This study aimed to evaluate the reliability of the RSQ Motion sensor and its validity against the Propriometer and electronic goniometer in measuring the active range of motion (ROM) of the shoulder. The study included 15 volunteers (mean age 24.73 ± 3.31) without any clinical symptoms with no history of trauma, disease, or surgery to the upper limb. Four movements were tested: flexion, abduction, external and internal rotation. Validation was assessed in the full range of active shoulder motion. Reliability was revised in full active ROM, a fixed angle of 90 degrees for flexion and abduction, and 45 degrees for internal and external rotation. Each participant was assessed three times: on the first day by both testers and on the second day only by one of the testers. Goniometer and RSQ Motion sensors showed moderate to excellent correlation for all tested movements (ICC 0.61–0.97, LOA < 23 degrees). Analysis of inter-rater reliability showed good to excellent agreement between both testers (ICC 0.74–0.97, LOA 13–35 degrees). Analysis of intra-rater reliability showed moderate to a good agreement (ICC 0.7–0.88, LOA 22–37 degrees). The shoulder internal and external rotation measurement with RSQ Motion sensors is valid and reliable. There is a high level of inter-rater and intra-rater reliability for the RSQ Motion sensors and Propriometer.

The invention of inertial measurement units allowed the construction of sensors suitable for human motion tracking that are more affordable than expensive optical motion capture systems, but there are a few factors influencing their accuracy, such as the calibration methods and the fusion algorithms used to translate sensor readings into angles. The main purpose of this study was to test the accuracy of a single RSQ Motion sensor in comparison to a highly precise industrial robot. The secondary objectives were to test how the type of sensor calibration affects its accuracy and whether the time and magnitude of the tested angle have an impact on the sensor’s accuracy. We performed sensor tests for nine repetitions of nine static angles made by the robot arm in eleven series. The chosen robot movements mimicked shoulder movements in a range of motion test (flexion, abduction, and rotation). The RSQ Motion sensor appeared to be very accurate, with a root-mean-square error below 0.15°. Furthermore, we found a moderate-to-strong correlation between the sensor error and the magnitude of the measured angle but only for the sensor calibrated with the gyroscope and accelerometer readings. Although the high accuracy of the RSQ Motion sensors was demonstrated in this paper, they require further study on human subjects and comparisons to the other devices known as the gold standards in orthopedics.

Background: Knee osteoarthritis (OA) is a common, chronic, progressive and degenerative disease which affects patients’ quality of life and may cause disability and social isolation. OA is a huge economic burden for the patient and a large strain for the whole healthcare system. Articular cartilage has a small potential to repair, with progressively more clinicians emphasizing cellular therapy. Subcutaneous fat tissue in human body is a large reservoir of mesenchymal stem cells (MSCs) and is been harvested in minimally invasive, simple procedure. The purpose of this study was to define a specific group of patients with knee osteoarthritis, who are the most likely to benefit from the treatment with intra-articular injection of an autologous adipose tissue (AAT). Methods: From 2016 to 2018, 59 symptomatic bilateral and unilateral knee OA patients were treated with a single intra-articular (IA) injection of an autologous adipose tissue (AAT). Before the treatment and at the follow-up, the participant was asked to fulfill the Knee Injury and Osteoarthritis Outcome Score (KOOS), the International Knee Documentation Committee 2000 (IKDC 2000), The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Health Questionnaire EQ-5D-5L and to quantify the pain in the affected joint with a Numeric Rating Scale (NRS). Moreover, the patients were asked to: (i) assess their satisfaction with the effects of the conducted treatment: from 0 (unsatisfied) to 10 (very satisfied), (ii) describe the rehabilitation, if it was performed (supervised or individual and duration in weeks) and (iii) indicate any additional treatment applied, like IA injections of hyaluronic acid (HA) or platelet-rich plasma (PRP), knee arthroscopy, partial or total knee arthroplasty (TKA) at the follow-up. Results: The mean age of 37 participants (16 males and 21 females) included into statistical analysis was 57.78 ± 7.39 years, the mean BMI was 31.30 ± 7.51. The questionnaires were fulfilled after the average follow-up time of 27 ± 6.5 months. A significant difference (p < 0.05) compared with the baseline, was observed in pain [NRS], WOMAC, KOOS index, pain, symptoms, ADL, Sport and Rec, QoL, EQ-5D-5L index. The satisfaction in the whole group was 6.16 ± 3.07. There was no significant difference between satisfied and unsatisfied patients in BMI and pain [NRS] at the baseline. 6 out of 7 patients with stage IV in K-L were unsatisfied with the effects of the treatment with AAT. Discussion: The main conclusion of this study is that the patients with stage II of the knee OA with normal BMI are were most likely to benefit from IA injection of AAT, in contrast to the patients with stage IV, who will not beware not satisfied with the effectiveness of this kind of treatment. There were no adverse events reported at the donor site as well as in the treated knee joints.

Background: Inertial measurement units (IMUs) represent a relatively new and promising method for motion analysis. Their main advantages include small size and portability, combined with the use of advanced technologies. To date, few studies have investigated the application of these devices for proprioception assessment, and none have focused specifically on the elbow joint. Therefore, the aim of our study was to assess reliability and validate the protocol of elbow proprioception evaluation using inertial motion sensors. Methods: Twenty healthy participants underwent active and passive proprioception assessments based on joint position sense (JPS). Two researchers independently performed evaluation. The analyzed data was the error of reproduction of joint position (ERJP). IMU (RSQ Motion sensors) were used for angular joint position assessment and validated against Biodex System 4. Results: Inter-rater reliability for passive proprioception was good, with a Kendall’s coefficient of 0.77 (p < 0.05) for both RSQ Motion sensors and BIODEX, while active proprioception measured with RSQ Motion sensors showed slightly lower reliability (Kendall’s coefficient of 0.66, p < 0.05). Intra-rater reliability had similar results, with Kendall’s coefficients of 0.74 for passive BIODEX proprioception examination, 0.75 for passive RSQ Motion sensor testing and 0.65 for active proprioception (p < 0.05) measured with RSQ Motion sensors. The Bland–Altman plot revealed an equal distribution of results, which were within the limits of agreement (LoA). Conclusions: These results suggest proprioception assessment by JPS using inertial motion sensors is reliable and valid. It is an easy to use, light, portable, and inexpensive alternative for proprioception assessment, although further research in diverse clinical settings is needed.

Background: Inertial measurement units (IMUs) represent a relatively new and promising method for motion analysis. Their main advantages include small size and portability, combined with the use of advanced technologies. To date, few studies have investigated the application of these devices for proprioception assessment, and none have focused specifically on the elbow joint. Therefore, the aim of our study was to assess reliability and validate the protocol of elbow proprioception evaluation using inertial motion sensors. Methods: Twenty healthy participants underwent active and passive proprioception assessments based on joint position sense (JPS). Two researchers independently performed evaluation. Analyzed data was error of reproduction of joint position (ERJP). IMU (RSQ Motion sensors) were used for angular joint position assessment and validated against Biodex System 4. Results: Inter-rater reliability for passive proprioception was good, with a Kendall’s coefficient of 0.77 (p < 0.05) for both RSQ Motion sensors and BIODEX, while active proprioception measured with RSQ Motion sensors showed slightly lower reliability (Kendall’s coefficient of 0.66, p < 0.05). Intra-rater reliability had similar results, with Kendall’s coefficients of 0.74 for passive BIODEX proprioception examination, 0.75 for passive RSQ Motion sensor testing and 0.65 for active proprioception (p < 0.05) measured with RSQ Motion sensors. Bland-Altman plot revealed equal distribution of results, which were within the limits of agreement (LoA). Conclusion: These results suggest proprioception assessment by JPS using inertial motion sensors is reliable and valid. Easy to use, light, portable, and inexpensive alternative for proprioception assessment, although further research in diverse clinical settings is needed.