What are these tears?
The quadriceps muscles on the front of your thigh straighten the knee. They pull through the quadriceps tendon, over the kneecap, and then through the patellar tendon to the shin bone. Together this chain is called the extensor mechanism. If either tendon tears completely, you lose the ability to straighten the knee against gravity.
Quadriceps tendon tears are more common after age 40, and patellar tendon tears tend to affect younger people. Both usually happen with a sudden forceful contraction of the quadriceps, as in landing awkwardly from a jump or catching yourself when you slip. Tendons weakened by tendinopathy, chronic illness, steroid use, fluoroquinolone antibiotics or a prior knee replacement are more prone.
What does it feel like?
Many people feel a pop with immediate pain, swelling and bruising, then find they cannot straighten the knee or lift the leg while lying down. The knee may give way when you try to stand. A gap or dent above or below the kneecap can sometimes be felt. Complete tears are an urgent problem. See an orthopedic surgeon within days.
Do I need surgery?
For complete tears, yes, in nearly all cases. Without a repair the extensor mechanism does not heal, and the knee cannot straighten under load. Delay allows the tendon to retract and scar, which can mean a larger operation with grafting. Partial tears in which you can still straighten the leg may do well with bracing and rehabilitation.
What happens in surgery?
Dr. Stepanyan reattaches the torn tendon to the kneecap using strong sutures through bone tunnels or suture anchors. Careful tensioning matters so that the kneecap sits at the right height. In long-standing tears, or when the tendon is of poor quality, a graft or reinforcement may be used. Surgery is often done as an outpatient.
Should I get a second opinion?
If an injury was labeled a sprain but you still cannot lift your leg straight, it is worth another look quickly. Request a visit and mention the injury date.
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 extensor tendon repair. Your own plan may differ.
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Weeks 0–6
Protect the repair
The knee is protected in a hinged brace, usually locked straight when you walk, with crutches as needed. Motion is limited and increased week by week.
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Weeks 6–12
Restore motion
The brace is unlocked and weaned. You work toward bending the knee fully and walking without crutches.
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Months 3–6
Build strength
Quadriceps strengthening picks up. Cycling and swimming are introduced.
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Months 6–9
Return to activity
Running and sport resume gradually once strength has returned and Dr. Stepanyan clears you.
The quadriceps often takes many months to regain full strength. Following the progression is key to protecting the repair.