Legg-Calve-Perthes Disease Coxa Plana Osteonecrosis of the femoral head

Affects the head of the femur resulting in inadequate supply of blood to the epiphysis. Weakness in the bone which eventually breaks down very easily and dies.

Neither caused by injury nor by general blood vessel problem Disease usually affects only one hip, both the hips can also be affected in some cases The recovering ability of the affected bone is very poor. The blood vessels may grow again over several months returning the blood supply to the necrosed or dead bone tissue and the femoral head starts to remodel correcting the deformity

. The pelvis and thigh bone form a ball-and-socket joint This process is similar to healing of the common types of fractures, but takes a longer duration to heal completely.

Age: •Sex: •Race: •Family History: Affects children in the age group of four to eight years. •Sex: Boys are five times more girls. •Race: More commonly affects white children than black children. •Family History: .

Symptoms : •Stiffness or pain in the thigh, knee, hip and groin. •Gradual worsening of limping. •Decreased range of motion of the affected hip. •Stiffness in the affected hip. •The affected leg may look shorter than the healthy leg. •The affected leg may also become slightly thinner eventually due to the thinner thigh muscles because of less usage when compared to thigh muscles in the healthy leg.

Risk factors : * Positive family history * Low birth weight * Abnormal birth presentation * Second hand smoke * Asian, Inuit, and Central European decent

Prognosis : Important prognostic variables Bad prognosis : * Age of patient (bone age) at presentation * Sphericity of femoral head and congruency at skeletal maturity Bad prognosis : * Age (bone age) > 6 years at presentation * Chronological age 5-7y better than age 8-9y * Female sex * Decreased hip range of motion (abduction) with adduction contracture * Heavy patient * Longer duration from onset to completion of healing * Stiffness with progressive loss of ROM

Treatment : Concentrates on keeping the femoral head as round as possible in order to help the hip to function appropriately. The socket works like a mold for the fractured femoral head during the healing process. The healing time varies with each patient depending upon the severity of the affected bone. The treatment process usually takes couple of years or more.

Diagnosis : * Physical examination * X-rays * Bone scan * Magnetic resonance imaging (MRI)

Differential Diagnosis : Multiple epiphyseal dysplasia Spondyloepiphyseal dysplasia Sickle cell disease Gaucher disease Hypothyroidism Meyers dysplasia

Nonsurgical treatments : Rest: Decreasing the amount of stress and weight on the affected bone helps in slowing down the damage. Restricting heavy amount of physical activity and using crutches may help in keeping the weight off from the affected joint. Traction: Episodes of traction and bed rest are also helpful to treat severe pain.

Casting: keep both the legs spread widely apart for about four to six weeks of duration. Exercises: Stretching and strengthening exercises help in keeping the hip more flexible. Exercises not only help in improving range of motion and muscle strength, but also maintain the balance and coordination of the joint.

Physical Therapy: •Joint mobilization Speeding up the healing process and obtaining optimal results. Decreases the likelihood of recurrences in the future. •Joint mobilization •Exercises to improve strength and flexibility •Activity modification and training •Appropriate plan for return to activity •Hydrotherapy

Surgery: Contracture Release: Loose Body Removal: Hardware Implants: * Nonsurgical treatments fail * Above seven years of age Contracture Release: Lengthen out tissues and help restore normal flexibility of the hip joint Loose Body Removal: Remove these bits of tissues and help the hip joint to function smoothly. Hardware Implants: Implants may include plates, wires, and screws

Shelf or Chiari osteotomies are also considered when the femoral head is no longer containable

Further reference : Molloy MK, Macmahon B. Birth weight and Legg-Perthes disease. J Bone Joint Surg Am. 2010 Apr;49(3):498–506

Q & A Dr. 熊永萬 Dr. Bear