Page 102 - Clinical Manual of Small Animal Endosurgery

90 Clinical Manual of Small Animal Endosurgery

using a blunt probe. In most cases of cranial cruciate ligament disease
grossly abnormal degenerative change, fibrillation, tearing and haemor-
rhage of the ligament are readily visible. Occasionally, in early disease,
degeneration of the ligament may be appreciated only by careful probing,
which identifies hidden torn fibres, or laxity of components of the liga-
ment associated with fibrillation. Once a diagnosis of cranial cruciate
ligament disease is made, if the lameness is not responsive to medical
treatment, then surgical intervention, including removal of the degener-
ate ligament, meniscal surgery as required and a stifle-stabilisation pro-
cedure, are recommended to accelerate resolution of pain and lameness.
The degenerate cranial cruciate ligament is debrided proximally and
distally using a motorised shaver with a soft-tissue shaving tip, with the
shaver in oscillating mode or using a radiofrequency probe (Fig. 3.14b),
taking care to avoid excessive heating of the articular space. Care should
be taken to avoid iatrogenic damage to the caudal cruciate ligament
proximally and to the intermeniscal ligaments distally. Whereas cruciate
ligament remnants are likely to remain, their role in promoting inflam-
mation in the joint is no longer considered relevant.
Following removal of the cranial cruciate ligament, visualisation of the
menisci is more readily achieved. The medial meniscus is inspected before
the lateral meniscus since substantial lesions to the medial meniscus
occur in association with cranial cruciate ligament injury and these are
clinically significant. With the arthroscope tip in the intercondylar notch,
the stifle is maintained in approximately 30° of flexion. The axial edge
of the medial femoral condyle is followed towards the articular surface
of the medial femoral condyle. The caudal pole of the medial meniscus
is brought into view by controlled insertion of the arthroscope while
maintaining the light post directed axially (at 3 o’clock for the right stifle
and 9 o’clock for the left stifle) and the arthroscope is tilted laterally. A
normal medial meniscus is pale and smooth, has a fine, smooth axial
edge and there is a regular concavity to the upper surface. Fibrillation,
roughening of the surface or presence of a thickened axial edge of menis-
cal tissue are all indicators of a probable meniscal tear (Fig. 3.18). A
blunt probe is introduced through the medial portal and the functional
integrity of the meniscus is assessed (Fig. 3.19). When a tear is present,
the probe is used in tandem with careful visual inspection to evaluate its
shape and type, since this influences the technique required for successful
removal of the torn meniscal portion.
The most common substantial and significant meniscal injury that
causes lameness and pain is the longitudinal vertical tear or ‘bucket
handle tear’, in which a caudo-axial portion of the meniscus is crushed
and torn such that a mid-body tear propagates in the substance of the
meniscus. In the cranial cruciate-deficient stifle, continual and repeated
subluxation of the tibia during the stance phase of gait pinches the medial
meniscus. This creates the tear and pushes the torn portion of meniscus
cranially. Continued crushing and tearing can fully sever the caudal
attachment of the torn meniscal fragment, creating a large free meniscal