What to do ? – Acute Patellar Dislocation

What to do ? – Acute Patellar Dislocation

October 12, 2021

An acute dislocation of the patellar can be a very traumatic event for a child or adolescent - so here is a guide as what to do

An acute patellar dislocation usually occurs during activity when the flexed knee rotates inward worn due to a direct blow to the knee. The patellar dislocates outward (laterally) and the knee collapses. Weight bearing is not possible and the knee looks strangely swollen.

The patellar with reduce (go back in place) if the knee can be gently straightened but if it is too painful a visit to the hospital is required so pain relief can be given

Once back in place the knee should be gently examined for other injuries, an Xray taken, a compression bandage applied and the leg placed in a Zimmer splint. Crutches are usually required.

All first time dislocations should undergo an MRI examination of the knee within the first 5 days as in 20% of cases cartilage may be knocked of the joint surface and need arthroscopic reattachment or removal.


Oral pain killers should be given, the knee regularly iced and once comfortable referral to a physiotherapist is essential. Nearly 50% of patients that experience a dislocation with develop patellar instability so good rehabilitation is important

For more details see the fact sheet on acute patellar dislocation on the website