What is Perthes Disease?
Perthes disease or Legg-Calve’-Perthes Syndrome is a degenerative hip joint disease. It involves the loss of bone mass leading to hip joint collapse and deformity in the head of the femur and the socket of the hips. There is idiopathic avascular osteonecrosis of the femoral head epiphysis, which causes limited blood supply on the femur head that attaches to the socket of the hip bone.
Perthes disease is common in children, particularly in boys aged 5 to 12 years old. It can also lead to osteoarthritis in adults. Usually, only one hip is affected, however, up to 10% of cases have bilateral affectation of the hips.
Perthes Disease was named after Arthur Legg, Jacques Calve’ and Georg Perthes, thereby the name Legg-Calve’-Perthes Syndrome.
Perthes Disease Image
Image source: apteke.net
Symptoms of Perthes Disease
Symptoms of Perthes disease are associated with the collapse of the hip joint. These include:
- Pain on the hips, knees, and groin
There is severe pain on the knees, hips and groin as a result of the inflammatory response and swelling in the area brought about by tissue damage. The pain is more severe during hip and leg movements such as running, walking, standing, kneeling or stooping. The pain may radiate from the hips to the knees and groin because of referred pain. In addition, the pain may also be felt on the unaffected side because patients tend to put more weight on the normal leg and hip. Children often complain of soreness on the affected hip, which is sometimes mistaken to be part of the bone growth. Pain on the knees is also concentrated on the back area and not in the knee cap. Pain may last for hours and occur each day.
- Limited range of motion of the hip joint
Because of swelling and pain, there is restriction in the joint movement, which limits the mobility of the person. Movement causes more pain thereby the person limits its motion to prevent intense discomfort.
- Unstable gait
The affected site leads to shortening of the legs because of muscle contraction. As a result the patient will have significantly unequal leg length leading to difficulties in achieving a stable gait.
- Thigh muscle atrophy
Limited mobility of the legs leads to the disuse of the muscles on the affected side, which then leads to atrophy or the loss of muscle tone.
Causes of Perthes Disease
The exact cause of Perthes disease is unknown, which makes it idiopathic in nature. Possbile causes of Perthes Disease are associated with many factors such as:
Problems on the blood clotting mechanism may play a role in the formation of blood clot on the ligamentum teres femoris artery leading to lack of blood supply in the femur. Deficiencies in Protein C and S may also lead to lack of anticoagulation properties of the blood leading to clot formation.
Trauma is also a factor in the damage of the femoral head and the hip socket. Direct trauma to the hips may cause the condition.
Children who lack bone maturity as a result of endocrine disorders such as lack of growth hormone, leads to immature bones. This leads to risk for injury in the femoral head and hips, thereby may cause Perthes disease.
Limited calcium intake may lead to problems in the formation of the epiphyseal plates.
The main reason for symptoms of Perthes disease is the obstruction of blood flow to the femoral head. This may result from the constriction of the ligamentum teres femoris artery, which leads to lack of blood supply to the medial femoral circumflex artery, the main blood vessel that supplies the head of the femur.
Diagnosis of Perthes Disease
The diagnosis of Perthes disease is made suing imaging studies such as:
X-ray is the choice for diagnosing the condition. X-rays may reveal a flattened or fragmented femoral head, which verifies the diagnosis.
X – ray Imaging depicting flattening of femur located at right leg
Image source: childrensspecialists.com
MRI or Bone scan
These imaging studies may be done when X-rays are inconclusive. Positive results may reveal patchy areas of blood supply in the femoral head.
Treatment of Perthes Disease
The treatment for Perthes disease focuses on the prevention of further degeneration of the structures. Treatment regimens include:
Traction – Traction is the placement of pulling forces on the femur to release tension between the femoral head and the hip bone.
Leg braces – Leg braces are often used to provide external support to the hip and leg to allow for maximum mobility. Braces are often used for an average of 18 months.
Physical Therapy – Physical therapy is also important to allow for optimum functioning of the hip joint. It involves various exercises to promote mobility as well as preventing muscle atrophy. Physical therapy also helps patients regain the ability to walk normally following surgery.
Orthoses – Orthoses are special orthopedic devices used by people to maintain a normal anatomic position of the hips and leg. It promotes internal rotation of the femur with abduction of the legs by 45 degrees.
Use of mobility devices – Canes and crutches may be used by children to reduce pressure on the hip while walking. Removing the pressure enhances the blood flow to the hip joint.
Exercise – Proper exercises are also needed to improve the contraction of the muscles on the hips. Swimming is an example of which because it allows optimum motion of the legs. Tension usually happens during running and sports involving high impact motions of the foot. These should be avoided to prevent further injury.
Surgery – Surgery is commonly done when there is a severe damage to the hip joint. One procedure involved is hip replacement surgery to replace the damaged hip with an artificial orthopedic device. Hip replacement is commonly done to patients more than 50 years of age. For children, screws and plates may be placed on the hip joint to allow for proper alignment of the bones.
Hip replacement surgery to treat Perthes disease
Perthes Disease in Children VS Adults
Perthes disease is more common in children, but it can also persist until adulthood. Perthes disease that occurs in adults is usually a form of degenerative arthritis or osteoarthritis. Symptoms are similar with conditions in children and adults; however, more extensive treatment is done to adults such as hip replacement.