Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA.
Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA.
Osteoporos Int. 2021 Mar;32(3):549-558. doi: 10.1007/s00198-020-05610-x. Epub 2020 Sep 4.
We investigated the effect of 12 months of functional electrical stimulation-assisted rowing with and without zoledronic acid (ZA) on computationally estimated bone strength and stiffness in individuals with spinal cord injury. We found that rowing with ZA, but not rowing alone, improved stiffness at the distal femur, but not the proximal tibia.
People with spinal cord injury (SCI) have high fracture risk at the knee after the injury. Therapies that prevent bone loss or stimulate an anabolic response in bone have been proposed to reduce fractures. Zoledronic acid (ZA) is a potent bisphosphonate that inhibits osteoclastic resorption. Functional electrical stimulation (FES)-assisted rowing is a potentially osteogenic exercise involving mechanical stimulation to the lower extremities. Here, we investigated the effect of FES-assisted rowing with and without ZA on bone strength and stiffness in individuals with SCI.
Twenty individuals from a cohort of adults with SCI who participated in a clinical trial were included in the study. CT scans of their knees before and after the intervention were converted to finite element models. Bone failure strength (T) and stiffness were calculated at the proximal tibia and distal femur.
T at the distal femur increased 4.6% among people who received rowing + ZA and decreased 13.9% among those with rowing only (p < 0.05 for group). Torsional and compressive stiffness at the femur metaphysis increased in people with rowing + ZA (+ 3 to +4%) and decreased in people with rowing only (- 7 to -8%; p < 0.05). T in the proximal tibia decreased in everyone, but the loss was attenuated in the rowing + ZA group. People with initially stronger bone tended to lose more strength.
Overall, we observed increases in bone strength at the distal femur but not the proximal tibia, with FES-assisted rowing combined with ZA treatment. Rowing alone did not significantly prevent bone loss at either site, which might be attributed to insufficient mechanical loading.
我们研究了 12 个月的功能性电刺激辅助划船，以及联合或不联合唑来膦酸（ZA）对脊髓损伤患者计算得出的骨强度和刚度的影响。我们发现，联合 ZA 的划船运动，而不是单纯的划船运动，改善了股骨远端的刚度，但对胫骨近端没有影响。
脊髓损伤（SCI）患者在损伤后膝关节处骨折风险较高。已经提出了一些治疗方法，以防止骨质流失或刺激骨骼的合成代谢反应，从而减少骨折。唑来膦酸（ZA）是一种有效的双膦酸盐，可抑制破骨细胞的吸收。功能性电刺激（FES）辅助划船是一种潜在的成骨运动，涉及对下肢的机械刺激。在此，我们研究了 FES 辅助划船，以及联合或不联合 ZA 对 SCI 患者的骨强度和刚度的影响。
20 名来自成年人 SCI 队列的参与者参加了这项临床试验，他们的膝关节在干预前后的 CT 扫描被转换为有限元模型。计算了胫骨近端和股骨远端的骨破坏强度（T）和刚度。
接受划船+ZA 的患者股骨远端 T 增加了 4.6%，而单纯划船的患者则减少了 13.9%（组间差异有统计学意义，p<0.05）。股骨干骺端的扭转和压缩刚度在划船+ZA 组中增加了（3 至 4%），而在单纯划船组中则减少了（7 至 8%；p<0.05）。所有人的胫骨近端 T 都减少了，但在划船+ZA 组中减少的幅度较小。初始骨强度较强的患者，其骨强度的损失幅度较大。
总的来说，我们观察到 FES 辅助划船联合 ZA 治疗可增加股骨远端的骨强度，但对胫骨近端没有明显影响。单纯划船运动在两个部位均不能显著防止骨质流失，这可能归因于机械负荷不足。
