Case Study

CT Degenerative Joint Disease of the Stifle and Vertebral Malformation in a 4 year old MN French Bulldog

History of cruciate ligament injury

Image Interpretation

CT of the left stifle region, chest and abdomen: The scan covers for the left stifle joint area only in the periphery and does not include the stifle joint entirely. There was mild stifle joint effusion, mild new bone formation at the periarticular margins of the femorotibial joint, moderate smooth new bone formation at the periarticular margins of the femoropatellar joint. The femoral condyles revealed pronounced caudal bending (walking stick deformation). There was a cartilaginous remnant after disturbed enchondral ossification in the proximal aspect of the former apophyseal physis of the tibial tuberosity which is a frequent incidental finding in Bulldogs. Mild cranial thrust of the tibia was noted. The cranial and caudal cruciate ligament and menisci were not detectable (requires intraarticular contrast). Both hip joints showed mild signs of dysplasia and mild osteophyte formations.

There were congenital malformations of the mid thoracic and caudal vertebrae. T8 was a ventral and
right sided wedge shaped hemivertebra which led to mild mid thoracic kyphosis and lordosis. The
caudal spine was stunted and bent due to wedge shaped hemivertebrae. Both sites are typical
manifestations of spinal malformations in Bulldogs and commonly are clinically silent.
The lumbosacral intervertebral disc showed a mild dorsal protrusion reducing the epidural fat space
ventral to the Cauda equina nerve fibres whilst the dorsal epidural space was maintained.
A symmetrical well delineated formation of mineral-attenuating disc material was seen occupying the
ventral epidural space level with the intervertebral disc space C3/4. The extruded material extended
from the mid body of C3 cranially to the cranial third of C4 caudally. 30% of the vertebral canal
diameter were occupied at maximum. There was mild dorsal deviation and compression of the dural
tube. Multiple intervertebral discs showed mineralization. Pronounced spondylosis deformans and moderate disc space collapse were seen level with L5/6.

DX

The findings of the left stifle joint are compatible with mild degenerative joint disease of the femorotibial and moderate degenerative joint disease of the femoropatellar joint and are typical manifestations in cranial cruciate pathology or patellar luxation. Moreover a congenital malformation of the distal femur and developmental abnormality of the tibial tuberosity physis were noted. Both of which are breed associated findings that are usually incidental but may influence the surgical approach. There was a chronic disc extrusion at the C3/4 intervertebral disc space with disc migration and mild compressive myelopathy. This is an old process which may be clinically silent or be associated with periodic reoccurrence of clinical signs. There was mild degenerative lumbosacral stenosis with lumbosacral disc protrusion and Spondylosis L5/6 – no Cauda equina compression was seen. Likely of no current relevance. There were congenital malformations leading to kyphosis and lordosis of the spine. There was generalized chondroid intervertebral disc degeneration. There was mid bilateral hip dysplasia and coxarthrosis.

Outcome

The assessment of the stifle joint is limited to the quality of the image set. Ideally the scan should be repeated with the leg in the image center, stifle joint extended and intraarticular contrast
administration (in case articular soft tissue structures are to be assessed).