Comparative cost-effectiveness analysis of the subacromial spacer for irreparable and massive rotator cuff tears

Abstract

Purpose: There is ongoing debate regarding the optimal surgical treatment of irreparable rotator cuff tears (IRCT). This study aimed to assess within the Italian health care system the cost-effectiveness of subacromial spacer as a treatment modality for patients with IRCT.

Methods: An expected-value decision analysis was created comparing costs and outcomes of patients undergoing arthroscopic subacromial spacer implantation, rotator cuff repair (RCR), total shoulder arthroplasty, and conservative treatment for IRCTs. A broad literature search provided input data to extrapolate and inform treatment success and failure rates, costs, and health utility states for these outcomes. The primary outcome assessed was an incremental cost-effectiveness ratio (ICER) of subacromial spacer implantation versus shoulder arthroplasty, RCR, and conservative treatment.

Results: Subacromial spacer is favorable over both arthroscopic partial repair and shoulder arthroplasty since it costs less than both options and increases effectiveness by 0.06 and 0.10 quality-adjusted life years (QALYs), respectively. While conservative treatment is the least costly management strategy, subacromial spacer results in a gain of 0.05 QALYs for the additional cost of 522 €, resulting in an ICER of 10,440 €/QALY gain, which is below the standard willingness to pay ratio of $50,000 USD. Strategies with an ICER of less than 50,000 USD are considered to be cost-effective.

Conclusions: Based on the available evidence and reasonably conservative assumptions, subacromial spacer is likely to provide a safe, effective, and cost-effective option for patients with massive IRCTs. Furthermore, this cost-effectiveness analysis may ultimately serve as a guide for development of health care system and insurer policy as well as clinical practice.

Keywords: Biodegradable balloon; Cost-effectiveness; Irreparable tears; Rotator cuff tear; Rotator cuff tear treatment modalities; Subacromial spacer.

Fig. 1

Schematic presentation of the InSpace™ system implantation steps: a Step 1: selection of the correct spacer size by measuring the distance from the lateral border of the greater tuberosity to approximately 1–2 cm medial to the glenoid apex, using a surgical probe. The system is available in three optional sizes (small, medium, or large) to accommodate individual patient’s anatomic variations. b Step 2: insertion of the InSpace™ introducer into the subacromial space (the spacer is folded inside). c Step 3: inflation of the balloon-shaped spacer with saline as per spacer size and device’s instruction for use. d Step 4: final position of the sealed spacer in the subacromial space between the humeral head and acromion

Fig. 2

Model structure—treatment alternatives for irreparable rotator cuff tear

Fig. 3

Graph of base case cost-effectiveness analysis. The four competing treatment strategies with model parameters set at the base case scenario (QALYs, quality-adjusted life years)

Fig. 4

Two-way sensitivity analysis plot for utility after successful InSpace™ versus utility after successful rTSA. The colors represent the preferred strategy for the combination of the two parameters based on NMB when a WTP of $50,000 (45,483 €) is used. The InSpace™ strategy is the preferred strategy for most feasible combinations of InSpace™ utility and rTSA utility in a comparison of the three surgical treatments