Ramp Lesions: An Unrecognized Posteromedial Instability?

Meniscotibial Ligament Repair of a Ramp Lesion of the Posterior Horn of the Medial Meniscus

The ramp area, which is the junction between the posterior horn of the medial meniscus and the synovium, prevents anterior knee translation, transmits and distributes load, and assumes some rotational stability. Ramp lesions occur in approximately 9% to 15% of patients with anterior cruciate ligament tears. We describe an all-inside repair technique with suture for a meniscotibial ligament tear-type ramp lesion of the posterior horn of the medial meniscus.

Secondary restraints in ACL reconstruction: State-of-the-art

At-risk patients continue to experience a high likelihood of graft rupture after anterior cruciate ligament (ACL) reconstruction (ACLR). This narrative review seeks to provide the reader with an evidence-based synopsis of state-of-the-art concepts related to secondary restraint lesions, and how addressing them surgically might result in improved outcomes of ACLR.

Biomechanical characteristics of the meniscocapsular junction of the posterior segment of the medial meniscus

PURPOSE

Despite extensive literature available on the mechanical properties of knee ligaments and menisci, research on the mechanical properties of the meniscus-capsular junction (MCJ) is lacking. This study aims to investigate the biomechanical behavior of the MCJ of the medial meniscus using a tensile failure test.

MATERIALS AND METHODS

Seven dissected cadaveric knees were used for biomechanical analysis. Tensile failure tests were performed using an INSTRON ElectroPuls E1000 stress system to measure stress/strain curves, maximum load at failure, elastic limit load, elongation at break, elongation at the elastic limit, and linear stiffness, were collected and analyzed.

RESULTS

All ruptures occurred at the MCJ. The MCJ displayed similar mechanical properties to knee ligaments. Average values were: maximum load at failure (63.9 ± 3.2 N), yield load (52.9 N ± 2.6 N), elongation at break (2.5 mm ± 0.3 mm), elongation at the elastic limit (1.25 mm ± 0.15 mm), strain at break (47.0% ± 3.5%), strain at yield (23.2% ± 2.3%), and stiffness (56.6 ± 9. N/mm-1).

CONCLUSION

The meniscus-capsular junction's mechanical properties are similar to other knee ligaments and may play a role in knee stability. The findings provide insights into the the behavior of the meniscus-capsular junction could have clinical implications for diagnosing and surgical treatment of meniscocapsular lesions.

Biomechanical impact of meniscal ramp lesions on knee joint contact characteristics in ACL deficient knees: a cadaveric analysis

PURPOSE

To evaluate the changes in contact characteristics of the tibiofemoral joint resulting from a meniscal ramp lesion in the medial meniscus.

METHODS

Twelve cadaveric knees (six matched pairs) were subjected to a 600 N axial load using a custom testing jig, which allowed for knee positioning at 0°, 45°, and 90° of flexion without other constraints. The knees were randomly assigned to either a ramp lesion group (n = 6) or a posterior root lesion group (n = 6). Four testing conditions were examined: (1) intact, (2) isolated ramp lesion, (3) isolated posterior root tear of the medial meniscus, and (4) combined ramp lesion and posterior root tear of the medial meniscus. Contact characteristics were evaluated using a flexible pressure sensor, the I-Scan System.

RESULTS

Peak contact pressure in isolated ramp lesions (4.15 ± 0.98 MPa, P = 0.206) showed non-significant increases compared to the intact condition (3.86 ± 1.32 MPa). Peak contact pressure in isolated posterior root tears (4.58 ± 1.70 MPa, P = 0.040) and, combined ramp and posterior root lesions (4.67 ± 1.47 MPa, P = 0.003) were significantly higher than that in the intact condition. The knee flexion position significantly affected the medial tibiofemoral joint's contact area, contact pressure, and peak contact pressure (P < 0.001 for all).

CONCLUSION

Isolated ramp lesions did not significantly impact force transmission, contact area, or contact pressure. In contrast, isolated root lesions and combined ramp and posterior root tears of the medial meniscus significantly intensified the changes in contact characteristics in the medial tibiofemoral joint compared to the intact condition.

LEVEL OF EVIDENCE

Level III.

Investigation of the anatomic risk factors in acute anterior cruciate ligament ruptures to develop ramp lesions of the medial meniscus by quantitative MRI

OBJECTIVE

To investigate the anatomic risk factors of knee in patients with acute non-contact anterior cruciate ligament (aACL) ruptures to develop ramp lesions.

METHODS

A total of 202 subjects were retrospectively divided into three groups: (1) aACL ruptures combined with ramp lesions group (n = 76); (2) isolated ACL ruptures group (n = 56) and (3) normal controls group (n = 70). Quantitative morphological parameters on MRI were measured including: diameter of medial femoral condyle (MFC), anterior-posterior length and depth of medial tibial plateau (MTP AP length and depth), lateral posterior tibial slope (LPTS) and medial posterior tibial slope (MTPS), asymmetry of LPTS and MPTS (LMPTS), lateral meniscal slope (LMS), and medial meniscal slope (MMS).

RESULTS

The MTP AP length, MTP AP length/MFC diameter ratio, MTP depth, LPTS and the asymmetry of LMPTS showed significant differences among the three groups (p < 0.001). The risk factors associated with the ramp lesions including a longer MTP AP length (OR 1.17, 95% CI 1.00-1.44, p = 0.044), increased MTP depth (OR 1.91, 95% CI 1.22-3.00, p = 0.005) and lager ratio (OR 1.11, 95% CI 1.01-1.22, p = 0.036). The highest AUC was the MTP AP length/MFC diameter ratio (0.74; 95% CI, 0.66-0.82). The combination model increased higher accuracy (0.80; 95% CI, 0.72-0.88).

CONCLUSION

Several bony anatomic characteristics of the knee, especially the morphology of medial tibia plateau, are additional risk factors for aACL ruptures to develop ramp lesions.

CRITICAL RELEVANCE STATEMENT

Predictive anatomic risk factors of the knee for patients with acute non-contact anterior cruciate ligament (aACL) ruptures to develop ramp lesions, especially the morphology of medial tibia plateau, are detectable by MRI.

KEY POINTS

Ramp lesion development can complicate aACL ruptures and requires specific treatment. Longer AP length and increased MTP depth are risk factors for concurrent ramp lesions. Identification of ramp lesions allows for the most appropriate treatment.

Posteromedial Corner Injuries of the Knee: Imaging Findings

The posteromedial corner (PMC) of the knee is an anatomical region formed by ligamentous structures (medial collateral ligament, posterior oblique ligament, oblique popliteal ligament), the semimembranosus tendon and its expansions, the posteromedial joint capsule, and the posterior horn of the medial meniscus. Injuries to the structures of the PMC frequently occur in acute knee trauma in association with other ligamentous or meniscal tears. The correct assessment of PMC injuries is crucial because the deficiency of these supporting structures can lead to anteromedial rotation instability or the failure of cruciate ligaments grafts. This article reviews the anatomy and biomechanics of the PMC to aid radiologists in identifying injuries potentially involving PMC components.

Reverse Ramp Lesion Repair in Patients With Meniscotibial Ligament Avulsion Injury: The Hidden AMRI

Lesions of the meniscocapsular junction and the meniscotibial ligament (MTL) of the posterior horn of the medial meniscus are common with knee ligamentous injuries and associated with residual rotational instability if left untreated. MTL avulsion from its tibial attachment has never been described among different types of meniscocapsular disruptions so far. Both diagnosis and treatment of such an injury can be challenging. This article describes a detailed technique and proposes an algorithm to appropriate management of this rare injury.

The Effect of Varying Sizes of Ramp Lesions in the ACL-Deficient and Reconstructed Knee: A Biomechanical Robotic Investigation

BACKGROUND

Conflicting evidence has been reported regarding the biomechanical relevance of ramp lesions (RLs) on knee kinematics. Furthermore, the influence of the defect size of the RLs on anterior tibial translation (ATT) and external rotation (ER) is currently unknown.

PURPOSE

To evaluate the influence of RL defect size on knee kinematics in anterior cruciate ligament (ACL) deficiency and after simulated ACL reconstruction (sACLR).

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight cadaveric knee specimens were tested in a 6 degrees of freedom robotic test setup. Force-controlled clinical laxity tests were performed with 200 N of axial compression in 0°, 30°, 60°, and 90° of flexion: 5 N·m internal rotation (IR)/ER torque, 134 N ATT force, and an anteromedial drawer test consisting of 134 N ATT force under 5 N·m ER torque. After determining the native knee kinematics, the ACL was cut at the tibial insertion, followed by a transosseous refixation to simulate a surgical repair or reconstruction (simulated ACL reconstruction; sACLR). An RL was sequentially created with a length of 1, 2, and 3 cm. Each state of the RL was evaluated in the ACL-deficient state and after sACLR.

RESULTS

In the ACL-deficient state, only an RL of 3 cm length resulted in a significant increase of ATT in 30° of flexion (mean difference 0.73 mm; 95% CI, 0.36-1.1 mm). After sACLR, an RL had no significant effect. When looking at ER, an RL significantly increased ER in full extension in the ACL-deficient state in 2 cm (mean difference 0.9°; 95% CI, 0.08°-1.74°) and 3 cm length (mean difference 1.9°; 95% CI, 0.57-3.25). Furthermore, a 3-cm RL significantly increased IR in 0° of flexion in the ACL-deficient state (mean difference 1.9°; 95% CI, 0.2°-3.6°). No effect of ramp lesions on rotation was found after sACLR.

CONCLUSION

RLs result in a small increase in ATT, ER, and IR in ACL-deficient knees at early flexion angles, but not after sACLR.

CLINICAL RELEVANCE

Small RLs did not change time-zero knee kinematics and may, therefore, be left untreated, especially when the ACL is reconstructed.

Efficacy of all-inside devices in reducing gap and step-off in knee extension for ramp lesion repair: A cadaveric study

PURPOSE

The aim of this study is to assess the dynamics of the tear site of meniscal ramp lesions, particularly considering knee flexion angles, and validate anchor fixation using an all-inside device.

METHODS

Eight Thiel-embalmed paired cadaveric knees with their whole bodies were used in this study. The ramp lesions were created arthroscopically, and ramp lesion dynamics were evaluated by gradually extending the knee from 90° of knee flexion. Changes in the gap and step-off (0: no step-off; 1: cross-sectional overlap exists; and 2: tibial articular surface exposed) were evaluated at 90°, 60°, 30°, and 10° of knee flexion. After dynamic evaluation, all-inside repairs of the ramp lesions using all-inside devices were conducted. Dissection was performed to confirm the position of anchor fixation.

RESULTS

As the knee was extended, the gap significantly decreased at all knee flexion angles. Similarly, the step-off grade decreased as the knee was extended, and the step-off completely disappeared in all cases when the knee was extended from 30° to 10°. The average knee flexion angle at which the gap and step-off completely disappeared was 22.5°. After suturing the ramp lesion, arthroscopic evaluation showed that the gap had disappeared and the step-off had been repaired in all cases. Anchor fixation locations were not found within the joint but were fixed to the semimembranosus tendon or its surrounding articular capsule. Overall, 31% (5/16) anchors were fixed to the attachment site of the semimembranosus tendon, whereas the remaining were fixed to the articular capsule, located peripherally to the semimembranosus tendon.

CONCLUSION

Suturing with an all-inside device for ramp lesions is a good option, and the repair in knee extension was found to be reasonable, considering the dynamics of ramp lesions in this study.

LEVEL OF EVIDENCE

Level IV.

Factors Associated With Residual Pivot Shift After ACL Reconstruction: A Quantitative Evaluation of the Pivot-Shift Test Preoperatively and at Minimum 12-Month Follow-up

Background

Postoperative residual rotatory laxity remains despite improvement in surgical techniques for anterior cruciate ligament (ACL) reconstruction (ACLR).

Purpose

To evaluate factors associated with residual pivot shift after ACLR by quantitative measurement of the pivot shift before and after surgery.

Study Design

Case-control study; Level of evidence, 3.

Methods

A total of 97 patients who underwent primary double-bundle ACLR between June 2016 and March 2021 and underwent surgery to remove staples, with at least 12 months of follow-up evaluation, were enrolled. Quantitative measurements were performed under general anesthesia immediately before ACLR (preoperatively), after temporary fixation of the ACL graft (intraoperatively), and immediately before staple removal (postoperatively). The laxity of pivot shift was assessed using inertial sensors to measure acceleration and external rotational angular velocity (ERAV). Descriptive data were assessed for associations with postoperative acceleration and ERAV in a univariate analysis. A multiple linear regression analysis was performed to identify factors associated with postoperative acceleration and ERAV.

Results

Anterior tibial translation, acceleration, and ERAV increased from intra- to postoperatively (P < .05). Factors significantly associated with postoperative acceleration were age (β = -0.238; P = .021), lateral posterior tibial slope (PTS) (β = 0.194; P = .048), and preoperative acceleration (β = 0.261; P = .008). Factors significantly affecting postoperative ERAV were age (β = -0.222; P = .029), ramp lesions (β = 0.212; P = .027), and preoperative ERAV (β = 0.323; P = .001).

Conclusion

Greater preoperative laxity in the pivot shift was the factor having the most significant association with residual pivot shift after ACLR using quantitative measurements under general anesthesia. Younger age, higher lateral PTS, and concomitant ramp lesions were significant predictors of residual pivot shift. These findings can help pre- and intraoperative decision-making regarding whether an anterolateral structure augmentation should be added.

Increased Intra-Articular Internal Tibial Rotation Is Associated With Unstable Medial Meniscus Ramp Lesions in ACL-Injured Athletes: An MRI Matched-Pair Comparative Study

Purpose

To analyze internal tibial rotation through magnetic resonance imaging (MRI) of patients with anterior cruciate ligament (ACL) injuries with and without an unstable medial meniscal ramp lesion (MMRL).

Methods

Retrospective analysis of prospectively data was performed to include all consecutive patients who underwent primary ACL reconstruction (ACLR) between January 2022 and June 2022. Two groups, ACLR + unstable MMRL and ACLR without MMRL, were constituted. Propensity score matching analysis was used to limit selection bias. The angle between surgical epicondylar axes (SEAs) and the tangent line of the posterior tibial condyles (PTCs) was measured to analyze the rotational alignment between distal femur and proximal tibia. MMRLs were defined unstable if they were ≥1 cm, if the lesions extend beyond the lower pole of the femoral condyle, and/or if there was displacement into the medial compartment by anterior probing.

Results

Twenty-eight propensity-matched pairs were included. The ACLR + unstable MMRL presented a significantly greater internal rotation of the tibia compared to ACLR without MMRL (P < .001). An internal tibial rotation was associated with unstable ramp lesions in ACL-injured patients (odds ratio [OR], 0.36; 95% CI, 0.25-0.41; P < .0001). If SEA-PTC was 0°, the sensitivity and specificity of the SEA-PTC angle to detect unstable MMRL were respectively 100% (95% CI, 85%-100%) and 18% (95% CI, 8%-36%). Otherwise, if SEA-PTC angle was -10°, the sensitivity and specificity of the SEA-PTC angle to detect unstable MMRL were respectively 43% (95% CI, 27%-61%) and 96% (95% CI, 81%-100%). Bone edema of the posterior medial tibial plateau was significantly associated with unstable ramp lesions (OR, 1.58; 95% CI, 1.21-2.06; P = .029).

Conclusions

Unstable MMRL concomitant to an ACL rupture was associated with an increased tibial internal rotation.

Level of Evidence

Level III, retrospective comparative trial.

Editorial Commentary: Don't Neglect the Medial Side of the Knee in Patients With Anterior Cruciate Ligament Injury

The medial collateral ligament (MCL) of the knee, as well as the posteromedial complex (including the posterior oblique ligament [POL] and ramp lesions of the meniscus) is often considered the "neglected" ligament or corner because of the belief that these anatomic structures have enormous regenerative potential and therefore hardly ever need surgical treatment. In patients with anterior ligament cruciate (ACL) tears, the overall combined prevalence of MCL (superficial [sMCL] and deep [dMCL]) and isolated dMCL injuries is high (16.5% + 24.8% = 41.3%). In terms of the POL, with a restraint to both internal tibial rotation and valgus rotation during extension, I have some doubts regarding its role in anteromedial instability (AMRI). In fact, AMRI of the knee is caused mainly by injury to both the ACL and the MCLs, resulting in coupled anterior tibial translation and external rotation, causing the medial tibial plateau to subluxate anteriorly. The sMCL provides the most substantial restraint, and the dMCL and POL play more minor roles. Finally, in ACL-deficient knees, ramp lesions are prevalent (9.3%-24.0%), and failing to identify and treat these lesions results in knee instability. In my experience, all unstable ramp lesions should be repaired. In ACL-deficient knees in patients with a tibial slope >5°, an occult ramp lesion should be strongly suspected. In summary, the medial compartment of the knee is complex and encompasses many structures (MCL, POL, ramp, tibial slope), and I believe that we will increasingly move toward individualized treatment.

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.

Upsurge in publications on ramp lesions of the meniscus: A bibliometric study

PURPOSE

The purpose of this study was to analyze the trends in publications on ramp lesions of the meniscus in the current literature. We hypothesized that publications on ramp lesions have increased rapidly in recent years due to increased knowledge of both clinical and radiological pathology.

METHODS

A Scopus search performed on 21/01/23 retrieved 171 documents. A similar search strategy was employed to carry out a search for ramp lesions on PubMed with no time filters and only English articles. The articles were downloaded into Excel software, and citations for PubMed articles were determined from the iCite website. Analysis was performed using Excel. Using Orange software, data mining was performed from the titles of all articles.

RESULTS

There are a total of 126 publications from 2011 to 2022 with a total of 1778 citations in PubMed. Of all publications, 72% were published in the last 3 years, from 2020 to 2022, indicating an exponential increase in interest in this subject in recent years. Similarly, 62% of the citations were aggregated by the years 2017-2020, both years included. When the journals were analyzed according to the number of citations, the American Journal of Sports Medicine (AJSM) topped with 822 citations (46% of all citations) and 25 publications, followed by Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA) with 27 articles and 388 citations (22% of all citations). When analyzed by citations per publication for different types of studies, randomized clinical trials (RCTs) were the most cited, with 32 citations per publication, followed by basic science articles with 31.5. Most of the basic science articles were cadaver studies examining anatomy, technique, and biomechanics. Technical notes were the third most cited at 18.64 per publication. While the USA is the country that leads publications, France is in a significant second position contributing to research on this topic, followed by Germany and Luxembourg.

CONCLUSIONS

Global trend analysis suggests that ramp lesion research has significantly increased and that the number of papers on the topic is steadily increasing. We found that the publications and citations presented a rising trend, the majority of the highly cited papers were contributed by a few centers, and the most cited were randomized clinical trials and basic science studies. The long-term outcomes of conservatively and surgically treated ramp lesions have attracted the most research interest.

Meniscus tears treatment: The good, the bad and the ugly-patterns classification and practical guide

Over the years, several studies demonstrated the crucial role of knee menisci in joint biomechanics. As a result, save the meniscus has become the new imperative nowadays, and more and more studies addressed this topic. The huge amount of data on this topic may create confusion in those who want to approach this surgery. The aim of this review is to provide a practical guide for treatment of meniscus tears, including an overview of technical aspects, outcomes in the literature and personal tips. Taking inspiration from a famous movie directed by Sergio Leone in 1966, the authors classified meniscus tears in three categories: The good, the bad and the ugly lesions. The inclusion in each group was determined by the lesion pattern, its biomechanical effects on knee joint, the technical challenge, and prognosis. This classification is not intended to substitute the currently proposed classifications on meniscus tears but aims at offering a reader-friendly narrative review of an otherwise difficult topic. Furthermore, the authors provide a concise premise to deal with some aspects of menisci phylogeny, anatomy and biomechanics.

Suture Hook Versus All-Inside Repair for Longitudinal Tears of the Posterior Horn of the Medial Meniscus Concomitant to Anterior Cruciate Ligament Reconstruction: A Matched-Pair Analysis From the SANTI Study Group

BACKGROUND

Secondary meniscectomy rates after repair of longitudinal tears of the posterior horn of the medial meniscus (PHMM) performed concomitantly with anterior cruciate ligament reconstruction (ACLR) are reported to be as high as 25% with an all inside repair technique. Posteromedial portal suture hook repair is an emerging technique; however, it is unknown whether it confers a significantly reduced secondary meniscectomy rate compared with the current gold standard.

PURPOSE/HYPOTHESIS

The primary objective of this study was to compare the secondary meniscectomy rates of suture hook repair and all inside repair for longitudinal tears of the PHMM performed concomitant to ACLR. The secondary outcome was to determine the risk factors associated with the failure of the repair. It was hypothesized that repair with an all inside device would be associated with higher secondary meniscectomy rates when compared with suture hook repair and that concomitant anterolateral ligament reconstruction (ALLR) would confer improved meniscal repair survivorship.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients with longitudinal tears of the PHMM who underwent meniscal repair during primary ACLR between January 2011 and December 2015 at our institution were eligible for the study. Patients undergoing suture hook repair were propensity matched in a 1:1 ratio to patients who underwent all inside repair. At the end of the study period, secondary meniscectomy rates were determined.

RESULTS

The study population comprised 237 matched pairs. The mean follow up was 97.7 ± 17.3 months. Patients who underwent an all inside repair had a >2-fold higher failure rate compared with patients who underwent suture hook repair through a posteromedial portal (31.2% vs 15.6%; P = .0003). Patients in the suture hook repair group undergoing additional ALLR demonstrated a >3-fold higher meniscal repair survival rate compared with all other subgroups (P = .0014). This association was not seen in the all inside repair group. The only statistically significant risk factor for meniscal repair failure was the suture repair technique (hazard ratio, 2.133 [95% CI, 1.383-3.292]; P = .0008).

CONCLUSION

Suture hook repair through a posteromedial portal is associated with a significantly lower secondary meniscectomy rate when compared with the all inside meniscal repair of longitudinal tears of the PHMM performed at the time of ACLR. Furthermore, patients in the suture hook repair group who underwent an additional ALLR had a significantly better meniscal repair survivorship compared with all other subgroups.

Meniscal Tear Management Associated with ACL Reconstruction

Meniscal lesions often occur in association with anterior cruciate ligament (ACL) tears at the moment of the injury or, secondarily, as a consequence of knee instability. Both ACL and meniscus lesions are associated with a higher risk of osteoarthritis. Adequate treatment of these lesions reduces the rate of degenerative changes in the affected knee. Meniscal tears should be addressed concomitantly with ACL reconstruction and the treatment must be oriented towards preserving the meniscal tissue anytime this is possible. Several options for approaching a meniscus tear are available. The meniscal suture should always be considered, and, if possible, meniscectomy should be the last choice. “Masterly neglect” is a valuable option in selected cases.

The crevice sign: a new indicator of meniscal instability in ACL reconstructions

PURPOSE

Meniscus preservation is key in knee surgery. The newly documented crevice sign indicates instability of the medial meniscus in ACL-deficient knees. Once the sign is visualised, it is imperative that the stability of the medial meniscus is assessed and potentially treated. It was hypothesized that there would be a strong correlation between the presence of an unstable medial meniscal tear in patients with the crevice sign in ACL-deficient knees.

METHODS

This was a multicenter prospective study carried out to evaluate the incidence of medial meniscal tears in patients with ACL-deficient knees and their correlation with a crevice sign. All patients (128) who had undergone ACL reconstruction between May 2020 and November 2020 were assessed arthroscopically for meniscal stability and divided in to two groups: stable (n = 84) and unstable (n = 44). Thereafter, the presence of the crevice sign was determined in each case.

RESULTS

The populations were comparable in terms of sex and age (Table 1). Fisher's exact test showed a significant association between the presence of the crevice sign and the instability of the medial meniscus (p < 0.001). Descriptive statistics suggest that the presence of crevice sign was associated more frequently to MM instability (38.6% vs 1.2%; p < 0.001). The specificity of this test was 98.8% and its sensitivity was 38.6%. The positive predictive value (PPV) was 94.4% and the negative predictive value (NPV) was 75.5%. Table 1 Descriptions and comparisons of internal meniscus instability of patients by presence of crevice sign Internal meniscus instability (N = 44) Internal meniscus stability (N = 84) Total (N = 128) Gender  N 44 84 128   Male 33 (75.0) 58 (69.0) 91 (71.1)   Female 11 (25.0) 26 (31.0) 37 (28.9) Fisher's exact test (n.s.) Age (years)  N 44 84 128   Mean (ET) 28.6 (9.4) 30.1 (10.2) 29.6 (9.9)   Median (IIQ) 26.5 (22.0;34.5) 27.0 (22.5;37.0) 27.0 (22.0;36.0)   [Min-Max] [14-54] [14-52] [14-54] Wilcoxon test bilateral (n.s.) Crevice sign  N 44 84 128   Absent 27 (61.4) 83 (98.8) 110 (85.9)   Present 17 (38.6) 1 (1.2) 18 (14.1) Fisher's exact test p < 0.001 CONCLUSION: The hypothesis was confirmed since medial meniscal instability was strongly correlated with the existence of the crevice sign and showed high specificity and PPV.

LEVEL OF EVIDENCE

III.

Cam Impingement of the Knee: Arthroscopic Correction of Posteromedial Tibiofemoral Incongruence

One of the anatomic variations observable within the knee joint is a reduction in the posterior curvature of the femoral metaphysis proximal to the medial femoral condyle. This curvature is usually concave enough to fit the posterior horn of the medial meniscus (PHMM) during full knee flexion. A reduction in curvature may result in posteromedial tibiofemoral incongruence, a condition characterized by compression of the PHMM in full knee flexion, similar to cam incongruence in the hip joint. Clinical symptoms may occur in deep knee flexion, and progressive degeneration of the PHMM can be observed if this position is not prohibited. For patients in whom activity modification and conservative treatment have failed, surgery may be indicated. We describe arthroscopic treatment allowing for final intraoperative confirmation of the clinical indication for posteromedial tibiofemoral incongruence correction, as well as allowing for the least possible, yet sufficient, amount of correction.

The post-traumatic meniscal extrusion, sign of meniscotibial ligament injury. A case series

BACKGROUND

Medial meniscal extrusion (ME) has been found to be associated to anterior cruciate ligament (ACL) injury. Post-traumatic extrusion is mainly attributed to meniscotibial ligament (MTL) tear. The aim of this retrospective study was to assess the incidence of MTL tear associated with meniscal extrusion, evaluate arthroscopic findings and the associated clinical findings.

HYPOTHESIS

The medial meniscal extrusion, when associated to ACL injury, is related to a tear of the MTL.

PATIENTS AND METHODS

Patients who underwent to primary or revision ACL reconstruction with associated medial meniscal rise and/or meniscotibial tear or insufficiency were retrospectively identified over a 5-year period (from 2015 to 2019). Twenty-four patients were included in this study with preoperative magnetic resonance imaging (MRI) carried out at our institution Each MRI was evaluated by the senior author for the presence of meniscal extrusion and also for the additional pathology of meniscotibial ligament. Patient medical records were reviewed to obtain demographic information, including age, gender, and arthrometric evaluation of anteroposterior laxity.

RESULTS

All included patients underwent arthroscopic ACL reconstruction using autograft tissue, (19 primary and in 5 revision ACL reconstruction). The mean age was 31.2 years (range: 15-57; SD: 12.3 years) at the time of surgery. ME was identified at MRI in all cases preoperatively and confirmed arthroscopically. No correlation was found between meniscal extrusion and anteroposterior translation (ρ=-0.270; p=0.202). Neither between having more than 3mm of extrusion and gender (χ²=0.80; p=0.371), acute/chronic lesion (χ²=0.91; p=0.341) and primary/revision reconstructions (χ²=0.83; p=0.364). In the last three patients, arthroscopic treatment of meniscal extrusion was carried out through outside-in repair of medial meniscus at its capsular junction. Reduction of meniscal extrusion has been verified by MRI, performed at 3-month follow-up.

DISCUSSION

A high prevalence of ME was found at MRI in patients with ACL injury and MTL tear. Therefore, ME may be associated to acute or chronic ligamentous injury involving the MTL, and its tear can be considered as the main determinant of extrusion. Further research is needed to increase evidence concerning MTL incidence and surgical outcomes.

LEVEL OF EVIDENCE

IV, retrospective case series.

The posterior oblique ligament in MRI of acute knee trauma

OBJECTIVE

To identify the posterior oblique ligament and assess incidence and patterns of injury to the ligament on MRI of acute knee trauma.

SUBJECTS AND METHODS

One hundred twenty-three MRI studies met the study criteria. For each case, the posterior oblique ligament was identified and scored as injured or normal. Incidence of proximal and distal posterior oblique ligament tears was calculated. Fisher's tests were employed to determine significance of association between tears of the posterior oblique ligament and components of the posteromedial corner and other capsuloligamentous structures of the knee.

RESULTS

The posterior oblique ligament was reliably identified as a distinct structure in 123 MRI scans that met the criteria and was consistently labeled as intact or torn. Posterior oblique ligament tear was seen in 61.7% of knee trauma with proximal injury in 56.5% and distal injury in 97.3% of positive cases. Posterior oblique ligament disruption was a part of multiligamentous injury in 94.7% of positive cases. Posterior oblique ligament injuries (n = 76) had an extremely significant relationship with oblique popliteal ligament tears (n = 27) (p = 0.0001), semimembranosus tendon insertion tears (n = 15) (p = 0.0005), and medial collateral ligament tears (n = 15) (p = 0.0005) and a highly significant association with medial meniscus tears (n = 68) (p = 0.0049) and posterior cruciate ligament tears (n = 12) (p = 0.0033). The association with anterior cruciate ligament tears (n = 53) was not significant.

CONCLUSIONS

The posterior oblique ligament is a distinct radiological entity consistently identified in acute trauma MRI. Disruptions of the distal posterior oblique ligament are frequent in complex knee injury, notably in association with oblique popliteal ligament, medial collateral ligament, and semimembranosus tendon tears.

Meniscal Ramp Lesions: Anatomy, Epidemiology, Diagnosis, and Treatment

Injuries to the medial meniscus meniscocapsular junction, also known as ramp lesions, are common in the setting of anterior cruciate ligament injuries with a prevalence of 9% to 42%. Anatomically, ramp lesions involve disruption of the posterior meniscocapsular junction and meniscotibial ligaments. Biomechanically, ramp lesions are associated with an increase in anterior tibial translation and internal and external tibial rotation in anterior cruciate ligament-deficient cadaveric knees. Magnetic resonance imaging is useful in evaluating the meniscocapsular junction. Irregularity or increased signal near the posterior meniscocapsular junction and/or signal change indicative of posterior medial tibial plateau edema can suggest these injuries are present before surgical intervention. The current benchmark for diagnosis is arthroscopic visualization of the posterior medial meniscocapsular junction viewed through the intercondylar notch. Once a ramp lesion is identified, stability should be assessed by arthroscopic probing to determine the degree of anterior displacement. Optimal treatment has been debated in the literature, especially for stable ramp lesions, although good outcomes have been shown with and without repair. Repair is warranted for those lesions that are unstable to probing. Unfortunately, only limited literature available to guide clinicians on the optimal rehabilitation for ramp lesions.

The accuracy of MRI for the diagnosis of ramp lesions

OBJECTIVES

To assess the diagnostic accuracy of MRI in diagnosing ramp lesions in patients with an acute lesion of the anterior cruciate ligament (ACL).

MATERIALS AND METHODS

All consecutive patients over 15 years of age who underwent surgical repair of the ACL at a single hospital between January and May 2019, with MRI data available, were included in this retrospective study, except patients who had previous knee surgery. The gold standard was arthroscopic evaluation. Two trained radiologists with 5 and 14 years of experience did a blinded review of the MRIs. The following pathological signs were studied: complete fluid filling between the capsule and the posterior horn of the medial meniscus, irregular appearance of the posterior wall of the medial meniscus, oedema of the capsule, fluid hyperintensity in contact with the medial meniscus and anterior subluxation of the medial meniscus. Logistic regressions in univariate then multivariate analysis were carried out and measures of diagnostic accuracy and interobserver agreement were calculated with R software (version 3.6).

RESULTS

Fifty-seven patients were included. Twelve had a ramp lesion diagnosed by arthroscopy (21%). Only complete fluid hyperintensity between the posterior horn of the medial meniscus and the capsule was significantly associated with ramp lesions (P value < 0.01). The diagnostic accuracy of this specific sign was moderate, with a specificity of 84%, sensitivity of 75%, PPV of 56%, NPV of 93% and a good level of inter-observer agreement (k = 0.79).

CONCLUSION

The complete fluid filling is the only significant pathological MRI sign for ramp lesions, with moderate accuracy.

Incidência de lesões da rampa meniscal nas reconstruções do ligamento cruzado anterior

Objetivo Avaliar a incidência e o perfil epidemiológico das lesões da rampa meniscal nos pacientes submetidos a cirurgia de reconstrução do ligamento cruzado anterior (LCA), e determinar os fatores de risco relacionados.

Métodos Foram analisados retrospectivamente 824 pacientes submetidos a cirurgia de reconstrução do LCA. Os pacientes que apresentaram instabilidade meniscal medial foram submetidos a avaliação do compartimento posteromedial do joelho. Em caso de lesão, o reparo cirúrgico foi realizado. Potenciais fatores de risco associados às lesões foram analisados.

Resultados A incidência geral de lesões da rampa na população estudada foi de 10,6% (87 lesões em 824 pacientes). A análise multivariada pelo teste do Qui-quadrado demonstrou que a presença de lesões da rampa meniscal foi significativamente associada aos seguintes fatores de risco: lateralidade direita e lesões crônicas. Sexo, idade e atividade esportiva não foram estatisticamente significantes. O futebol foi a causa mais frequente de lesões da rampa relacionadas ao esporte, com 78,2% dos casos. No entanto, não se mostrou ser um fator de risco. De 2014 a 2019, a incidência anual variou de 4,0% a 20,6%.

Conclusão A incidência das lesões da rampa meniscal foi de 10,6% nas cirurgias de reconstrução do LCA, sendo mais frequente em pacientes com lesões crônicas. A incidência anual foi crescente, e variou de 4,0%, em 2014, a 20,6%, em 2019.

Isolated Meniscotibial Ligament Rupture: The Medial Meniscus "Belt Lesion"

Ramp lesions play a major role in both anteroposterior and rotational instability following anterior cruciate ligament rupture. The meniscotibial ligament (MTL) is the most important structure to repair and is the primary stabilizer of the posterior horn of the medial meniscus. The posteroinferior insertion of the MTL on the posterior horn of the medial has been described, forming a posterior "belt." Isolated MTL lesion diagnosis can be challenging, as the absence of a meniscocapsular ligament lesion prevents its correct visualization through transnotch vision. This article details a technique to diagnose and repair the "belt lesion" of the medial meniscus.

Ramp lesions are six times more likely to be observed in the presence of a posterior medial tibial bone bruise in ACL-injured patients

PURPOSE

The aim of this study was to determine whether posterior tibial slope (PTS), meniscal slope (MS), and bone bruise pattern (BBP), as observed on magnetic resonance imaging (MRI), differed between patients with or without medial meniscus ramp lesions at the time of anterior cruciate ligament reconstruction (ACLR). The hypothesis was that patients with a ramp lesion had a higher PTS and MS, with a different BBP than patients without a ramp lesion.

METHODS

Fifty-six patients undergoing ACLR were selected from an in-house registry and separated into 2 groups: (1) the RAMP group included patients with a primary ACLR and a medial meniscus ramp lesion diagnosed intraoperatively; (2) the CONTROL group included patients with a primary ACLR without ramp lesion after arthroscopic exploration of the posteromedial knee area. The two groups were matched for age, sex and type of concomitant meniscal lesions. The medial/lateral-PTS/MS and BBP were subjected to blinded evaluation on the preoperative MRI of the reconstructed knee.

RESULTS

Twenty eight patients (21 males; 7 females) were included in each group. No significant difference could be observed between groups in terms of demographical characteristics, PTS, and MS. A posteromedial tibial plateau (PMTP) bone bruise was more often observed in the RAMP group (n = 23/28) compared to the CONTROL group (n = 12/28) (p < 0.01). The RAMP group was 6.1 (95%CI [1.8; 20.8]) times more likely to present a PMTP bone bruise. The likelihood of having a bone bruise in both the medial and lateral compartments was 4.5 (95%CI [1.2; 16.5]) times higher in the RAMP group. However, a BBP only involving the lateral tibiofemoral compartment was more likely to be observed in the CONTROL group (n = 10/28) compared to the RAMP group (n = 3/28, p < 0.05 - odds ratio 4.6 (95%CI [1.1; 19.2]).

CONCLUSION

Ramp lesions were 6.1 and 4.5 times more likely to be observed in the presence of a posteromedial tibia plateau bone bruise or a combined bone bruise respectively in both the medial and lateral tibiofemoral compartment in patients undergoing ACLR. The tibial and meniscal slopes did not differ between patients with or without ramp lesions undergoing ACLR.

LEVEL OF EVIDENCE

Level III.

Semimembranosus Tendon Advancement for the Anteromedial Knee Rotatory Instability Treatment

Injury to the medial compartment of the knee is the most common ligament injury to this joint. The medial approach must consider the presence of associated anteromedial instability. Untreated injury of these instabilities can result in failure of the other reconstructed ligaments. As treatment is usually associated with other ligaments, it is relevant that the technique could save grafts and synthetic material. This article aims to describe a technique for the treatment of anteromedial instabilities through semimembranosus tendon tenodesis in a more anterior and distal position, promoting the tensioning of the posteromedial structures.

An Increased Lateral Femoral Condyle Ratio Is an Important Risk Factor for a Medial Meniscus Ramp Lesion Including Red-Red Zone Tear

PURPOSE

This study aimed to determine radiological findings associated with ramp lesions in knees with anterior cruciate ligament (ACL) injury.

METHODS

This study included the primary ACL reconstructions from June 2011 to March 2019. The exclusion criteria were combined fractures and multiligament injuries. Patients were categorized based on arthroscopy-confirmed presence of ramp lesions, which was defined as a longitudinal tear around the meniscocapsular junction or red-red zone tear of medial meniscus posterior horn. Binary logistic regression analysis was performed to find the risk factors such as age, sex, body mass index, medial tibial slope, mechanical axis angle, presence of Segond fracture, and lateral femoral condyle (LFC) ratio. Additionally, receiver operating characteristic (ROC) curves and area under the ROC curve (AUC) were evaluated.

RESULTS

Ramp lesions were identified in 89 (27.7%) patients among the total 321 included primary ACL reconstructions. The risk of ramp lesion was associated with increased LFC ratio (odds ratio [OR]: 62.929; 95% confidence interval [CI]: 8.473-467.351; P < .001), varus alignment >3° (OR: 5.858; 95% CI: 3.272-10.486; P < .001), and steeper medial tibial slope (OR: 1.183; 95% CI: 1.05-1.333; P = .006). The cutoff values of the LFC ratio and medial tibial slope for ramp lesions were >71% (AUC: 0.696; sensitivity: 43.82%; specificity: 91.38%; P < .001) and >12.1° (AUC: 0.643; sensitivity: 85.39%; specificity: 38.79%; P < .001), respectively.

CONCLUSION

Deep posterior LFC, varus alignment, and steep medial tibial slope were associated factors for ramp lesions in knees with ACL injury. In patients with ACL injury who show the above-mentioned radiographic findings, careful assessment and suspicion for ramp lesions should be considered.

STUDY DESIGN

Level III, retrospective cross-sectional study.

Bony injury associated with ramp lesion and a double meniscal injury - A hidden terrible triad of the posteromedial knee

Ramp lesions are important injuries that are difficult to detect on MRI and pose a challenge to diagnose on arthroscopy since they require inspection of the posteromedial compartment. No bony injury has been reported in the literature as an associated injury with the ramp lesion. We report a rare case of complete ramp tear of the posterior capsule-meniscal junction associated with fracture of the rim of the posterior medial tibial plateau and a double injury to the posterior medial meniscus forming a terrible triad with poor prognosis. This report has implications on the classifications of ramp lesions, posterior root injuries of the medial meniscus and meniscal tears as fracture of the rim adds a new dimension to these injuries.

Diagnostic Accuracy of Magnetic Resonance Imaging in the Detection of Type and Location of Meniscus Tears: Comparison with Arthroscopic Findings

Magnetic resonance imaging (MRI) has been widely used for the diagnosis of meniscal tears, but its diagnostic accuracy, depending on the type and location, has not been well investigated. We aimed to evaluate the diagnostic accuracy of MRI by comparing MRI and arthroscopic findings. Preoperative 3.0-T MRI and arthroscopic findings from 2005 to 2018 were reviewed to determine the presence, type, and location of meniscus tears. In addition, subgroup analysis was performed according to anterior cruciate ligament (ACL) injury. The exclusion criteria were as follows: (1) Inflammatory arthritis, (2) other ligament injuries, (3) inability to classify meniscal tears due to degenerative arthritis, (4) over 90 days from MRI to surgery, and (5) incomplete data. Of the 2998 eligible patients, 544 were finally included. The sensitivity and specificity of MRI in determining medial and lateral meniscus tears were 91.8% and 79.9%, and 80.8% and 85.4%, respectively. The accuracy of MRI in the ACL-injured group was lower than that in the ACL-intact group (medial meniscus: 81.7% vs. 88.1%, p = 0.041; 72.9% vs. lateral meniscus: 88.0%, p < 0.001). MRI accuracy was low for the longitudinal tears of the posterior horn of the medial meniscus in the ACL-injured group. MRI could be a diagnostic tool for meniscus tears, but has limited accuracy in their classification of the type and location. Hence, care should be taken during arthroscopic assessment of ACL-injured patients due to low diagnostic accuracy of preoperative MRI.

What Is the Relationship Between the Distal Semimembranosus Tendon and the Medial Meniscus? A Gross and Microscopic Analysis From the SANTI Study Group

BACKGROUND

Some authors have suggested that the semimembranosus tendon is involved in the pathophysiology of ramp lesions. This led us to conduct a gross and microscopic analysis of the posterior horn of the medial meniscus and the structures inserted on it.

HYPOTHESIS

(1) The semimembranosus tendon has a tendinous branch inserting into the posterior horn of the medial meniscus, and (2) the meniscotibial ligament is inserted on the posteroinferior edge of the medial meniscus.

STUDY DESIGN

Descriptive laboratory study.

METHODS

In total, 14 fresh cadaveric knees were dissected. From each cadaveric donor, a stable anatomic specimen was harvested en bloc, including the medial femoral condyle, medial tibial plateau, whole medial meniscus, cruciate ligaments, joint capsule, and distal insertion of the semimembranosus tendon. The harvested blocks were cut along the sagittal plane to isolate the distal insertion of the semimembranosus tendon on the posterior joint capsule and the posterior horn of the medial meniscus in a single slice. Histological slides were made from these samples and analyzed under a microscope.

RESULTS

In all knees, gross examination revealed a direct branch of the semimembranosus and a tendinous capsular branch ending behind the posterior horn of the medial meniscus. This capsular branch protruded over the joint capsule, over the meniscotibial ligament below and the meniscocapsular ligament above, but never ended directly in the meniscal tissue. The capsular branch was 14.3 ± 4.4 mm long (mean ± SD). The direct tendon inserted 11 ± 2.8 mm below the articular surface of the tibial plateau. The meniscotibial ligament inserted on the posteroinferior edge of the medial meniscus, and the meniscocapsular ligament insertion was on its posterosuperior edge. Highly vascularized adipose tissue was found, delimited by the posterior horn of the medial meniscus, meniscotibial ligament, meniscocapsular ligament, and capsular branch of the semimembranosus tendon.

CONCLUSION

In all knees, our study found a capsular branch of the semimembranosus tendon inserted behind the medial meniscus. The meniscotibial ligament was inserted on the posteroinferior edge of the medial meniscus. Histological analysis of this area revealed that this ligament inserted differently from the insertion previously described in the literature.

CLINICAL RELEVANCE

This laboratory study provides insight into the pathophysiology of ramp lesions frequently associated with anterior cruciate ligament injury. To restore anatomy, it is mandatory to reestablish meniscotibial ligament continuity in ramp repairs.

Posterior Oblique Ligament Repair Concomitant to Anterior Cruciate Ligament Reconstruction

The associated lesion of the posterior oblique ligament (POL) in the setting of anterior cruciate ligament rupture is quite frequent due to the same rotational mechanism. The diagnosis of POL lesions is challenging, and physical examination is delicate; moreover, they can be easily missed on magnetic resonance imaging. Once recognized, POL lesions must be repaired to restore posteromedial corner kinematics. The aim of this Technical Note is to present a safe and effective method for POL repair in the set of an anterior cruciate ligament reconstruction.

Diagnostic performance of open MRI in the flexed knee position for the detection of medial meniscus ramp lesions

OBJECTIVES

To identify the diagnostic performance of magnetic resonance imaging (MRI) in the knee-flexed position for the detection of meniscal ramp lesions in patients with anterior cruciate ligament tears.

MATERIALS AND METHODS

Forty-three patients (mean age 24.5 ± 9.5 years; 21 males, 22 females) with an arthroscopically proven anterior cruciate ligament tear were included in this retrospective study. The presence of the following two important features on MRI was recorded: irregularity of the medial meniscus at the posterior margin, and complete fluid filling between the posterior horn of the medial meniscus and the capsule margin. Findings obtained in arthroscopy served as the reference standard. The diagnostic sensitivity, specificity, and inter-observer agreement were calculated.

RESULTS

Sixteen ramp lesions were noted on arthroscopy (37.2%). With an irregularity of the medial meniscus at the posterior margin on MRI, the sensitivity and specificity were 87.5 and 59.3% at 10° knee flexion and 93.8 and 85.2% at 90° flexion, respectively. The complete fluid filling sign on MRI showed sensitivity and specificity of 31.3 and 100% at 10° knee flexion and 87.5 and 100% at 90° flexion, respectively. The concordance between the two observers for the two MRI features was very good (k = 0.70-0.88).

CONCLUSION

MRI with the knee in the flexed position improves the diagnostic performance of the detection of meniscal ramp lesions compared with MRI with the knee in the extended position.

Editorial Commentary: Ramp Lesion: The Eye Sees Only What the Mind Is Prepared to Comprehend

If our consciousness is not prepared, it is difficult to identify a ramp lesion on preoperative magnetic resonance imaging due to its low sensitivity. In clinical practice, the prevalence of ramp lesion in the anterior cruciate ligament (ACL)-injured knee can be up to 30%, with an increased frequency in chronic ACL injuries and in revision ACL. To identify the ramp lesion, routine arthroscopic exploration of the posteromedial portion of knee using a trans-notch view during ACL reconstruction therefore seems essential. A decrease in reoperation rate for secondary meniscectomy from 25% to 7% since 2013 was published by our department, after the adoption of a systematic repair through a posteromedial portal with a suture hook device for ramp lesions identified at the time of ACL reconstruction.

Ramp lesions: a systematic review of MRI diagnostic accuracy and treatment efficacy

Purpose

We conducted a systematic review of the published literature to assess the accuracy of Magnetic Resonance Imaging (MRI) in establishing the presence of ramp lesions (RLs) in Anterior Cruciate Ligament (ACL) deficient knees and the clinical efficacy of the surgical repair of RLs.

Methods

A comprehensive search of the MEDLINE, Web of Science and Scopus databases was performed according to PRISMA guidelines. Studies assessing MRI diagnostic accuracy for RLs or the clinical effect of RL repair in participants with ACL injuries were included. Diagnostic accuracy measures were pooled and plotted in forest plots. Preoperative and at last follow-up treatment efficacy outcome measures were extracted and plotted in forest plots, for graphical comprehension.

Results

Sixteen studies met the criteria and were included. The diagnostic analysis showed a pooled sensitivity, specificity, positive and negative likelihood ratios of 65.1% (95% CI, 59.73 to 70.42), 91.6% (95% CI, 89.14 to 94.05), 2.91 (95% CI, 2.38–3.55) and 0.53 (95% CI, 0.44–0.64), respectively, with high heterogeneity (I² above 80%) for all measures. Treatment analysis showed improved Lysholm Knee Score, IKDC score and laxity difference between the knees in all studies after meniscal suture repair. A separate analysis showed no differences between repair of smaller, stable, RLs with meniscal sutures and repair with abrasion and trephination only.

Conclusion

Although the results present considerable heterogeneity, MRI seems to demonstrate moderate accuracy in the diagnosis of RLs in patients with ACL tear and the surgical repair of RLs can be associated with improved overall outcomes.