Introduction
Perthes disease is also known as Legg–calve–perthes disease, coxa plana,pseudocoxalgia. the disease is self-limiting in nature and the head revascularizes and hardens again after sometime, it never regains the normal shape if deformed. The whole process takes about 2–4 years.
Definition
Perthes disease is a disease of childhood characterized by avascular necrosis of the femoral head. The exact cause is unknown. However, a local disturbance of blood supply is thought to be the main causative factor.
Etiology
the epiphysis of the femoral head becomes necrotic and soft. Hypertrophy of the articular cartilage, particularly on the medial side of the head of the femur, pushing the femoral head laterally outside the lateral edge of the superior (weight-bearing) part of the acetabulum . In this state, it is susceptible to deformation if subjected to the stresses of weight bearing.
Clinical Features
Common signs and symptoms include:
- Reduced range of motion in the hip joint particularly abduction and medial rotation.
- Pain in the hip, thigh, groin, or knee, which may be intermittent.
- Limping, often the first noticeable symptom.
- Muscle atrophy in the thigh and buttock on the affected side.
- Leg length discrepancy can be noticeable.
Investigation
Diagnosis typically involves:
- Physical Examination: Assessing gait, range of motion, and muscle strength.
- X-rays: Radiograph confirms the diagnosis and shows the stage of the disease (Grades I–IV).
- MRI (Magnetic Resonance Imaging): More sensitive in early stages to detect avascular necrosis and assess the level of damage.
- Bone Scans: Can identify areas of decreased blood flow.
Risk Factors
Key risk factors include:
- Age: Most commonly affects children aged 4-12.
- Sex: Boys are affected more often than girls (approximately 4-5:1 ratio).
- Secondhand Smoke Exposure: Possible link, though more research is needed.
- Low Birth Weight: Some studies suggest a correlation.
Physiotherapy Management
Physiotherapy plays a crucial role in managing Perthes disease, aiming to maintain hip mobility, contain the femoral head within the acetabulum, and prevent deformity. This includes:
- Pain Management: : Muscular spasm due to the disease process is the primary cause of pain and deformity. It can be controlled by applying cryotherapy techniques or moist heat with the leg maintained in traction and gentle active toe and foot measurement with traction on.
- Intermittent compression of the joint: It can be achieved by early slow relaxed passive movements. This helps in improving nourishment of the joint cartilage, moulding the joint surfaces and maintaining normalcy of the soft tissues.
- Range of Motion Exercises: The full range of movements of hip extension, abduction and internal rotation is carried out and measured at regular intervals. These movements usually get limited due to the adaptive resting posture of the limb in flexion, abduction and external rotation.
- Bracing/Casting: A special brace (Scottish rite brace) allows flexion of the hip joint while it is maintained in abduction. 2. The second method is the Petrie plaster method . This maintains the hip in 30 degrees of abduction and 20 degrees of internal rotation, with 15 degrees of flexion at the knees.
- Gait Training: non–weight-bearing standing and walking are to be taught in parallel bars. This could be progressed to a walker and then to axillary crutches by using a special Synder sling. This allows non– weight-bearing ambulation on the affected leg.
- Activity Modification: Limiting high-impact activities.
Conclusion
Legg–Calve–Perthes disease is the idiopathic osteonecrosis or AVN of the femoral head and is commonly seen in the age group of 5–7 years. The child complains of pain in the groin, which may radiate down to the knee; the child walks with an antalgic gait. With early diagnosis, consistent medical supervision, and dedicated physiotherapy, most children achieve a good outcome, though long-term follow-up is essential to monitor for potential complications like osteoarthritis.