A common knee injury amongst the active population is the
damage to or rupture of the anterior cruciate ligament (ACL). The role of this
ligament is to stabilize the knee joint by stopping the bottom of the leg from
collapsing forward under the knee joint, particularly during deceleration, landing,
or turning and cutting actions. It is unusual for the ACL to be injured in
isolation; often other ligaments and/or the meniscus are also injured. Those at
greater risk of tearing the ACL are, therefore, those involved in jumping and
pivoting sports, as well as contact sports, such as soccer and rugby. A muscle
strength imbalance between the hamstrings and the quadriceps muscles (back and
front of the thigh respectively) can also increase the risk of this injury
occurring.
Signs and Symptoms
As the injury occurs, a popping, tearing, or snapping sensation
may be heard or felt, followed by swelling around the knee joint. Pain may be
felt immediately or occur later and may range from mild to severe. The pain may
be felt deep in the knee joint or, more commonly, on the front side of the
knee. Generally, one is able to walk on the affected leg; however, this is
often associated with a feeling of the knee wanting to collapse or a general
feeling of discomfort. Because of the high likelihood of other surrounding
tissues being damaged as well, it is important to consult a specialist for
further investigation.
Management
Depending on the severity of the damage to the ACL and the
involvement of the surrounding structures, an ACL injury is either treated
conservatively or surgically.
Conservative management involves rest, ice, compression,
elevation and immobilization of the knee joint to reduce swelling. Crutches can
be used if walking is too painful. Pain-free range of motion exercises are
performed to maintain mobility in the joint. Gentle and appropriate
strengthening exercise are done to maintain muscle strength. Physiotherapy is
very important in these initial stages of recovery. Upper body exercises can be
continued throughout the recovery period. Strengthening, range of motion and
proprioception and balance exercises can be progressed appropriately by a
biokineticist until the individual is back to full function. This can take
anywhere between 6 weeks to 3 months, depending on the severity of the injury
and the compliance of the individual with the rehabilitation programme.
If there is a complete rupture of the ACL or multiple
surrounding tissues are also affected, surgery is usually recommended so that
an individual can return to contact or pivoting-type sports. Depending on the
other structures damaged, the repair and recovery will be slightly different. A
graft is taken from the hamstring muscle to repair the ACL, which means that
the hamstring muscle also needs to be carefully rehabilitated and strengthened
to avoid a later hamstring injury. After surgery, the affected leg is
immobilized in a full-leg brace, which can be locked at various degrees of
flexion and extension. One will more than likely be non-weight-bearing for
between 2 and 6 weeks, again depending on damage to other structures, such as the
meniscus. Physiotherapy is crucial to maintain range of movement in the joint
and reduce swelling. Again, gentle strengthening exercises are done to maintain
muscular strength around the knee. Once the brace is removed, the
rehabilitation will follow in a similar fashion to the conservative treatment
plan, progressing appropriately with the guidance of a biokineticist, with an
additional focus on the rehabilitation of the affected hamstring muscle. If
properly rehabilitated, one should be able to return to sport if they have not
lost the nerve to do so.
References
Foundations of Athletic Training: Prevention, Assessment and
Management
