Patella or Kneecap Dislocation

Your kneecap may dislocate or feel unstable following an injury, or you may describe the feeling of your kneecap dislocating repeatedly.

When being examined your patella will feel unstable as if it might dislocate again. This sign is call apprehension.

Why does my knee cap pop out (dislocate)?

Risk factors for patella dislocation:

  • high-riding kneecap (patella alta)
  • a very shallow trochlea groove
  • skeletal immaturity

In the past, the time-honoured approach has been to avoid surgery and to work on a good rehabilitation program after the first dislocation episode. If the patella then dislocates or partly dislocates two or three more times, preventing a safe return to sport, only then is surgery advised.

Treatment of Patella Dislocation

Every individual needs a thorough assessment, and discussion with their family and specialist knee surgeon, to decide the best plan between rehabilitation alone, or surgery plus rehabilitation.

​In the majority of index first-time dislocations, once the initial swelling subsides it is very important to commence a good rehabilitation program with a specialist physiotherapist.

​If the patella remains unstable after the first dislocation despite physiotherapy, it may be time to consider surgery before recurring episodes result in permanent damage to the joint surface.

​It is now recognised that the key element for successful treatment of an unstable patella is to reconstruct the check-rein on the inner side of the patella called the medial patellofemoral ligament (or MPFL for short).

​In addition, if there is malalignment of the patella and/or if the patella sits too high, it is considered optimal to correct those contributing factors as well with a tibial tubercle transfer.

Such surgery requires a minimum of three months of recovery and rehabilitation, and as a result it is important not to rush into the operation.

Surrey Orthopaedic Clinic Knee Specialists: