William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
Vet Surg. 2021 Aug;50(6):1237-1249. doi: 10.1111/vsu.13655. Epub 2021 May 7.
To determine the influence of interlocking screw threads on the biomechanical properties of repaired canine humeral condylar fractures.
Ex vivo biomechanical study.
Thirty-six humeral condyles.
Simulated fractures of the lateral aspect of the humeral condyle were stabilized by a 3.5 mm interlocking thread screw (ITS) or 3.5 mm buttress thread screw placed in lag (BTS-L) or positional fashion (BTS-P) and axially loaded at a walk, trot, 2-mm displacement, and failure cycles. Compact flute drill bits (CFBs) were used for ITS constructs and standard flute drill bits (SFB) for BTS constructs. The effects of bit type on drilling parameters and screw type on screw insertion properties and fragment stability were assessed.
CFB produced a 6°C greater temperature increase (p = .042) and required 20 N higher torque (p = .003) than SFB. Insertional torque was greater for ITS than BTS-P (p = .001) and BTS-L (p = .001). Condylar fragment rotation at failure was lower in ITS (lsmean ± SE, 8.3° ± 1.9°) than BTS-L constructs (14.5° ± 2.3°, p = .011). ITS resisted greater loads (1503 ± 105 N) than BTS-P (1189 ± 99 N, p = .038) but not BTS-L (1249 ± 123 N, p = .121) constructs.
Biomechanical performance of constructs was improved with ITS rather than BTS fixation.
ITS can be considered for stabilization of humeral condylar fractures in adult dogs.
确定锁定螺纹对修复犬肱骨髁骨折生物力学性能的影响。
体外生物力学研究。
36 个肱骨髁。
通过 3.5mm 锁定螺纹螺钉（ITS）或 3.5mm 支撑螺纹螺钉（BTS-L）或位置固定螺钉（BTS-P）固定肱骨髁外侧模拟骨折，并在步行、小跑、2mm 位移和失效循环下轴向加载。ITS 结构采用紧凑型麻花钻头（CFB），BTS 结构采用标准麻花钻头（SFB）。评估了钻头类型对钻孔参数和螺钉类型对螺钉插入特性和骨折块稳定性的影响。
与 SFB 相比，CFB 产生的温度升高了 6°C（p=0.042），所需扭矩高 20N（p=0.003）。ITS 的插入扭矩大于 BTS-P（p=0.001）和 BTS-L（p=0.001）。与 BTS-L 结构相比，ITS 结构在失效时髁突骨折块的旋转角度较低（lsmean±SE，8.3°±1.9°）（p=0.011）。ITS 比 BTS-P （p=0.038） 但不比 BTS-L （p=0.121） 结构承受更大的载荷（1503±105N）。
与 BTS 固定相比，ITS 固定可改善骨折结构的生物力学性能。
在成年犬中，可考虑使用 ITS 固定稳定肱骨髁骨折。
