Lateral Meniscus Posterior Root Research Articles

Anatomical measurement of root attachments of the menisci

To measure anatomical data of anterior and posterior root attachments of the medial and lateral menisci for reconstruction of root tears. Thirty cadaveric knee joints of human were chosen, including 16 males and 14 females, death age ranged from 35 to 68 years old with an average age of (55.6±7.8) years old. Structure of root attachments of the menisci was dissected and observed, then areas of the attachments and the distances from the centers of the attachments of each structure to specific landmarks were measured. These landmarks were medial tibial eminence apex, lateral tibial eminence apex, the anterior edge of posterior cruciate ligament (PCL), lateral margin of cartilage of medial tibial plateau, medial margin of cartilage of lateral tibial plateau. The attachment of posterior root of medial meniscus: the central point was located on posterior about (11.73±3.10) mm and lateral about (2.77±0.86) mm to the medial tibial eminence apex; anterior about (2.76±0.76) mm to the anterior edge of PCL; lateral about (3.92±0.22) mm to lateral margin of cartilage of medial tibial plateau; the area of the attachment was (31.29±5.18) mm2 . The central point of attachment of anterior root of medial meniscus was located on anterior about (25.40±5.27) mm and lateral about (3.01±0.86) mm to the medial tibial eminence apex, and the attachment area was (46.18±11.60) mm2. The attachment of posterior root of lateral meniscus: the central point was located on posterior about (4.51 ±1.35) mm and medial about (1.85±0.34) mm to lateral tibial eminence apex; anterior about (6.91± 1.11) mm to the anterior edge of PCL; medial about (3.16±0.96) mm to medial margin of cartilage of lateral tibial plateau; and the area of attachment was (44.10±6.23) mm2. The central point of attachment of anterior root of lateral meniscus was located on anterior about (12.97±2.92) mm and lateral about (1.31 ±0.22) mm to the lateral tibial eminence apex, and the attachment area was (60.84±14.98) mm2. The study quantitatively describes the area of the attachments of the anterior and posterior roots of the medial and lateral menisci as well as the relationship between central points and corresponding landmarks, which could provide some anatomical reference for clinical repair of roots injury of menisci.

Arthroscopic side-to-side repair for complete radial posterior lateral meniscus root tears

BackgroundThe aim of this study was to determine the radiographic, second-look, and functional outcomes after arthroscopic side-to-side repair for complete radial posterior lateral meniscus root tears (PLMRTs).MethodsPatients who underwent arthroscopic side-to-side repair for complete radial PLMRTs were identified. Clinical assessment consisted of symptoms (locking, catching, giving way and effusion), examinations of joint-line tenderness and McMurray test, and subjective scores of International Knee Documentation Committee (IKDC), Lysholm, and Tegner. In addition, postoperative MRI scan and second-look arthroscopy were performed to assess the healing status of the repaired meniscus.ResultsTwenty-nine patients met the inclusion criteria. The mean age was 25.41 years. The mean follow-up period was 26.68 months. During the follow-up, none of the patients had symptoms of meniscal retear, lateral joint-line tenderness or a positive McMurray test. The postoperative subjective scores of IKDC, Lysholm, and Tegner improved significantly compared to the preoperative values (P = 0.01). Postoperative MRI scan showed that 28/29 (96.6%) patients achieved meniscus healing. Twenty-two patients underwent second-look arthroscopy, among whom 19 (86.4%) patients showed complete meniscus healing and 3 (13.6%) patients showed partial healing.ConclusionArthroscopic side-to-side repair was a valuable surgical repair technique for complete radial PLMRTs, which leaded to significant improvements in both objective and subjective functional outcomes with a high rate of meniscus healing.Level of evidenceLevel IV, case series.

Lateral Meniscus Posterior Root Lesion Influences Anterior Tibial Subluxation of the Lateral Compartment in Extension After Anterior Cruciate Ligament Injury

Background: The lateral meniscus posterior root (LMPR) lesion further decreases dynamic knee stability after anterior cruciate ligament (ACL) injury owing to the loss of the “wedge effect” maintained by the posterior horn of the lateral meniscus. However, the effect of LMPR lesions on the static tibiofemoral relationship in extension after ACL injuries is not determined. Purpose: To (1) determine the effect of LMPR lesions on anterior tibial subluxation of the lateral compartment (ATSLC) in extension in patients with ACL injuries and to (2) identify the LMPR-related factors associated with excessive ATSLC in extension. Study Design: Cohort study; Level of evidence, 3. Methods: Between January 2015 and December 2017, 405 consecutive patients with diagnosed ACL injuries who underwent primary ACL reconstructions were retrospectively reviewed. Among them, 45 patients with combined ACL injuries and LMPR lesions (ACL+LMPR group) and 51 patients with isolated ACL injuries (ACL group) were identified. Values of ATSLC in extension were measured on preoperative supine magnetic resonance imaging and classified into high grade (≥6 mm) and low grade (<6 mm). The mean ATSLC in extension and the proportion of patients with high-grade ATSLC in extension were compared between the groups by univariate analysis. In the ACL+LMPR group, predictors of high-grade ATSLC in extension—including age, sex, body mass index, affected side, cause of injury, period from injury (<12 or ≥12 weeks), LMPR lesion pattern (radial tear or root avulsion), and meniscofemoral ligament integrity (intact or impaired)—were assessed by univariate analysis and multivariate logistic regression analysis. Results: The mean ATSLC in extension in the ACL+LMPR group was significantly greater than that in the ACL group (5.6 mm vs 3.1 mm; P = .001). The proportion of patients with high-grade ATSLC in extension in the ACL+LMPR group was also significantly larger than that in the ACL group (44.4% vs 15.7%; P = .002). In addition, the root avulsion (instead of radial tear) (odds ratio, 28.750; 95% CI, 2.344-352.549; P = .009) and the period from injury ≥12 weeks (odds ratio, 17.095; 95% CI, 1.207-242.101; P = .036) were determined to be the 2 independent predictors of high-grade ATSLC in extension. However, age, sex, body mass index, affected side, cause of injury, and meniscofemoral ligament integrity were not. Conclusion: After ACL injuries, concomitant LMPR lesion further increased ATSLC in extension. Chronic LMPR avulsion was associated with high-grade ATSLC in extension.

Medial Versus Lateral Meniscus Root Tears: Is There a Difference in Injury Presentation, Treatment Decisions, and Surgical Repair Outcomes?

To determine (1) the demographic characteristics as well as radiographic findings of medial versus lateral meniscal root tears at time of presentation, (2) treatment decisions and clinical outcomes of patients undergoing medial versus lateral root repair, and (3) risk factors for worse clinical and radiographic outcomes. A retrospective review was performed to identify patients with symptomatic, medial, or lateral meniscus posterior root tears with a minimum 2-year follow-up. Radiographs were graded using Kellgren-Lawrence scores. Subanalysis was performed on 62 patients who underwent root repair. Tegner, Lysholm, International Knee Documentation Committee scores, and progression to arthroplasty were analyzed in the repair groups. Patient demographics, radiographic findings, and clinical outcomes were compared between medial meniscus posterior horn root tear (MMRT) and lateral meniscus root repair (LMRT). Of the 141 root tears, 109 were MMRTs, 30 were LMRTs, and 2 patients had both. At the time of injury, patients with MMRTs had a significantly higher age (MMRT= 51.4 vs LMRT=24.6, P < .0001), body mass index (MMRT= 32.1 vs LMRT 25.8, P < .0001), Kellgren-Lawrence score (MMRT= 1.3 vs LMRT=0.6, P < .0001), and higher rate of major meniscal extrusion (MMRT= 72% vs LMRT= 20%, P < .0001). Of the 30 LMRT, 30/30 (100.0%) were treated with meniscal repair. With MMRT, 52/109 (48%) were treated nonoperatively, 27/109 (25%) with partial meniscectomy, and 30/109 (27%) with meniscal repair. Sixty-two patients underwent meniscus root repair with an average 41-month follow-up. LMRT had significantly increased International Knee Documentation Committee (LMRT= 89.5, MMRT= 80.4, P= .02) and Tegner scores (LMRT= 6.5, MMRT= 5.1, P < .05) compared with MMRT. Compared with MMRTs, LMRTs occur in younger male patients with lower body mass index, less cartilage degeneration, less extrusion on magnetic resonance imaging, and more commonly with a ligament injury. Although good to excellent clinical outcomes were attained in select patients for both medial and lateral meniscus root repair, LMRTs may have better results after repair, suggesting that differences in injury and patient characteristics may contribute to differences in these outcomes. Retrospective comparative study, Level III.

Incidence of Displaced Posterolateral Tibial Plateau and Lateral Femoral Condyle Impaction Fractures in the Setting of Primary Anterior Cruciate Ligament Tear

Background: Bone bruising of the posterolateral tibial plateau and the lateral femoral condyle sulcus terminalis has a well-established association with anterior cruciate ligament (ACL) tears. Impaction fractures of the femur and tibia may occur in these locations; however, there is a paucity of literature describing these fractures. Purpose: The primary objective was to quantify the incidence, size, and location of impaction fractures of the posterolateral tibial plateau and lateral femoral condyle in patients with primary ACL tears. The secondary objective was to investigate the association between impaction fractures and concomitant meniscal and ligamentous injuries. Study Design: Case series; Level of evidence 4. Methods: Patients with available magnetic resonance imaging (MRI) scans who were treated for primary ACL tear by a single surgeon were identified. MRI scans were reviewed with denotation of posterolateral tibial and femoral condylar contusions and displaced impaction fractures. Measurements of the lateral tibial plateau were taken in all patients with displaced lateral tibial plateau fractures and in a subset of control patients without tibial plateau fracture present to characterize the size and location of the bony lesion. Associations of impaction fractures with concomitant meniscal or ligamentous injuries were evaluated through use of chi-square testing. Results: There were 825 knees identified with available MRI scans. Lateral tibial plateau bone bruising was present in 634 knees (76.8%), and lateral femoral condyle bone bruising was present in 407 knees (49.3%). Posterolateral tibial plateau impaction fractures were present in 407 knees (49.3%), and lateral femoral condylar impaction fractures were present in 214 knees (25.9%). Patients with posterolateral tibial plateau impaction fractures were older than patients without these fractures (42.6 vs 32.7 years; P < .001), whereas patients with lateral femoral condylar impaction fractures were younger (23.8 vs 32.7 years; P < .001). There were 71 knees (8.6%) with a posterolateral tibial plateau impaction fracture with greater than 10% loss of lateral tibial plateau depth, and this group had an increased incidence of lateral meniscus posterior root tears (22.1% vs 12.0%; P = .02). Conclusion: Posterolateral tibial plateau impaction fractures occurred with a high incidence (49.3%) in patients with primary ACL tears and demonstrated an increased association with lateral meniscus posterior horn root tears as their size increased. Lateral femoral condylar impaction fractures occurred in 25.9% of patients with primary ACL tears and entailed an increased incidence of lateral meniscal tears and medial meniscal ramp lesions.

Morphologic Variants of Posterolateral Tibial Plateau Impaction Fractures in the Setting of Primary Anterior Cruciate Ligament Tear

Background: Impaction fractures of the posterolateral tibial plateau commonly occur in the setting of anterior cruciate ligament (ACL) tears, with considerable variability found in fracture size and morphologic features. Purpose: The primary objective was to characterize different morphologic variants of posterolateral tibial plateau impaction fractures. The secondary objective was to investigate the association between these impaction fracture variants and concomitant meniscal and ligamentous injuries. Study Design: Cross-sectional study; Level of evidence 3. Methods: Patients treated for primary ACL tears and having magnetic resonance imaging available were included in this study, and magnetic resonance images were reviewed with denotation of displaced posterolateral tibial impaction fractures. A classification system was created based on morphologic variants of impaction fractures; associations were evaluated through use of independent chi-square testing. Results: There were 825 knees meeting the inclusion criteria, with displaced posterolateral tibial plateau impaction fractures present in 407 knees (49.3%). We observed 3 distinct morphologic variants of lateral tibial plateau impaction fractures: (I) posterior cortical buckle not involving the articular surface; (II) posterior impaction fracture involving the articular surface, with subtypes based on (A) tibial plateau depth bone loss <10% and (B) bone loss >10%; and (III) displaced osteochondral fragment, with subtypes for (A) shear or (B) depressed fragment. Type IIIA impaction fractures were associated with an increased incidence of lateral meniscus posterior root tears (33.3% vs 12.4%; P = .009) and an increased incidence of lateral meniscal tears (83.3% vs 56.7%; P = .024) compared with all knees without type IIIA impaction fracture. An increased incidence of medial collateral ligament (MCL) tears was noted in patients with type IIIA impaction fractures compared with those who had no fracture or had another fracture type (61.1% vs 20.1%; P < .001). Type IIIB impaction fractures were associated with an increased incidence of lateral meniscal tears (80.0% vs 56.2%; P = .005). Conclusion: A high prevalence of displaced posterolateral tibial plateau impaction fractures occur in the setting of ACL tears, and they can be classified into distinct morphologic subtypes. Posterolateral tibial plateau impaction fractures with displaced depressed or shear fragments were both associated with an increased incidence of lateral meniscal tears, whereas impaction fractures with a shear fragment were associated with an increased incidence of lateral meniscus posterior root tears and MCL tears.

Incidence and Healing Rates of Meniscal Tears in Patients Undergoing Repair During the First Stage of 2-Stage Revision Anterior Cruciate Ligament Reconstruction

Background: Meniscal tears, including tears at the root attachment, have been associated with tears of the anterior cruciate ligament (ACL) in both primary and revision settings. However, there is a paucity of literature reporting the healing rates of meniscal repair during 2-stage revision ACL reconstruction (ACLR). Purpose: To evaluate the healing rates of meniscal repairs performed during 2-stage revision ACLR in ACL-deficient knees and to report the incidence of meniscus root tears in patients undergoing primary ACLR as compared with revision ACLR. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent primary and revision ACLR by a single surgeon were retrospectively identified. Revision ACLRs were grouped according to 1- or 2-stage ACLR. Meniscal tears were grouped according to laterality (medial, lateral) and location of tears. Meniscal repair technique was recorded, including transtibial or inside-out. Meniscal repair healing was assessed via second-look arthroscopy at the time of second-stage revision ACLR. Results: There were 1168 patients identified who underwent ACLR: 851 primary and 317 revision procedures. Sixty-four patients underwent meniscal repair during first-stage bone grafting in ACL-deficient knees, with an overall healing rate of 86%. The healing rates were 82.3% for meniscus root tears via the transtibial repair technique and 92.4% for meniscal peripheral tears via the inside-out repair technique. Meniscus root tears had overall incidences of 15.5% and 26.2% in primary and revision ACLRs, respectively. The incidence of lateral meniscus posterior root tears was approximately 4 times higher than of medial meniscus posterior root tears in both primary (12.2% vs 3.2%) and revision (20.5% vs 5.6%) ACLRs. Conclusion: A high incidence of meniscus root tears was found in patients undergoing revision ACLRs as compared with primary ACLRs. Meniscal repairs have a high rate of healing and success when performed during the first stage of revision ACLR in ACL-deficient knees.

Lateral meniscus posterior root tear in anterior cruciate ligament injury can be detected using MRI-specific signs in combination but not individually.

The purpose of this study was to evaluate (1) the diagnostic value of using single and multiple magnetic resonance imaging (MRI) findings for lateral meniscus posterior root tear (LMPRT) detection in anterior cruciate ligament (ACL) injury and (2) the influence of time from ACL injury to MRI assessment on LMPRT detection. Finally, we investigated the relationship between LMPRT and bone bruising. In all, 231 knees with ACL injury, 32 with LMPRT, were retrospectively assessed. Cases were evaluated for LMPRT based on the cleft, ghost, and truncated triangle signs, used individually or in combination. To assess the influence of the timing of the MRI assessment on LMPRT detection, we also evaluated the overall sensitivity, specificity, and accuracy in cases in which MRI was performed within 2weeks of injury. The number of condyles with bone bruising was assessed and then compared between patients with and without LMPRT. Although the sensitivity and specificity of the three signs individually were 34.4-65.6% and 94.0-97.0%, when at least one of these signs was positive, the sensitivity and specificity were 84.4% and 90.5%, respectively. However, the diagnostic value of each sign when MRI was performed within 2weeks of injury was lower than the overall value. There was a significant difference in the number of condyles with bone bruising between the LMPRT (3 ± 1) and non-LMPRT (2 ± 2) groups. Although the sensitivity of each sign for LMPRT was low, LMPRT could be detected adequately if these signs were used in combination. Therefore, surgeons should detect LMPRT using these three signs in combination, not individually. IV.

The association between high-grade pivot-shift and complete lateral meniscus posterior root tear after anterior cruciate ligament ruptures

Objective To investigate the association between high-grade pivot-shift and complete lateral meniscus posterior root (LMPR) tear in patients with anterior cruciate ligament (ACL) ruptures. Methods From January 2013 to December 2017, a total of 86 ACL injured patients with LMPR tears were reviewed retrospectively. There were 66 males and 20 females with an average age of 27.8±8.3 years (range 16-49 years) and an mean BMI of 25.1±3.2 kg/m2 (range 17.4-33.9 kg/m2). The average duration from injury to surgery was 33.5±79.4 weeks (range 3 days to 11 years). All patients were classified into high-grade pivot-shift group (60 patients of IKDC grade II-III) and low-grade pivot-shift group (26 patients of IKDC grade 0-I) according to the results of pivot-shift tests under anesthesia before ACL reconstructions. Predictive factors of high-grade pivot-shift were analyzed by multivariable Logistic regression, involving degree of LMPR tear, integrity of meniscofemoral ligament, width of lateral meniscal extrusion, KT-1000 arthrometer side-to-side difference, age, sex, and BMI. Results The prevalence of complete LMPR tear in high-grade pivot-shift group was higher than that in low-grade pivot-shift group. High-grade pivot-shift was associated to complete LMPR tear [OR=4.096, 95% CI(1.339, 12.371), P=0.013] and KT-1000 arthrometer side-to-side difference [OR=9.632, 95% CI (3.095, 29.975), P 0.05). Conclusion In patients with ACL ruptures, complete LMPR tear was an independent risk factor of high-grade pivot-shift, especially for patients with 12 weeks at least duration from injury to surgery. Key words: Anterior cruciate ligament; Menisci, tibial; Joint instability; Risk factors; Case-control studies

MENISCUS ROOT TEARS IN CHILDREN AND ADOLESCENTS

Background: The medial and lateral menisci function to optimize force transmission across the knee by increasing contact area between the femur and tibia, absorbing shock, and transmitting loads. Injuries to the meniscus root attachments result in extrusion of the meniscus, impaired distribution of hoop stresses, and degenerative articular wear. The purpose of this study is to describe meniscus root tears, associated injuries, and treatment in a series of pediatric patients Methods: A single-institution retrospective review was performed of consecutive pediatric patients treated for meniscus root tears from 2013 – 2017. Inclusion criteria were patients less than 19 years of age, arthroscopic evidence of a meniscus root tear, and minimum 6 months clinical follow-up. The primary outcome was surgery for revision of the meniscus repair. Results: Twenty-seven patients were identified to fit inclusion criteria. There were 15 males and 12 females with a mean age of 15.2 years (range 7 – 18 years). Basketball, soccer, and football accounted for the majority (56%) of injuries. The lateral meniscus was involved in 21 patients (78%) and the medial meniscus in 6 patients (22%). The posterior meniscus root was torn in 25 patients (93%) and anterior meniscus root in 2 patients (7%). The most common injury pattern was a lateral meniscus posterior root tear (19 patients, 70%). Associated injuries included an ACL tear (19 patients, 70%), PCL tear (6 patients, 22%), and a tear of the opposite meniscus (7 patients, 26%). Two root tears occurred in isolation, and both were of the posterior root of the medial meniscus. All patients were treated surgically with an arthroscopic transosseous root repair in addition to simultaneous treatment for their associated injuries. Mean follow-up was 14 months (range 6 – 37 months). No patients required additional surgery for their meniscus root tear. Two patients had a second surgery on the affected knee: one for revision ACL reconstruction 2 years following the primary procedure and the other for chondroplasty of the patella 2.5 years following the primary procedure. Conclusions: Meniscus root tears occur in pediatric and adolescent patients, most commonly affecting the posterior root of the lateral meniscus and occurring in association with ACL tears. The adolescent meniscus root injury pattern is unique compared to the adult population in which the medial meniscus posterior root is often injured in isolation. Inspection of the meniscus root attachments with deliberate probing to assess the meniscus roots should be a routine part of every knee arthroscopy. In our case series, transosseous root repair resulted in successful outcomes in all patients without need for any additional meniscus treatment.

Lateral Meniscus Posterior Root Tear (LMPRT): A Case Report

There is a high rate of missed lateral meniscus posterior root tear from pre operative magnetics resonance image (MRI) as reported in the study of Krych AJ.1 It was found that there was a high frequency (67%) of tears that were missed on preoperative MRI in this consecutive series. In our case report we present the case that missed lateral posterior meniscus root tear from pre operative MRI in the setting concomittant with anterior cruciate ligament (ACL) injury. Keywords: lateral meniscus posterior root tear DOI: 10.31524/bkkmedj.2019.02.016

Risk Factors for Lateral Meniscus Posterior Root Tears in the Anterior Cruciate Ligament–Injured Knee: An Epidemiological Analysis of 3956 Patients From the SANTI Study Group

Background: Lateral meniscus posterior root tears (LMPRTs) result in loss of hoop forces and significant increases in tibiofemoral contact pressures. Preoperative imaging lacks reliability; therefore, holding an appropriate index of suspicion, based on the epidemiology of and risk factors for LMPRT, may reduce the rate of missed diagnoses. Purpose: The primary objectives of this study were to evaluate the incidence of and risk factors for lateral meniscus root lesions in a large series of patients undergoing anterior cruciate ligament (ACL) reconstruction. Study Design: Case-control study; Level of evidence, 3. Methods: All patients who underwent primary or revision ACL reconstruction by a single surgeon between January 2011 and April 2018 were considered for study eligibility. From this overall population, all patients who underwent repair of an LMPRT were identified. The epidemiology of LMPRT was defined by the incidence within the study population, stratified by key demographic parameters. Potentially important risk factors for the presence of LMPRT were evaluated in multivariate logistic regression analysis. Results: A total of 3956 patients undergoing ACL reconstruction were included in the study. An LMPRT was identified and repaired in 262 patients (6.6%). Multivariate analyses demonstrated that significant risk factors for LMPRT included a contact sports injury mechanism (7.8% incidence with contact sport mechanism vs 4.5% with noncontact mechanism; odds ratio, 1.69; 95% CI, 1.266-2.285; P < .001) and the presence of a medial meniscal tear (7.9% incidence with medial meniscal tear vs 5.8% without; odds ratio, 1.532; 95% CI, 1.185-1.979; P < .001). Although the incidence of LMPRT in male patients (7.3%) was higher than in females (4.8%), this was not significant in multivariate analysis (P = .270). Patient age, revision ACL reconstruction, and a preoperative side-to-side laxity difference ≥6 mm were not significant risk factors for LMPRT. Conclusion: The incidence of LMPRT was 6.6% in a large series of patients undergoing ACL reconstruction. Participation in contact sports and the presence of a concomitant medial meniscal tear were demonstrated to be important independent risk factors. Their presence should raise the index of suspicion for this injury pattern.

Complementary Function of the Meniscofemoral Ligament and Lateral Meniscus Posterior Root to Stabilize the Lateral Meniscus Posterior Horn: A Biomechanical Study in a Porcine Knee Model.

Background:It has been demonstrated that the load distribution function of the lateral meniscus (LM) is compromised by resecting both the meniscofemoral ligament (MFL) and LM posterior root (LMPR). However, the effect of resecting these fibers on load transmission through the LM needs to be investigated.Purpose:To evaluate using a porcine knee model (1) the in situ forces of the MFL and LMPR and (2) the effect of resecting these fibers on the in situ force of the LM under a compressive load and valgus torque to the lateral knee compartment.Study Design:Controlled laboratory study.Methods:Twenty fresh-frozen porcine knees and a 6 degrees of freedom robotic system were utilized. An axial compressive load of 250 N and 5 N·m of valgus torque were applied to intact, MFL-deficient, LMPR-deficient, and MFL/LMPR-deficient knees at 30°, 60°, and 90° of flexion. The valgus angles under the applied loads were compared among the 4 states. The in situ forces of the MFL and LMPR under the applied loads were calculated under the principle of superposition. The in situ forces of the LM under the applied loads were also calculated and compared among the 4 conditions (intact, without the MFL, without LMPR, and without the MFL/LMPR).Results:The valgus angles significantly increased after resecting both the MFL and LMPR at all the flexion angles. The in situ forces of the MFL and LMPR changed reciprocally as the knee flexed. The in situ forces of the LM significantly decreased after resecting both the MFL and LMPR, although resecting only the MFL or LMPR represented no significant effect.Conclusion:The MFL and LMPR functioned complementarily as the posterior attachments of the LM against a compressive load and valgus torque to the lateral knee compartment in porcine knee joints.Clinical Relevance:If the LMPR is completely detached and needs to be repaired, the MFL should be preserved because it may provide some stability to the LM posterior horn and protect the repaired LMPR.

Surgical Technique for fixation of posterior root tears of the lateral meniscus and anterior cruciate ligament ruptures in acute lesions: Short-term clinical outcome

Background:Injuries of posterior lateral meniscus root (PLMR) are related to an acute trauma mechanism, which is commonly associated with anterior cruciate ligament (ACL) rupture. Many biomechanical studies have exposed the importance of the integrity of PLMR. There are several surgical techniques for its treatment, but is still controversial about which is the most appropriate, especially for combined injuries.Objective:To describe the clinical outcomes of patients with a surgical treatment of PLMR tear combined with ACL ruptureMethods:Prospective case series. With patients who undergone repair of PLMR tears with ACL rupture, from 2016 to 2017 in a specialized hospital in Medellín city. Clinical evaluation it was determinate with Lysholm and IKDC (International Knee Documentation Committee) scores, before and one year after the surgical procedure. The paired sample t-test was applied to compare the results of the scores.Results:Six patients with acute lesion of PLMR tear combined with ACL rupture received treatment with a variation in the transtibial fixation of the PLMR surgical technique. Statistically significant differences were found when comparing the two scores before and after surgery (p=<0.05). In addition, no additional surgical interventions were performed in the follow-up time.Conclusion:The combined surgical treatment of PLMR and ACL injuries can be performed safely. This surgical technique provided an improvement in function, pain and activity level, which may help to delay the progression of osteoarthritis of the knee.

Lateral Meniscal Posterior Root Repair With Anterior Cruciate Ligament Reconstruction Better Restores Knee Stability

Background: The effect of lateral meniscal posterior root tear and repair—commonly seen in clinical practice in the setting of anterior cruciate ligament (ACL) reconstruction—is not known. Purpose/Hypothesis: This study evaluated the effect of tear and repair of the lateral meniscal posterior root on the biomechanics of the ACL-reconstructed knee. It was hypothesized that anterior tibial translation would increase under anterior loading and simulated pivot-shift loading with the root tear of the posterior lateral meniscus, while repair of the root tear would reduce it close to the noninjured state. Study Design: Controlled laboratory study. Methods: Thirteen fresh-frozen adult human knees were tested with a robotic testing system under 2 loading conditions: (1) an 89.0-N anterior tibial load applied at full extension and 15°, 30°, 60°, and 90° of knee flexion and (2) a combined 7.0-N·m valgus and 5.0-N·m internal tibial torque (simulated pivot-shift test) applied at full extension and 15° and 30° of knee flexion. The following knee states were tested: intact knee, ACL reconstruction and intact lateral meniscus, ACL reconstruction and lateral meniscal posterior root tear, and ACL reconstruction and lateral meniscal posterior root repair. Results: In the ACL-reconstructed knee, a tear of the lateral meniscal posterior root significantly increased knee laxity under anterior loading by as much as 1 mm. The transosseous pullout suture root repair improved knee stability under anterior tibial and simulated pivot-shift loading. Root repair improved the ACL graft force closer to that of the native ACL under anterior tibial loading. Conclusion: Lateral meniscal posterior root injury further destabilizes the ACL-reconstructed knee, and root repair improves knee stability. Clinical Relevance: This study suggests a rationale for surgical repair of the lateral meniscus, which can restore stability close to that of the premeniscal injury state.

Abnormal tibial alignment is a risk factor for lateral meniscus posterior root tears in patients with anterior cruciate ligament ruptures.

The purpose of this study was to identify if abnormal tibial alignment was a risk factor for lateral meniscus posterior root tears (LMPRT) in patients with acute anterior cruciate ligament (ACL) ruptures. The medical charts of 200 patients treated for ACL ruptures between 2013 and 2016 were retrospectively reviewed and evaluated. MRI images and reports were assessed for concurrent meniscal tears. Radiographs were reviewed for tibia vara and tibial slope angles and MRI reports identifying lateral root tears were compared to intraoperative reports to determine accuracy. Multiple logistic regression models were constructed to identify potential risk factors for LMPRTs. Of the 200 patients reviewed, a total of 97 individuals with concurrent meniscal injuries were identified. In patients sustaining a concurrent meniscal injury, there was a 4% incidence of medial meniscus posterior root tears and a 10.3% incidence of LMPRTs. Patients sustaining an ACL injury with an LMPRT were found to have greater tibia vara angles (4.2 ± 1.0 vs. 2.9 ± 1.7; p = 0.024), increased tibial slopes (12.6 ± 1.5 vs. 10.7 ± 2.9; p = 0.034), and higher BMIs (27.3 ± 2.9 vs. 25.3 ± 5.9; p = 0.034) when compared to patients without meniscus tears. There was low agreement between MRI and arthroscopic findings (kappa rate = 0.54). Multiple logistic regression analysis demonstrated that a tibia vara angle > 3 was associated with a 5.2-fold increase (95% CI 0.99-27.01; p = 0.050), and a tibial slope > 12 with a 5.4-fold increase (95% CI 1.03-28.19; p = 0.046) in LMPRTs. Patients with greater tibia varus angles, increased tibial slopes, and higher BMIs were found to have an increased risk of LMPRTs when sustaining an ACL rupture. There was a low rate of agreement between MRI and arthroscopy in identifying LMPRTs. In patients with ACL ruptures who have abnormal tibial alignment or increased BMI, physicians should be watchful for lateral meniscus posterior root tears. 3.

High Rate of Missed Lateral Meniscus Posterior Root Tears on Preoperative Magnetic Resonance Imaging.

Background:Lateral meniscus posterior root tears (LMPRTs), if left untreated, can cause devastating effects to the knee, with rapid articular cartilage degeneration and loss of the meniscus as a secondary stabilizer. Detection and surgical repair of these defects have been linked to favorable outcomes, but preoperative identification of LMPRTs continues to be challenging.Purpose:To determine the rate of LMPRTs diagnosed preoperatively on magnetic resonance imaging (MRI) in a consecutive series of arthroscopically confirmed LMPRTs.Study Design:Case series; Level of evidence, 4.Methods:A retrospective cohort of 45 consecutive patients with arthroscopically confirmed LMPRTs between 2010 and 2017 were included in this study. The preoperative MRI report for each patient was evaluated and compared with intraoperative findings. Each preoperative MRI study was then reviewed by 2 fellowship-trained musculoskeletal radiologists who worked in consensus.Results:A total of 45 patients (32 males, 13 females) with arthroscopically confirmed LMPRTs and a mean age of 27 years (range, 14-54 years) were included in the study. Only 15 of 45 LMPRTs (33%) were initially diagnosed on preoperative MRI. Past or concurrent anterior cruciate ligament (ACL) reconstruction was present in 37 of 45 cases (82%). Upon retrospective review, 15 of the 30 missed LMPRTs were “clearly evident,” 12 “subtly evident,” and 3 “occult” (unavoidably missed). There were no significant differences in the rate of LMPRT diagnosis based on history of prior knee surgery, meniscus extrusion, or tearing of the meniscofemoral ligament.Conclusion:Despite improved identification of other meniscus tear patterns on MRI, a high percentage of LMPRTs were still missed. In the setting of previous ACL reconstruction, if the root cannot be confidently identified, the MRI interpretation should indicate that “the root is poorly visualized” to alert the surgeon to thoroughly evaluate this structure. The surgeon should maintain a high index of suspicion and carefully probe the posterior root of the lateral meniscus at the time of arthroscopy, especially in cases of ACL injury.

Diagnostic value of MRI for posterior root tear of medial and lateral meniscus

To explore diagnostic value of MRI on posterior root tear of medial and lateral meniscus. From January 2012 to January 2016, clinical data of 43 patients with meniscal posterior root tear confirmed by arthroscopy were retrospective analyzed, including 25 males and 18 females, aged from 27 to 69 years old with an average age of(42.5±8.3)years old;27 cases on the right side and 16 cases on the left side. MRI examinations of 43 patients with tear of posterior meniscus root confirmed by knee arthroscopies were retrospectively reviewed. MRI images were double-blinded, independently, retrospectively scored by two imaging physicians. Sensitivity, specificity and accuracy of MRI diagnosis of lateral and medial meniscus posterior root tear were calculated, and knee ligament injury and meniscal dislocation were calculated. Forty-three of 143 patients were diagnosed with meniscus posterior root tears by arthroscopy, including 19 patients with lateral tears and 24 patients with medial tears. The sensitivity, specificity and accuracy in diagnosis of posterior medial meniscus root tears for doctor A were 91.67%, 86.6% and 83.9% respectively, and for doctor B were 87.5%, 87.4% and 87.4%, 19 patients with medial meniscal protrusion and 2 patients with anterior cruciate ligament tear. The sensitivity, specificity and accuracy in diagnosis of posterior lateral meniscus root tears for doctor A were 73.7%, 79.9% and 79% respectively, and for doctor B were 78.9%, 82.3% and 82.5%, 4 patients with lateral meniscus herniation and 16 patients with cruciate ligament tear. Kappa statistics for posterior medial meniscus root tears and posterior lateral meniscus root tears were 0.84 and 0.72. MRI could effectively demonstrate imaging features of medial and lateral meniscal root tear and its accompanying signs. It could provide the basis for preoperative diagnosis of clinicians, and be worthy to be popularized.

Posterior Lateral Meniscus Root Reattachment With Suture Anchors: An Arthroscopic Technique

The posterior lateral meniscus root (PLMR) provides the circumferential tension required to stabilize the lateral meniscus. Thus, preservation of the PLMR is important to prevent an increase in tibiofemoral contact pressure, which could result in osteoarthritis. We describe an all-arthroscopic approach to the fixation of PLMR using suture anchors through associated posterolateral arthroscopic portals that result in a more favorable inclination of the anchors. Initially, the anatomical insertion site of the root on the tibial plateau is debrided, 1 to 2 anchors are placed through the posterolateral portals into the root's footprint area, and the meniscus is finally sutured from the posterolateral portals. Compression of the meniscus is achieved with bone contact. This technique achieves lateral meniscus root fixation, reducing the risk of subluxation of the meniscus and subsequent osteoarthritis.

Suture Repair of Full Radial Posterior Lateral Meniscus Tears Using a Central Midline Portal

Full radial posterior lateral meniscus root tears are frequently associated with injuries to the anterior cruciate ligament. Left unrepaired, they result in loss of the meniscus hoop stress function and can lead to overload of the lateral compartment and early degenerative changes. Arthroscopic suture repairs show successful results with long-term follow-up. However, previously described suture repair techniques have often required special instrumentation and can be technically demanding. This Technical Note describes the use of an accessory portal through the patellar tendon as a safe and easy method for repairing full posterior radial tears of the lateral meniscus.