In congenital knee dislocation, patients’ lower legs are twisted and their knee joint surfaces are in insufficient contact. Noninvasive stretches are now available as therapeutic measures. Only in extreme cases does the joint need to be surgically repositioned.
What is congenital knee dislocation?
Medicine refers to a dislocation when there is a complete or incomplete loss of contact between two joint surfaces. Consequently, a congenital knee dislocation is a congenital joint malposition in the knee. This phenomenon thus involves the tibia and the femur. The malalignment results in hyperextension of the knee joint. The thigh muscles are shortened and the kneecap shifts outward. Often the cruciate ligaments are missing or valgus and rotational deformities occur. Chatelain first described this form of luxation in the 19th century. In some families a familial accumulation seems to have been observed. However, there is generally no talk of actual heritability. The prevalence of congenital knee luxation is reported to be about 1.5 per 100,000 newborns. Thus, knee dislocation is a relatively common phenomenon.
Causes
Congenital knee luxation occurs rather sporadically. The exact causes of the deformity have not yet been conclusively researched. Medical science assumes that hyperextended positions of the legs in the womb may play a causative role. Fibrosis is also a conceivable cause. This applies in particular to fibrosis of the quadriceps femoris muscle (four-headed thigh muscle). Since those affected by congenital knee dislocation often lack the cruciate ligaments, causal attention is also paid to this phenomenon. Nonetheless, muscle fibrosis due to hyperextended positions in the womb is the more likely cause. Indeed, unlike the missing cruciate ligaments, fibrosis is present in all patients of congenital knee dislocation. The congenital deformity may also occur in the context of various syndromes. Patients with Larsen syndrome and Down syndrome, for example, are often affected by the deformity. In these cases, the phenomenon may also have a hereditary component.
Symptoms, complaints and signs
The leading symptom of congenital knee dislocation can be seen with the naked eye. The patient’s lower leg is twisted due to the deformity, and the thigh muscle is shortened to a greater or lesser degree. The twisting of the lower leg is a dislocation from the knee joint, in which the lower leg shifts forward. Most often, the deformity occurs unilaterally, but bilateral variants have also been observed. The bilateral form appears to occur primarily as part of syndromes. If the congenital knee dislocation actually occurs in the context of a syndrome, the manifestation is accompanied by various symptoms. The accompanying symptoms then depend on the nature of the disease of origin. In Larsen syndrome, for example, multiple dislocations occur. Dysplasias of the skeleton also occur. In syndromes such as Zellweger syndrome, in turn, not only skeletal and joint abnormalities present, but also abnormalities of the brain and internal organs.
Diagnosis and course
Congenital knee dislocation can be recognized by visual diagnosis immediately after birth. The typical twisting of the lower leg is sufficient for a definite diagnosis. Sonography is often performed, which provides information about the exact position of the patella. X-rays may also show bony changes that are as typical of knee dislocation as the twisted position of the lower leg. To rule out the presence of a syndrome, various exclusion procedures and tests usually take place in addition to ultrasound and x-ray examination. The course of a knee dislocation strongly depends on the timing of the therapeutic intervention. For this reason, doctors usually recommend an intervention as soon as possible after the diagnosis has been made. The sooner the dislocation is repaired, the fewer movement restrictions remain in the patient’s further life. In most cases, the dislocation results in at least a somewhat limited ability to bend the lower leg, but this does not prevent the affected person from moving around. If, in addition to the dislocation, there is damage to the capsular apparatus, doctors usually speak of a somewhat less favorable prognosis.
Complications
Congenital knee dislocation is a painful knee malposition that can lead to acute sequelae. Normally, the kneecap sits immovable and placed by ligaments. In the case of knee luxation, however, it jumps out of the predetermined gliding path towards the outside of the knee. In most cases, it slides back into the correct position by itself. If sufferers ignore the symptom, complications accumulate after each dislocation. The joint swells and chronic osteoarthritis can develop. In addition, the pain can become so severe that walking and standing without problems becomes impossible. The leg literally buckles at the knee joint. The symptom appears around the age of 20. Women are more likely to be affected than men. The dislocation of the kneecap overstresses the ligaments, fine tissue, cartilage and bone. If the symptom is not treated early, ligaments and cartilage can tear, resulting in severe damage to the supporting apparatus and pain that extends to the femur. The medical diagnosis is made by means of X-rays or MRI. The resulting bone and ligament damage is surgically repaired. A subsequent physiotherapeutic measure helps the affected person to be able to put weight on his knee joint again. Depending on the severity of the findings, a special brace must be worn. Affected persons with congenital knee dislocation should therefore exercise their thigh muscles regularly to reduce the risk of complications.
When should you see a doctor?
Congenital knee dislocation is usually diagnosed right after birth. The doctor in charge will inform the parents about the deformity and refer them to a pediatric orthopedic center for further treatment. In most cases, it is possible to correct the knee luxation through orthopedic measures. Whether further surgery is subsequently required depends, among other things, on the severity and localization of the deformity. Further medical measures are necessary, for example, if a redression cast, i.e. manual correction, does not achieve a satisfactory result. The exact procedure varies from case to case. Parents should therefore consult regularly with the responsible physician and consider all medical options. If functional disorders of the affected knee occur later in life, a doctor must be consulted immediately. The affected person himself sometimes needs therapeutic support, since the gait disturbances that sometimes occur can lead to social exclusion and subsequently to psychological problems. Normally, however, no long-term consequences are to be expected with prompt treatment.
Treatment and therapy
Malalignment can be treated relatively effectively according to the current state of medicine. In patients of congenital knee dislocation, treatment is performed in a pediatric orthopedic center. The goal of therapy is to reposition the twisted joint, restoring the affected person’s mobility as much as possible. Often, this does not require surgery. Stretching may already have the desired effect in some circumstances. The patient is usually placed under anesthesia to stretch the shortened thigh muscle. This anesthesia is especially important given the tender age of the patient. A redression cast can be used to influence the position of the twisted joint. As a rule, sonographic progress controls are carried out regularly, during which the previous success of the joint repositioning is recorded. If satisfactory results cannot be achieved via a redression cast, surgical measures are often considered. In this regard, for example, surgical lengthening of the quadriceps may be considered. The exact procedure for surgical muscle lengthening depends on the individual case. Several procedures are possible. The extent of the deformity, as well as the quality of the capsular apparatus, can play a role in the selection of the surgical procedure, for example.
Outlook and prognosis
Due to this complaint, in most cases there are relatively severe restrictions in the movement of the patient. The lower leg of the affected person is usually severely twisted in the process, which likewise results in a shortening of the thigh muscle. This results in a severe malposition, so that ordinary activities in everyday life are made significantly more difficult by this disease.It is not uncommon for those affected to suffer from depression or other psychological upsets as a result of the restrictions. It has happened several times that mostly children are affected by teasing due to the malposition. This disease can also cause significant limitations and delays in school sports or in the child’s development. The disease is treated with the help of various therapies or by surgical intervention. This can limit most of the symptoms so that there are no significant restrictions in the patient’s everyday life. The life expectancy of the affected person is also not reduced by this disease. The condition does not heal on its own, so that without treatment there may be severe discomfort and limitations even in adulthood. As a rule, the affected person’s quality of life is greatly reduced as a result.
Prevention
Congenital knee dislocation cannot be prevented. However, because treatment options are now well advanced, there are hardly any impairments today that greatly reduce the quality of life of the affected person.
Aftercare
Knee dislocation is congenital. It can be corrected by therapies or surgery to the extent that there are hardly any restrictions in everyday life. The recurrence of knee dislocation with significant effects is therefore excluded. Aftercare must therefore pursue other goals. The aim is to maintain mobility in everyday life. Complete healing is not always possible. Sometimes a limited ability to bend remains. However, this need by no means lead to major restrictions in private life and work. Rather, it is important for patients to learn how to deal with the remaining deformity. Physiotherapists teach exercises. Sufferers can, for example, strengthen their thigh muscles. A range of exercise bikes is suitable for this purpose. Patients should also maintain leg mobility on a permanent basis. Short walks should be integrated into everyday life. It is not uncommon for children to be affected by knee luxation. They are regularly exposed to teasing in physical education classes. This condition can cause a psychological disorder that persists even after successful treatment. A doctor then regularly prescribes therapy to rebuild diminished self-esteem. Doctors first diagnose a knee dislocation at birth. X-rays and ultrasound examinations are useful for ongoing documentation of the condition.
Here’s what you can do yourself
The best thing to do in everyday life is to do light sports continuously. At home, it is recommended to exercise two to three times a week on a home trainer at a low level. This strengthens the thigh muscle, which is responsible for kneecap tracking. Exercising also helps develop a sense of proper flexor and extensor range of motion. Walking in the woods and doing small grocery shopping helps maintain leg mobility and can be easily incorporated into everyday life. When cleaning or making a bed, it is helpful to purchase a knee mat and place it underneath. This relieves the joint and no outside help is needed for these activities. In order to make all movement processes easier, it is useful to use the hands as an aid. When sitting down or standing up, it is advisable to shift the weight onto them and to be able to sit or stand by pushing off or cushioning. In case of pain in everyday life, it is advisable to stand still and manually test the patellar guidance and correct it if necessary. In most cases, it is then possible to continue walking without any problems. In case of nighttime problems, it is advisable to smear curd on the knee and apply a loose bandage. The most comfortable and least painful sleeping position is on the stomach.
