Finnan Ryan P, Prayson Michael J, Goswami Tarun, Miller Danielle
Departments of Orthopaedic Surgery, Wright State University-Boonshoft School of Medicine, Dayton, OH 45409, USA.
J Orthop Trauma. 2010 Jan;24(1):36-41. doi: 10.1097/BOT.0b013e3181b04383.
The mechanical behavior of cadaveric femurs after intramedullary reaming using the Reamer-Irrigator-Aspirator (RIA) for autogenous bone graft harvest has not been fully described. We hypothesized that reamed femurs, regardless of starting point, would adequately withstand cyclic loading simulating postoperative single-leg stance.
Twenty-one cadaveric pairs were randomly assigned to one of three groups based on starting point: Group 1 (trochanteric), Group 2 (piriformis fossa), and Group 3 (retrograde). Each femur underwent dual-energy x-ray absorptiometry scanning and radiographs. Each test femur was reamed to 15 mm using the RIA with the contralateral femur serving as the control. The specimens were loaded to 1400 N of axial compression with 2 degrees simultaneous torsion for 10,000 cycles. If the femur survived cyclic loading, it was then loaded to failure in axial compression. Comparisons regarding survival of cyclic loading were made using Fisher exact test.
No differences were seen between groups regarding age, sex, and T-score. The mean T-score for the femurs was -2.531 +/- 1.372. Overall, 18 of 21 (86%) test femurs and 20 of 21 (95%) control femurs withstood cyclic loading (P = 0.606). Statistical significance was not reached for the three pairwise comparisons between test groups. The femurs failed in patterns consistent with simple pertrochanteric, basicervical, midcervical, or subcapital fractures.
Intramedullary reaming for bone graft harvest using the RIA without subsequent intramedullary stabilization did not significantly degrade the mechanical behavior of cadaveric femurs in simulated single-leg stance regardless of reamer starting point. It appears safe to allow single-leg stance weightbearing on a reamed, unstabilized femur after bone graft harvesting using the RIA.
使用扩髓-冲洗-吸引器（RIA）获取自体骨移植时，尸体股骨在髓内扩髓后的力学行为尚未得到充分描述。我们假设，无论起始点如何，扩髓后的股骨都能充分承受模拟术后单腿站立的循环载荷。
根据起始点，将21对尸体随机分为三组之一：第1组（转子间）、第2组（梨状窝）和第3组（逆行）。每根股骨均接受双能X线吸收测定扫描和X线片检查。使用RIA将每根测试股骨扩髓至15mm，对侧股骨作为对照。将标本轴向压缩加载至1400N，同时施加2度扭转，持续10000个循环。如果股骨在循环加载后存活，则对其进行轴向压缩直至破坏。使用Fisher精确检验对循环加载的存活情况进行比较。
各组在年龄、性别和T值方面无差异。股骨的平均T值为-2.531±1.372。总体而言，21根测试股骨中有18根（86%）和21根对照股骨中有20根（95%）承受了循环加载（P = 0.606）。测试组之间的三次两两比较均未达到统计学显著性。股骨的破坏模式与简单转子间、基底颈、颈中部或头下型骨折一致。
使用RIA进行髓内扩髓获取骨移植，随后不进行髓内固定，无论扩髓起始点如何，在模拟单腿站立时均不会显著降低尸体股骨的力学行为。在使用RIA进行骨移植后，允许在扩髓且未固定的股骨上进行单腿站立负重似乎是安全的。
