage was also higher in the 30 N group (five patients, 21 â€‹%) than in the 15 N group (no patients). On comparing 2 years of preoperative clinical scores between the groups categorized according to posteromedial suture breakage, the pain score was significantly higher in the suture breakage group. CONCLUSIONS: The initial tension of pullout repair of the medial meniscus posterior root tear is related to suture breakages. To prevent suture breakage, 15 N is a more initially suitable condition than 30 N. LEVEL OF EVIDENCE: Level III.

Intercondylar notch width and osteophyte width impact meniscal healing and clinical outcomes following transtibial pullout repair of medial meniscus posterior root tears.

PURPOSE: This retrospective study aimed to investigate the relationship between intercondylar notch width (ICNW), osteophyte width (OW), and the healing of medial meniscus posterior root tears (MMPRTs) following arthroscopic pullout repair. METHODS: The study included 155 patients diagnosed with MMPRTs who underwent transtibial pullout repair. Meniscal healing status was evaluated on second-look arthroscopy using a previously reported meniscus healing score. Patients were divided into two groups based on this score: the high healing score (group HH, healing score ≥ 8 points) and suboptimal healing score (group SO, healing score ≤ 6 points) groups. Computed tomography scans were performed on patients 1 week postsurgery. ICNW and OW widths were measured and relatively evaluated based on their ratio to the intercondylar distance (ICD), represented as the ICNW/ICD ratio (%) and OW/ICD ratio (%), respectively. Patient-reported outcomes were assessed preoperatively and on second-look arthroscopy using the Knee injury and Osteoarthritis Outcome Score (KOOS) and visual analogue scale (VAS). RESULTS: There were no significant demographic differences between the SO and HH group (n = 35 and 120 patients, respectively). Regarding radiographic measurements, significant differences were observed in the ICNW/ICD ratio (group SO, 24.2%; group HH, 25.2%; p = 0.024), OW (group SO, 2.6 mm; group HH, 2.0 mm; p < 0.001), and OW/ICD ratio (group SO, 3.5%; group HH, 2.7%; p < 0.001). Both groups had similar preoperative clinical scores, but postoperative clinical scores, including KOOS-activities of daily living (group SO, 83.4; group HH, 88.7; p = 0.035) and VAS (group SO, 19.1; group HH, 11.3; p = 0.005), were significantly better in group HH. CONCLUSION: The study suggests that ICNW and OW may play a crucial role in MMPRT healing following arthroscopic pullout repair, as evidenced by the worse clinical outcomes associated with a narrower ICNW and wider OW. These findings highlight the potential significance of ICNW and OW assessments when evaluating meniscal repair indications. LEVEL OF EVIDENCE: Level III.

Weight loss enhances meniscal healing following transtibial pullout repair for medial meniscus posterior root tears.

PURPOSE: This study investigated the impact of weight change on the success of transtibial pullout repair for medial meniscus (MM) posterior root tears (MMPRTs). METHODS: The study included 129 patients diagnosed with MMPRTs who had undergone transtibial pullout repair. The patients were screened between July 2018 and November 2021. Patient-reported outcomes were assessed preoperatively and at 12 months postoperatively using the Knee injury and Osteoarthritis Outcome Score (KOOS). MM extrusion (MME) and ΔMME (postoperative MME - preoperative MME) were calculated preoperatively and at 12 months postoperatively using magnetic resonance imaging. RESULTS: Patients were divided into weight loss (body mass index [BMI] decrease of at least 0.5 kg/m2 after primary repair; n = 63) and weight gain (BMI increase of at least 0.5 kg/m2 ; n = 66) groups. Both groups had similar demographic variables and preoperative clinical scores; patient-reported outcomes significantly improved postoperatively. The weight loss group had significantly greater improvement in KOOS-quality of life (weight loss, 29.4 ± 23.7; weight gain, 23.9 ± 27.6; p = 0.034), lower postoperative MME (weight loss, 3.9 ± 1.7 mm; weight gain, 4.2 ± 1.2 mm; p = 0.043) and lower ΔMME (weight loss, 0.8 ± 0.8 mm; weight gain, 1.2 ± 0.9 mm; p = 0.002) than the weight gain group. Total arthroscopic healing scores (weight loss, 7.6 ± 1.0; weight gain, 7.2 ± 1.5; p = 0.048) and associated subscales, including anteroposterior bridging tissue width (weight loss, 4.0 ± 0.0; weight gain, 3.8 ± 0.7; p = 0.004) and MM posterior root stability (weight loss, 2.6 ± 0.7; weight gain, 2.4 ± 0.7; p = 0.041), significantly differed between the groups. CONCLUSIONS: Weight loss was associated with better meniscal healing and less MME progression after MMPRT repair, highlighting the significance of weight management in individuals undergoing meniscal surgery. These findings provide valuable insights into the clinical significance of weight loss in the success of transtibial pullout repair for MMPRTs. LEVEL OF EVIDENCE: Level III.

Time-Dependent Increase in Medial Meniscus Extrusion Predicts the Need for Meniscal Repair in Patients with Partial Medial Meniscus Posterior Root Tears: A Case-Control Study.

Purpose: This study aimed to compare medial meniscus extrusion (MME) in patients with partial medial meniscus posterior root tears (MMPRTs) through magnetic resonance imaging (MRI) conducted at two-time points and to determine whether patient characteristics or MME measurements differ in patients who respond to nonoperative treatment compared with those who require surgical treatment. Methods: Thirty-seven patients with partial MMPRTs underwent two MRI scans during nonoperative management or before pull-out repair. Among these, 17 patients received nonoperative management, and 20 underwent pull-out repair. Partial MMPRTs were diagnosed based on the MRI findings. MME measurements were performed on both MRI scans. Statistical and receiver operating curve (ROC) analyses were performed. Results: The duration between the two MRI scans was significantly shorter in the pull-out repair group than in the nonoperative management group. The increase in MME (ΔMME) on MRI scans was significantly greater in the pull-out repair group than in the nonoperative management group. Linear regression analysis revealed a weak correlation between the MRI interval and ΔMME in the nonoperative management group and a moderate correlation in the pull-out repair group. In the ROC construction, the cut-off value for ΔMME that requires surgical intervention was 0.41 mm, with a sensitivity and specificity of 85.0% and 52.9%, respectively. Conclusion: Patients with partial MMPRTs requiring surgical treatment had greater MME progression in a shorter time and a time-dependent increase in MME. Therefore, a ΔMME of ≥ 0.41 mm may be useful in deciding surgical intervention based on MRI retests. Level of evidence: III.

Increased quadriceps muscle strength after medial meniscus posterior root repair is associated with decreased medial meniscus extrusion progression.

BACKGROUND: This study aimed to assess quadriceps muscle strength after medial meniscus (MM) posterior root repair and determine its relationship with clinical scores and MM extrusion (MME). METHODS: Thirty patients who underwent pullout repair for MM posterior root tear and were evaluated for quadriceps muscle strength preoperatively and at 1 year postoperatively were included in this study. Quadriceps muscle strength was measured using the Locomo Scan-II instrument (ALCARE, Tokyo, Japan). MME and clinical scores (i.e., Knee Injury and Osteoarthritis Outcome Score [KOOS], International Knee Documentation Committee score, Lysholm score, Tegner score, and visual analog scale pain score) were evaluated preoperatively and at 1 year postoperatively, and second-look arthroscopy was performed at 1 year postoperatively. Wilcoxon's signed-rank test was used to compare each measure pre- and postoperatively. Pearson's correlation coefficient was used to assess the correlation with quadriceps muscle strength values. Multiple regression analysis was performed to identify factors associated with the change in MME (ΔMME). RESULTS: Second-look arthroscopy confirmed continuity of the posterior root in all patients. The quadriceps muscle strength measured at 1 year postoperatively (355.1 ± 116.2 N) indicated significant improvement relative to the quadriceps muscle strength measured preoperatively (271.9 ± 97.4 N, p < 0.001). The MME at 1 year postoperatively (4.59 ± 1.24 mm) had progressed significantly relative to the MME preoperatively (3.63 ± 1.01 mm, p < 0.001). The clinical scores at 1 year postoperatively were improved significantly relative to the scores preoperatively (p < 0.001). The postoperative quadriceps muscle strength was correlated with ΔMME (correlation coefficient = -0.398, p = 0.030), and the change in quadriceps muscle strength was correlated with the KOOS-Quality of Life (correlation coefficient = 0.430, p = 0.018). Multiple regression analysis showed that the postoperative quadriceps muscle strength had a significant effect on ΔMME even when the body mass index and time from injury to surgery were included. CONCLUSIONS: After MM posterior root repair, patients with greater quadriceps muscle strength showed less MME progression. In addition, patients with greater improvement in quadriceps muscle strength had better clinical scores; therefore, continued rehabilitation aimed at improving quadriceps muscle strength after MM posterior root repair is recommended. LEVEL OF EVIDENCE: IV.

Effectivity of the Outside-In Pie-Crusting Technique and an All-Inside Meniscal Repair Device in the Repair of Ramp Lesions.

Ramp lesions are characteristic medial meniscus injuries seen in anterior cruciate ligament-injured knees. Anterior cruciate ligament injuries combined with ramp lesions increase the amount of anterior tibial translation and tibial external rotation. Therefore, the diagnosis and treatment of ramp lesions have received increasing attention. However, ramp lesions can be difficult to diagnose on preoperative magnetic resonance imaging. Additionally, ramp lesions are difficult to observe and treat intraoperatively in the posteromedial compartment. Although good results have been reported with the use of a suture hook through the posteromedial portal in the treatment of ramp lesions, the complexity and difficulty of the technique are further problems. The outside-in pie-crusting technique is a simple procedure that can enlarge the medial compartment and facilitate the observation and repair of ramp lesions. After this technique, ramp lesions can be properly sutured, using an all-inside meniscal repair device, without damaging the surrounding cartilage. A combination of the outside-in pie-crusting technique and an all-inside meniscal repair device (with only anterior portals) is effective in the repair of ramp lesions. This Technical Note aims to report in detail the flow of a series of techniques, including our diagnostic and therapeutic methods.

Meniscus extrusion is a predisposing factor for determining arthroscopic treatments in partial medial meniscus posterior root tears.

BACKGROUND: Patients with partial medial meniscus posterior root tears (MMPRTs) sometimes require arthroscopic pullout repair because of their intolerable/repeated knee pains and continuous disturbance in gait during activities of daily living. However, the predisposing factors for future knee surgery in patients with partial MMPRTs remain unclear. We compared the findings of magnetic resonance imaging (MRI) between patients who underwent pullout repair and nonoperative management following partial MMPRTs. METHODS: Twenty-five patients who required arthroscopic repair for partial MMPRTs and 23 patients who were managed nonoperatively were evaluated during a mean follow-up period of 27.1 months. Sex, age, height, body weight, body mass index, duration from onset to initial MRI, MRI findings, and medial meniscus (MM) extrusion were compared between the two groups. Linear regression analysis was used to assess the correlation between MM extrusion and duration from onset to MRI examination. RESULTS: No significant differences were observed between the pullout repair and nonoperative management groups in terms of patient demographics and the positive ratio of MRI-based root tear signs. However, absolute MM extrusion in the pullout repair group (3.49 ± 0.82 mm) was larger than that in the nonoperative management group (2.48 ± 0.60 mm, P < 0.001). Extrusion of the MM (> 3 mm) was detected more frequently in the pullout repair group than in the nonoperative management group (P < 0.001). The odds ratio in the pullout repair and MM extrusion > 3 mm cases was 9.662. Linear regression analysis revealed a fair correlation between the duration from onset to MRI and MM extrusion only in the pullout repair group (0.462 mm/month increase in MM extrusion). CONCLUSIONS: This study demonstrated that more severe MM extrusions were observed in the pullout repair group than in the nonoperative management group. Major extrusion (> 3 mm) was also observed more in the pullout repair group than in the nonoperative group. Assessing MM extrusion and its severity can help determine a valid treatment for patients with partial MMPRTs. LEVEL OF EVIDENCE: IV, Retrospective comparative study.

Medial joint space narrowing progresses after pullout repair of medial meniscus posterior root tear.

PURPOSE: The extent to which arthropathic changes progress after medial meniscus posterior root tear (MMPRT) repair remains controversial. This retrospective study assessed medial joint space (MJS) narrowing progression after pullout repair for MMPRT and identified the correlating factors. METHODS: We included 56 patients who underwent pullout repair for MMPRT. The MJS of the bilateral knees was assessed with radiography using the fixed-flexion view. A second-look arthroscopy was performed one year post-operatively for all patients. The baseline characteristics, clinical scores, Kellgren-Lawrence (KL) grade, and medial meniscus extrusion (MME) were identified. Statistical comparisons and correlation analyses were conducted. RESULTS: The MJS narrowing width was significantly larger in MMPRT knees than in contralateral knees (0.51 ± 0.85 mm vs. 0.09 ± 0.49 mm, p < 0.001). KL grade progression was observed in 23.2% (13/56) of patients. There was a significant difference between pre- and post-operative MME values, indicating MME progression (p < 0.001). Each clinical score showed significant improvement one year post-operatively (p < 0.001). Positive correlations were found between MJS narrowing and pre-operative MJS (coefficient = 0.510, p < 0.001), rate of change in MJS (coefficient = 0.929, p < 0.001), and increase in MME (ΔMME) (coefficient = 0.506, p < 0.001). CONCLUSION: Knees that underwent pullout repair for MMPRT showed progression of MJS narrowing by 0.51 mm at one year post-operatively, although clinical scores markedly improved. Correlating factors for MJS narrowing were pre-operative MJS, rate of change in MJS, and ΔMME. Preventing MME progression is essential for preventing arthropathic changes.

The clinical and radiographic outcomes of type 2 medial meniscus posterior root tears following transtibial pullout repair.

PURPOSE: The aim of this study was to compare the clinical outcomes of different subtypes of type 2 medial meniscus posterior root tears following transtibial pullout repair. METHODS: In total, 147 patients (mean age: 66.2 ± 8.3 years) who were diagnosed with type 2 medial meniscus posterior root tears and underwent transtibial pullout repair were included. Patients were divided into 2A (n = 31), 2B (n = 90), and 2C (n = 26) groups according to tear type. Clinical outcomes were assessed pre-operatively and at second-look arthroscopy using the Knee injury and Osteoarthritis Outcome Score. The meniscal healing status was evaluated at second-look arthroscopy. Medial meniscus extrusion was calculated using magnetic resonance imaging pre-operatively and at second-look arthroscopy. RESULTS: No significant differences in pre-operative or post-operative clinical scores were observed between each subtype, although clinical scores improved post-operatively for each subtype. Significant differences were noted in the anteroposterior width of the bridging tissues at second-look arthroscopy (2A, 7.1 ± 1.2; 2B, 6.2 ± 1.7; and 2C, 6.2 ± 1.7 mm; p = 0.045); type 2A tears were the widest. There was a significant difference in post-operative medial meniscus extrusion (2A, 3.2 ± 0.9; 2B, 4.0 ± 1.2; and 2C, 4.0 ± 1.4 mm; p = 0.004) and its progression (2A, 0.7 ± 0.6; 2B, 1.2 ± 0.8; and 2C, 1.2 ± 0.8 mm; p = 0.008), and type 2A tears were the shortest. CONCLUSION: Although there was no significant difference in the post-operative clinical scores among different type 2 tears in the short term, type 2A tears showed better healing and medial meniscus extrusion progression prevention, thus indicating the usefulness of classifying tear type in estimating post-operative outcomes. LEVEL OF EVIDENCE: III.