Overview
The quadriceps tendon above the kneecap and the patellar tendon below it are the two links that let the thigh muscle straighten the knee. When either ruptures completely, the leg cannot be straightened against gravity and buckles with every step. Repair reattaches the torn tendon to the patella with heavy sutures anchored in bone, restoring the extensor mechanism so the knee can lock, support weight and, in time, run and jump again.
Repaired early, most patients regain full extension and return to their previous activity, including sport, by 5 to 6 months. Dr. O'Donnell performs the repair as an outpatient at Bayside Surgery Center, ideally within the first one to two weeks after injury, before the tendon retracts and scars.
Who It's For
A complete rupture of either tendon, confirmed by the inability to straighten the leg against gravity, is usually repaired surgically in a patient who wants a working leg, because non-operative treatment does not restore active extension. The diagnosis is usually clear on exam: a palpable gap above or below the kneecap, inability to lift the straight leg off the table, and a kneecap that sits too low (quadriceps tendon tear) or too high (patellar tendon tear) on X-ray. Quadriceps ruptures are most common in men over 40 during a stumble or landing; patellar tendon ruptures tend to occur in younger athletes under a jumping load.
Partial tears with the extensor mechanism intact, where the patient can still hold the leg straight, are treated in a brace locked in extension for about 6 weeks with a gradual return of motion. A neglected rupture that is months old may need reconstruction with a graft rather than a simple repair.
A tendon abnormality on MRI is not by itself the reason to operate. Dr. O'Donnell repairs the tendon when the palpable gap, the inability to straighten the leg against gravity, the patellar position on X-ray and the MRI all describe the same complete rupture; a partial tear with intact extension is braced instead. The quadriceps tendon and patellar tendon pages explain the assessment.
What the Procedure Involves
The repair is done under a nerve block plus general anesthesia or a spinal, through an incision over the front of the knee centered on the tear. The tendon ends are cleaned and the pole of the patella is roughened to bleeding bone so the tendon heals directly to it. Heavy braided sutures are woven into the tendon in a locking pattern, then either passed through drill holes bored lengthwise through the patella and tied over the far pole, or fixed with suture anchors set into the patella. Dr. O'Donnell chooses between the two based on bone quality and tear pattern. The retinaculum, the sheet of tissue on either side of the tendon that tears with it, is repaired at the same time because it adds substantially to the strength of the repair. The knee is then flexed to confirm the repair holds to 90° without gapping, which sets the safe range for early rehabilitation. The operation takes about an hour, and the leg goes into a brace locked in full extension.
Risks & How They Are Minimized
The two competing risks are re-rupture and stiffness. Re-rupture is guarded against by a locking suture technique, repair of the retinaculum, and 6 weeks in a locked brace with no active knee extension. Stiffness, particularly loss of flexion, is the more common problem after extensor repairs and is prevented by starting controlled passive flexion early, to about 90° by 6 weeks, rather than immobilizing the knee completely. A persistent extensor lag, an inability to actively straighten the last few degrees, is minimized by quad sets and straight-leg raises from the first days. Infection is uncommon and is addressed with a pre-incision antibiotic and careful handling of the thin skin over the kneecap. Deep-vein thrombosis is a real risk with a braced leg and is prevented with aspirin for 14 days, ankle pumps and early walking. Patella fracture through drill holes is rare and is avoided by placing the holes centrally or, in osteoporotic bone, using anchors.
Recovery & Rehabilitation
The same protocol applies to both tendons. The brace stays locked in full extension for walking and sleeping for 6 weeks, with weight bearing as tolerated in the locked brace; flexion is advanced gradually to about 90° over those weeks, and no active or resisted knee extension is allowed until the repair has healed.
| Phase | Timing | What happens |
|---|---|---|
| Protection | Weeks 0–6 | Brace locked in extension for walking and sleeping; weight bearing as tolerated. Quad sets and straight-leg raises in the brace, patellar mobilizations, passive flexion within the set limit, heel props for full extension. Advance with full passive extension and a straight-leg raise without lag. |
| Motion & early strength | Weeks 6–12 | Flexion progressed to full; brace unlocked for walking and weaned with the crutches. Active knee extension begins, closed-chain strengthening in a limited range, stationary bike, balance work. No deep loaded flexion. Advance with flexion approaching full and a normalizing gait. |
| Strengthening | Weeks 12–16 | Progressive closed-chain strengthening, open-chain extension added as cleared, low-impact conditioning, hip and core work. Advance with full motion, no extensor lag and strength of 70% of the opposite side. |
| Return to activity | Months 4–6 | Progressive strengthening and neuromuscular training, running and agility as cleared, sport-specific drills. Return to sport typically at 5 to 6 months on symmetric strength and functional testing. |
Desk work is possible within 1 to 2 weeks with the leg elevated. Driving waits until the brace is unlocked and quad control has returned, about 6 to 8 weeks for a right knee. Cycling and swimming from about 3 months, running at about 4 months if cleared, and sport at 5 to 6 months.
Protocol summary
Precautions: brace locked in full extension for walking and sleeping for about 6 weeks, with weight bearing as tolerated in the locked brace; knee flexion limited and advanced gradually, commonly to about 90° by 6 weeks; no active or resisted knee extension until cleared at about 6 weeks; no deep squatting; full passive extension maintained throughout.
Criteria: the protection phase ends with full passive extension and a straight-leg raise without lag; strengthening advances with full motion, no extensor lag and 70% strength; return to sport requires symmetric strength and functional testing, typically at 5 to 6 months with surgeon clearance.
Frequently Asked Questions
How soon after a quadriceps or patellar tendon rupture should it be repaired?
Within the first one to two weeks. The tendon ends are still mobile and healthy in that window and can be reattached directly to the kneecap. After several weeks the muscle retracts and the tendon scars, and the repair may need a graft or a lengthening to close the gap. A suspected rupture is seen the same week.
How long is the brace locked after tendon repair?
About 6 weeks, locked in full extension for all walking and sleeping. It is unlocked only for the supervised passive flexion exercises, since bending the knee passively within the set limit does not pull on the repair the way active straightening does. After 6 weeks it is unlocked for walking and then weaned.
Can you walk after quadriceps tendon repair?
Yes, from the first day, with weight bearing as tolerated in the brace locked in extension and crutches for balance. With the knee held straight the repair is not under tension, so walking is safe. Crutches are weaned once quad control returns and gait normalizes, usually as the brace is unlocked around 6 weeks.
Will my knee straighten fully after patellar tendon repair?
Full passive extension is maintained from the start and is the first goal of rehabilitation. Active extension returns more slowly as the quadriceps recovers, and a small extensor lag in the first months is common and expected to resolve with quad sets, straight-leg raises and strengthening.
When can I return to sport after extensor tendon repair?
Typically 5 to 6 months. Running and agility begin in the fourth month once strength is at least 70% of the other leg with no extensor lag, and return to sport requires symmetric strength and functional testing. Jumping sports, which load the extensor mechanism most, are cleared last.
This page is for general education and is not a substitute for a medical evaluation. The right procedure depends on your individual diagnosis, anatomy, and goals. Kevin O'Donnell, MD sees patients from Coral Gables, Miami, Brickell, Pinecrest and Coconut Grove at 475 Biltmore Way, and out-of-town patients by telemedicine.