Variation in the value of total shoulder arthroplasty
Using patient-reported outcomes (2 year ASES scores) integrated with time-driven activity-based costing, these authors explored patient-level variation in the value of anatomic and reverse total shoulder arthroplasty (TSA) and characterized factors that contribute to this variation.
They identified 239 patients undergoing elective primary TSA (anatomic or reverse) by an individual surgeon with minimum 2-year follow-up. They calculated "value" as 2-year postoperative American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores divided by hospitalization time-driven activity-based costs.
After multiplication by a constant, the value of shoulder arthroplasty ranged from 100 to 680.
Factors associated with decreased value were
(1) reverse shoulder arthroplasty (79-point decrease vs. anatomic arthroplasty)),
(2) prior ipsilateral shoulder surgery (38-point decrease),
(3) more self-reported allergies (4-point decrease per 1-unit increase),
(4) diabetes (33-point decrease), and
(5) lower preoperative ASES score (0.7-point increase per 1-unit increase).
Comment: Value is commonly defined as the benefit divided by the cost. It is, therefore, considering the numerator and denominator of this quotient.
The numerator=the benefit
Should the numerator be the final patient reported score or the improvement in the score from preoperative to two years after surgery?
It is likely that a higher preoperative score would be associated with a higher postoperative score (better in => better out), as was found in this study.
Alternatively, if the numerator of the value equation is the improvement in the score, a lower preoperative score is likely to be associated with greater value (worse in => more opportunity for improvement).
The Denominator=the cost
These authors used the time-driven activity-based costing (TDABC) methodology to derive inpatient surgical costs for each patient. In their analysis, procedure type (the more costly reverse vs the less costly anatomic arthroplasty) was the main driver of the variation in value. This is especially relevant now because surgeons are increasingly using reverse total shoulders for indications - such as osteoarthritis with an intact cuff - which are well treated with an anatomic total shoulder.
It is worthy to note that decreased value was associated with
(1) a history of prior ipsilateral nonarthroplasty shoulder surgery. This could be because of a lower 2 year outcome score or possibly because of increased operating room time and supplies necessary for the management of the altered surgical field.
(2) diabetes; the authors suggest that patients with diabetes experience prolonged and more complicated hospitalizations and worse functional outcomes
(3) a greater number of self-reported allergies; the authors suggest that patients with self-reported allergies experience longer hospital stays and severe pain
Finally, it is important to recognize that the full cost of an arthroplasty includes the costs of of preoperative evaluation (imaging, 3D-planning) and postoperative complications and revisions which may occur years after the procedure.
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