Prostheses, Surgery, Conventional radiography, Musculoskeletal joint, Musculoskeletal bone
A. L. Proenca, A. P. Caetano, L. Bogalho; Lisbon/PT
THA is an orthopedic procedure in which the femoral head and cartilage of the acetabulum are surgically excised and replaced by prosthetic components.
With the increasingly older population,
hip replacement has become a common finding in daily medical practice.
The most common indication for THA is osteoarthritis,
but it can also be performed in trauma,
osteonecrosis or hip dysplasia.
The radiography has an important role in the evaluation of hip arthroplasty,
in postoperative assessment and follow-up.
Types of THA
Multiple designs and materials for THA are currently available and the surgeon´s selection is based on patient´s mobility and longevity,
bone quality and dimensions,
material availability and the surgeon´s experience.
Most modern THA systems are modular,
which means the femoral stem,
acetabular cup and liner are individual components,
allowing better size and fitting customizations.
The fixation techniques of the hip prosthesis include: cemented or non-cemented fixation.
In the cement fixation,
there is acrylic cement with additives.
In non-cemented fixation a press fitting mechanism (a slightly oversized component into a prepared cavity) is used and a porous coating allow bony ingrowth.
Screws can also be used to aid acetabular fixation.
There is a tendency to use preferably non-cemented THA in younger patients,
due to better long-term results,
as cemented components have a tendency to loosen over time.
Fig. 2: Cemented (A), non-cemented(B) and hybrid (C - cemented acetabular component and non-cemented femoral component) THA.
Fig. 3: Visible acetabular and femoral components in a femoral head dislocation.