Three‐Dimensional Estimation of the Femoral Head Center From Trochanteric Landmarks in Japanese Female Patients With Developmental Dysplasia of the Hip
Norio Imai, Atsushi Sakagami, Daisuke Homma, Yuki Komuta, Yuki Hirano, Yoji Horigome, Hiroyuki KawashimaABSTRACT
Introduction
Although pelvic landmarks have traditionally been used to estimate the femoral head center (FC), their reliability may be limited in patients with developmental dysplasia of the hip (DDH). In contrast, femoral‐based reference methods have been insufficiently investigated. This study aimed to evaluate the feasibility and clinical utility of estimating the FC location in DDH using a three‐dimensional model derived from trochanteric landmarks.
Methods
We retrospectively analyzed 128 femurs from 84 female patients with DDH (mean age, 36.9 years) who underwent curved periacetabular osteotomy (CPO) from April 1, 2010, to September 30, 2020, and had no symptoms involving the spine or knee. The FC was estimated using multiple regression models based on the three‐dimensional coordinates ( x , y , and z ) of the greater and lesser trochanter tips. Differences between the estimated and actual FC positions were assessed along all three axes.
Results
Correlation coefficients between the estimated and actual FC ranged from 0.725 to 0.875 across the three directions. The mean absolute error was 2–3 mm, with greater errors observed in the anteroposterior direction than in the craniocaudal direction. An estimation error within 3 mm may be considered relatively small in the context of clinically acceptable ranges reported in previous studies for restoring femoral offset and leg length during total hip arthroplasty (THA), supporting the practical applicability of this method in preoperative planning.
Conclusion
The accuracy of the present approach was comparable to that reported in healthy populations and exceeded that of previous pelvic landmark‐based regression techniques. This trochanter‐based three‐dimensional method enables clinically acceptable estimation of the FC in patients with DDH and may serve as a useful adjunct for planning of the femoral component when the native FC is difficult to identify.