Radev Boyko R, Kase Jonathan A, Askew Michael J, Weiner Scott D
Department of Orthopaedic Surgery, Summa Health System, Akron, OH 44309-2090, United States.
J Biomech. 2009 May 29;42(8):1120-6. doi: 10.1016/j.jbiomech.2009.02.005. Epub 2009 Apr 2.
Benign, giant cell tumors are often treated by intralesional excision and reconstruction with polymethylmethacrylate (PMMA) bone cement. The exothermic reaction of the in-situ polymerizing PMMA is believed to beneficially kill remaining tumor cells. However, at issue is the extent of this necrotic effect into the surrounding normal bone and the adjacent articular cartilage. Finite element analysis (ABAQUS 6.4-1) was used to determine the extent of possible thermal necrosis around prismatically shaped, PMMA implants (8-24cc in volume), placed into a peripheral, sagittally symmetric, metaphyseal defect in the proximal tibia. Temperature/exposure time conditions indicating necrotic potential during the exotherm of the polymerizing bone cement were found in regions of the cancellous bone within 3mm of the superior surface of the PMMA implant. If less than 3mm of cancellous bone existed between the PMMA implant and the subchondral bone layer, regions of the subchondral bone were also exposed to thermally necrotic conditions. However, as long as there were at least 2mm of uniform subchondral bone above the PMMA implant, the necrotic regions did not extend into the overlying articular cartilage. This was the case even when the PMMA was in direct contact with the subchondral bone. If the subchondral bone is not of sufficient thickness, or is not continuous, then care should be taken to protect the articular cartilage from thermal damage as a result of the reconstruction of the tumor cavity with PMMA bone cement.
良性巨细胞瘤通常采用病灶内切除并用聚甲基丙烯酸甲酯（PMMA）骨水泥进行重建治疗。原位聚合PMMA的放热反应被认为能有效杀死残留的肿瘤细胞。然而，问题在于这种坏死效应波及周围正常骨组织和相邻关节软骨的程度。采用有限元分析（ABAQUS 6.4 - 1）来确定将棱柱形PMMA植入物（体积为8 - 24立方厘米）置于胫骨近端外周矢状对称干骺端缺损处时，周围可能发生热坏死的范围。在PMMA植入物上表面3毫米范围内的松质骨区域发现了聚合骨水泥放热过程中显示坏死可能性的温度/暴露时间条件。如果PMMA植入物与软骨下骨层之间的松质骨厚度小于3毫米，软骨下骨区域也会暴露于热坏死条件下。然而，只要PMMA植入物上方至少有2毫米均匀的软骨下骨，坏死区域就不会延伸到上方的关节软骨。即使PMMA与软骨下骨直接接触，情况也是如此。如果软骨下骨厚度不足或不连续，那么在用PMMA骨水泥重建肿瘤腔时，应注意保护关节软骨免受热损伤。
