In vitrostrength comparison of hydroxyapatite cement and polymethylmethacrylate in subchondral defects in caprine femora

Kevin Crawford; B. Hudson Berrey; William A. PierceRobert D. Welch

摘要

AbstractHydroxyapatite cement was investigatedin situfor the reconstruction of juxta‐articular defects. Polymethylmethacrylate is currently the most commonly used material for the reconstruction of bone defects following the exteriorization and curettage of aggressive benign tumors.In vitro, we compared the effects of hydroxyapatite cement and polymethylmethacrylate in restoring the stiffness of the subchondral plate in a caprine femoral defect model, fen matched pairs of caprine femora underwent nondestructive compression testing normal to the load‐bearing surface. A standardized subchondral defect 12 mm in diameter was created in the medial femoral condyle. Compression testing was repeated to determine the reduction in stiffness caused by the defect. Each femur from each pair was randomly assigned to one of two groups (n = 9), and the defects were augmented with either polymethylmethacrylate or hydroxyapatite cement. After 12 hours, compression tcsting/vas repeated to determine the subchondral stiffness after augmentation. Compared with intact femora, the defect specimens that were later treated with either polymethylmethacrylate or hydroxy‐npatite cement exhibited stiffness values of 70 (386 ± 107 N/mm) and 59 (343 ± 94 N/mm) respectively, which represented a significant reduction in stiffness (p = 0.05). Augmentation with polymethylmethacrylate or hydroxyapatite cement restored stiffness by 81 (450 111 N/mm) and 71 (413 ± 115 N/mm), respectively, of tile values of intact specimens. Hydroxyapatite cement restored stiffness significantly (p = 0.05) over the stiffness of the nonaugmented defect compared with the stiffness after augmentation with polymethylmethacrylate (p = 0.12). Neither polymethylmethacrylate nor hydroxyapatite cement restored stiffness to that of intact femora (p = 0.05). In the current defect model, hydroxyapatite cement was comparable with poly‐moihylmethacrylate in restoring subchondral stiffness. Unlike polymethylmethacrylate, however, hydroxy‐apalile cement has the following advantages: it is osteoconductive, is replaced by host bone, and avoids the potential for thermal necrosis. Hydroxyapatite cement may therefore provide a viable alternative to poly‐methylmethacrylate lor augmentation of juxta‐articular and ot

In vitrostrength comparison of hydroxyapatite cement and polymethylmethacrylate in subchondral defects in caprine femora

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