Cranial cruciate ligament rupture is the most common orthopedic injury in dogs. There are multiple surgical procedures that can be done to treat this disease, but two of the most popular “osteotomy” (cut in the bone) procedures are the TPLO (tibial plateau leveling osteotomy) and TTA (tibial tuberosity advancement).
Both
procedures can provide excellent outcomes and both have their potential complications.
Infection can occur with any surgical procedure, but with orthopedic surgeries
that involve implants, the risk is higher. That is why prior to an elective
orthopedic procedure, the skin is evaluated for infection and antibiotics are
used during the procedure and postoperatively to lessen this risk. If a dog
licks or chews at the incision, this is highly likely to result in an infection
in the immediate postoperative period.
Late infections are also a potential possibility as well, because
urinary tract, skin, oral, or ear infections can spread to the site of an
implant or area of inflammation (osteoarthritis). If the site of an orthopedic
surgery becomes infected, the implants have to be removed to clear that
infection completely. This is because the stainless steel implants do not have
a blood supply and the bacteria stay on the implant in a “biofilm”. The
implants can be removed as long as the bone has healed.
When
we are dealing with removal of TPLO or TTA implants, the level of difficulty
and invasiveness is dramatically different between the two procedures. Below
are radiographs of each procedure showing the metal implants. The TTA implants
involve a cage (square) that acts as a spacer, and during healing bone grows
into this cage. There is also a fork plate and screws that hold the osteotomy
in place. When removing TTA implants, the fork plate and screws easily can be
removed, but the cage must be “cut” out of the bone, leaving a large defect
that has a high risk of fracture. This surgery to remove the cage that is
encased in bone is invasive and difficult. The TPLO, on the other hand, doesn’t
have a cage and only has a plate and screws, which can easily be removed
because the bone doesn’t grow into them.
TTA
radiographs showing cage, fork plate/screws |
TTA
radiographs showing cage, fork plate/screws |
So, when discussing the surgical
options for a cranial cruciate ligament rupture, all the potential
complications need to be discussed and the risks weighed. Infection risk is low
at 7.4% (Gallagher
AD et al. Implant removal rate from infection after TPLO in dogs. Vet Surg.
2012), but
if it is your dog that needs the implants removed, the process is less
complicated to have had a TPLO over the TTA!
TPLO radiographs
showing plate/screws |
TPLO radiographs showing plate/screws |