Few studies have evaluated the relationship between patients’
pre-operative expectations and the outcome of orthopaedic procedures.
Our aim was to determine the effect of expectations on the outcome
after primary anatomical total shoulder arthroplasty (TSA). We hypothesised
that patients with greater expectations would have better outcomes. Patients undergoing primary anatomical TSA completed the Hospital
for Special Surgery’s Shoulder Expectations Survey pre-operatively.
The American Shoulder and Elbow Surgeons (ASES), Shoulder Activity
Scale (SAS), Short-Form-36 (SF-36), and visual analogue scale (VAS)
for pain, fatigue, and general health scores were also collected
pre-operatively and two years post-operatively. Pearson correlations
were used to assess the relationship between the number of expectations
and the outcomes. Differences in outcomes between those with higher
and lower levels of expectations for each expectation were assessed
by independent samples Aims
Patients and Methods
Reverse total shoulder replacement (RTSR) depends
on adequate deltoid function for a successful outcome. However, the
anterior deltoid and/or axillary nerve may be damaged due to prior
procedures or injury. The purpose of this study was to determine
the compensatory muscle forces required for scapular plane elevation
following RTSR when the anterior deltoid is deficient. The soft
tissues were removed from six cadaver shoulders, except for tendon
attachments. After implantation of the RTSR, the shoulders were
mounted on a custom-made shoulder simulator to determine the mean
force in each muscle required to achieve 30° and 60° of scapular
plane elevation. Two conditions were tested: 1) Control with an
absent supraspinatus and infraspinatus; and 2) Control with anterior
deltoid deficiency. Anterior deltoid deficiency resulted in a mean
increase of 195% in subscapularis force at 30° when compared with
the control (p = 0.02). At 60°, the subscapularis force increased
a mean of 82% (p <
0.001) and the middle deltoid force increased
a mean of 26% (p = 0.04). Scapular plane elevation may still be possible following an RTSR
in the setting of anterior deltoid deficiency. When the anterior
deltoid is deficient, there is a compensatory increase in the force
required by the subscapularis and middle deltoid. Attempts to preserve
the subscapularis, if present, might maximise post-operative function.
