Lateral collateral ligament (LCL) partial rupture

Lateral or fibular collateral ligament (ligamentum collaterale lateralis, LCL) is situated along the lateral knee region, from the distal part of the femur where it originates from (epicondylus femoris lateralis) to the proximal part of the lower leg (caput fibulae). The main purpose of the LCL is preventing lateral shifting or slidding of the knee, ie. the varus knee stress and together with the anterior cruciate lig., medial collateral lig. and posterior cruciate ligament it forms a group of the most important knee joint passive stabilizers.

LCL injuries are less frequent due to the fact that it is more mobile, ie. flexible than the MCL. The MCL is connected to the medial meniscus and medial parts of the knee joint capsule, but the LCL is not connected to neither the lateral meniscus or the lateral parts of the joint capsule which gives him more mobility and decreases the risk of its injury. The common LCL injury mechanism is varus collapse/stress of the knee joint caused by a force impacting the medial part of the knee and pushing it outwardly, ie. during a blow to the knee. Varus knee stress can also occur during knee hyperextension and the LCL can also get injured and damaged. Injuries of this ligament are frequent in sports activities where direct blows/hits to the knee can occur, eg. football, soccer, skiing, karate, tae-kwon-do, etc. They are also known to happen in car crashes and it should be stated that LCL injuries are often combined with injuries to other knee ligaments or joint capsule soft tissue structures.

Symptoms encompass pain in the lateral aspect of the knee, instability and knee buckling during walking, knee swelling and hematoma at the place of the injury. Sometimes, direct trauma, can cause peroneal nerve (nervus peroneus) damage which can lead to the foot falling down during walk, loss of feeling  or tingling in the lateral part of the lower leg and foot.

Grades of LCL injuries:

1. LCL sprain: ligament gets excesively stretched, but its tissue does not get disconnected; rehabilitation lasts up to 1 month

2. Partial LCL rupture: ligament tissue gets partially disconnected, the knee can be instable and rehabilitation lasts  from2-3 months

3. Complete LCL rupture: the most severe LCL injury, the knee is instable, the ligament tissue completely disconnected across its width, often combined with other injuries of the knee joint; rehabilitation lasts up to 4 months and in some cases requires surgery

Rehabilitation and choice of therapy approach depend on the gravity of injury, if only an LCL sprain has occured a conservative apporach is used and with complete LCL ruptures which are combined with other parts of the knee being injured a surgical approach is implemented and the LCL gets reconstructed. LCL reconstruction is done with either an autograft (transplant comes from the patients own tendon tissue) or an allograft (transplant from a cadaver). In acute phase of therapy RICE method (rest, ice compression, elevation) is used to reduce pain, swelling and hematoma. Functional phase is aimed at progressive regaining of knee joint range of motion, upper leg strenght (quadriceps, hamstrings, gluteal muscles) and knee joint stability.