These authors sought to develop a predictive model for calculating 2-year American Shoulder and Elbow Surgeons (ASES) scores in shoulder arthroplasty patients using a retrospective multicenter study that included 1947 shoulder arthroplasties performed from 2010 to 2015 at 3 high-volume centers.
The variables considered by the authors for inclusion in the model are shown in the table below
The following variables were significantly associated with higher postoperative ASES scores:
higher patient age,
higher preoperative ASES score,
absence of disability,
absence of chronic obstructive pulmonary disease (COPD),
current use of alcohol,
anatomic (rather than reverse total shoulder), and
primary (rather than revision) arthroplasty.
The prediction error was 20.1, the proportion of variance explained was 25.3%, the mean absolute error was 15.9, and the C statistic for the linear regression model was 0.66. After external validation, the mean difference between predicted and actual 2-year ASES scores was 12.7 points, within the accepted minimal clinically important difference after shoulder arthroplasty.
The model was accurate within the minimal clinically important difference in 85% of patients.
Comment: This is an important study in that it reveals that many of the factors commonly thought to be important were NOT necessary for accurately predicting the final ASES score after arthroplasty in the hands of these experienced surgeons:
diagnosis
depression
co-morbidities other than COPD
rotator cuff status
glenoid type (A1, A2, B1, B2, B3, C, D)
preoperative or postoperative glenoid version
preoperative 3D planning
stem type (stemless, short, standard)
glenoid component design
It is of interest that none of the seven important factors identified in this study (listed again below) are modifiable, except for the possibility of using an anatomic rather than a reverse total shoulder when possible:
The following variables were significantly associated with higher postoperative ASES scores:
higher patient age,
higher preoperative ASES score,
absence of disability,
absence of chronic obstructive pulmonary disease (COPD),
current use of alcohol,
anatomic (rather than reverse total shoulder), and
primary (rather than revision) arthroplasty
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