posttraumatic avascular necrosis ( avn ) of the scaphoid is a common complication probably due to the precarious blood supply .
the rate of incidence is about 13% to 40% and almost all are seen in the proximal fragment [ 2 , 3 ] .
careful review of the literature revealed six cases of distal avn in three studies [ 4 , 5 , 6 ] .
the diagnosis of avn of the scaphoid is made by combining the mri findings with direct observation of the punctuate bleeding during the operation .
however , the diagnosis of avn is suspicious in these cases , as mri investigation had been performed in one case   and preoperative bleeding was observed in the other .
here , we report four new cases , all with the correlation of mri and punctuate bleeding .
the series consisted of four patients aged 29 , 33 , 53 and 57 years .
all had a history of scaphoid fracture following a fall on an outstretched hand 35 years ago , and all had been treated by casting before .
radiographic examination revealed suspected areas , such as sclerosis and/or cystic changes , on the distal pole of the scaphoid ( figure 1 ) and mri views were identical with avn of the distal pole , showing hyperintense changes ( figure 2 ) . 

tourniquet was deflated in order to observe punctuate bleeding ; it was observed in three cases and the patients were treated by bone grafting and wire fixation ( figure 3 ) in the remaining , there was no punctuate bleeding despite drilling and the scaphoid was excised and radial advancement osteotomy ( figure 4 ) was performed . 

treated by bone grafting and wire fixation . 
 
 scaphoid was excised and radial advancement osteotomy . 
 
all patients were evaluated by quick disabilities of shoulder , arm , and hand score 711 years after the operation by telephone interview . according to this score , 11 questions related to daily living
posttraumatic avn of the scaphoid occurs as a result of impairment of the vascular supply to the involved bone fragment .
several studies had demonstrated a strikingly poor blood supply to the proximal pole , particularly in comparison with the abundant supply to the distal two - thirds of the scaphoid [ 1 , 2 ] .
review of the literature revealed six cases in three reports [ 4 , 5 , 6 ] .
, avn in the distal fragment occurs if the volar vessel is damaged and the fracture line is distal to the line of entry of the dorsal vessels .
another explanation maybe the anomalous different vascularization of the distal pole [ 5 , 6 , 9 ] .
the diagnosis of avn of the scaphoid was made by combining the mri findings with direct observation of the punctuate bleeding during the operation .
however , there is no such approach in the previously described cases [ 4 , 5 , 6 ] . in the case of sherman et al . , mri was not available and there was no chance to observe bleeding , as the patients had refused surgical treatment .
similarly , in the case of the garg et al . , although mri suggested avn , the patient had been treated conservatively , so there was no chance for punctuate bleeding , and the fracture united .
the diagnosis is also suspicious in this case as no correlation was possible and the fracture had healed .
according to herbert , avn means irreversible necrosis or death of bone and healing is impossible .
only one case had been operated . in this case , the authors had confirmed avn by the pinning attempt that had failed .
there seems no such method for the diagnosis of avn , so the diagnosis is again in doubt . in our opinion
, all these cases should be labeled as suspected avn . in three of our cases , although preoperative mri suggested avn ( figure 2 ) , punctuate bleeding was observed during the operation and all were treated by pinning and grafting and healed uneventfully . in those cases , the appearance of avn was probably due to the normal marrow of bone that has not been established yet , but bleeding was observed due to revascularition . in the remaining case , mri suggested avn along with lack of punctuate bleeding and scaphoid was excised and radial advancement osteotomy was performed . in conclusion , all six cases reported before [ 4 , 5 , 6 ] , and three of our cases that were treated by pinning and had healed , were not real avn or the diagnosis was doubtful .
so our fourth case seems to be a unique case of distal pole avn of the scaphoid in the literature .
 abstractavascular necrosis ( avn ) of the scaphoid predominantly occurs in the proximal pole . 
 review of the literature revealed only six cases and all are suspect due to the lack of either mri investigation or investigation of bleeding preoperatively . 
 we report four new cases and one of them appears to be a real distal pole avn of the scaphoid in the literature . 