Tomoyuki Nakamura, Toshio Kitano, Atsuhito Seki, Kousuke Iba, Kazuharu Takikawa, Keisuke Nakagawa, Tomonori Tetsunaga, Aya Narita, Kenichi Mishima, Yasuhiro Oikawa, Yuma Onishi, Masako Tsukanaka, Ryosuke Yamaguchi, Takuya Otani, Yutaka Inaba, Yasuharu Nakashima
The late diagnosis of DDH remains prevalent in Japan. Strengthening the implementation of the recommended screening/referral criteria may reduce delayed diagnoses. AVN was independently associated with the reduction method, underscoring the importance of early detection and appropriate treatment selection to minimize complications.
BACKGROUND: The Japanese Pediatric Orthopaedic Association (JPOA) established a nationwide registry for pediatric orthopaedic diseases in 2020. National-level data on late-diagnosed developmental dysplasia of the hip (DDH) and avascular necrosis (AVN) after treatment remain limited. This study aimed to evaluate the frequency of the late diagnosis of DDH, estimate the potential impact of the recommended screening/referral criteria, and identify factors associated with AVN using registry data.
METHODS: This retrospective observational study analyzed DDH patients registered between January 2020 and March 2025. A late diagnosis was defined as a diagnosis at ≥12 months of age. Among patients included in the B-registration with complete baseline data, 408 were analyzed for the late diagnosis of DDH. AVN was assessed according to the Salter criteria; 278 patients (305 hips) with available reduction and AVN data were included in the AVN analysis. Multivariable logistic regression was performed to identify independent factors associated with the late diagnosis of DDH and AVN.
RESULTS: Late diagnosis occurred in 60 of the 408 patients (14.7%). Referral by an orthopaedic surgeon was independently associated with the late diagnosis of DDH. Among the late-diagnosed patients, 19 (32%) had registry-recorded characteristics that would have met the recommended referral criteria. Under a hypothetical best-case assumption that all 19 patients would have been diagnosed before 12 months of age, the late-diagnosis rate would theoretically have decreased to approximately 10%. AVN occurred in 17 of the 305 hips (5.6%). Relative to Pavlik harness treatment, closed reduction (OR 3.58) and open reduction (OR 11.70) were independently associated with higher odds of AVN.
CONCLUSIONS: The late diagnosis of DDH remains prevalent in Japan. Strengthening the implementation of the recommended screening/referral criteria may reduce delayed diagnoses. AVN was independently associated with the reduction method, underscoring the importance of early detection and appropriate treatment selection to minimize complications.