Intra-articular ganglion arising from the meniscofemoral ligament of Humphrey

Prevalence, Biomechanics, and Pathologies of the Meniscofemoral Ligaments: A Systematic Review

Purpose

To systematically review the literature to examine current understanding of the meniscofemoral ligaments (MFLs), their function, their importance in clinical management, and known anatomical variants.

Methods

A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using PubMed, EMBASE, and Cochrane databases. Studies were included if they reported on the biomechanical, radiographic, or arthroscopic evaluation of human MFLs, or if they reported on an anatomical variant. These were then categorized as cadaveric, radiographic, or clinical. Biomechanical, radiographic, patient-reported, and functional outcomes data were recorded.

Results

Forty-seven studies were included in the qualitative analysis, and 26 of them were included in the quantitative analysis. Of these, there were 15 cadaveric, 3 arthroscopic, and 9 radiographic studies that reported on the prevalence of MFLs. Overall, when looking at all modalities, the presence of either the anterior or posterior MFL (aMFL, pMFL) has been noted to be 70.8%, with it being the aMFL 17.4% and the pMFL 40.6%. The presence of both ligaments occurs in approximately 17.6% of individuals. Eleven reported on mean MFL length and thickness. When evaluating mean length in both men and women, the aMFL has been reported between 21.6 and 28.3 mm and the pMFL length in this population is between 23.4 and 31.2 mm. Five reported on cross-sectional area. Nine additional papers report anatomical variants.

Conclusions

This review shows that there continues to be a variable incidence of MFLs reported in the literature, but our understanding of their function continues to broaden. A growing number of anatomic and biomechanical studies have demonstrated the importance of the MFLs in supporting knee stability. Specifically, the MFLs serve an important role in protecting the lateral meniscus and augmenting the function of the posterior cruciate ligament.

Clinical Relevance

Our findings will aid the clinician in both identifying and treating pathologies of the meniscofemoral ligaments.

Signification of the unusual delineation of the anterior meniscofemoral ligament of Humphrey during knee arthro-CT

BACKGROUND

Meniscofemoral ligaments (MFLs) are recognized as stabilizing and protective structures for the posterolateral meniscocondylar compartment of the knee, and as secondary restraints to tibial posterior translation.

PURPOSE AND PATIENTS

We report the 64-row arthro-MDCT findings of 10 patients (8 males, 2 females; mean age 43.8 years) in which the anterior MFL of Humphrey (aMLF) was atypically well delineated by an unusual circumferential effusion of iodine contrast. We discuss a possible physiopathologic mechanism for this effusion, describe the MDCT anatomy of the aMLF and review the literature about the anatomy and physiology of the MFLs.

RESULTS

In each of our ten patients an unusual effusion of articular contrast was found delineating a posterior oblique ligamentar bundle, which was running in front of the posterior cruciate ligament (PCL). This bundle was best appreciated on posterior coronal oblique and sagital MPR views, and was recognized as the aMFL. The finding was associated with a partial tear of the tibial insertion of the posterior horn (PH) of the lateral meniscus (LM) in three patients, and with a partial (two cases) or subtotal (three cases) tear of the PCL in five patients. A swollen-probably oedematous-PCL was found in another patient and in the last case the anomaly was minimal and remained isolated. All patients were treated conservatively.

CONCLUSION

Since the aMFL inserts inferiorly into the posterior horn of the LM and runs in very close anatomic and functional relation with the PCL, we hypothesize that a trauma producing a tear in these structures may also occasionally sufficiently stretch the aMFL to produce a peripheral loosening allowing a circumferential effusion of opacified synovial fluid around the ligament. Our report offers the opportunity to illustrate the "in vivo" anatomy of the aMFL through original unpublished figures. It also contributes to reinforce the literature data concerning the potential fine mechanical role played by the LM-MFLs-PCL complex, in which the centrally located MFLs act laterally as stabilizing and protective structures for the posterolateral meniscocondylar compartment and medially as secondary restraints to tibial posterior translation.

A new symptomatic intra-articular cord-like structure associated with discoid meniscus

We introduce a new, not yet described cord-like structure of the knee of children associated with discoid or enlarged menisci. This structure was responsible for knee pathology (loss of extension) in 3 cases. The patients (5 to 8 years of age) complained of knee pain without skeletal abnormality or trauma. Magnetic resonance imaging revealed enlarged or discoid lateral menisci. The patients showed increasing limp with limited range of motion. Lack of extension was between 10 degrees and 45 degrees and continued under anesthesia. During arthroscopy, the menisci and the anterior and posterior cruciate ligaments (ACL, PCL) showed no abnormality other than the variant of the lateral meniscus described above. A tight cord-like structure was imposed, running laterally along the ACL. This cord-like structure was attached to the lateral femoral intercondylar area and the posterior horn region of the lateral meniscus in a sail-like shape. Two knees showed abnormal mobility of the lateral meniscus, tending to luxate. The ligamentous structure was cut stepwise lateral to the ACL, leaving the entire lateral meniscus undisturbed. Finally, full extension was achieved. Examination 7 to 27 months after surgery showed asymptomatic knees. This ligamentous structure is an important differential diagnosis to symptoms usually referred to as meniscus pathology. The appropriate treatment involves dissection. A loss of meniscal tissue followed by development of osteoarthritis can be prevented.