The knee is made up of various muscles, ligaments, tendons, menisci, vascular structures, and bones that effect how it will perform during different tasks. Some of these structures can act dynamically on the knee to provide support throughout a range of motion, and some structures can act passively on the knee to provide support at a specific angle, to a specific force or in a specific positon. The ligaments of the knee represent the latter. Ligaments are passive stabilizers that connect two bones or cartilage and hold them together at a joint. One of the most important ligaments to stabilization of the knee is the medial collateral ligament.
The medial collateral ligament is a passive stabilizer on the ‘medial’ or inside aspect of your knee. It protects the knee joint from a blow or force directed from the side of the knee towards the midline, in other words a valgus force. Fun Fact: when your knee is bent to 25 degrees of flexion the MCL provides 78% of the restraining force! These injuries do not always occur because of contact. They may happen due to a blow to the lateral side of the knee, but they can also occur with cutting maneuvers or with a forceful shift in directions of the knee. MCL injuries rarely occur in isolation, due to the complex nature of their functional anatomy, and their relationship/proximity to the medial meniscus and its ligaments, medial leg musculature, posterior oblique ligament, and joint capsule but injuries in isolation are possible. For the rest of this post, we will frame the discussion around isolated MCL injuries.
In addition to the history of the injury, location of pain, and presence of deformity, isolated MCL injuries will often present with localized swelling which will help to make a proper diagnosis. There are three difference classes of MCL tears. To clarify, the word strain and tear can be used interchangeably for Grades 1 and 2. A strain is a tear of a portion of the ligament without a complete tear, but a tear nonetheless.
Treatment of Tears
Grade 1 and Grade 2 are typically treated non-operatively with proper rest, rehab and gradual return to sports. Initially, the patient will be allowed to bear weight as tolerated, and may even use a knee brace to manage pain and protect it from further injury. As treatment progresses, the focus will move from acquiring full range of motion into strengthening, and return to sport activities. Return to sport for grades 1 and 2 MCL strains typically occur between 20 days and 8 weeks depending on the severity of the strain.
Treatment of grade 3, complete tears, tend to be more controversial and depend on various factors such as level of activity (pro compared to joe), and additional injuries (ex. Avulsion fractures, meniscal damage, ACL involvement). There is evidence to support both operative and non-operative treatment. Options must be thoroughly discussed by the health care team (Patient, surgeon, physician, physical therapist, trainer) to determine the right choice for each specific patient.
MCL Injuries in children
MCL injuries in children are rare because, at a younger age, ligamentous structures are typically stronger than the bone. MCL tears tend to occur after the growth plate has closed. Recently with the continued emphasis on an early age there has been an increasing number of ligament tears that are occurring alongside the bony injuries. Treatment of these bony/ligament injuries in children includes some type of fixation to reduce the bone malalignment and repair of the MCL.
MCL injuries are commonly encountered in sports medicine and the world of athletics. There are variety of treatment options that can be implemented depending on severity and level of play with return to sport. All injuries should be evaluated independently to allow for proper treatment.