A dislocated knee is a traumatic and severe injury where the bones of the knee joint – the femur (thighbone), tibia (shinbone), and sometimes the patella (kneecap) – are knocked completely out of alignment.
It looks shocking – one of those injuries that makes onlookers wince. The leg may appear twisted or bent in an unnatural direction or at an odd angle. It may swell dramatically, ballooning with fluid and blood due to torn ligaments and other tissues. The skin around the knee may look bruised or red from internal bleeding, and it can feel hot to the touch due to inflammation.
Knee dislocations are often accompanied by damage to the blood vessels, particularly the popliteal artery, which can threaten the limb’s circulation.
A knee dislocation is often a surgical emergency, involving significant damage to the bones, ligaments and neurovascular structures of the knee. Delayed diagnosis risks ongoing knee instability and, in some cases, can even lead to amputation.
What causes dislocation of the knee joint?
A dislocated knee is usually the result of high-energy trauma due to a car accident, motorcycle accident or sports injury.
While they’re usually caused by significant trauma, rising rates of obesity mean we’re now seeing some low-energy knee dislocations caused by the ordinary activities of daily life.
What happens when your knee dislocates?
You may feel intense, sharp pain immediately after the dislocation and your knee may be unable to bear weight (knee instability).
The muscles surrounding your knee may tense up in response to the injury, trying to protect the joint. This makes it difficult to move your leg. In some cases, nerve damage can occur, causing numbness or a tingling sensation in the foot or lower leg.
So, symptoms of a dislocated knee include:
- A deformed knee joint
- A bent knee that you can’t straighten
- Pain, swelling and tenderness
- Knee instability
How common are knee dislocations?
Knee dislocations account for about 0.02% of all orthopaedic injuries, though this is probably an underestimate as about 50% of knee dislocations self-reduce (‘pop back in themselves’) or are misdiagnosed.
Dislocated knees in athletes.
True knee dislocations are a rare injury on the sporting field, being more common in motor vehicle accidents, falls from heights or high energy injury. That being said, these injuries occur not infrequently. Fortunately, with appropriate care and management many athletes return to a good level of function and many are able to get back on the field.
Brody Malone’s dislocated knee
US Olympian Brody Malone famously dislocated his knee after a bad landing at a competition in Germany in 2023. Weeks later, an MRI showed the dislocation was accompanied by a fractured tibia and several torn ligaments.
Malone’s knee required 3 operations and a year of intensive rehab where he had to learn how to walk again.
It paid off though. Malone competed in the Paris Olympics in 2024 with his team earning a bronze medal in the team finals.
Recovery after a knee dislocation
The first step after a knee dislocation is to put the knee back into its rightful position. Sometimes, this happens spontaneously; sometimes it’s done in the emergency room.
There are usually other problems associated with a knee dislocation, including:
- Torn ligaments, muscles or tendons
- Bone fractures
- Neurological injury – most commonly the peroneal nerve
- Arterial injury – popliteal artery.
Depending on the nature of your knee dislocation, treatment options may include:
- Initial immobilisation, pain relief, and swelling management
- MRI and further imaging to accurately define the injury
- Physiotherapy to strengthen the surrounding muscles, improve joint stability and restore range of motion
- Surgery to stabilise the knee and repair soft tissues
- Some severe injuries require emergent treatment, particularly when there is neurovascular injury.
Recovery can be lengthy in severe injury cases. I have a special interest in knee dislocations and severe knee injuries. I prospectively collect data and research on all of my multiligament knee reconstructions through a PROM Program (Patient Reported Outcome Measures) at 3, 6, 12 and 24 months, and at 5 and 10 years to assess their progress. Research is currently demonstrating complex knee injuries may take up to 2 years to reach recovery.
Learn more about patella stabilisation surgery
It may take 3-6 months before you’re able to return to sport.
How can I help?
If you’ve experienced a knee dislocation, I’d love to help. I’m an experienced orthopaedic surgeon with subspecialty training in knee and sports injuries.
I will assess your injury carefully and advise you on surgical and non-surgical approaches. I work closely alongside skilled physiotherapists to ensure you receive appropriate rehabilitation to strengthen and stabilise your knee.
Please make an appointment today.
Disclaimer
All information is general and not intended as a substitute for professional advice.
References
- National Library of Medicine, Anatomy, Bony Pelvis and Lower Limb: Popliteal Artery, ncbi.nlm.nih.gov/books/NBK537125/#, [Accessed 15 October 2024]
- National Library of Medicine, Knee dislocation, https://www.ncbi.nlm.nih.gov/books/NBK470595/#, [Accessed 15 October 2024]
- OrthoBullets, Knee dislocation, https://www.orthobullets.com/trauma/1043/knee-dislocation, [Accessed 15 October 2024]
- Penn Medicine, Kneecap dislocation, https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/kneecap-dislocation, [Accessed 15 October 2024]
- NBC News, After a devastating knee injury, gymnast Brody Malone is back and ready to medal in Paris, https://www.nbcnews.com/sports/olympics/devastating-knee-injury-gymnast-brody-malone-back-ready-medal-paris-rcna160502, [Accessed 15 October 2024]
- University of Connecticut Health, Patella dislocation, https://health.uconn.edu/orthopedics-sports-medicine/conditions-and-treatments/where-does-it-hurt/knee/patellar-dislocation/, [Accessed 15 October 2024]
