Robotic Arm-Assisted Total Hip Arthroplasty Is More Cost-Effective Than Manual Total Hip Arthroplasty

A Markov Model Analysis

David R. Maldonado, MD; Cammille C. Go, BS; Cynthia Kyin, BA; Philip J. Rosinsky, MD; Jacob Shapira, MD; Ajay C. Lall, MD, MS; Benjamin G. Domb, MD

Disclosures

J Am Acad Orthop Surg. 2021;29(4):e168-e177. 

In This Article

Abstract and Introduction

Abstract

Background: Total hip arthroplasty (THA) is the benchmark surgical treatment of advanced and symptomatic hip osteoarthritis. Preliminary evidence suggests that the robotic arm-assisted (RAA) technology yields more accurate and reproducible acetabular cup placement, which may improve survival rate and clinical results, but economic considerations are less well-defined. The purpose of this study was to compare the cost effectiveness of the RAA THA with manual THA (mTHA) modalities, considering direct medical costs and utilities from a payer's perspective.

Methods: A Markov model was constructed to analyze two potential interventions for hip osteoarthritis and degenerative joint disorder: RAA THA and mTHA. Potential outcomes of THA were categorized into the transition states: infection, dislocation, no major complications, or revision. Cumulative costs and utilities were assessed using a cycle length of 1 year over a time horizon of 5 years.

Results: RAA THA cohort was cost effective relative to mTHA cohort for cumulative Medicare and cumulative private payer insurance costs over the 5-year period. RAA THA cost saving had an average differential of $945 for Medicare and $1,810 for private insurance relative to mTHA while generating slightly more utility (0.04 quality-adjusted life year). The preferred treatment was sensitive to the utilities generated by successful RAA THA and mTHA. Microsimulations indicated that RAA THA was cost effective in 99.4% of cases.

Conclusions: In the Medicare and private payer scenarios, RAA THA is more cost effective than conventional mTHA when considering direct medical costs from a payer's perspective.

Level of Evidence: Economic Level III. Computer simulation model (Markov model)

Introduction

Osteoarthritis (OA), one of the most common forms of joint disease, is a major cause of hip pain and functional disability. Resulting pain and stiffness can decrease the quality of life and impair patient ability to perform activities of daily living. As the 11th highest contributor to global disability, the incidence of hip OA worldwide is 0.85%, affecting 10% of men and 18% of women aged older than 60 years.[1] This incidence is only expected to increase, in part because of an aging society.[2] Furthermore, the costs associated with OA can be considerable, with total annual direct costs for patients with OA were estimated to be over two times higher than similar patients without the condition.[3,4] The annual average direct cost—hospitalization, emergency department visits, physician visits, outpatient visits, medications, and others—has been estimated to vary from $1,442 to $21,335 in the United States, placing a strain on the limited health care resources available.[5] Substantial indirect costs—absenteeism, presenteeism, disability, and worker's compensation, which range from an average of $238 to $29,935—serve to further increase the economic burden of OA.[5]

Total hip arthroplasty (THA) is considered the treatment of choice for end-stage OA, resulting in favorable functional outcomes and substantially increased quality of life.[6,7] In most cases, patients can expect their hip arthroplasty to last at least 25 years.[8] Owing to the increasing incidence of OA, the demand for primary THA has been projected to likewise increase by severalfold by 2030.[9] Furthermore, dislocation after primary THA continues to be a prevalent and costly complication that diminishes the cost effectiveness of an otherwise very successful surgical procedure. The average hospital costs of one or more closed reductions and the subsequent revisions represented 148% of the hospital cost of an uncomplicated primary total hip arthroplasty.[10] Placing the acetabular implant in a target zone may not eliminate the risk of dislocation, but it could possibly minimize this risk, as such, meticulous attention to component position is key.[11]

Robotic arm-assisted (RAA) THA offers several advantages over conventional or manual THA (mTHA). RAA THA surgery allows the surgeon to translate preoperative planning to intraoperative execution with surgical accuracy and precision.[12,13] The ability to execute a precise preoperative plan during surgery through RAA THA may benefit less experienced surgeons.[14] RAA THA has also been reported to have markedly higher accuracy when positioning implants in THA,[13,15–17] which is key for long-term implant survivorship. Illgen et al,[17] reported 0% dislocation rate after primary RAA THA at the 2-year follow-up in a cohort of 100 consecutives patients. Given that the costs associated with THA can be substantial, there exists a need for an economic evaluation to determine the relative merits of new technology in THA surgery.

The purpose of this study was to compare the cost effectiveness of the RAA THA with mTHA modalities, considering direct medical costs and utilities from a payer's perspective. Our primary hypothesis was that RAA THA would be cost effective for payers over medium-term follow-up. This analysis strictly considers direct medical costs and utilities to the payer as a consequence of surgical treatment choice to inform payers about viability of the relative THA modalities.

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