Hoffmann Daniel E, Kowaleski Michael P, Johnson Kenneth A, Evans Richard B, Boudrieau Randy J
Department of Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA.
Vet Surg. 2011 Apr;40(3):311-20. doi: 10.1111/j.1532-950X.2011.00807.x. Epub 2011 Mar 1.
To evaluate the effect of tibial tuberosity advancement (TTA) on cranial tibial thrust (CrTT), retropatellar force (RPF), patellar tendon load (PTL), and patellar tendon angle determined by the tibial plateau angle (PTA(TPA) ) method or common tangent (PTA(CT) ) method in the canine cranial cruciate ligament (CrCL)-deficient stifle joint.
Ex vivo cadaver study.
Cadaveric canine hind limbs (n=30).
Stifle joints were subjected to 3 differing loading conditions using a constrained limb press model (Group 1: 30% body weight axial load at stifle and talocrural joint angles of 135 ± 5° and 145 ± 5°, respectively; Group 2: 30% body weight axial load at stifle and talocrural angles of 145 ± 5° and 135 ± 5°, respectively; and Group 3: 50% body weight axial load at stifle and talocrural joint angles of 135 ± 5° and 145 ± 5°, respectively). The CrCL was transected in situ under load; sensors allowed direct measurement of CrTT, RPF, and PTL. Lateral radiographic projections were used to assess PTA(TPA) and PTA(CT) . Descriptive statistics were used to report CrTT (by design this force returned to 0-point values, defined as the neutral point of advancement [NPA]). At the NPA, RPF was compared with baseline using a 2-tailed sign test. PTL within groups were compared using a paired t-test; pair-wise comparisons of PTA(TPA) and PTA(CT) were performed using a paired t-test. Comparisons between loading conditions were made with a 1-way ANOVA and Tukey's post hoc test. Equivalence tests were used to test mean PTA(TPA) and PTA(CT) for equivalence to 90°. Significance was set at a P-value of .05.
CrTT returned to baseline values, and RPF and PTL at NPA were reduced below baseline values in all specimens in a near linear fashion with TTA. At the NPA, PTA(TPA) >PTA(CT) in 2 of the 3 loading conditions, but insufficient evidence to suggest they differed in the third. Mean PTA(TPA) and PTA(CT) varied between loading conditions. The threshold for each of the groups evaluated, at which the PTA could be significantly different from 90°, was larger for PTA(TPA) than PTA(CT) in all groups, as greater variation was observed with PTA(TPA) versus PTA(CT) .
This study further supports the claim that reduction of CrTT occurs after TTA in the CrCL-deficient stifle joint through an alteration of PTA. Additionally, RPF and PTL also decrease after TTA. The PTA(CT) may be a more precise method of determining PTA.
评估胫骨结节前移术（TTA）对犬类前交叉韧带（CrCL）损伤的 stifle 关节中胫骨前向推力（CrTT）、髌股后向力（RPF）、髌腱负荷（PTL）以及通过胫骨平台角（PTA(TPA)）法或公切线（PTA(CT)）法测定的髌腱角的影响。
体外尸体研究。
犬类尸体后肢（n = 30）。
使用受限肢体按压模型对 stifle 关节施加 3 种不同的负荷条件（第 1 组：在 stifle 关节和距小腿关节角度分别为 135±5°和 145±5°时施加 30%体重的轴向负荷；第 2 组：在 stifle 关节和距小腿关节角度分别为 145±5°和 135±5°时施加 30%体重的轴向负荷；第 3 组：在 stifle 关节和距小腿关节角度分别为 135±5°和 145±5°时施加 50%体重的轴向负荷）。在负荷下原位切断 CrCL；传感器可直接测量 CrTT、RPF 和 PTL。使用外侧 X 线投影评估 PTA(TPA)和 PTA(CT)。采用描述性统计报告 CrTT（根据设计，此力恢复到 0 点值，定义为前移中性点 [NPA]）。在 NPA 处，使用双侧符号检验将 RPF 与基线进行比较。组内 PTL 使用配对 t 检验进行比较；PTA(TPA)和 PTA(CT)的两两比较使用配对 t 检验。负荷条件之间的比较采用单因素方差分析和 Tukey 事后检验。使用等效性检验来检验平均 PTA(TPA)和 PTA(CT)是否等效于 90°。显著性设定为 P 值为 0.05。
CrTT 恢复到基线值，并且在所有标本中，NPA 处的 RPF 和 PTL 随着 TTA 以近似线性的方式降低至基线值以下。在 NPA 处，3 种负荷条件中的 2 种情况下 PTA(TPA)>PTA(CT)，但在第 3 种情况下没有足够证据表明它们存在差异。平均 PTA(TPA)和 PTA(CT)在不同负荷条件下有所变化。在所有组中，对于评估的每个组，PTA(TPA)比 PTA(CT)与 90°有显著差异的阈值更大，因为观察到 PTA(TPA)相对于 PTA(CT)的变化更大。
本研究进一步支持以下观点，即在 CrCL 损伤的 stifle 关节中，TTA 后通过改变 PTA 可使 CrTT 降低。此外，TTA 后 RPF 和 PTL 也会降低。PTA(CT)可能是一种更精确的测定 PTA 的方法。
