The knee has strong ligaments on both the inside of the knee (medial collateral ligament) and the outside of the knee (lateral collateral ligament). These ligaments attach to both the thighbone (femur) and to the shinbone (tibia). These two collateral ligaments provide stability to the knee, especially in resisting medial and lateral forces. If there is sufficient force, however, either of these collateral ligaments may become injured.
Common Causes
Struck in the side of the knee or leg during a football tackle. Rapid pivoting, in soccer or basketball.
Symptoms
Pain in the knee, either in the inside (most common) or outside of the knee. There may be feelings of instability in the knee with weight bearing or walking. There may be swelling or bruising present.
Physical Findings
Tenderness along the injured collateral ligament. Pain with stress testing of the ligament.
Workup
In addition to history and physical examination, x-rays are usually obtained to make sure there is no fracture. MR scans are usually not necessary in an isolated collateral ligament injury.
Non-operative Treatment
Functional knee bracing until the ligament is healed. This may take months in some cases.
Surgical Treatment
Ligament repair.
Injury Comment
Surgery is almost never required collateral ligament injuries of the knee, and non-operative treatment usually gives good results.