CASE                                7                               

A 6-year-old boy presents to your office with a limp. It is difficult for you to examine him because he will not stay still. He is thin, 3′10″ tall with a Trendelenburg gait. He has normal, painless range of motion of his feet, ankles, and knees with limited abduction of his right hip. Radiographs are normal. Laboratory values demonstrate an erythrocyte sedimentation rate of 36.

What is the next step?

1. Aspirate hip

2. Ultrasound hip

3. Irrigation and debridement of hip

4. Technetium 99m radionucleotide scan

Discussion

The correct answer is (D). This is a picture of Legg–Calvé–Perthes, a condition often affecting boys between the ages of 4 and 8 and often they are of short stature and hyperactive. They present with a painless limp, limited abduction of the hip, and normal radiographs. The ESR may be elevated and the Technetium 99m radionucleotide scan is positive in the early stages of the disease.

Bone scan demonstrates activity and a diagnosis of Legg–Calvé–Perthes is made. What is the best treatment option?

1. Bedrest, adductor stretching

2. Proximal varus femoral osteotomy

3. Shelf osteotomy

4. Valgus-flexion femoral osteotomy

Discussion

The correct answer is (A). Children <6 with <50% head necrosis and those <8 with lateral pillar A or B do well regardless of the treatment. Answer A is the least invasive.

The next boy is 9 years old with a painless limp and >50% fragmentation of the femoral head. What is the best treatment option?

1. Bedrest, adductor stretching

2. Proximal femoral osteotomy

3. Shelf osteotomy

4. Valgus-flexion femoral osteotomy

Discussion

The correct answer is (B). The Norwegian Study Group found that a femoral osteotomy in a child >6 years old and >50% of femoral head necrosis did better than without surgery. Surgery during the fragmentation phase also decreases the length of the disease, femoral head extrusion, and metaphysical changes in about one-third of cases.

He elects not to have surgery. Twelve years later he presents with an incongruent joint, coxa magna, lateral hinging, and no evidence of arthritis. What is the most important predictor of outcome on examination?

1. Incongruent joint

2. Coxa magna

3. Lateral hinging

4. No evidence of arthritis

Discussion

The correct answer is (A). Patients with aspherical, incongruent joints develop osteoarthritis in their 40s. Coxa magna or lateral hinging has not been shown to increase the development of arthritis. At the age of 21, the cartilage space should still be present on x-ray.

At this time, what is the best salvage option for his hip?

1. Observation

2. Proximal varus femoral osteotomy

3. Shelf osteotomy

4. Valgus-flexion femoral osteotomy

Discussion

The correct answer is (D). The valgus-flexion femoral osteotomy with or without an acetabular procedure to correct the dysplasia or retroversion has been shown to decrease pain in symptomatic hips after skeletal maturity with impingement, instability, and poor range of motion without signs of arthritis.

Objectives: Did you learn...?

Clinical presentation of a child with Legg–Calvé–Perthes disease? Treatment for LCP at different stages of severity?

Risk of future arthritis at younger age?