66 



E. RuTiSHAUSER et al.: Studies of the Non-inflammatory Vascular Pannus 



Fig. 4. Series III. Rabbit n<. t, 2\ d i) ■, lln 

 mentum teres. To the left, marrow hardly altered, activ 

 marrow (reticulosis). An avascular surface pannus. Alt 

 2 cartilaginous cys 



the ici;iun nt the insertion of the liga- 

 mopoiesis. To the right, ischemic alterations of the 

 f the cartilage due to humoral derangement, 

 ble 



Discussion 



The aim of reproducing relatively simple examples of vascular pannuses was only 

 partly attained in the experiments of Series I and II. The involvement of the articular 

 regions in the circulatory disturbances produced by the injection methods (Series I) 

 is inconstant. When the patella is isolated from its lateral vascular connections 

 (Series II), an effective collateral circulation develops and starts to normalize the 

 local condition after 4 weeks. However, this technique seems to us to be the most 

 satisfactory. The operation is simple and does not entail a direct interference with 

 articular function. The division of the femoral neck initiates a pathological condition 

 which resembles that described by Rokkanen (1962) in his excellent monograph. 

 Experiments of immobilization and remobilization have been carried out by Mastro- 

 MARiNO and Maiotti (1956) on the rabbit and by Evans et al. (1960) on the rat. 

 Here again the histopathological picture resembles that which we have described; 

 however, these authors reach more limited conclusions than those to which our find- 

 ings have led us. In any case, their method is even more complicated than ours. 



Conclusions 



Articular ischemia achieved in the rabbit by different experimental procedures 

 resulted in a typical transformation of the joints concerned. The terminal plate was 

 simultaneously eroded by outgrowths of periosteal and synovial tissue (surface or 

 intra-articular pannuses) and by sprouts of vasculo-reticular tissue from the marrow 

 spaces (internal or medullary pannuses). 



These findings parallel closely certain aspects observed in posttraumatic or 

 gerontologic joint pathology. It is suggested that local ischemia is an essential factor 

 in the pathogenesis of degenerative and postinflammatory arthroses. 



