What is patellar instability?
The patella (kneecap) rides in a groove on the end of the thigh bone. It is held in place by the shape of the groove, the muscles that pull on it, and ligaments on both sides. The main stabilizer against outward slipping is the medial patellofemoral ligament (MPFL), which tears in most dislocations.
First dislocations are most common in teenagers and young adults, often during sport and with a twist, but some people are born with a shallow groove, a high-riding kneecap, loose joints or rotational alignment that makes it easy to slip.
What does it feel like?
A dislocation is dramatic. The kneecap shifts to the outside, the knee buckles, and it swells quickly. Most kneecaps pop back into place on their own as the knee straightens. People who have repeated episodes often describe the knee feeling loose, giving way when changing direction, or the kneecap feeling like it is “about to go.” Cartilage on the back of the kneecap or the thigh bone can be damaged during a dislocation.
Do I need surgery after a first dislocation?
Most people who have a first dislocation are treated without surgery, with a short period of protection followed by therapy to restore strength and control.
When is surgery considered?
Dr. Stepanyan is more likely to recommend surgery when:
- The kneecap has dislocated more than once or feels unstable in everyday life
- A first dislocation broke off a piece of cartilage or bone that needs fixing
- There are risk factors that make recurrence likely, such as a shallow groove or a high-riding patella
- Therapy has not controlled the instability
What happens in surgery?
The most common operation is MPFL reconstruction. A new ligament is created from a tendon graft and secured to the kneecap and the thigh bone to hold the kneecap in its track. Loose cartilage pieces are repaired or removed at the same time. When the groove is very shallow or the tendon attaches too far to the outside, additional procedures to reshape the groove or move the tendon may be considered. Dr. Stepanyan will explain which of these are needed for you.
Should I get a second opinion?
If you have had more than one dislocation or have been told surgery is the only option, it can help to hear another view. Request a visit and bring your MRI and X-rays.
Where can I see Dr. Stepanyan?
Dr. Stepanyan sees knee patients in Glendale, East LA and Santa Fe Springs.
What does recovery look like?
These are typical stages after MPFL reconstruction. Your own plan may differ.
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Weeks 0–6
Protect the graft
You use crutches and a hinged brace. Motion is built up gradually and you work on waking up the quadriceps.
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Weeks 6–12
Walk and strengthen
The brace is weaned and you walk without crutches. Therapy builds leg strength and control.
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Months 3–5
Build power
Cycling, swimming and straight-line jogging come back in stages.
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Months 5–8
Return to sport
Cutting and pivoting sports return once strength, balance and control are close to your other leg and Dr. Stepanyan clears you.
Hip and core strength are an important part of keeping the kneecap tracking, so therapy continues even after the knee feels good.