LAMENESS IN THE HIND LEG 229 



is not difficult to perform nor is its performance fraught with 

 any dangerous complications. In selected subjects about fifty 

 per cent of cases recover in from two to six weeks following this 

 operation. 



Open Tarsal Joint. 



Like the tibia the hock is exposed to frequent injuries and in 

 some cases wounds perforate the joint capsule. When due to 

 calk wounds where horses are kicked, the injury is often on the 

 side of the tarsus (medial or lateral) and such wounds not in- 

 frequently result in infectious arthritis. Horses sometimes jump 

 over wire fences and wounds are inflicted which constitute ex- 

 tensive laceration of the joint capsule. In firing for bone spavin, 

 where a deep puncture is made very near the tibial tarsal (tibio- 

 astragular) joint if infection gains entrance, serious and general- 

 ized infection of the open joint cavity supervenes in some cases. 



Symptomatology. — There is no marked difi^erence in the con- 

 stitutional disturbances which are occasioned in this condition 

 and those encountered in other cases of septic arthritis (previ- 

 ously considered herein) except that there is a difference in tlie 

 degree of resultant derangement and local tissue changes. 

 Chiefly, because of the difficulty encountered in keeping the 

 hock joint in an aseptic condition or securely bandaged, open 

 tarsal joint constitutes a more serious condition than a similar 

 affection of the fetlock. Otherwise, a very similar condition ob- 

 tains and the same diagnostic principles serve here that have 

 been described on page 110 in considering open fetlock joint. 



Treatment. — The same plan that is described in detail for 

 treatment of similar conditions aft'ecting Mie fetlock joint is indi- 

 cated in this affection. Exceeding care must be exercised in 

 bandaging the hock, however, lest the animal be so irritated that 

 in the extreme flexion of the tarsus which is often caused by 

 bandaging, the wound dressings may be completely deranged. 

 A wide gauze bandage material is most satisfactory; cotton of 

 long fiber is separated in thin layers and wound about the hock, 

 extending from the site of injury to a point about six inches 

 proximal to the summit of the os calcis. By using an abundance 



