DISLOCATIONS. 263 



series of movements which would be sim^j/r 'JiposriiiDle with the 

 joint in a state of integrity. Both fractnr(-s and luxations are 

 marked by deformity, but while in a fracture with displacement 

 there vrill usually be a shortening of tha leg, a dislocation may be 

 accompanied by either a shortening or a lengthening. Swelling 

 of the parts is usually a well-defined feature of these injuries. 



With all this similarity in the symptomatology of luxations 

 and fractures, there is one sign which either by its presence or its 

 absence will greatly assist in settling a case of differential diag- 

 nosis, and this is the existence or lack of cre^y'itation. It has no 

 place or cause in a mere dislocation ; it belongs to a fracture, if it 

 is a complete one. If there is crej)itation with a dislocation then 

 it proves that there is a fract:u.re also. 



The prognosis of a luxation is comparatively less serious than 

 that of a fracture, though at times the indications of treatment 

 may prove to be so difficult to apply that compUcations may arise 

 of a very severe character. 



The treatment of luxations must of course be similar to that 

 of fractures. Reduction, naturally, will be the first indication in 

 both cases, and the retention of the replaced parts must follow. 

 The reduction involves the same steps of extension and counter- 

 extension performed in the same manner, with the patient subdued 

 by anesthetics. 



The difference between the reduction of a dislocation and that 

 of a fracture consists in the fact that in the former the object is 

 simply to restore the bones to their true normal position, with 

 each articular surface in exact contact with its companion surface, 

 the apparatus necessary afterwards to keej) them in situ being 

 similar to that which is eraployed in fracture cases, and which will 

 usually requu'e to be retainei for a period of from forty to fifty 

 days, if not longer, before the ruptured retaining ligaments are suffi- 

 ciently firm to be trusted to perform their office unassisted. A vari- 

 ety of manipulations are to be employed by the surgeon, consisting 

 in pushing, pulling, pressing, rotating, and indeed whatever move- 

 ment may be necessary, until the bones are forced into such rela- 

 tive positions that the musdolar contraction, operating in just the 

 right directions, pulls the opposite matched ends together in true 

 coaptation, a head into a cavity, an articular eminence into a 

 trochlea, as the case may be. The "setting" is accompanied by a 



