202 Surgical Treatment
success rate of only 75% at one year after
TPLO treatment. Although outcomes seem to be
optimal for current procedures in many studies,
the limitations mentioned above and the pro-
gression of more sensitive outcome measures
may change the interpretations of results.
One consistent finding between many stud-
ies is that most dogs will still have progres-
sive osteoarthritis (OA) after surgical treatment,
affecting long-term success (Elkinset al. 1991;
Innes & Barr 1998; Lazaret al. 2005). Further-
more, although the severity of OA has not
been shown to be correlated with lameness,
dogs with OA have a greater chance of lame-
ness compared to a dog with a normal stifle
(Gordonet al. 2003). It is hypothesized that pro-
gressive OA develops because the most com-
monly performed techniques do not replace all
mechanical properties of an intact cranial cru-
ciate ligament (CrCL) (Kimet al. 2012; Skin-
neret al. 2013; Biskupet al. 2014a). The CrCL
is known to prevent cranial translation, inter-
nal rotation, and hyperextension of the tibia
(Heffron & Campbell 1978).
An in-depth discussion of all current repair
options is beyond the scope of this chapter,
but main concepts will be briefly discussed.
First, extra-articular sutures lack the material
strength to eliminate drawer (Cabanoet al. 2011;
Roseet al. 2012; Biskupet al. 2014a), and the
anchor points are not likely to be isometric
(Roeet al. 2008; Fischeret al. 2010; Hulseet al.
2010b). The results of some studies that incor-
porated objective outcomes also suggest that
suture repairs are inferior to tibial osteotomies
(Gordon-Evans et al. 2013; Krotscheck et al.
2016). Similarly, tibial osteotomies have a
limited ability to prevent internal rotation,
and femoral-tibial subluxation is inconsistently
eliminated (Kimet al. 2012; Skinneret al. 2013).
Continued instability after these repairs likely
contributes to a higher rate of latent meniscal
tears and progressive OA that is demonstrated
when follow-up is extended to a year or longer
(Bennettet al. 1988; Elkinset al. 1991; Rayward
et al. 2004; Kowaleskiet al. 2005; Staufferet al.
2006). Thus, is it not surprising that the veteri-
nary surgical community has not agreed upon
the ideal surgical treatment for CR.
The ‘gold standard’ in humans for anterior
cruciate ligament (ACL) rupture repair is intra-
articular placement of a graft at the attach-
ment sites of the ACL. Currently, there is no
consensus on the ideal graft, nor on the method
of fixation (Murray 2009). ACL graft repairs in
human patients have a reoperation rate of 3–5%,
and<20% of patients develop progressive OA
(Harilainen & Sandelin 2009). In contrast, up to
30% of dogs have postoperative meniscal injury
with complete CR, and close to 100% have pro-
gressive OA at 2 years after treatment (Lazar
et al. 2005; Hulseet al. 2010a; DeLukeet al. 2012).
Differences in pathophysiology, function, and
the ability of human patients to assess their own
outcome may explain some of these differences,
although a fivefold difference in treatment fail-
ures might suggest that the anatomic recon-
struction procedures performed in people are
superior to the non-anatomic procedures com-
monly used in dogs.Historical use of intra-articular repairs
Although the ACL was first mentioned in
records dated from 3000 BC, its complex
anatomy was first described by Claudis Galen
between 300 and 400 BC. Although many repair
methods were attempted, the first modern case
series reporting an intra-articular repair was
reported by Hey Groves in 1917 (Davarinos
et al. 2014). Groves described a fascia lata strip
placed through the joint and anchored in a
tibial tunnel; this procedure is the predeces-
sor to current repairs in humans. A modifica-
tion of this technique led to the first veteri-
nary intra-articular repair. In 1952, Paatsama
described passing the lateral fascia lata through
bone tunnels in the femur and tibia and sutur-
ing it to soft tissue as the graft exited the
tunnel (Knecht 1976; Burnett & Fowler 1985).
The original repair has gone through multiple
modifications, including those by Singleton in
1957, Titemeyer and Brinker in 1958 and Rudy
in 1974, leading to the intra-articular repairs
most familiar to veterinarians, the ‘over-the-
top’ and ’under-and-over’ techniques (Single-
ton 1957; Knecht 1976; Hulseet al. 1980; Shires
et al. 1984). As recently as 20–30 years ago,
intra-articular reconstructive techniques were
the preferred CrCL repair methods in dogs, and
have also been reported in cats (Korvicket al.
1994; Moore & Read 1995; Inneset al. 2000b;
Garcia et al. 2012). Although the outcomes
were subjective, some results were promising
(Pichleret al. 1982; Denny & Barr 1987; Innes &