Metal Üzeri Metal Kalça Artroplastilerinde Serum ve İdrar Metal İyon Düzeylerinin Değerlendirilmesi

Abstract

In total hip arthroplasty (THA), most important failure mechanism is the poliethylene debris leading to osteolysis and aseptic loosening. With the use of metal-on-metal (MOM) prosthesis, emerging wear debris is much lower than wear debris of conventional polyethylene-on-metal THA. Eventually, MOM prosthesis gained popularity in active patients. However, in midto long-term follow-ups, metal ion levels (cobalt, chromium, molybdenium) seem to be elevated in serum and urine. Improved tribologic design provides significant decrease in wear rates. In MOM arthroplasty, to provide effective fluid lubrication mode, there must be larger head diameter, lower clearance and better sphericity. Prosthesis with lower clearance and larger heads have lower volumetric wear. Metal ions, released from metal wear debris, may lead to local and systemic effects in tissues such as delayed type hypersensitivity, metallosis, ALVAL, osteolysis, DNA toxicity, lymphopenia, carcinogenicity and these situations should be concerned. Aims of this study were to compare metal ion levels in patients? serum and urine according to the articulation type and implant characteristics, to detect MOM implant toxicity and to give an idea for the latter studies. In this study, 3 groups (total patient count=68) are formed as patients with hip surface replacement, patients with MOM THA and patients with bilateral MOM prosthesis. A control group was consisted of age-matched healthy individuals (n=10). By using ICP-MS, analysis of the patients? serum and urine metal ion levels were evaluated. Also evaluations of lymphocyte count, creatinin, Harris Hip Score, etiologies of revisions were done. Statistical analysis was done by using Shapiro Wilk test, Kruskal Wallis test and Mann Whitney U test. Serum metal ion levels were higher in the surface replacement group (median sCr=1,99ppb, sCo=1,50ppb, sMo=0,29ppb) than total hip arthroplasty group (median sCr=1,73ppb, sCo=0,95ppb, sMo=0,16ppb). But urine metal ion levels were detected higher in the total hip replacement group (median uCr=2,18ppb, uCo=6,22ppb, uMo=19,92ppb) than the surface replacement group (median uCr=2,01ppb, uCo=4,74ppb, uMo=16,87ppb). The correlation between larger diameter and metal ion levels, was measured as statictically insignificant. But increasing metal ion levels were correlated with revision, and this was statistically significant. Higher values of metal ion levels could predict early implant failure and indicate revisions before marked clinical deterioration. To better understand diagnostic value of metal ion levels, there should be studies with large numbers of patients.