Preoperative factors associated with loss of range of motion after reverse shoulder arthroplasty
These authors point out that reverse shoulder arthroplasty (RTSA) often allows patients to achieve better range of motion (ROM) compared to their preoperative baseline. However, there is a subset of patients who either fail to improve or lose ROM postoperatively. These patients are at increased risk of poor satisfaction and patient reported outcomes (PROMs).
They conducted a retrospective review using the commercial Exactech database of patients undergoing primary RTSA.
123 (7.7%) of the shoulders lost ≥ 10° of forward elevation (FE) (group 1, p1) and 183 (11.4%) lost ≥ 10° of external rotation (ER) (group 2, p2).
Better preoperative abduction, forward elevation, external rotation, and internal rotation were each associated with greater loss of FE and ER postoperatively.
Higher preoperative Simple Shoulder Test (SST) and other scores were also strongly associated with loss of ROM postoperatively.
Other factors associated with a higher risk of losing ROM included a diagnosis of irreparable rotator cuff tear, rotator cuff arthropathy, and inflammatory arthropathy.
On multivariate analysis, higher preoperative forward elevation, internal rotation, and weight remained significant predictors of loss of forward elevation.
Better preoperative forward elevation and external rotation remained as significant predictors of loss of external rotation.
Patients who lost FE or ER were more likely to report lower satisfaction scores than their counterparts who did not lose ROM.
They concluded that surgeons should strongly counsel patients with well-preserved preoperative function on the risk of loss of range of motion.
Comment: It is of note that patients that lost forward elevation had an average preoperative forward elevation of 139 degrees (i.e. did not have pseudoparalysis), in contrast to those who did not lose active elevation (average preoperative elevation of 80 degrees, suggesting pseudo paralysis).
Furthermore, the patients that lost forward elevation had an average preoperative Simple Shoulder Test (SST) of 5 (as opposed to 3 for those that did not loose forward elevation).
It is important to note that an SST of 5 indicates a substantially higher level of preoperative function (or "tipping point") than that for prior studies of the typical functional levels prior to reverse total shoulder as explained in these three posts.
When is the right time to do a shoulder joint replacement?
When should a reverse be done?
Reverse total shoulder: is the tipping point changing.?
Patients with higher levels of preoperative forward elevation may be well served by other approaches (see this link for example).
