摘要目的 探讨在不同轴向应力作用下,不同骨折愈合时期骨折端骨痂愈合的CT影像结果. 方法 取32只青山羊,均行股骨干中段横行截骨制作骨折模型,按骨折端不施加应力(对照组)和施加实验动物自身体质量的1/6(A组)、1/3(B组)、1/2(C组)应力分为4组,每组8只.术后4、8周分批处死,每次每组处死4只,CT扫描测量骨折端骨外膜骨痂平均CT值(HU)、平均面积及骨折端对位情况. 结果 术后4周,对照组、A组、B组、C组骨折端骨外膜骨痂平均HU值分别为164.9±16.8、214.4±27.3、287.7±30.6、313.6±33.5;骨外膜骨痂面积平均分别为(0.40±0.15)、(0.78±0.19)、(0.84±0.22)、(0.88±0.21) cm2.与对照组比较,A组、B组、C组骨外膜骨痂HU值、面积均较大;与A组比较,B、C组膜骨痂HU值较大,差异均有统计学意义(P＜0.05).术后8周,对照组、A组、B组、C组骨折端骨外膜骨痂平均HU值分别为334.3±38.1、415.6±45.1、505.8±45.6、512.8±41.8;骨外膜骨痂面积平均分别为(0.70±0.21)、(1.11±0.23)、(1.63±0.28)、(1.65±0.20) cm2.与对照组比较,A组、B组、C组骨外膜骨痂HU值、面积均较大;与A组比较,B、C组骨外膜骨痂平均HU值、平均面积较大,差异均有统计学意义(P＜0.05).同一组内术后4与术后8周骨外膜骨痂HU值比较差异均有统计学意义(P＜0.05).B、C组术后4周与术后8周骨外膜骨痂面积值比较差异有统计学意义(P＜0.05).对照组、A组、B组、C组骨折端分别有1、1、2、4例发生不同程度成角畸形.结论 骨折端施加轴向应力时能促进骨折端骨痂生长,较大的应力强度能更好地促进骨折端骨痂生长,但同时会导致骨折愈合成角畸形发生率增高,骨折端施加自身体质量的1/3倍应力骨折端成角畸形发生率较低,较适宜促进骨折端骨痂生长.

abstractsObjective To observe by CT images the effects of controlled axial stresses on the healing of fracture ends at different stages.Methods Thirty-two grey goats were randomized into 4 equal groups (n =8),in which stresses of 0 (control group),1/6 (group A),1/3 (group B) and 1/2 (group C) of their body weight were applied respectively.Transverse osteotomy at the middle shaft of the femur was performed in all groups to create animal fracture models.The goats were sacrificed in batch at 4 and 8 weeks after operation separately for CT scanning and measurement of the Hounsfield unit (HU) and callus area at the fracture ends.Results At 4 weeks after operation,the average HU of bony callus at the fracture ends was 164.9 ± 16.8,214.4 ±27.3,287.7 ±30.6 and 313.6 ±33.5 respectively in control group and groups A,B and C;the callus area at the fracture ends was 0.40 ±0.15 cm2,0.78 ±0.19 cm2,0.84 ±0.22 cm2 and 0.88 ±0.21 cm2 respectively in control group and groups A,B and C.On average,groups A,B and C had significantly higher HU and significantly large callus area than control group while groups B and C had significantly higher HU than group A (P ＜ 0.05).At 8 weeks after operation,the average HU of bony callus at the fracture ends was 334.3 ±38.1,415.6 ±45.1,505.8 ±45.6 and 512.8 ±41.8 respectively in control group and groups A,B and C;the callus area at the fracture ends was 0.70 ±0.21 cm2,1.11 ±0.23 cm2,1.63 ± 0.28 cm2 and 1.65 ± 0.20 cm2 respectively in control group and groups A,B and C.On average,groups A,B and C had significantly higher HU and significantly large callus area than control group while groups B and C had significantly higher HU and significantly large callus area than group A (P ＜ 0.05).There were significant differences between the 4 and 8 weeks after operation in average HU of bony callus in all the 4 groups (P ＜ 0.05).There were also significant differences between the 4 and 8 weeks after operation in average callus area in groups B and C (P ＜ 0.05).Angulation deformity of the fracture ends was observed in one case in control group,in one in group A,in 2 cases in group B and in 4 in group C.Conclusions As stress at the fracture ends can improve callus formation,it can be strengthened to enhance the effect,but a strengthened stress at fracture ends may increase incidence of angulation deformity during fracture healing.Application of a stress of 1/3 of the body weight may promote callus formation at fracture ends with a low incidence of angulation deformity.