Retrospective cohort study following the contralateral hip in 286 patients who underwent THR for dysplastic OA. Compares 74 hips that developed advanced OA against 43 hips that reached age 65 without severe disease. Goal: define which AP pelvis radiographic parameters predict OA progression in untreated adult hip dysplasia.
Before this paper, the decision to operate on a young adult with mild-to-moderate dysplasia rested on clinical judgment with no agreed radiographic cutoffs — surgeons knew severe dysplasia was dangerous but lacked objective thresholds to act on borderline cases.
When you see a young adult with hip pain and residual dysplasia, apply these five AP pelvis thresholds: CEA <16°, extrusion index >31%, D/W ratio <38%, weight-bearing zone index >15°, or zero peak-to-edge distance. Any one of these findings places the patient in the group with near-certain OA progression. The argument for periacetabular osteotomy rather than observation becomes compelling.
Critically, do not stop at the AP view. A nearly normal AP pelvis can hide anterior subluxation; the false-profile is required to assess anterior coverage before you tell a patient their hip looks acceptable.
Retrospective cohort study following the contralateral hip in 286 patients who underwent THR for dysplastic OA. Compares 74 hips that developed advanced OA against 43 hips that reached age 65 without severe disease. Goal: define which AP pelvis radiographic parameters predict OA progression in untreated adult hip dysplasia.
Before this paper, the decision to operate on a young adult with mild-to-moderate dysplasia rested on clinical judgment with no agreed radiographic cutoffs — surgeons knew severe dysplasia was dangerous but lacked objective thresholds to act on borderline cases.
When you see a young adult with hip pain and residual dysplasia, apply these five AP pelvis thresholds: CEA <16°, extrusion index >31%, D/W ratio <38%, weight-bearing zone index >15°, or zero peak-to-edge distance. Any one of these findings places the patient in the group with near-certain OA progression. The argument for periacetabular osteotomy rather than observation becomes compelling.
Critically, do not stop at the AP view. A nearly normal AP pelvis can hide anterior subluxation; the false-profile is required to assess anterior coverage before you tell a patient their hip looks acceptable.