Robertson D D, Yuan J, Bigliani L U, Flatow E L, Yamaguchi K
Department of Orthopaedic Surgery, Barnes-Jewish Hospital, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
J Bone Joint Surg Am. 2000 Nov;82(11):1594-602. doi: 10.2106/00004623-200011000-00013.
Recreation of normal anatomical relationships may be important to optimize the outcome of proximal humeral arthroplasty. With use of computerized tomographic data and three-dimensional computer modeling, we concurrently studied both extramedullary and intramedullary humeral morphology, including canal shape, and related these findings to the design of proximal humeral prostheses.
Sixty cadaveric humeri (thirty pairs: fifteen from male donors and fifteen from female donors) were studied. Three-dimensional computer models were built from canal and periosteal contours extracted from computerized tomographic data and multiple measured anatomical parameters, including humeral canal axis, humeral head center, and hinge point offset; greater tuberosity and bicipital groove offset; humeral head center, radius, thickness, retroversion, and inclination; and size and torsion of sections of the canal.
On the average, the humeral head center was offset both medially (seven millimeters) and posteriorly (two millimeters) from the humeral axis. The humeral head hinge point did not line up with the axis but instead was laterally offset by an average of seven millimeters. The average humeral head thickness was nineteen millimeters. The humeral head thickness and length were proportionately linked. There was marked variability in all of these parameters. Humeral head inclination averaged 41 degrees but was less variable than previously described, with 95 percent of our sample within the range of 35 to 46 degrees. The proximal section of the humeral canal was retroverted, and the retroversion was found to be similar to that of the humeral head on statistical analysis. Version of the middle and distal sections of the canal, however, was dissimilar to that of the proximal section of the canal. Proximal humeral retroversion was found to be extremely variable and averaged 19 degrees. The accuracy, reliability, and repeatability of the computer-based-model measurements were found to be excellent.
Measurements of external proximal humeral morphology made with three-dimensional computer models of cadaveric specimens derived from the Midwestern United States agreed, in general, with those described for different populations evaluated with different measuring techniques. Proximal humeral morphology was extremely variable as highlighted by the large ranges of measurements seen for all variables. Examination of the intramedullary morphology showed that there is an internal version, with measurements dependent on the canal distance distal to the anatomical neck.
Because of the marked variabilities seen in proximal humeral morphology, newer prosthetic designs are now allowing surgeons to control multiple prosthetic variables. An understanding of the normal values for proximal humeral morphology can serve as an important guideline for component selection, especially when the normal anatomy is distorted. Additionally, variations in intramedullary version may have important consequences for future designs of press-fit proximal humeral replacement.
恢复正常的解剖关系对于优化肱骨近端关节成形术的效果可能很重要。通过使用计算机断层扫描数据和三维计算机建模，我们同时研究了肱骨的髓外和髓内形态，包括髓腔形状，并将这些发现与肱骨近端假体的设计相关联。
研究了60具尸体肱骨（30对：15具来自男性供体，15具来自女性供体）。根据从计算机断层扫描数据中提取的髓腔和骨膜轮廓以及多个测量的解剖参数构建三维计算机模型，这些参数包括肱骨髓腔轴、肱骨头中心和铰链点偏移；大结节和二头肌沟偏移；肱骨头中心、半径、厚度、后倾和倾斜度；以及髓腔各节段的尺寸和扭转。
平均而言，肱骨头中心相对于肱骨干轴线向内侧偏移7毫米，向后偏移2毫米。肱骨头铰链点与轴线不重合，而是平均向外侧偏移7毫米。肱骨头平均厚度为19毫米。肱骨头厚度和长度成比例相关。所有这些参数都存在明显的变异性。肱骨头倾斜度平均为41度，但变异性比先前描述的要小，我们样本的95%在35至46度范围内。肱骨髓腔近端部分是后倾的，经统计分析发现其与肱骨头的后倾相似。然而，髓腔中段和远端部分的扭转与近端部分不同。发现肱骨近端后倾变化极大，平均为19度。基于计算机模型测量的准确性、可靠性和可重复性极佳。
用来自美国中西部尸体标本的三维计算机模型对肱骨近端外部形态进行的测量，总体上与用不同测量技术评估的不同人群的测量结果一致。如所有变量的测量范围所示，肱骨近端形态变化极大。对髓内形态的检查表明存在内部扭转，测量结果取决于解剖颈远端的髓腔距离。
由于肱骨近端形态存在明显变异性，新型假体设计现在允许外科医生控制多个假体变量。了解肱骨近端形态的正常值可作为部件选择的重要指导，尤其是在正常解剖结构变形时。此外，髓内扭转的变化可能对压配式肱骨近端置换的未来设计产生重要影响。
