Diagnosis and Management of Orthopaedic Infection after Stifle Surgery 325procedures (Nazaraliet al. 2015). These rates
seem to be fairly similar to most high tibial
osteotomy procedures.
Although much less has been published on
the other procedures, infection rates after tibial
tuberosity advancement (TTA) are very similar,
and rates between 2.6% and 12.5% have been
reported (Lafaveret al. 2007; Wolfet al. 2012;
Dal-bo ́et al. 2013; Proot & Corr 2013; Yapet al.
2015). Significantly higher infection rates have
been observed in a population of Boxer dogs
compared to non-Boxer dogs (22% versus 3.7%),
but the reasons remain unclear (de Lima Dantas
etal. 2015). Closing cranial wedge ostectomy has
published infection rates of between 8.3% and
16.6% (Corr & Brown 2007; Dal-bo ́et al. 2013).
Besides the treatment of cruciate ligament rup-
ture, reported infection rates after patellar lux-
ation repair range from 6.4% to 10% (Gibbons
et al. 2006; Clerfondet al. 2014; Kalffet al. 2014;
Shaveret al. 2014).
Extracapsular techniques for cruciate liga-
ment stabilization have generally been associ-
ated with a lesser risk of infection. The largest
series of 363 cases of lateral fabellar suture
stabilization reports an infection rate of 3.9%
(Casale & McCarthy 2009). Only infections con-
firmed by a positive culture were counted.
Therefore, this number is likely an underestima-
tion of the true infection rate. An additional 5%
of the cases were treated with empirical antibi-
otics without definitive diagnosis (Casale &
McCarthy 2009). This number is similar to the
infection rate of 4.2% in another study (Freyetal.
2010). Extracapsular techniques using braided
polyester sutures appear to have similar infec-
tion rates (Cooket al. 2010; Raske & Hulse
2013), though insufficient evidence has been
published to allow any conclusion at this time.
Pathogens
Coagulase-positiveStaphylococcusspp. such as
S. pseudintermediusandS. aureusare responsi-
ble for the majority of infections, while other
bacteria such asStreptococcusspp.,Enterococ-
cusspp.,Escherichia coliandPseudomonas aerug-
inosaand others are encountered with less fre-
quency (Fitzpatrick & Solano 2010; Thompson
et al. 2011; Gallagher & Mertens 2012; Dal-bo ́
et al. 2013; Etteret al. 2013; Savickyet al. 2013;
Nazarali et al. 2015; Yap et al. 2015). The
increased incidence of infection caused by
multi-drug-resistant (MDR) bacteria is of par-
ticular concern for both human and veterinary
surgery, as the treatment of these infections is
particularly challenging. In stifle surgery, the
proportion of infections caused by an MDR bac-
teria range between 10% and 58% (Fitzpatrick &
Solano 2010; Gallagher & Mertens 2012; Etter
et al. 2013; Savickyet al. 2013; Yapet al. 2015).
In a multi-center study, 38% of TPLO infec-
tions were caused by a MDR bacterium. Staphy-
lococci were particularly prone to show drug
resistance, with up to 60% ofS. pseudintermedius
and 50% ofS. aureusbeing methicillin-resistant
(Nazaraliet al. 2015).
Risk factors predisposing patients to infec-
tion after stifle surgery are multiple and, for
the most part, similar to the risk factors in
other surgeries: Wound classification, type of
procedure, American Society of Anesthesiolo-
gists (ASA) score, obesity, gender and neuter-
ing status, endocrinopathies, duration of anes-
thesia or surgery, number of people in the
operating theater, use of skin staples, timing
of clipping, and so forth have all been associ-
ated with an increased risk of infection (Beal
et al. 2000; Nicholsonet al. 2002; Eugsteret al.
2004; Fitzpatrick & Solano 2010; Freyet al. 2010;
Yapet al. 2015). Risks factors for methicillin-
resistantS. pseudintermedius(MRSP) infections
after TPLO surgery include being an MRSP car-
rier and being a Bulldog (Nazarelliet al. 2015).
The postoperative, prophylactic use of antibi-
otics is a highly debated subject in both human
and veterinary surgery. Routine postoperative
antibiotic treatment beyond 24 hours is not rec-
ommended in people undergoing clean surgi-
cal procedures as this practice has not been
shown to reduce SSI rates and may contribute
to the development of antimicrobial resistance
and additional morbidity (Mangramet al. 1999;
Bratzler & Houck 2005). However, several
recent veterinary studies do suggest a benefit
of administering postoperative antibiotics after
cruciate ligament rupture surgery, in particular
after TPLO (Fitzpatrick & Solano 2010; Freyet al.
2010; Gatineauet al. 2011; Nazaraliet al. 2015). In
those studies, the administration of antibiotics
for 3 to 14 days had a significant protective effect
against infections. The duration of antibiotic
prophylaxis required is unknown, and none of