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Quadriceps Tendon Rupture

Quadriceps tendon rupture is an uncommon occurrence among the immediate sources of knee pain, yet its impact can be considerably incapacitating. It’s more common than patellar tendon rupture.

The quadriceps tendon ruptures usually occur within 2 cm proximal to the superior pole of the patella. In patients less than 40 years of age, quad tears are most often mid-substance, whereas in those over the age of 40 years rupture usually occurs at the bone–tendon junction. With male more commonly injured than female.

Mechanism of Injury

The extensor mechanism consists of the quadriceps muscle complex, quadriceps tendon, patella, patellar tendon and patellar tendon insertion into the tibial tubercle. Disruption of the extensor mechanism occurs during a sudden eccentric contraction of the quadriceps muscles with the foot planted and the knee flexed.

Extensor mechanism disruptions commonly occur in patients with systemic illness such as diabetes or renal failure, or with the use of exogenous steroids. Corticosteroid injections for treatment of patellar tendinitis are associated with an increased incidence of rupture. Early recognition of this injury is crucial because results of early surgical repair of both quadriceps and patellar tendon ruptures are more favorable than late repair or reconstruction.

See Also: Patellar Fractures | Broken Kneecap

Risk factors for Quadriceps Tendon Rupture include the following:

  1. Renal failure
  2. Diabetes
  3. Rheumatoid arthritis
  4. Hyperparathyroidism
  5. Connective tissue disorders
  6. Steroid use
  7. Intraarticular injections

Quadriceps Tendon Rupture Symptoms

Patients usually present with sensation of a sudden ‘pop’ while stressing the extensor mechanism and pain in the knee. There is usually tenderness and a palpable defect proximal to the superior pole of the patella. With a complete rupture, the patient will be unable to perform a straight leg raising effort. A partial tear frequently results in the patient’s ability to lift his or her leg, but with a considerable lag.

See Also: Patellar Dislocation


Anteroposterior and lateral radiographs with the knee in 30° of flexion is obtained. Distal displacement of the patella (patella baja) may be observed.

On the flexion lateral radiograph, the lower pole of the patella should be at the level of the line projected anteriorly from the intercondylar notch (Blumensaat line).

In cases of an unclear diagnosis, an MRI or an ultrasound may be obtained.

quad tendon rupture xray
quad tear mri

Quadriceps Tendon Tear Treatment

An incomplete tear with active full knee extension is managed with immobilization of the knee in extension for 4–6 weeks.

Complete ruptures require repair. The quadriceps tendon is reapproximated to bone using non-absorbable sutures passed through bone tunnels. The tendon is repaired close to the articular surface to avoid patellar tilting:

  • Mid-substance tears are treated with end-to-end repair.
  • A distally based partial-thickness quadriceps tendon turned down across the repair site (Codivilla technique) helps to reinforce the repair.
  • Chronic tears require a V–Y advancement of a retracted quadriceps tendon.
quadriceps tendon repair
quadriceps tendon repair technique

References & More

  • Siwek CW, Rao JP. Ruptures of the extensor mechanism of the knee joint. J Bone Joint Surg Am. 1981 Jul;63(6):932-7. PMID: 6985557. Pubmed
  • Mercer’s Textbook of Orthopaedics and Trauma, Tenth edition.
  • Millers Review of Orthopaedics -7th Edition Book.
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