The anatomy of the Knee

Sports Injuries

> Anterior Cruciate Ligament Injuries

An ACL sprain or tear is a very common knee injury. Quite often associated with high demand running and change of direction sports, the injury has been described as the classic plant pivot pop type of injury where the pop is the sensation as the knee gives way. The ACL injury may be catagorised as a grade 1, 2 or 3 injury, where grade 3 is complete rupture. Complete rupture presents with pain, swelling, instability and loss of range of motion. Surgical reconstruction is advised in most cases.

> Posterior Cruciate Ligament Injuries

The PCL is located at the back of the knee and stops the tibia moving backwards. It is less common to injure the PCL than other types of knee ligaments. Impact injuries like dash boards of cars hitting the knee or hyper-extension injuries are the typical mechanisms of injury. The PCL injury may be catagorised as a grade 1, 2 or 3 injury, where grade 3 is a complete rupture. Complete rupture presents with pain, swelling, instability and loss of range of motion. Surgical treatment may be advised if the patient wishes to return to a high level of function.

> Collateral Ligament injuries

Collateral ligaments of the knee are the ligaments which brace the sides of the knee joint. There is the Medial Collateral Ligament (MCL) and the Lateral Collateral Ligament (LCL). As with other types of ligament tears, collateral ligament injuries are catagorised as a grade 1, 2 or 3 injury, where grade 1 is slightly stretched and grade 3 is a complete tear or rupture. The MCL is more frequently damaged than the LCL due it being easier to create a valgus strain versus a varus strain. Pain, swelling and instability are the symptoms and typically immobilisaton without surgery is the recommended treatment.

> Combined knee Ligament injuries

Combined knee ligament injuries are complex injuries and an assessment of which ligaments have been affected and the recovery expectation of the patient need to be carefully considered. Multi ligament tears present with pain, swelling and inflammation. Treatment is often surgical and had best soon after the injury. Arthrofibrosis or scar tissue of the joint is a risk factor to consider for surgery of these conditions.

> Discoid Meniscus

A discoid meniscus is an abnormally shaped meniscus in the knee. People with discoid meniscus are more prone to injury than those with a normal meniscus. Squatting and twisting motions are the typical mechanisms of injury. Symptoms are more frequent in the young. There are 3 types of discoid meniscus, incomplete, complete and hypermobile wrisberg. Meniscal injuries present with pain, stiffness, swelling, catching, locking, and altered range of motion. MRI scans can verify meniscal pathology which is best treated surgically.

> Meniscal Tears

Meniscal tears are of the most common types of knee injuries. Meniscus is commonly described as cartilage and is the shock absorber of the knee sitting on the tibia and below the femur. It is relatively easily torn by heavy squatting and twisting movements. There is a medial meniscus and a lateral meniscus making up menisci of the knee. Tears are described as longitudinal tears, parrot beak, bucket handle, transverse, radial, flap, and mixed or comlpex tears. Meniscal injuries present with pain, stiffness, swelling, catching, locking, and altered range of motion. MRI scans can verify meniscal pathology which is best treated by surgical repair.

> Osgood - Schlatter Disease

Osgood-Schlatter disease is an overuse injury of the knee in adolescents resulting in pain, swelling and tenderness below the kneecap. Treatment involves managing the pain and inflammation usually by a course of non steroidal anti inflammatory drugs (NSAIDs). In some patients, Osgood-Schlatter's may last 2-3 years, but in most cases passes at the end of the growth spurt at 14-16 years old.

> Patellar Tendon Tear

The patellar tendon is the tendon below the kneecap joining the patellar to the tibia. It is a very strong tendon and resistant to injury. The mechanism of injury of a patellar tendon tear includes direct impact, a weakening of the tendon via overuse tendinitis or chronic disease caused by disrupted blood flow to the tendon. XRay and MRI scans will confirm rupture of the patellar tendon, which is best treated by surgical repair.

> Patellar Dislocation and Instability in Children

A child's kneecap should sit in the middle of the knee in a groove of the femur called the trochlear groove. During knee movement, the kneecap should move up and down within the groove. When the patella slips out of the groove, it is known as a partial or complete dislocation of the kneecap. This is a very painful experience associated with loss of movement, even if the kneecap returns to the groove after it has slipped out. If the kneecap remains dislocated the child should be taken to emergency to have it reduced. Pain and inflammation should be managed with physiotherapy including immobilisation and VMO quads strengthening. Surgical treatment is only necessary if the patient experiences multiple dislocations.

> Runner's Knee (Patellofemoral Pain)

Runner's knee is a term used to describe a number of medical conditions which cause pain around the front or anterior part of the knee. Often, malalignment of the patella caused by a number of different factors contribute to the condition. Adequate stretching and strengthening of the muscles of the knee are measures to prevent and treat runner's knee. Surgical treatment is available for severe cases where patella maltracking is frequent.

> Unstable Kneecap

When the knee is functioning properly, the kneecap runs smoothly in a grove of the femur called the trochlear groove. If the kneecap slides out of this groove, the kneecap will become unstable. Anatomy anomalies like shallow or uneven grooves may cause the kneecap to slide out, or an injury such as a heavy fall or sharp blow to the kneecap may cause it to dislocate. Bracing and strengthening exercises treat minor and single episode dislocations while surgery is advised to correct multiple dislocation injuries.

> Quadriceps Tendon Tear

The quads tendon sits above the knee, joining the quads muscles to the top of the patella. Tears are more common in middle aged populations. The mechanism of injury is an eccentric (lengthening) contraction of the quads resulting in a painful disabling condition. Tendon weakness caused by tendinitis or chronic disease will result in higher risk of sustaining a quads tendon tear. All quads tendon tears should be treated surgically.

> Shin Splints

The term "shin splints", refers to pain along the inner edge of the shin bone. Shin splints are an over use injury, involving inflammation of the muscles, tendons and bone of the tibia. Shin splints occur with a sudden change of frequency and load of exercise. Those with poor arch support or flat feet are at higher risk of developing shin splints. Shin splints may develop into stress fracture, tendinitis or chronic exertional compartment syndrome. Treatment involves rest from erxercise, inflammation management and arch supports for feet. Surgical treatment is not indicated.


> Distal Femur (Thighbone) Fractures of the Knee

Fractures of the top part of the knee are called distal femur fractures. They typically occur in the elderly or in high impact injuries such as a car crash. Distal femur fractures can be described as transverse (straight across), comminuted (many pieces) or intra-articular (extend into the knee joint). Additionally these types of fractures may be open (where the skin is broken), or closed (where the skin is intact). Due to the strong musculature around these fractures, it is common for the muscles to shorten and move the boney fragments away from correct alignment. Surgery is often indicated for distal femur fractures.

> Proximal Tibia (Below Knee) Fractures

Fractures of the bottom part of the knee joint are called proximal tibia fractures. While most of these fractures occur as a result of trauma, they can also occur as a result of stress fracture or compromised bone due to infection, cancer or osteoporosis. Fractures of this region are described as transverse, comminuted or intra articular. Intra articular fractures involve fracture of the tibial plateau, a much softer part of the tibia which sometimes presents as a depression in the bone rather than a fracture. Surgical correction and immobilisation are recommended in proximal tibial fractures.


> Arthritis of the Knee

Arthritis is inflammation of one or more joints. Arthritis is a disease and it is particularly common in the knee. There are many forms of arthritis, however, osteoarthritis is the most common. Osteoarthritis is a degenerative "wear and tear", type of arthritis which sees articular cartilage thinning and being replaced by boney spurs. Over time, the arthritic knee joint space diminishes and load bearing activity causes severe pain. There is no cure for arthritis and when conservative treatment no longer helps with pain management, total joint replacement surgery becomes necessary.

> Unicompartmental Knee Replacement

For sufferers of osteoarthritis in the knee who's problem is limited to only one side of the knee, a uni compartmental knee replacement is an alternative surgical option to total knee replacement surgery. Your orthopaedic surgeon should be consulted to discuss the extent of your arthritis to determine if a uni compartmental knee replacement is right for you.

> Total Knee Replacement

Advanced arthritis of the knee is very painful. When non surgical treatments like medications and gentle exercise no longer manage pain, the total knee replacement surgery is an effective way to relieve pain, correct deformity and improve function of the knee. Total knee replacement surgery is also called knee arthroplasty. Knee arthroplasty involves implanting new femoral, tibial, tibial insert and patella components into the knee joint. The implants may be cemented or press fit into position. The goal of surgery is to balance the knee so that future wear and tear of the new joint occurs as evenly over the new implant surface as possible. Physiotherapy is a very important part of the post op recovery process of total knee replacement surgery.

> Biomet Personalized (PSI) Total Knee Replacement

Whilst your choice of a long lasting total knee replacement prosthesis is important, equally it is important to get the positioning and balance right when putting it in. A combination of using the Biomet Vanguard total knee replacement prosthesis and the Signature personalized (PSI) technology, means you get a powerful combination of durability and fit for the maximum possible life of your joint replacement.

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