Qaudriceps Tendon Tear

Question 1

Etiology

Answer 1

Quadriceps tendon tears have a positive correlation with age and multiple medical comorbidities. This injury historically is more prevalent in males, with the age after 40 years. This is in opposition to patellar tendon tears, which commonly occur before age 40, and are often related to sports injuries.

A muscle rupture often happens during a high impact action with a bad landing. During a landing there is a heavy load on a knee in flexion and the foot is planted on the ground (jump). The Quadriceps muscle makes a rapid, eccentric contraction. Other mechanism is caused by a force straight on the anterior side of the knee (fall). Patients typically present with acute knee pain, swelling, and functional loss following a stumble, fall, or giving way of the knee

Question 2

Risk factors

Answer 2

Most quadriceps tendon tears happens because the tendon is weakened.

Tendinitis: inflammation of the tendon causes weakening and maybe even little strains.
A poor blood supply to the tendon due to diseases also weakens the tendon.
Chronic diseases

Secondary hyperparathyroidism which causes bone resorption which causes weakening of the fibro-cartilaginous junction between the tendon and bone tissue.
Chronic renal failure ; this can cause connective tissue elastosis which is suggesting for a weakening of the tendon.
Systemic lupus erythematosus (SLE), gout, leukemia, rheumatoid arthritis, diabetes mellitus, obesity, infections and metabolic diseases have a negative effect on the strength of the tendons.
Drugs abuse also have/has a degenerative effect on muscle tendon:

Corticosteroids usage has been linked to an increase of muscle and tendon weakness.
Fluoroquinolones, a special antibiotic is related to tendon ruptures.
Other factors such as knee surgery and immobilization also increase the chance, because the strength and flexibility of the muscle and tendon decreases.

Question 3

Characteristics/ clinical presentation

Answer 3

There is often a popping or tearing feeling at the time of event. Some patients are able to walk following this injury, but many cannot. The patient will be unable to straight the knee without help when the tendon is completely ruptured. Most of the patients present with acute knee pain, swelling and there is a palpable defect at the site of the tear.You can feel a dent/gap just proximal of the patella (the suprapatellar area) where the quadriceps tendon was torn. The quadriceps will be sensitive and cramping.

There is a hematoma visible around the knee.Usually, obvious suprapatellar swelling, ecchymosis, and tenderness are present. The patella may sag or droop as a result of the quadriceps tendon tear but swelling may obsure this finding. There is a function loss especially there will be a loss of extension and also loss of stability. If the patient is not seen in the acute phase, diagnosing the rupture becomes more difficult, and it can be easily missed.

Many patients are thought to have only simple knee sprains during their examination in the emergency room and are not given appropriate, immediate follow-up

Question 4

Exam

Answer 4

During the inspection you can see swelling around the suprapatellar area, there is a hematoma.
When you start the active examination you can immediately see that there is functional loss.Patients may have frequent buckling of the knee and difficulty with stair climbing.Patients may be able to ambulate but will do so with a gait demonstrating knee stiffness and elevation of the hip to accommodate the swing-through phase.

Testing for full, active extension against gravity is the most important aspect of the examination. The patient will be unable to perform a straight leg raise.Extension lags of varying degrees are seen, depending on the amount of retinacular damage. In incomplete ruptures, the patient may be able to fully extend the knee from the supine position but not from the flexed position. If only tendinitis is present, no extension lag should be noted with any test position. It is also important that you examine the contralateral knee to rule out bilateral rupture.

Results of neurologic examination are normal except for decreased quadriceps motor function and an absent patellar reflex