Total hip arthroplasty in osteonecrosis secondary to sickle cell disease.

BACKGROUND: Sickle cell disease (SCD) is a multisystem disease, and the predominant articular manifestation is osteonecrosis (ON). Total hip arthroplasty (THA) is technically challenging, and the complication rates are high. In this retrospective study, we have analysed the outcome of THA in a cohort of patients with SCD at our institution. MATERIALS AND METHODS: We identified 34 THAs between 1999 and 2016 in 30 patients (mean age 37 years) from our SCD database. Co-morbidities, both sickle and non-sickle-related, were documented. Complications and indications for revision surgery were analysed. RESULTS: An uncemented prosthesis was predominantly used. The mean follow-up was 10.5 years (range 1-18). Six patients had revision surgery (17.6%), 2 (5.8%) for Prosthetic Joint Infection (PJI), and 4 (11.7%) for osteolysis of the acetabular component. CONCLUSION: Our revision rates were comparable to the published literature. Our combined sickle cell clinic and the coordinated multidisciplinary management have been successful in reducing morbidity.

Predicting the underestimation of the femoral offset in anteroposterior radiographs of the pelvis using 'lesser trochanter index': a 3D CT derived simulated radiographic analysis.

We developed 'lesser trochanter index' (LTI) and estimated its accuracy in predicting the underestimation of offset in the anteroposterior (AP) pelvic radiographs. We reconstructed 320 simulated radiographs from the CT scans of 40 adult hips at different rotational projections of 10° increments from 30° internal rotation to 40° external rotation. Underestimation of femoral offset as a percentage was derived from the neck profile angle for all radiographs. Radiographs with an LTI value above 35 were 94% (95% CI, 89%-97%) likely to underestimate femoral offset by more than 5%. Radiographs with LTI between 0 and 30 demonstrated femoral offset within 5% of the true offset (predictive value 100%, CI 87%-100%). LTI could be a useful guide in preoperative templating of hip arthroplasty.

The prevalence of cam-type femoroacetabular morphology in young adults and its effect on functional hip scores.

Pelvic computed tomography (CT) scans of forty five young adults were reviewed and the alpha angle was calculated. The patients were selected on the basis of an age of less than 40 years and the absence of any CT evidence of previous hip pathology. An alpha angle of >55º was considered positive for cam morphology. The non-arthritic hip score and the University of California Los Angeles activity score were completed by the selected group of patients. The mean age of the individuals was 33 years (range, 20 to 40). The mean alpha angle at the superoinferior position of the anterosuperior quadrant of the femoral neck was 50.1º on the right side and 49.6º on the left. The prevalence of cam morphology was found to be 20% in the right hip and 17.7% in the left hip. There was a relatively higher prevalence of cam morphology in men. We also compared the functional scores of patients with an alpha angle >55º and those with an alpha angle =55º. We found no statistically significant difference between the two groups for both scores.

Morphologic features of congenital acetabular dysplasia: one in six is retroverted.

It generally is thought that in congenital hip dysplasia, the opening of the acetabulum lies in excessive anteversion from the sagittal plane. Although this is true for the majority of patients, we found that one in six patients with acetabular dysplasia has retroversion in which the superior 1/3 of the acetabulum faces posterolaterally. Our method of analysis depends mainly on one true orthograde view of the pelvis. This view can be obtained easily and has the advantage of allowing the surgeon to adjust the correction during surgery. In the dysplastic hip with acetabular retroversion, realignment osteotomy still may be done but the corrective maneuvers are different.