How are the collateral ligaments structured and how do they tear?
The internal collateral ligament connects the femur to the tibia along the inner surface of the knee and is fused to the joint capsule and the internal meniscus. The external ligament runs from the femur to the head of the fibula and lies separate from the capsule. The internal ligament is damaged when the tibia deviates outward, the external ligament is damaged when it deviates inward, which happens less frequently, but is more severe due to the proximity of the peroneal nerve and blood vessels. The severity of the injury is divided into three grades: sprain with microtears, partial rupture and complete rupture with joint instability.
- First degree - sprain, pain without instability
- Second degree - partial rupture with moderate instability
- Third degree - complete rupture and severe instability
- The internal ligament suffers much more often than the external one
- Damage to the external ligament is often combined with nerve injury
- Combination with cruciate ligament and meniscus rupture
Symptoms
The pain is located on the lateral surface of the knee, just above the ligament, and intensifies when the tibia is tilted to the side. The swelling is usually mild and localized, unlike injuries within the joint in which the knee quickly fills with fluid. With a complete rupture, there is a feeling that the knee is diverging, the leg gives out on uneven surfaces and when turning. Bruising may take a few days to appear. If at the time of injury there was a loud bang and the knee immediately swollen, the cruciate ligament was probably also damaged.
- Pain on the inner or outer surface of the knee
- Local swelling over the ligament
- Pain when bending the leg to the side
- Feeling of joint divergence when supporting
- Bruising after 1–3 days
- Lameness and gentle gait
Diagnostics
The doctor checks the stability of the knee by tilting the tibia in and out with the leg straight and flexed at about 30 degrees: the amount of joint space opening and the presence or absence of a clear end point can determine the extent of the damage. X-rays are needed to rule out a fracture or avulsion of a bone fragment; in adolescents, to rule out damage to the growth plate, which gives a similar picture. An ultrasound clearly shows the ligament and the site of the rupture. MRI remains the main method for suspected combined injuries of the menisci and cruciate ligaments.
- Lateral load tests in extension and flexion
- X-ray of the knee to rule out a fracture
- X-ray with stress for unclear degree of damage
- Ultrasound of the lateral ligaments
- MRI of the knee joint for suspected concomitant injury
- Assessment of peroneal nerve function in external ligament injury
Treatment
In the first days, rest, cold through the fabric, elevated position and elastic compression are used, and the load is limited. Isolated injuries of the internal ligament of the first and second degrees are treated without surgery: using an orthosis with lateral hinges, allowing walking with a gradual increase in support, and starting exercises early. In case of complete rupture of the internal ligament, they are often treated with an orthosis for 6 weeks. Surgical treatment is discussed for complete rupture of the external ligament and posterolateral structures, for separation of the ligament with a bone fragment, and in combination with rupture of the cruciate ligaments.
- Rest, cold and compression in the first days
- Articulated orthosis with lateral support
- Metered support with gradual increase in load
- Early range of motion and hip strength exercises
- Surgery for rupture of external structures and associated injuries
- Pain relief as prescribed by a doctor
Recovery and return to sport
The time frame depends on the degree: for a sprain, return to activity takes about two to three weeks, for a partial tear - four to six weeks, for a complete tear - two to three months or longer. The program is built sequentially: first, removing swelling and restoring extension, then strengthening the quadriceps and hamstring muscles, then balance exercises, running in a straight line, and only at the end, turns and jumps. Return to sports is possible when there is no pain or swelling, strength is close to the healthy leg and the knee is confidently controlled. For prevention, warming up and strengthening the pelvic muscles are important.
- Restoring full extension first
- Strengthening the hip and pelvic muscles
- Balance and knee control exercises
- Step-by-step addition of running, turning and jumping
- Return to sports according to functional criteria, not according to the calendar
- Warm-up and prevention programs to reduce the risk of recurrence