Case of the week 12.10.18
Publication Date: 2018-12-09
History
3 year old male castrated cat. Non-ambulatory after chasing chipmunk
3 images
Findings
Orthogonal radiographs and stress view of the left stifle are available for interpretation.
Most noted on the lateral view there is subluxation of the tibia cranially in regards to the distal femur. There is minimal intracapsular effusion. There is bowing of the proximal tibia and distal femur in opposite direction on all the cranio-caudal projections available. However, the patella is in situ on all the available radiographs.
On the stressed cranio-caudal projection there is mild widening of the medial aspect of the stifle joint with concurrent narrowing of the lateral aspect.
Diagnosis
Changes most consistent with deranged stifle
The bowing of the tibia and femur may indicate underlying chronic patellar instability.
Discussion
While cranial cruciate ligament injury is by far the most common injury in the canine stifle, injury to the caudal cruciate is infrequently observed as well. Caudal cruciate ligament rupture (CaCLR) may occur as an isolated problem or in conjunction with other soft tissue injuries of the stifle joint. If other injuries are present (such as collateral ligament injuries, injuries to the menisci and the cranial cruciate ligament termed ‘deranged stifle’) instability is generally easily palpable and severed. Isolated CaCLR is frequently misdiagnosed as caudal cruciate ligament disease (CCLD)`1 since it can be difficult to differentiate cranial from caudal drawer. Definitive diagnosis can be established with stress radiographs, MRI, CT or arthroscopy/surgical exploration of the stifle. However, since treatment for CaCLR is frequently non-surgical it is advisable to use imaging modalities for the diagnosis. Stress radiographs can be performed by placing caudal stress on the tibia while taking a standard lateral radiograph. Caudal tibial displacement is diagnostic for CaCLR.
http://www.fecava2016.org/proceedings/21_Orthopedic_Surgery.pdf
Surgical stabilization of the knee was performed in this patient.
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