Page 420 - Canine Lameness

392 22 Neoplastic Conditions of the Pelvic Limb

22.2.3 Stifle Region
Osteosarcoma is frequently diagnosed in the distal femur and proximal tibia (Figure 22.1). While
osteosarcoma may occur independently, there is an ongoing discussion about a possible association
with Tibial Plateau Leveling Osteotomy (TPLO) surgery. Explanations for this possible association
include corrosion of the bone plate or local infection leading to an altered local cellular activity
(Selmic et al. 2018). Implants that are not meeting the current regulatory standards (such as cast
TPLO plates which are not sold anymore) are associated with an increased metal ion release when

(A) (B) (E)

(C) (D) (F)

Figure 22.1 Radiographs of stifle joint neoplasia associated with (A, B) proximal tibial osteosarcoma, (C, D)
histocytic sarcoma, and (E, F) distal femoral osteosarcoma: (A) lateral and (B) craniocaudal radiographs of a
dog that developed osteosarcoma of the proximal tibia after Tibial Plateau Leveling Osteotomy (TPLO).
Note the enlarged popliteal lymph node (red arrow); (C) lateral and (D) craniocaudal radiographs of the
stifle joint with histiocytic sarcoma and an enlarged popliteal lymph node (red arrow). Note the severe soft
tissue opacity in the stifle joint and subtle lysis of the proximal tibia, fibula, and intercondylar fossa of the
femur (white arrows); (E) lateral radiograph at time of initial presentation and at (F) follow-up showing
progression of the osteolytic and proliferative changes classic for distal femoral osteosarcoma.