Sports Medicine
Sports Injury Prevention & Rehabilitation

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Patellar Fracture

Also known as Fractured Patella, Fractured Knee Cap)
What is a patellar fracture?
A patellar fracture is a condition characterized by a break in the knee cap bone, known as the patella.
The knee comprises of the union of three bones – the long bone of the thigh (femur), the shin bone (tibia) and the knee cap (patella). The patella (knee cap) is situated at the front of the knee and lies within the tendon of the quadriceps muscle (the muscle at the front of the thigh). The quadriceps tendon envelops the patella and attaches to the top end of the tibia. Due to this relationship, the knee cap sits in front of the femur forming a joint in which the bones are almost in contact with each other.
During certain activities, such as a fall onto the knee cap or following a direct blow to the front of the knee, stress is placed on the patella bone. When this stress is traumatic, and beyond what the bone can withstand, a break in the patella may occur. This condition is known as a patellar fracture.
Because of the large forces required to break the patella bone, a patellar fracture often occurs in combination with other injuries such as patellofemoral joint damage or a quadriceps tear.
Patellar fractures can vary in location, severity and type including stress fracture, displaced fracture, un-displaced fracture, compound fracture, greenstick, comminuted etc.

Causes of a patellar fracture
A patellar fracture most commonly occurs due to direct trauma to the knee cap such as a fall onto the knee cap or a direct blow to the patella (e.g. from a hockey stick). Occasionally a patellar fracture may also occur due to a forceful quadriceps contraction such as a landing from a height. A stress fracture to the patella although rare, may occur as a result of overuse, often associated with a recent increase or high volume of jumping. An acute patellar dislocation can also sometimes result in a fracture to the patella.

Signs and symptoms of a patellar fracture

Patients with a patellar fracture typically experience a sudden onset of sharp, intense pain at the front of the knee at the time of injury. This often causes the patient to limp so as to protect the patella. In severe cases, particularly involving a displaced fracture of the patella, weight bearing may be impossible. Pain is usually felt on the front or sides of the patella and can occasionally settle quickly with rest leaving patients with an ache at the site of injury that may be particularly prominent at night or first thing in the morning. Occasionally patients may experience symptoms in the back of the knee, the thigh or lower leg regions.
Patients with a patellar fracture may also experience swelling, bruising and pain on firmly touching the affected region of bone. Pain may also increase during certain movements of the knee when standing or walking (particularly up or down hills or on uneven surfaces) or when attempting to stand or walk. Squatting or kneeling is also usually painful with many patients being unable to perform these activities. In severe patellar fractures (with bony displacement), an obvious deformity may be noticeable. Occasionally patients may also experience pins and needles or numbness in the knee, lower leg, foot or ankle.

Diagnosis of a patellar fracture
A thorough subjective and objective examination from a physician is essential to assist with diagnosis of a patellar fracture. X-rays (including a skyline view of the patella) are usually required to confirm diagnosis and assess the severity. Further investigations such as an MRI, CT scan or bone scan may be required, in some cases, to assist with diagnosis and assess the severity of the injury.

Treatment for a patellar fracture

For those patellar fractures that are displaced, treatment typically involves anatomical reduction (i.e. re-alignment of the fracture by careful manipulation under anaesthetic) followed by surgical internal fixation to stabilize the fracture (often using a tension band wiring technique). Surgical repair of the quadriceps muscle may also be indicated in some cases. This may be followed by the use of a protective brace, plaster cast and/or crutches for a number of weeks.
For those fractures that are not displaced, treatment may involve the use of crutches and/or an extension splint or brace, or, plaster cast immobilization and the use of crutches, followed by the use of an extension splint or brace for a number of weeks. The orthopaedic specialist will advise the patient as to which management is most appropriate based on a number of factors, including the location, severity and type of patellar fracture.
  • Evaluation of the fracture with follow up X-rays is important to ensure the fracture is healing in an ideal position. Once healing is confirmed, rehabilitation can progress as guided by the treating physical therapist.
  • One of the most important components of rehabilitation following a patellar fracture is that the patient rests sufficiently from any activity that increases their pain (crutches and / or a protective splint or brace are often required). Activities which place large amounts of stress through the patella should also be avoided, particularly excessive weight bearing activity such as running, jumping, squatting, lunging, kneeling, standing or walking excessively (especially up or down hills or on uneven surfaces). Rest from aggravating activities allows the healing process to take place in the absence of further damage. Once the patient can perform these activities pain free, a gradual return to these activities and weight bearing forces is indicated provided there is no increase in symptoms. This should take place over a period of weeks to months with direction from the treating therapist.
  • Ignoring symptoms or adopting a 'no pain, no gain' attitude is likely to cause further damage and may slow healing or prevent healing of the patellar fracture altogether.
  • Gently icing the patella in the initial phase of injury (first 72 hours) can assist in reducing swelling and pain. This should generally be applied on the way to receiving urgent medical attention and can be maintained for 20 minutes every 2 hours. The use of crutches when walking is usually necessary to protect the patella from further damage and to hasten the healing process.
  • Manual "hands-on" therapy from the therapist such as massage, trigger point releases, joint mobilization, dry needling, stretches, McConnell taping and electrotherapy can also assist with improving range of movement, pain and function following a patellar fracture. This can generally commence once the physical therapist has indicated it is safe to do so.
  • Patients with a fractured patella should perform pain free flexibility, strengthening and balance exercises as part of their rehabilitation to ensure an optimal outcome. This is particularly important, as balance, soft tissue flexibility and strength are quickly lost with inactivity. These rehabilitation exercises will often focus on the function of the quadriceps muscle. Hydrotherapy exercises and the use of a stationary exercise bike may also be indicated during the rehabilitation period. The treating physical therapist can advise which exercises are most appropriate for the patient and when they should be commenced.
  • In the final stages of rehabilitation for a patellar fracture, a gradual return to activity or sport can occur as guided by the treating physiotherapist provided there is no increase in symptoms. This may involve a gradual return to running program to slowly condition the patella to running in a safe and effective manner.
  • It may be advised upon returning to some sports, particularly those involving running or jumping that the patella is either taped or braced for additional support or protection. The treating physical therapist can advise if this is recommended.

Prognosis of a patellar fracture

Patients with a patellar fracture usually make a full recovery with appropriate management (whether surgical or conservative). Return to activity or sport can usually take place in a number of weeks to many months and should be guided by the treating physiotherapist and specialist. In patients with severe injuries such as those that involve damage to other bones, soft tissue, nerves or blood vessels, recovery time may be significantly prolonged and there may be some ongoing disability.
Sometimes a poorly rehabilitated patellar fracture may develop into other conditions such as patellofemoral pain syndrome even though full bony healing may have taken place. In these instances further physical therapy treatment and rehabilitation may be required before the patient is able to return to full activity pain free.

Physical therapy for a patellar fracture

Physical therapy treatment is vital in all patients with a patellar fracture to hasten healing and ensure an optimal outcome. Treatment may comprise:
  • soft tissue massage
  • joint mobilization
  • electrotherapy (e.g. ultrasound)
  • dry needling
  • taping or bracing
  • the use of a protective splint or brace
  • the use of crutches
  • exercises to improve strength, flexibility and balance
  • hydrotherapy
  • education
  • activity modification
  • a graduated return to activity plan
  • footwear advice

Other intervention for a patellar fracture
Despite appropriate physical therapy management, some patients with a patellar fracture do not improve adequately and may require other intervention. The treating physical therapist or doctor can advise on the best course of management when this is the case. This may include further investigations such as X-rays, CT scan, MRI or bone scan, periods of splinting or plaster cast immobilization or referral to appropriate medical authorities who can advise on any intervention that may be appropriate to improve the fractured patella. Occasionally, patients with fractures that are initially managed without surgical intervention may require surgery to stabilize the fracture and a bone graft to aid fracture healing.