Knee contracture is a persistent decrease in the volume of movements in the joint. It is possible to limit both flexion and extension. The degree of contracture can vary significantly – from moderate restriction to almost complete immobility. Pathology is usually accompanied by external deformation and pain syndrome of varying severity. To clarify the diagnosis and identify the cause of contracture, radiography, CT, MRI, arthroscopy and other studies can be prescribed. Treatment can be both conservative and operative.
M24.5 Knee contracture
Knee contracture is a persistent restriction of movements caused by trauma, congenital malformation, inflammation, degenerative–dystrophic process or prolonged immobilization. It is a fairly widespread pathology, often becomes the cause of disability and disability. Orthopedic traumatologists are engaged in the treatment of contractures.
The most common causes of knee contractures are injuries and degenerative-dystrophic processes (gonarthrosis). In gonarthrosis, mobility restriction occurs as a result of gradually worsening changes in all joint structures, as well as violations of the shape of the articular surfaces of the femur and tibia. In case of knee joint injuries, contracture can be formed as a result of the action of several mechanisms. It is possible to directly damage the joint with a violation of its shape and the formation of scars in soft tissues (with intraarticular fractures), shortening of the quadriceps muscle due to prolonged stay of the limb in the extension position (with hip fractures and leg fractures fixed with a plaster cast), as well as a change in the structure of articular cartilage due to prolonged immobility.
It has been established that knee contracture can develop even with immobilization for 3 weeks. Every week of immobilization, muscle strength decreases by 20%. At the same time, in 6 weeks, the stiffness of the articular bag increases by about 10 times. That is, to make a normal movement, the patient has to exert much more strength despite the fact that his muscles are significantly weakened. Prevention of immobilization contractures is one of the most important tasks in hip and lower leg fractures. In order to avoid the negative consequences of prolonged immobilization, surgical methods of treatment (fixation with plates, rods and external fixation devices) are being increasingly used and early physical therapy sessions are prescribed.
In addition, the restriction of mobility of the knee joint may occur due to purulent arthritis and extensive burns with the formation of skin-tightening scars. Scarring after deep lacerated and lacerated wounds in the knee joint, on the anterior and posterior surfaces of the thigh and on the posterior surface of the lower leg are less often the cause of movement restriction. Among the congenital anomalies of the knee joint development, in which contractures can be observed, are congenital dislocation of the knee joint, hypoplasia and aplasia of the tibia.
Depending on the cause, there are two large groups of joint contractures: active (neurogenic) and passive (structural). Structural contractures occur when there is something that prevents movement in the joint. Neurogenic contractures are a consequence of a violation of innervation and develop in paralysis, paresis and some mental illnesses.
Depending on the localization of the obstacle , all structural contractures are divided into:
- Arthrogenic – with deformities of the joint.
- Myogenic – with shortening of muscles.
- Desmogenic – in the formation of connective tissue scars.
- Dermatogenic – with the formation of scars on the skin.
- Immobilization – with prolonged restriction of mobility.
Taking into account the causes of neurogenic contractures are divided into:
- Central neurogenic – caused by injuries and diseases of the brain and spinal cord.
- Psychogenic – arising from hysteria.
- Peripheral – developing with damage to peripheral nerves. They can be painful, reflex, irritative-paretic or are the result of violations of autonomic innervation.
In addition, depending on the type of restriction of movements in traumatology and orthopedics, flexion (the joint is reduced in the flexion position) and extensor (the joint is reduced in the extension position) contractures are distinguished.
The main symptom of knee contracture is a restriction of flexion or extension. As a rule, there is a more or less pronounced deformation of the joint. One or more of the following signs may be observed: swelling, impaired support, joint pain, shortening and forced position of the limb. Otherwise, the clinical picture depends on the underlying disease. With the long-term existence of contracture, signs of arthrosis of the knee joint are usually detected. To assess the severity of contracture, the volume of active and passive movements is measured.
The diagnosis of contracture is made on the basis of an external examination. To clarify the cause of the pathology, the doctor finds out the anamnesis of the disease and prescribes an X-ray of the knee joint. If scarring of soft tissue structures is suspected, the patient may be referred for arthroscopy, CT or MRI. If neurogenic contracture is suspected due to damage to peripheral nerves, brain or spinal cord, a consultation with a neurologist or neurosurgeon is indicated. With hysterical contractures, a consultation with a psychiatrist or a psychotherapist is necessary.
Treatment can be both conservative and operative and carried out in a trauma center, traumatology or orthopedic department. The main methods of conservative therapy are physical therapy, physiotherapy (electrophoresis, shock wave therapy), massage, mechanotherapy and bloodless correction of the limb position using replaceable plaster bandages and special fixing devices. If conservative treatment is ineffective, surgical operations are performed.
Surgical intervention can be carried out through open access or using arthroscopic equipment. The purpose of the operation is to restore the shape of the articular surfaces, remove scar tissue or lengthen muscles. With significant destruction of the articular surfaces and the preservation of the muscles of the thigh and lower leg, knee replacement is performed. In some cases, arthrodesis of the joint in a functionally advantageous position becomes the optimal solution. In the postoperative period, physical therapy is prescribed. Massage and physiotherapy procedures are used to increase muscle tone and improve blood supply.
The effectiveness of the treatment of neurogenic contractures largely depends on the success of the therapy of the underlying disease. With flexion contractures that have arisen as a result of cerebral or spinal paralysis, splints are applied to straighten the limb or devices with weights are used. With hysterical contractures, psychiatric treatment is carried out or various psychotherapeutic techniques are used.
Prognosis and prevention
The prognosis largely depends on the underlying disease, the severity of pathological changes in the joint and surrounding tissues. Fresh immobilization contractures with adequate treatment and regular physical therapy, as a rule, lend themselves well to conservative correction. With long-standing contractures of any genesis, the prognosis is less favorable, since over time changes in the joint worsen, scar degeneration develops not only damaged, but also previously healthy tissues, secondary arthrosis occurs.