Assessment of inducible fracture micromotion in distal radial fractures using radiostereometry.

Objectives: This study examined the potential for measuring dynamic inducible micromotion (DIMM) between fragments in healing distal radial fractures using radiostereometry (RSA).

Design: Prospective imaging study.

Setting: University teaching hospital.

Impact of trochanteric heterotopic ossification on measurement of femoral bone density following cemented total hip replacement.

During a study of bone mineral density changes around cemented femoral implants, we recognized heterotopic ossification occurring regularly in a position anterior to the greater trochanter and proximal femur. The aim of this study was to describe the incidence, distribution, and effect of this ossification on periprosthetic DXA scans following primary cemented total hip replacement. One hundred eleven patients underwent postoperative DXA examinations measuring changes in bone mineral density with heterotopic ossification identified and localized on standard radiographs with confirmation using DXA subtraction imaging.

A hydroxyapatite graft substitute reduces subsidence in a femoral impaction grafting model.

Synthetic bone graft substitutes have been developed for impaction grafting revision hip surgery in response to concerns about the availability and potential infection risk of allograft. We performed an in vitro experiment to determine whether a synthetic porous hydroxyapatite material might improve resistance to cumulative subsidence and cyclic (elastic) movement on loading. We impacted different ratios of hydroxyapatite and allograft (0%, 50%, 70%, and 90% hydroxyapatite) into composite femoral models (eight per group) and implanted tapered, polished stems with cement.

The correlation between immediate radiolucent lines and early implant migration in cemented acetabular components.

Periacetabular radiolucent lines (RLLs) on postoperative radiographs have been associated with early loosening of the acetabular component. It has also been shown that excessive migration of an implant corresponds to an increased incidence of later clinical failure. This study relates RLLs on anterior-posterior hip radiographs taken 10 days and 6 months postoperatively to implant migration detected by roentgen stereophotogrammetric analysis.

Insertion of tantalum beads in RSA of the hip: variations in incidence of extra-osseous beads with insertion site.

Radiostereometric analysis (RSA) is a technique that can be used to measure the in-vivo micro-motion of the components of hip arthroplasty. It requires the insertion of tantalum beads into the bone permitting analysis of the radiographs. Extra-osseous beads reduce the usable bead pattern and previous studies have reported their incidence in the proximal femur as between 11% and 13% of all inserted beads.