桡骨小头切除后尺骨冠状突丢失高度对肘关节稳定性影响的体外研究

探讨桡骨小头粉碎性骨折并冠状突骨折行桡骨小头切除后不同部位的尺骨冠状突高度丢失对肘关节稳定性的影响。方法选取正常的防腐新鲜尸体标本20具,对其进行标本的制备。取制备好的尸体5具(10侧)行桡骨小头切除术,桡骨小头切除是在环状韧带上缘平面。将15具(30侧)尸体按随机数字表法分为A、B、C 3组,每组10侧。3组分别于冠状突高度2mm处、冠状突高度1/4处、冠状突高度1/2处截骨,分别测量肘关节屈曲0°、30°、60°、90°、120°时外翻角度的变化。结果当尺骨冠状突高度2mm处及冠状突高度1/4处截骨时肘关节屈、伸活动度不受限及稳定性不受影响;当冠状突高度1/2处截骨时肘关节屈、伸活动度较受限及稳定性受影响;当冠状突高度3/4处截骨时肘关节活动度受限及不稳定;当冠状突基底部截骨时肘关节活动度受限及严重不稳定。B、C 2组在肘关节屈曲为0°、30°、60°、90°、120°时尺骨冠状突丢失高度2mm、1/4截骨的肘关节外翻角度与A组比较差异均无统计学意义(均P>0.05);A、B、C 3组在肘关节屈曲为30°、60°、90°、120°时尺骨冠状突丢失高度1/2截骨的肘关节外翻角度与A、B、C 3组在尺骨冠状突丢失高度2mm、1/4截骨时比较差异均有统计学意义(均P<0.05)。结论尺骨冠状突骨折不超过冠状突原高度的1/4时,对肘关节稳定性无显著影响,行手术摘除碎骨片不会影响肘关节功能;当尺骨冠状突骨折超过原高度的1/2时,会明显影响肘关节稳定性,在行复位内固定的同时,并保持冠状突的高度达到原高度的1/2以上。

Effect of Loss of Ulna Coronoid Process Height on Stability of Elbow Joint after Radial Head Excision in Vitro

Objective To investigate the effect of the loss of ulna coronoid process height in different parts on the stability of elbow joint after radial head excision for radial head comminuted fracture complicated with coronoid process fracture.Methods Twenty preservative fresh cadavers were used for the preparation of specimens.Radial head resection was performed at upper edge of annular ligament in 5 cadaver specimens(10 sides).The other 15 specimens(30 sides) were,respectively,treated with osteotomy at 2 mm,1/4 and 1/2 of coronoid process height in group A,group B and group C,with 10 sides in each group.The changes in valgus angle were measured at 0,30,60,90 and 120 degrees of elbow joint flexion.Results The osteotomy at 2 mm and 1/4 of coronoid process height resulted in unrestricted elbow flexor and extensor activity and unaffected stability.But,elbow flexor and extensor activity and the stability were,respectively,restricted and affected mildly by the osteotomy at 1/2 of coronoid process height,moderately by the osteotomy at 3/4 of coronoid process height,and severely by the osteotomy at the base of coronoid process height.The valgus angles at 0,30,60,90 and 120 degrees of elbow joint flexion in group A were not significantly different from those in group B and C when osteotomy was performed at 2 mm and 1/4 of coronoid process height(P>0.05).In addition,the valgus angles at 30,60,90 and 120 degrees of elbow joint flexion induced by osteotomy at 1/2 of coronoid process height were obviously different from those induced by osteotomy at 2 mm and 1/4 of coronoid process height(all P<0.05).Conclusion Ulna coronoid process fractures at height not greater than 1/4 of coronoid process has no significant effect on elbow joint stability and surgical removal of bone chips will not affect the function of elbow joint.However,coronoid process fractures at height greater than 1/2 of coronoid process can markedly affect elbow joint stability.Therefore,coronoid process height should be kept greater than 1/2 of original height in the reduction and internal fixation of radial head comminuted fracture complicated with coronoid process fracture.