Quadriceps Tendon Repair

Why this approach — at MOS

Quadriceps tendon repair shares the same fundamental technical principles as patellar tendon repair: the repair must be strong enough to permit early motion, and the patellar height must be anatomically restored. We use large-diameter, high-strength sutures in Krackow locking configuration in two planes through the tendon body to maximize pull-out strength.

Patellar height restoration is confirmed fluoroscopically before tying sutures. The Insall-Salvati ratio (patellar tendon length to patellar height) is measured and compared to the contralateral knee. A patella left in too low a position (patella baja) causes patellofemoral pain and restricted flexion; a patella left too high (patella alta) is mechanically unstable. Getting this right at the primary repair is the most impactful technical decision.

We begin early motion protocols at 2 weeks (protected flexion to 30°, then 60°, then 90° over 6 weeks) rather than immobilizing for 6 weeks in extension — the evidence supports that early motion produces better final range of motion without increasing repair failure rates when adequate suture strength is used. Patients from across Montgomery County who undergo repair here follow the same in-house physical therapy protocol, coordinated directly with the surgical team.

Who is a candidate?

Indications

• Complete quadriceps tendon rupture — confirmed by physical examination (inability to actively extend knee, palpable gap above patella, patella in low position on lateral X-ray) and MRI
• All complete ruptures in patients medically fit for surgery

Contraindications

• Partial tear without extensor lag — may be managed conservatively with brace in extension and physical therapy
• Active infection
• Medically unstable patient in whom surgery must be deferred

Conservative Treatment First

Partial quadriceps tendon tears — where some layers remain intact and the patient can still extend the knee against gravity with some lag — are managed with a brace locked in extension for 6 weeks, followed by protected physical therapy. However, complete ruptures — defined by inability to actively extend the knee and a complete tear confirmed on MRI — do not heal reliably without surgery. The thick, multi-layered tendon architecture means that retraction occurs rapidly and repair becomes progressively more difficult with delay. Surgery within 1–2 weeks of injury yields the best outcomes. Beyond 4 weeks, mobilizing the retracted tendon becomes more challenging and outcomes deteriorate.

The procedure

What Is Quadriceps Tendon Repair?

Quadriceps tendon repair is urgent surgery that reattaches the quadriceps tendon — the large tendon above the kneecap connecting the thigh muscles to the patella — after it ruptures. Rupture completely eliminates the ability to extend (straighten) the knee. Repair should be performed within days to weeks of injury for the best outcomes and must not be delayed.

The quadriceps tendon is formed by the convergence of the four quadriceps muscles — the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius — into a wide, multi-layered tendon that inserts on the superior pole of the patella. It is the largest tendon crossing the knee joint and transmits enormous forces during stair climbing, squatting, and jumping. Rupture occurs when the force on the tendon exceeds its tensile strength — most commonly from an unexpected eccentric contraction (such as stumbling or landing awkwardly), or from a direct blow.

Quadriceps tendon ruptures are more common than patellar tendon ruptures and occur most frequently in men over 40, often with pre-existing tendon degeneration. Risk factors include age-related tendon degeneration, obesity, systemic diseases (chronic kidney disease, diabetes mellitus, systemic lupus, hyperparathyroidism), and prior corticosteroid injection. Unlike patellar tendon ruptures (which occur at a discrete insertion point), quadriceps tendon ruptures frequently occur through the degenerated mid-substance of the tendon just above the patellar attachment, leaving a broad, frayed tear.

Without repair, the quadriceps cannot extend the knee. The kneecap drops to an abnormally low position (patella baja) on X-ray, a gap is palpable above the patella, and the patient cannot perform a straight leg raise. These findings confirm the diagnosis. Urgent surgical repair is the only definitive treatment for a complete rupture.

What Happens During Quadriceps Tendon Repair?

Quadriceps tendon repair is performed at the ambulatory surgery center under general or regional anesthesia. The patient is positioned supine. A tourniquet is applied. An incision is made over the anterior knee above the patella.

The retracted quadriceps tendon end is identified and delivered into the wound. Frayed, degenerate tissue is trimmed back to healthy tendon. Heavy, braided non-absorbable sutures (such as No. 5 Ethibond or FiberWire) are woven through the tendon in a Krackow locking stitch pattern — typically two rows of sutures, one in each limb of the tendon edge. This distributes load across the full tendon width and prevents suture cut-through.

The superior patellar pole is prepared — the surface is freshened with a rongeur or burr to expose bleeding bone, which improves tendon-to-bone healing. Two or three bone tunnels are drilled through the patella from superior to inferior; the suture limbs are passed through these tunnels and tied over the anterior patellar cortex, drawing the tendon firmly down to the superior patellar pole. Alternatively, suture anchors placed in the superior patellar pole eliminate the need for drilling bone tunnels.

The repair is assessed for strength and correct patellar height — the patella should be at its normal position, matching the contralateral knee on intraoperative fluoroscopic comparison. The wound is closed and the knee is braced in extension.

Recovery timeline

Frequently Asked Questions