Cost Analysis and Reimbursement of Weightbearing Computed Tomography

Abstract

Background:

Weightbearing computed tomography (WBCT) is becoming a valuable tool in the evaluation of foot and ankle pathology. Currently, cost analyses of WBCT scanners in private practice are lacking in the literature. This study evaluated the costs of acquisition, utilization, and reimbursements for a WBCT at a tertiary referral center, information of particular interest to practices considering obtaining such equipment.

Methods:

All WBCT scans performed at a tertiary referral center over the 55-month period (August 2016 to February 2021) were retrospectively evaluated. Patient demographics, pathology location, etiology, subspecialty of the ordering provider, and whether the study was unilateral or bilateral were collected. Reimbursement was calculated based on payor source as a percentage of Medicare reimbursement for lower extremity CT. The number of total scans performed per month was evaluated to determine revenue generated per month.

Results:

Over the study period, 1903 scans were performed. An average of 34.6 scans were performed each month. Forty-one providers ordered WBCT scans over the study period. Foot and ankle fellowship-trained orthopaedic surgeons ordered 75.5% of all scans. The most common location of pathology was the ankle, and the most common etiology was trauma. The device was cost neutral at 44.2 months, assuming reimbursement for each study was commensurate with Medicare rates. The device became cost neutral at approximately 29.9 months when calculating reimbursement according to mixed-payor source.

Conclusion:

As WBCT scan becomes more widely used for evaluation of foot and ankle pathology, practices may be interested in understanding the financial implications of such an investment. To the authors’ knowledge, this study is the only cost-effectiveness analysis of WBCT based in the United States. We found that in a large, multispecialty orthopaedic group, WBCT can be a financially viable asset and a valuable diagnostic tool for a variety of pathologies.

Level of Evidence:

Level III, diagnostic.

Introduction

Weightbearing CT (WBCT) is a technology that has shown utility in the evaluation and treatment of foot and ankle pathologies. Initially used commercially in maxillofacial imaging in the 1990s, cone-beam imaging involves a conical X-ray beam and a flat image intensifier that rotates around an anatomic region of interest. Algorithms are used to translate data into 3-dimensional (3D) models from which reconstructions of orthogonal planes can be made. The data collected from a cone beam CT scanner can also be used to create traditional radiographic projections without having to take multiple images. Recent studies have demonstrated that WBCT can provide more accurate information on the 3D relationships of osseous structures of the foot and ankle than radiographs or conventional CT scans and require less time for image aquisition. ²¹ WBCT also exposes patients to significantly lower doses of radiation than conventional CT scans, although estimates of true radiation exposure vary.^4,15,20 The smaller footprint of WBCT and decreased need for shielding make it a convenient technology to incorporate into in-office radiology departments. As WBCT becomes more widely used in orthopaedic practice, understanding the costs related to its acquisition and reimbursements will be of increasing interest.

To the authors’ knowledge, no cost analyses of WBCT in the United States have been reported in the literature. The primary purpose of this study was to evaluate the cost of utilization of a WBCT in a tertiary referral, physician-owned practice. Secondarily, the utilization of WBCT based on orthopaedic subspecialty, location, and etiology of pathology was investigated.

Materials and Methods

After obtaining institutional review board approval, all WBCT scans performed from the time of initial acquisition of the device on August 16, 2016, through February 19, 2021, were retrospectively analyzed. Age, patient gender, pathology location and etiology, unilateral vs bilateral imaging, subspecialty of the ordering provider, and payor source were collected. The location of the primary pathology was categorized into ankle (tibiotalar joint), hindfoot (transverse tarsal joint to subtalar joint), midfoot (tarsometatarsal to transverse tarsal joint), and forefoot (distal to tarsometatarsal joints). The pathology was further categorized as trauma, developmental, degenerative (including Charcot), tumor, fusion/healing, ulcer, or hardware evaluation. Sprains and stress fractures were categorized under trauma for evaluation purposes. If multiple sites of significant pathology were noted, both locations and pathologies were counted. The payor source was categorized as private insurance, self-pay, worker’s compensation insurance, Medicare, or Medicaid. Costs associated with device acquisition and maintenance were obtained from a pro forma analysis performed prior to purchase. The device used in this practice was a PedCat WBCT scanner, with a cost of $179000 including in the extended warranty, which cost $30000.

Results

This study included 1704 unique patients. Fifty-four percent (920 patients) were female, and 46% (784 patients) were male. Ages ranged from 6 to 92 years (average age 44 years), with 206 patients being under the age 18 years. The average number of scans performed per patient was 1.12 (range of 1-5). During the 55-month collection period, 1903 WBCTs were performed, of which 101 were bilateral studies. An average of 34.6 scans were performed each month (range 18-50 scans). Forty-one providers from 9 subspecialties used the device. Five foot and ankle fellowship-trained surgeons ordered 1438 studies over the collection period, yielding an average of 26.6 scans per month. Other specialties that significantly used the device were physical medicine and rehabilitation/physiatry (126 studies) and pediatric orthopaedics (86 studies). The provider who ordered each study would follow the patient unless they had pathology that necessitated evaluation by a fellowship-trained foot and ankle surgeon. A breakdown of WBCT ordered by specialty can be seen in Figure 1. Physician assistants (PAs) were not broken down by subspecialty for the purposes of this study.

Figure 1.

Utilization of weightbearing CT scanner by provider specialty. Foot and ankle–trained providers used the device most commonly, followed by nonoperative sports, physical medicine and rehabilitation/physiatry (PM&R), and pediatric orthopaedic surgery.

When WBCT use was evaluated based on location of pathology, 8.5% (152/1898) was for forefoot pathology, 25.7% (488/1898) for midfoot pathology, 27.6 (525/1898) for hindfoot pathology, and 38.1 (723/1898) for ankle pathology. The most common disease processes evaluated by WBCT in this cohort were trauma (54%, 981/1816), degenerative diseases (30%, 546/1816), fusion/healing assessment (10%, 179/1816), congenital/developmental anomalies (4%, 67/1816). Tumors, hardware evaluation, arthroplasty evaluation, and ulcers accounted for <1% each. (11/1816, 9/1816, 9/1816, and 14/1816, respectively).

The procurement cost was $179000 for the device, $30000 for the extended warranty, and $995 for 1-time licensing fees, giving a total of $209995. Staffing costs were negligible as the device is run by already employed radiology technicians during normal business hours; thus, there is minimal to no additional cost in salary or employee hours. The daily number of scans is low; thus, we surmise that most groups with in-house radiology would be able to use this technology without having to increase staffing.

To allow for ease of analysis and applicability of information across orthopaedic practices, Medicare reimbursement of $163.50 for Current Procedural Terminology (CPT) code 73700, Diagnostic Radiology (Diagnostic Imaging) Procedures of the Lower Extremities, was used as a baseline for compensation. Private insurance, workers’ compensation insurance, and self-pay reimbursements were estimated to be 180% of Medicare, yielding $294.30 in reimbursement per scan. Medicaid was calculated to be 61% of Medicare reimbursement, resulting in $99.74 per scan. These values were calculated after a review of the literature comparing reimbursement of Medicare vs private insurance and Medicare vs Medicaid for in-hospital and out-of-hospital services.^1,14 These values do have heterogeneity based on geographic area and a health system’s negotiated prices with insurance providers; however, the authors thought that these multipliers were conservative enough to be widely applicable.^1,14 Each CPT code was billed for the global fee; a contracted fee consisting of 16% of the global fee was then paid to the radiology group interpreting the images. Thus, the technical component of a CT scan performed on a Medicare-insured patient would net $137.34, a privately insured, workers’ compensation, or self-pay patient would net $247.2, and a Medicaid insured patient would net $83.79.

Regarding payor source, 61% (1101/1802) of patients were privately insured, 19% (340/1802) were Medicare insured, 15% (262/1802) were Medicaid insured, and 5% (95/1902) were under worker’s compensation (Figure 2). Based on an average number of 34.6 scans per month, the WBCT scan generated $4751.96 in gross revenue, assuming Medicare-only reimbursement rates for all scans, and $7014.08 per month gross revenue based on mixed-payor source reimbursement specific to the authors’ institution. Based on these amounts, it would take 44.2 months to pay off the device at Medicare reimbursement rates and 29.9 months to pay off the device on mixed-payor reimbursements. It should be noted that this time frame will vary significantly based on each institution’s payor mix distribution and the total number of scans ordered.

Figure 2.

Payor source. The majority of patients in our study were privately insured (1101/2802), followed by Medicare (340/1802), Medicaid (262/1802), worker’s compensation (95/1802), and self-pay (4/1802).

To earn back the total cost of the device, 1529.0 scans would have to be performed at Medicare-only reimbursement rates, and 1035.9 scans would have to be performed at mixed-payor rates. For the purposes of this study, we amortized the initial and ongoing costs over a 60-month period and found that 25.48 scans were needed per month to break even, assuming all-Medicare reimbursement or 17.26 scans using our institution’s payor mix. If the repayment were amortized over a 120-month period, 12.74 scans per month for all Medicare reimbursement and 8.63 scans for mixed payors would be required for the device to become cost neutral. Assuming an average life span of 10 years for the machine, that leaves a profit of $360240.68 to $631694.29. These figures disregard some benefits and potential cost savings, including the ability to more accurately template and plan for procedures, decreased time to accurate diagnosis, and personnel savings associated with reduction in time required to obtain imaging compared with standard foot and ankle radiographs.^2,3 This calculation may also underestimate the increased costs associated with operating the machine over years 6 to 10. The device at this institution has been in use for 7 years without significant issue.

Discussion

To the authors’ knowledge, no studies exist evaluating the cost effectiveness of WBCT in a US-based orthopaedic practice. Several studies based on a large patient cohort in Europe have been published; however, these results have limited applicability in the United States because of the significant differences in reimbursements and health care expenditures between the European Union (EU) and US health care systems. Richter et al^{2,17 -19} demonstrated that WBCT decreased the time to image acquisition by 12 minutes per patient, decreased average radiation exposure, and increased income from 19 to 58 euros per patient. The increased income per patient in these studies was primarily the result of decreased staffing costs for image acquisition as only 15.1% of their cohort was not insured by a single payor system and generated income directly from the imaging services. WBCT was also used as the primary imaging modality at this institution during the study period, leading to comparatively high volumes of WBCT’s being performed. The authors believe that WBCT is a useful adjunct to plain radiographs of the foot and ankle, but it has not become the primary imaging modality at this institution.

Limitations of this study include a lack of a standard protocol for imaging of foot and ankle injuries in our group. Additionally, our study primarily serves as a case example of one institution’s experience with WBCT from primarily a reimbursement perspective. Differences in personnel cost were not evaluated. Many factors vary across the country and individual institutions that should be considered, including number of providers in the area or group that would contribute to the number of scans per month, payor mix, and insurance contracts for reimbursements, to name a few. This study was performed at a tertiary referral center with 5 foot and ankle–trained surgeons; smaller practices may have issues using the technology enough for it to be financially viable. To allow for wide applicability across practice settings, the multiplier for the reimbursement paid by private insurance in comparison to Medicare was set at 180% for this study. A review of the literature showed that this value ranges from 161% to 358%, so this value may vary widely based on contract negotiations between practices and insurers; however, we thought that 180% would provide a broadly applicable and appropriately conservative estimate.^1,14 When evaluating the financial viability of using a similar device, readers would be encouraged to base it on the regional or group-specific reimbursement rates.

Future areas of study include further evaluation of cost efficacy, more accurate assessment of reimbursement for non-Medicare carriers, evaluation of costs associated with operating the device. Evaluating the effect of WBCT on length of patient encounters and time between imaging being ordered and the study being performed, as well as, patient perception of WBCT vs traditional imaging modalities could be future areas of study. Comparison of the number of CT’s ordered prior to implementation of WBCT in this center vs after would be another area of interest. WBCT has shown to be a cost-effective tool for the evaluation of lower extremities at this institution. The technology has benefits over traditional helical CT scans in evaluating the foot and ankle under physiologic loads, the primary benefit, however, likely stems from the convenience of having this technology available in office for use instead of traditional CT for nonweightbearing studies. The lower radiation dose and ease of image acquisition may lead to more studies being performed; however, the literature has yet to bear out whether this leads to more accurate diagnosis. This modality has not replaced standard radiographs but has proven to be a valuable addition to diagnostic imaging at this tertiary referral center.

Conclusion

Based on the authors’ experience, WBCT appears to be a potentially financially profitable technology for evaluating a variety of foot and ankle pathologies in a private orthopaedic practice. Some authors have transitioned to using WBCT as the primary modality for foot and ankle imaging, stating a savings in image acquisition time compared to traditional imaging modalities, with an acceptable radiation dose.^4,20 WBCT was used in this practice for a variety of pathologies but was most used for evaluating traumatic injuries and degenerative processes about the foot and ankle. WBCT has not replaced traditional radiographs in this practice for initial imaging of lower extremity complaints. Because of this, we do not believe that there is any revenue lost on plain radiographs by using this technology in appropriately indicated patients. The most evaluated location in our cohort was the ankle, which differs from the experience of some other authors.^5,6,9 WBCT has been demonstrated to be a useful modality for assessing the complex 3-dimensional relationships of the osseous anatomy of the foot and ankle under physiologic load.^2,11,12 This is partly due to the lack of rotational and projection bias. ¹ Recent studies have investigated acquired flatfoot deformity, hallux valgus, syndesmotic injury, sesamoid position, lateral ankle instability, and first metatarsal position^7,8,10; however, there is still debate on the most accurate method of deformity measurement and what constitutes a clinically significant abnormality or a subclinical deformity.^13,22 The effect of weightbearing on specific radiographic measurements also remains a topic of study because some measurements demonstrate statistically significant differences between weightbearing and nonweightbearing imaging modalities.^3,16,22