The knee joint is comprised of the femur (thigh bone), tibia (shin bone), fibula (lower leg bone on the outside), patella (knee cap), meniscus (cartilage within the knee), and the surrounding muscles and ligaments. The four major ligaments of the knee are the medical (MCL) & lateral collateral (LCL) and the anterior (ACL) & posterior cruciate ligaments (PCL). The surface of the bones inside the knee joint is covered by articular cartilage, which absorbs shock and provides a smooth, gliding surface for joint movement.
Any one of these can be the source of knee pain, but two very common types of non-traumatic knee problems are patellofemoral pain syndrome (PFPS) and iliotibial band syndrome (ITBS). Acute knee sprains involve ligamentous and / or meniscus tears, although meniscus tears can be non-traumatic degenerative tears.
Acute injuries to the knee can cause considerable disability and time off sport. Commonly, it occurs in sports, either contact or non-contact that require twisting movements and sudden changes of direction, especially sports such as football, basketball, netball and hockey. Injuries range from mild with minimal damage to severe where ligaments can be ruptured, meniscus torn or bones fractured. Pain, bruising, or swelling may be present and can develop within minutes of the injury.
Knee Sprains- ACL, PCL, MCL & LCL
A knee sprain occurs when a ligament within the knee is stretched or torn. Symptoms vary depending upon the grade (I, II, or III) of the sprain and the specific ligament that is injured – ACL, PCL, MCL or LCL. The morbidity and management will vary depending on which of these ligaments is injured. Common symptoms of knee sprains include:
∙ Pain and swelling – Both will vary depending on the grade of sprain. Pain may be dull for mild sprains and sharper with more severe sprains.
∙ Limited mobility
∙ Popping noise – You may hear an audible popping or snapping sound at the time of injury. It may indicate that one or more ligaments were torn, suggesting a more serious (Grade III) sprain.
∙ Inability to weight bear
∙ Buckling of the knee – Weight bearing may result in giving way of the knee due to ligamentous laxity e.g., an ACL injury may cause the knee to buckle forwards.
∙ Bruising – May indicate a more serious sprain (Grade II-III)
Below is a classification of the grade and the severity of ligament injury.
Grade I: Usually minor with minimal impact on most activities and usually recovers in 1-3 weeks.
Grade II: Moderate to significant impact on activities associated with pain and usually recovers in 3-6 weeks
Grade III: Complete tear associated with significant morbidity. May take 6-12 weeks to recover.
MCL, LCL and PCL tears (Grade I-III) are mostly conservatively managed and make a full functional recovery.
A grade III ACL tear will require surgery and up to six months of rehabilitation post- surgery.
Meniscus tears are common in contact sports like football as well as non-contact sports requiring jumping and cutting such as soccer. They can happen with sudden changes of direction and often at the same time as other knee injuries, e.g., an ACL injury. Older athletes are more at risk because the meniscus weakens with age, whereby 40% of people 65 years or older suffer from meniscus damage. There are two different types of meniscal tears:
These are commonly due to trauma or sports involving twisting motions. Acute tears have different shapes (horizontal, vertical, radial, oblique and complex). Surgery is sometimes indicated.
These result from chronic asymmetrical loading in the knee joint causing the meniscus to be worn. Surgery is sometimes indicated if conservative management is ineffective.
Patellofemoral Pain Syndrome
PFPS also known as ‘runner’s knee’, is discomfort often associated with crepitus (crackling sounds) at the front of the knee arising from the mal-tracking of the patella in its femoral groove (area where the knee cap moves). Poor biomechanics in the patella femoral joint (PFJ) wears down the cartilage that lines both these structures thereby causing pain.
PFPS Signs and Symptoms:
∙ Common in both athletes and non-athletes, but more so in teenagers, and women more than men.
∙ Non-traumatic onset, often gradual, but can arise from a single event
∙ Pain with knee flexion (bending) positions / activities e.g., sitting, steps, cycling, running
∙ Factors that contribute to higher incidence of PFPS can be the shape and size of the patella and muscle imbalance in the leg placing asymmetrical loads on the PFJ
Up to 25% of the population will suffer knee pain and of these, 50% will be PFPS. Either PFPS or ITBS (see below) can cause mild discomfort to severe pain and effective treatment aimed at the cause of the dysfunction is extremely successful at returning you to your sport.
Iliotibial Band Syndrome
ITBS occurs when there is pain on the lateral aspect (outside area) of the knee. It is a non-traumatic overuse injury common in athletes caused by the iliotibial band (tendon like structure) rubbing against the lateral epicondyle of the knee (bony prominence) resulting in inflammation, swelling and pain of the iliotibial band.
∙ ITBS occurs in 5-15% of runners
∙ Most frequent in athletes performing repetitive knee flexion / extension motions e.g., cyclists and runners
∙ Pain may not occur immediately during activity, but may intensify over time.
PFPS and ITBS are often multifactorial in cause, but definite features are asymmetrical and / or excessive loading on the PFJ or ITB due to poor biomechanics in any region of the musculoskeletal system. Non-optimal movement strategies anywhere in the body can cause compensatory movement patterns in the lower limbs placing excessive and usually repetitive strain on these areas. Other factors that contribute to PFPS and ITBS are:
∙ Excessive loading from increased training intensity or inappropriate exercise regimes especially with repeated knee flexion/extension motions
∙ Poor biomechanics of the foot, ankle, knee, hip or pelvic girdle
∙ Insufficient core trunk and global muscle strength leading to overuse and an imbalance of lower limb muscles especially weak hip abductors (gluteal muscles).
Physiotherapy management of PFPS and ITBS is highly successful at PhysioMotion. In addition to our treatment principles for joint pain treatment will involve manual ‘hands on’ joint corrections, soft tissue release, acupuncture and dry needling techniques, and an individualized exercise program including abdominal / trunk core stability with real time ultrasound imaging and stability retraining.
For knee sprains and meniscus tears, our Physiotherapists will perform a comprehensive assessment to diagnose the severity of the injury and start a progressive treatment protocol to expedite recovery using our treatment principles for joint pain. Early intervention is highly recommended to prevent further damage and unwanted compensatory mechanisms in other regions of the body.
Once a definitive diagnosis has been made, initial treatment will be aimed at reducing pain, swelling and subsequent morbidity. For optimal healing and prevention of further injury, the most progressive post-surgical protocols will be used during your rehabilitation. In non- surgical cases, a whole body individualized biomechanical assessment will be performed to ascertain why you were predisposed to such a knee injury.