Use of computed tomography in the evaluation of osteointegration and bone remodelling around cementless revision oval cup - type TC
Abstract
Introduction: The main goal of our work is to describe the general principles of solving a defective acetabulum using oval revision cup - type TC, evaluation of its osteointegration and remodelling of a transplanted bone tissue using digital radiography (x-ray) and modified computed tomography (CT) to eliminate the artefacts around metallic implants. Methods and materials: TC cup is based on a spherical cup - type SF that is formed into an oval shape with four prominent ribs (12mm and 18mm).
Perioperatively, the bone defects below the implant and the spaces between the ribs are filled with bone graft. We evaluated 20 patients who signed informed consent with CT scan.
Average follow-up was at 9.1 years. According to x-ray images we evaluated the osteointegration and the implant position, with the CT scan we evaluated the bone remodelling after the reduction of artefacts (Aquilion 64 - Toshiba Medical Systems).
The functional evaluation was based on a questionnaire according to Harris (HHS). Results: According to radiological evaluation, osteointegration of the revision cup was good in 16 cases, in 4 cases we found radiolucent line up to 2mm in zone III according to De Lee and in 1 case we recorded an interruption of both proximal screws without evidence of implant migration.
With the help of the CT scan in all cases we detected bone implant remodelling between the ribs space of the implant and bone defects after spongioplasty were always healed. Periacetabular osteolysis was not detected in the x-rays.
In 4 patients we confirmed an ingrowth of fibrous tissue (in a width of 2mm in the convexity) with a stable cup. The average Harris hip score increased from a preoperative value of 42.1 points to 82.3.