| Interlocking intramedullary nail was one of the better internal fixation materials for the treatment of humeral shaft fracture ,and the antegrade locked nail was extensively used recently.But it was contraversed nowadays for its complications,for example, it would lead to shoulder sleeve injury and then cause the functional deficit of shoulder. Some authors were trying to use the retrograde locked nail for eliminating such complication.This incision extends from elbow to shoulder,without disturbing the shoulder sleeve.However,there was no definited incision of retrograde locked nail by now.To investigate the best entry hole of retrograde locked nail,where without disturbing the function of the shoulder and the elbow joint,we observed the internal structure of humerus in canvus,and studied the technology of retrograde locked nail.Materials and Methods1. Adopt 10 pieces of adults' cadanvas humeral with strap elbow joint(5 pieces of left, others of right). Saw the humeral from collom chirirgium.put a 7mm or 8mm strap cuspidal straightness iron into cavum medullare,strike the iron softly to make it through bone from far point,which we define 'O'pointMeasure the distance of 'O' to humerus epitrochlea('A' point),to humerus lateral epicondyle('B' point),to fossa olecrani('C' point),and to the point('D' point) which elbow joint capsule attach to olecrani fossa hi saggittal plane.Simultaneously measure the smallest angle of elbow joint which will not hinder the iron strap pass through cavum medullare in physiologic range(0-150 degrees)2. Search for the point of intramedullary nail retrogradationally entering into out of elbow joint capsule .Choose shadowgraph strung of the biggest fact of cavum medullare in the sigittal plane to ensure the entering point.Firstly,sect the humeral shaft as axes of cavum medullare in sigttal plane.,find out the point near to the out of joint caplus ,which is defined as the far point('E'point). Measure the distance of the point to .humerus epitrochlea,to humerus lateral epicondyle and measure the distance from the E point to the medial slide of humeral shaft .Caculate the rate of tranverse distance verus diameter.through 'E' point.Then,use a 8mm width irion plate to pass through the cavum medullare inclining on the side of 'E' point,the other side of the plate is the point 'F',which is the near point of intramedullary nail retrogradationally entering.By the same method,measure the distance of 'F' to 'A','F'to'B'and the distance of 'E'to'F'.Caculate the rate of transverse distance verus diameter through 'F'point.At the sametime ,measure the axes distance of 'F'point to 'C'point to confirm the fit distance upwards to olecrani fossa to ensure intergrity of humerus.3. After confirming the nail entering point ,complete the experiment with 7mm diameter interlocking intremedullary nail by retrogradational way on 10 specimens.ResultsAll the outside points of intremedullary nails are in the elbow caplus.The distances of outside points ('O'point)to 'A' points are 30.2+/-2.2mm, and'O' points to 'B'points are 32.3+/-1.9mm(29mm-35mm),to 'C'points are 13.0+7-0.9 (12mm-15mm),to 'D'points are 4.3+/-0.8mm(3mm-5mm)(tablet 1). Elbow joint will hinder the nail entering unless bended to 120.5+/-1.8 degrees (HSdegrees to 124degrees).(tablet 2).The distances of 'E'points to 'A' points are 35.0+ /-1.6mm(32-37mm),to 'B'points are 37.5+7-1.2mm(36-39mm).The rates through 'E'points are 0.42+/-0.02(0.38-0.44)(tablet3).The distances of'F'points to 'A'points are 52.8+7-3.3mm(48-57mm),to 'B'points are 55.0+/-2.5mm (52-57mm). The rates through 'F'points are 0.43+/-0.02(0.39-0.45)(tablet4).The distances of 'E'points to 'F'points are 25.5+7-0.5mm(24-26mm).(tablets).The distances of 'F'points to 'C'points are 55.2+/-2.4mm(51-59mm)(tablet6).10 specimens are all succeded in putting intremedullary nail into humerus retrogradationally under elbow bending 125 degree,without fracture and fissure.ConclusionTo ensure the success of humerus intremedullary nail retrogradationally,the elbow joint must... |
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