Digital health applications from a government-regulated directory of reimbursable health apps in Germany-a systematic review for evidence and bias.

Background: The Digital Healthcare Act, passed in November 2019, authorizes healthcare providers in Germany to prescribe digital health applications (DiGA) to patients covered by statutory health insurance. If DiGA meet specific efficacy requirements, they may be listed in a special directory maintained by the German Federal Institute for Drugs and Medical Devices. Due to the lack of well-founded app evaluation tools, the objectives were to assess (I) the evidence quality situation for DiGA in the literature and (II) how DiGA manufacturers deal with this issue, as reflected by the apps available in the aforementioned directory. Methods: A systematic review of the literature on DiGA using PubMed, Scopus, and Web of Science was started on February 4, 2023. Papers addressing the evidence for applications listed in the directory were included, while duplicates and mere study protocols not reporting on data were removed. The remaining publications were used to assess the quality of the evidence or potential gaps in this regard. Results were aggregated in tabular form. Results: The review identified fourteen relevant publications. Six studies suggested inadequate scientific evidence, five mentioned shortcomings of tools for validating DiGA-related evidence, and four publications described a high potential for bias, potentially influencing the validity of the results. Concerns about limited external generalizability were also raised. Conclusions: The literature review found evidence-related gaps that must be addressed with adequate measures. Our findings can serve as a basis for a plea for a more detailed examination of the quality of evidence in the DiGA context.

Growth and aging in a few phase-separating active matter systems.

Via computer simulations we study evolution dynamics in systems of continuously moving active Brownian particles. The obtained results are discussed against those from the passive 2D Ising case. Following sudden quenches of random configurations to state points lying within the miscibility gaps and to the critical points, we investigate the far-from-steady-state dynamics by calculating quantities associated with structure and characteristic length scales. We also study aging for quenches into the miscibility gap and provide a quantitative picture for the scaling behavior of the two-time order-parameter correlation function. The overall structure and dynamics are consistent with expectations from the Ising model. This remains true for certain active lattice models as well, for which we present results for quenches to the critical points.

[Secure app usage-Evaluation benchmarks for medical apps : Quality aspects for health apps based on 9 key criteria]. / "Secure app usage" ­ Bewertungsmaßstäbe für klinische Applikationen : Qualitätsaspekte für Gesundheits-Apps anhand von 9 Qualitätskriterien.

Smartphones and health apps are an integral part of everyday life. They are increasingly being used for medical purposes. However, there is no fundamental basis or consensus on the evidence on which decisions are made towards a unified digital strategy. Consequently, the understanding of the quality of health apps is only inconsistent and fuzzily defined. The 9 quality criteria presented by the Association of Medical Societies (AWMF)-transparency, appropriateness, risk appropriateness, ethical harmlessness, legal conformity, content validity, technical appropriateness, usability, resource efficiency-serve as a guide for individual and institutionalized quality assessment. The principles are based on a comprehensive compilation of existing (inter-) national standards and evaluation benchmarks. Analogously to usual medical practice, it is also obligatory to conduct one's own research for a suitable app and to weigh up the risks and benefits when using an app.

Evidence of Digital Health Applications from a State-Regulated Repository for Reimbursable Health Applications in Germany.

17 RCTs for 15 digital health applications (DiGA) permanently listed in the state-regulated register were analyzed descriptively for methodological study aspects relevant to evidence analysis. The analysis revealed that several underlying studies had limitations, at least worthy of discussion, in terms of their power concerning sample size, intervention and control group specifications, drop-out rates, and blinding.

Development of Open Backend Structures for Health Care Professionals to Improve Participation in App Developments: Pilot Usability Study of a Medical App.

BACKGROUND: Efficient digitization in medicine still is in its infancy but undeniably has great potential for current and future challenges in health care. Thus far, the rollout of medical apps has not resulted in widespread use of smartphones in the German health care sector-the reasons for this have not been clarified so far. Nevertheless, the lack of user involvement in the development process and content creation might contribute to low acceptance of these products. OBJECTIVE: This study aims to outline an approach to involve medical expertise without any coding knowledge for developing medical app content and functions. METHODS: An end user-operable backend was built. Its usability was evaluated using a usability evaluation test protocol. The results of the usability tests were evaluated by the app development team, and the usability test was repeated for optimizing backend usability. In total, 40 criteria to measure the ease of app usage were defined a priori. The usability test comprised 20 tasks that had to be fulfilled. Usability tasks were analyzed for completion, dropout, and test duration. Due to the COVID-19 pandemic, digital videoconferencing platforms (Zoom and QuickTime Player) were used to complete usability questionnaires. Finally, several backend-based apps for several specialties (infectiology, plastic and reconstructive surgery, and orthopedics) were developed by health care professionals as prototypes. RESULTS: Initial usability testing was conducted with 5 participants (4 men and 1 woman; mean age 39.2, SD 5.97 years). All of them could complete the assigned backend tasks with only a few workflow interruptions and some minor errors. After usability optimization, the workflow completion time decreased from 5.03 minutes to 3.50 minutes, indicating a time saving. The basic backend structure was clear to all test users and the handling was intuitive to learn. Some minor errors in the backend occurred during the test rounds. The apps developed using the aforementioned approach are in clinical use as a proof of concept. CONCLUSIONS: Backends offering operability for medical professionals might have great potential for app development in the mobile health sector. Sophisticated and time-saving usability are pivotal for the acceptance of medical software, as illustrated by the backend-based apps presented herein, which are in clinical use as a proof of concept. Basic interventions are essential and sufficient for adequate usability optimization. Practicable, well-structured software usability evaluation is possible based on the usability evaluation test protocol.

Orthopaedic and trauma surgeons' prioritisation of app quality principles based on their demographic background.

BACKGROUND: Although apps are becoming increasingly relevant in healthcare, there is limited knowledge about how healthcare professionals perceive "quality" in this context and how quality principles that can aid them in assessing health-related apps may be prioritised. The objective was to investigate physicians' views of predefined (general) quality principles for health apps and to determine whether a ranking algorithm applied to the acquired data can provide stable results against various demographic influences and may thus be appropriate for prioritisation. METHODS: Participants of an online survey of members of two German professional orthopaedics associations conducted between 02/12/2019 and 02/01/2020 were asked about their perception of a set of quality principles for health apps (i.e., "practicality," "risk adequacy," "ethical soundness," "legal conformity," "content validity," "technical adequacy," "usability," "resource efficiency," and "transparency"). Structured as a Kano survey, for each principle, there were questions about its perceived relevance and opinions regarding the presence or absence of corresponding characteristics. The available data were evaluated descriptively, and a newly developed method for prioritisation of the principles was applied overall and to different demographic strata (for validation). RESULTS: Three hundred eighty-two datasets from 9503 participants were evaluated. Legal conformity, content validity, and risk adequacy filled ranks one to three, followed by practicability, ethical soundness, and usability (ranks 4 to 6). Technical adequacy, transparency, and resource efficiency ranked last (ranks 7 to 9). The ranking based on the proposed method was relatively stable, irrespective of demographic factors. The principles were seen as essential, with one exception ("resource efficiency"). Only those with little to no interest in digitisation (22/382, 5.8%) rated the nine principles indifferently. CONCLUSIONS: The specified quality principles and their prioritisation can lay a foundation for future assessments of apps in the medical field. Professional societies build upon this to highlight opportunities for digital transformations in medicine and encourage their members to participate.

Proposal of a New Rating Concept for Digital Health Applications in Orthopedics and Traumatology.

BACKGROUND: Health-related mobile applications (apps) are rapidly increasing in number. There is an urgent need for assessment tools and algorithms that allow the usability and content criteria of these applications to be objectively assessed. The aim of this work was to establish and validate a concept for orthopedic societies to rate health apps to set a quality standard for their safe use. METHODS: An objective rating concept was created, consisting of nine quality criteria. A self-declaration sheet for app manufacturers was designed. Manufacturers completed the self-declaration, and the app was examined by independent internal reviewers. The pilot validation and analysis were performed on two independent health applications. An algorithm for orthopedic societies was created based on the experiences in this study flow. RESULTS: "Sprunggelenks-App" was approved by the reviewers with 45 (98%) fulfilled criteria and one (2%) unfulfilled criterion. "Therapie-App" was approved, with 28 (61%) met criteria, 6 (13%) unfulfilled criteria and 12 (26%) criteria that could not be assessed. The self-declaration completed by the app manufacturer is recommended, followed by a legal and technical rating performed by an external institution. When rated positive, the societies' internal review using independent raters can be performed. In case of a positive rating, a visual certification can be granted to the manufacturer for a certain time frame. CONCLUSION: An objective rating algorithm is proposed for the assessment of digital health applications. This can help societies to improve the quality assessment, quality assurance and patient safety of those apps. The proposed concept must be further validated for inter-rater consistency and reliability.

Requirements for an app from the perspective of patients in plastic and reconstructive surgery.

BACKGROUND: Along with the higher availability of Internet, worldwide access and the use of cell phones, the demands of patients for digitalized medical care have increased. METHODS: A questionnaire-based prospective study of 405 patients was conducted to investigate their expectations and requirements of app-based "mHealth" applications. RESULTS: "Behavioral guidance after surgery," "overview of personal findings," and "contact with the treating physician" were the most important factors. In contrast, "exchange with other patients" seemed to be of less importance. CONCLUSION: There is a need for health-oriented apps among patients undergoing plastic and reconstructive surgery, especially with the requirements for individual postoperative care.

Critical behavior in active lattice models of motility-induced phase separation.

Lattice models allow for a computationally efficient investigation of motility-induced phase separation (MIPS) compared to off-lattice systems. Simulations are less demanding, and thus, bigger systems can be accessed with higher accuracy and better statistics. In equilibrium, lattice and off-lattice models with comparable interactions belong to the same universality class. Whether concepts of universality also hold for active particles is still a controversial and open question. Here, we examine two recently proposed active lattice systems that undergo MIPS and investigate numerically their critical behavior. In particular, we examine the claim that these systems and MIPS in general belong to the Ising universality class. We also take a more detailed look on the influence and role of rotational diffusion and active velocity in these systems.

Acceptance, Barriers, and Future Preferences of Mobile Health Among Patients Receiving Trauma and Orthopedic Surgical Care: Paper-Based Survey in a Prospective Multicenter Study.

BACKGROUND: Smartphones have become an essential part of everyday life and it is undeniable that apps offer enormous opportunities for dealing with future challenges in public health. Nevertheless, the exact patient requirements for medical apps in the field of orthopedic and trauma surgery are currently unknown. OBJECTIVE: The aim of this study was to define target groups, evaluate patient requirements, and the potential and pitfalls regarding medical apps specific for patients receiving orthopedic and trauma surgical care. METHODS: A prospective multicenter study was conducted between August 2018 and December 2019 at a German trauma center and 3 trauma surgery/orthopedic practices. A paper-based survey consisting of 15 questions evaluated information regarding smartphone and medical app usage behavior. In addition, suggested app functions were rated using Likert scales. Descriptive statistics and binary log-binomial regression were performed. RESULTS: A total of 1055 questionnaires were included in our statistical analysis. Approximately 89.57% (945/1055) of the patients in this study owned a smartphone. Smartphone ownership probability decreased with every decade of life and increased with higher levels of education. Medical information was obtained via mobile web access by 62.65% (661/1055) of the patients; this correlated with smartphone ownership in regard to age and educational level. Only 11.18% (118/1055) of the patients reported previous medical app usage, and 3.50% (37/1055) of the patients received an app recommendation from a physician. More than half (594/1055, 56.30%) of the patients were unwilling to pay for a medical app. The highest rated app functions were information about medication, behavioral guidelines, and medical record archival. An improved treatment experience was reported through the suggested app features by 71.18% (751/1055) of the patients. CONCLUSIONS: Mobile devices are a widely used source of information for medical content, but only a minority of the population reported previous medical app usage. The main target group for medical apps among patients receiving orthopedic and trauma surgical care tends to be the younger population, which results in a danger of excluding fringe groups, especially the older adults. Education seems to be one of the most important pull factors to use smartphones or a mobile web connection to obtain health information. Medical apps primarily focusing on an optimized patient education and flow of information seem to have the potential to support patients in health issues, at least in their subjective perception. For future target group-oriented app developments, further evidence on the clinical application, feasibility, and acceptance of app usage are necessary in order to avoid patient endangerment and to limit socioeconomic costs.

The Digital Healthcare Act - a Turning Point in the German Digitisation Strategy? / Das Digitale-Versorgung-Gesetz ­ eine Zäsur der deutschen Digitalisierungsstrategie?

The recently ratified Digital Healthcare Act - DVG - has paved the way, among other issues, for the prescription of health apps. The German DVG creates an entitlement to health apps for the very first time. However, this entitlement is initially limited to low-risk medical devices that have been included in the publicly accessible Register for Digital Health Applications by the German Federal Institute for Drugs and Medical Devices. Listing in the register is granted, if the manufacturer has submitted a health app and verified that it meets basic requirements for medical devices and data security as well as positive health care effects. It is questionable, whether the DVG will lead to sustainable improvements in future patient care. In order to pursue this question and align the DGOUC's digitization strategy closely with its basis, an online survey was conducted among the respective members on the DVG's content and its associated opportunities and risks. A total of 461 German-speaking, predominantly male, experienced and elderly physicians in leading positions took part in the survey. In this study, it was shown that the majority of the participating German orthopaedic and trauma surgeons is not familiar with the DVG's contents. Despite a fundamentally positive attitude towards digitization, scepticism about the use of "apps on prescription" and potential risks still prevails at present. The closing of ranks between medicine, IT and the legislature via interdisciplinary expert groups and the involvement of medical societies might be obligatory.

Long-Term Radiographic Changes in Stemless Press-Fit Total Shoulder Arthroplasty.

INTRODUCTION: Stemmed humeral implants have represented the gold standard in total shoulder arthroplasty (TSA) for decades. Like many other joints, the latest trends in TSA designs aim at bone preservation. Current studies have demonstrated that native proximal humeral bone stresses are most closely mimicked by stemless implants. Nevertheless, there are concerns about the long-term performance of stemless designs. The aim of the present study was to evaluate the long-term radiographic changes at the proximal humerus in anatomical stemless press-fit TSA. MATERIALS AND METHODS: Between 2008 and 2010, 48 shoulders in 43 patients were resurfaced using an anatomic stemless shoulder prosthesis (TESS, Biomet). Thirty shoulders in twenty-five patients who were aged 65.7 ± 9.9 (34 to 82) years were available for clinical and radiographic review at a mean follow-up of 94.0 ± 8.9 (78 to 110) months. RESULTS: Radiographic changes of the proximal humerus due to stress shielding were found in 38.4% of the stemless TESS implants. Mild stress shielding accounted for 80% of the observed radiographic changes. Radiographs exhibited stable fixation of the stemless humeral press-fit implant at early and late follow-up. In contrast, radiolucent lines at the glenoid implant were found in 96.1% of the cases. Irrespective of the degree of radiographic changes, clinical scores (VAS, Quick-DASH, Constant score) significantly improved at follow-up. CONCLUSIONS: The anatomic stemless press-fit implant seems to be favorable in terms of implant-related stress shielding. Clinical outcome was not affected by radiographic changes, demonstrating an 8-year clinical performance that seems to be comparable to conventional stemmed TSA.

A small series of pole sport injuries.

Pole sport is a relatively new athletic sport that is gaining increasing popularity and for which national and international championships are held. It evolved from pole dance and harbours the risk of falls from heights of up to three metres. Currently, no studies on pole sport injuries are available. This is the first description of a small series of five pole sport injuries. A retrospective review of the case histories and radiological findings was performed, and in addition, a follow-up interview was carried out. All the patients were female and had a mean age of 27.2 years. Most injuries were located in the head, neck or spine. The use of proper training equipment like landing mats and grip aids could probably reduce accidents.

Smartphone and App Usage in Orthopedics and Trauma Surgery: Survey Study of Physicians Regarding Acceptance, Risks, and Future Prospects in Germany.

BACKGROUND: In the course of digitization, smartphones are affecting an increasing number of areas of users' lives, giving them almost ubiquitous access to the internet and other web applications. Mobile health (mHealth) has become an integral part of some areas of patient care. In contrast to other disciplines, routine integration of mobile devices in orthopedics and trauma surgery in Germany is still in its infancy. OBJECTIVE: This study aimed to investigate physicians' current state of opinion regarding acceptance, future prospects, and risks of medical apps in the field of orthopedics and trauma surgery in Germany. METHODS: A web-based survey among orthopedics and trauma surgeons in German university hospitals on the use of medical apps in everyday clinical practice was conducted between September 2018 and February 2019. The survey consisted of 13 open- and closed-ended or multiple-choice questions. A logistic regression analysis was performed to ascertain the effects of interindividual characteristics on the likelihood of participants' app and smartphone usage behavior. RESULTS: A total of 206 physicians participated in the survey. All of the participants (206/206, 100%) owned a smartphone, and 79.1% (159/201) used the device, while 64.7% (130/201) used apps regularly in everyday clinical practice. Medical apps were perceived as beneficial, given their substantial future promise, by 90.1% (181/201) of the participants. However, 62.5% (120/192) of the participants were not satisfied with the current supply of medical apps in app stores. Desired specifications for future apps were "intuitive usability" (167/201, 83.1%), "no advertising" (145/201, 72.1%), and "free apps" (92/201, 45.8%). The attributes "transparent app development and app sponsoring" (75/201, 37.3%) and the existence of an "easy-to-understand privacy statement" (50/201, 24.9%) were of minor relevance. The majority of the participants (162/194, 83.5%) considered that future apps in the field of "medical research" would provide the greatest benefit. The greatest predicted risks were "data misuse" (147/189, 77.8%), "usage of untrustworthy apps" (135/189, 71.4%), and "alienation from patients" (51/189, 27.0%). Increasing age was significantly associated with a reduction in the likelihood of regular smartphone (odds ratio [OR] 0.91, 95% CI 0.86-0.97; P=.002) and app (OR 0.90, 95% CI 0.85-0.96; P=.001) usage, while the medical profession grade had no significant impact on the usage behavior. CONCLUSIONS: The study demonstrates that young German doctors in orthopedics and trauma surgery already use smartphones and apps in everyday clinical practice. Medical apps are considered to play an important role in the future. However, a significant discrepancy exists between the supply and demand of mHealth applications, which creates a legal and ethical vacuum with regard to data protection.

[Digitalization in orthopedics and trauma surgery: current status of clinical and practical aspects 2020]. / Digitalisierung in Orthopädie und Unfallchirurgie: Stand 2020 in Klinik und Praxis.

This article deals with the current state mid-2020 in the clinical and practical aspects from the perspective of orthopedics and trauma surgery. The risks, difficulties, potentials and options are discussed in detail. The following topics are specifically debated: infrastructure of telematics, apps and mobile health, online video consultation, electronic medical records and data protection. The advantages and disadvantages and the current state of each topic in the special case of orthopedics and trauma surgery are discussed. Additionally, seven meaningful examples from the field of digital applications are named. A survey of members of the Professional Association of Orthopedic and Trauma Surgeons (BVOU) is described and analyzed. In a concluding perspective the current hurdles and future topics that need clarification are addressed.

Correction: Analysis of Secure Apps for Daily Clinical Use by German Orthopedic Surgeons: Searching for the "Needle in a Haystack".

[This corrects the article DOI: 10.2196/17085.].

Analysis of Secure Apps for Daily Clinical Use by German Orthopedic Surgeons: Searching for the "Needle in a Haystack".

BACKGROUND: It is undeniable that appropriate smartphone apps offer enormous opportunities for dealing with future challenges in orthopedic surgery and public health, in general. However, it is still unclear how the apps currently available in the two major app stores can be used in daily clinical routine by German orthopedic surgeons. OBJECTIVE: This study aimed to gain evidence regarding the quantity and quality of apps available in the two major app stores and their suitability for use by orthopedic surgeons in Germany. METHODS: We conducted a systematic, keyword-based app store screening to obtain evidence concerning the quantity and quality of commercially available apps. Apps that met the inclusion criteria were evaluated using the app synopsis-checklist for users and the German Mobile App Rating Scale for secure use, trustworthiness, and quality. RESULTS: The investigation revealed serious shortcomings regarding legal and medical aspects. Furthermore, most apps turned out to be useless and unsuitable for the clinical field of application (4242/4249, 99.84%). Finally, 7 trustworthy and high-quality apps (7/4249, 0.16%) offering secure usage in the daily clinical routine of orthopedists were identified. These apps mainly focused on education (5/7). None of them were CE (Conformité Européenne) certified. Moreover, there are no studies providing evidence that these apps have any positive use whatsoever. CONCLUSIONS: The data obtained in our study suggest that the number of trustworthy and high-quality apps on offer is extremely low. Nowadays, finding appropriate apps in the fast-moving, complex, dynamic, and rudimentarily controlled app stores is most challenging. Promising approaches, for example, systematic app store screenings, app-rating developments, reviews or app libraries, and the creation of consistent standards have been established. However, further efforts are necessary to ensure that these innovative mobile health apps not only provide the correct information but are also safe to use in daily clinical practice.

Synovial bone sialoprotein indicates aseptic failure in total joint arthroplasty.

BACKGROUND: Until today, a reliable diagnostic discrimination between periprosthetic joint infections (PJI) and aseptic failure (AF) after total joint arthroplasty (TJA) remains challenging. Nearly all recent research focused on synovial markers to be elevated in PJI rather than in AF patients. In this study, synovial bone sialoprotein (sBSP) was investigated in PJI and AF arthroplasty patients before revision surgery. METHODS: sBSP and C-reactive protein (CRP) were determined in synovial fluid samples of PJI (n = 13) patients fulfilling the MSIS criteria and AF (n = 25) patients. Beside descriptive analysis and comparison, computed statistics determined the area under the receiver operating characteristics curve (AUC) to evaluate the discrimination ability of the tested synovial markers. RESULTS: In patients with PJI according to the MSIS criteria, mean sBSP was significantly lower: 14.8 ng/ml (95% CI 5.5-24.1) vs. 38.2 ng/ml in the AF group (95% CI 31.1-45.3), p ≤ 0.001. Conversely, mean sCRP was significantly higher in PJI patients: 8.4 µg/ml (95% CI 0-17.2) vs. 1.8 µg/ml in the AF group (95% CI 0.9-2.8), p = 0.032. The AUC of sCRP in PJI patients was 0.71. The AUC of sBSP in AF revision arthroplasty patients was 0.83. The detection of osteolyses was not associated with higher sBSP concentrations. CONCLUSIONS: Considering the MSIS criteria, significantly higher sBSP concentrations were found in synovial fluid samples of AF compared to PJI patients. sCRP showed only fair, sBSP good discrimination potential. If it is not clear whether PJI is present or not, sBSP may be considered as an add-on synovial marker.

Results of advanced core decompression in patients with osteonecrosis of the femoral head depending on age and sex-a prospective cohort study.

BACKGROUND: Core decompression is a common surgical technique to treat osteonecrosis of the femoral head. The aim of this study is to evaluate the effect of the parameters "age" and "sex" on the outcome of this type of treatment. METHODS: A prospective cohort study was performed. Eighty-six osteonecrotic hips with a mean follow-up of 32.5 months (± 24.8) after advanced core decompression were analysed regarding age- and sex-dependent treatment failure. Additionally, the modified Harris Hip Score and Numeric Rating Scale were compared regarding the parameters age and sex. RESULTS: The mean hip survival of the male participants was 51.3 months (39.4% treatment failure), whereas females presented a longer, thus not significant, mean survival of 61.4 months (30% therapy failure; p = 0.48). The further evaluation revealed significantly better survival in the patients aged < 40 years (mean survival 66.09 months, 16% treatment failure) in comparison to those aged ≥ 40 years (mean survival 50.14 months, 46% therapy failure; p = 0.03). The modified Harris Hip Score and Numeric Rating Scale results of patients whose treatment did not fail during the study period were similar, irrespective of the patient's sex or age. CONCLUSIONS: The study shows that the number of therapy failures is significantly higher in older patients, with 40 years of age marking the borderline. Patients' sex does not seem to affect the outcome of treatment, and postoperative clinical scores appear to be identical with individuals not affected by therapy failure. Since age and sex are unalterable parameters, the study helps to provide valuable predictions regarding the chances of long-term hip survival after treatment of osteonecrosis.

A Possible Mobile Health Solution in Orthopedics and Trauma Surgery: Development Protocol and User Evaluation of the Ankle Joint App.

BACKGROUND: Ankle sprains are one of the most frequent sports injuries. With respect to the high prevalence of ankle ligament injuries and patients' young age, optimizing treatment and rehabilitation is mandatory to prevent future complications such as chronic ankle instability or osteoarthritis. OBJECTIVE: In modern times, an increasing amount of smartphone usage in patient care is evident. Studies investigating mobile health (mHealth)-based rehabilitation programs after ankle sprains are rare. The aim of this study was to expose any issues present in the development process of a medical app as well as associated risks and chances. METHODS: The development process of the Ankle Joint App was defined in chronological order using a protocol. The app's quality was evaluated using the (user) German Mobile App Rating Scale (MARS-G) by voluntary foot and ankle surgeons (n=20) and voluntary athletes (n=20). RESULTS: A multidisciplinary development team built a hybrid app with a corresponding backend structure. The app's content provides actual medical literature, training videos, and a log function. Excellent interrater reliability (interrater reliability=0.92; 95% CI 0.86-0.96) was obtained. The mean overall score for the Ankle Joint App was 4.4 (SD 0.5). The mean subjective quality scores were 3.6 (surgeons: SD 0.7) and 3.8 (athletes: SD 0.5). Behavioral change had mean scores of 4.1 (surgeons: SD 0.7) and 4.3 (athletes: SD 0.7). The medical gain value, rated by the surgeons only, was 3.9 (SD 0.6). CONCLUSIONS: The data obtained demonstrate that mHealth-based rehabilitation programs might be a useful tool for patient education and collection of personal data. The achieved (user) MARS-G scores support a high quality of the tested app. Medical app development with an a priori defined target group and a precisely intended purpose, in a multidisciplinary team, is highly promising. Follow-up studies are required to obtain funded evidence for the ankle joints app's effects on economical and medical aspects in comparison with established nondigital therapy paths.