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Two week duration of right hindlimb lameness. Dog was left unattended in an ex-pen and when the owner returned, the puppy had escaped the pen and was non-weight bearing on the right hind leg. Despite activity restriction, still grade II/V right hindlimb lameness with marked stifle instability. Radiographs show marked effusion without evidence of fracture or bony abnormality.

TECHNICAL FACTORS

MRI images of the right stifle joint are available for review and include T1-weighted, 3D T2-weighted with and without fat saturation, 3D PD-weighted images.

T1w sagittal, right stifle

T2 SPC sagittal, right stifle

PD sagittal

T1w transverse

T2w transverse

PD transverse

3D T2w DESS, dorsal reconstruction

Moderate joint distension is noted. Two large, mildly caudally displaced fractures of the caudoventral articular margin of the distal femoral medial condyle are present. A wide, communicating fissure extends from a fracture segment cranially along the subchondral bone deep to the site of origination of the cruciate ligaments within the intercondylar fossa. The cruciate ligaments are intact without evidence fiber disruption, and the menisci, patellar tendon, long digital extensor tendon, and collateral ligaments are intact. The remainder of the study is unremarkable.

CONCLUSIONS

Traumatic distal right femoral medial condylar articular fracture with extension along the subchondral bone of the intercondylar fossa. While the cruciate ligaments are intact, the fracture involves their origination site and therefore related instability is assumed.

DISCUSSION

Winston was bred for competitive lure coursing and the owner desired the patient to compete in the future. At the time of initial radiographs and the MRI study, the patient’s injury was approximately two weeks old.

The surgeon was concerned about either a cranial and/or caudal cruciate ligament rupture (described as “sloppy” upon manipulation) of the right stifle joint.

After MRI evaluation, the patient underwent internal surgical reduction of the medial condylar fractures. Post-operative physical therapy was performed and, at the patient’s 7-week follow up appointment, the owner noted the patient would occasionally lift the right leg and limp but was mostly sound while leash walking. On examination at this follow up appointment, the patient was 0-I/V lame at a walk and would slightly shift weight off the right pelvic limb when standing. Mild muscle atrophy of the right hind leg was noted. The right stifle had normal range of motion with mild joint effusion. No crepitus was appreciated. A 2 mm caudal drawer was noted but the stifle was stable on tibial thrust. Due to persistent femoral muscle atrophy, pin removal was discussed but ultimately not performed.

On recent phone follow up with the owner, the patient is reportedly sound and starting training for competitive lure coursing.