Knee Fractures

Most knee fractures result from significant, direct trauma to the knee. This may be caused by a fall from a height, a vehicle accident (particularly patella fractures, when the knee hits the dashboard), or a tackle during sports. Less commonly, knee fractures can result from the leg being twisted beyond its usual range of motion.

Some knee fractures are caused by repeated stress, particularly in people who participate in endurance sports or have bone-weakening conditions such as osteoporosis or knee arthritis. People with these medical conditions may experience fractures from low-impact trauma, such as a fall from standing.

Your risks of developing a knee fracture might be increased by:

·      Incorrect sporting techniques – improper movements can cause your knees to move in ways they are not designed for and may increase your risk of falling during your activity. Seek professional guidance to refine your sporting technique.

·      Using ill-fitting shoes – shoes which so not adequately support your feet can alter your gait and subject your knee to different types of stress. They can also cause blisters, bunions, tendonitis, and other injuries which affect the way you walk.

·      Changed exercise environments – switching to a new space may increase your risk of a stress-related knee fracture. Surfaces with slopes, uneven places, or loose elements may increase your risk of falling.

·      Rapid activity increase – suddenly beginning high levels of a new activity places additional stress on your knees, which may contribute to fracture.

·      Poor diet – ensure your diet includes enough calories and nutrients to support your activity levels and bone health.

·      Obesity – excess body weight adds impact on your legs and knees during activities.

Your doctor will begin diagnosing a knee fracture with a physical examination. This involves checking your knee for deformities, feeling it for abnormalities, and asking you to complete certain movements if you can do so. Your doctor will also ask about your medical history, how the injury occurred, and if you are taking any medications. If you have an acute fracture, this will often be done in the hospital emergency room and after an anaesthetic injection into your knee.

Knee fractures can often be diagnosed through a physical exam alone, though your doctor will usually request additional tests to assess its severity and determine ideal treatment These tests may include:

·      X-ray – these are the most common tests used to visualize the knee bones, and are all that’s needed to diagnose a knee fracture in many cases. However, some studies have shown that they may miss up to 2/3 of all stress-related fractures[1], so they may need to be supplemented with other tests.

·      CT scan – these specialized x-rays show cross-sections of your knee, which can help identify how deep the fracture runs or whether the bone has split into smaller fragments. It may be used to plan for surgery.

·      MRI – combining a large magnet and radio waves, these sensitive imaging tests create very detailed images of the knee. As well as detecting a fracture, they may be used to identify other soft structures that have been damaged.

·      Bone scan – this combines x-rays with an injectable radioactive dye called a tracer, and may be recommended particularly if you have a small or stress-related fracture. The tracer collects in the bone and settles in injured areas, making them appear darker and clearer on an x-ray.

·      Blood flow tests – these check the blood supply to your leg below your knee, assessing whether the fracture has impacted it. They can also detect hemarthrosis (blood pooling in the knee joint).

Your treatment options for a knee fracture depend on your overall health, the severity of your fracture, and the level of activity you want to return to after healing. After fully evaluating your knee fracture, your surgeon will take time to discuss all your available options and help you determine which is best for you.

Knee fractures that are small, not displaced, or caused by stress usually do not need surgery. Instead, your surgeon will recommend treating them by using crutches or a walker to reduce weight on your leg, taking pain-relieving medication, and wearing a brace or cast to immobilise your knee as it heals. This is usually followed by physiotherapy to reduce stiffness and strengthen your knee’s muscles.

As your knee includes strong muscles and ligaments which can easily pull fractured surfaces further apart, displaced knee fractures usually require surgery to repair. Some surgeons at Orthopaedics SA have taken additional training to provide arthroscopic knee surgery, letting them perform many corrections through small incisions in your knee.

Other surgical options for repairing your knee fracture may include:

·      Internal fixation – your surgeon can attach metal rods, pins, and plates to the bones in your knee, which hold the bones together as they heal. They are usually not removed after surgery and remain in your body. If you have detached tendons or ligaments alongside your knee fracture, your surgeon may also use internal fixation to help them reattach to the bone.

·      External fixation – if the soft tissue around your knee is too damaged or weak to support an internal fixator, your surgeon may apply external fixators instead. These poke through your skin and attach to a metal frame outside your leg. External fixation is usually temporary, but sometimes needs to remain in place until the fracture is fully healed.

·      Knee replacement – though less common, your orthopaedic surgeon may recommend a knee replacement if you have an existing bone condition (like arthritis) or if the knee bones are unlikely to heal fully. Learn more about knee replacements at Orthopaedics SA.