The Study Of The X-ray Radiocapitellar Line Of Elbow Joint In Chlidren

The injuries of the elbow joint come to the first in incidence of injuries occurring in children, which include the humeral supracondylar fractures, lateral humeral condylar fractures, the total separation of the physis from the distal end of the humerus, the dislocation of the radial head (including the Monteggia fracture), fractures of the lateral humeral condyles along with the dislocation of the elbow joint, humeral intercondylar fractures, the dislocation of the elbow joint. The injured children cannot tell the accident of injuries clearly. The standard radiographic projection of the elbow joint is difficult to be obtained because of the fear of the children, the local swelling of the elbow joint, the limitation of the passive motion of the involved elbow joint. The structural complexity of the elbow joint and discrepancy of the appearing time of the ossification center of the physis lead to the difficulty in the correct diagnosis of the injuries of the elbow joint. The incidence of misdiagnosis and missed diagnosis are considerably high according to several reports both in China and abroad for those reasons above. And the incidence of misdiagnosis of the total separation of the physis from the distal end of the humerus is the highest among the childhood fractures which are often misdiagnosed as the dislocation of the elbow joint.The X-ray radiocapitellar line(RCL) of elbow joint is an important reference factor in the diagnosis and differential diagnosis of the elbow injuries. It appears in almost all the related papers and authoritative textbooks that a line extending the longitudinal axis of the proximal end of radius (radial neck) should pass through the center of the ossification center of the humeral capitellum in all degrees of flexion of the elbow irrespective of the radiographic projection of the elbow and it has be used as a general criterion in diagnosing the elbow fractures. But we found that the results of the radiographic RCL of elbow joint were often affected by some factors such as the different position, the rotation of the forearm, different degrees of the flexion of the elbow, changes in the radiographic projection and the age.Objective Up to now, no intensive study of the RCL of elbow joint in children has beenreported both at home and abroad. This study was designed to verify the accuracy and effectiveness of that criterion so avoiding or inducing the misdiagnosis and missed diagnosis of the elbow injuries in children. The observation, measurement and analysis of the radiographs of the elbow in different position of the normal children were performed.Methods The radiographs of the elbow of 100 normal children(aging from 2 years old to 10.5 years old) and 32 elbow specimens of childhood cadavers were obtained. The radiographs with anteroposterior views of the elbow joint in 90 degrees of supination, 45 degrees of supination, zero degree of rotation, 45 degrees of pronation of the forearm were obtained as well as the lateral views of the elbow in 30 degrees, 60 degrees, 90 degrees, 120 degrees of flexion of the elbow. The classification of the position between the extension line of the longitudinal axis of the radial neck and the physis of the humeral capitellum falls into four types: centre intersection, non-centre intersection, tangent, non-intersection. The centre intersection means the extension line of the longitudinal axis of the radial neck passes through the center of the physis of the humeral capitellum. The non-centre intersection means the extension line passes through the physis rather than the center of the physis. The tangent means the extension line passes through the physis at a tangent. The non-intersection means the extension line does not pass through the center of the physis. The vertical distances (so called head-neck distance) between the extension line of the longitudinal axis of the radial neck and the center of the physis of the humeral capitellum were measured on the radiographs with the types of non-centre intersection, tangent, non-intersection...