Femoral offset is underestimated on anteroposterior radiographs of the pelvis but accurately assessed on anteroposterior radiographs of the hip.
ABSTRACT The aim of this retrospective cohort study was to identify any difference in femoral offset as measured on pre-operative anteroposterior (AP) radiographs of the pelvis, AP radiographs of the hip and corresponding CT scans in a consecutive series of 100 patients with primary end-stage osteoarthritis of the hip (43 men and 57 women with a mean age of 61 years (45 to 74) and a mean body mass index of 28 kg/m(2) (20 to 45)). Patients were positioned according to a standardised protocol to achieve reproducible projection and all images were calibrated. Inter- and intra-observer reliability was evaluated and agreement between methods was assessed using Bland-Altman plots. In the entire cohort, the mean femoral offset was 39.0 mm (95% confidence interval (CI) 37.4 to 40.6) on radiographs of the pelvis, 44.0 mm (95% CI 42.4 to 45.6) on radiographs of the hip and 44.7 mm (95% CI 43.5 to 45.9) on CT scans. AP radiographs of the pelvis underestimated femoral offset by 13% when compared with CT (p < 0.001). No difference in mean femoral offset was seen between AP radiographs of the hip and CT (p = 0.191). Our results suggest that femoral offset is significantly underestimated on AP radiographs of the pelvis but can be reliably and accurately assessed on AP radiographs of the hip in patients with primary end-stage hip osteoarthritis. We, therefore, recommend that additional AP radiographs of the hip are obtained routinely for the pre-operative assessment of femoral offset when templating before total hip replacement.
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ABSTRACT: 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.Acta Orthopaedica 06/2014; · 2.45 Impact Factor
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ABSTRACT: Lateral patellar arthritis has been associated with poor outcomes in unicompartmental knee arthroplasty. The current study correlates intraoperative findings with MRI imaging, skyline radiographs and the presence of anterior knee pain.The Knee 05/2014; · 1.70 Impact Factor
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ABSTRACT: The aim of this prospective study was to determine the clinical value of lateral radiographs and corresponding MRI scans in the preoperative evaluation of the functional integrity of the anterior cruciate ligament (ACL) in a consecutive series of 78 patients (93 knees) with medial compartment osteoarthritis. All knees received standardised radiographs and MRI imagery. The wear pattern on the lateral radiograph was described based on a modified Keyes classification. On MRI, the ACL and the percentage of intact posterior cartilage in relation to the anteroposterior tibia width were assessed. The MRI showed an intact ACL in 23 (25 %) knees, evidence of ACL degeneration in 54 (58 %) knees and a complete ACL tear in 16 (17 %) knees. All knees with an intact ACL showed ≥14 % intact posterior cartilage on sagittal MRI scans, except for one knee. All knees with a torn ACL demonstrated <14 % intact posterior cartilage. Of the 54 knees with evidence of ACL degeneration, eight knees had <14 % intact posterior cartilage similar to the wear pattern present in knees with torn ACLs. Out of the 24 knees with a torn or degenerated ACL and <14 % intact posterior cartilage on MRI, 23 (96 %) knees demonstrated posterior bony erosion on corresponding lateral radiographs. The assessment of intact posterior tibial cartilage on MRI and lateral radiographs helps to identify knees with functional ACL insufficiency. MRI with assessment of both the ACL morphology and the underlying tibial wear pattern appears to provide additional clinical benefit in cases in which the extent of posterior bony erosion on the lateral radiograph cannot be assessed with confidence. Diagnostic study, Level II.Knee Surgery Sports Traumatology Arthroscopy 04/2014; · 2.68 Impact Factor