Objective: 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.
Methods: 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.
Results: 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.
Conclusions: We conclude that increased local production of inflammatory cytokines leading to uncoupling of bone turnover is a part of the loosening process.