see also:

• dislocation of the knee joint
• the acutely injured knee in ED

• dislocated patella is a very common ED presentation in the adolescent and young adult in particular.
• classically they present by ambulance with it still dislocated and holding a Penthrane analgiser stick.

• diagnosis is clinical and is usually very obvious that the patella is dislocated
• most patients can be rapidly managed by simple closed reduction even whilst on ambulance trolley while they breathe on the Penthrane
• reduction is achieved by pushing medially on the lateral aspect of the patella with your thumbs while an assistant extends the knee

• Xray with patella sky-line views should be done to exclude osteochondral avulsion fragments which can be large and may require operative Mx if present.
• patients with no significant fracture are usually discharged home with Zimmer splint, crutches and analgesics and advised to have physiotherapy follow up to reduce the risk of subsequent dislocations.