Gabby
Case Submitted by:
Ann L. Johnson DVM, MS, Diplomate ACVS
"Gabby" is a 2 .5 year old intact male cat. He was found with a non-weight bearing lameness of the right rear limb. There is a palpable fracture of the right femur. Although this is a barn cat, the owners really like him and are willing to do anything necessary, including keeping him in the house, to treat the fracture.
Is the articular surface of the coxofemoral joint affected?
Yes. There appears to be a fracture of the acetabulum visible on the lateral radiographic view of the femur and pelvis. The fracture appears incomplete on the reconstructed CT view of the medial surface of the acetabulum. Alternatively this may be an older fracture which is beginning to heal, although there is no documentation of previous trauma.
Is the greater trochanter fractured?
Yes. The greater trochanter is fractured. This is suggested on the radiograph and confirmed with the reconstructed CT.
Is the femoral neck fractured?
No. The femoral neck is intact based on the reconstructed CT.
Is anatomic reconstruction the appropriate method for reducing the femoral fracture?
No. Because of the multiple comminuted fragments, anatomic reconstruction is probably not possible and the surgical trauma to surrounding soft tissue required to attempt anatomic reconstruction will be detrimental to fracture healing. Fractures which are considered non-reducible, ie the bone column cannot be reconstructed to help resist the load of weight-bearing, are better treated with biologic fixation concepts. The principles of biological fracture fixation include minimal disruption of soft tissues at the comminuted fracture site. For fractures of the radius and tibia, this is accomplished by using closed reduction and an external fixator. Comminuted fractures of the femur and humerus are not as easily manipulated, and not as well suited for external fixation. When internal implants are chosen as the method of fixation, an open but don't disturb the fragments philosophy is used in the surgical approach. A standard approach is used to expose the major segments of the bone. The bone is distracted to length and a precontoured plate functioning as a buttress plate is applied. The fracture fragments are not disturbed.
Which implant system would most likely be a successful method of stabilizing this fracture?
Bone plate and screws. The fracture is considered non-reducible therefore reconstruction with cerclage wire is inappropriate. Additionally, with the comminution around the proximal femur and the fracture through the greater trochanter, it would be difficult to place an intramedullary pin . The proximal comminution also makes placing proximal interlocking nail screws impossible. It would similarly be difficult to place the proximal pins of the external fixator. The most appropriate way to stabilize this fracture is to use a plate as a buttressing plate by placing screws in the greater trochanter and large neck fragment while bridging the remainder of the fragments. One lag screw was used to secure two fragments. The wire was used to bring additional fragments into the general fracture area. It may be more appropriate to use resorbable suture for this purpose.
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Outcome:
By 12 weeks after surgery the proximal femoral cortex had healed and was remodeling. There is lucency around the proximal screw and the greater trochanter appears to be secured only by a fibrous union. Clinically the cat was fully weightbearing at this time and also at 20 weeks after surgery. The implants will not be removed unless they cause clinical problems.
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