Medial meniscal lesions increase antero-posterior laxity in knees with anterior cruciate ligament injury

PURPOSE

The aim of this study was to quantify the impact of concomitant meniscal lesions on knee laxity using a triaxial accelerometer in a large population of patients affected by anterior cruciate ligament (ACL) injury.

METHODS

A total of 326 consecutive patients (261 men and 65 women, mean age 31.3 ± 11.3) undergoing primary ACL reconstruction, were preoperatively evaluated through Lachman and pivot shift tests using a triaxial accelerometer to quantify knee laxity. An analysis based on the presence of meniscal tears assessed during surgery was performed to evaluate the impact of meniscal lesions on knee laxity.

RESULTS

The anterior tibial translation (Lachman test) presented significantly higher values in patients with medial meniscal lesions (7.3 ± 1.7 mm, p = 0.049) and both medial and lateral meniscal lesions (7.7 ± 1.6 mm, p = 0.001) compared to patients without concomitant meniscal lesions (6.7 ± 1.3 mm). Moreover, patients with both medial and lateral meniscal lesions presented significantly higher values of anterior tibial translation compared to patients with lateral meniscal lesions (p = 0.049). No statistically significant differences were found between the groups in terms of tibial acceleration (pivot shift test).

CONCLUSION

This study demonstrated that the contribution of concomitant meniscal lesions to knee laxity can be objectively quantified using a triaxial accelerometer in ACL-injured knees. In particular, medial meniscus lesions, alone or in association with lateral meniscus lesions, determine a significant increase of the anterior tibial translation compared to knees without meniscus tears.

LEVEL OF EVIDENCE

Level IV.

Changes in Knee Joint Mechanics After Medial Meniscectomy Determined With a Poromechanical Model

The menisci play a vital role in the mechanical function of knee joint. Unfortunately, meniscal tears often occur. Meniscectomy is a surgical treatment for meniscal tears; however, mechanical changes in the knee joint after meniscectomy is a risk factor to osteoarthritis (OA). The objective of this study was to investigate the altered cartilage mechanics of different medial meniscectomies using a poromechanical model of the knee joint. The cartilaginous tissues were modeled as nonlinear fibril-reinforced porous materials with full saturation. The ligaments were considered as anisotropic hyperelastic and reinforced by a fibrillar collagen network. A compressive creep load of ¾ body weight was applied in full extension of the right knee during 200 s standing. Four finite element models were developed to simulate different meniscectomies of the joint using the intact model as the reference for comparison. The modeling results showed a higher load support in the lateral than medial compartment in the intact joint, and the difference in the load share between the compartments was augmented with medial meniscectomy. Similarly, the contact and fluid pressures were higher in the lateral compartment. On the other hand, the medial meniscus in the normal joint experienced more loading than the lateral one. Furthermore, the contact pressure distribution changed with creep, resulting in a load transfer between cartilage and meniscus within each compartment while the total load born by the compartment remained unchanged. This study has quantified the altered contact mechanics on the type and size of meniscectomies, which may be used to understand meniscal tear or support surgical decisions.

Post-traumatic Articular Cartilage Lesions Increase at Second-look Arthroscopy Following Primary Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) reconstruction (ACLR) after ACL rupture improves the instability of the knee joint and decreases mechanical stress to the meniscus and articular cartilage. However, there are reports that post-traumatic osteoarthritis (PTOA) is observed over time following ACLR. In this study, we assessed changes in cartilage lesions by arthroscopic findings following anatomical double-bundle ACLR and at post-operative second-look arthroscopy about 14 months later. We retrospectively evaluated 37 knees in cases with patients <40 years of age who had undergone an anatomical double-bundle ACL reconstruction <1 year after ACL rupture injury from March 2012 to December 2016. Clinical results and arthroscopic cartilage/meniscal lesion were evaluated and compared between a cartilage lesion-detected group and intact-cartilage group. Surgery improved anteroposterior laxity and other clinical measures; however, cartilage lesions were detected at 11 sites during ACLR and at 54 sites at second-look arthroscopy. The periods from injury to second-look arthroscopy and from ACLR to second-look arthroscopy were significantly longer in the cartilage-lesion group (n=23) than in the intact-cartilage group (n=14). Conversely, 96% of meniscal damage observed during ACLR was cured at the time of second-look arthroscopy. Knee articular cartilage lesions after ACL rupture cannot be completely suppressed, even using the anatomical ACL reconstruction technique. This study suggested that articular cartilage lesions can progress to a level that can be confirmed arthroscopically at approximately 17 months after ACL injury. Therefore, in ACLR patients, the possibility of developing knee articular cartilage lesions and PTOA should be considered.

Percutaneous injections of Platelet rich plasma for treatment of intrasubstance meniscal lesions

INTRODUCTION

management of intrasubstance meniscal lesions is still controversial. Intrasubstance meniscal lesions can lead to reduced sports activity and meniscal rupture. Physical therapy is often not satisfactory. Therefore new treatment methods are requested. Platelet Rich Plasma (PRP) has the ability to regenerate tissue; this was proved in several experimental studies. Whether percutaneous injections of PRP are effective in intrasubstance meniscal lesions is unknown. We hypothesize that percutaneous PRP injections lead to pain relief and halt of progression on MRI over 6 months in patients with grade 2 meniscal lesions.

MATERIALS AND METHODS

ten recreational athletes with intrasubstance meniscal lesions (grade II according to Reicher) proven by MR-Imaging (MRI) were treated by percutaneous injections of PRP in the affected meniscal area. Three sequential injections in seven day intervals were performed in every patient. All injections were performed with image converter. Follow-up MRI was done six months after last injection in every patient. Level of sports activity and amount of pain at athletic loads according to numeric rating scale (NRS-11) were noted in each patient before injections and at the time of follow up MRI after six months. The t-test was used to determine statistical differences.

RESULTS

four of ten patients (40%) showed decrease of meniscal lesion in follow up MRI after six months. Nine of ten patients (90%) complained about short episodes of heavy pain after the injections with average NRS-Score of 7.9 at daily loads after the last injection. Six of ten patients (60%) showed Improvement of NRS-Score at final follow up. Average NRS-Score improved significantly (p=0.027) from 6.9 before injections to 4.5 six month after treatment. Six of ten patients (60%) reported increase of sports activity compared to the situation before injections. In four patients (40%) additional surgical treatment was necessary because of persistent knee pain or progression of meniscal lesion.

CONCLUSIONS

percutaneous injections of PRP have the ability to achieve pain relief and halt of progression on MRI over 6 months in patients with grade 2 meniscal lesions. Therefore it could be considered as a treatment option in patients with persisting pain.

LEVEL OF EVIDENCE

IV.

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.