Feline fracture repair - is the cost of locking implants scientifically justified ?

Locking implants are commonly used in veterinary medicine nowadays. This is especially true for dogs, but also for cats^1-3. However among veterinarians there seems to be a hesitation utilizing locking implants in cats, mainly due to the higher price of the constructs. The advantages of locking plates compared to conventional plating systems are due to the head of a locking screw securely locking into the plate. This creates a rigid construct without compression of the plate on the bone surface and underlying vasculature is spared ^4,5. Additional beneficial effects are the higher resistance to screw pull-out. This is especially true in thin bone, like the pelvis or mandible ^6,7. Perfect anatomical contouring of the implant is not required and consequently the risk of secondary loss of fracture reduction during screw insertion is limited and minimally invasive fixation techniques are easier and faster to apply ^1,8,9. These principles apply to all species, but cats are special patients after all. Their musculoskeletal system is capable of impressive performances. Also the range of motion of feline joints is greater compared to dogs and this flexibility is important during every day tasks. Most of the cats presented to the hospital with fractures are free roaming and confining these patients post operatively to a small area can be very challenging. Some cats might tolerate these restriction, but a great number of them will rampage. This will not only stress the stability of the fracture repair, but also the owner’s compliance. Unfortunately cats show also a rather high rate of non-unions, especially in the tibia and proximal ulna reaching up to 15-37,5% and 23% respectively. Presence of an open fracture, comminution, older age, higher body weight or concurrent injuries increase the risk for failure of bony fusion and necessity for a revision surgery ^10,11. Despite these facts, the subjective clinical outcome perceived by the owner is very good ^11,12. However objective lameness evaluation in cats is very difficult to obtain. [...]