A recent article, Thresholds For Diminishing Returns In Postoperative Range Of Motion After Total Shoulder Arthroplasty, pointed out that satisfaction after shoulder arthroplasty - can be associated with scores on patient-reported outcome measures (PROMs). (See Patient satisfaction after shoulder arthroplasty - anticipation and informing). In turn, PROMs are dependent upon restoring lost shoulder range of motion (ROM). The authors questioned whether there was a threshold in postoperative active ROM beyond which additional improvement in motion was not associated with additional improvement in the PROMs that primarily measured function (Simple Shoulder Test [SST], American Shoulder and Elbow Surgeons [ASES] score, and the Shoulder Pain and Disability Index [SPADI]). (Of note, other outcome measures, such as the Shoulder Arthroplasty Smart Score, primarily measure motion (70% of the total score) attributing only 10% of the points to function).
They included 4,459 TSAs (1,802 aTSAs, 2,657 rTSAs) with minimum 2-year follow-up. Indeed they found thresholds in postoperative ROM that were associated with no further improvement in the standard PROMs.
The "S" shapes of these curves are interesting. See for example the figures below plotting the patient's Simple Shoulder Test (SST) responses against active flexion and active external rotation.
At the left side of these curves, improvement in motion has little effect on the number of SST functions the shoulder could perform. In the middle, there is a steep improvement in function with increasing range. At the right hand of the "S", the curve flattens out so that further improvements in range are not strongly associated with increased function. For the SST the inflection points (thresholds) were 153 degrees for active flexion, 50 degrees of active external rotation, and active internal rotation to L2. Similar thresholds were found for other function-based outcome measures, including the ASES score and the SPADI.
Subjective satisfaction was assessed by asking patients to rate their shoulder as being “worse”, “unchanged”, “better”, or “much better” compared to before surgery. Among shoulders that achieved all ROM thresholds, 93% of patients rated their shoulder as “much better” compared to before surgery.
It is interesting to view these results in the light of data presented in Practical Evaluation and Management of the Shoulder. The authors of that book characterized elevation in terms of the angle of elevation
and the plane of elevation.
Of course the ability to perform functions does not only depend on elevation angle and plane, but also on the rotation of the arm as shown below.
Thresholds For Diminishing Returns In Postoperative Range Of Motion After Total Shoulder Arthroplasty is an important article in that it can help guide motion goals for arthroplasty surgery and postoperative rehabilitation. It suggests that a shoulder that has active elevation to 180, external rotation to 90 and internal rotation to T7 may not be more functional or satisfactory than one has 153 degrees of active flexion, 50 degrees of active external rotation, and active internal rotation to L2.
Comment to shoulderarthritis@uw.edu
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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).
