|
Brian J. Pease, MS, PT, OCS
Orthopaedic Specialist
Physiotherapy
Associates
Shoulder instability has been, until
recently, an under-recognized source of shoulder pain in individuals
involved in repetitive or prolonged overhead activities in the
workplace. Once thought to be unique to young (< 30 years of age)
athletes involved in throwing, swimming, and racquet sports, shoulder
instability is becoming a more frequently recognized factor in shoulder
pain in industry. Despite
the increased incidence of individuals having shoulder pain as a result
of instability, many of these patients continue to be inappropriately
diagnosed and treated for injuries associated with instability rather
than for the primary problem.
Accurate diagnosis of individuals with
shoulder instability begins with recognition of laxity of the
glenohumeral joint. In the
absence of a defined injury, the examiner must invoke clinical tests to
detect the presence of laxity. These
techniques provoke the glenohumeral joint in anterior, posterior, and
inferior directions. The
load and shift test, apprehension test, relocation test, and sulcus sign
are often used for this purpose. Atraumatic
laxity is often present in more than one direction, and occasionally in
both shoulders. In this
case, the instability is more specifically referred to as
multi-directional instability (MDI).
Instability in one direction most often occurs in the anterior or
posterior direction.
If these individuals have inherent laxity
in their shoulders, why do they become symptomatic without a defined
injury? In the presence of
prolonged or repeated movement of the arm that may also include lifting
and holding of tools and other objects, the rotator cuff is required to
make up for the lack of capsular stability.
The result is overuse of the rotator cuff, manifested in symptoms
of increasing pain and inflammation of the rotator cuff and capsule.
It becomes evident when examining the individual with symptomatic
instability that strength and coordination of movement of the shoulder
is diminished. The rotator
cuff and biceps tendon are often inflamed and tender to palpation.
Patients identified with atraumatic
instability have historically responded favorably to conservative care.
Interventions including anti-inflammatory medications, modalities
for pain relief and anti-inflammatory purposes, activity modification,
pain-free strengthening of the rotator cuff and scapular stabilizers,
and functional integration activities are often cited mainstays of
treatment.
Additionally,
taping the involved shoulder to provide stability during the acute and
sub-acute phases of rehabilitation will accelerate movement to the more
aggressive strengthening that precedes returning to pain-free
occupational demands. Application
of tape is performed every 48 to 72 hours during the acute and sub-acute
phases, and the frequency of application is decreased as strength
increase and functional stability increases over time.
Several
interventions that continue to be widely used have questionable roles in
the treatment of patients with atraumatic instability.
Strengthening with elastic bands, while convenient for their
mobility and versatility, often serve to inflame tissues that are
already irritable. Second,
stretching of the shoulder joint beyond comfortable physiological limits
has no place in the treatment of patients with shoulder instability. Finally, the use of non-specific strengthening modalities
such as the UBE in the acute or sub-acute phases of rehab is
inappropriate and possibly injurious.
Individuals
with a traumatic onset of instability are less likely to have a
favorable outcome with conservative intervention because of the
increased prevalence of co-morbid conditions after injury.
Bony pathology to the glenoid (Bankart lesion) or humeral head
(Hill-Sach’s lesion), tears to the glenoid labrum (ie SLAP lesions),
or injuries to the capsule present changes to normal anatomy that may
prevent the restoration of full function.
Surgical intervention to repair the abnormal anatomy and prevent
subsequent episodes of instability may be the best intervention for
these patients. However, in
the presence of normal anatomy and a well conceived rehabilitation
program, many patients are still able to achieve full function after
subluxation or dislocation.
In conclusion,
accurate diagnosis of individuals with shoulder pain and functional
limitations due to glenohumeral instability is an important first step
to successful rehabilitation and return to work.
Patients with normal anatomy should be able to return to full
function within a short period of time if appropriate intervention is
offered. Conservative
management including protection from re-injury, taping, pain-free
strengthening, and anti-inflammatory care are all associated with
successful outcomes. Early
use of elastic bands, non-specific strengthening, or aggressive
stretching have been noted to delay or prevent successful recovery.
Back
to Top
|