Automated determination of the theoretical range of hip motion prior to total hip arthroplasty using 3D models created from pelvic CT scans

One of the major concerns following a total hip arthroplasty (THA) is the risk of dislocation: the artificial femoral head pops out of the replaced acetabulum due to a leverage effect. It affects about 4,000 patients a year in the UK, for 80,000 THA1. To prevent this complication, surgeons would benefit from estimating the range of angular hip motion that can be achieved by their patient without impingement between the femur and the pelvis. It would allow them to position more accurately the hip implant during the surgery. During the project, functional specifications have been established first and analysed before choosing a coherent solution. Then 2-D CT-scans of the hip have been converted to 3-D models with the Mimics software, which is specialised in DICOM (Digital Imaging and Communications in Medicine) data post-processing. The hip centre was measured by locating the centre of extrapolated spheres fitted on the acetabulum and femoral head. The 3D volume models generated were then decomposed into several surface files and exported to the Solidworks software, then reunited into two bone surface structures. The pelvic part being fixed, the femur has been added and located in anatomical position. The motion study manager of Solidworks was then used to set a motion analysis until impingements occurred in different directions. The angular position of the femur at impingement times was measured using the femoral neck axis and the anatomical planes (sagittal, coronal and transverse) centred on the hip joint centre. Then the range of motion in those planes was then deducted. The types of impingements that occurred during simulation are consistent with clinical findings about dislocation. Therefore the simulation was accurate and should be developed in order to explore more paths like projecting the different femoral angles on radiological planes.

Name dc:type.qualificationname

msc

Level dc:type.qualificationlevel

masters-pg

Grantor dc:publisher.institution

University of Strathclyde

Year dc:date.issued

2015

Author dc:creator

• Walter, Ségolène

Advisor dc:contributor.advisor

• Deakin, Angela

DOI

10.48730/yynt-mb42

Identifier

T14214

Author Identifier

201491368

OAI identifier oai:identifier

oai:strathclyde:kh04dp702