Advances in the Canine Cranial Cruciate Ligament, 2nd edition

308 Surgical Treatment

(A) (B)

Figure 37.1 Arthroscopic views of

medial femoral condyles in stifle

joints with cranial cruciate ligament

rupture. Note the cartilage

pathology present in both these

stifles. (A) Cartilage damage can

result in minor fibrillation that does

not result in full-thickness loss.

(B) However, in severe cases,

cartilage loss can extend to the

subchondral bone. The white arrows

highlight cartilage fibrillation.

Osteoarthritis precedes stifle

instability associated with cruciate
ligament rupture

Some of the most pivotal findings identified
while investigating the association between
development of OA and its relationship to CR
have come from studies of contralateral sta-
ble stifles of dogs with unilateral complete
CR. Given that the risk of contralateral CR is
between 40% and 60% within 18 months of CR
diagnosis (Doverspikeet al. 1993; de Bruinet al.
2007), use of the contralateral stable stifle in
dogs with unilateral stifle instability is advanta-
geous in providing a model to study the natural
history of CR disease progression.
Based on results of investigations of clini-
cally stable contralateral stifles in dogs with
unilateral CR, it has been established that radio-
graphically detectable OA precedes CR (Dover-
spikeet al. 1993; de Bruinet al. 2007; Bleedorn
et al. 2011; Chuanget al. 2014). This observation
has led to investigations into the use of radio-
graphic OA as a means of prediction of com-
plete CR risk in stifles with partial CR (see also
Chapter 22). Indeed, in contralateral stable sti-
fles of dogs with unilateral CR, both the pro-
gression of OA over time (Inneset al. 2004; de
Bruinet al. 2007) and the degree of OA at the
time of diagnosis (Chuanget al. 2014) (see Chap-
ter 22; Figures 22.2 and 22.3) are predictive of
risk of contralateral CR.
Interestingly, the presence of radiographi-
cally detectable OA in a contralateral stable sti-
fle does not inevitability lead to complete CR,
highlighting that there is incomplete under-
standing of the initiating factors that result in
OA and cruciate ligament fiber rupture, and

the factors associated with progression of dis-

ease within affected stifle joints. However, one

important clue derives from studies showing

that arthroscopically assessed synovitis and

radiographic arthritis are correlated in both

unstable and contralateral stifle joints of dogs

with naturally occurring CR (Bleedornet al.

2011), suggesting that synovitis is a key feature

of early disease. Ultimately, further studies are

required to understand the natural history of

CR. For further information regarding the role

of synovitis in cruciate ligament rupture pathol-

ogy, see Chapter 12.

Progression of osteoarthritis after stifle

stabilization procedures

It is now well established that OA progresses

in the face of stifle stabilization procedures.

Numerous studies have documented this pro-

gression (Table 37.1). Currently there is no

standardized method by which radiographic

OA is quantified in the stifle joint. In the

reported literature, methods for measurement

of radiographic OA, times to follow up evalu-

ation, and use of meniscal release concurrently

with stabilization, are highly variable between

studies.

Cause of osteoarthritis progression after

stifle stabilization procedures

The cause of OA progression after stifle stabi-

lization surgery is likely multifactorial. Theo-

ries presented within the literature include con-

tinued stifle instability and altered joint contact