Introduction:
Aseptic loosening is the leading cause of implant failure. Aseptic loosening is the
result of different mechanisms leading to increased periprosthetic bone resorption.
Therefore, measuring biochemical bone markers can be an approach to identify early
resorption and implant loosening We hypothesized that TRAP 5b is a sensitive marker
for periprosthetic bone turnover and a possible predictor of aseptic loosening.
Methods:
A rat model of aseptic loosening with continuous infusion of polyethylene particles
was used. Given the fact that many patients undergoing total joint replacement and
developing aseptic loosening suffer from osteoporosis, the rats were ovariectomized
12 weeks before the experimental procedures to induce poor bone quality and include
the influence of osteoporosis on the loosening process. 60 ovx rats were used and
randomized into the different experimental groups. Blood samples were drawn 12, 6
and 1 weeks before the surgery and on Post Operative Day 0, 7, 14, 28, 35, and 42
The serum was analyzed by ELISA for Osteocalcin, PINP, CTX concentrations and TRAP
5b activity. To verify the result of ovariectomy, bone mineral density was measured
by DEXA.
Results:
Results for TRAP 5b: Postoperatively, the maximum was reached on day 7 and TRAP 5b
activity decreased slowly until day 42. Similar, in the sham group maximum was reached
on day 7 and it decreased slowly until day 42. On every day, TRAP 5b activity in the
prostheses group was significantly higher than TRAP 5b activity in the sham-operated
group
Discussion:
Our investigation showed for TRAP 5b, a high activity levels as an indication for
an increased periprosthetic bone resorption leading to aseptic loosening. TRAP 5b
is eligible for the early diagnosis of aseptic loosening.
