• anterior cruciate ligament
• anomalous insertion
• lateral meniscus

• Humans
• Female
• Adolescent
• Anterior Cruciate Ligament/abnormalities
• Anterior Cruciate Ligament/surgery
• Anterior Cruciate Ligament/diagnostic imaging
• Menisci, Tibial/diagnostic imaging
• Menisci, Tibial/abnormalities
• Menisci, Tibial/surgery
• Arthroscopy
• Anterior Cruciate Ligament Reconstruction/methods
• Magnetic Resonance Imaging

• UL1 TR001863 NCATS NIH HHS

• Humans
• Female
• Child, Preschool
• Menisci, Tibial/surgery
• Menisci, Tibial/diagnostic imaging
• Menisci, Tibial/abnormalities
• Arthroscopy/methods
• Regeneration
• Magnetic Resonance Imaging
• Anterior Cruciate Ligament Reconstruction

• Humans
• Nail-Patella Syndrome/complications
• Nail-Patella Syndrome/diagnostic imaging
• Nail-Patella Syndrome/pathology
• Knee Joint
• Femur/diagnostic imaging
• Femur/surgery
• Femur/pathology
• Epiphyses
• Meniscus

• Agenesis of ACL
• Aplasia of ACL
• Congenital ACL deficiency
• Congenital absent ACL

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.

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.

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.

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.

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

To gain a greater understanding of anomalous insertions of the anterior horn of the medial meniscus through evaluation of a rare case and a review of the existing literature on medial meniscus malformations.

This report describes a 26-year-old man with an anomalous insertion of the anterior horn of the medial meniscus combined with symptomatic hypertrophy of the anterior horn and a synovial cyst. We also conducted a review of the existing literature on medial meniscus malformations using five major scholarly literature databases and search engines.

The literature review revealed that the incidence of anomalous insertions of the anterior horn of the medial meniscus is 0.5% to 2.8%. Not all patients undergo surgical excision; some are only symptomatically treated. In our patient, the arthroscopic view was consistent with the imaging characteristics. No special operation was performed to treat the anomalous insertion. At the 18-month follow-up, the patient had no symptom recurrence and had returned to practicing sports.

The pain during hyperextension in our patient was caused by a cyst and anterior horn hypertrophy. If the symptoms in such cases are not caused by the anomalous insertion, no special treatment is needed.

• Anomalous insertion
• case report
• hypertrophy of anterior horn
• literature review
• malformation
• medial meniscus
• synovial cyst

• Anterior cruciate ligament agenesis
• Anterolateral meniscofemoral ligament
• Reconstruction
• Ring lateral meniscus

Hypoplasia of bilateral cruciate ligaments is a rare congenital malformation. The diagnosis of such diseases and indications for the various treatment options require further analysis and discussion.

The patient is a 26-year-old Chinese woman who has been suffering from knee pain since the age of 8 years, 2-3 episodes a year. Three years ago, due to the practice of advanced yoga poses, the frequency of left knee pain increased, requiring prompt medical treatment. Magnetic resonance imaging demonstrated an absence of both anterior and posterior cruciate ligaments of both knees with abnormal posterior tilting of the tibial plateau. Bilateral subluxation of the knee joint was also found, therefore tibial osteotomy was performed. The patient reported at the 24 mo follow-up that the frequency of pain and instability had been reduced and function restored.

Osteotomy may be an effective method to treat patients with congenital cruciate ligament deficiency with posterior tibial plateau tilting. The diagnosis of congenital cruciate ligament deficiency shall be based on the combination of patient’s medical history, clinical manifestations, and findings from imaging to avoid possible misdiagnosis. Based on the symptoms, frequency of attacks, and intent of the individual, appropriate treatment options shall be identified.

• Congenital
• Dysplasia
• Cruciate ligament
• Congenital deformity
• Osteotomy
• Case report

Congenital absence of the cruciate ligament is a rare condition with a prevalence of 0.017 per 1000 live births. This study reports a case of congenital absence of the anterior and posterior cruciate ligaments of the left knee associated to a type 1A fibular hemimelia, and a contribution to the existing hypotheses on knee ligaments development. According to medical literature the anomaly begins to develop around the seventh–eighth week of pregnancy. Patients with a cruciate ligament agenesis will often need a knee replacement at one point in their lives.

Anatomical variations of the meniscus are a common anomaly that knee surgeons frequently encounter. However, anomalies of the anterior horn of the lateral meniscus (AHLM) are extremely rare. In this report, we present a newly discovered anomaly of the AHML: an anterolateral meniscofemoral ligament is described with clinical features and radiographic and arthroscopic findings.

• Knee
• Lateral meniscus
• Meniscofemoral ligament

• Hypoplasic anterior cruciate ligament
• Knee
• Malformations
• Ring-shaped meniscus

• Anterior Cruciate Ligament/abnormalities
• Anterior Cruciate Ligament/pathology
• Female
• Humans
• Joint Instability/diagnosis
• Joint Instability/rehabilitation
• Knee Joint/abnormalities
• Knee Joint/pathology
• Menisci, Tibial/abnormalities
• Menisci, Tibial/pathology
• Middle Aged
• Treatment Outcome