Patellar Tendon Tear and Rupture Repair
A complete patellar tendon rupture is one of the few knee injuries where patients know immediately that something serious has happened. The tendon connecting the kneecap to the shin bone is what allows the knee to straighten against resistance, and when it tears completely the leg simply stops working in a way that is impossible to mistake.
Steven Struhl, MD is board certified in orthopedic surgery and holds separate board certification in sports medicine, has practiced in New York since 1991, and completed his sports medicine fellowship at Penn State University. A complete extensor mechanism rupture is a time sensitive injury, and it is repaired best when it is repaired early.
Patellar Tendon Rupture Symptoms
- A Pop at the Moment of Injury: frequently audible, and almost always felt.
- Inability to Straighten the Knee: the defining sign, since the extensor mechanism is disconnected.
- A Palpable Gap: a defect felt below the kneecap where the tendon should be.
- High Riding Kneecap: the patella pulled upward by the quadriceps with nothing anchoring it below.
- Immediate Swelling and Bruising: developing rapidly at the front of the knee.
- Giving Way: the knee buckling on any attempt to bear weight.
An inability to perform a straight leg raise, meaning lifting the heel off the bed with the knee straight, is the finding that separates a complete rupture from a partial tear and it should be checked in every case.
How a Patellar Tendon Tears
- Sudden Eccentric Load: landing from a jump or stumbling, where the quadriceps contracts hard against a bending knee.
- Direct Blow: a laceration or an impact to the front of the knee.
- Preexisting Tendinopathy: chronic patellar tendinitis weakening the tendon before it fails.
- Systemic Conditions: diabetes, chronic kidney disease, rheumatoid arthritis, and lupus all reduce tendon strength.
- Medication: corticosteroids, including injected, and fluoroquinolone antibiotics.
- Prior Knee Surgery: particularly patellar tendon graft harvest for ACL reconstruction.
Complete rupture in a healthy tendon requires substantial force. In a tendon compromised by disease or medication, considerably less will do it.
Diagnosis and Imaging
The diagnosis is largely clinical, and the palpable gap plus the inability to extend against gravity establish it. Radiographs confirm the high riding patella and rule out an avulsion fracture where the tendon has pulled bone away with it. MRI or ultrasound confirms whether the tear is complete or partial and shows exactly where it has failed, which determines the repair technique. Partial tears with an intact extensor mechanism are treated in a brace rather than operated on.
Patellar Tendon Repair Surgery
A complete rupture is a surgical injury. The tendon does not reconnect on its own, and the interval between injury and repair matters, since the quadriceps begins to contract and the tendon ends retract within a few weeks. Repair within two to three weeks is considerably more straightforward than repair at three months.
- Direct Repair: heavy sutures passed through the tendon and secured through bone tunnels in the patella or with anchors.
- Avulsion Repair: where the tendon has pulled off bone, reattaching it to a prepared surface.
- Augmentation: in chronic or revision cases, reinforcing the repair with graft tissue.
- Tension Assessment: patellar height is checked intraoperatively, since a repair that is too tight or too loose changes how the knee works permanently.
Recovery After Patellar Tendon Repair
- Weeks One to Two: braced in extension, weight bearing as tolerated, with the repair protected.
- Weeks Two to Six: progressive flexion within limits the repair tolerates, quadriceps activation begun early.
- Weeks Six to Twelve: brace weaned, full motion restored, strengthening advanced.
- Months Three to Six: strength rebuilt toward the uninjured side, with running introduced late.
- Months Six to Nine: return to sport, guided by strength testing rather than by the calendar.
Most patients regain full extension and functional strength. Some retain a small extension lag or a measurable quadriceps deficit, and the patients who do best are consistently the ones repaired early and rehabilitated consistently.
Schedule a Patellar Tendon Consultation in New York City
A knee that cannot be straightened after an injury should be evaluated the same week rather than waiting to see whether it settles, because the repair is easier and the result is better when it is done early. Dr. Struhl treats extensor mechanism injuries and knee conditions at his Manhattan and White Plains offices. Contact our practice to schedule an appointment.
