The Influence of Bone Cement Implantation in Primary Hip Arthroplasty on S100B Protein Serum Concentration and Patients' Cognitive Functions as Markers of Brain Damage.

Objective: The objective of the study was to evaluate the influence of the bone cement used during primary hip arthroplasty on brain functions assessed at the biochemical and clinical levels. The S100B protein is a biochemical marker of brain damage. Its plasma concentration was compared with the results of neuropsychological tests, conducted during the perioperative period.

Patients And Methods: Two groups of patients who underwent primary hip arthroplasty were analyzed; group one (n = 30) with the use of bone cement (cemented), group two (n = 30) without (cementless). All of the procedures were under spinal anesthesia with intravenous sedation. In each group, S100B protein concentration was examined before the surgery and just after the operation, and 6, 24, and 72 h after the procedure. Two neuropsychological tests were conducted before the surgery and 24 and 72 h after. The patients with preexisting blood flow disturbances inside the carotid and vertebral arteries and those with intraoperative mean arterial pressure below 50 mmHg were excluded from the study.

Statistical Analysis: Data were analyzed using SPSS 15.0 for Windows (SPSS Inc., Chicago, IL, USA). The two groups were compared using the Mann-Whitney U-test. The comparison between the groups was done with Wilcoxon's signed ranks test. The correlations were analyzed using Spearman's rho test.

Results: There were no significant differences between the two groups in S100B protein concentration before the surgery. Just after the operation, the S100B protein concentration was elevated in both groups, but its level in the cemented group was significantly higher, particularly just after the surgery, and its normalization was slower than in the cementless group. The comparison of time points within each group revealed that there were no significant differences in patients' reaction time in the simple reaction test before and after the surgery (p = 0.056 and 0.163 in the cementless and 0.581 and 0.139 in the cemented groups), but a significantly longer mean reaction time in the choice reaction test was observed within each group after the surgery (p = 0.003 and 0.001 in the cementless and 0.001 and 0.014 in the cemented groups). There were no correlations between S100B protein plasma concentration and the results of the neuropsychological tests.

Conclusions: There was a relationship between bone cement implantation during primary hip arthroplasty and elevated S100B protein plasma concentration during the short postoperative period, but the results of the neuropsychological tests did not reflect this.