Positioning of the acetabular component in total hip arthroplasty has profound effects on the biomechanics, stability and wear of the prosthesis. Normal anatomical position in females is 57 degrees (50 – 67 degrees) inclination with 19 degrees (9 – 32 degrees) of anteversion, whilst in males 56 degrees of inclination (48 – 66 degrees) with 19 degrees (9 – 32 degrees) is normal. In total hip arthroplasty, inclination recommendation ranges from 30 – 50 degrees. The aim of this study was to radiographically measure acetabular component position in total hip arthroplasty and compare to normal values. The Widmer method was used by two independent observers to radiographically measure inclination in 522 patients using standard AP radiographs. Primary measures and variables were statistically analysed as was inter and intra observer reliability. All patients included within the study received total hip arthroplasty for age related degenerative changes to the hip. Operations were undertaken by 17 separate consultants or senior registrars under their care.Background
Method