Isolated MCL (Medial Collateral Ligament) Injury
Updated: Aug 4, 2019
Mechanism of Injury
Typically occurs with a force to the outside of the knee causing the knee to bend inward. Commonly seen when an athlete is tackled. Additionally, can sustain an MCL injury in a non-contact mechanism when a foot get stuck in the turf or tangled up with another individual. An isolated MCL injury may have a greater impact on an athlete that has a greater need for side to side motions, as well as cutting, pivoting or change of direction.
Athletes will usually have swelling over the inside (medial) aspect of the knee. There will also be tenderness to the touch over the inner aspect of the knee. On examination, if the knee is pushed from the outside towards the inside it can replicate the pain by stretching the MCL. Typically this exam technique is called a valgus stress test. If there is fluid on the entire knee (effusion), one should be concerned for other injuries, such as an ACL tear.
Valgus Stress Test
Diagnosis & Treatment
In general, isolated MCL injuries can be treated without surgery and will improve with time and proper rehabilitation. A mild MCL strain (Grade 1) may only need 1 or 2 weeks recovery, up to about 4 weeks. Grade 2, partial tear, typically will recover in 4 to 6 weeks. A Grade 3, complete tear, can take upwards of 8 to 10 weeks. Rarely, if the knee is very unstable, Grade 3 tears could require surgical intervention. Usually the athlete is placed in a functional hinged knee brace (photo below), which will allow flexion and extension of the knee but limit side to side movement.
Functional Hinged Knee Brace