The morphological variation of acetabular defects in revision total hip arthroplasty—A statistical shape modeling approach

Abstract

Classification and evaluation of acetabular defects remain challenging and are primarily based on qualitative classification methods. That is because quantitative techniques describing variations of acetabular defects and accompanying bone loss volume are not available. This study introduces a new method based on statistical shape models (SSMs) to quantitively describe acetabular defects. This method is then applied to 87 acetabular defects to objectively describe the variations in acetabular defects typically encountered during revision total hip arthroplasty. The absolute bone loss volume, relative bone loss volume, and relative bone loss surface area with respect to the SSM-based pre-diseased anatomy were used to quantify the acetabular bone defects in different segments of the acetabular surface. The absolute bone loss volume of the average defect shape was equal to 37.0 cm 3 . The first three principal modes, accounting for 62% of the total shape variation, were found to represent variations in acetabular defect morphology. The first, second, and third principal modes described, respectively, the size of the bone defects, the difference between superomedially and superolaterally migrated defects, and the degree of involvement of the posterior or anterior column. The developed SSM and the introduced approach could be used to create automated and unbiased classification methods based on quantitative data. Moreover, the proposed model and the underlying data provide the basis for a quantitative design approach where the shape and size of new acetabular implants are determined according to clinical variation present in acetabular defects.

Statistical Shape and Appearance Models: Development Towards Improved Osteoporosis Care

“…, where K is number of the most significant PCs used and N is the number of all PCs. The ratio describes how well the first a few principal components describe the total variation in the data set [16,47]. The generalization error is usually calculated with leave-one-out, and it measures how accurately SSAM can generate the specimen dropped out from the model as…”

“…Most studies [45,47,48] are based on generating a SSAM from healthy pelvic anatomies and then fit the SSAM to the patient's anatomy to quantify the severity of the acetabular defects, thus assisting in preoperative planning. Common to these studies is the limitation that they require manual segmentation of the target pelvis as well as identification/ labeling of the pathological areas.…”

Early clinical and radiological outcomes of the new porous titanium shell in combination with locking screw in revision total hip arthroplasty

“…Extensive bone loss and poor bone quality are two key challenges often encountered in revision total hip arthroplasty (THA) [ 1 ]. The goal of acetabular reconstruction is to achieve a long-lasting fixation, re-establish the center of rotation of the hip and provide a stable joint in a manner that deals minimal harm to the patient [ 2 ].…”

Study of Morphometric Analysis of Acetabulum and its Clinical Correlation

“…In clinical practice, acetabular prosthesis is constructed using morphometry of the acetabular fossa as reference data. Acetabular parameter is a diagnostic tool used by orthopedic surgeons in the course of surgical therapy (4,8) . For acetabular retroversion, some have postulated that the posterior acetabular wall is hypoplastic.…”