Lockwood W Charles, Marchetti Daniel Cole, Dahl Kimi D, Mikula Jacob D, Williams Brady T, Kheir Matthew M, Turnbull Travis Lee, LaPrade Robert F
Department of BioMedical Engineering, Steadman Philippon Research Institute, 181 W. Meadow Drive, Suite 1000, Vail, CO, 81657, USA.
The Steadman Clinic, Vail, CO, USA.
Knee Surg Sports Traumatol Arthrosc. 2017 Jan;25(1):138-143. doi: 10.1007/s00167-016-4317-5. Epub 2016 Sep 13.
In order to minimize viscoelastic elongation of ACL reconstruction grafts, preconditioning protocols have been employed in clinical practice prior to final graft fixation. The purpose of this study was to evaluate two separate high-load static preconditioning protocols of double-looped semitendinosus-gracilis grafts and compare these results to both a current clinical protocol and a control group with no preconditioning protocol applied. It was hypothesized that a high-load, static preconditioning protocol would minimize graft elongation during a simulated progressive early rehabilitation compared to both the "89 N" clinical protocol and control groups.
Grafts were randomly allocated into four preconditioning study groups: (1) control (no preconditioning), (2) clinical protocol (89 N for 15 min), (3) high-load, short duration (600 N for 20 s), and (4) high-load, long duration (600 N for 15 min). After preconditioning, grafts were cyclically loaded between 10 and 400 N at 0.5 Hz for 450 cycles to simulate early postoperative rehabilitation. Graft displacement (elongation) was recorded during both preconditioning and cyclic loading.
Increased preconditioning load magnitude and duration significantly reduced graft elongation during cyclic loading (p < 0.05) which corresponded to an inverse relationship with increased elongation during preconditioning. The "600 N for 15 min" protocol resulted in significantly less elongation during simulated early rehabilitation than both the control group and the "89 N for 15 min" protocol (p < 0.001, p < 0.05).
Graft elongation during simulated early rehabilitation was significantly reduced by a high-load preconditioning protocol applied for an extended period of time compared to a current common clinical protocol and grafts that were not preconditioned. In addition, the amount of elongation during simulated early rehabilitation was similar between grafts preconditioned using the current clinical practice protocol and the high-load/short-duration protocol, implying that the latter could potentially induce the same viscoelastic changes in soft tissue grafts as the current clinical practice. The "600 N for 20 s" preconditioning protocol may provide similar postoperative results as the clinical protocol, "89 N for 15 min", and also reduce or maintain operative time. A high-load preconditioning protocol that reduces graft elongation may benefit patients undergoing ACL reconstruction, especially for cases of failed primary reconstruction, genu recurvatum, and increased tibial slope, where maintaining graft length is imperative to restore knee stability.
为了尽量减少前交叉韧带重建移植物的粘弹性伸长，在最终固定移植物之前，临床实践中采用了预处理方案。本研究的目的是评估双环半腱肌-股薄肌移植物的两种不同的高负荷静态预处理方案，并将这些结果与当前的临床方案以及未应用预处理方案的对照组进行比较。研究假设是，与“89 N”临床方案和对照组相比，高负荷静态预处理方案将在模拟的早期渐进性康复过程中使移植物伸长最小化。
将移植物随机分为四个预处理研究组：（1）对照组（无预处理），（2）临床方案组（89 N，持续15分钟），（3）高负荷、短时间组（600 N，持续20秒），（4）高负荷、长时间组（600 N，持续15分钟）。预处理后，以0.5 Hz的频率在10至400 N之间对移植物进行循环加载450次循环，以模拟术后早期康复。在预处理和循环加载过程中记录移植物位移（伸长）。
预处理负荷大小和持续时间的增加显著降低了循环加载过程中的移植物伸长（p < 0.05），这与预处理过程中伸长增加呈反比关系。“600 N，持续15分钟”方案在模拟早期康复过程中导致的伸长明显少于对照组和“89 N，持续15分钟”方案（p < 0.001，p < 0.05）。
与当前常见的临床方案和未进行预处理的移植物相比，长时间应用的高负荷预处理方案显著降低了模拟早期康复过程中的移植物伸长。此外，使用当前临床实践方案预处理的移植物与高负荷/短时间方案预处理的移植物在模拟早期康复过程中的伸长量相似，这意味着后者可能会在软组织移植物中诱导与当前临床实践相同的粘弹性变化。“600 N，持续20秒”预处理方案可能提供与临床方案“89 N，持续15分钟”相似的术后结果，并且还可以减少或维持手术时间。减少移植物伸长的高负荷预处理方案可能会使接受前交叉韧带重建的患者受益，特别是对于初次重建失败、膝反屈和胫骨坡度增加的病例，在这些病例中保持移植物长度对于恢复膝关节稳定性至关重要。
