Hip dysplasia

Clin Orthop Relat Res (2008) 466:871–877 DOI 10.1007/s11999-008-0118-6

S Y M P O S I U M : D E V E L O P M E NT A L D Y S P L A S I A O F T H E H I P

Developmental Dysplasia of the Hip and Occult Neurologic Disorders
A. Z. Luther, N. M. P. Clarke MB ChB, ChM FRCS

Published online: 30 January 2008 Ó The Association of Bone and Joint Surgeons 2008

Abstract Developmental dysplasia ofthe 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 thissuggestion 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 560patients 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.

Introduction Developmental dysplasia of thehip (DDH), previously known as congenital dislocation of the hip (CDH), is a common and well-documented condition primarily detected in neonates. The principal abnormality is hip instability affecting both acetabular and femoral development [19]. It is a spectrum of disease, ranging from the unstable hip, where the femoral head is well centered, but which displaces when force is applied, to thefully fixed dislocated hip [1]. DDH has a complex etiology, although research suggests it is more prevalent among first children, girls, those with a positive family history, and infants who were breech presentation [5, 21, 22, 24]. DDH in the UK is screened for neonatally using the Ortolani and Barlow tests, although ultrasound has proved a useful secondary tool [2, 5, 8, 23]. Early diagnosis allowsusually successful treatment in a Pavlik harness. If this is unsuccessful or the diagnosis made late surgical treatment is necessary [5, 20]. The displacement and dislocation of the hip is also a recognized sequela of neuromuscular conditions such as cerebral palsy and myelomeningocele. This is considered an entirely different clinical entity to DDH, due to the differing underlying pathology andconsequently differing expected outcomes. Dysplastic changes occur as a result of altered muscle tone, which causes abnormal stresses across the hip joint. This will gradually affect the positioning of the femoral head, subsequently impairing acetabular development [7, 11, 13, 17]. Consequently, neuromuscular dysplasia of the hip (NDH) generally presents later in childhood than DDH [14]. Treatmentis primarily surgical, and patients may require multiple operations due to the underlying problem of disordered muscle tone [13, 17].

Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. Each author certifies thathis or her institution has approved or waived approval for the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research. A. Z. Luther, N. M. P. Clarke (&) MP 817, Southampton General Hospital, University of Southampton, Tremona Road, Southampton SO16 6YD, UK e-mail: ortho@soton.ac.uk

123

872

Luther and Clarke...