Metal-on-polyethylene hip implant may improve resurfacing arthroplasty outcomes
Researchers are working on an off-the-shelf version of the prosthesis to benefit more patients.
Use of a metal-on-highly crosslinked polyethylene implant in hip resurfacing arthroplasty may provide successful short-term outcomes and be a viable option for suitable patients who currently lack a hip resurfacing arthroplasty option, according to published results.
“This is a preliminary report of custom devices, but we have had the largest global experience of successful hip resurfacings,” Ronan B.C. Treacy, MB, ChB, FRCS(Orth), of The Royal Orthopaedic Hospital in Birmingham, United Kingdom, told Orthopedics Today. “Particularly in smaller patients and female patients, under current guidelines, they are excluded from the benefits of resurfacing with historical bearings and this gives us an insight into the future on showing that a hard-on-soft bearing may, in fact, be viable for the use in these patients.”
Treacy and his colleagues assessed clinical outcomes, radiological outcomes, Oxford Hip Scores and implant survivorship among 84 patients (88 hips) who underwent hip resurfacing arthroplasty with a custom metal-on-monobloc highly crosslinked polyethylene implant (Jointmedica). Overall, 85 hips underwent primary resurfacing. Three hips underwent revision of previous metal-on-metal hip resurfacing arthroplasty with the custom implant.
Results showed an increase in median Oxford Hip Scores from 24 preoperatively to 48 at the latest follow-up. One patient had head-neck junction lucency, according to the radiographic findings. However, researchers found no other radiolucencies, osteolysis, component migration or femoral neck thinning.
“Since we were not using metal-on-metal bearings, there were no metal ions reported, which is a step forward,” Treacy said. “The functional results were the same with this device as we have previously reported with Birmingham Hip Resurfacing (Smith & Nephew).”
Despite these promising, early outcomes, Treacy noted longer-term follow-up is needed to confirm the results. Researchers are working on an off-the-shelf hip resurfacing arthroplasty device in multiple sizes that would benefit more patients, he said.
“It is just the early days, and these are custom devices,” Treacy said. “Ideally, we would like to fulfill the regulatory requirements so that we can move on to having an off-the-shelf device available.”
- Treacy RBC, et al. Bone Joint Res. 2019;doi:10.1302/2046-3758.810.BJR-2019-0060.R1.
- For more information:
- Ronan B.C. Treacy, MB, ChB, FRCS(Orth), can be reached at Royal Orthopaedic Hospital NHS Foundation Trust, Bristol Road South, Northfield, Birmingham B31 2AP, United Kingdom; email: firstname.lastname@example.org.