Patellar Instability
A plain-language overview of patellar instability.
At a glance
- Where
- Knee (kneecap)
- Common signs
- Kneecap slipping, giving way
- Options
- Rehab or MPFL reconstruction
- Urgent?
- Severe pain, deformity, fever, or numbness: seek care promptly.
For general education, not medical advice. Your own surgeon will recommend what fits your situation.
What it is
The kneecap (patella) normally glides in a groove at the end of the thigh bone. In patellar instability it partly or fully slips out of the groove, usually to the outside. The medial patellofemoral ligament (MPFL) is the main soft-tissue restraint that holds it in place.
Common symptoms
- The kneecap shifting or dislocating
- Knee giving way with twisting
- Swelling after an episode
- Pain at the front of the knee
Treatment overview
A first dislocation is often treated with bracing and physical therapy focused on strength and control. For repeated instability, surgery may be considered; MPFL reconstruction uses a tendon graft to rebuild the ligament, sometimes combined with procedures that address bone alignment.