Current Concepts in Acetabular Positioning in Total Hip Arthroplasty

Abstract

Being one of the most successful surgeries in the history of medicine, the indications for total hip arthroplasty have widened and are increasingly being offered to younger and fitter patients. This has also led to high expectations for longevity and outcomes. Acetabular cup position has a significant impact on the results of hip arthroplasty as it affects dislocation, abductor muscle strength, gait, limb lengths, impingement, noise generation, range of motion (ROM), wear, loosening, and cup failure. The variables in cup position are depth, height, and angular position (anteversion and inclination). The implications of change in depth of center of rotation (COR) are medialized versus anatomical positioning. As opposed to traditional medialization with beneficial effects on joint reaction force, the advantages of an anatomical position are increasingly recognized. The maintained acetabular offset offers advantages in terms of ROM, impingement, cortical rim press fit, and maintaining medial bone stock. The height of COR influences muscle activity and limb lengths and available bone stock for cup support. On the other hand, ideal angular position remains a matter of much debate and reliably achieving a target angular position remains elusive. This is not helped by variations in the way we describe angular position, with operative, radiologic, or anatomic definitions being used variably to describe anteversion and inclination. Furthermore, pelvic tilt plays a major role in functional positions of the acetabulum. In addition, commonly used techniques of positioning often do not inform us of the real orientation of the pelvis on operating table, with possibility of significant adduction, flexion, and external rotation of the pelvis being possibilities. This review article brings together the evidence on cup positioning and aims to provide a systematic and pragmatic approach in achieving the best position in individual cases.

Ceramic-on-ceramic vs ceramic-on-polyethylene, a comparative study with 10-year follow-up

“…Our study showed that a higher inclination angle of the cup is a significant risk factor for wear. The same results are seen in the literature, with inclination angles above 45 degrees[ 26 - 28 ]. Since the mean angle of CoPE in our group was above this angle, it supports that acetabular positioning is highly important to reduce wear of CoPE.…”

Finite Element Analysis of Different Hip Implant Designs along with Femur under Static Loading Conditions

“…The complete hip implant which is modeled with different cross-sections of stems, it is inserted into the femur bone. These implants are positioned into the bisected femur bone considering the patient’s femur and pelvic anatomy [28]. These hip implants along with femur are used for the static structural analysis in ANSYS R-19 to evaluate the best implant design out of the developed four different models.…”

Adverse Reaction to Zirconia in a Modern Total Hip Arthroplasty with Ceramic Head

“…Although ceramics have been described as biologically inert, sufficiently small enough particulates of zirconia, if released, may produce an immune reaction similar to those seen with polymers and metal debris [ 34 , 35 ]. Zirconia hypersensitivity and ALTR due to wear debris are multifactorial; however, we will describe what we believe to be the likely etiology in our case in the following paragraph [ 3 , 8 , 32 , 33 , 40 , [42] , [43] , [44] , [45] , [46] , [47] ].…”