‘Dislocation’ of the patella (knee cap) often involves a traumatic incident where there is a powerful force to the kneecap, or a powerful quadriceps contraction.
This causes the kneecap to move out of its usually position within the groove of the knee, usually moving to the outer side.
‘Patellar instability’ can occur after a dislocation, or if a client has risk factors that make them more susceptible (such as hypermobility, a high rising patella called ‘patella alta’, a shallow trochlear or groove). Patellar instability means the kneecap is less stable and more susceptible to dislocate.
- If an acute injury – can see the kneecap displaced to the side. Rapid swelling, bruising and pain can follow.
- Tenderness around the kneecap.
- Apprehensive to move knee – feelings of instability, or like the kneecap is going to pop out of place.
- Muscle imbalance – tight outer leg muscles, weaker inner leg muscles (especially a quadriceps muscle called VMO).
- In the case of a dislocation, spontaneous reduction of the patella is common (where is goes back into place by itself).
- A physiotherapist will often recommend R.I.C.E (rest, ice, compression, elevation) immediately post injury.
- Rehabilitation is recommended to regain full knee range of motion and strengthen weaker muscles (particularly VMO and hip control).