This article is more than 5 years old. Information may no longer be current.
CT reveals reduced wear and osteolytic lesions with highly crosslinked PE in THA
Researchers had concerns with highly crosslinked polyethylene in total hip arthroplasty in long-term use.
Click Here to Manage Email Alerts
An investigational study showed the use of highly crosslinked polyethylene in total hip arthroplasty exhibited less wear compared to conventional polyethylene, but it revealed this type of hip articulation can lead to periacetabular osteolytic lesions at a minimum 7-year follow up, according to a presenter.
“We have identified osteolytic lesions in hips with highly crosslinked polyethylene [HXLPE] at 7 [years] to 10 years after prior total hip arthroplasty. The incidence and volumes of lesions were similar to those observed in the small studies at 5 [years] to 6 years. The osteolytic lesions were usually small, but clearly they were present,” Donald Howie, MD, PhD, of Adelaide, Australia, said. “They were seen in the absence of significant wear and the incidence was similar in the 36- and 28-mm articulation.”
The aim of the randomized controlled trial was to determine the frequency and volume of periacetabular osteolysis at a minimum of 7 years following primary total hip arthroplasty (THA). It compared the results of THA in patients who received standard and large-size cobalt chrome femoral heads and HXLPE acetabular liners.
The polyethylene liners underwent 10 Mrad electron beam irradiation, and was then melted and sterilized with gas plasma.
The study included 122 patients of which 69 patients had 28-mm articulations and 53 patients had 36-mm articulations. The patients’ median age at THA was 72 years. There were 71 women and 51 men.
Patients were randomized intraoperatively to determine the size of the articulation they would receive.
An examination of the hip with quantitative CT to detect osteolysis revealed radiolucent lesions in 29 hips (24%). Investigators excluded 10 hips from the study due to inadequate radiographs early in the follow-up and they excluded 11 other hips because they had pre-existing acetabular cysts.
“We concluded, and we are confident, that we felt that eight radiolucent lesions with no preexisting cysts indicated osteolysis. If you look at the osteolytic lesions of the eight of 101 hips, the median age of the patients was 73 [years]. It was an older age group,” Howie said.
All of the lesions, he said, were adjacent to the acetabular component and located in the ilium adjacent to either fixation screws or empty screw holes.
“We did not see any femoral osteolysis,” Howie said.
The lesions were about 1.7 cm3 in size, and Howie described them as fairly small but still present.
The investigators noted in the study that additional monitoring of the osteolytic lesions should be done to determine if they become any larger or more clinically relevant.
According to Howie, this was one of the largest studies to use CT to identify osteolysis. However, the study limitations were the small sample size and the older age of the patients, he said. – by Robert Linnehan
- Reference:
- Howie D. Paper #253. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting; March 11-15, 2014. New Orleans.
- For more information:
- Donald Howie, MD, PhD, can be reached at the Department of Orthopaedics and Trauma, Royal Adelaide Hospital, North Terrace, Adelaide SA 5000, Australia; email: donald.howie@health.sa.gov.au.
Disclosure: Howie receives research or institutional support as a principal investigator from Zimmer.