Continuous Passive Motion Device Research Articles

The Use of Generative Design Methods to Reduce the Parameters of an Actuator Used in the Positioning System of a Continuous Passive Motion (CPM) Device

This paper presents the results of a computer optimising a multibody system using Generative Design methods to select a lower-cost actuator that meets process requirements with its parameters. Optimisation was performed to reduce the mass of the motion apparatus components of the author’s CPM device, used for the rehabilitation of patients after knee arthroscopy and total or partial knee replacement. An analysis of the kinematics and dynamics of the multibody mechanism, based on a virtual model, was carried out to identify the requirements for selecting an actuator. The main components of the motion apparatus mechanism were subjected to a series of numerical analyses using selected CAD/CAE tools, with the assumed criterion of varying material and component shapes to ensure that the required strength and accuracy of the mechanism links were maintained, assuming the same functionality. The results of the numerical analyses will be the basis for the selection of the optimum solution, for which a new, lower-cost actuator will be selected.

Effects of an Early Exercise Program with Cryotherapy on Range of Motion, Pain, Swelling, and Gait in Patients with Total Knee Arthroplasty: A Randomized Controlled Trial.

Background: This study aimed to investigate the effects of cryotherapy on range of motion, pain, swelling, and gait in patients who underwent total knee arthroplasty. Methods: Forty-three patients who underwent TKA (total knee arthroplasty) and met the inclusion criteria were randomly divided into two groups. The experimental (n = 21) and control (n = 22) groups underwent cryotherapy and non-cryotherapy treatments, respectively, six times a week for two weeks, and once each before and after exercise for 3 min. Both groups followed a similar initial rehabilitation exercise program using a continuous passive motion device. Results: The results showed a significant difference in knee flexion range of motion, pain, edema, and 10 MWT comparisons from pre- to post-test (p < 0.001). The above values were also significantly different in the comparison between the two groups (p < 0.05). Conclusions: Therefore, this study confirmed that an initial rehabilitation exercise program accompanied by cryotherapy could be an effective intervention method for range of motion, pain, edema, and walking in patients undergoing total knee arthroplasty.

Prototype of a Continuous Passive Motion device for shoulder rehabilitation

Continuous Passive Motion - CPM - is a therapeutic method that provides fast and safe patient rehabilitation. Considering the fact that the equipment performs the movement along with the patient, who also does it but passively, this treatment procedure can immediately be applied in the postoperative care period. Although this technique makes recovery faster, as strains will be spared from ligaments, muscles and tendons, not all clinics can offer CPM therapy due to its high cost. Bearing in mind the existence of such equipment that performs the aforementioned motion, the objective of this work was the development and manufacture of a prototype device for continuous passive shoulder movement, with costs reduced to an approximate value of USD$730.00 compared to the average price in the market which is around USD$1510.00. This difference in values would make it affordable for a greater majority of clinics and offices to purchase them and, thus, promote the accelerated timely recovery of the limb after operation, for a larger number of patients, allowing these patients to return to their daily tasks in shorter period of time. For the execution of the prototype, specific mechanical manufacturing methods, such us turning, milling and welding of materials, were applied in order to make the equipment safe and effective, provide comfort for the patient and, above all, make the device affordable for most physiotherapy clinics. The material used for the production was stainless steel, cables, pulleys, tilting automation kit and inductive sensors.

A Prototype Continuous Passive Motion Device Compatible with the Hinged Elbow Ilizarov Fixator

Background. Joint stiffness is a frequent concern in trauma or surgery of the elbow joint. Early resumption of elbow joint motion is said to limit the complication of stiffness. The Hinged Elbow Ilizarov Fixator has been reported to be useful in the management of elbow dislocations. However, early range of motion is not consistent in these cases since elbow movement were done only through patient-initiated exercises. The use of a continuous passive motion (CPM) device can potentially resolve this issue. However, presently available continuous passive motion devices for the elbow are not compatible with the Hinged Elbow Ilizarov Fixator.Objective. The objective of the study is to determine the feasibility of using a specially designed continuous passive motion device on a Hinged Elbow Ilizarov Fixator as applied in a cadaver simulation model.Methods. A Hinged Elbow Ilizarov Fixator was fixed in the elbow of a Thiel-preserved cadaver. The specially designed continuous passive motion device was applied.Results. Test run showed sufficient continuous flexion-extension motion not accompanied by dislocation, subluxation, or disruption of the elbow joint. A point of stress in the current prototype was noted at the motor-screw interface. Limitations in programming and control were also noted.Conclusion. A continuous passive machine adopted to the Hinged Ilizarov Fixator is a viable device. Furtherimprovement in the design of the motor-screw interface needs to be made. Further improvement in programming and control are needed. Likewise, study on the safety and service life of the CPM device needs to be done.

The influence of early virtual reality intervention on pain, anxiety, and function following primary total knee arthroplasty

BackgroundTotal knee arthroplasty (TKA) is one of the most popular surgeries in the orthopedic field. One of the reasons for a failed TKA is pain and difficulty to return to normal function. A pain control method that is becoming more and more popular is the use of virtual reality (VR). We aimed to examine VR intervention in the immediate post-operative physiotherapy following TKA. MethodsThis prospective randomized-controlled study recruited a total of 55 patients undergoing primary TKA in a single institute, operated by three surgeons. They were assigned either study group or control group. Both groups were treated with conventional physiotherapy and CPM equipment (Continuous passive motion device), the study group received additional VR modality. Both groups completed a series of questionnaires prior and after the intervention: State-Trait Anxiety Inventory (STAI) questionnaire (used to diagnose anxiety), Visual analog scale (VAS) for pain and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) (knee function score). ResultsThe average age was 70 years-old with equal distribution of male and female. Both groups showed a decrease in pain and anxiety following the intervention (p value < 0.05) but there was no difference between the groups (p value > 0.05 for all parameters). The was no difference in the WOMAC scores in the six-month post-operative examination between groups (p-value = 0.653). ConclusionsVirtual reality intervention in the immediate post-operative period following total knee arthroplasty decrease pain and anxiety but did not influence the pain, anxiety, and long-term function results more than conventional physiotherapy.

PhysiCan - a device for automatic CPM exercises implementation over canines: Design and analysis

Continuous Passive Motion (CPM) devices have been used to assist physicians conducting human rehabilitation; however, similar machines specific for canine rehabilitation have not been found in the reviewed literature. This research performed a physical analysis of the hind limb of dogs to design a device for implementing automated CPM exercises. The device proved to comply with the guidelines to perform CPM exercises, allowing a proper setting of parameters to generate rehabilitation routines customized for different rehabilitation requirements. Also, an electromyography acquisition module was incorporated into the system, with surface electrodes to visualize and provide feedback to the user for muscle activation. Limitations were encountered with a range of motion of 80° and an error of approximately 2% for angular position accuracy.

An Inverse Dynamics-Based Control Approach for Compliant Control of Pneumatic Artificial Muscles

Rehabilitation is an area of robotics in which human–robot collaboration occurs, requiring adaptation and compliance. Pneumatic artificial muscles (PAM) are soft actuators that have built-in compliance making them usable for rehabilitation robots. Conversely, compliance arises from nonlinear characteristics and generates obstructions in modeling and controlling actions. It is a critical issue limiting the use of PAM. In this work, multi-input single-output (MISO) inverse modeling and inverse dynamics model learning approaches are combined to obtain a novel nonlinear adaptive control scheme for single PAM-actuated 1-DoF rehabilitation devices, for instance, continuous passive motion (CPM) devices. The objective of the proposed system is to bring an alternative solution to the compliant operation of PAM while performing exercise trajectories, to satisfy requirements such as larger range of motion (ROM) and adaptability to external load impedance variations. The control system combines the operation of a nonlinear autoregressive network with exogenous inputs (NARX)-based inverse dynamics estimator used as a global range controller and cascade PIDs for local position and pressure loops. Implementation results demonstrated the efficacy of the introduced method in terms of compliant operation for dynamic external load variations as well as a stable operation in case of impulsive disturbances. To summarize, a simple but efficient method is illustrated to facilitate the common use of PAM.

Prototype of a Continuous Passive Motion Device for the Knee Joint with a Function of Active Exercise

In this study, an active exercise function was added to a continuous passive motion device, which is widely used in rehabilitation therapy for function enhancement. The objective is to reduce physical overwork on the part of physical therapists and promote self-rehabilitation in patients. Impedance control based on position control was applied to provide active exercise load. Various active exercise loads are required to reproduce daily life muscle activity. Accordingly, a friction load model was introduced in the impedance control system. The effects of increasing the types of active exercise loads were evaluated by analysis of muscle activity during experimental tests, and a new muscle activity that could not be attained by the conventional spring-mass-damper load model was confirmed.

Use of continuous passive motion device after arthroscopic hip surgery decreases post-operative pain: A randomized controlled trial

BackgroundWe sought to determine whether continuous passive motion (CPM) usage improves outcomes following arthroscopic hip surgery involving acetabular labral repair. Our hypothesis is that CPM usage reduces pain and pain medication use and improves quality of life in individuals who undergo hip arthroscopy. MethodsWe created a randomized controlled trial consisting of 54 patients who underwent arthroscopic acetabular labral repair. Patients were randomized to two groups, one with CPM use post-operatively and one without. Primary outcomes measured were pain level, patient satisfaction, and quality of life. Parameters used to measure these outcomes were self-reported pain scores on Likert scale, frequency of analgesic medication use, and self-reported scores on Hip Outcome Score Activity of Daily Living (HOS ADL). These parameters were compared between the two randomized groups using t-test for statistical analysis. ResultsThere was no statistical difference between the treatment and control groups in terms of patient characteristics. There was no statistical difference between the two groups in terms of HOS ADL scores, although the patients in the control group demonstrated a trend toward higher HOS ADL scores. The patients in the CPM group had a statistically significant decrease in pain levels after surgery compared to patients in the control group. The total morphine equivalent dose consumed in the first two post-operative weeks was higher in the control group compared to the CPM group, although this difference was not statistically significant. ConclusionsUse of CPM resulted in lower pain level scores in patients after hip arthroscopy. Although there is no statistical difference in quality of life or quantity of analgesics consumed post-operatively, patients who used CPM tended to have lower HOS ADL scores (which is desirable) and less consumption of pain medication. A study with a larger sample of patients might elucidate more differences between the two groups. Level of EvidenceII, therapeutic.

Analysis of Long-Term Outcomes Following Surgical Contracture Release of the Elbow: A Case Series.

BackgroundElbow contracture is a debilitating condition with an incidence ranging from as low as almost 1% to as high as 20% and results in significant limiting consequences on a patient’s activities of daily living (ADLs). Postoperative rehabilitation is important in maintaining the range of motion and sustaining an improved range of motion. The purpose of this study was to evaluate the long-term results of elbow contracture release surgery and the effect of an occupational therapy/physical therapy (OT/PT)-guided, self-directed rehabilitation program following surgery, without the use of continuous passive motion (CPM) devices.MethodsWe enrolled patients who had undergone elbow contracture release surgery from 2005 to 2016 at a single institution under the senior author. The evaluation included objective measurements of range-of-motion, strength, and neurological sensory testing. Provocative testing of the elbow and hand was performed. American Shoulder and Elbow Surgeons-elbow (ASES-e), Simple Shoulder Test-elbow (SST-e), Disabilities of the Arm and Shoulder (DASH), Mayo Elbow Performance Index (MEPI), Short Form-36 (SF-36), and an investigator questionnaire were completed.ResultsWe enrolled 19 patients, six female and 13 male, with an average follow-up of 58.9 months (SD± 39.8, Range 22-117). We showed improvement and sustained motion between preoperative and postoperative research visit flexion (p<0.001) and flexion extension-arc (p<0.01). The mean increase in flexion was 98° to 131° and the flexion-extension arc was 36°. Patients were satisfied with the decision to undergo surgery and had sustained ability to complete ADLs.DiscussionThis patient cohort demonstrated a statistically significant increase, as well as long-term maintenance in the flexion and flexion-extension arc. A self-directed, OT/PT-guided, therapy program without CPM was effective. Patients showed good outcomes and were satisfied with their ability to perform ADLs, decreased pain, and the decision to undergo surgery.

An opioid-sparing protocol with intravenous parecoxib can effectively reduce morphine consumption after simultaneous bilateral total knee arthroplasty

Multimodal pain management protocol effectively relieves pain following simultaneous bilateral total knee arthroplasty (SBTKA) but is associated with administration of large amounts of opioids in the perioperative period. In this prospective, randomized, assessor-blinded, single-surgeon clinical trial, the goal was to validate the efficacy of an opioid-sparing protocol for SBTKA with a reduced opioid dose, while achieving similar pain relief with few adverse events. Fifty-six patients who had undergone SBTKA were randomly allocated to receive either an opioid-sparing or opioid-based protocol. The primary outcome parameters were visual analogue scale (VAS) scores at rest, with movement, and cumulative morphine dose, through time. Secondary outcome parameters included drug-related adverse events and range of motion with continuous passive motion device, through time. In the opioid-sparing group, a lower VAS score with movement at postoperative 24 and 72 h was observed compared with the opioid-based group, but the difference did not reach the minimal clinically importance difference. A reduced cumulative morphine dose was noted in the opioid-sparing group at postoperative 24, 48 and 72 h. In conclusion, the opioid-sparing protocol may be used as an alternative modality for pain management following SBTKA. Similar pain relief effects may be achieved utilizing a reduced cumulative opioid dose, with few opioid related adverse events.

Rehabilitation following surgery for flexor tendon injuries of the hand.

Rehabilitation following surgery for flexor tendon injuries of the hand.

Management of Stiffness following Total Knee Arthroplasty: International Survey on Surgeon Preferences.

Introduction: Stiffness following total knee arthroplasty (TKA) is a challenging complication and can result in a poor functional outcome. There is considerable debate concerning the definition, work-up, and optimal management of this complication. The aim of this study was to record the definition of stiffness, management practices, and expectations of outcome among surgeons from an international community using a peer-reviewed questionnaire. Methods: A 23-item peer-reviewed online questionnaire was sent to all members of SICOT to gauge and record the management practices and expectations of outcome in the management of patients with stiffness following TKA. Results: A total of 315 surgeons completed this peer-reviewed questionnaire. Manipulation under anaesthesia (MUA) was the preferred treatment option for stiffness post-TKA, with a majority of the surgeons opting to carry out this procedure between 6 and 12 weeks following the index TKA. Physiotherapy and a continuous passive motion device were also used by the majority of surgeons following MUA, as additional treatment measures. Discussion: MUA is perceived to be a safe and effective primary treatment option for stiffness following TKA. It is best performed between weeks 6 and 12 with expected gains in range of motion from 10 to 20 degrees in 75% of patients.

Introduction of active exercise function by continuous passive motion device for knee joint

Introduction of active exercise function by continuous passive motion device for knee joint

Activity Recommendations After Total Hip and Total Knee Arthroplasty.

A formal unsupervised activity program should be recommended to all patients recovering from total knee arthroplasty (TKA) and total hip arthroplasty (THA). In a subset of all patients undergoing TKA or THA, studies have found that an unsupervised activity program may be as efficacious as supervised physical therapy (PT) after surgery. Certain patients with inadequate independent function may continue to benefit from supervised PT. For TKA, supervised telerehabilitation has also been proven to be an effective modality, with studies suggesting equivalent efficacy compared with supervised in-person PT. Following TKA, there is no benefit to the use of continuous passive motion or cryotherapy devices, but there are promising benefits from the use of pedaling exercises, weight training, and balance and/or sensorimotor training as adjuncts to a multidisciplinary program after TKA. No standardized postoperative limitations exist following TKA, and the return to preoperative activities should be dictated by an individual's competency and should consist of methods to minimize high impact stress on the joint. Despite traditional postoperative protocols recommending range-of-motion restrictions after THA, it is reasonable to recommend that hip precautions may not be needed routinely following elective primary THA.

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

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. 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. 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. 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.

Early Regain of Function and Proprioceptive Improvement Following Knee Arthroplasty.

Techniques that allow early muscle activation, such as closed kinetic chain (CKC) and open kinetic chain (OKC) exercises, may play a beneficial role in the early rehabilitation of the reconstructed knee. However, current rehabilitation regimens have not been shown to reverse post-operative quadriceps activation failure and weakness. To investigate whether patients who use a continuous active motion (CAM) device that follows closed kinetic chain principles have better early post-operative functional improvements than patients who use a continuous passive motion (CPM) device that follows the principles of open kinetic chain principles. A prospective randomized controlled trial with non-blinded study staff. A tertiary care clinic at a teaching hospital. A total of 110 patients signed the consent form and 83 patients participated in the study. Patients were randomly assigned to use either the CPM device for 4 hours daily for 3 weeks (control group), or a CAM device for 3 sessions of 20 minutes for 3 weeks (intervention group), starting 24 hours after knee replacement surgery.The primary outcome measure was to identify the superiority, inferiority, or equivalence of one device at week 4 after knee arthroplasty using various functional outcome measures such as kinesthesia, quadriceps strength, coordination, general orthopaedic outcome measures and narcotic consumption. At 4 weeks, all outcome measurements were comparable between the two groups, with the exception of sit-to-stand test: in the treatment group the time was significantly shorter compared to the control group (P=0.016). Balance was significantly better in both control (P=0.001) and treatment group (P=0.032) compared to prior surgery. Most clinical centers would like to expedite functional recovery of knee arthroplasty patients without increasing the risk of falls. We observed balance and kinesthesia improvements after surgery using either device which may be important to benefit fast recovery programs. Further research is warranted to see whether additional active closed kinetic chain exercised following knee replacement surgery could improve specific functional outcomes such the observed sit-to-stand test. I.

Proprioceptive deficit after total elbow arthroplasty: an observational study

During total elbow arthroplasty (TEA), most of the joint capsule is removed, including many mechanoreceptors important for proprioception, which potentially limits the patient's postoperative functional recovery. We quantified proprioceptive loss by measuring the threshold to detection of passive motion (TTDPM) in patients after unilateral TEA compared with the contralateral side. A continuous passive motion device moving the elbow at 0.5°/s was used to evaluate TTDPM in 8 patients (mean ± standard deviation age, 69.1 ± 9.93 years) at least 1 year after unilateral semiconstricted linked TEA for a range of diagnoses. Elbow function after TEA was assessed using the Mayo Elbow Performance Scale. Postsurgical Mayo scores revealed 4 excellent results, 2 good, and 2 poor. The TTDPM in the elbows undergoing arthroplasty was still significantly higher compared with the contralateral elbow at 4.2° (15.6 ± 6.9 seconds vs. 7.2 ± 2.6 seconds; D = 3.23, P = .01) equivalent to 8.4 seconds. Patients who have had severe joint disease requiring semiconstrained TEA have long-term proprioception deficits. A more conservative technique that maximally preserves insertions and soft tissues, might minimize upper limb proprioceptive deficit.

Rehabilitation following surgery for flexor tendon injuries of the hand

Rehabilitation following surgery for flexor tendon injuries of the hand

The Effect of Passive Movement for Paretic Ankle-Foot and Brain Activity in Post-Stroke Patients

Background: This study aims at investigating the short-term efficacy of the continuous passive motion (CPM) device developed for the therapy of ankle-foot paresis and to investigate by fMRI the blood oxygen level-dependent responses (BOLD) during ankle passive movement (PM). Methods: Sixty-four stroke patients were investigated. Patients were assigned into 2 groups: 49 patients received both 15 min manual and 30 min device therapy (M + D), while the other group (n = 15) received only 15 min manual therapy (M). A third group of stroke patients (n = 12) was investigated by fMRI before and immediately after 30 min CPM device therapy. There was no direct relation between the fMRI group and the other 2 groups. All subjects were assessed using the Modified Ashworth Scale (MAS) and a goniometer. Results: Mean MAS decreased, the ankle's mean plantar flexion and dorsiflexion passive range of motion (PROM) increased and the equinovalgus improved significantly in the M + D group. In the fMRI group, the PM of the paretic ankle increased BOLD responses; this was observed in the contralateral pre- and postcentral gyrus, superior temporal gyrus, central opercular cortex, and in the ipsilateral postcentral gyrus, frontal operculum cortex and cerebellum. Conclusion: Manual therapy with CPM device therapy improved the ankle PROM, equinovalgus and severity of spasticity. The ankle PM increased ipsi- and contralateral cortical activation.