novel Award Second Prize Paper. Functional monitoring during rehabilitation following anterior cruciate ligament reconstruction

Research on an ankle rehabilitation robot for hemiplegic patients after stroke

This paper proposes an ankle rehabilitation robot to assist hemiplegic patients with movement training. The robot consists of two symmetric mechanisms, allowing stroke survivors to execute ankle rehabilitation training based on physiological differences. LPMS-B sensors measure the range of movement (ROM) of the human ankle joint, and the results are used for control parameters of the robot. Control strategies for constant speed training mode, constant torque training mode, and combination training mode are put forth based on the hardware system of the robot. Experiments verify the feasibility of the robot for ankle rehabilitation training. Results show a maximum mean error of 0.3364° between the trajectory of the intact side and the affected side, a maximum mean error of 0.0335°/s between target speed and experimental speed, and a maximum mean error of 0.0775 N m between target torque and experimental torque. The ankle joint rehabilitation robot proposed in this paper can help patients complete the training well under the three control modes.

Pedobarography in Physiotherapy: A Narrative Review on Current Knowledge

Pedobarography is a modern technology enabling the assessment of the locomotor system based on the plantar pressure distribution. The technic is useful in the rehabilitation of various types of dysfunction of body movement. This chapter aims to describe the application of pedobarography in clinical therapy. The qualitative analysis is based on a review of articles in English, French, German, Polish, Portuguese, Spanish, Turkish, and Chinese in Medline/PubMed, Cochrane Library, Embase, and PEDro databases. The search covered the articles on clinical trials, randomized controlled trials, meta-analyses, and reviews published over 1984-2020. The literature shows that pedobarography is a safe non-invasive method that is useful for the examination of foot biomechanics with a reference to the entire musculoskeletal system. A pedobarographic examination enables insight into a motion disorder, its plausible relation to a systemic pathology, and monitoring the course of treatment and rehabilitation.

Lower limb biomechanics before and after anterior cruciate ligament reconstruction: A systematic review

This review aimed to synthesise the findings of literature that have assessed the changes in lower limb biomechanics following anterior cruciate ligament (ACL) reconstructive surgery. Systematic searches of CINHAL, MEDLINE, SCOPUS, and SPORTDiscus databases were run. All included studies had presented biomechanical variables pre- and post-surgery for the same participants. Articles were categorised by the analysed movement, and effect sizes were calculated. Fifty-four studies met the inclusion criteria, providing data on gait (n = 31), balance (n = 12), joint position sense (n = 5), stair ambulation (n = 4), pivoting (n = 6), and landing (n = 5). Measures of balance performance and joint position sense showed improvements from pre- to post-surgery. Changes in joint kinematics were inconsistent between studies, however increased knee flexion excursion, and reduced tibial anterior translation and internal rotation post reconstruction were identified. Joint kinetics reduced in magnitude in the early stages after surgery (≤5 weeks), then increased later in recovery (≥24 weeks). Risk of bias assessment identified most articles had a moderate or high risk (low = 5; moderate = 21; high = 11) resulting from participant retention and surgical intervention differences. The results of the review identified that although lower limb biomechanics did alter following reconstruction, few variables provided consistent results across studies and tasks. The low methodological quality of some articles may have contributed to these inconsistent findings. Alternatively, differences across studies may have resulted from individual coping strategies of participants that have previously been suggested to be present before reconstructive surgery, and future research should look to explore individual coping strategies to ACL reconstruction.

Similarity of Center of Pressure Progression during Walking and Jogging of Anterior Cruciate Ligament Deficient Patients

OBJECTIVE

To evaluate the center of pressure (COP) progression similarity and its change during walking and jogging in Anterior Cruciate Ligament deficient (ACLD) patients.

METHODS

A study was performed in 64 unilateral ACLD subjects and 32 healthy volunteers who walked and jogged on footscan® system at a self-selected speed. COP trajectory during walking and jogging was calculated. The robustness and similarity scores of COP (SSCOP, similarity scores with respect to corresponding COP trajectories) were computed, and then the Analysis of Variance test was employed to compare among different conditions (left or right side, within a subject or between subjects, walking or jogging).

RESULTS

(1) During the same motion status (walking or jogging), SSCOP were higher than 0.885. However, SSCOP between walking and jogging were lower than 0.25 in both the healthy and ACLD group. SSCOP between the intrasubjects were statistically higher than those between the intersubjects (p<0.01). (2) SSCOP in the ACLD group were statistically significantly reduced to 0.885±0.074 compared to 0.912±0.057 in healthy volunteers during walking, and 0.903±0.066 in the ACLD group compared to 0.919±0.050 in the healthy group during jogging (p<0.01).

CONCLUSIONS

SSCOP can distinguish walking from jogging, and SSCOP of ACLD patients would be different from that of healthy controls. The study protocol was approved by the Institutional Research Board of Peking University Third Hospital (IRB00006761-2012010).

Anterior cruciate ligament rupture is associated with abnormal and asymmetrical lower limb loading during walking

OBJECTIVES

Anterior Cruciate Ligament (ACL) deficiency may result in abnormal lower limb loading with increased foot pronation. This study evaluated spatiotemporal parameters and plantar pressure distribution during walking in participants with and without an ACL rupture.

DESIGN

Cross-sectional.

METHODS

Plantar pressure was measured in 42 unilateral ACL deficient (ACLD) participants and 32 healthy controls while walking barefoot. Spatiotemporal parameters, pressure distribution and center of pressure (CoP) during foot roll off were determined. Differences in spatiotemporal parameters and pressure distribution were analyzed using a Linear Mixed Model. CoP position was analyzed with one-way ANOVA.

RESULTS

ACLD participants had a longer contact time and earlier forefoot contact compared to controls. The ACLD side showed a shorter contact time and a faster roll off toward the forefoot compared to the ACL intact side. Compared to controls, ACLD participants had increased pressure under the medioproximal side of the midfoot. Within ACLD participants, the ACLD side had decreased pressure under the heel and increased pressure under the forefoot. Foot pronation was not different between groups or within ACLD participants. CoP of the ACLD participants was significantly more toward the toes during initial contact and toward the heel during foot flat.

CONCLUSIONS

Changes in lower limb loading during barefoot walking in ACLD participants are due to changes in roll off pattern, most likely in order to reduce anterior shear forces on the knee. Dynamic plantar pressure measurements may assist in evaluating and guiding interventions aimed at normalizing lower limb and knee biomechanics in ACL deficiency.

The progression of muscle fatigue during exercise estimation with the aid of high-frequency component parameters derived from ensemble empirical mode decomposition

Muscle fatigue is often monitored via the median frequency derived from the surface electromyography (sEMG) power spectrum during isometric contractions. The power spectrum of sEMG shifting toward lower frequencies can be used to quantify the electromanifestation of muscle fatigue. The dynamic sEMG belongs to a nonstationary signal, which will be affected by the electrode moving, the shift of the muscle, and the change of innervation zone. The goal of this study is to find a more sensitive and stable method in order to sense the progression of muscle fatigue in the local muscle during exercise in healthy people. Five male and five female volunteers participated. Each subject was asked to run on a multifunctional pedaled elliptical trainer for about 30 min, twice a week, and was recorded a total of six times. Three decomposed methods, discrete wavelet transform (DWT), empirical mode decomposition (EMD), and ensemble EMD (EEMD), were used to sense the progression of muscle fatigue. They compared with each other. Although the highest frequency components of sEMG by DWT, EMD, and EEMD have the better performance to sense the progression of muscle fatigue than the raw sEMG, the EEMD has the best performance to reduce nonstationary characteristics and noise of the dynamic sEMG.

Functional Performance Testing After Anterior Cruciate Ligament Reconstruction: A Systematic Review

Background:

When to allow an athlete to return to unrestricted sporting activity after anterior cruciate ligament (ACL) reconstruction remains controversial.

Purpose:

To report the results of functional performance testing reported in the literature for individuals at differing time points following ACL reconstruction and to examine differences between graft types.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review of Medline, Scopus, and Cochrane Central Register of Controlled Trials was performed using PRISMA guidelines. Inclusion criteria were English-language studies that examined any functional rehabilitation test from 6 months to 2 years following ACL reconstruction. All patient-, limb-, and knee-specific demographics were extracted from included investigations. All functional rehabilitation tests were analyzed and compared when applicable.

Results:

The search term returned a total of 890 potential studies, with 88 meeting inclusion and exclusion criteria. A total of 4927 patients were included, of which 66% were male. The mean patient age was 26.5 ± 3.4 years. The predominant graft choices for reconstruction were bone–patellar tendon–bone (BPTB) autograft (59.8%) and hamstring autograft (37.9%). The most commonly reported functional tests were the hop tests. The results of these functional tests, as reported in the Limb Symmetry Index (LSI), improved with increasing time, with nearly all results greater than 90% at 1 year following primary ACL reconstruction. At 6 months postoperatively, a number of isokinetic strength measurements failed to reach 80% LSI, most commonly isokinetic knee extension testing in both BPTB and hamstring autograft groups. The knee flexion strength deficit was significantly less in the BPTB autograft group as compared with those having hamstring autograft at 1 year postoperatively, while no significant differences were found in isokinetic extension strength between the 2 groups.

Conclusion:

Hop testing was the most commonly reported functional test following ACL reconstruction. Increases in performance on functional tests were predictably seen as time increased following surgery. Those with hamstring autografts may experience increased strength deficits with knee flexion versus those having BPTB autograft. These data provide information that may assist providers in determining timing of return to unrestricted sporting activity.

The influence of electromyographic biofeedback therapy on knee extension following anterior cruciate ligament reconstruction: a randomized controlled trial

Background

Loss of knee extension and a deficit in quadriceps strength are frequently found following anterior cruciate ligament (ACL) reconstruction. The aim of this study was to investigate whether the addition of Eletromyographic Biofeedback (EMG BFB) therapy for the vastus medialis muscle to the in the early phase of the standard rehabilitation programme could improve the range of knee extension and strength after ACL reconstruction more than a standard rehabilitation programme. The correlation between EMG measurement and passive knee extension was also investigated.

Method

Sixteen patients, all of whom underwent endoscopic ACL reconstruction using patellar tendon autograft, were randomly assigned to two groups:

• Control group (8 patients): standard rehabilitation protocol; with full weight-bearing postoperative, knee brace (0° extension, 90° flexion), electrical stimulation, aquatics and proprioceptive training.

• The EMG BFB group (8 patients): EMG BFB was added to the standard rehabilitation protocol within the first postoperative week and during each session for the next 6 weeks.

Each patent attended a total of 16 outpatient physiotherapy sessions following surgery. High-Heel-Distance (HHD) Test, range of motion (ROM) and integrated EMG (iEMG) for vastus medialis were measured preoperatively, and at the 1, 2, 4 and 6-week follow ups. Additionally, knee function, swelling and pain were evaluated using standardized scoring scales.

Results

At 6 weeks, passive knee extension (p < 0.002) and the HHD Test were significantly (p < 0.01) better in the EMG BFB group compared to controls. Integrated EMG (vastus medialis) of the EMG BFB group also showed a significant increase after 2 (p < 0.01) and 6 (p < 0.01) weeks. At the 6-week follow up, no significant (p > 0.01) differences were found between the two groups for the assessment of knee function, swelling and pain.

Conclusion

The results indicate that EMG BFB therapy, in the early phase of rehabilitation after ACL reconstruction, is useful in enhancing knee extension. Improved innervation of the vastus medialis can play a key role in the development of postoperative knee extension. EMG BFB therapy is a simple, inexpensive and valuable adjunct to conventional therapeutic modalities.

PARABOLIC FITTING OF ISOTONIC POWER-ANGLE CURVES TO EVALUATE MOTOR DEFICITS IN PATIENTS SUBMITTED TO ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Power-angle curves, describing the isotonic sub-maximal movement of the lower extremities, are better means to evaluate the effects of training protocols and to highlight functional differences between the legs. The aim of this work was to compare the morphology of power-angle curves of pathological subjects (PS) and healthy subjects (HS) and to evaluate the feasibility of this approach to discriminate between pathological and healthy legs. Isotonic evaluation with leg-extension machine was performed on 46 HS and 16 PS previously submitted to knee surgery. The healthy group comprised 33 elderly healthy subjects (EHS) (mean: 65 years) and 13 young healthy subjects (YHS) (mean: 35 years) and the influence of age on the curves was evaluated. All subjects performed a sub-maximal movement with the legs working alone and together. Each curve was interpolated with a parabolic function and the R 2 Pearson coefficient was used as a score for morphological regularity. R 2 of curves of PS obtained with legs working alone were statistically different from those of the HS group, considering both YHS and EHS (p < 0.05). Statistically significant differences between YHS and EHS (p < 0.01) show the importance of age in the modality of performing movements.

Motorized CPM/CAM physiotherapy device with sliding-mode Fuzzy Neural Network control loop

Continuous passive motion (CPM) and controllable active motion (CAM) physiotherapy devices promote rehabilitation of damaged joints. This paper presents a computerized CPM/CAM system that obviates the need for mechanical resistance devices such as springs. The system is controlled by a computer which performs sliding-mode Fuzzy Neural Network (FNN) calculations online. CAM-type resistance force is generated by the active performance of an electric motor which is controlled so as to oppose the motion of the patient's leg. A force sensor under the patient's foot on the device pedal provides data for feedback in a sliding-mode FNN control loop built around the motor. Via an active impedance control feedback system, the controller drives the motor to behave similarly to a damped spring by generating and controlling the amplitude and direction of the pedal force in relation to the patient's leg. Experiments demonstrate the high sensitivity and speed of the device. The PC-based feedback nature of the control loop means that sophisticated auto-adaptable CPM/CAM custom-designed physiotherapy becomes possible. The computer base also allows extensive data recording, data analysis and network-connected remote patient monitoring.

Implementation of CAM physiotherapy device with a virtual spring

Continuous passive motion (CPM) and continuous active motion (CAM) physiotherapy devices are commonly used to promote rehabilitation of damaged synovial joints. A CPM/CAM device with no resistive CAM-type components is presented. In the CPM mode the electric motor functions conventionally, but in the CAM mode, intelligent use of the motor simulates resistive components by driving the motor to exert a force opposing the patient's muscle activity, so as to simulate the effect of a spring load. The system easily connects to the Internet or other data links for automatic monitoring of home patients, hospital networks, research stations, or telemedicine applications.

Digital image correlation: A technique for determining local mechanical conditions within early bone callus

Local mechanical conditions are known to play a role during the regeneration of musculoskeletal tissues, and histomorphometrical investigations of the time course of healing have enabled specific conclusions regarding the mechanosensitivity of tissue differentiation. However, the mechanism for this influence is not clearly understood. In order to extend this analysis, it is essential to link local histological understanding with direct characterisation of the local mechanical environment. Digital image correlation (DIC) is a computer-based image analysis technique that enables the non-contact measurement of strains on material surfaces and is finding application in many areas of biomechanics. Here we report a DIC technique to investigate the local distribution of mechanical strain within regenerating soft tissue sections. We provide exemplary data from analysis of a section of sheep bone callus. An assessment of displacement measurement accuracy gave an RMS error of 4.2 microm, corresponding to an estimated strain error of 1.4%. The sections showed concentrations of up to four times the applied strain and comparison of the strain patterns with histological analysis confirmed that these concentrations reflected boundaries between hard and soft callus.

Die Einlagenversorgung des rheumatischen Fußes

BACKGROUND

Insoles are regarded as an appropriate tool for the management of rheumatic foot disorders. However, a quality control for this purpose has not been established. In our study, the clinical effectiveness of insoles used in patients with rheumatic foot disorders was addressed. In addition, we sought to establish pedobarography as a means of quality control for orthotic management of the rheumatic foot.

MATERIAL AND METHODS

Our study included 20 rheumatoid arthritis patients with painful rheumatic foot deformities who were provided with insoles. Clinical data were obtained by physical examination and a 100-mm pain scale. Pedobarography was performed using the novel pedar cable system with new and individually designed insoles and after a 6-month follow-up. A shoe-only trial served as control. The parameters maximum force, peak pressure, force-time integral, and average pressure were analyzed in anatomical regions and an individually defined overloaded forefoot region.

RESULTS

Clinical improvement was significant after a 6-month follow-up in spite of a heterogeneous group of patients. However, our results could not confirm consistent changes in plantar pressure distribution.

CONCLUSION

As a conclusion, further efforts are necessary to establish a quality control for orthotic management of the rheumatic foot.

Electrical manifestations of muscle fatigue during concentric and eccentric isokinetic knee flexion-extension movements

The quantification of the progression of muscle fatigue during a sustained contraction is a valuable tool in several clinical applications, ranging from the evaluation of functional impairment to the development of specific rehabilitative and training protocols. In these fields, great importance is given to isokinetic contractions. The aim of this paper was twofold: first, to propose signal processing methods for assessing the spectral changes of the surface myoelectric signal due to fatigue during isokinetic concentric and eccentric knee flexion-extension movements at a given angular velocity (60 degrees/s); second, to analyze the electrical manifestations of muscle fatigue of four thigh muscles (vastus lateralis, vastus medialis, rectus femoris, and biceps femoris) in the two contraction modalities (i.e. concentric versus eccentric). We demonstrated that, when considering concentric contractions, localized muscle fatigue can be assessed by computing the mean frequency of the frequency marginal of the time-frequency distribution derived from the surface myoelectric signal collected during each contraction cycle. Stronger nonstationarities were observed in the surface myoelectric data recorded within each cyclical movement of the studied eccentric exercise. Thus we propose the computation of the instantaneous mean frequency of the signal based on an original cross-time-frequency algorithm, which proved more sensitive than the frequency marginal in tracking the spectral changes associated with localized muscle fatigue. We derived the average fatigue pattern of the investigated muscles from experimental data recorded from a sample population consisting of twenty healthy subjects and we statistically compared the two contraction modalities. Our results showed that the electrical manifestations of muscle fatigue during concentric contractions were higher than those found during eccentric contractions, although in the latter modality the torque exerted and the mechanical work produced by the subjects were larger than those recorded during the concentric exercise. The results presented in this paper have potential clinical application and they could play an important future role in investigations of muscle behavior during dynamic, highly fatiguing contractions.

Gait evaluation: a tool to monitor bone healing?

BACKGROUND

Current clinical methods for monitoring fracture healing are often invasive and inaccurate. This paper evaluates the use of a pressure sensitive platform to improve monitoring.

METHODS

Standardised 3 mm diaphyseal bone defects were created in the right tibia of 64 female sheep and stabilised with either a rigid monolateral external fixator or a more flexible variant. Over a nine week healing period gait parameters were measured using a pressure sensitive platform and interfragmentary movements at the fracture site were monitored. Frequency spectra were calculated for the ground reaction forces. The tibiae were tested biomechanically after sacrifice and callus sections were analysed histomorphometrically.

FINDINGS

All animals unloaded the operated and overloaded the contralateral hindlimb. Callus mineralisation and stiffness, as well as limb loading increased during healing whilst interfragmentary movements were reduced. Larger interfragmentary movements resulted in a slower fracture healing rate as documented histologically and biomechanically. Frequency analysis showed upto 14 dB loss of power at frequencies associated with bone mechanotransduction at four weeks postoperatively, reducing to a 3 dB loss at nine weeks.

INTERPRETATION

Gait analysis is a valuable tool for monitoring the course of fracture healing. Different fixation stiffnesses caused different initial interfragmentary movements leading to different healing rates. Ground reaction forces were strongly related to the course of callus mineralisation and thus directly reflected the recovery of stiffness at the fracture site. Reduced levels of loading frequencies that may affect bone healing persist to nine weeks postoperatively.

[Clinical gait analysis]

Clinical gait analysis comprises a well defined repertoire of various methods for valid and reliable assessment. The rapid development of corresponding hardware and software has substantially decreased the efforts necessary for data processing and has promoted the clinical applicability of the procedures. The clinical question defines the amount of methodological input. Clinical gait analysis may provide diagnostic insight into the pathobiomechanics and the pathophysiology of complex gait disorders for which a profound understanding of the underlying causes is a prerequisite for adequate treatment. The methods may help in the screening of gait function following reconstructive surgery as a measure of quality control, the assessment of the severity of a gait disturbance, the evaluation of a rehabilitation process, or the quantification of the effect of orthoses, insoles or specific shoe ware. Simple procedures of gait analysis may suffice to obtain information on gait function which can not be derived by mere clinical observation and which can be incorporated into a clinical concept.

Functional assessment using the step-up-and-over test and forward lunge following ACL reconstruction

This investigation compared lower extremity function of a control group and a group of patients who underwent anterior cruciate ligament (ACL) reconstruction using a repeated measures post-test only control group design. The ACL reconstruction group consisted of 18 patients at least 6 months postoperative (mean 58+/-19 weeks) and the control group consisted of 18 healthy, recreationally active individuals. Both groups performed a step-up-and-over test and a forward lunge on a long force plate. During the step-up-and-over test, the control group produced significantly more force during the initial step than the ACL reconstruction group. Also, when the ACL reconstruction patients led with the involved extremity, they were significantly slower. During the forward lunge test, the impact index and force impulse measurements were significantly greater for the uninvolved leg than the involved leg in the ACL reconstruction group. The implications are that force generation during functional tests may remain compromised for >1 year following reconstruction. The aforementioned tests are promising for evaluation of function following ACL reconstruction.

Gait analysis 6 and 12 months after anterior cruciate ligament reconstruction surgery

Little is known about knee function after anterior cruciate ligament reconstruction in the vital activities of walking and stair use. Gait analysis was done on patients 6 months (n = 8) and 12 months (n = 9) after reconstruction of the anterior cruciate ligament. Paired t tests were used to compare the injured and uninjured knees. During level walking, the patients placed external flexion torques on their injured knees throughout midstance, indicating the absence of quadriceps avoidance gait. The peak external flexion torque (resisted by the knee extensor muscles) placed on the injured knee was significantly less than that of the uninjured knee when ascending stairs (at 12 months, 68.4 and 85.3 N-m in the injured and uninjured knees, respectively) and also when descending stairs (at 12 months, 70.8 and 81.7 N-m in the injured and uninjured knees, respectively). The injured knee produced significantly less power than the uninjured knee when ascending stairs, but this difference was not significant when descending stairs. These findings indicate that asymmetric gait patterns persisted up to 1 year after surgical reconstruction and were more pronounced during stair ascent and descent than in level walking. These results indicate that clinicians should include specific interventions targeted at improving knee function during stair use to restore normal function after anterior cruciate ligament reconstruction.