部分腕骨融合术对腕关节生物力学影响的实验研究

Experimental study of the biomechanical impact of limited intercarpal arthrodesis on the wrist

目的探讨部分腕骨融合术后腕关节的活动范围、压力负荷及对腕关节生理状态的影响。方法选用12例新鲜腕关节标本随机分为3组,A组舟大小融合术;B组舟骨三角骨切除+头月融合术;C组四角融合+舟骨切除术。通过CSS-44020系列生物力学试验机,用100N力,以5mm/s的速度分别牵引腕关节被动掌屈、背伸、尺偏和桡偏,并测量A、B、C3组标本的活动角度。然后,于腕关节内放置压敏片,用自制的实验架将腕关节固定于中立位,以5N/s的压速对腕关节施压至200N,维持60s后测量压敏片上各组标本的受力面积和压力负荷。结果(1)活动范围A组掌屈(68.4±5.2)°(x-±s,下同)、背伸(51.5±4.6)°、尺偏(24.5±2.3)°、桡偏(15.7±3.4)°。B组掌屈(64.5±7.1)°、背伸(60.0±5.2)°、尺偏(42.4±3.2)°、桡偏(26.9±5.2)°。C组掌屈(61.9±6.6)°、背伸(54.9±5.3)°、尺偏(27.1±3.9)°、桡偏(17.0±4.9)°。(2)腕关节的受力面积A组为(265.00±8.97)mm2。B组为(125.81±5.97)mm2。C组为(164.00±8.43)mm2。(3)负荷压力A组为(53.87±3.07)N/cm2。B组为(112.86±0.74)N/cm2。C组为(55.28±5.11)N/cm2。结论舟大小融合术、舟骨切除+四角融合术对腕关节应力负荷的影响与正常腕关节相比变化不大,而舟三角骨切除+头月融合术对腕关节的影响较大,其应力负荷的增加明显超出了正常腕关节所承受的压力负荷。

Objective To investigate the impact of limited intercarpal arthrodesis on wrist motion, load distribution, and other biomechanical properties. Methods 12 fresh cadaver human forearm specimens were used and were randomly divided into 3 groups, with 4 each. seaphoid-trapezium-trapezoid arthodesis （group A）, seaphoid-triquetrum excision ± capitate-lunate fusion （group B）, and seaphoid excision ± four comer fusion （ group C） were done respectively according to group assignment. These specimens were then placed on the CSS-44020 biomechanical test machine. A force of 100N was exerted to the wrist joint at the speed of 5 mm/s in wrist flexion, extension, radial deviation, and ulnar deviation. Range of motion of the wrists in the 3 groups was measured. Then pressure sensitive films were inserted into the wrist joints to collect data when the wrists were pressed by 200N for 60 seconds at the speed of 5 mm/s in neutral position. Results The range of motion in wrists following limited intercarpal arthrodesis were as follows： （68.4 ± 5.2）°flexion, （51.5 ± 4.6）° extension, （15.7 ± 3.4）° radial deviation, and （24.5 ± 2.3）° ulnar deviation in group A ; （64.5 ± 7.1 ） o flexion, （60.0 ± 5.2）° extension, （26.9 ± 5.2） o radial deviation, and （42.4 ± 3.2）° ulnar deviation in group B; （61.9 ± 6.6）° flexion, （54.9±5.3）° extension, （17.0 ± 4.9）° radial deviation, and （27.1±3.9）° ulnar deviation in group C. Data collected by the pressure sensitive films composed of pressed area and pressure intensity. The pressed areas were （265.00 ± 8.97） mm^2, （125.81 ± 5.97） mm^2, and （164.00±8.43） mm^2 for group A, B, and C respectively. The pressure intensity of the wrist was （53.87±3.07）N/cm^2, （112.86 ±0.74） N/ cm^2, and （55.28 ± 5.11 ） N/cm^2 for group A, B, and C respectively. Conclusion Limited wrist arthrodesis led to decreased range of motion of the wrist and increased wrist load bearing.Scaphoid-trapezium-trapezoid arthodesis and scaphoid excision ＋ four comer fusion resulted in changes that were within the compensation capacity of the wrist, while scaphoid-triquetrum excision ＋ eapitate-lunate fusion caused more dramatic changes of the biomechanical properties of the wrist.