CAJ | 학술논문

目的研究内侧皮质缺损对肱骨近端骨折锁定钢板内固定轴向稳定性的影响。方法12对成人防腐肱骨,采用标准的截骨法制作肱骨近端两部分(外科颈骨折)模型。随机分为对照组与内侧皮质缺损组(肱骨近端力线正常,内侧皮质缺损5 mm)。对上述分组实验标本在预载荷：50 N,载荷速率：5 mm/min,最大位移5 mm 的实验条件下进行剪切与轴向压缩测试。结果在轴向加压时内侧皮质缺损1/2组的位移-载荷刚度为(218.7±64.3)N/mm；内侧皮质缺损1/4组为(727.8±66.9)N/mm；内侧皮质完整组为(804.7±80.5)N/mm。内侧皮质少量缺损不会导致骨折内固定的轴向稳定性显著下降(t =-1.263,P >0.05),但较大的内侧皮质缺损则会明显降低内固定的轴向稳定性(t =-22.572,P <0.05)。在骨折模型的肱剪切力对比中,内侧皮质缺损1/2组的位移载荷刚度为(207.3±55.5)N/mm；内侧皮质缺损1/4组为(553.5±33.9)N/mm；内侧皮质完整组为(602.7±66.7)N/mm。内侧皮质少量缺损不会导致骨折内固定的轴向稳定性显著下降(t =-5.41, P >0.05),但较大的内侧皮质缺损则会明显降低内固定的轴向稳定性(t =-19.171,P <0.05)。结论内侧皮质缺损大大降低了肱骨近端骨折内固定后的轴向稳定性。临床实践中应重视对内侧皮质缺损的重建及固定。
목적연구내측피질결손대굉골근단골절쇄정강판내고정축향은정성적영향。방법12대성인방부굉골,채용표준적절골법제작굉골근단량부분(외과경골절)모형。수궤분위대조조여내측피질결손조(굉골근단력선정상,내측피질결손5 mm)。대상술분조실험표본재예재하：50 N,재하속솔：5 mm/min,최대위이5 mm 적실험조건하진행전절여축향압축측시。결과재축향가압시내측피질결손1/2조적위이-재하강도위(218.7±64.3)N/mm；내측피질결손1/4조위(727.8±66.9)N/mm；내측피질완정조위(804.7±80.5)N/mm。내측피질소량결손불회도치골절내고정적축향은정성현저하강(t =-1.263,P >0.05),단교대적내측피질결손칙회명현강저내고정적축향은정성(t =-22.572,P <0.05)。재골절모형적굉전절력대비중,내측피질결손1/2조적위이재하강도위(207.3±55.5)N/mm；내측피질결손1/4조위(553.5±33.9)N/mm；내측피질완정조위(602.7±66.7)N/mm。내측피질소량결손불회도치골절내고정적축향은정성현저하강(t =-5.41, P >0.05),단교대적내측피질결손칙회명현강저내고정적축향은정성(t =-19.171,P <0.05)。결론내측피질결손대대강저료굉골근단골절내고정후적축향은정성。림상실천중응중시대내측피질결손적중건급고정。
Background Proximal humeral fracture is a common injury of shoulder girdle. Currently,locking plate was widely used in management of proximal humeral fractures.Known as“internal fixator”,locking plate can provide more purchase in osteoporosis humeral head,bearing more biomechanical advantages.However,some large series of clinical research showed varus deformity became one of the main complication of proximal humeral fractures treated with locking plate that caused by axial instability.Multi-center trail found that medial cortex defect of proximal metaphyseal of humerus was an independent risk factor of reduction loss and varus malunion.Furthermore,such pathophysiological biomechanic basis was still vague.Our research was planned to study the relationship between medial cortex defect and axial stability of locking plate fixed proximal humeral fracture,in order to find inner rule of how medial cortex defect affect locking plate fixation of proximal humeral fracture.Methods Eighteen adult humerus specimen(6 pairs male),average death age 63.4 years(49-73).All the specimen were excluded bone tumor and occult fracture.Fracture model were prepared at X-Y table.Specimen were cut to 200mm from proximal to shaft.Fracture line was cut at surgical neck perpendicular to humeral shaft.Five millimeter medial cortex defect were also created by T-Saw.All the specimen were fixed using Synthesis PHILOS (Proximal Humerus Internal Osteosythesis System)following AO fixation rules.Specimens were randomized into contrast group, medial cortex half defect group and medial cortex quarter defect group.Axial compression and shear test were done in RGM-40XX2100 machine (Load scale 10 kN,± 1% ).Mechanical Load:Preload:50N,Velocity:5 mm/min,Maximum displacement:5 mm.In axial compression and shear tests,the slope of the load de ection curve was used to compute baseline axial stiffness.Each test was repeated three times and average stiffness was calculated.Statistical analyses were performed with PAWS software (ver.18.0;IBM Inc.,USA).The data were summarized as medians (ranges).The Anova test with LSD correction was applied to detect differences between subgroups.The level of statistical significance was defined as P <0.05.Results In axial compression test,mechanical load stiffness of medial defect half group [(218.7 ± 64.3 )N/mm]was significantly weak than that of contrast group [(804.7 ± 80.5)N/mm]and quarter defect group [(727.8±66.9)N/mm,t =-22.572,P <0.05].In shear force test,it was the same condition that medial cortex half defect group had less stiffness (207.3 ± 55.5 N/mm vs 602.7±66.7 N/mm,t =-1 9.1 71,P <0.05).However,little difference was found between quarter defect group and medial contact group in both axial stiffness (t = -1.263,P >0.05)and shear resistance (t = -5.41,P >0.05 ).Conclusions Medial cortex defect may largely decrease stability of proximal humeral fracture fixed with locking plate in axial compression and shear resistance.In clinical practice,more attention should be payed in reconstruction of such structure.