Demographic differences in adolescent-diagnosed and adult-diagnosed acetabular dysplasia compared with infantile developmental dysplasia of the hip.

BACKGROUND

Acetabular dysplasia is a common cause of hip pain that can lead to premature osteoarthritis. This study explores whether demographic characteristics of patients diagnosed with acetabular dysplasia in adolescence and adulthood [adult-diagnosed dysplasia (AD)] differ from those who are diagnosed with developmental dysplasia of the hip (DDH) in infancy.

METHODS

Database review identified 633 patients undergoing periacetabular osteotomy for dysplasia from August 1991 to January 2008. Excluding patients with syndromal conditions and 80 lacking contact information, 421 patients received a questionnaire regarding birth and family history; 324 (70.3%) completed the survey. Thirteen were excluded because of unrelated hip conditions, leaving 311 patients for analysis.

RESULTS

Respondents were divided into 2 groups according to whether they had a history of DDH in infancy (102 patients) or were diagnosed in adolescence/adulthood (209 patients). Statistically significant differences (P < 0.05) were found in sex distribution (female: DDH = 98.0%, AD = 88.0%), affected limb (left hip: DDH = 33.3%, AD = 19.1%), bilaterality (DDH = 45.1%, AD = 61.2%), and breech presentation (DDH = 25.3%, AD = 9.4%). Over 50% of all the respondents had a family history of hip disease; over 40% were first-order relatives. First-order family members of patients with AD had a higher incidence of hip replacement by the age of 65 (50.0% vs. 22.7%). Patients with DDH were more likely to have first-order family members with DDH (59.0% vs. 15.8%).

CONCLUSIONS

This study confirms demographic differences between patients diagnosed with hip dysplasia in infancy versus adolescence/adulthood and supports the hypothesis that these represent distinct forms of dysplasia. In both, there is a familial tendency toward hip disease with a higher incidence of arthroplasty in the AD group's family members and higher frequency of infantile dysplasia in the DDH group's family members.

CLINICAL RELEVANCE: Infantile DDH is diagnosed with neonatal examination and patients are routinely followed into adolescence. Adolescent/adult AD is not detected until symptoms develop. Further study is needed to determine whether younger family members of patients with hip osteoarthritis should be screened to detect potentially at-risk hips.