Background
Medial collateral ligament (MCL) and lateral collateral ligament (LCL) injuries of the knee are common. In fact, injury to the MCL is the most common ligamentous knee injury.
The MCL and LCL provide restraint to valgus and varus angulation of the knee, respectively. The MCL has superficial and deep components. The superficial MCL fibers attach proximally to the medial femoral epicondyle and distally to the medial aspect of the tibia, approximately 4 cm distal to the joint line. The deep MCL fibers originate from the medial joint capsule and are attached to the medial meniscus.
The LCL is part of a complex of ligaments collectively named the posterolateral corner (PC). The structures in the PC include the LCL, the popliteofibular ligament, the popliteus ligament, the arcuate ligament, the short lateral ligament, and the posterolateral joint capsule. The LCL is separated from the lateral meniscus by a fat pad (see image below). [1, 2, 3, 4]
The medial and lateral collateral ligaments of the knee. Courtesy of Randale Sechrest, MD, CEO, Medical Multimedia Group.
Related Medscape Drugs & Diseases topics:
Collateral Ligament Pathology, Knee
Knee, Collateral Ligament Injuries (MRI)
Lateral Collateral Knee Ligament Injury
Medial Collateral Knee Ligament Injury
Related Medscape topic:
Resource Center Joint Disorders
Pathophysiology
Medial collateral ligament (MCL) and lateral collateral ligament (LCL) injuries are caused primarily by valgus and varus stress (respectively) to the knee joint. Injuries also can occur to both ligaments with excessive lateral rotation of the knee.
Epidemiology
Frequency
United States
The annual incidence of acute knee injury in the United States is estimated to be 300 cases per 100,000 population. Collateral ligament injuries account for 25% of patients presenting to emergency rooms with acute knee injury. Peak incidence of collateral ligament injuries occurs in adults aged 20-34 years. The National Collegiate Athletic Association (NCAA) injury surveillance system reported 2.1 medial or lateral collateral injuries per 1000 player exposures in games across all NCAA sports over 1 year. [5] Even noncontact sports, such as gymnastics and swimming, can lead to collateral ligament injuries. [6]
International
In a prospective study of Elite Club players in the Union of European Football Associations (UEFA), Lundblad et al found that medial collateral ligament (MCL) injuries accounted for 130 of 4364 registered injuries (3%) occurring among 51 teams over 1-3 full seasons. Ninety-eight MCL injuries (75%) were contact related, with tackling or being tackled representing the most frequent playing-associated contact mechanisms (12% and 29%, respectively). [7]
Mortality/Morbidity
Medial collateral ligament (MCL) and lateral collateral ligament (LCL) injuries can in most individuals be treated successfully with conservative methods. Severe injuries may require surgical intervention and tend to have good outcomes. [2, 8]
Race
There is no known racial predilection for medial collateral ligament (MCL) and lateral collateral ligament (LCL) injuries.
Sex
Unlike anterior cruciate ligament (ACL) injuries, which occur at a higher rate in women, medial collateral ligament (MCL) and lateral collateral ligament (LCL) injuries occur at equal rates in men and women. [6, 9]
Related Medscape Drugs & Diseases articles:
Anterior Cruciate Ligament Pathology
Anterior Cruciate Ligament Injury [Physical Medicine and Rehabilitation]
Anterior Cruciate Ligament Injury [Sports Medicine]
Knee, Anterior Cruciate Ligament Injuries (MRI)
Age
Age patterns for medial collateral ligament (MCL) and lateral collateral ligament (LCL) injuries are bimodal, with the highest incidence rates found in individuals aged 20-34 years and in persons aged 55-65 years. Nonetheless, MCL and LCL injuries can occur at any age.
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The medial and lateral collateral ligaments of the knee. Courtesy of Randale Sechrest, MD, CEO, Medical Multimedia Group.
