Is blockchain ready for orthopaedics? A systematic review

Abstract

Introduction

The unique attributes of distributed ledger blockchain systems including robust security, immutability, transparency, and decentralisation, make them highly suitable solutions for many healthcare-related problems. This review examines the potential applications for blockchain technology in the field of orthopaedics, by taking a systematic approach to the evolving blockchain literature and mapping potential use cases against the current needs of orthopaedic practice.

Method

A literature search was performed using Pubmed, EMBASE, OVID and the Cochrane library with the primary aim of identifying detailed accounts of blockchain solutions and use cases in healthcare. These articles were then reviewed and mapped against current orthopaedic practice to illustrate applications specific to that specialty.

Results

One hundred and forty-one papers were identified which described case studies, simulations, or detailed proposals of blockchain solutions in healthcare. Most studies described blockchain solutions at the simulated or prototype testing phase, with only 10 case studies describing blockchains in “real-world” use. The most frequently cited use cases for blockchain technology involved the storage, security and sharing of electronic medical records. Other blockchain solutions focused on the “Internet of Things”, research, COVID 19, supply chains and radiology. There were no solutions focusing specifically on orthopaedics. Many of the described blockchain solutions had considerable scope for application in orthopaedic practice however, providing the potential for greater inter-institutional collaboration, cross border data exchange, enhanced patient participation, and more robust and transparent research practices.

Conclusion

Blockchain solutions for healthcare are increasing in number and scope and have multiple applications relevant to orthopaedic practice. The orthopaedic community needs to be aware of this innovative and growing field of computer science so that surgeons can leverage the power of blockchain safely for the future of orthopaedics.

1. Introduction

A quiet revolution is currently taking place which is set to transform the practice of orthopaedics. That revolution is being driven by blockchain technology, which underpins cryptocurrencies such as Bitcoin,¹ but which is also highly applicable to the world of medicine. In essence, blockchain provides a framework for building decentralised networks for communicating value, trust and confidence; three of the cornerstones of modern orthopaedic care. These networks have the potential to radically alter the relationship between surgeon and patient, researcher and subject, the government, healthcare institutions and their employees. To make the most of this new and rapidly evolving landscape, orthopaedic surgeons will need to develop an understanding of the technology and its future applications (see Fig. 1).²

Fig. 1.

A schematic representation of the blockchain paradigm.

2. Blockchain: A technology summary

Although blockchain is in some ways a complex technology, it relies on a basic set of principles which are easy to understand and apply. Fundamentally, it is a shared database that records data and transactions between parties in an immutable ledger. In its most elemental form, a blockchain consists of connected blocks of computerised data each with a unique digital signature or “hash” which is altered if the contents of the block are altered. Each block also contains a copy of the hash of the preceding block in the chain, which therefore identifies the position of the block and connects the blocks together. As the chain of blocks is built, the whole sequence is recorded on an online ledger, which can be accessed by those individuals with permission to join the network. (In the example of Bitcoin, the ledger is distributed and entirely public).

Each blockchain has a protocol or “consensus mechanism” for validating the blocks as they are added to the chain. The blockchain is accessible to and managed by multiple participants or “nodes” who must reach a consensus on the validity of each new block before it is added to the chain. If the data in any of the blocks is tampered with, the hash of that block and all other downstream blocks is automatically altered. This discrepancy is visible to all the other nodes in the network and will not receive consensus approval. The use of secure cryptography, the consensus mechanism, and the distributed structure of the ledger means that it is extremely difficult for individual actors to modify the blockchain illegitimately, making blockchain protected data highly secure and tamper resistant.

3. Blockchain in healthcare and orthopaedics: A systematic literature review

3.1. Method

To identify viable applications for blockchain in orthopaedics, a systematic review was performed. The Pubmed, EMBASE, OVID and Cochrane library databases were searched using the search string “blockchain” AND (“health” OR “healthcare” OR “orthopaedic”). To ensure the literature was up to date in this rapidly evolving field, the search was limited to the period January 1, 2017 to July 1, 2021. All peer reviewed articles were included in the subsequent review stage, whilst letters, editorials, conference abstracts, proposed study protocols and policy documents were excluded. The remaining abstracts were reviewed, and papers were categorised by format, and blockchain subtopic. All abstracts describing case studies, simulations or detailed descriptions of proposed applications were then reviewed in full, with the aim of mapping their applicability to the current orthopaedic healthcare environment. Described blockchain systems were categorised based on the extent to which they were “service ready” for real world use. The extracted data were synthesised and presented narratively, with several case studies used to introduce additional blockchain concepts and features throughout the piece. In order to focus the review, the top three subtopics were selected for in depth discussion.

3.2. Results

The electronic database searches yielded 306 unique abstracts from peer reviewed articles. There were 141 articles reporting real world blockchain case studies, simulations or detailed descriptions of proposed applications. The remainder of the articles included 132 narrative reviews, 24 systematic reviews, 8 surveys of professionals or patients, and 1 qualitative study. Table 1 records the relationship between case studies/proposed applications and blockchain related subtopics, demonstrating the current focus towards blockchain solutions for electronic medical record (EMR) management, “Internet of Things” (IoT) data management, and research. Table 2 charts the rapid growth in published articles in this field since January 2017. Table 3 illustrates that the majority of described blockchain solutions were at the simulation/prototype testing phase, with only 10 case studies describing solutions operating in a “real world” context. Table 4 provides a summary of the essential characteristics of these 10 articles.

Table 1.

Bar chart indicating the number of peer reviewed articles providing detailed descriptions of use cases in particular areas of healthcare and health related technology. (EMR = electronic medical records, COVID= COVID-19 Pandemic, IoT = Internet of Things, AI = Artificial intelligence).

Table 2.

Bar chart indicating the number of peer reviewed articles involving detailed case studies, simulations or proposals published per month since January 2017.

Table 3.

Bar chart indicating the number of peer reviewed articles versus the service readiness of the blockchain solution described in each article. Case studies include those solutions tested in real world situations, typically with genuine patients. Simulation/Prototype testing refers to solutions which have undergone testing in a virtual environment only. “Proposals/Theoretical framework” refers to solutions which constitute proposals or ideas which have not been sufficiently engineered to allow virtual testing.

Table 4.

Summarising the key characteristics of the 10 articles reporting blockchain solutions operating in a live or “real world” context.9, 10, 11, 12, 19, 21, 23, 25, 32, 50

4. The application of blockchain technology in orthopaedics

4.1. Electronic medical records and imaging

The systematic review identified the storage, protection and sharing of electronic medical records (EMR) as a clear focus of current blockchain research in healthcare. Sixty-five articles described blockchain solutions specific to this area, which is also of critical importance to the orthopaedic community, who rely increasingly on the safe and efficient transmission of diagnostic data, imaging, and operative records in everyday practice.

Currently EMRs are often stored by multiple institutions on poorly integrated systems. Delays in data sharing frequently lead to the duplication of diagnostic imaging in particular,³ and valuable clinical information about previous implant and operative history is often unavailable. Obtaining EMR information can be particularly difficult for patients who have received their initial care outside a state, national or supranational regulatory boundary over which it can be especially hard to transmit pertinent clinical data (for instance the EU GDPR⁴). Although the online “cloud” storage of health records has made data sharing easier, these innovations often come at the expense of patient privacy, with high profile online security breaches now a feature of healthcare practice in many jurisdictions.^5,6

The secure, immutable, and distributed characteristics of blockchain technology make it a promising innovation for addressing the dynamics of these data storage and sharing problems.⁷ Blockchains are difficult to access without permission, and the information stored on them is hard to modify or corrupt. Blockchains in healthcare applications are generally “permissioned”, with access rights reserved only for the relevant stakeholders, in contrast to the “public permissionless” blockchains such as the Bitcoin ledger. Data access management requests using blockchain are typically carried out using a combination of public and private “keys”,⁸ which are used in combination to encrypt/send and decrypt/receive data (see Fig. 2).

Fig. 2.

An example of a cryptographic transaction, involving an image request and approval, using a pair of public and private keys.

In a typical system, for example the medical image sharing network described by Patel,⁹ the patient and hospital are provided with key pairs which allow participants to make transactions on the blockchain, receiving and approving access requests to medical imaging which is stored “off chain” at the originating hospital. Through blockchain transactions, patients can give permission for individual clinicians to access the imaging, or for transfer of the image from one institution to another. The blockchain records and audits access to the imaging record, and the patient remains in control of the entire process.

To ensure that the system is user friendly, a mobile phone interface is often included in the described designs.¹⁰ Some of these apps have also been extended to allow patient-initiated upload of medical data to the EMR. For example, in several validated blockchain based solutions, patients were able to use a mobile app to upload sleep patterns when undergoing treatment for insomnia,¹¹ or to record blood glucose levels,¹² a process which could also be deployed in the orthopaedic setting to collect post-operative pain scores, patient related outcome measures and step counter information for example.

Prototype testing of an international blockchain based EMR exchange platform has also been undertaken,¹³ which directly addresses the problems created by cross-border exchange of sensitive medical data. This platform, which incorporates the Fast Healthcare Interoperability Resource (FHIR)¹⁴ global industry standard for medical data exchange, was able to rapidly and securely transmit EMR data between several southeast Asian countries within the Asia eHealth Information Network, where a simulated patient required access to emergency medical services whilst abroad. Another FHIR-compatible blockchain solution, the “FHIRChain”,¹⁵ demonstrates how the enhanced security and efficiency of data sharing can support remote multi-disciplinary team (MDT) work. This case study described a remotely convened oncology MDT service, which is a highly compatible model for orthopaedic MDT working, making national and international orthopaedic MDT groups viable, for example in the treatment of rare musculoskeletal conditions.

“Smart contracts”¹⁶ constitute an additional feature of some blockchains which can be utilised to automate some EMR data access requests. Smart contracts are programs stored on the blockchain that are run when preconditions are met, without the need for further intervention on the part of the user or any intermediaries. Examples of blockchain platforms capable of running smart contract programs include Ethereum¹⁷ (primarily a public blockchain, which can be configured into a permissioned blockchain), Hyperledger Fabric¹⁸ (a permissioned blockchain), and Multichain¹⁹ (a private blockchain).

In relation to EMR access management, smart contract programs can be set to execute data processing requests based on a pre-configured protocol, and can interact with one another,²⁰ greatly simplifying the number of digital transactions that the patient has to oversee. Zhaung et al.²¹ describe an example of smart contract automation for data access requests in a typical secondary care setting using the Ethereum blockchain platform. When a patient provides consent for institutional access to their EMR, the smart contract runs automatically, vetting individual clinicians from the institution, distributing only selected records appropriate to the requester, and initiating verified access requests to other hospitals to retrieve relevant patient specific data (see Fig. 3).

Fig. 3.

A schematic representation of the flow of information through a healthcare orientated blockchain.

The case studies described demonstrate efficient and secure systems of data management. Because these systems are shared and managed by multiple nodes, a highly decentralised data infrastructure is created which does not rely heavily on any single piece of hard or software infrastructure. This means that blockchain networks are typically more resistant to catastrophic failure, (both malicious and accidental) and less exposed to individual institutional and bureaucratic failures than conventional infrastructure. The resilience of these systems is neatly demonstrated by one Japanese clinical trial team whose blockchain platform continued without disruption despite a major cloud server shut down in Tokyo during the study period.²² Despite these advantages, several security threats still pose a risk in blockchain supported systems. Mobile phone devices in particular are vulnerable to root exploit malware which can fundamentally undermine the security of a connected blockchain platform.²³ In addition, blockchain solutions are unable to protect patients’ data against inappropriate secondary data access facilitated by professionals and institutions (i.e. authorized access but subsequent unauthorised data sharing), for which separate security arrangements need to be considered.

4.2. Global big data orthopaedic research

By facilitating efficient and secure data sharing, in an immutable, time-stamped, and distributed format, blockchain also has the potential to facilitate a new era of inter-institutional and cross-border collaboration in orthopaedic research.

Fourteen papers described detailed research-specific blockchain solutions, although none were specific to orthopaedic care. Six of these studies used smart contract technology as a central aspect of the data management process. In a typical example, Omar et al.²⁴ utilise smart contracts, to develop a system in which decisions about data handling are removed from the conventional centralised institutional model and distributed between multiple different institutions, each with guaranteed access rights. This prevents data hoarding, promotes transparency, and allows each institution to monitor the data usage of other collaborators.

This shared model safeguards data integrity. For example, by processing raw data from a real clinical drug trial in a blockchain-protected system, Wong et al.²⁵ show how simulated attempts to conceal adverse clinical events at one study centre generates an instantly visible notification, recording the time and nature of the attack, and transmitting the identity of the responsible party to the other participating institutions.

With a multi-institutional model of research data ownership, otherwise unconnected research teams can carry out statistical cross-checking of data, provide alternative and competing data interpretation, and distribute the same results with a variety of novel conclusions, ensuring the most effective use of the collected data, and promoting a more rigorous, and more vibrant research data economy. Blockchain smart contracts also support other complex data usage models. For example, they can ensure where appropriate that grant holders retain exclusive access to detailed results whilst sharing a subset more publicly for an extended period and could also be utilised to address data legacy issues, by automatically destroying data after (or protecting it for) a pre-determined post study period.

By facilitating a scalable, trusted data sharing framework for collaborators,^26,27 particularly on the international stage, blockchain provides new opportunities for the orthopaedic research community to aggregate data, particularly where study populations are small, for instance in the study of rare congenital and genetic musculoskeletal diseases. Collaborative blockchain solutions may also facilitate a more networked global arthroplasty registry system. Previous projects which amalgamated international registry data have produced enhanced clinical insights,^28,29 but data capture and project longevity presented considerable obstacles. For example, using conventional methods, the international GLORY project, which ran between 2005 and 2014 could only achieve a 70% follow up rate at 3–12 months.²³ The robust, scalable blockchain paradigm offers a more seamless and more robust approach to sharing international implant performance data between individuals and institutions.³⁰ Where cross border data risks are a particular concern, patient identifiable data can be shed from the system prior to data exchange.³¹

Blockchain technology may also be able to promote transparent research processes. For example, Omar et al.³² show how an Ethereum-based research platform can be used to upload and time-stamp a number of prospectively described research conditions onto a blockchain using the Interplanetary File System (IPFS). Study aims, inclusion criteria, and proposed statistical methods are effectively “locked in” prior to the commencement of the study. Smart contracts written onto the blockchain facilitated automatic transfer of patient monitoring data from a simulated clinical drug trial to the Food and Drug Administration (FDA) at set data breakpoints in order to fulfil safety monitoring requirements.

This workflow could be adapted readily to the orthopaedic research arena where good research practices also depend on faithful adherence to a prospectively designed study protocol. This eliminates, amongst other things, the practice of retrospective statistical “data dredging”, and other post hoc modifications designed to mask unfavourable results, preventing the intrusion of researcher biases at each stage of the research process.³³

Literature review practices may also benefit from the advantages of blockchain. Bansal et al.³⁴ propose a blockchain platform designed to record publicly the papers reviewed during a systematic review process, the decisions made about eligibility, and a method by which the review can be updated as new material becomes available, making the process both reproducible, and updatable.

From the point of view of study participants, blockchain technology also offers a flexible means by which patients can opt in and out of research. Patients have been shown to respond favourably to these blockchain based digital consent processes³⁵ and this may in turn promote greater public participation.

Zhaung et al.,³⁶ describe a generalizable healthcare-specific blockchain system, in which interested members of the public interact with a list of studies on a user-friendly app, identifying themselves for studies based on published inclusion criteria. After provisional enrolment, participants set permissions for access to their records using a smart contract, researchers cross check participant suitability and can then formally enrol patients. In this simulated model, sponsors successfully received access permission in 3.07 s.

By setting up this kind of data access protocol and allowing it to be managed with a high degree of automation, patients can make a prospective decision³⁷ to participate in multiple research studies without providing individual consents, or dealing directly with study teams, whilst knowing that their sensitive data is reliably protected. An immutable audit trail of the consent process can also be generated.³⁸

4.3. The Internet of Things; connecting blockchain to implants and people

Twenty-five prototype studies or detailed proposals involving IoT and blockchain were identified during the systematic review, representing the second largest group of articles. The “internet of things”³⁹ (IoT) is an emerging technology which compliments the blockchain landscape, and which has important applications in healthcare settings and potentially also in orthopaedic practice. IoT devices are typically small, everyday items which can communicate wirelessly with each other over the internet (for example, new “smart home” heating and lighting technology). They are typically cheap, have limited functionality and are appropriate for mass production.

In healthcare settings, wearable or implantable IoT devices have been utilised to record and wirelessly transmit real time patient data to clinicians and researchers. To secure that data, IoT devices are often integrated with blockchains in order to protect and manage the uploaded data, which gives the patient confidence in the system to which they are connected.

A detailed account of an IoT integrated blockchain system⁴⁰ describes an IoT wearable device, which records basic patient data such as temperature and heart rate and transmits this to a blockchain protected database with smart contract access control. Authorized physicians can access the data remotely and adjust medications and treatment plans based on the observations. In orthopaedic practice this system could also be utilised, providing a means of careful patient monitoring post discharge, for example screening for signs of post-operative infection, and providing real time rehabilitation intelligence with the use of step counters.

Blockchain-connected IoT devices are also increasingly being deployed in medical supply chains (when placed within packaging) to provide evidence of an unbroken period of refrigeration during transit⁴¹ which is a key requirement when distributing orthopaedic products such as bone and nerve allograft. Devices of this nature record environmental temperatures continuously, and upload that data to a time stamped, immutable blockchain platform. This provides assurance to the surgeon and patient that the product remains suitable for use after transit.

In fact, blockchains can also be deployed to guarantee other important aspects of the orthopaedic supply chain, including the provenance of medical products such as antibiotics^42,43 and implants,⁴⁴ protecting the market and patients from counterfeit medical supplies.⁴⁵ In a typical blockchain supported supply chain (illustrated in Fig. 4), orthopaedic implants enter the supply chain via the manufacturer, who also enters a unique identifier for the product onto the blockchain. A clone-proof QR code, attached to the product, can then be cross-checked against the blockchain record at each stage of transit, which records and timestamps the transfer of the package each time it changes hands from manufacturer to distributor, and finally to the customer who then uses the QR code on the packaging to obtain details about its origins and journey, including the conditions during transport if IoT sensor devices are also integrated into the system.

Fig. 4.

A schematic representation of a blockchain-supported supply chain for orthopaedic implants.

These new processes minimise the need for intermediary regulatory oversight, cutting costs and thereby potentially increasing the availability of these materials to orthopaedic patients globally. Despite these possibilities, blockchain/IoT supply chains also have significant limitations which should be borne in mind. In particular, many current blockchains struggle with the volume of data generated both by large numbers of IoT devices and by the number of transactions in a complex global supply chain.⁴¹

The fundamental security of IoT devices in themselves also constitutes another significant challenge. This is because the low cost and technological simplicity of such devices makes them easy to modify, counterfeit, or corrupt.⁴⁶ In such situations, the validity of the blockchain ledger tracking the devices is undermined and becomes redundant. Providing more secure IoT protocols is an economic rather than a technical issue however, and there are many cases, such as the supply of orthopaedic implants, in which the integrity of the supply chain might have sufficient value to make it economically justifiable.

5. Obstacles in the way of a blockchain revolution in orthopaedics

This review has identified a growing number of use cases for blockchain technology which are applicable to orthopaedics. Much of the described software solutions are open source and readily available. In addition, several commercial solutions are available which are not reported in peer-reviewed academic articles. It is clear however, that many described solutions are at an early stage of development, and do not report the results of real-world testing, with only a few systems in mainstream use. These platforms require further development, and the engagement of surgeons and institutions will be crucial in the transition of this novel and complex technology to real-world use.

To accommodate new blockchain platforms, there will need to be considerable capital investment in new infrastructure. A blockchain based global arthroplasty registry for example, would require geographically distinct healthcare systems to develop interoperable data platforms. The protocol governing a global blockchain platform would also need to undergo a process of negotiated constitutional development involving all the relevant stakeholders, to address access and administrator rights and other data governance issues.⁴⁷ These blockchains will ideally avoid the high energy costs of some current blockchains,⁴⁸ which present significant economic and ecological problems.

Whilst blockchain solutions are highly secure in the current cybersecurity landscape, the web security industry is constantly in flux, and new risks continue to emerge. Computers are becoming exponentially smarter, and a new generation of quantum computers,⁴⁹ not yet outside the laboratory, may develop the capability to crack the cryptographic controls underlying blockchain, and this would be highly disruptive, if not terminal, to the blockchain ecosystem. In fact, such a situation would cause a fundamental crisis in the security of the internet as a whole. Such a capability is currently theoretical but will require careful monitoring.

6. Implications and limitations of this review

This review is the first of its kind to explore the readiness and suitability of blockchain technology specifically for orthopaedic practice. In doing so, it aims to bridge the knowledge gap between a complex and evolving area of computer science and a diverse lay community of orthopaedic surgeons. Broad search terms were employed for the review process in order to encompass the true spread of the available literature. By utilising this broad approach, the review was able to identify a large number of individual use cases, and was able to illustrate the rapid temporal evolution of this technology in the wider healthcare industry.

The approach employed by this review limits its scope in several ways. Firstly, with a lay audience in mind, it avoids complex technical analysis in favour of clarity and accessibility.

The focused part of this review was deliberately limited in scope to the top 3 major use cases so that these could be adequately explored, but other use cases mentioned in this review also warrant attention and should be examined in future work.

Despite the broad search terms employed, the marked heterogeneity of the subject matter and the cross over between a variety of academic disciplines and industries means that some valid and relevant academic papers may have been excluded. For example, papers written for the financial sector, but with considerable application to the healthcare sector may not have been captured by the search strategy.

Furthermore, given the novel and rapidly evolving nature of this technology, it is likely that current findings will quickly be rendered obsolete, and for this reason ongoing systematic analysis is recommended. In some cases, described prototype solutions may now be in real world use without having been the subject of further reports, and in this manner the review runs the risk of underestimating the current state of the art. The private sector also provides a considerable amount of momentum in the development of blockchain solutions, and some of these private enterprise solutions will have been missed by a review that focuses upon papers produced primarily by the academic community.

7. Conclusions

This review has identified a growing number of blockchain solutions which are directly applicable to orthopaedic practice. Primarily, blockchain offers a means to share EMR data rapidly and securely between patients, surgeons and institutions to support timely and effective care. Subsidiary use cases also extend to the academic orthopaedic community: blockchain supported data systems provide an opportunity for big data research, aggregation of national registry information and provides patients with a chance to engage pro-actively with the research process. IoT integrated blockchain solutions can also be utilised to gather real time patient information, and to effectively secure and validate global supply chains, so that greater numbers of patients have access to quality assured orthopaedic implants and products. Obstacles to the effective adoption of blockchain in orthopaedics include both technical, structural, and cultural hurdles. The majority of reported blockchain solutions have not been adopted into widespread clinical practice. The next phase of blockchain integration will require further real-world testing, followed by large scale implementation. This will require open minded orthopaedic surgeons and institutions who are willing to engage with and adapt to this novel and promising technology.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

The authors declare no conflicts of interest.