pathology: patellar tendon rupture

yogabook / pathology / patellar tendon rupture

Patellar tendon rupture

A patellar tendon rupture is a tear of the ligament commonly referred to as the patellar tendon, the ligamentum patellae. It is often preceded by a long-standing disorder, most commonly patellar tendinopathy (jumper’s knee).

Injuries to the patellar tendon can occur traumatically or as a result of a forceful eccentric load on a contracted quadriceps. Degenerative changes increase the risk of a partial or complete rupture.

In a patellar tendon rupture, patella alta may be seen, whereas in a quadriceps tendon rupture, patella baja may be present. Radiographs may show traction osteophytes, and ultrasound may show an oedematously thickened tendon. These findings can also occur in asymptomatic individuals, particularly older patients. Imaging findings and clinical presentation may therefore differ considerably. MRI is particularly useful for excluding differential diagnoses.

In both tendon ruptures, a radiograph should be obtained to exclude a patellar fracture. A transverse patellar fracture can cause either patella alta or patella baja; such a change in patellar position is pathognomonic. Even in this situation, a radiograph is still required to define the fracture precisely before the patella is treated surgically.

The treatment of an underlying patellar insertional tendinopathy remains conservative for the time being; if treatment is unsuccessful after six months, an alternative approach may be considered. Conservative treatment is particularly promising when pain occurs only after activity or during and after activity.

The relevant musculature should be assessed. Hypertonus of the quadriceps is common, and reduced muscle performance may also predispose to injury. A study of basketball players aged 14 to 18 years found an association with shortening of the hamstrings.

There is no positive evidence base for NSAIDs; moreover, these drugs may impair tendon healing and increase the risk of rupture. They should therefore be used cautiously in tendon injuries. Foot deformities, however, should be treated. Regular daily exercise, sometimes several times a day, is one of the most important pillars of treatment. The movements should be performed slowly and correctly; the eccentric component can be substantial, and flexion may be limited to 60 degrees.

As with many other insertional tendinopathies, pain up to NRS 3 or 4 during rehabilitation exercise, with an appropriate subsequent response, may be tolerated. NSAIDs can provide short-term pain relief, but should be used cautiously in tendon injuries because they may impair tendon healing and increase the risk of rupture.

Neovascularisation can be treated with sclerotherapy if appropriate. A possible beneficial effect of PRP has been described; however, a proven advantage over extracorporeal shockwave therapy has not been sufficiently established.

Complete patellar tendon ruptures are generally treated surgically, whereas partial ruptures are managed according to their extent and severity. Complete ruptures of the quadriceps tendon are also treated surgically. Partial ruptures of the quadriceps tendon, however, can be treated conservatively with appropriate immobilisation.

In the conservative treatment of quadriceps tendinopathy, extracorporeal shockwave therapy should be dosed appropriately, as excessive treatment can cause additional tendon damage.

Risk factors

Symptoms

  • Loud popping sound at the time of the tear
  • Marked loss of strength when extending the knee joint
  • Swelling, haematoma
  • Infrapatellar pain
  • Palpable discontinuity
  • Patella alta

Diagnosis

  • Clinical examination: palpation
  • History
  • Ultrasound, MRI

Treatment

  • Activity modification, immobilisation
  • Complete ruptures: surgery
  • Partial ruptures according to extent and severity

Risk factors

Diagnosis and treatment

Guidelines