Because medical professionals lack the means to monitor exercises performed by patients in their home environment directly, there is a strong case for introducing technological solutions into this domain. They include methods that use wireless inertial sensors, which emit signals recorded and processed by special applications that work with mobile devices. This paper’s aim is (a) to evaluate whether such sensors are suitable for qualitative and quantitative motion analysis, and (b) to determine the repeatability of results over a few recordings. Knee joint activity was analysed using a system of inertial sensors connected through a Wi-Fi network to mobile devices. The tested individuals did eight different activities, all of which engaged the knee joint. Each excercise was repeated three times. Study results did not reveal any statistically significant differences between the three measurements for most of the studied parameters. Furthermore, in almost every case, there were no statistically significant differences between the results of the right and left lower limb (p > 0.05). This study shows that easy use and repeatability of results combined with the feature of quantitative and qualitative analysis make the examined method useful for functional evaluations of the knee joint.

Reduced range of motion is one of the main symptoms of knee osteoarthritis. These deficits are believed to have a negative impact on activities of daily living. The aim of the study was to examine how manual therapy and closed-chain kinematic exercises affect the range of motion in patients with knee osteoarthritis. Sixty-six patients with knee osteoarthritis were recruited and divided into three groups: manual therapy group, exercise group, and control group. The following parameters were evaluated before and after 10 days of rehabilitation: the range of motion in the open and closed kinematic chain using Orthyo sensors, pain intensity using Visual Analogue Scale (VAS), and the subjective functional assessment in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The results indicate an increase in the range of motion after manual therapy in the open chain test and an increase in the possible range of motion in the closed chain test in the exercise group. Both study groups showed significant improvement of WOMAC-assessed function and a significant decrease of VAS-assessed pain following rehabilitation. Manual therapy and exercise affect the range of motion in patients with knee osteoarthritis. When examining the range of motion, it is worth taking into account various biomechanical conditions.

Osteoarthritis of the knee (OAK) is characterized by pain, limitation of joint mobility, and significant deterioration of proprioception resulting in functional decline. This study assessed proprioception in OAK patients following two ten-day rehabilitation programs using the Orthyo® system. Fifty-four study participants with clinical symptoms and radiological signs of OAK were randomly divided into an exercise group (n = 27) or a manual therapy group (n = 27). The control group consisted of 27 volunteers with radiological signs of OAK, but with no clinical symptoms or prior history of rehabilitation. The following parameters were assessed: knee proprioception using inertial sensors and a mobile application, patients’ function using Western Ontario and McMaster Universities osteoarthritis index (WOMAC), and pain intensity using the visual analog scale (VAS). Following rehabilitation, knee proprioception tests did not improve in either study group. Both study groups showed significant improvement of the WOMAC-assessed function (exercise group: p < 0.01, manual therapy group: p = 0.01) and a significant decrease (p < 0.01) of VAS-assessed pain following rehabilitation, but the post-therapy results did not differ significantly between the aforementioned groups. The Orthyo® system provided a quick and accurate assessment of the knee joint position sense. There was no direct relationship between functionality, pain, and proprioception threshold in the knee joint.