Crawford K, Berrey B H, Pierce W A, Welch R D
Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, USA.
J Orthop Res. 1998 Nov;16(6):715-9. doi: 10.1002/jor.1100160613.
Hydroxyapatite cement was investigated in situ for 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. Ten 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 testing was repeated to determine the subchondral stiffness after augmentation. Compared with intact femora, the defect specimens that were later treated with either polymethylmethacrylate or hydroxyapatite 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 the 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 detect model, hydroxyapatite cement was comparable with polymethylmethacrylate in restoring subchondral stiffness. Unlike polymethylmethacrylate, however, hydroxyapatite 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 polymethylmethacrylate for augmentation of juxta-articular and other bone defects.
对羟基磷灰石骨水泥进行了原位研究，用于关节周围缺损的重建。聚甲基丙烯酸甲酯是目前在侵袭性良性肿瘤切除和刮除术后重建骨缺损时最常用的材料。在体外，我们在山羊股骨缺损模型中比较了羟基磷灰石骨水泥和聚甲基丙烯酸甲酯对恢复软骨下板刚度的效果。十对匹配的山羊股骨进行了垂直于承重面的无损压缩测试。在股骨内侧髁创建一个直径12毫米的标准化软骨下缺损。重复压缩测试以确定缺损导致的刚度降低。每对中的每根股骨随机分配到两组之一（n = 9），缺损分别用聚甲基丙烯酸甲酯或羟基磷灰石骨水泥增强。12小时后，重复压缩测试以确定增强后的软骨下刚度。与完整股骨相比，后来用聚甲基丙烯酸甲酯或羟基磷灰石骨水泥治疗的缺损标本的刚度值分别为70（386±107 N/mm）和59%（343±94 N/mm），这代表刚度显著降低（p = 0.05）。用聚甲基丙烯酸甲酯或羟基磷灰石骨水泥增强分别将刚度恢复到完整标本值的81%（450±111 N/mm）和71%（413±115 N/mm）。与用聚甲基丙烯酸甲酯增强后的刚度相比（p = 0.12），羟基磷灰石骨水泥增强后的刚度相比未增强缺损的刚度有显著恢复（p = 0.05）。聚甲基丙烯酸甲酯和羟基磷灰石骨水泥均未将刚度恢复到完整股骨的水平（p = 0.05）。在当前的缺损模型中，羟基磷灰石骨水泥在恢复软骨下刚度方面与聚甲基丙烯酸甲酯相当。然而，与聚甲基丙烯酸甲酯不同，羟基磷灰石骨水泥具有以下优点：它具有骨传导性，可被宿主骨替代，并且避免了热坏死的可能性。因此，羟基磷灰石骨水泥可能为聚甲基丙烯酸甲酯用于增强关节周围和其他骨缺损提供一种可行的替代方案。
