The Occurrence of Occult Acetabular Dysplasia in Relatives of Individuals With Developmental Dysplasia of the Hip.

BACKGROUND: This study sought to determine the hip pathology of family members of patients with developmental dysplasia of the hip (DDH). The authors evaluated 120 people from 19 families known to have at least 1 member with surgically treated DDH. Each individual's functional outcome scores and pelvic radiographs were assessed for hip symptoms or pathology. METHODS: Using a genetic population database and a pediatric hospital patient population, 19 families with high rates of DDH were identified. All family members (n=120) underwent physical examination, radiographic assessment, and completion of outcome instruments [American Academy of Orthopedics (AAOS) Hip and Knee; Harris Hip Score (HHS); and Western Ontario and McMaster Universities Arthritis Index (WOMAC)]. RESULTS: The 120 subjects ranged from 1 to 84 years, 34 had orthopaedically treated DDH. Of the remaining 86 supposedly normal subjects, 23 (27%) had occult acetabular dysplasia (OAD) as defined by center edge angle (CEA) <20 and/or a Severin score of III or greater. Sixty percent of the 86 individuals were less than 30 years old, 74% of the OAD group were less than 30. Outcome scores of the treated DDH patients (AAOS, HHS, and WOMAC) were worse on the involved side regardless of age. Over age 30 individuals with OAD had statistically significant decreases in their AAOS Hip and Knee and WOMAC scores on the dysplastic side, but their HHS scores were not significantly different. CONCLUSIONS: Twenty-seven percent of first-degree and second-degree relatives of patients with DDH had unsuspected radiographic acetabular dysplasia in our study. Most of the subjects with OAD were younger than 30. After age 30, many of these patients developed symptoms. CLINICAL RELEVANCE: In families with a significant history of DDH, radiographic screening of siblings of patients with DDH to define OAD may be prudent. LEVEL OF EVIDENCE: Level I­diagnostic study.

Total hip arthroplasty, hip osteoarthritis, total knee arthroplasty, and knee osteoarthritis in patients with developmental dysplasia of the hip and their family members: a kinship analysis report.

BACKGROUND: Developmental dysplasia of the hip (DDH) is a familial condition with a wide phenotypic expression. Families with high rates of DDH may have individuals with subtle phenotypic expression that can progress to osteoarthritis and require total hip arthroplasty (THA). This study compares the rates of THA in relatives of individuals with DDH with individuals in control families. METHODS: Probands with a diagnosis of DDH were identified using medical records linked to the Utah Population Database. Ten age-matched and sex-matched controls were randomly selected from a pool of unaffected individuals within the Utah Population Database. Diagnostic and procedural codes were used to determine the incidence of hip and knee osteoarthritis (HOA and KOA) and of THA and total knee arthroplasty (TKA) among the cases and controls and their relatives. Relative risks (RR) for HOA and KOA and for THA and TKA were calculated for the probands/controls and their family members. RESULTS: The RR of HOA was significantly increased in probands (RR=82.4; P<2e-16), their parents (R=2.22; P=0.0003), and in their grandparents (RR=1.33; P=0.011). The RR of THA was also significantly increased in probands (RR=1168; P <3e-08) and in their grandparents (RR=2.06; P=0.01). The RR of KOA was significantly increased in probands with a diagnosis of DDH (RR=20.96; P=2.2e-8) but not in their parents or grandparents. The RR of TKA was also increased in probands alone (RR=57.47; P=1.7e-05). CONCLUSIONS: Parents and grandparents of individuals with diagnosed DDH are significantly more likely to be diagnosed with HOA and undergo THA than members of the general population. These first-degree and second-degree relatives were not at higher risk for KOA or TKA. Given the known familial association of DDH, this association with osteoarthritis of the hip suggests a risk of undiagnosed hip dysplasia in individuals whose families have a high rate of DDH. LEVEL OF EVIDENCE: Level III.