Posterior Horn Of The Medial Meniscus Research Articles

Association of meniscal tears with cruciate ligament injuries

Aim: To find the association of meniscal tears with isolated and combined cruciate ligament injuries, grades of injury, time of injury and type of injury. Method: Magnetic resonance (MR) imaging of 240 patients with knee pain who diagnosed with anterior cruciate ligament (ACL) and Posterior Cruciate Ligament (PCL) injury by arthroscopy were studied. Results: Road and traffic accidents (RTA) caused in 80.4% of cases. A total of 192 patients (80%) with isolated ACL involvement, seven patients (2.9%) with isolated PCL involvement, and 41 patients (17%) with combined ACL and PCL involvement. In cases with ACL involvement (n=192), 17 patients (8.8%) had grade 1 injury: sprain, 82 patients (42.7%) had grade 2/3 injury: partial tear and 93 patients (48.4%) had grade 4 injury: complete tear. Among partial ACL tear, lateral meniscus involvement was predominant in 45 patients (54.8%), whereas medial meniscus was involved in 26 patients (31.7%) and normal meniscus was observed in 19 patients (23.1%). In lateral meniscus, the anterior horn was majorly involved 36 patients (80%) as compared to posterior horn in 15 patients (33.3%). Conclusion: The present study indicates that the anterior horn of the lateral meniscus was predominantly involved in patients with isolated ACL and combined injury of ACL and PCL. The posterior horn of the medial meniscus was more commonly involved in chronic injury of ACL, whereas the posterior horn of the lateral meniscus was involved in acute ACL injury. Early ACL reconstruction is recommended for the prevention of secondary meniscal tears.

Adjuvant Medial Collateral Ligament Release at the Time of Knee Arthroscopy: A Controlled Percutaneous Technique

The posterior horn of the medial meniscus can be challenging to view during arthroscopy because the medial femoral condyle obstructs vision, especially in tight medial compartments. Previous studies have described techniques for improving access, one being a percutaneous medial collateral ligament (MCL) release. This technique allows for increased medial compartment space, which offloads a tight medial compartment, minimizes iatrogenic chondral injury, incomplete meniscal resection, uncontrolled MCL rupture, and allows for accurate diagnosis and management. Studies have proven the safety of the controlled percutaneous MCL release, with no significant postoperative MCL laxity on stress views, no subjective patient instability, fewer iatrogenic cartilage lesions, and no saphenous neurovascular injury. Furthermore, retrospective studies have shown improved postoperative patient-reported outcomes with a controlled percutaneous MCL release in comparison to standard of care without a release. We hypothesize that a controlled percutaneous release of the MCL effectively alleviates some of the pressure within the medial compartment, which could potentially explain the improved postoperative clinical outcomes. This technique also facilitates improved visualization, a decreased risk of iatrogenic chondral injury, and a more complete meniscal resection. The purpose of this Technical Note is to describe our surgical technique and provide surgical pearls for a controlled percutaneous MCL release during knee arthroscopy.

Periodical assessment of four horns of knee meniscus using MR T2 mapping imaging in volunteers before and after amateur marathons

To observe the changes and recovery of T2 values of menisci in amateur marathon participants at different times, and to examine the effect of marathon exercise on meniscal microstructure. Twelve healthy marathon volunteers were recruited continuously, including 5 males and 7 females, with mean (± SD) age of 27.5 ± 5.2 years. The body mass indices (BMIs) ranged from 17.6 to 27.2 kg/m2, with a mean of 21.9 ± 2.5 kg/m2. The 24 knee joints were scanned using a 3 T MR scanner at 1 week before the event, and at 12 h and 2 months after the event. T2 values of the anterior horn of the medial meniscus (MMAH), posterior horn of the medial meniscus (MMPH), anterior horn of the lateral meniscus (LMAH), and posterior horn of the lateral meniscus (LMPH) were measured by drawing the regions of interest (ROIs) on the T2 map images. Wilcoxon sign rank test was used to compare the T2 values between 1 week before and 12 h after the event, and between 1 week before and 2 months after the event in each anatomical region, respectively. The T2 values of the menisci at 12 h after the event were significantly higher (P < 0.05) than those at 1 week before the event. No statistically significant differences in the T2 values of the menisci were found between 2 months after and 1 week before the event (P > 0.05). The T2 values of MMAH, MMPH, LMAH, and LMPH showed a trend of "increasing first and then decreasing" over time, suggesting that the T2 values may reflect meniscal microstructure in amateur marathon runner.

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.

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 natural long-term course of unrepaired ramp lesion: a retrospective analysis of 28 patients followed for at least 20 years

Objectives:Ramp lesion is a specific type of injury, located in the posterior horn of the medial meniscus. The purpose of the study was to evaluate the complications for meniscal ramp lesions left in situ during ACL reconstruction, after more than 20 months of follow up.Methods:All patients who underwent arthroscopic ACLR between January 1998 and December 2000 were evaluated retrospectively. Surgery was performed by the same surgeon. In case of a stable vertical tear, i.e. without instability, the lesion was left in situ, without suture or debridement. The following parameters were examined: demographics; history and clinical findings including time between injury and surgery, side-to-side laxity, pivot shift; knee function and activity by Lysholm score, subjective IKDC, KOOS and Tegner activity scale; and progression to bucket handle. We established two groups: the bucket handle group versus the no bucket handle group.Results:A total of 716 patients underwent a primary ACLR during this period. The overall incidence of ramp lesions in the study population was 5.4% (39 ramp lesions in 716 patients). Mean follow-up time was 262.1 (± 10.5) months. Bucket handle tear of the medial meniscus occurs in 21.4% of our population, with an average lead time of 99 (± 50) months, and a concentration of injuries between 96 and 156 months. The postoperative scores significantly improved for the entire population at more than 20 years of follow-up (p <0.0001), except for the Tegner score (p = 0.3424). Functional scores and side-to-side laxity were the same for the two groups. No risk factors were identified.Conclusion:There is a high incidence of bucket-handle injury after ACL surgery with a residual ramp lesion (21.4%). This high rate is only found in series with a long follow-up, since these lesions appear between 8 and 12 years after the first surgery.

Biomechanical Comparison of Meniscal Allograft Root Fixation Techniques: Anterograde Interference Bone Plug Fixation Yields Favorable Results Compared to Transosseous Suture Fixation Alone

PurposeTo compare the biomechanical properties of 2 different fixation techniques (interference bone plug fixation vs transosseous suture fixation) of the posterior horn of the medial meniscus using a porcine model.MethodsTwenty-six matched pairs of fresh-frozen juvenile domestic porcine knees were used in this study. Specimens were randomly distributed among 3 groups: (1) native meniscus groups, (2) interference fixation, and (3) transosseous suture fixation. In each group, the posterior segments of the tested medial menisci were gripped with the freeze clamps and fixed to the tensile testing machine. Samples were preconditioned, followed by cyclic tension-relaxation for 1000 cycles between 10 and 30 N at 0.5 Hz and finally pulled to failure at a rate of 0.55 mm/s. The cyclic elongation, stiffness to failure, mode, and ultimate load to failure were recorded.ResultsThere was no significant difference in ultimate load to failure between the interference fixation (169.71 ± 71.98 N) and transosseous suture fixation (222.73 ± 72.40 N) groups (P = .118), both were significantly less than that of the native meniscus (405.46 ± 95.62) (P < .001). Interference fixation displayed cyclic elongation (1.04 ± 0.71 mm) and stiffness (69.10 ± 25.8 N/mm) that were not significantly different from the native meniscus tissue (0.78 ± 0.53 mm and 83.1 ±26.28 N/mm) (P = .359 and P = .224), in comparison to transosseous suture fixation, which did show increased cyclic elongation (1.85 ± 1.44 mm) (P = .047) and decreased stiffness (34.72 ± 10.2 N/mm) (P < .001).ConclusionInterference fixation of the posterior horn of the medial meniscus has superior cyclic elongation and stiffness when compared to transosseous suture fixation. Interference fixation and the native meniscus model have a similar stiffness and cyclic elongation.Clinical RelevanceThe significance of our study is that using interference fixation for meniscal allograft transplantation has the potential to reduce short term surgical failures as well as long term complication rates.

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.

Application of exposure enhancement technique combined with femoral condyle pushing technique in repairing the posterior horn of the medial meniscus under knee arthroscopy.

Objectives:To investigate the clinical efficacy of exposure enhancement technique and femoral condyle pushing technique applying in the posterior horn of the medial meniscus of the knee.Methods:From January 2016 to June 2019, 52 patients with injury in the medial meniscus treated in our department were selected. The horizontal tear of the posterior horn of the medial meniscus was repaired by exposure enhancement technique and femoral condyle pushing technique using the meniscus suture system. Postoperatively, the efficacy was evaluated using the Lysholm scoring system.Results:These 52 patients were all followed up for 3~18 months, with an average of 12.5 ± 7.3 months. The pain and activity of all patients were significantly improved compared with those before surgery.Conclusion:Exposure enhancement technique and femoral condyle pushing technique in the repair of the posterior horn of the medial meniscus presents satisfactory efficacy. It can improve the pain and activity of the knee, and enhance the stability of residual meniscus. Therefore, it is worth promoting.

Comparative study between isolated medial meniscus root repair versus open-wedge high tibial osteotomy versus combined approach in patients with root tears, 2-year follow-up

Background Medial meniscus root tears usually lead to loss of hoop tension of the meniscus and result in high-contact pressure in the medial compartment of the knee. Surgical management of those types of tears is mandatory to restore hope tension and to save medial compartment. This study was done to evaluate the necessity of medial root repair with high tibial osteotomy (HTO) for treatment of medial meniscus root tears. Patients and methods This is a prospective comparative study over 60 patients with medial meniscal root tears. The patients were classified randomly into three groups. The first group (group A) was treated with isolated medial meniscus posterior root tear repair (n=20). The second group (group B) was treated with isolated open-wedge high HTO (n=20). The third group (group C) was treated using combined medial meniscal root repair with high tibial open-wedge osteotomy (n=20). A clinical evaluation was made using range of motion (ROM) and pain assessment. Functional evaluation was done using Lysholm score and Hospital for Special Surgery score. Radiological evaluation was done using follow-up standing Lyon–Schuss films. Results Regarding the patients’ reported outcome measures, one-way analysis of variance was calculated to compare means between the three groups. The results of isolated root repair were the worst and there was no statistically significant difference between groups B and C. Conclusion Results recommend isolated HTO as a solo fast-attack procedure with reliable durable clinical and radiological outcomes for the treatment of root tears of the posterior horn of the medial meniscus.

Morphological changes in the superficial medial collateral ligament on knee MR imaging: association with medial meniscal extrusion and posterior root medial meniscus abnormality.

To assess the association between morphological changes in the superficial medial collateral ligament and meniscal extrusion with medial meniscus posterior root tear. From January 1, 2018, to December 31, 2019, 124 patients who underwent knee MRI within 90days prior to knee surgery and whose medial meniscus surgically proved intact, with posterior root tear or posterior horn tear, were enrolled. Two radiologists who were blinded to the surgical results assessed the morphological changes in the superficial medial collateral ligament, including thickness, bowing angle, and presence of signal intensity alteration, and medial meniscus extrusion, according to the presence of tears in the posterior root of the medial meniscus or posterior horn of the medial meniscus using the chi-square test, one-way ANOVA, and Cohen's kappa test. Thirty-six posterior root tears, 31 posterior horn tears, and 57 intact medial menisci were observed surgically. The mean values of thickness showed no significant differences among the three groups. The bowing angle was significantly higher in the posterior root tear than in the posterior horn tear (reader 1 = 0.001, reader 2 = 0.002) and normal meniscus groups (readers 1 and 2 < 0.001). The percentage of superficial medial collateral ligament signal intensity alteration and meniscal extrusion was highest in the group with posterior root of the medial meniscus tear (80.6% and 94.4%, respectively) and lowest in the group with normal medial meniscus (17.5% and 10.5%, respectively). Morphological changes in the superficial medial collateral ligament and meniscal extrusion were associated with medial meniscus posterior root tears.

Évolution naturelle à long terme d’une lésion de la rampe non réparée : analyse rétrospective de 28 patients suivis pendant au moins 20 ans

Ramp lesion is a specific type of injury, located in the posterior horn of the medial meniscus. The purpose of the study was to evaluate the complications for meniscal ramp lesions left in situ during ACL reconstruction, after more than 20 of follow-up. All patients who underwent arthroscopic ACLRs between January 1998 and December 2000 were evaluated retrospectively. Surgery was performed by the same surgeon. In case of a stable vertical tear, i.e. without instability, lesion was left in situ, without suture or debridement. The following parameters were studied: demographics; history and clinical findings including time from injury to surgery, side-to-side laxity, pivot shift; knee and activity function by Lysholm score, subjective IKDC, KOOS and Tegner activity scale; and evolution to bucket handle. We defined two groups: bucket handle group versus no bucket handle group. A total of 716 patients underwent a primary ACLR during this period. The overall incidence of ramp lesions in the study population was 5.4% (39 ramp lesions in 716 patients). Mean follow-up time was 262.1 (± 10.5) months. The occurrence of medial meniscus bucket handle represented 21.4% of our population, with an average delay of 99 (± 50) months, and a concentration of this injury between 96 and 156 months. The postoperative scores were significantly improved for the whole population at more than 20 years of follow-up ( P < 0.0001), except for the Tegner score ( P = 0.3424). Functional scores and side-to-side laxity was the same for the two groups. No risk factors were identified. There is a high incidence of bucket-handle injury after ACL surgery with a ramp lesion left in place (21.4%). This high rate is only found in series with a long follow-up, since these lesions appear between 8 and 12 years after the first surgery.

Meniscal Root Repair With Mini-Open Medial Collateral Ligament Release

Meniscal root repair is becoming more common with increasing knowledge regarding the function of the meniscal root and its role in long-term joint preservation, as well as improved surgical techniques and instrumentation. Despite this, adequate visualization of the posterior horn of the medial meniscus may be challenging, particularly in those with tight medial compartments. Instrument handling and attempt to visualize and repair the meniscal tear may lead to iatrogenic chondral injuries in these instances. We describe our preferred technique for improved visualization via mini-open release of the distal medial collateral ligament that allows for increased joint distension, increased access to the posterior horn of the medial meniscus, and the ability to repair the released medial collateral ligament.

Diagnosis of medial meniscal ramp lesion is difficult by pre-operative magnetic resonance imaging evaluation and needs a methodical arthroscopic exploration

BackgroundMeniscal ramp lesion (RL) is the peripheral lesion of the posterior horn of the medial meniscus (PHMM) associated with anterior cruciate ligament (ACL) tear. The purpose of this study was to evaluate the accuracy of pre-operative magnetic resonance imaging (MRI) evaluation in diagnosing RL and to identify whether the difficulty in diagnosis differs depending on the location of RL. MethodsACL-injured patients undergoing ACL reconstruction from January 2017 to January 2019 were enrolled. A methodical arthroscopic exploration to identify RL was conducted intra-operatively using three steps, namely, the anterior visualization step, the inter-condylar visualization step, and the posteromedial step. The location of the RLs was evaluated and classified into two types as follows: Red-red zone (RR) - a meniscal tear of the red-red zone of the PHMM. Menisco-capsular junction (MCJ) - a lesion at the menisco-capsular junction of the PHMM, which is more peripheral than RR. Furthermore, the accuracy of 1.5-T MRI evaluation to diagnose RL by two testers using sagittal proton-density fat-saturated images was calculated. ResultsOf the 81 patients enrolled, 11 had RL: 5 cases each were at the MCJ and RR, and 1 case was at both locations. The sensitivity of MRI for detecting RL was 27.3–45.5%, whereas the specificity was 84.3–95.7% in total. The sensitivity of MRI in detecting RL at the RR and MCJ was 40.0–80.0%, 0–20.0%, respectively. The intra-observer reliability of the MRI evaluation was moderate (κ coefficient: 0.40–0.46), while the inter-observer reliability was fair to moderate (κ coefficient: 0.27–0.41). ConclusionsA low sensitivity of the MRI in detecting RL at the MCJ was observed, and the reliability of the MRI evaluation for diagnosis of RL was not high. Therefore, methodical arthroscopic exploration is essential to diagnose RL even when it is not suspected on pre-operative MRI.

Arthroscopic incidence of lateral meniscal root avulsion in patients with anterior cruciate ligament injury

BackgroundTo arthroscopically evaluate the incidence of lateral meniscal root avulsion (LMRA) and associated intra-articular injuries in patients undergoing anterior cruciate ligament (ACL) reconstruction.Materials and MethodsFrom April 2014 to March 2017, 532 consecutive patients were diagnosed as having an ACL injury and underwent arthroscopic ACL reconstruction. The diagnosis of LMRA was made arthroscopically. The effects of gender, activity, grade of laxity, time from injury, and concomitant meniscal lesions were analyzed.ResultsAmong 532 patients, 497 (93.4%) underwent primary ACL reconstruction and 35 (6.5%) underwent revision procedures. 383 were acute or subacute injuries (less than 6 months from injury to surgery) and 149 chronic (more than 6 months). Average age was 30.4 years (DS: ± 11.04); there were 422 (79.3%) males and 110 (20.6%) females. A LMRA associated with the ACL injury was detected in 72 cases (13.5%), with a significant prevalence observed in males ({chi ^2} = 4.65; P = 0.031, statistically significant). In the 149 patients with a chronic injury, 27 patients had LMRA (18.1%), while 45 of the 383 patients with an acute or subacute injury had LMRA (11.7%). There was a tendency, albeit not significant ({chi ^2} = 3.721; P = 0.054), for the prevalence to increase with time since the initial ACL injury. LMRA was significantly associated ({chi ^2} = 7.81; P = 0.006) with a meniscocapsular tear of the posterior horn of the medial meniscus (ramp lesion). No other significant associations, such as with severity of A-P translation (as measured by KT-2000) or activity level, were detected.ConclusionLMRA is a relatively common injury associated with both acute and chronic ACL tears. A relatively high incidence in cases of chronic ACL insufficiency suggests that LMRAs do not heal spontaneously or that they may appear with time, even when absent at the time of the initial injury.Level of evidenceLevel III, cross-sectional study.

The accuracy of MRI for the diagnosis of ramp lesions.

To assess the diagnostic accuracy of MRI in diagnosing ramp lesions in patients with an acute lesion of the anterior cruciate ligament (ACL). All consecutive patients over 15years 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 14years 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). 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). The complete fluid filling is the only significant pathological MRI sign for ramp lesions, with moderate accuracy.

Ramp Lesion Subtypes: Prevalence, Imaging, and Arthroscopic Findings in 2156 Anterior Cruciate Ligament Reconstructions

Background: Ramp lesions are defined as a particular type of injury within the posterior horn of the medial meniscus and its meniscocapsular attachments. Five subtypes have been described: type 1, meniscocapsular lesion; type 2, partial superior lesion; type 3, partial inferior lesion or hidden type; type 4, complete tear in the red zone; and type 5, complete double tear. Purpose: (1) To determine the prevalence of different subtypes of ramp lesions in patients undergoing arthroscopic anterior cruciate ligament reconstruction (ACLR). (2) To describe the characteristics of ramp lesions based on imaging and diagnostic arthroscopy. Study Design: Cross-sectional study; Level of evidence, 3. Methods: All patients who underwent arthroscopic ACLRs between November 2015 and November 2018 by 2 senior surgeons at 1 institution were evaluated retrospectively (1) to describe the subtypes of ramp lesions diagnosed intraoperatively using transnotch arthroscopic exploration of the posteromedial compartment and (2) to look for any factors significantly associated with these subtypes. The following parameters were studied: demographics; history and clinical findings including time between injury and surgery, side-to-side laxity, and pivot shift; lesions missed on magnetic resonance imaging (MRI) scans and medial proximal tibial bone contusion visible on MRI scans; and arthroscopic confirmation of ramp lesion (ie, prevalence), associated lateral meniscal tear, or medial chondral tear. Results: Out of 2156 primary or revision arthroscopic reconstructions, 334 ramp lesions were confirmed, giving a prevalence of 15.5%. The subtype distribution was as follows: type 1, 47.9%; type 2, 4.8%; type 3, 11.4%; type 4, 28.7%; type 5, 7.2%. Multivariate analysis showed that gross pivot shift was significantly associated with complete ramp tears (odds ratio, 4.8; 95% CI, 1.7-17.2). Hidden lesions (type 3, inferior partial tear in the red zone) were the most likely to be missed on preoperative MRI (45.9%). Conclusion: In a population undergoing ACLR, the prevalence of ramp lesions was 15.5%. Among the subtypes of ramp lesion, the most common was a meniscocapsular junction tear (type 1). Partial inferior tears (type 3) were the most likely to be missed on preoperative MRI scans. Gross pivot shift was significantly associated with complete ramp tears (types 1, 4, and 5).

The PCL Envelope Lack Sign (PELS) Is a Direct Arthroscopic Sign of Chronic Posterior Cruciate Ligament Insufficiency

Purpose: To present the arthroscopic “PCL envelope lack sign” (PELS) and to calculate its diagnostic characteristics in chronic PCL insufficiency. Methods: Recordings of knee arthroscopies performed in a single clinic between April 2015 to March 2020 were retrospectively evaluated, searching for the “PCL envelope”. It was defined as a “soft tissue cuff coursing around the PCL tibial attachment, visible with the arthroscope positioned between the PCL, medial femoral condyle and posterior horn of the medial meniscus at the level of its shiny white fibers”. PELS was defined as “the PCL adhering to the proximal tibia adjacent to the medial meniscal posterior root attachment, inability to observe the normal space between the PCL and posterior tibia and no soft tissue cuff around the PCL tibial attachment”. Inclusion criteria were possibility to evaluate the PELS presence on recordings. Patients who underwent PCL reconstruction were assigned to the study group. The rest of the patients were controls. Criteria to operate on symptomatic PCL patients were at least 5 mm of posterior instability in physical examination and at least 6 months post-injury. Results: Out of 614 available recordings, 592 patients (205 females, 387 males; mean age 45.2 years, SD = 14.36, range 14–81) were included: 38 in the study group and 554 in the control group. In the study group, PELS was positive in 36 of 38 cases (94.7%). In the control group, PELS was negative in 554 PCL-efficient patients (100%). Calculated PELS sensitivity was 94.7%, specificity 100%, positive predictive value 100%, negative predictive value 99.6%. The PELS was present significantly more often in PCL-insufficient patients, p &lt; 0.001. Conclusions: The PCL envelope lack sign was found to be a highly effective tool to arthroscopically confirm chronic PCL insufficiency, and should be considered a direct sign of chronic posterior knee instability.

Medial Meniscal Ramp Lesion Repair Through Anterior Portals Using a Medial Collateral Ligament Pie-Crusting Technique

Ramp injury, that is, injury to the peripheral attachment of the posterior horn of the medial meniscus, often requires additional surgery during anterior cruciate ligament (ACL) reconstruction. Diagnosis and treatment of ramp lesions are important because unrepaired ramp lesions could cause risk to the reconstructed ACL because of anteroposterior and external rotation laxity, whereas acute rupture or chronic deficiency of the ACL could also cause ramp lesions because of instability. Ramp lesions are difficult to diagnose and treat from the anterior compartment during arthroscopy. Typically, this repair requires technically demanding skills and is performed from the posterior portal using a suture hook under visualization with the arthroscope through the intercondylar notch. Inexperienced surgeons often struggle with using the posterior portal and the suture hook. Our all-inside repair technique using the FasT-Fix system (Smith & Nephew, Andover, MA) under direct visualization from the anterior compartment accompanied by a medial collateral ligament pie-crusting technique facilitates repair of ramp lesions without causing medial instability.

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.