Einfluss der Knochendichte des Tibiakopfes auf die Frühlockerung/Migration von Tibiakomponenten

Examination of a possible correlation between the bone density of resected tibial plateaus determined by CT and MRI and migration of tibial joint replacements determined by radiostereometry. 2-year results of micromotion of tibial joint replacement in 11 patients with total knee replacement could be ascertained using radiostereometric analysis (RSA). This migration (lateral or medial subsidence) has been correlated with the bone density determined by CT-osteodensitometry (content of Ca+2-HA / ml) and MR-osteodensitometry (T2*, TR 153 ms, TE 2,7 ms). The bone density determined by CT-osteodensitometry (CT-ODM) correlates in 6 of 11 patients with the MRI measurements (MR-ODM). Results in CT-ODM and RSA-analysis correlate in 6 of 11 patients. The MR-ODM results correlate with the RSA in 6 of 11 patients. A correlation between CT-ODM, MR-ODM and RSA can only be seen in 3 of 11 patients. The RSA is an established method for the determination of early loosening of implanted arthroplasties. No proof for a significant correlation between the migration analysis and the bone density determined by CT-ODM or MR-ODM was found. Based on these results the bone density determined by CT-ODM or MR-ODM in resected tibial plateaus is not a suitable predictor of expected migration. These results should be checked using a greater number of patients.