Tibial Plateau Leveling Osteotomy 221during bone healing and radiographic
osteotomy stability showed no difference
between non-locking and locking plates
(Krotschecket al. 2012), while a similar prospec-
tive study concluded that locking screw fixation
increases the stabilization of TPA during heal-
ing and provides improved radiographic
evidence of osteotomy healing (Conklinget al.
2010). The use of a locking plate construct
is also associated with a lower incidence of
infection and a lower general complication rate
(Kowaleskiet al. 2013; Solanoet al. 2015).
Concerns related to the use of the original
Slocum TPLO plate center around plate corro-
sionin vivowith the subsequent generation of
chemical species that have the potential to cause
disease, the presence of plate magnetism, and
findings showing the plate to be a cast stain-
less steel implant (Boudrieauet al. 2006; Charles
& Ness 2006). Furthermore, Slocum TPLO
implant-associated sarcoma has been reported
(Boudrieauet al. 2005). Metallurgical analysis of
alternative TPLO implants by an independent,
unbiased party is currently lacking.
Complications after TPLO
The overall postoperative complication rate of
TPLO has been reported to vary from 7.2%
to 28% (Pacchianaet al. 2003; Priddy et al.
2003; Staufferet al. 2006; Fitzpatrick & Solano
2010; Gatineauet al. 2011; Oxleyet al. 2013;
Coletti et al. 2014). Factors associated with
the development of complications include tib-
ial plateau angle> 30 ◦, increased body weight,
and complete versus partial CR (Fitzpatrick
& Solano 2010; Colettiet al. 2014). A higher
complication rate has also been reported in
dogs undergoing simultaneous bilateral TPLO
(Priddyet al. 2003). Notably, most complica-
tions can be resolved without surgical interven-
tion (Pacchianaet al. 2003). Examples of compli-
cations include hemorrhage, poor incision site
healing, patellar tendon enlargement, fractures
involving the fibula or tibia, subsequent menis-
cal injury, implant failures and infection.
Infection rates for TPLO average around
4.6% (Bergh & Peirone 2012), which is higher
than expected for a clean surgical proce-
dure. Theoretically, postoperative administra-
tion of antimicrobials is not indicated for clean
surgeries, but numerous studies have shown
that postoperative antibiotic therapy does pro-
vide a protective affect against surgical site
infection in TPLO (Fitzpatrick & Solano 2010;
Freyet al. 2010; Nazaraliet al. 2014; Nazarali
et al. 2015; Solanoet al. 2015). If treated appro-
priately, no association is seen between surgical
site infection and long-term functional outcome
(Brownet al. 2016).
Dogs with a preoperative TPA≥ 35 ◦ have
a higher incidence of postoperative compli-
cations, with a loss of postoperative TPA or
‘rockback’ during the convalescent period being
the most common. The addition of ancillary
implants to TPLO significantly reduces the inci-
dence of this problem (Duerret al. 2008). Acom-
bination of TPLO with a closing cranial wedge
ostectomy has been suggested as one possi-
ble means of addressing excessive TPA (Talaat
et al. 2006). Small losses of postoperative TPA of
about 1.5◦during the convalescent period have
been documented in the face of apparently sta-
ble implant fixation, and by themselves do not
appear to have any deleterious effects on clin-
ical outcome (Moelleret al. 2006; Hurleyet al.
2007).
Radiographic evidence of patellar tendon
enlargement is a common finding after TPLO,
with up to 80% of clinical cases showing evi-
dence of moderate to severe thickening at
2 months postoperatively (Careyet al. 2005)
(Figure 27.4). Despite this finding, only 7%
of the dogs in this study displayed clinical
signs of patellar tendinosis, with most dogs
improving with medical management. Patel-
lar femoral joint kinematics are altered by
TPLO, and this may be a predisposing factor
to patellar tendinosis (Pozziet al. 2013). Patella
fracture after TPLO is a rare complication
(0.25–2%) that has been associated with radio-
graphic evidence of patellar tendon thickening
(Pacchianaet al. 2003; Careyet al. 2005; Gatineau
et al. 2011; Rutherfordet al. 2014). Non-surgical
management generally provides a satisfactory
outcome.
Dogs that are cranial tibial thrust-negative
immediately after surgery occasionally become
thrust-positive after surgery. Affected dogs
often have poor limb function and pivot shift on
ambulation. Pivot shift is created by a combina-
tion of cranial translation of the tibia with inter-
nal rotation of the stifle. The mechanism for this