Developmental dysplasia of the hip and occult neurologic disorders

Abstract

Developmental dysplasia of the hip (DDH) is a neonatal condition with various causes. Neuromuscular dysplasia of the hip (NDH) is a sequel of neuromuscular disease, and generally presents later in childhood than DDH. Some evidence, however, supports a concept of a neuromuscular etiology of DDH: (1) a high prevalence of spinal dysraphism in DDH; and (2) abnormal sensory evoked potentials in 31% of DDH patients. To explore this suggestion we ascertained the presence of neuromuscular disease within a cohort of DDH patients, and asked whether the neuromuscular condition is the initial etiology of the dysplasia or a coincidental finding. We retrospectively reviewed patients presenting with DDH. Only those with an initial diagnosis of DDH and a subsequent diagnosis of a neuromuscular condition were assessed. Fifteen of 560 patients fulfilled the criteria, however the presence of true DDH within this group was minimal, as several cases emerged as early presenting NDH. We therefore believe it unlikely DDH has a substantial neurological etiology.

Level of evidence: Level III, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Fig. 1A–D

Radiographic evidence charting the acetabular dysplasia in Patient 5 shows a (A) dislocated left hip at age 0.45 years. Arthrogram shows (B) concentric closed reduction of the left hip at age 0.47 years, (C) early subluxation and valgus orientation of the right hip at age 2.64 years, and (D) progressive migration of both hips at age 3.16 years.

Fig. 2

Migration percentage of the right hip in patient 5 is shown to confirm progressive displacement.

Fig. 3

Migration percentage of the right hip of patient 13 is shown to show mild increase in migration % (see text).

Fig. 4A–G

Radiographic evidence charting acetabular dysplasia in patient 7 at (A) age 0.67 years shows the dislocation of the left hip. (B) At age 0.67 years, arthrogram confirms dislocation of the left hip. (C) Reduction of the left hip and early migration of the right hip is visible at age 1.34 years. (D) At age 1.97 years, there is progressive migration of the right hip. (E) Subluxation of the right hip is apparent at age 2.81 years. (F) At age 3.61 years the right hip is pictured following varus osteotomy, and (G) the left hip at age 9.76 years following varus osteotomy.

Fig. 5

The migration percentage of both hips of patient 7 is shown to show variable natural history (see Fig. 4).