“Moe” was a 3 yr old male Afghan hound with a history of fighting with other dogs - He presented acutely lame on one of the pelvic limbs and was brought to the clinic directly - The stifle joint was unstable on palpation with no evidence of crepitus - Swelling was minimal - Radiographs were ordered and two conventional views were made of the stifle joint - (hint - the radiographic technician had always been instructed to position the limb in an anatomical position when radiographing an extremital joint).The images are presented twice with a difference in contrast permitting better evaluation of the soft tissues. Radiographic diagnosis - No fracture lines or avulsion fragments were noted on the conventional views - The femoropatellar joint was thought normal - Alignment of the two major bones was thought to be normal except for a suspect increase in width of the joint space in the femorotibial joint laterally (arrows) - The minimal decrease in the size of the infrapatellar fat pad cranially suggests a possible tearing of the joint capsule with joint fluid escaping into the periarticular tissues - The shadow outlining the caudal border of the joint capsule is further caudal than normal (arrow) - These abnormal findings suggest a possible meniscal and/or ligamentous injury - Studies made under stress were requested. Radiographs made under stress are shown when compared with the earlier study and clearly demonstrate the severity of the soft tissue injury with tearing of the CrCL as well as the lateral collateral ligament - Meniscal injury plus other soft tissue injury is suspected as well. It is probably safest to make the standard radiographic study with the limbs in a neutral positioning until the severity of the trauma is better understood - The degree of soft tissue injury could be estimated on physical examination, but again, physical manipulation of the joint could cause additional injury to an unsuspected fracture site - Once the absence of fractures is determined on the non-stress studies, stress can be applied to the joint and the second radiographic study made that clearly shows the extent of the soft tissue injury - Stress can be applied in any direction to reflect abnormal flexion or extension, lateral or medial angulation, or rotational abnormality.
