A prospective, quasi-experimental study was performed. Patients were recruited from the INR Orthopedic Rehabilitation Outpatient Clinic and were eligible for inclusion if they were >18 years of age, had a diagnosis of partial RC tears (clinical and by ultrasound), had symptoms for less than 6 months evolution time, had not received rehabilitation treatment previously and were not candidates for initial surgical treatment. An important criterion was that patients should be residing outside the Mexico City or should have encountered difficulty in accessing the INR installation due to personal reasons or distance. No limits were placed on the gender of the patient.

Subjects confirmed that they possessed a computer with Windows 7 or a more recent operating system, as well as a camera and internet connection, and that either a caregiver and/or the patient knew how to operate the equipment. Patients with complete tears or full thickness tears, calcific tendonitis, or a history of previous surgical events were excluded from the study.

A clinical evaluation was performed that included the following: a clinical interview, physical exploration, and administration of the Constant-Murley (CM) scale. Patients were invited to participate in the study, and they signed the informed consent form and gave permission to use and publish their images and videos for the purpose of the project. Later the same day, a shoulder ultrasound was performed to confirm and evaluate the degree, type, and location of the injury.

For the assessment of muscle strength, a dynamometer of the Braunker brand was used, and patients performed concentric isotonic contraction of the injured shoulder during flexion and abduction in the scapular plane; the results were reported in pounds.

Based on this evaluation, a physician specialized in Physical Medicine and Rehabilitation assigned the TR program, choosing the platform's most appropriate videos or instructions for each patient. It included the following: thermotherapy; movement; stretching, and strengthening. Patients, along with a companion, were personally instructed on the use of the platform for 1 hour. During this session, their questions were answered regarding how to access and use the system, perform their prescribed therapies, interact with therapists, receive feedback, and upload their videos onto the platform.

A user name and password were provided to the patient so that they could access the virtual site. Patients were expected to devote approximately 30 minutes per day, 5 days a week, to the program.

Each time the patients connected to the program, they had the possibility of gaining general information on their condition, becoming more familiar with care activities or modifications in their environment, checking the method for performing physical therapy through individually assigned videos, and receiving feedback from health professionals in order to improve the manner in which they perform their therapy. All accesses, length of time spent, and logout time were recorded in the system.

As part of the program and feedback, twice a week, the patients were asked to record how they were performing their therapy and to send the video to the platform. This material was evaluated by physicians and therapists, and according to the patient's performance, written feedback was sent to each patient with the same frequency within the system (Fig. 4).

Functional evaluations were performed at baseline and at 1, 2, 3, and 6 months. At each evaluation, the physician modified the prescribed therapy in the system so that the patients could progress further based on their individual symptomatology, including types of exercises, techniques, and number of sets or repetitions. At the end of the 3-month evaluation, the patients continued with their individual therapy programs with monthly feedback on the platform until month 6.

Outcomes comprised pain measured by the visual analog scale (VAS) and functionality on the CM scale (which includes the qualitative measurement of pain and quantitative movement and strength through the use of a dynamometer).

Sample size was not calculated as this was a preliminary study due to the technical difficulties that could arise during the initial use of the system.

Descriptive statistics were employed to summarize the data, using medians and ranges as central tendency and dispersion measurements. In order to confirm the hypothesis, non-parametric tests were utilized, assuming a non-normal distribution. Wilcoxon range tests were used for (quantitative) variables of functional outcome, comparing two related samples, or the Friedman test was employed to compare various related samples at different time periods. Fisher exact test was utilized to compare and measure nominal variables.

The protocol was registered with the INR Research Committee and it followed the institute's ethical guidelines, Good Clinical Practice (GCP), the Helsinki Declaration, and the Health Research Regulations appearing in the Mexican General Law of Health.

The eye tracking system allowed for measuring the time and location of the images and buttons, and deciding the most appropriate location on the screen, for the buttons, text and images for the system. Seven volunteers rated the use of the system. With respect to access to the platform, 4 (57.1%) subjects rated it as excellent and 3 (42.9%) subjects rated it as very good. With respect to the use of the platform, 6 (85.7%) subjects rated it as excellent and 1 (14.3%) subject rated it as very good. All subjects received a post-use platform feedback and 7 (100%) subjects rated it as excellent and recommended its use by others.

A total of 20 patients were recruited, of which 5 patients were excluded for having complete or massive tears, 2 patients were excluded for having calcific tendonitis, and 2 patients were excluded for being candidates for initial surgery. For the final analysis, a total of 11 patients were included, 5 women and 6 men, whose median age was 55 years (range, 42–68 years). The median symptom evolution time was 3.5 months.

None of the patients engaged in work or leisure activities that were described as risk factors for shoulder injuries.

With respect to the injury type, 7 patients had a sole supraspinatus injury, 2 patients had a supraspinatus and infraspinatus injury, and 2 patients had a supraspinatus and subscapularis injury. Six patients presented with injuries to their dominant arm, and 5 patients presented with injuries to their non-dominant arm.

All patients completed their initial evaluation, as well as follow-up visits; none of the patients were lost to follow-up.

Pain outcomes on the VAS are depicted in Table 1. Qualitative pain measurement according to the CM scale at baseline revealed that 85% of the patients had moderate pain and 15% of the patients had severe pain; at 1 month, 44% of the patients had no pain, 22% of the patients had moderate pain, and 22% of the patients had minimal pain, and at 3 and 6 months, 46% of the patients remained free of pain and 54% of the patients had minimal pain (p<0.01).

The evaluation of daily living and work activities according to the CM scale demonstrated that 100% of the patients had moderate limitation, but in evaluations at 1, 3, and 6 months, 68% of the patients remained without limitations (p<0.01).

Evaluation of movement of the flexors and abductors on the scale is presented in Figs. 5 and 6. With respect to muscle strength, progression over time is presented in Table 2. Total classification with the baseline CM scale and follow-ups is illustrated in Table 3.

All patients reported adequate acceptability of the platform and they would recommend the said platform to others in the future.