Injuries to the knee are common in sport but knee pain may also develop during leisure activities or manual work. Acute knee injuries in sport can be traumatic injuries sustained during contact or non-contact injuries sustained during change of direction at speed. There are also many overuse injuries affecting the knee secondary to increased loading during repetitive and prolonged activity. Knee pain may be caused by imbalances up or down the kinetic chain and the problem might actually be in the hip or ankle. It is important to get an accurate diagnosis as the treatment varies depending on the cause of the problem. Most knee pain won’t go away with just rest and if not managed properly, it usually returns as soon as you go back to the activity that caused it originally.
The knee joint has three compartments. The joint between the femur (thigh bone) and tibia (shin bone) makes up two of these compartments (medial and lateral) and the patellofemoral joint (between the femur and the knee cap) makes up the third compartment. The three compartments are linked so anything injected into one will spread across all three.
The tibiofemoral part of the knee joint contains two ligaments inside the joint, the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). These ligaments are responsible for stopping the two bones sliding forward or back on each other and also give the joint its rotatory stability. The joint also contains the medial and lateral menisci, two crescent shaped fibrocartilage cushions that sit on top of the tibia inside the knee. The menisci help to dissipate the loading forces on the knee joint as well as helping stabilise and lubricate the joint. There are two additional ligaments outside the knee joint (one on each side). The medial and lateral collateral ligaments help stabilise the knee joint from bending sideways (varus and valgus forces).
The patellofemoral part of the knee joint at the front of the knee is a joint between the patella (knee cap) and the femur (thigh bone). The patella is known as a sesamoid bone that sits inside the quadriceps tendon. Its purpose is to increase the mechanical advantage of the quadriceps during knee extension. During this movement, the patella moves up and down in a groove on the femur. Proper tracking in this groove requires a balance of forces acting on the patella and if there is any imbalance, this can lead to patellofemoral joint pain, a common condition in sport and leisure activity.
The ACL is the most commonly injured knee ligament. Most of these injuries (70%) occur from non-contact injuries. Females and younger athletes have a higher risk of injury but the biggest risk factor for ACL injury is having had one previously. There is usually pain and swelling in the joint. Some people feel the sensation of something popping out during the injury or they might hear a pop at the time.
The diagnosis is made with a combination of clinical examination and imaging tests. The biggest problem after an ACL injury is instability in the knee. The ACL rarely heals after complete tear but not everyone who has an ACL injury needs surgery. A comprehensive rehabilitation program is needed regardless of whether a surgical ACL reconstruction is performed. More information on ACL injuries can be found in the football (soccer) injuries section on ACL tears or in the young athlete section on ACL injury in the young athlete.
Meniscal injuries are common. Medial meniscus tears are more common than lateral, except when associated with an ACL tear, when a lateral meniscus injury is more common. The prevalence of meniscal tears increases with increasing age and they are closely associated with osteoarthritis in older age groups. Only a small part of the periphery of the meniscus has nerve and blood supply so most of the meniscus won’t heal after injury. Degenerative tears are common and can be asymptomatic but acute tears can occur during change of direction with compressive and rotational forces on a flexed knee.
Meniscal tears are diagnosed with a combination of clinical examination and imaging (MRI). It is important to treat the person and not the imaging because it’s common in research to find a meniscal tear in an MRI of a person without any knee pain so a meniscal tear found on MRI might not always be the cause of someone’s knee pain.
The most important part of management of a meniscal injury is a comprehensive rehabilitation program particularly focused on increasing quadriceps strength and addressing any precipitating causes. Surgical management is only indicated for people with mechanical symptoms such as the knee locking or giving way, which happens with specific types of tears. The most common procedure performed is partial meniscectomy (removal of the torn part) because only a small portion of the peripheral meniscus can be repaired successfully and often this is only in younger people. It is best to try to avoid meniscectomy if possible because without part of the meniscus, there is an increased risk of osteoarthritis of the knee.
MCL injuries are one of the most common knee ligament injuries. They can occur on their own but are also commonly associated with an ACL injury. The MCL is often injured during contact or collision sports when the athlete is struck on the outside of the knee, or with sudden change of direction at speed when the shoe gets fixed on the surface but the body rotates. The athlete usually has immediate pain and tenderness but swelling is less obvious than with ACL injury.
Diagnosis is made with a combination of clinical examination and imaging. Most MCL injuries are treated non-surgically and there is a good rate of full recovery and return to sport after a comprehensive rehabilitation program. A hinged knee brace may be needed initially for higher-grade injuries to help with instability in the early phases of the injury. Return to sport is usually between 3-8 weeks depending on the grade of injury. There is a small subset of injuries to the lower part of the MCL that don’t heal well due to the anatomy in the area and these may need surgical repair.
The patellofemoral joint is subject to both acute injuries and chronic overload. A common acute injury is a dislocated patella and less often, the patella can be fractured. Patella tendinopathy is termed jumper’s knee because it affects people in jumping sports such as volleyball and athletics. The patellofemoral joint can have pain due to a specific type of osteoarthritis affecting the patellofemoral joint, sometimes called chondromalacia patella.
The most common cause of anterior knee pain is patellofemoral pain (PFP). This may present in people with structural changes to their knee or the knee anatomy may be completely normal and it may be solely a functional problem. There are many contributing intrinsic factors for PFP including those that are local to the knee such as the shape and position of the patella as well as remote problems from the hip or ankle. These intrinsic factors may be anatomical, due to specific structural features but may also be due to muscle length and strength imbalances and inadequate neuromuscular control. There are also factors extrinsic to the person such as training loads, footwear and training surfaces that can contribute to the problem.
Patellofemoral pain is often worse when running or jumping, when going up or down stairs and after prolonged sitting. Often the pain comes on gradually and there is no specific injury that can be recalled. The goals of treatment are to reduce pain, improve patella tracking and improve function. A comprehensive rehabilitation program is needed to address both local and remote contributing factors and improve both strength and neuromuscular control around the joint.
If you have sustained a knee injury that has resulted in significant pain, swelling or a limp, or you can no longer participate in your preferred activity due to knee pain, a consultation at Shire Sports Medicine can be beneficial for you to get an accurate diagnosis, to help guide management of your condition and to ensure the prevention of further complications.