| A
common forelimb condition that presents in canine athletes
is medial shoulder instability (MSI). This condition is similar
to a “rotator cuff injury” in people. MSI may
cause subtle signs of performance-related issues such as refusing
tight turns, or may be as severe as a weight-bearing lameness.
The joint capsule, ligaments, and surrounding muscles and
tendons all contribute to the stability of the shoulder. Insult
or injury to any portion of the capsuloligamentous support
structures can potentially cause shoulder joint pathology
resulting in pain and dysfunction. The components that are
most commonly affected by MSI include the joint capsule, medial
glenohumeral ligament (MGL), subscapularis tendon, supraspinatus
tendon, and less commonly, the biceps tendon. Depending on
the severity and chronicity of the instability, the cartilage
may also be affected. Currently,
the exact cause of MSI in dogs is unknown, although it is
suspected to be related to chronic repetitive activity or
overuse. Overuse of the shoulder support structures leads
to degeneration of the tissues and lowering the tensile
strength of the tissues, which predisposes them to fraying,
disruption, and eventually complete breakdown.
Based
on the results of the orthopedic examination, shoulder abduction
angle tests, and arthroscopic scoring, dogs are placed into
one of three categories; mild, moderate, or severe. Dogs
in the mild category typically have shoulder abduction angles
of 30º - 40º and arthroscopic findings consisting
of mild pathology; inflammation without fraying, disruption,
or laxity of the MGL, subscapularis tendon, or joint capsule.
MGL
fraying |
Supraspinatus
bulge |
Dogs
in the moderate category typically have abduction angles
that range from 40º - 65º and arthroscopic findings
consisting of fraying, disruption, and laxity of the MGL
and subscapularis tendon, as well as focal synovial proliferation
associated with the subscapularis tendon, and synovial hypertrophy
or hyperplasia.
Dogs in the severe
category typically have abduction angles greater than 65º
and arthroscopic findings consisting of complete tears of
the MGL and severe disruption and the supscapularis tendon
and joint capsule. For this type of injury, reconstruction
of the medial compartment by direct tissue reapposition
and synthetic capsulorrhaphy by a medial approach may be
indicated.
Radiofrequency
(RF) is the preferred method for thermal capsulorrhapy in
human medicine. In dogs, RF is used for treatment of tendon
and ligament laxity, the joint capsule, and ablation of
pathologic intra-articular structures. Following RF treatment,
inflammation, repair and remodeling occur. Inflammation
is a crucial step in the healing process and therefore,
treatments that decrease inflammation (NSAIDs, LASER therapy,
acupuncture, etc) are not recommended during the initial
postoperative period (approximately 6 weeks). Treated tissue
becomes weaker than pre-treatment levels before it gets
stronger and must be protected for as long as three months.
Following RF treatment, post-operative care includes a custom
shoulder support system / hobbles (www.Dogleggs.com), strict
exercise restrictions, and rehabilitation therapy.
Rehabilitation
Protocol - Post-op MSI
Acute
Stage: (weeks 1-3) It is important to note that
conservative management is critical during this stage of
healing. Exercises are geared towards stabilization of the
shoulder complex to support the healing capsule.
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ALL
exercises done in hobbles except ROM and manual therapy. |
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Ice
therapy 2-3x’s/day for the first 3 days and then
only after home and clinic |
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therapy/exercise
sessions. |
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PROM,
joint compressions to toes, carpus, elbow, joint mobilizations,
and |
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manual
treatment. |
• |
HEP
of lateral raises, torso strengthening, PROM, and cervical
spine stretches |
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3x’s/day. |
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Slow
leash walks may begin. |
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Sub-Acute
Stage: (weeks 4-9): Protection of the healing structures
remains imperative during this stage. Manual treatment remains
important to reduce compensatory effects of hobble use.
Treatments focus on muscular strength, maintaining ligament
or musculotendinous extensibility, beginning ROM in all
directions of shoulder, increasing joint mobility and improvement
of the proprioceptive system. There should be minimal pain,
full weight-bearing, decreased muscle spasm/guarding of
the shoulder complex, full flexion of the shoulder, and
full flexibility of the biceps, triceps and teres major.
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• |
ALL
exercises done in hobbles except ROM and manual therapy. |
• |
Ice
therapy may be done after therapy/exercise sessions. |
• |
Increase
HEP of stabilization exercisesand torso strengthening. |
• |
Increase
leash walks. |
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End-Stage:
(weeks 10-12) Full ROM of shoulder complex, including scapula,
should be present, with no palpable tenderness of biceps,
teres major, pecs and subscapularis. Prepare for return
to normal activities and sports.
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• |
Hobbles
utilized during normal daily activity to prevent forced
abduction of the |
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shoulder. |
• |
Introduction
of weight-bearing exercises without hobbles. Otherwise,
hobble use |
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is
still necessary. |
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Return-to-Sports
Stage: (week 15-16) It is important to note that
this stage can begin if healing time for your patient was
normal and was able to progress to each stage without complication.
Limb circumference/muscle mass should be equal or within
1/2cm of each other. No restrictions with soft tissue structures
and confirmation of full healing from surgeon. Abduction
angles should be considered as well.
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