Holmes R E, Bucholz R W, Mooney V
J Orthop Res. 1987;5(1):114-21. doi: 10.1002/jor.1100050114.
Porous hydroxyapatite (IP200), formed by conversion of the Poritidae porites exoskeleton, has pores averaging 230 microns and pore interconnections averaging 190 microns in diameter. In the distal radial diaphyses of 14 dogs, bilateral 7.5 X 20 mm cortical windows were created and fitted with 5 X 7.5 X 20 mm blocks of IP200 implants and iliac autografts. Both implanted and contralateral grafted radius specimens were retrieved at 3, 6, 12, 24, and 48 months. Unstained undecalcified sections were examined by microradiography and UV epi-illumination. Stained undecalcified sections were examined by light microscopy and quantitated by histometric methods. Implant specimens demonstrated good union and bone ingrowth at all time intervals. The implant specimens were composed of (mean +/- SE) 10.6% +/- 1.0% soft tissue, 51.2% +/- 1.3% bone, and 38.2% +/- 1.0% IP200. The graft specimens showed good union with little apparent ingrowth at 3 months, followed by progressive appositional closure of cancellous spaces. The graft specimens contained 21.9% +/- 0.9% bone at 3 months with increases at each time interval to 73.1% +/- 8.7% at 48 months. The volume fraction and mean width of IP200 did not change with time, confirming the absence of implant biodegradation. The volume fraction and mean width of bone remained stable in the implant but increased in the graft specimens, corresponding to graft neocortex formation. It is concluded that implants initially filled in with bone while grafts initially replaced much of their spongiosa and subsequently filled in with bone. Histometry of untreated defects and measurement of mechanical properties are suggested for further study.
由鹿角珊瑚外骨骼转化形成的多孔羟基磷灰石（IP200），其平均孔径为230微米，孔隙间连接的平均直径为190微米。在14只犬的桡骨远侧骨干，制造双侧7.5×20毫米的皮质骨窗，并植入5×7.5×20毫米的IP200植入物块和髂骨自体移植物。在3、6、12、24和48个月时取出植入侧和对侧移植的桡骨标本。对未染色的不脱钙切片进行显微放射照相和紫外落射照明检查。对染色的不脱钙切片进行光学显微镜检查，并采用组织计量学方法进行定量分析。植入物标本在所有时间间隔均显示良好的愈合和骨长入。植入物标本由（平均值±标准误）10.6%±1.0%的软组织、51.2%±1.3%的骨和38.2%±1.0%的IP200组成。移植标本在3个月时显示良好的愈合，几乎没有明显的长入，随后松质骨间隙逐渐通过贴壁生长而闭合。移植标本在3个月时骨含量为21.9%±0.9%，在每个时间间隔均有增加，至48个月时达到73.1%±8.7%。IP200的体积分数和平均宽度未随时间变化，证实植入物没有生物降解。植入物中骨的体积分数和平均宽度保持稳定，但移植标本中的骨体积分数和平均宽度增加，这与移植骨新皮质的形成相对应。得出的结论是，植入物最初被骨填充，而移植物最初替换了大部分松质骨，随后被骨填充。建议对未处理的缺损进行组织计量学分析和力学性能测量以作进一步研究。
