Knot location in arthroscopic inside-out meniscal repair: Cadaveric evaluation.

BACKGROUND: The inside-out repair technique is the gold standard for treatment of meniscal tears, while some soft tissues can be hung as the sutures are tied outside the capsule. The purpose was to clarify the association between the suture site and knot location in the arthroscopic inside-out technique. METHODS: Inside-out meniscal suture was arthroscopically performed on medial and lateral menisci in twenty-three cadaveric knees, on the assumption that longitudinal tear existed. A retractor was inserted above the semi-membranous tendon and anterior to the gastrocnemius for the medial side, while the retractor was placed in the anterior space of the gastrocnemius for the lateral side. After identifying three segments (anterior, middle and posterior segments), eight sutures were inserted into the following eight areas in each knee: anterior (M1, L1) and posterior (M2, L2) areas of the middle segment, and anterior (M3, L3) and posterior (M4, L4) areas of the posterior segment. Twelve knees underwent meniscal repair on femoral side and eleven passed sutures on the tibial side, while knots were tied outside of the joint. Attentive dissection was performed to assess the relation between knot locations and the principal structures around the knee joint. RESULTS: In medial meniscal suture, most sutures for the middle portion (M1, 2) bound medial collateral ligament (MCL), while a few cases included the semi-membranous tendon for the M4 area. In lateral meniscal suture, sutures for the L1 area tied some fibers of lateral collateral ligament (LCL) in high frequency, while popliteal muscles/tendons were tied over at the L3 area. CONCLUSIONS: Most suture knots were located on MCL or capsule in medial meniscus suture, while more than half sutures passed through LCL or popliteal tendon/muscle in lateral meniscus suture. An assistant should retract LCL under direct observation and the surgeon must confirm the direction of needle for lateral meniscal repair.

Leveraging MRI characterization of longitudinal tears of the deep digital flexor tendon in horses using machine learning.

While MRI is the modality of choice for the diagnosis of longitudinal tears (LTs) of the deep digital flexor tendon (DDFT) of horses, differentiating between various grades of tears based on imaging characteristics is challenging due to overlapping imaging features. In this retrospective, exploratory, diagnostic accuracy study, a machine learning (ML) scheme was applied to link quantitative features and qualitative descriptors to leverage MRI characteristics of different grades of tearing of the DDFT of horses. A qualitative MRI characteristic scheme, combining tendon morphologic features, altered signal intensity, and synovial sheath distention, was used for LT classification with an excellent diagnostic accuracy of the high-grade tears but more limited accuracy for the detection of low-grade tears. A quantitative ML approach was followed to measure the contribution of 30 quantitative phenotypic features for characterizing and classifying tendinous tears. Among the 30 imaging features, boundary curvature represented by the standard deviation and maximum had the most significant discriminatory power (P < 0.05) between normal and abnormal tendons and could be used as an aid for classifying the different grades of LTs of DDFTs. Imaging analysis-based 3D interactive surface plot supports qualitative characterization of different grades of LTs of the DDFT through clearer visualization of the tendon in three dimensions and simple integration of two perspectives features (i.e., margin/distribution and intensity/distribution). A systematic approach combining quantitative features with qualitative analyses using ML was diagnostically beneficial in MRI characterization and in discriminating between different grades of LTs of the DDFT of horses.

Comparison of Preoperative MRI With Intraoperative Findings for Peroneal Tendon Pathologies.

Magnetic resonance imaging (MRI) is commonly used to evaluate soft tissue pathology of the foot and ankle. Prior investigations have reported limitations of this modality, however, in evaluation of pathologies related to the peroneal tendons. This article investigates the correlation of pre-operative MRI studies with intraoperative findings. Five board-certified radiologists interpreted MRIs of 80 ankles that subsequently underwent surgical procedures performed by one board-certified foot and ankle surgeon, after which comparison was made between their findings. Statistically significant disagreement was found between radiologist and surgeon findings of a normal peroneus brevis (PB), PB and peroneus longus (PL) tendinosis, PB and PL hypertrophy, PB and PL partial linear tears, PB and PL flattening, PB longitudinal split tears, and the PB attritional spectrum (combined analysis of flattening, partial linear tearing, and longitudinal split tears). These results suggest that given the disconcordance between MRI and intraoperative findings, surgeons should remain cautious in their reliance upon this imaging modality when evaluating this anatomic region.

Arthroscopic repair of horizontal cleavage meniscus tears provides good clinical outcomes in spite of poor meniscus healing.

PURPOSE: The purpose of this study was to evaluate the clinical outcomes and meniscus healing after arthroscopic repair of horizontal-cleavage meniscus tears, compared with vertical-longitudinal meniscus tears. METHODS: This was a retrospective review of a consecutive series of 52 meniscal repairs for horizontal-cleavage tears (n = 27) or vertical-longitudinal tears (n = 25); the groups were compared with respect to clinical symptoms and meniscal healing. Arthroscopic meniscal repair was performed using the inside-out technique with a marrow-stimulating technique. Clinical symptoms were evaluated using the Lysholm score and Knee injury and osteoarthritis outcome score (KOOS). Meniscus healing was evaluated by MRI. RESULTS: The mean follow-up periods were 35.4 ± 8.9 months in the horizontal-cleavage tear group and 39.8 ± 8.3 months in the vertical-longitudinal tear group. There were no significant differences in Lysholm score and KOOS, including each subscale, between the horizontal-cleavage tear- and vertical-longitudinal tear-groups at the final follow-up. At the final follow-up, MRI meniscus grades 0 and 1 were significantly more frequent in the vertical-longitudinal tear-group than in the horizontal-cleavage tear-group, while grade 3 was significantly more frequent in the horizontal-cleavage tear group than in the vertical-longitudinal tear group (p < 0.0001). CONCLUSIONS: Although meniscus healing of horizontal-cleavage tears may be poor, arthroscopic repair should be considered for horizontal-cleavage tears because it does provide good clinical outcomes. LEVEL OF EVIDENCE: IV.

A longitudinal tear in the medial meniscal body decreased the in situ meniscus force under an axial load.

PURPOSE: To clarify the effect of longitudinal tears of the medial meniscus on the in situ meniscus force and the tibiofemoral relationship under axial load. METHODS: Twenty-one intact porcine knees were mounted on a 6-degrees of freedom robotic system, and the force and three-dimensional path of the knee joints were recorded during three cycles under a 250-N axial load at 30°, 60°, 90° and 120° of knee flexion. They were divided into three groups of seven knees with longitudinal tears in the middle to the posterior segment of the medial meniscus based on the tear site: rim, outer one-third and inner one-third of the meniscal body. After creating tears, the same tests were performed. Finally, all paths were reproduced after total medial meniscectomy, and the in situ force of the medial meniscus was calculated based on the principle of superposition. RESULTS: With a longitudinal tear, the in situ force of the medial meniscus was significantly decreased at 60°, 90° and 120° of knee flexion, regardless of the tear site. The decrement was greater with a tear in the meniscal body than a tear in the rim. A longitudinal tear in the meniscal body caused a significantly greater tibial varus rotation than a tear in the rim at all flexion angles. CONCLUSION: Longitudinal tears significantly decreased the in situ force of the medial meniscus. Tears in the meniscal body caused a larger decrease of the in situ meniscus force and greater varus tibial rotation than tears in the rim.

Contact mechanics after mattress suture repair of medial meniscus vertical longitudinal tear: an in vitro study.

PURPOSE: Most studies have concentrated on the changes in contact pressure and area on the tibiofemoral joint. This study compared the contact mechanics underneath the medial meniscus of a repaired vertical longitudinal tear with that of the intact or the torn ones. METHODS: In this controlled laboratory study, a 1000 N compressive axial load was applied to eight fresh-frozen cadaveric knees at four flexion angles and four loading conditions using a custom testing apparatus attached to a material testing machine. Intact knees, knees with a medial meniscus vertical longitudinal tear, and knees after meniscal repair were tested. The peak contact pressure and area underneath the meniscus were measured using Fuji pressure-sensitive film. RESULTS: A medial meniscus vertical longitudinal tear significantly increased the contact pressure and decreased contact area underneath the meniscus compared with those at the intact meniscus under all tested biomechanical conditions, and repair of the tear can restore the contact pressure and area in most conditions. While the repaired group showed a significantly higher or similar contact pressure compared with the tear group at 90° neutral knee position and at 60°, 90° 5 N·m-external rotation and 134 N-anterior tibial translation, and 5 N·m-internal rotation at all flexion angles. The contact area corresponding to the aberrant result of the contact pressure in the repaired group was lower than in the intact meniscus group. CONCLUSIONS: The contact mechanics underneath the meniscus of the repaired medial meniscus vertical longitudinal tear were significantly improved compared with the corresponding tear conditions in most cases, while the contact pressure and area at some certain status after repair were not significantly different from those of the corresponding tear conditions.

Clinical and MRI Outcomes of Repaired Peripheral Longitudinal Tears of the Posterior Horn of the Medial Meniscus With ACL Reconstruction: Results According to Tear Size.

Background: Arthroscopic repair of longitudinal tears in the medial meniscal posterior horn (MMPH) has been reported to result in high rates of meniscal healing when performed alongside anterior cruciate ligament reconstruction (ACLR). However, studies that have focused on longitudinal tears and their impact on clinical outcomes after arthroscopic repair are insufficient. Purpose: To investigate the clinical outcome and healing status after concomitant arthroscopic ACLR and repair of MMPH peripheral longitudinal tears, with respect to the tear length. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 263 patients who underwent concurrent arthroscopic suture repair of longitudinal tears of the MMPH and ACLR were enrolled. All patients had 2-year postoperative magnetic resonance imaging (MRI) evaluations, and 61% of patients underwent a second-look arthroscopy. The exclusion criteria were partial meniscectomies and multiligament injuries. Patients were assessed pre- and postoperatively for clinical scores, amount of anterior translation, grade of pivot shift, and presence of meniscal tear extension. According to the length of longitudinal tears, patients were classified into 2 groups: (1) patients with tears that were located in the posterior compartment and (2) patients with tears that extended to the midbody of the meniscus. Binary stepwise logistic regression analysis was used to evaluate the risk factors for unhealed menisci as identified by MRI. Results: A total of 83 patients were included in this study-52 patients (group 1) had MMPH tears without tear extension and 31 patients (group 2) had MMPH tears with tear extension. There were no differences in outcomes between the groups, including the healing rate after meniscal repair (P > .05). Based on postoperative MRI scans, 67 patients (80.7%) were categorized as completely healed and 16 patients (19.3%) as unhealed. There were no significant differences between the completely healed and unhealed groups in outcomes or the rate of preoperative midbody tear extension. Higher body mass index and lower preoperative Lysholm scores were identified as risk factors for unhealed menisci. Conclusion: Overall, the rate of complete healing of MMPH tears repaired concomitantly with ACLR was 80.7% (67/83), and midbody tear extension did not affect the healing rate of the repaired meniscus. Results indicate that suture repair for unstable MMPH tears should be considered regardless of tear size.

Placement of sutures for inside-out meniscal repair: both sutures through meniscal tissue reduces displacement on cyclical loading.

PURPOSE: The inside-out meniscal repair is widely performed to preserve the function of meniscus. In this technique, the outer suture is passed through the capsule as well as the outer meniscus, while the inner suture is inserted into the meniscus. The aim of this study was to biomechanically compare the suture stability between meniscus-meniscus and meniscus-capsule suture methods for the longitudinal meniscal tear with inside-out technique. METHODS: Twenty-seven porcine knees were dissected to maintain the femur-medial capsule/meniscus-tibia complex, and the inner meniscus was cut off along the meniscus circumferential fiber with 3 mm width of the peripheral meniscus preserved. After one needle with a 2-0 polyester suture was inserted into the inner portion of the meniscus, the other needle was inserted through 1) the peripheral meniscus (Group A), 2) capsule just above the meniscus (Group B), and 3) capsule at 10 mm apart from the meniscus-capsule junction (Group C) in the inside-out manner. Then, the suture was manually tied on the capsule. The suture gap at the repair site during 300 times of cyclic loading and the ultimate failure load in the load-to-failure test were measured. The statistical significance of the data between two groups in each combination was considered by Bonferroni correction, following a one-way analysis of variance. RESULTS: In the cyclic loading test, the suture gap was 0.68 ± 0.26 mm in Group A, 1.08 ± 0.36 mm in Group B, and 1.94 ± 0.57 mm in Group C with a significant difference. In the load-to-failure test, the ultimate failure load was 59.1 ± 13.6 N in Group A, 60.0 ± 7.9 N in Group B, and 57.4 ± 4.7 N in Group C, and there was no significant difference. CONCLUSION: The stitching region in the inside-out technique for longitudinal meniscal tear affected the stability of the tear site, and stitching the mid-substance region of the meniscus provides good stability in response to cyclic tensile loading. In addition, the stitching region did not affect the ultimate failure load. CLINICAL RELEVANCE: In the inside-out meniscal repair, the outer suture should be inserted into the remaining peripheral meniscus or the capsule near the meniscus.

Isolated peripheral longitudinal tears in the anterior-middle segment of medial meniscus among young soccer players: A case series.

INTRODUCTION: There was little information about the isolated medial meniscal tears in the anterior-middle segment. This study aimed to report the infrequent cases of the isolated medial meniscal tears in the anterior-middle segment related to kicking motion among young soccer players with a short-term postoperative outcome. PRESENTATION OF CASE: In the retrospective review of the surgical records from 2000 to 2018, there were 15 cases with the corresponding tear. They were all young male soccer players with a mean age of 16.7 years (range: 10-23 years). The cause of injury was kicking motion during playing soccer in all the patients. The most frequent symptom was locking in 80% of the cases. In the arthroscopic evaluation, all the cases presented with a longitudinal (bucket-handle) tear in the anterior-middle segment in the peripheral zone with a length of 25 to 30 mm, while the posterior segment and the cruciate ligaments were intact. Meniscal repair was performed for all the cases. At one year, all the patients could return to play soccer with a pre-injury level without any symptoms. In the second-look arthroscopy at six months among four cases, all meniscal tears healed completely. DISCUSSION AND CONCLUSION: Clinicians should be aware of the possibility of isolated peripheral longitudinal tear in the anterior-middle segment of the medial meniscus, which is related to the kicking motion among young soccer players and mainly causes locking.

Outcomes More Than 2 Years After Meniscal Repair for Longitudinal Tears of the Lateral Meniscus Combined With Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Meniscal function after repair of longitudinal tears of the lateral meniscus (LM) with anterior cruciate ligament reconstruction (ACLR) has not been comprehensively investigated. PURPOSE: To evaluate not only the clinical outcomes and radiographic findings of patients who underwent repair of longitudinal tears of the LM combined with ACLR but also the healing status of the repaired meniscus and changes in chondral status with second-look arthroscopy. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Among 548 patients who underwent primary anatomic ACLR at our institution between 2010 and 2017, 39 who had concomitant longitudinal tears of the LM and underwent repair were studied. During follow-up for more than 2 years, all patients were evaluated clinically (pain, range of motion, swelling, and knee instability) and with imaging (plain radiograph and magnetic resonance imaging [MRI]), and compared with a matched control group (based on age, sex, body mass index, and follow-up period) without any concomitant injuries who underwent ACLR. Measurements on MRI were recorded preoperatively, immediately after surgery, and at final follow-up, and the change in the values over time was assessed. Of the 39 patients in each group, 24 were assessed by second-look arthroscopy with hardware removal 2 years postoperatively. RESULTS: The mean follow-up times of the study and control group were at a mean of 42.4 and 45.4 months, respectively. There were no significant differences in clinical findings, lateral joint space narrowing on radiographs, and chondral status at the lateral compartment between groups, whereas lateral and posterior meniscal extrusion on MRI progressed significantly in the study group (0.43 ± 1.0 mm vs -0.29 ± 1.1 mm, P = .003; 1.9 ± 1.9 mm vs 0.14 ± 1.1 mm, P < .0001, respectively). Second-look arthroscopy revealed complete healing in 12 patients (50%), partial healing in 9 (37.5%), and failure in 3 (12.5%) in the study group, and no new tear in the control group. CONCLUSION: The clinical and imaging outcomes after repair of longitudinal tears of the LM combined with anatomic ACLR were successful and comparable with those after isolated ACLR without any other injuries at 42 months postoperatively, although meniscal extrusion showed progression on coronal/sagittal MRI. Based on the MRI findings and the result that only half of patients achieved complete healing, meniscal function could not be fully restored even after repair. Although degenerative changes were not apparent, longer-term follow-up is needed.

The biomechanical changes of load distribution with longitudinal tears of meniscal horns on knee joint: a finite element analysis.

BACKGROUND: Meniscal horns are important structures of meniscus, and longitudinal tears of these places could significantly change the load distribution among the knee joint. Few studies concerned the stress concentrated on bones, which may induce the osteonecrosis of subchondral bone. The goal of this study was to construct a finite element (FE) model with high fidelity of the knee joint and evaluate the biomechanical changes of load distribution of components after longitudinal tears of the horns of meniscus. METHODS: Computed tomography and magnetic resonance images were used to develop the FE model, and two different kinds of simulations, the vertical and the anterior load, mimicking the static stance and slight flexion simulations, were applied after longitudinal tears of the horns of meniscus. RESULTS: Significantly elevated peak compressive and shear stress was observed on the menisci, cartilages, and subchondral bones, and enlarged meniscus extrusion was noticed. Between all the four types of longitudinal tears investigated in this study, longitudinal tears at the posterior horn of the medial meniscus were found to be the most significant. CONCLUSIONS: These findings showed that longitudinal tears of the meniscal horns lead to increased magnitude and changed distribution of stress and indicated the important role of posterior horn of medial meniscus. This may contribute to the mechanism between meniscal tears and spontaneous subchondral bone osteonecrosis.

The characteristic arthroscopic 'eyelid- turnup' sign indicated for partial-thickness longitudinal medial meniscus tear.

BACKGROUND: Medial posterior horn meniscal tear is difficult to be visualized in full view during arthroscopy and is occasionally undetected when the superior surface seems intact. OBJECTIVE: The purpose of this study is to describe a characteristic arthroscopic sign indicating the occult partial-thickness longitudinal medial meniscus tear extending only to the inferior articular surface. METHODS: This study was a retrospective analysis of available arthroscopic knee surgery between January 2016 and December 2017. The videos were studied and data was recorded for the number of cases showing the presence of 'eyelid-turnup' sign and coexisting partial-thickness medial meniscus tear. Sensitivity and positive predictive value of the sign were calculated. RESULTS: Of all the 491 videos of medial meniscal tear available for review, partial-thickness longitudinal medial meniscus was torn in 26 cases. Six out of 26 patients could be diagnosed with partial-thickness longitudinal tear under direct vision. Of the other 20 patients which could not be diagnosed under direct vision during arthroscopy until the tear was pressed by a probe, 17 patients were diagnosed by the positive 'eyelid-turnup' sign. The other 3 patients showed negative 'eyelid-turnup' sign and were then diagnosed by the hints of preoperative MRI and intra-operative exploration. The sensitivity of the sign was 85%; the positive predictive value was 89.5%. CONCLUSIONS: The 'eyelid-turnup' sign of meniscus pressed by a probe at arthroscopy is a characteristic indicator for occult inferior partial-thickness longitudinal tears of midbody and posterior horn. Early identification of this special sign may help reduce the likelihood that the occult partial-thickness longitudinal tear will be missed during arthroscopy.

The effect of a longitudinal tear of the medial meniscus on medial meniscal extrusion in anterior cruciate ligament injury patients.

PURPOSE: The purpose of this study was to investigate the effect of a longitudinal tear of the medial meniscus (MM) and its meniscal repair on MM extrusion in anterior cruciate ligament (ACL)-injured patients. The hypothesis underlying this study was that a longitudinal tear of the MM is correlated with MM extrusion, and that the extrusion would persist after ACL reconstruction with concomitant MM repair. METHODS: Forty-three ACL-injured patients with a concomitant MM longitudinal tear were included in the MM tear group. Thirty-four solely ACL-injured patients without any meniscal injuries were included in the Control group. Medial meniscus extrusion width (MEW) was measured pre-operatively and three months after surgery on magnetic resonance imaging. RESULTS: Pre-operative MEW in the MM tear group was significantly larger than that in the Control group (MM tear group: 1.5 mm, Control: 0.3 mm, P < 0.001). The MEW change in the MM tear group was significantly greater than that in the Control group three months after operation (MM tear group: 0.8 mm, Control: -0.2 mm, P < 0.001). The number of sutures required for repair was correlated with MEW both pre-operatively and postoperatively in the MM tear group (pre-operative: P = 0.005, R = 0.42, postoperative: P < 0.001, R = 0.54). CONCLUSION: Longitudinal tear of the MM was correlated with MM extrusion and the MM extrusion persisted after ACL reconstruction with concomitant MM repair in the MM tear group. The initial meniscal tear size was directly correlated with the pre-operative MEW. Therefore, meniscal extrusion after longitudinal tears of the medial meniscus should be taken into careful consideration.

Biomechanical Comparison of Parallel and Crossed Suture Repair for Longitudinal Meniscus Tears.

BACKGROUND: Longitudinal meniscus tears are commonly encountered in clinical practice. Meniscus repair devices have been previously tested and presented; however, prior studies have not evaluated repair construct designs head to head. This study compared a new-generation meniscus repair device, SpeedCinch, with a similar established device, Fast-Fix 360, and a parallel repair construct to a crossed construct. Both devices utilize self-adjusting No. 2-0 ultra-high molecular weight polyethylene (UHMWPE) and 2 polyether ether ketone (PEEK) anchors. HYPOTHESIS: Crossed suture repair constructs have higher failure loads and stiffness compared with simple parallel constructs. The newer repair device would exhibit similar performance to an established device. STUDY DESIGN: Controlled laboratory study. METHODS: Sutures were placed in an open fashion into the body and posterior horn regions of the medial and lateral menisci in 16 cadaveric knees. Evaluation of 2 repair devices and 2 repair constructs created 4 groups: 2 parallel vertical sutures created with the Fast-Fix 360 (2PFF), 2 crossed vertical sutures created with the Fast-Fix 360 (2XFF), 2 parallel vertical sutures created with the SpeedCinch (2PSC), and 2 crossed vertical sutures created with the SpeedCinch (2XSC). After open placement of the repair construct, each meniscus was explanted and tested to failure on a uniaxial material testing machine. All data were checked for normality of distribution, and 1-way analysis of variance by ranks was chosen to evaluate for statistical significance of maximum failure load and stiffness between groups. Statistical significance was defined as P < .05. RESULTS: The mean maximum failure loads ± 95% CI (range) were 89.6 ± 16.3 N (125.7-47.8 N) (2PFF), 72.1 ± 11.7 N (103.4-47.6 N) (2XFF), 71.9 ± 15.5 N (109.4-41.3 N) (2PSC), and 79.5 ± 25.4 N (119.1-30.9 N) (2XSC). Interconstruct comparison revealed no statistical difference between all 4 constructs regarding maximum failure loads (P = .49). Stiffness values were also similar, with no statistical difference on comparison (P = .28). CONCLUSION: Both devices in the current study had similar failure load and stiffness when 2 vertical or 2 crossed sutures were tested in cadaveric human menisci. CLINICAL RELEVANCE: Simple parallel vertical sutures perform similarly to crossed suture patterns at the time of implantation.