Anatomical Institute, University of Basel, Basel, Switzerland.
Int Orthop. 2011 Dec;35(12):1813-9. doi: 10.1007/s00264-011-1308-5. Epub 2011 Jul 7.
Failures in total shoulder replacements are often due to aseptic loosening of the glenoid component; the subchondral bone plate is an important factor governing primary fixation of implant materials. Therefore, we investigated characteristic mineralisation patterns of the subchondral bone plate, which demonstrate long-term stress on articular surfaces, age-related changes, postsurgical biomechanical situations and regions of fixation. Using computed tomography osteo-absorptiometry (CT-OAM), these distribution patterns can be demonstrated in vivo. The aim of this study was to investigate the relationship between subchondral bone-plate mineralisation measured with CT-OAM and the mechanical strength measured by indentation.
A total of 32 cadaverous glenoid cavities were evaluated by CT-OAM and indentation testing. Linear regression was used to compare mineralisation and strength of the subchondral bone plate.
Results showed two patterns of mineralisation distribution. Twenty-eight cavities were related to bicentric distribution pattern and four showed a single maximum. The correlation coefficient between CT-OAM density and subchondral bone-plate strength was determined to be between 0.62 and 0.96 (P < 0.02).
Long-term stress affects not only the subchondral but also the underlying cancellous bone. It therefore can be assumed that mineralisation patterns of the subchondral bone plate continue in cancellous bone. Areas of high density could serve as anchoring locations for orthopaedic implants in resurfacing the glenoid cavity.
全肩关节置换失败通常是由于肩胛盂部件的无菌性松动所致；软骨下骨板是影响植入物材料初始固定的重要因素。因此，我们研究了关节表面长期受力、与年龄相关的变化、术后生物力学情况和固定区域的特征性软骨下骨板矿化模式。使用计算机断层骨吸收测量法（CT-OAM）可以在体内显示这些分布模式。本研究旨在探讨 CT-OAM 测量的软骨下骨板矿化与压痕测量的机械强度之间的关系。
对 32 个尸体肩胛盂腔进行 CT-OAM 和压痕测试评估。采用线性回归比较软骨下骨板矿化和强度。
结果显示两种矿化分布模式。28 个窝与双中心分布模式相关，4 个窝呈单峰分布。CT-OAM 密度与软骨下骨板强度之间的相关系数为 0.62 至 0.96（P < 0.02）。
长期受力不仅影响软骨下骨，也影响下方的松质骨。因此，可以假设软骨下骨板的矿化模式会在松质骨中延续。高密度区域可以作为覆盖肩胛盂腔的骨科植入物的锚固位置。
