Posterior horn instability of the medial meniscus a sign of posterior meniscotibial ligament insufficiency

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.

The meniscotibial ligament does exist: An anatomic and histological description

Purpose

To describe the anatomical and histological characteristics of the human MTL (meniscotibial ligament) that keeps the meniscus stable and are rarely discussed.

Study design

Descriptive laboratory study.

Methods

In total, six fresh-frozen adult cadaver knees were dissected, and the dissection protocol were designed by two experienced anatomy professors. The anatomical morphology of MTL was observed. The main anatomical specimens included meniscus, tibial plateau, MTL. The osteotome was used to excise the portion of the tibial plateau, which could obtain the complex including partial meniscus, MTL, and a tibial fragment. A histopathologic study was performed by two experienced pathologists.

Results

Macroscopically, the MTL could be divided into two parts: medial meniscotibial ligament (MMTL)and lateral meniscotibial ligament (LMTL). The MMTL is distributed continuously, whereas the LMTL is discontinuous on the tibial plateau. The average length from the tibial attachment of the LMTL to the articular surface was 19 ± 1.0mm (mean ± SD). The average length from the tibial attachment of the MMTL to the articular surface was 10 ± 1.2 mm (mean ± SD). Microscopy of the MTL showed that the MTL is a ligamentous tissue, composed of a network of oriented collagenous fibers.

Conclusions

In all knees, the MTL was inserted on the outer edge of the meniscus, attaching to the tibia below the level of articular cartilage, which was key to maintaining the rotational stability of knee and the meniscus in the physiological position on the tibial plateau. Histological analysis of this ligament demonstrated that the MTL is a veritable ligamentous structure, which is made up of collagen type I-expressing fibroblasts.

Clinical relevance

This article contributes to the understanding of the anatomical and histological characteristics of the MTL. It is beneficial to promote the development of relevant surgical techniques for the MTL lesion.

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.

Arthroscopic All-Suture Anchor Technique for Unstable Ramp Lesions with Medial Meniscal Defects

A ramp lesion is a specific type of tear in the meniscocapsular junction of the posterior horn of the medial meniscus, usually associated with anterior cruciate ligament (ACL) injury. Biomechanical cadaveric studies have shown that ACL injury combined with ramp lesions significantly increases anterior tibial translation and external rotation, which ACL reconstruction alone cannot completely control. Additionally, ramp lesions are sometimes associated with medial meniscal defects, especially in cases of chronic ACL deficiency after repetitive traumatic events, in which the anatomical repair of the meniscocapsular junction is infeasible. This report describes a new arthroscopic repair technique using an all-suture anchor through a posteromedial portal for unstable ramp lesions with medial meniscal defects.

Quantifying Meniscal Extrusion Using Ultrasound in the Setting of Concomitant Cadaveric Knee Lesions: Part I: The Medial Meniscotibial Ligament and Posterior Medial Meniscal Root

PURPOSE

1. Evaluate how the meniscotibial ligament (MTL) affects meniscal extrusion (ME) +/- concomitant posterior medial meniscal root (PMMR) tears. 2. Describe how ME varied along length of meniscus.

METHODS

ME was measured using ultrasonography in 10 human cadaveric knees in conditions: (1) control, either (2a) isolated MTL sectioning, or (2b) isolated PMMR tear, (3) combined PMMR + MTL sectioning, and (4) PMMR repair. Measurements were obtained 1 cm anterior to the MCL (anterior), over the MCL (middle), and 1 cm posterior to the MCL (posterior) +/- 1000N axial loads in 0° and 30° flexion.

RESULTS

At 0°, MTL sectioning demonstrated greater middle than anterior (P<0.001) and posterior (P<0.001) ME, while PMMR (P=0.0042) and PMMR+MTL (P<0.001) sectioning demonstrated greater posterior than anterior ME. At 30°, PMMR (P<0.001) and PMMR+MTL (P<0.001) sectioning demonstrated greater posterior than anterior ME, and PMMR (P=0.0012) and PMMR+MTL (P=0.0058) sectioning demonstrated greater posterior than anterior ME. PMMR+MTL sectioning demonstrated greater posterior ME at 30° compared to 0° (P=0.0320). MTL sectioning always resulted in greater middle ME (P<0.001), in contrast with no middle ME changes following PMMR sectioning. At 0°, PMMR sectioning resulted in greater posterior ME (P<0.001), but at 30°, both PMMR and MTL sectioning resulted in greater posterior ME (P<0.001). Total ME surpassed 3 mm only when both the MTL and PMMR were sectioned.

CONCLUSION

The MTL and PMMR contribute most to ME when measured posterior to the MCL at 30° of flexion. ME greater than 3 mm is suggestive of combined PMMR + MTL lesions.

CLINICAL RELEVANCE

Overlooked MTL pathology may contribute to persistent ME following PMMR repair. We found isolated MTL tears able to cause 2-2.99 mm of ME, but the clinical significance of these magnitudes of extrusion is unclear. The use of ME measurement guidelines with ultrasound may allow for practical MTL and PMMR pathology screening and pre-operative planning.

Pivot shift intraoperative quantitative assessment using a smartphone accelerometer in ACL deficient knees

PURPOSE

The Pivot Shift (PS) test is a complex clinical sign that assesses the internal rotation and anterior tibial translation, which occurs abnormally in ACL deficient-knees. Because of the high inter-observer variability, different devices have been designed to characterize this complex movement in quantitative variables. The objective of this pilot study is to validate the reproducibility of intraoperative quantitative assessment of the PS with a smartphone accelerometer.

METHODS

Twelve ACL-injured knees were included and compared with the contralateral uninjured side. The PS was measured by two independent observers utilizing a smartphone accelerometer and graded according to the IKDC classification. Measurements were taken preoperatively, intraoperatively and postoperatively. Intraoperative readings were taken during each stage of reconstruction or repair of meniscoligamentous lesions including meniscal lesions, ramp lesions, ACL reconstruction and lateral tenodesis. Reproducibility of the measurements were evaluated according to an intraclass correlation coefficient (ICC).

RESULTS

The intra-observer reliability was good for the first examiner and excellent for the second examiner, with the ICC 0.89 [0.67, 0.98] p < 0,001 and ICC 0.97 [0.91, 1.0] p < 0,001 respectively. The inter-observer reliability was excellent between the two observers with the ICC 0.99 [0.97, 1.0] p < 0,001. The mean tibial acceleration measured 3.45 m.s² (SD = 1.71) preoperatively on the injured knees and 1.03 m.s² (SD = 0.36) on the healthy knees, demonstrating a significant difference following univariate analysis p < 0.001. Postoperatively, no significant difference was observed between healthy and reconstructed knees The magnitudes of tibial acceleration values were correlated with the PS IKDC grade.

CONCLUSION

The smartphone accelerometer is a reproducible device to quantitatively assess the internal rotation and anterior tibial translation during ACL reconstruction surgery. The measurements are influenced by the different surgical steps. Other larger cohort studies are needed to evaluate the specific impact of each step of the ACL reconstruction and meniscal repair on this measurement. An external validation using other technologies are needed to validate the reliability of this device to assess the PS test.

LEVEL OF EVIDENCE

Level IV, case series, pilot study.

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.

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.

Examining Techniques for Treatment of Medial Meniscal Ramp Lesions During Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

The purpose of this study was to systematically review the clinical outcomes and adverse events among different techniques for treatment of medial meniscal ramp lesions performed in conjunction with anterior cruciate ligament (ACL) reconstruction.

METHODS

A systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Cochrane Reviews, Web of Science, and Medline databases were searched for studies examining clinical outcomes after surgical treatment of ramp lesions. Studies were selected if they met the following criteria: (1) evaluation of the outcome of surgical repair of meniscal ramp lesions, (2) injuries associated with ACL tears, (3) minimum 6-month follow up, (4) publication in a peer-reviewed journal, and (5) English language or translation readily available.

RESULTS

Seven studies met inclusion criteria (485 patients; mean age 27.1 years [range 12 to 59]; mean follow-up 26.9 months [range 8 to 40]). Two all-inside techniques (suture-hook and an all-inside meniscus repair device) in addition to abrasion and trephination alone were analyzed. Each technique demonstrated significant increases in postoperative Lysholm and International Knee Documentation Committee (IKDC) scores, reaching the established minimal clinically important difference (MCID) for each patient reported outcome. Incomplete healing was documented in 12.1% to 12.9% of cases in which the tear was not repaired at the time of ACL reconstruction, 2.3% to 11.7% in cases using the suture-hook for repair, and 10.8% to 15% in the all-inside meniscus repair device group.

CONCLUSION

This systematic review demonstrated that several approaches used to treat medial meniscal ramp lesions associated with ACL tears lead to positive clinical outcomes. Small, stable tears <2 cm in size may be managed with debridement alone. For larger, more unstable lesions, an all-inside approach has demonstrated positive clinical outcomes. Prospective trials are needed to determine the best management for meniscal ramp lesions. Additionally, further research is needed to better understand how to minimize the risk of technique-related complications (e.g., improper implant deployment).

LEVEL OF EVIDENCE

Level IV, systematic review of level II, III, and IV studies.

Meniscal ramp lesions should be considered in anterior cruciate ligament-injured knees, especially with larger instability or longer delay before surgery

PURPOSE

To determine the incidence of meniscal ramp lesions in an anterior cruciate ligament (ACL) injured knees and to clarify whether ramp lesions are related to chronic ACL deficiency and increased knee instability.

METHODS

Consecutive ACL injured patients were evaluated arthroscopically for a ramp lesion via a trans-notch view and evidence of menisco-capsular injury was recorded. Other concomitant injuries to the knee were also noted. Incidence of meniscal ramp lesions, delay before surgery, and anterior-posterior stability was analyzed. All patients underwent bilateral KT-2000 evaluation.

RESULTS

One hundred and three consecutive ACL injured patients with a mean age of 24 years were included in this study. In total, a ramp lesion was found in 10 knees (9.7%) via a trans-notch view. None of these lesions could be identified by the standard view from the anterolateral portal. Other medial meniscal lesions were found in 26 knees (25.2%) by standard arthroscopic viewing. The ramp lesion group had significantly longer delay before surgery with a median of 191 days (p < 0.01) as well as a larger side-to-side difference of KT-2000 measurement (7.3 ± 1.8 mm; p < 0.01), compared with the intact medial meniscus group (53 days and 5.5 ± 1.5 mm, respectively).

CONCLUSION

Ramp lesions that were identified using a trans-notch view were not visualized with standard arthroscopic views. Increased anterior tibial translation and longer delay before surgery were seen in knees with ramp lesions. Careful inspection of the posteromedial menisco-capsular region is required as hidden menisco-capsular lesions may occur which may result in residual knee instability.

LEVEL OF EVIDENCE

Level II.

Ramp Lesions: An Unrecognized Posteromedial Instability?

Meniscal ramp lesions occur much more frequently than was previously considered, and particularly so in ACL-injured knees. The historically high rate of missed diagnoses is a result of unfamiliarity with this injury pattern within the orthopedic community, and also the difficulty in diagnosis. A systematic exploration of the posteromedial compartment of the knee is mandatory to reliably identify ramp lesions. Failure to recognize and repair these injuries is associated with persistent anterior and posteromedial instability. Understanding their nature, biomechanics, and epidemiology is essential in allowing orthopedic surgeons to suspect their presence and adequately treat these lesions.

Effect of Meniscal Ramp Lesion Repair on Knee Kinematics, Bony Contact Forces, and In Situ Forces in the Anterior Cruciate Ligament

BACKGROUND

Meniscal ramp lesions are possible concomitant injuries in cases of anterior cruciate ligament (ACL) deficiency. Although recent studies have investigated the influence of ramp lesions on knee kinematics, the effect on the ACL reconstruction graft remains unknown.

PURPOSE/HYPOTHESIS

The purpose was to determine the effects of ramp lesion and ramp lesion repair on knee kinematics, the in situ forces in the ACL, and bony contact forces. It was hypothesized that ramp lesions will significantly increase in situ forces in the native ACL and bony contact forces and that ramp lesion repair will restore these conditions comparably with those forces of the intact knee.

STUDY DESIGN

Controlled laboratory study.

METHODS

Investigators tested 9 human cadaveric knee specimens using a 6 degrees of freedom robotic testing system. The knee was continuously flexed from full extension to 90° while the following loads were applied: (1) 90-N anterior load, (2) 5 N·m of external-rotation torque, (3) 134-N anterior load + 200-N compression load, (4) 4 N·m of external-rotation torque + 200-N compression load, and (5) 4 N·m of internal-rotation torque + 200-N compression load. Loading conditions were applied to the intact knee, a knee with an arthroscopically induced 25-mm ramp lesion, and a knee with an all-inside repaired ramp lesion. In situ forces in the ACL, bony contact forces in the medial compartment, and bony contact forces in the lateral compartment were quantified.

RESULTS

In response to all loading conditions, no differences were found with respect to kinematics, in situ forces in the ACL, and bony contact forces between intact knees and knees with a ramp lesion. However, compared with intact knees, knees with a ramp lesion repair had significantly reduced anterior translation at flexion angles from full extension to 40° in response to a 90-N anterior load (P < .05). In addition, a significant decrease in the in situ forces in the ACL after ramp repair was detected only for higher flexion angles when 4 N·m of external-rotation torque combined with a 200-N compression load (P < .05) and 4 N·m of internal-rotation torque combined with a 200-N compression load were applied (P < .05).

CONCLUSION

In this biomechanical study, ramp lesions did not significantly affect knee biomechanics at the time of surgery.

CLINICAL RELEVANCE

From a biomechanical time-zero perspective, the indications for ramp lesion repair may be limited.

Incidence of Posteromedial Meniscocapsular Separation and the Biomechanical Implications on the Anterior Cruciate Ligament

PURPOSE

To report the incidence of posterior medial meniscocapsular junction (PMCJ) separation in patients with anterior cruciate ligament (ACL) injury and to evaluate its biomechanical effect on the ACL.

METHODS

Three hundred thirty-seven consecutive patients undergoing isolated primary ACL reconstruction were retrospectively analyzed for PMCJ lesion. Forty-four patients were identified with PMCJ lesion and studied. Eight cadaver knees underwent biomechanical testing to determine anterior tibial displacement and anteromedial bundle ACL strain in the intact, PMCJ lesion, and PMCJ repair states at 0°, 30°, 60°, and 90° of flexion. Mixed-effects linear regression with Bonferroni correction was used for statistical analysis.

RESULTS

PMCJ tear incidence with ACL disruption was 13.1%. Specimen with PMCJ tears had statistically increased anterior tibial translation at 30° (1.2 mm; P < 0.01) and statistically increased ACL strain at 30° (24%; P < 0.01) and 90° (50%; P < 0.01). With PMCJ repair, translation reduced (P > 0.05) by 12%, 18%, and 10% at 0°, 30°, and 90° of flexion, respectively. PMCJ repair reduced (P < 0.05) ACL strain by 40%, 39%, 43%, and 31% at 0°, 30°, 60°, and 90° of flexion, respectively.

CONCLUSIONS

A PMCJ lesion was observed in 13% of ACL injuries. This injury contributes to increased ACL strain, and PMCJ repair markedly reduces ACL strain to preinjury levels.

Epidemiological Evaluation of Meniscal Ramp Lesions in 3214 Anterior Cruciate Ligament-Injured Knees From the SANTI Study Group Database: A Risk Factor Analysis and Study of Secondary Meniscectomy Rates Following 769 Ramp Repairs

BACKGROUND

Ramp lesions are characterized by disruption of the peripheral meniscocapsular attachments of the posterior horn of the medial meniscus. Ramp repair performed at the time of anterior cruciate ligament reconstruction (ACLR) has been shown to improve knee biomechanics.

PURPOSE

The primary objectives of this study were to evaluate the incidence of and risk factors for ramp lesions among a large series of patients undergoing ACLR. Secondary objectives were to determine the reoperation rate for failure of ramp repair, defined by subsequent reoperations for partial medial meniscectomy.

STUDY DESIGN

Case-control study; Level of evidence, 3. Case series; Level of evidence, 4.

METHODS

All patients underwent transnotch posteromedial compartment evaluation of the knee during ACLR. Ramp repair was performed if a lesion was detected. Potentially important risk factors were analyzed for their association with ramp lesions. A secondary analysis of all patients who underwent ramp repair and had a minimum follow-up of 2 years was undertaken to determine the secondary partial meniscectomy rate for failed ramp repair.

RESULTS

The overall incidence of ramp lesions in the study population was 23.9% (769 ramp lesions among 3214 patients). Multivariate analysis demonstrated that the presence of ramp lesions was significantly associated with the following risk factors: male sex, patients aged <30 years, revision ACLR, chronic injuries, preoperative side-to-side laxity >6 mm, and concomitant lateral meniscal tears. The secondary meniscectomy rate was 10.8% at a mean follow-up of 45.6 months (range, 24.2-66.2 months). Patients who underwent ACLR + anterolateral ligament reconstruction had a >2-fold reduction in the risk of reoperation for failure of ramp repair as compared with patients who underwent isolated ACLR (hazard ratio, 0.457; 95% CI, 0.226-0.864; P = .021).

CONCLUSION

There is a high incidence of ramp lesions among patients undergoing ACLR. The identification of important risk factors for ramp lesions should help raise an appropriate index of suspicion and prompt posteromedial compartment evaluation. The overall secondary partial meniscectomy rate after ramp repair is 10.8%. Anterolateral ligament reconstruction appears to confer a protective effect on the ramp repair performed at the time of ACLR and results in a significant reduction in secondary meniscectomy rates.

Is Edema at the Posterior Medial Tibial Plateau Indicative of a Ramp Lesion? An Examination of 307 Patients With Anterior Cruciate Ligament Reconstruction and Medial Meniscal Tears

Background:

Medial meniscal tears are commonly seen during anterior cruciate ligament reconstruction (ACLR). A subset of these injuries includes posterior meniscocapsular junction or “ramp” tears. One criterion that may correlate with a ramp lesion is the presence of posterior medial tibial plateau (PMTP) edema.

Purpose:

To compare patients with ramp lesions to patients with nonramp (meniscal body) medial meniscal tears and correlate PMTP edema on preoperative magnetic resonance imaging (MRI) to the incidence of ramp tears.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

From 2006 to 2016, a total of 852 patients underwent ACLR and had operative reports available for review. Age, sex, laterality, mechanism of injury (contact/noncontact), sport, revision procedure, multiligament injury, time to MRI, and time to surgery were recorded. Preoperative MRI scans were reviewed for PMTP edema using axial, coronal, and sagittal T2 and proton-density sequences. Differences between groups were analyzed using a 2-sample t test and chi-square test. Univariate and multivariate logistic regression models examined correlations with tear type.

Results:

Overall, 307 patients had medial meniscal tears identified during ACLR (127 ramp lesions, 180 meniscal body lesions). The ramp group was 7.5 years younger than the meniscal body group (P < .01). The groups were not different regarding sex, contact injury, revision surgery, laterality, or multiligament injury. Patients with delayed ACLR were significantly more likely to have a meniscal body tear than a ramp lesion (odds ratio, 3.3 [95% CI, 1.9-5.6]; P < .01). The sensitivity of PMTP edema for a ramp tear was 66.3%, and 54.5% of patients with ACLR and a medial meniscal tear had PMTP edema. Patients with PMTP edema were significantly more likely to have a ramp tear than a meniscal body tear (odds ratio, 2.1 [95% CI, 1.1-4.1]; P < .03).

Conclusion:

The overall incidence of ramp tears in patients undergoing ACLR was 14.9%, and these tears were more prevalent in younger patients. Meniscal body tears were significantly more likely than ramp tears with delayed ACLR. In patients undergoing ACLR with an associated medial meniscal tear, the presence of PMTP edema demonstrated significantly greater odds for ramp lesions compared with meniscal body tears.

Diagnostic Accuracy of Sequential Arthroscopic Approach for Ramp Lesions of the Posterior Horn of the Medial Meniscus in Anterior Cruciate Ligament-Deficient Knee

PURPOSE

To document the diagnostic accuracy and steps for sequential arthroscopic exploration of ramp lesions-peripheral tear within 4 mm of meniscocapsular junction of medial meniscus-associated with anterior cruciate ligament (ACL) injury.

METHODS

This was a prospective consecutive study of 195 primary ACL reconstructions with arthroscopic exploration for ramp lesion in 4 steps: (1) standard exploration through the anterolateral portal, (2) through the intercondylar space using a 30° arthroscope, (3) through the intercondylar space using a 70° arthroscope, and (4) after creation of a posteromedial portal. Acute (<3 months) and chronic case (>3 months) groups were compared, and the sensitivity and specificity of magnetic resonance imaging (MRI) were assessed.

RESULTS

Overall, 50 patients (26.6%) were confirmed as having a ramp lesion. After step 1, only 19 cases (38%) were identified as a ramp lesion. After step 2, 24 cases (48%) were found, and the sensitivity of step 2 was estimated at 48%. After step 3, an additional 26 cases (52%) were identified. No more additional cases of ramp lesion were found after step 4. There were statistically significant differences between steps 2 and 3 (P = .001), but no differences between steps 1 and 2, or steps 3 and 4. Although there were no statistical differences in overall prevalence for acute (28/128, 21.8%) and chronic (22/67, 32.8%) groups (P = .136), the incidence of ramp lesion confirmed through the standard portal approach was found to be significantly correlated with chronic group (odds ratio: 2.95, P = .023). The sensitivity and specificity of preoperative MRI were 84% and 95.17%.

CONCLUSIONS

Many ramp lesions could not be diagnosed through the standard portal and intercondylar space using a 30° arthroscope. Posteromedial inspection using a 70° arthroscope has improved the diagnostic accuracy for ramp lesion without direct exploration through the posteromedial portal. Care should be taken to identify ramp lesions when ACL reconstruction is performed.

LEVEL OF EVIDENCE

Level I, diagnostic study of consecutive patients.

Underappreciated Factors to Consider in Revision Anterior Cruciate Ligament Reconstruction: A Current Concepts Review

Primary anterior cruciate ligament (ACL) reconstructions (ACLRs) are being performed with increasing frequency. While many of these will have successful outcomes, failures will occur in a subset of patients who will require revision ACLRs. As such, the number of revision procedures will continue to rise as well. While many reviews have focused on factors that commonly contribute to failure of primary ACLR, including graft choice, patient factors, early return to sport, and technical errors, this review focused on several factors that have received less attention in the literature. These include posterior tibial slope, varus malalignment, injury to the anterolateral ligament, and meniscal injury or deficiency. This review also appraised several emerging techniques that may be useful in the context of revision ACL surgery. While outcomes of revision ACLR are generally inferior to those of primary procedures, identifying these potentially underappreciated contributing factors preoperatively will allow the surgeon to address them at the time of revision, ideally improving patient outcomes and preventing recurrent ACL failure.

Correlation between time from injury to surgery and the prevalence of ramp and hidden lesions during anterior cruciate ligament reconstruction. A new diagnostic algorithm

Background

Anterior cruciate ligament tears (ACL) are associated with meniscal lesions, that could involve the posterior horn of the medial meniscus (PHMM). A variety of techniques has been proposed to better visualise the postero-medial (PM) compartment. The aim of the study is to evaluate the prevalence of longitudinal tears of peripheral attachment of the PHMM during arthroscopic ACL reconstruction, and to describe a diagnostic algorithm.

Methods

115 patients who underwent arthroscopic ACL reconstruction were enrolled for the study. An anterior and an intercondylar notch visualisation were ordinarily performed. A postero-medial (PM) portal was performed when the instability of the posterior horn was detected. Statistical significance was assessed by a Chi-squared or Fisher's Exact Test for categorical variables, and by a Mann-Whitney U test for continuous variables.

Results

We recorded a 9.6% prevalence of lesions of the peripheral attachment of PHMM. Nine ramp lesions and two hidden lesions were diagnosed. Patients treated within 6 months from injury, revealed a statistically significant correlation with a higher prevalence of these lesions.

Conclusion

Ramp and hidden lesions are very common ACL rupture associated injuries. Our diagnostic algorithm is a valid and safe option to diagnose these kinds of lesions. A correlation between a longer time from injury than 6 months and a reduced prevalence of these lesions was recorded in our population.

Level of evidence

IV.

MRI can accurately detect meniscal ramp lesions of the knee

PURPOSE

Posterior horn meniscal tears are commonly found in conjunction with anterior cruciate ligament (ACL) injury. Some believe tears in the posterior meniscocapsular zone, coined ramp lesions, are important to knee stability. The purpose of this study was to determine whether pre-operative MRI evaluation was able to accurately and reproducibly identify ramp lesions.

METHODS

Three blinded reviewers assessed MRIs twice for the presence of ramp lesions in patients undergoing ACL reconstruction. Sensitivity, specificity, negative predictive value, and positive predictive value for MRI were calculated based on arthroscopic diagnosis of a ramp lesion. Intra-class correlation coefficient was calculated to assess intra- and interobserver reliability of the MRI assessment between the three examiners. Significance was set at p < 0.05.

RESULTS

Ninety patients met inclusion criteria (45 males, 45 females, mean age 28.0 years). Thirteen of these patients had arthroscopy-confirmed ramp lesions, while the other 77 had other meniscal pathology. Sensitivity of detecting a ramp lesion on MRI ranged from 53.9 to 84.6%, while specificity was 92.3-98.7%. Negative predictive value was 91.1-97.4%, while positive predictive value was 50.0-90.0%. Inter-rater reliability between three reviewers was moderate at 0.56. The observers had excellent intra-rater reliability ranging from 0.75 to 0.81.

CONCLUSIONS

This study demonstrates high sensitivity and excellent specificity in detecting meniscal ramp lesions on MRI. Ramp lesions are likely more common and may have greater clinical implications than previously appreciated; the outcomes of untreated lesions must be investigated. Pre-operative identification of ramp lesions may aid clinicians in surgical planning and patient education to improve outcomes by addressing pathology which may have otherwise been missed.

LEVEL OF EVIDENCE

III.

Meniscus tear surgery and meniscus replacement

OBJECTIVE

the menisci are easily injured and difficult to repair. The aim of this study was to analyze the current state of meniscal surgery aimed at preserving morphology and conserving the biomechanics of the knee to prevent joint degeneration.

METHODOLOGY

a search of the electronic medical literature database Medline was conducted, from http://www.ncbi.nlm.nih.gov/pubmed. The search was not limited by language. Candidate articles were identified by searching for those that included the keywords meniscus, surgery, suture, implant, allograft. The limits were included for clinical research and clinical trials. Basic research was not included. The studies selected were evaluated and classified in three different categories: basic science, reconstruction (suture and meniscectomy) and implants (scaffolds and allograft).

RESULTS

the consequences of meniscectomy performed at a young age can lead to a joint cartilage degeneration twenty years later. There are few surgical options for the repair of meniscal injuries in order both to preserve the meniscus and to ensure the long term survival of the knee joint, meniscectomy, repair, suturing the tear, or reconstruction, when a meniscal allograft or synthetic substitute is used to replace the meniscus, but the biomechanical properties of the native meniscus are not reproduced entirely by the scaffolds that exist today.

CONCLUSION

therapies that successfully repair or replace the meniscus are therefore likely to prevent or delay osteoarthritis progression.

Repairing Posteromedial Meniscocapsular Separation: A Technique Using Inside-Out Meniscal Repair Needles

Posteromedial meniscocapsular separation of the knee has received renewed interest, with many articles describing a high incidence in association with anterior cruciate ligament injury. Various techniques have been described to address these lesions using all-inside meniscal repair sutures or using rotator cuff repair instruments through the posteromedial portal. Most orthopaedic surgeons are accustomed to using the "inside-out" meniscal repair technique with a double-armed suture. This technique is cost-effective and, in our opinion, more efficient in repairing such tears. We present our technique of repairing peripheral meniscocapsular lesions using an inside-out meniscal repair system. We believe that this technique is easily reproducible, is less time-consuming, and ensures a good "bite" of the capsular tissue, producing a robust repair.

Fibrous cartilage of human menisci is less shock-absorbing and energy-dissipating than hyaline cartilage

PURPOSE

To test meniscal mechanical properties such as the dynamic modulus of elasticity E* and the loss angle δ at two loading frequencies ω at different locations of the menisci and compare it to E* and δ of hyaline cartilage in indentation mode with spherical indenters.

METHODS

On nine pairs of human menisci, the dynamic E*-modulus and loss angle δ (as a measure of the energy dissipation) were determined. The measurements were performed at two different strain rates (slow sinusoidal and fast single impact) to show the strain rate dependence of the material. The measurements were compared to previous similar measurements with the same equipment on human hyaline cartilage.

RESULTS

The resultant E* at fast indentation (median 1.16 MPa) was significantly higher, and the loss angle was significantly lower (median 10.2°) compared to slow-loading mode's E* and δ (median 0.18 MPa and 16.9°, respectively). Further, significant differences for different locations are shown. On the medial meniscus, the anterior horn shows the highest resultant dynamic modulus.

CONCLUSION

In dynamic measurements with a spherical indenter, the menisci are much softer and less energy-dissipating than hyaline cartilage. Further, the menisci are stiffer and less energy-dissipating in the middle, intermediate part compared to the meniscal base. In compression, the energy dissipation of meniscus cartilage plays a minor role compared to hyaline cartilage. At high impacts, energy dissipation is less than on low impacts, similar to cartilage.

Posteromedial meniscal tears may be missed during anterior cruciate ligament reconstruction

PURPOSE

This study aimed to assess the benefit of using an arthroscopic intercondylar view and a posterior medial viewing portal during anterior cruciate ligament (ACL) reconstruction in the diagnosis of posterior horn of the medial meniscus (PHMM) tears. A secondary objective was to determine clinical and radiological risk factors for the PHMM.

METHODS

Forty-one patients undergoing isolated ACL reconstruction were prospectively evaluated. At ACL reconstruction, the PHMM was assessed using a standard 30° arthroscope in 3 sequential stages: a "classic" anterolateral portal view, an intercondylar view, and a view through a posteromedial portal.

RESULTS

Thirty-nine patients were included (12 female patients and 27 male patients). A posteromedial tear of the medial meniscus was found in 17 patients using the anterolateral portal view. The intercondylar view identified 4 new additional lesions and extensions of 3 previously identified lesions. The posteromedial portal view identified 6 new lesions and 5 extensions of known lesions compared with the anterolateral portal view. Two lesions seen through the posteromedial portal were not identified by either the anterolateral portal view or the intercondylar view.

CONCLUSIONS

Tears of the PHMM may be underdiagnosed by intraoperative assessment using only an anterolateral portal view during ACL reconstruction. The intercondylar view combined with a posteromedial portal aids in the diagnosis of PHMM tears and should be considered in routine ACL reconstruction to assess meniscal status, particularly when the interval from injury to surgery is prolonged.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

The FasT-Fix Repair Technique for Ramp Lesion of the Medial Meniscus

Introduction

This technical note describes a new arthroscopic technique to repair the peripheral attachment lesion of the posterior horn of the medial meniscus. The operation was performed under arthroscopy using a standard anterior portal.

Surgical Technique

A FasT-Fix needle was inserted obliquely close to the tibial plateau and the first implant was inserted into the joint capsule depending on its bending angle underneath the meniscus. The second implant was inserted through 1/3 periphery of the meniscus into the meniscocapsular area. The pre-tied self-sliding knot was tensioned to achieve secure fixation of the posterior meniscal peripheral attachment at the original attachment point.

Materials and Methods

From August 2011 to February 2014, 23 knees were diagnosed as ramp lesion, underwent meniscal repair using FasT-Fix technique.

Results

All patients were followed up for average 14 months. The Lysholm score improved from preoperative 64.4±4.52 to postoperative 91.2±4.60.

Conclusions

We believe that the FasT-Fix technique via the standard anterior portal can be a more convenient and less traumatic alternative for repair of the peripheral attachment lesion of the posterior horn of the medial meniscus in the anterior cruciate ligament deficient knee.

Meniscal translation during knee flexion: what do we really know?

PURPOSE

Translation during knee flexion is a key function of the menisci. The amount of translation displayed by the medial and lateral meniscus during knee flexion, particularly while loadbearing, remains relatively unknown. To address this lack of knowledge, a systematic review of the relevant literature was performed.

METHODS

We performed a literature search for studies in which a primary aim was to report the anterior-posterior translation of the menisci during knee flexion. Data were collected on the characteristics of the sample, the imaging approach, measurement and analysis techniques, and outcome variables. We scored the quality of studies and their reporting using a modified Coleman methodology score with ten criteria, with a maximum possible score of 100.

RESULTS

Twelve full-text studies were retrieved that met the inclusion criteria. Of these, the in vitro studies (N = 4) scored the lowest for methodology (median 44.5), with in vivo studies of healthy knees (N = 4) (median 60) and in vivo comparative studies (N = 4) scoring highest (median 74.5). The evidence from studies with the highest methodology scores (>65) (N = 4) indicate that the lateral meniscus translates more posteriorly than the medial meniscus during flexion. In addition, meniscal translation is influenced by loading, particularly in knee rotation, but not by ACL deficiency, despite greater posterior translation of the medial femoral condyle during flexion.

CONCLUSIONS

The generally low methodological quality of studies suggests that caution is required when interpreting meniscal translation during knee flexion reported in the literature. While the methods for assessing meniscal translation in vivo continue to improve and provide opportunity for clinical implementation, there remains a lack of robust evidence regarding meniscal translation in the healthy knee for comparative purposes. A number of recommendations are made for future studies to address key limitations identified in previous investigations. Additional studies of high methodological quality are required to quantify the relationships between joint loading, joint pathology and meniscal translation during knee flexion.

LEVEL OF EVIDENCE

III.

Hidden lesions of the posterior horn of the medial meniscus: a systematic arthroscopic exploration of the concealed portion of the knee

BACKGROUND

Anterior cruciate ligament (ACL) tears are frequently associated with meniscal lesions. Despite improvements in meniscal repair techniques, failure rates remain significant, especially for the posterior horn of the medial meniscus.

PURPOSE

To determine whether a systematic arthroscopic exploration of the posterior horn of the medial meniscus with an additional posteromedial portal is useful to identify otherwise unrecognized lesions.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

In a consecutive series of 302 ACL reconstructions, a systematic arthroscopic exploration of the posterior horn of the medial meniscus was performed. The first stage of the exploration was achieved through anterior visualization via a standard anterolateral portal. In the second stage, the posterior horn of the medial meniscus was visualized posteriorly via the anterolateral portal with the scope positioned deep in the notch. In the third stage, the posterior horn was probed through an additional posteromedial portal. A χ2 test and logistic regression analysis were performed to determine if the time from injury to surgery was associated with the meniscal tear pattern.

RESULTS

A medial meniscal tear was diagnosed in 125 of the 302 patients (41.4%). Seventy-five lesions (60%) located in the meniscal body were diagnosed at the first stage of the arthroscopic exploration. Fifty lesions located in the ramp area were diagnosed: 29 (23.2%) at the second stage and 21 lesions (16.8%) at the third stage after minimal debridement of the superficial soft tissue layer. The latter type of lesion is called a "hidden lesion." Altogether, the prevalence of ramp lesions in this population was 40%. Meniscal body lesions (odds ratio, 2.6; 95% confidence interval, 1.18-5.18; P < .02) were found to be significantly correlated with a longer delay between injury and surgery.

CONCLUSION

Posterior visualization and posteromedial probing of the posterior horn of the medial meniscus can help in discovering a higher rate of lesions that could be easily missed through a standard anterior exploration. In numerous cases, these lesions were "hidden" under a membrane-like tissue and were discovered after minimal debridement through a posteromedial portal.

Delay in ACL reconstruction is associated with more severe and painful meniscal and chondral injuries

PURPOSE

The goal of our study was to investigate the associations between surgical delay, pain and meniscus, and articular cartilage lesions seen at the time of ACL reconstruction.

METHODS

One hundred and sixty-two consecutive patients who had received ACL reconstruction were recruited. The preoperative International Knee Documentation Committee (IKDC) questionnaires, and cartilage and meniscal lesions seen at the time of surgery were analysed.

RESULTS

Patients with surgery within 12 months were less likely to have meniscus injury (59.8/77.4 %, p = 0.032), and the meniscus injury was more likely to be salvageable. (56.3/36.0 %, p = 0.042). Patients with meniscal tear larger than 10 mm had higher pain intensity than tear <10 mm (mean 6.8/8.2, p = 0.007). Patients older than 35 years of age were more likely to suffer from cartilage injury (76.4/39.1 %, p = 0.004). Patients with cartilage lesions had longer surgical delay (mean 18.9/12.1 months, p = 0.033). The presence of meniscal tear increased the risk of cartilage lesions (p = 0.038, OR = 2.14). Patients with cartilage lesions had a greater pain frequency (mean 6.9/7.7, p = 0.048). Moderate correlation was found between the size of cartilage lesion and the frequency of pain (p = 0.013).

CONCLUSIONS

Increased surgical delay was associated with an increased incidence of meniscus and articular cartilage injuries in patients suffering from ACL tear; also, the meniscus was less likely to be salvageable. The presence of cartilage lesions was associated with an increased frequency of pain. Size of meniscal and cartilage lesions was significantly associated with pain.

What does it take to have a high-grade pivot shift?

The pivot shift is the most specific clinical test to assess pathological knee joint rotatory laxity following ACL injury. This article attempts to describe the anatomic structures responsible for creating a high-grade pivot shift and their potential role in customizing ACL reconstruction. A review of the literature demonstrates that disruption of the secondary stabilizers of anterior translation of the lateral compartment including the lateral meniscus, anterolateral capsule, and IT band contributes to a high-grade pivot shift in the ACL-deficient knee. The morphology of the lateral tibial plateau, including increased posteroinferior tibial slope and small size, can also contribute to high-grade pivot shift. Factors that may decrease the grade of the pivot shift include medial compartment injury, MCL injury, patient guarding, and osteoarthritis. In conclusion, a high-grade pivot shift in the ACL-deficient knee is often associated with incompetence of the lateral soft tissue envelope. Rotatory laxity as assessed by the pivot shift may also be falsely underestimated by concomitant injuries.

LEVEL OF EVIDENCE

IV.