Tendons are thick cords that attach the muscles to the bone, and participate in movement and joint stabilization. The quadriceps tendon is located at the front of the knee and connects the femoral quadriceps to the upper part of the patella. It is part of the extensor mechanism of the knee (essential for standing up) and plays a prominent role in knee flexion and extension.
What is a quadriceps tendon rupture ?
All tendons can suffer damage and even rupture. When a tendon ruptures, the joint loses all or part of its strength and ability to move. The tendons in the joints of the lower limbs are more prone to this type of damage as they are under greater strain.
Rupture of the quadriceps tendon is however rare and occurs most often in people over 40 years. Even if the presence of tendonitis is frequent prior to rupture, the latter is systematically traumatic. It is more common in athletes than more sedentary people and generally occurs as a result of an indirect trauma in the context of a fall – sudden flexion of the knee or intense contraction to avoid a fall – or when landing after a jump.
- Intense pain
- Edema (swelling) of the knee and bruising
- Functional impairment resulting in the inability of the person to straighten their knee on their own, lift their leg holding it straight or hold it straight against gravity.
- Palpable void above the patella
- More or less substantial migration of the patella downwards
The diagnosis is mainly clinical, but must be confirmed with an ultrasound. The diagnosis can be further consolidated with an MRI to determine the exact location and the severity of the rupture (partial or total rupture of the tendon).
The prognosis depends mainly on an early diagnosis to enable rapid surgical treatment.
Causes and contributing factors
- Intense sport, especially when it involves jumping,
- Aging: cell degeneration and gradual degradation of vascularization contributes to the deterioration of the tendons, which lose suppleness and resistance.
- History of inflammatory damage: tendonitis weakens the tendon and makes it more vulnerable to rupture.
- Fatigue, overuse,
- Outdoor activities in the cold,
- Dehydration that can result in high uric acid concentrations often implicated in inflammatory tendon damage,
- History of knee replacement with patellar medallion,
- Systemic diseases that weaken the tendons (erythematosus lupus, rheumatoid polyarthritis…).
Treatment is based exclusively on surgery and functional rehabilitation.
It, according to the location of the rupture, consists in suturing the ends of the ruptured tendon or reinserting the tendon in the bone.
Non-surgical treatments often lead to deformities of the knee and functional impairment characterized by a loss in ability to extend the knee – linked to calcification and tendon hypertrophy – which can be severe, painful and very debilitating.
However, this type of lesion is very rare and so is often under-diagnosed resulting in delayed surgical treatment, which is largely responsible for incomplete post-operative recovery.
The prognosis also depends on the initial quality of the tendons. With chronic inflammatory damage, it is possible that the knee does not recover full mobility after the operation.
Recovery can be total with prompt surgical treatment.
It must be gradual. It aims to restore tendon suppleness and strengthen muscle tone.
Walking with crutches is possible in the days following the operation, but the knee must be immobilized in a brace. Passive mobilization up to 30° is possible and helps reduce adhesion. However, it is necessary to wait 6 to 8 weeks before starting active flexion and extension exercises.
Full recovery of mobility generally takes about 6 months.