Assessing Foot Loads in Continuous Passive Motion (CPM) and Active Knee Joint Motion Devices

Abstract

Background Continuous passive motion (CPM) and active knee joint motion devices are commonly applied after various surgical procedures. Despite the growing use of active motion devices, there is a paucity of data comparing plantar loads between the different mobilization techniques. The aim of this study was to investigate foot loads during knee joint mobilization in continuous passive and active knee joint motion devices and to compare this data to the physiological load of full weight-bearing. Patients/Material and Methods Fifteen healthy participants (7 women and 8 men, 25 ± 3 years, 66 ± 6 kg, 175 ± 10 cm, BMI 21.9 ± 2) were recruited. Plantar loads were measured via dynamic pedobarography using a continuous passive motion device (ARTROMOT-K1, ORMED GmbH, Freiburg, Germany) and an active motion device (CAMOped, OPED AG, Cham, Switzerland), each with a restricted range of motion of 0-0-90° (ex/flex) and free ROM for the knee joint. For the active motion device, cycles were performed at four different resistance levels (0-III). Data were assessed using the pedar® X system (Novel Inc., Munich, Germany), which monitors loads from the foot-sole interface. Force values were compared between motion devices and normal gait, which served as the reference for conditions of full weight-bearing. P-values of < 0.05 were considered statistically significant. Results Normal gait revealed peak forces of 694 ± 96 N, defined as 100 %. The CPM device produced plantar forces of less than 1.5 N. Using the active motion device in the setting of 0-0-90° produced foot loads of < 1.5 N (resistance 0-II) and 3.4 ± 9.3 N with a resistance of III (p < 0.001). Conditions of free ROM resulted in foot loads of 4.5 ± 4.5 N (resistance 0), 7.7 ± 10.7 N (resistance I), 6.7 ± 10.4 (resistance II) and 6.7 ± 6.9 N with a resistance of III (p < 0.001), corresponding to 0.6 %, 1.1 %, 1.0 % and 1.0 % of full weight-bearing, respectively. Conclusion Motion exercises of the knee joint can be performed both with passive and active devices in accordance with strict weight-bearing restrictions, which are often recommended by surgeons. Also, active motion devices can be used when the ankle joint or foot have to be offloaded. Further studies assessing intraarticular joint load conditions have to be performed to confirm the findings obtained in this study.

Pedobarography: A Review on Methods and Practical Use in Foot Disorders

“…For instance, F-scan and Pedar-X systems accept footwear during the examination as they require in-shoe sensors in contrast to barefoot trials in other baropodometers. The methods include optic, piezoelectric, resistive, capacitive techniques based on digital signal inputs [18,[29][30][31][32][33][34][35][36]. The image of the plantar pressure distribution can be presented in several ways.…”

Estimation of Tibiofemoral Joint Contact Forces Using Foot Loads during Continuous Passive Motions

“…Pressure-sensitive insoles have been widely used in both gait assessment [25,26] and the measurement of plantar pressure during rehabilitation [27][28][29]. A general two-dimensional knee model [30,31] and pressure-sensitive insoles were employed in this study to estimate TFFs.…”

Continuous Passive Motion Machine for Elbow Rehabilitation

“…Continuous passive motion (CPM) treatment is widely used in treating patients after various joint surgeries [1]- [8] to avoid joint stiffness and improve patient's recovery. It enhances the knee flexion range [9] and functionality [10] in the initial stage of postoperative for total knee arthroplasty (TKA).…”