Bone turnover markers (osteocalcin, bone-ALP, beta-crosslaps--CTX) and cytokines (IL-1 alpha, IL-8 and IL-10) in hip joint fluid were analyzed in patients with aseptic loosening of prosthesis before revision surgery, in patients with rheumatoid arthritis and with idiopathic coxarthrosis for comparison.
Bone turnover markers were determined by electrochemiluminescence, colorimetric or ELISA method and cytokines by ELISA in joint fluid collected at the beginning of the surgery.
Patients with loose implants had lower concentration of the resorption marker than cases with rheumatoid arthritis and coxarthrosis (7771 +/- 3322 vs 25986 +/- 16059 p < 0.01 and 23047 +/- 32556 pmol/L, p < 0.003) and over tenfold lower concentration of osteocalcin, the bone formation marker (p < 0.04 i p < 0.01). Concentration of IL-8 was elevated and similar in patients with loosening and rheumatoid arthritis while in cases with osteoarthrosis the mean value was twice lower. The anti-inflammatory IL-10 was highly elevated only in cases with prosthesis loosening. Additionally, a negative correlation was observed between CTX and IL-10 was and positive between IL-10 and time to revision surgery.
We conclude that increased local production of inflammatory cytokines leading to uncoupling of bone turnover is a part of the loosening process.