The parents of an 8-year-old male bring their child in for evaluation of a painless limp that they have noticed for the past 6 months. Initially, they thought the limp would go away; however, it has become more pronounced over the past 2 to 3 months. There is no history of traumatic injury. He has minimal pain but limited rotational motion of the hip (particularly abduction and internal rotation) and appears to be younger than his stated age. An initial AP x-ray of the hip is shown in Figure 42-1.
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What is the diagnosis?▶
What are the bad prognostic indicators of this disease/injury?▶
What are the current treatment options?Vignette 42: Answer
The diagnosis is Legg-Calvé-Perthes disease, which is a childhood disorder that affects the hip. The disease most commonly occurs in children aged 5 to 8 years, with a male:female ratio of 5:1. There is a 10% to 15% incidence of bilateral disease, and children often appear to be younger than their chronologi- cal age.96 Legg-Calvé-Perthes disease is essentially an unknown cause for ischemic necrosis of the femoral
head. Modern proposed etiologies include type II collagen mutations (missense mutation glycine for serine codon replacement of COL2A1) and inherited thrombophilia (factor V Leiden, increased protein C or S, and deficient antithrombin III).96 Although Legg-Calvé-Perthes disease is often well tolerated at a young age, it
is estimated that more than 50% of patients will develop disabling hip arthritis in the sixth decade of life.96
Physeal changes are often found in the anterior part of the femoral head.
Waldenstrom reported 4 x-ray stages for Legg-Calvé-Perthes disease: initial (seen as early femoral head opacities), fragmentation (1 year long), reossification (3 to 5 years long), and healed. Stulberg classified femoral head shape in correlation with future radiographic signs of OA at maturity for patients with Legg- Calvé-Perthes disease: type I, normal hip (low risk of OA); type II, spherical head with enlargement, short neck, or steep acetabulum (16% with radiographic evidence of OA at 40-year follow-up); type III, nonsperhi- cal femoral head (58% with radiographic findings of OA); type IV, flat femoral head (75% with radiographic findings of OA); and type V, flat head with incongruent acetabulum (78% with radiographic findings of OA).
Other classification systems to describe the femoral head and prognosis include the Catterall classifica- tion, which includes the following groups: group I (anterior head involved only), group II (anterior head involved only with a sequestrum), group III (only a small part of epiphysis not involved), group IV (total head involvement). Catterall head-at-risk signs include lateral subluxation, lateral calcification, diffuse metaphyseal reaction, horizontal growth plate, and Gage sign (v-shaped defect at lateral metaphysis). The last classification system is the lateral pillar (lateral 15% to 30% of femoral head)/Herring classification: group A (little head involvement and good outcome), group B (> 50% of lateral pillar height maintained leads to good outcome in those younger than 6 years), and group C (< 50% of lateral pillar maintained yields poor prognosis in all age groups).
When Legg-Calvé-Perthes presents in a child younger than 6 years, the long-term results are typically good with nonoperative management. Bad prognostic indicators include age older than 8 years, lateral head subluxation, metaphyseal cysts, group C lateral pillar classification, 2 or more head-at-risk signs, female sex, poor ROM, and premature physeal closure.
Initial treatment depends on the age of presentation and radiographic findings. A child who presents at age 9 years typically undergoes a more aggressive approach than a child who presents at age 4 years. The mainstay of management is nonoperative treatment for children younger than 6 years; children aged 6 to 8 years are in a gray zone, and children older than 8 years will require surgery (femoral and/or acetabular osteotomy). In our case, the child is presenting at 8 years old, and consideration for containment of the head should include femoral or acetabular osteotomy vs bracing, physical therapy, and close monitoring. The main goal is containment of the hip, so regardless of the age of presentation, surgical intervention is recom- mended if the hip begins to show signs of subluxation. In addition, pain relief and restoration of motion are paramount to a successful outcome. Again, in a child who presents at younger than 6 years of age, surgery is almost never performed.
You will never see bilateral Legg-Calvé-Perthes in the same stage. One hip may be in the fragmentation phase while the other is in the reossification phase. If you see bilateral Legg-Calvé-Perthes disease in the same stage, be aware of the diagnosis of multiple epiphyseal dysplasia.
Why Might This Be Tested? Legg-Calvé-Perthes disease is a common cause for a painless limp in a child.
A common answer for this disease management is nonoperative treatment, and the question writers love this option. There are distinct prognostic indicators; bad prognostic indicators include age older than 8 years, group C lateral pillar classification, 2 or more head-at-risk signs, female sex, poor ROM, and premature phy- seal closure, making this an ideal topic for questions.
Patients younger than 6 years will not require surgery and will have a good prognosis, whereas ages 6 to 8 years is a gray zone and patients older than 8 years will need surgery. Know the Catterall, Stulberg, and lateral pillar classification schemes. The key for manage- ment of Legg-Calvé-Perthes disease is containment of the femoral head in the acetabulum.