Page 96 - Clinical Manual of Small Animal Endosurgery

84 Clinical Manual of Small Animal Endosurgery

Severe restriction within the biceps tendon sheath is suggestive of
spinatus muscle tendonopathy and when this arthroscopic finding is
accompanied by supportive clinical findings and diagnostic imaging find-
ings of spinatus tendonopathy the complex nature of the disease should
be considered when planning treatment. When there is significant com-
promise to the integrity of the biceps tendon tenectomy is recommended.
In some cases of spinatus tendonopathy shoulder pain and lameness
appear to be attributable to the spinatus disease and not to indirect
effects on the biceps tendon. Hence if the functional integrity of the
biceps is not significantly compromised, arthroscopy should be com-
pleted, the biceps tendon should be left intact and the diseased spinatus
tendon should be treated. Clinical reports indicate that spinatus tendo-
nopathy can respond, in some cases, to intra-lesional injection with
methylprednisolone and accompanied by strict rest. Surgical treatment
is required for non-responders to medical treatment and a section of the
spinatus tendon of insertion is excised by traditional surgery.

Arthroscopic treatment of glenohumeral ligament insufficiency

Shoulder pain and chronic forelimb lameness attributed to shoulder
instability have become increasingly recognised following the introduc-
tion of arthroscopy to small veterinary orthopaedics because of the
ability to visualise pathological changes in the support structures within
the shoulder joint. Arthroscopic signs of ‘wear and tear’ are not uncom-
monly observed on shoulder arthroscopy in mature dogs and undoubt-
edly, because arthroscopy remains a relatively new modality, there is a
risk of misinterpretation of the findings of shoulder arthroscopy. This
leads to the potential for overdiagnosis of shoulder instability if arthro-
scopic findings are evaluated in the absence of supportive evidence from
orthopaedic examination (Akerblom and Sjöström, 2007; Cogar et al.,
2008). Increased shoulder abduction has been documented in sedated
dogs affected with medial glenohumeral ligament insufficiency (Cook
et al., 2005a) but the accuracy of the abduction angle test at correctly
identifying dogs with shoulder instability has been subsequently ques-
tioned (Devitt et al., 2007).
The arthroscopic portals for investigating for shoulder instability are
as described above. The medial joint capsule, the medial glenohumeral
ligament and the subscapularis tendons should all be inspected along
their length from their origin or most proximal extent to their insertion
points and a blunt probe should be employed to investigate any signs of
fibrillation or tearing to establish their significance. It can be helpful to
stress the shoulder in abduction to evaluate the mechanical integrity of
the medial support structures. Next, the lateral collateral ligament and
the lateral joint capsule should be evaluated through controlled with-
drawal of the arthroscope while at the same time tilting the scope crani-
ally together with cranial rotation of the light post. Subsequent caudal