Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

BACKGROUND AND PURPOSE: Adequate restoration of femoral offset (FO) is critical for successful outcome after hip arthroplasty or fixation of hip fracture. Previous studies have identified that hip rotation influences the projected femoral offset (FOP) on plain anteroposterior (AP) radiographs, but the precise effect of rotation is unknown. PATIENTS AND METHODS: We developed a novel method of assessing rotation-corrected femoral offset (FORC), tested its clinical application in 222 AP hip radiographs following proximal femoral nailing, and validated it in 25 cases with corresponding computed tomography (CT) scans. RESULTS: The mean FORC was 57 (29-93) mm, which differed significantly (p < 0.001) from the mean FOP 49 (22-65) mm and from the mean femoral offset determined by the standard method: 49 (23-66) mm. FORC correlated closely with femoral offset assessed by CT (FOCT); the Spearman correlation coefficient was 0.94 (95% CI: 0.88-0.97). The intraclass correlation coefficient for the assessment of FORC by AP hip radiographs correlating the repeated measurements of 1 observer and of 2 independent blinded observers was 1.0 and 1.0, respectively. INTERPRETATION: Hip rotation affects the FOP on plain AP radiographs of the hip in a predictable way and should be adequately accounted for.

Original publication




Journal article


Acta orthop

Publication Date





389 - 395


Arthrography, Arthroplasty, Replacement, Hip, Bone Nails, Femur, Hip Fractures, Hip Joint, Hip Prosthesis, Humans, Models, Biological, Observer Variation, Range of Motion, Articular, Recovery of Function, Reproducibility of Results, Rotation, Tomography, X-Ray Computed