The reliability of knee joint position testing using electrogoniometry

Retracted Article: Validity and Reliability of Sensor-based Measures of Lower Limb Range of Motion in Soccer Players: a Cross-sectional Study

Ein Defizit der Beweglichkeit gilt als Risikofaktor für Verletzungen der unteren Extremität im Fußball. Zur Messung des Bewegungsausmaßes (Range of Motion [ROM]) eines Gelenks werden analoge Goniometer verwendet. Zunehmend entwickelte sensorbasierte Verfahren wurden hinsichtlich ihrer Testgüte noch nicht hinreichend untersucht. Ziel dieser Studie war die Bestimmung der Übereinstimmungsvalidität sowie der Intratester- und Intertester-Reliabilität sensorbasierter Messungen des Bewegungsumfangs der unteren Extremität bei Fußballspielern. 36 beschwerdefreie Amateurfußballer (Alter: 26,3 ± 4,7 Jahre) wurden in die Studie eingeschlossen. Aus 5 Physiotherapeuten wurden 3 zufällig bestimmt, um die Messungen durchzuführen. Zwei Tester führten die Messungen (1. ROM Knie aus Langsitz; 2. Streckdefizit Knie aus Langsitz; 3. ROM Knie aus Stand; 4. ROM Sprunggelenk Dorsalextension [DE] während Ausfallschritt; 5. ROM Sprunggelenk Plantarflexion [PF] aus Sitz auf dem Stuhl) mit dem digitalen Sensor durch (Index-Test). Der 3. Tester übernahm die Messungen mit dem analogen Goniometer nach Neutral-Null-Methode mit den Probanden in Rückenlage (Referenzstandard). Zur statistischen Analyse wurden der Pearson-Korrelationskoeffizient r, Bland-Altman-Analysen (BAA) und der Intraklassenkorrelationskoeffizient (ICC) verwendet (p ≤ 0,05). Nur bei den Messungen 4 und 5 zeigten sich in der BAA akzeptable mittlere Differenzen von 8,4° (DE) und −10,2° (PF). Bei Messung 1 lag eine moderate Korrelation (r = 0,582) vor. Die sensorbasierten Messungen des Bewegungsumfangs des Knie- und Sprunggelenks wiesen eine exzellente Intra- und Intertesterreliabilität auf (ICC = 0,949–0,986; ICC = 0,895–0,968). Mit dem hier verwendeten etablierten Referenzstandard zeigten sie jedoch nur eine eingeschränkte Übereinstimmung, was mit den unterschiedlichen Ausgangspositionen von Index-Test und Referenzstandard erklärt werden kann.

A portable system to measure knee extensor spasticity after spinal cord injury

BACKGROUND

The pendulum test is a quantitative method used to assess knee extensor spasticity in humans with spinal cord injury (SCI). Yet, the clinical implementation of this method remains limited. The goal of our study was to develop an objective and portable system to assess knee extensor spasticity during the pendulum test using inertial measurement units (IMU).

METHODS

Spasticity was quantified by measuring the first swing angle (FSA) using a 3-dimensional optical tracking system (with external markers over the iliotibial band, lateral knee epicondyle, and lateral malleolus) and two wireless IMUs (positioned over the iliotibial band and mid-part of the lower leg) as well as a clinical exam (Modified Ashworth Scale, MAS).

RESULTS

Measurements were taken on separate days to assess test-retest reliability and device agreement in humans with and without SCI. We found no differences between FSA values obtained with the optical tracking system and the IMU-based system in control subjects and individuals with SCI. FSA values from the IMU-based system showed excellent agreement with the optical tracking system in individuals with SCI (ICC > 0.98) and good agreement in controls (ICC > 0.82), excellent test-retest reliability across days in SCI (ICC = 0.93) and good in controls (ICC = 0.87). Notably, FSA values measured by both systems showed a strong association with MAS scores ( ρ  ~ -0.8) being decreased in individuals with SCI with higher MAS scores, reflecting the presence of spasticity.

CONCLUSIONS

These findings suggest that our new portable IMU-based system provides a robust and flexible alternative to a camera-based optical tracking system to quantify knee extensor spasticity following SCI.

Validation of a novel clinical tool for monitoring distal limb stiffness

Objective

To validate a novel technique to measure limb stiffness in a clinical setting.

Animals

Three horses and three ponies owned by the Royal Veterinary College.

Procedures

Limb stiffness indices for both forelimbs were first derived using the gold standard of kinematic analysis. Using the same animals, limb stiffness indices were then calculated using portable floor scales to record weight and an electrogoniometer to record changes in metacarpophalangeal joint angle. The two techniques were then assessed for correlation and repeatability.

Results

The repeatability of limb stiffness measurement using the novel clinical tool was considered to be good based on a small coefficient of variation (5.70%). The correlation of limb stiffness as derived by both methods was high (r = 0.78, p < 0.01). Limb stiffness was positively correlated with the mass of the subject (r = 0.85, p < 0.01), with heavier horses having greater limb stiffness.

Clinical relevance

This study has compared a novel method to measure distal forelimb stiffness non-invasively in a clinical setting to kinematic analysis in six equids. It has demonstrated that limb stiffness increases in a linear fashion with body mass consistent with the role of forelimbs providing energy storage. Because in vivo limb stiffness has been shown previously to alter with injury to the superficial digital flexor tendon, it is hypothesized that this technique will offer a practical technique for the clinician to assess limb stiffness in clinical cases. Further study will be necessary to determine its clinical usefulness in such cases.

Reliability of the active knee joint position sense test and influence of limb dominance and sex

The output of a sensorimotor performance can be measured with the joint position sense (JPS) test. However, investigations of leg dominance, sex and quality measures on this test are limited. Therefore, these potential influencing factors as well as reliability and consistency measures were evaluated for angular reproduction performance and neuromuscular activity during the active knee JPS test in healthy participants. Twenty healthy participants (10 males; 10 females; age 29 ± 8 years; height 165 ± 39 cm; body mass 69 ± 13 kg) performed a seated knee JPS test with a target angle of 50°. Measurements were conducted in two sessions separated by two weeks and consisted of two blocks of continuous angular reproduction (three minutes each block). The difference between reproduced and target angle was identified as angular error measured by an electrogoniometer. During reproduction, the neuromuscular activity of the quadriceps muscle was assessed by surface electromyography. Neuromuscular activity was normalized to submaximal voluntary contraction (subMVC) and displayed per muscle and movement phase. Differences between leg dominance and sex were calculated using Friedman-test (α = 0.05). Reliability measures including intraclass correlation coefficient (ICC), Bland-Altman analysis (bias ± limits of agreement (LoA)) and minimal detectable change (MDC) were analysed. No significant differences between leg dominance and sex were found in angular error and neuromuscular activity. Angular error demonstrated inter-session ICC scores of 0.424 with a bias of 2.4° (± 2.4° LoA) as well as MDC of 6.8° and moderate intra-session ICC (0.723) with a bias of 1.4° (± 1.65° LoA) as well as MDC of 4.7°. Neuromuscular activity for all muscles and movement phases illustrated inter-session ICC ranging from 0.432 to 0.809 with biases between - 2.5 and 13.6% subMVC and MDC from 13.4 to 63.9% subMVC. Intra-session ICC ranged from 0.705 to 0.987 with biases of - 7.7 to 2.4% subMVC and MDC of 2.7 to 46.5% subMVC. Leg dominance and sex seem not to influence angular reproduction performance and neuromuscular activity. Poor to excellent relative reliability paired with an acceptable consistency confirm findings of previous studies. Comparisons to pathological populations should be conducted with caution.

Test-Retest Reliability of a New Device Versus a Long-Arm Goniometer to Evaluate Knee Proprioception

CONTEXT

Many methods used to evaluate knee proprioception have shortcomings that limit their use in clinical settings. Based on an inexpensive 3D camera, a new portable device was recently used to evaluate the joint position sense (JPS) of the knee joint. However, the test-retest reliability of the new method remains unclear. This study aimed to evaluate the test-retest reliability of the new device and a long-arm goniometer for assessing knee JPS, and to compare the variability of the 2 methods.

DESIGN

Prospective observational study of the test-retest reliability of knee JPS measurements.

METHODS

Twenty-one healthy adults were tested in 2 sessions with a 1-week interval. Three target knee flexion angles (30°, 45°, and 60°) were reproduced in each session. Target and reproduced angles were measured with both methods. Intraclass correlation coefficients, standard error of the measurement, and Bland-Altman plots were used to quantify test-retest reliability. Paired t tests were used to compare knee JPS (absolute error of the target-reproduced angle) between the methods.

RESULTS

The new device (good to excellent intraclass correlation coefficients .74-.80; standard error of the measurement 0.52°-0.61°) demonstrated better test-retest reliability than the goniometer (poor to fair intraclass correlation coefficients .23-.43; standard error of the measurement 0.89°-2.07°) and better test-retest agreement (respective mean differences for the 30°, 45°, and 60° knee angles: 0.11°, 0.13°, and 0.41° for the new system; 0.84°, 1.52°, and 1.18° for the goniometer). The measurements (absolute errors of the target-reproduced angles) with the goniometer were significantly greater than those with the new device (P < .05); the SDs of repeated measurements with the goniometer (1.50°-2.41°) were greater than with the new device (1.08°-1.38°).

CONCLUSIONS

Given that the new device has good reliability and sufficient precision, it is the better alternative for evaluating knee JPS. Goniometers should be used with caution to assess knee JPS.

Effects of Task-Specific Training after Cognitive Sensorimotor Exercise on Proprioception, Spasticity, and Gait Speed in Stroke Patients: A Randomized Controlled Study

Background and objectives: Common problems in stroke patients include loss of proprioception, spasticity, and impaired gait. The purpose of this study was to examine the effects of task-specific training (TST) combined with cognitive sensorimotor exercise (CSE) on proprioception, spasticity and gait speed in stroke patients. Materials andMethods: Thirty-seven subjects were randomly divided into three groups; (1) the TST after CSE group (Experimental I, n = 13); (2) the TST group (Experimental II, n = 12), and (3) a conventional physical therapy training group (control group, n = 12). Evaluations were performed before the commencement of training and again eight weeks after training was initiated. An electrogoniometer was used to evaluate proprioception variation. The composite spasticity score (CSS) and MyotonePRO were used to evaluate spasticity. In addition, 10 m walk test was used to assess gait speed. Results: After training, the Experimental I group showed significant improvement in proprioception compared to the Experimental II and control group (p < 0.05). In CSS, gastrocnemius muscle tone (GMT) and gait speed among three groups, Experimental I group differed significantly after eight weeks of training compared to the control group (p < 0.05). Conclusions: These findings suggest that the TST combined with CSE provided significant improvements in proprioception, spasticity, and gait speed.

Contractile behavior of the gastrocnemius medialis muscle during running in simulated hypogravity

Vigorous exercise countermeasures in microgravity can largely attenuate muscular degeneration, albeit the extent of applied loading is key for the extent of muscle wasting. Running on the International Space Station is usually performed with maximum loads of 70% body weight (0.7 g). However, it has not been investigated how the reduced musculoskeletal loading affects muscle and series elastic element dynamics, and thereby force and power generation. Therefore, this study examined the effects of running on the vertical treadmill facility, a ground-based analog, at simulated 0.7 g on gastrocnemius medialis contractile behavior. The results reveal that fascicle-series elastic element behavior differs between simulated hypogravity and 1 g running. Whilst shorter peak series elastic element lengths at simulated 0.7 g appear to be the result of lower muscular and gravitational forces acting on it, increased fascicle lengths and decreased velocities could not be anticipated, but may inform the development of optimized running training in hypogravity. However, whether the alterations in contractile behavior precipitate musculoskeletal degeneration warrants further study.

Effects of variable frequencies of kinesthesia, balance and agility exercise program in adults with knee osteoarthritis: study protocol for a randomized controlled trial

Background

Knee osteoarthritis (OA) is a common painful and disabling condition that affects older individuals. Proprioceptive training programs in the form of kinesthesia, balance and agility (KBA) exercises have been reported to be beneficial for individuals with knee OA. However, the most optimal training dosage of KBA exercises is still unclear. The aim of this study is to determine the effects of different frequencies of KBA training (i.e., twice-weekly or thrice-weekly) in adults with knee OA.

Methods

A single (assessor) blind, three-arm parallel, multi-center randomized controlled trial will be conducted. One hundred twenty adults with knee OA will be recruited from four tertiary hospitals in Northwestern Nigeria and randomly assigned into one of three intervention groups; twice-weekly KBA (n = 40), thrice-weekly KBA (n = 40), and conventional physiotherapy (n = 40) in the ratio of 1:1:1. Participants in the conventional physiotherapy group will receive two sessions of brief patient education, and sixteen sessions of ultrasound therapy, and stretching and strengthening exercises for 8 weeks. Participants in the two different KBA groups will receive KBA training according to the designed sessions for 8 weeks in addition to the conventional physiotherapy program. All groups will be assessed pre-intervention, immediately post-intervention and at 3 months, 4 months, and 6 months post-randomization. The primary outcome will be physical function (Ibadan Knee and Hip Osteoarthritis Outcome Measure) whereas the secondary outcomes will be pain intensity (Visual Analogue Scale for pain), knee stability (Knee Outcome Survey-Activities of Daily Living Scale), proprioception (electronic goniometer), and quality of life (Osteoarthritis Knee and Hip Quality of Life Questionnaire).

Discussion

The findings of this study may provide evidence on the effectiveness of KBA exercise training and the ideal number of sessions needed to achieve the highest effectiveness in adults with knee OA.

Trial registration

Pan African Clinical Trials Registry (PACTR201810713260138). Registered on 28 November 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05386-3.

Effects of a Targeted Exercise Program on Inter-Leg Asymmetries in Patients with Patellofemoral Pain

Patellofemoral pain (PFP) is often associated with impaired muscle strength, flexibility, and stability. It has been suggested that inter-leg asymmetries have an important role in increasing the risk of musculoskeletal injuries, including PFP. Thus, the aim of this study was to identify significant asymmetries and determine the effects of a symmetry targeted exercise program in patients with PFP. Eighteen patients aged 13 to 54 years (24.17 ± 12.52 years) with PFP participated in this study. Strength, flexibility and stability outcomes of the trunk, hip, knee and ankle muscles were assessed. A single-group pretest–posttest design was used to assess changes in inter-leg and agonist–antagonist asymmetries resulting from the 8-week period of the supervised exercise program. Results indicated a significant improvement in inter-leg symmetry regarding bilateral stance in a semi-squat position (p = 0.020, d = 0.61, df = 17) and ankle plantarflexion (p = 0.003, d = 0.32, df = 17) and ankle dorsiflexion strength (p < 0.001, d = 0.46, df = 17). In addition, the ratio of ankle dorsiflexion/plantarflexion (p = 0.036, d = 1.14, df = 17) and hip extension/flexion (p = 0.031, d = 0.94, df = 16) changed significantly during the intervention period. To our knowledge, this was the first study to evaluate inter-leg asymmetries resulting from a period of a supervised exercise program. The results indicate that an exercise program focusing on individual asymmetries may influence specific deficits and contribute to better rehabilitation outcomes.

Humanoid Robot Based Platform to Evaluate the Efficacy of Using Inertial Sensors for Spasticity Assessment in Cerebral Palsy

Spasticity is commonly present in individuals with cerebral palsy (CP) and manifests itself as shaky movements, muscle tightness and joint stiffness. Accurate and objective measurement of spasticity is investigated using inertial measurement unit (IMU) sensors. However, use of current IMU-based devices is limited to clinics in urban areas where experienced and trained health professionals are available to collect spasticity data. Designing these devices based on the wearable internet of things based architectures with edge computing will expand their use to home, aged care or remote clinics enabling less-experienced health professionals or care givers to collect spasticity data. However, these new designs require rigorous testing during their prototyping stage and collection of supporting data for regulatory approvals. This work demonstrates that a humanoid robot can act as an accurate model of the movements of CP individuals performing pendulum test during their spasticity assessment. Utilizing this model, we present a robust platform to evaluate new designs of IMU-based spasticity measurement devices.

Effect of Turmacin supplementation on joint discomfort and functional outcome among healthy participants - A randomized placebo-controlled trial

OBJECTIVE

Curcuma longa has been widely used in Ayurveda for its medicinal properties and Turmacin was developed from C. longa as a standardized extract containing turmerosaccharides. In this clinical trial, the effect of Turmacin on knee joint discomfort in healthy adults subjected to strenuous physical activity was evaluated.

DESIGN

Double-blind, triple-arm, parallel-group, randomized placebo-controlled trial.

SETTING

Healthy participants from an urban tertiary care teaching hospital.

INTERVENTION

Healthy participants were randomized in 1:1:1 ratio to receive either Turmacin 0.5 g/1 g or placebo once daily for 84 days. The participants were subjected to 10-minute strenuous exercise.

OUTCOME MEASURES

Time to initial pain, final pain score on a visual analogue scale, range of movement (ROM) of knee and the force of contractions of muscles around the knee joint.

RESULTS

A total of n = 90 participants were recruited. The mean final pain scores were significantly lower in the Turmacin 1 g and Turmacin 0.5 g when compared with the placebo from day-7 and day-5 onwards respectively. The survival analysis consistently showed a decreased hazard for early onset of pain in both the Turmacin groups. On day-84, the difference in mean ROM between Turmacin 0.5 g and placebo was 4.79 degrees (p = 0.008) and that for Turmacin 1 g and placebo was 2.34 degrees (p = 0.306). The difference in muscle force for isokinetic contractions of the quadriceps at angular velocities of 120 and 180 was significant between Turmacin 0.5 g and placebo (p = 0.002 and p = 0.005 respectively) while that for Turmacin 1 g & Turmacin 0.5 g (p = 0.206 and p = 0.414 respectively) and Turmacin 1 g & Placebo (p = 0.046 and p = 0.037) were not significant. However, in the within group analysis participants in Turmacin 1 g group had better preserved muscle functions than Turmacin 0.5 g group at angular velocities of 120 and 180 when compared with placebo.

CONCLUSION

Turmacin (0.5 g and 1 g) was efficacious when compared to placebo in increasing the pain threshold and knee ROM in healthy participants with minor adverse events.

The Efficacy of Simultaneously Training 2 Motion Targets During a Squat Using Auditory Feedback

Auditory feedback is a simple, low-cost training solution that can be used in rehabilitation, motor learning, and performance development. The use has been limited to the instruction of a single kinematic or kinetic target. The goal of this study was to determine if auditory feedback could be used to simultaneously train 2 lower-extremity parameters to perform a bodyweight back squat. A total of 42 healthy, young, recreationally active males participated in a 4-week training program to improve squat biomechanics. The Trained group (n = 22) received 4 weeks of auditory feedback. Feedback focused on knee flexion angle and center of pressure under the foot at maximum squat depth. The Control group (n = 20) performed squats without feedback. Subjects were tested pre, post, and 1 week after training. The Trained group achieved average target knee flexion angle within 1.73 (1.31) deg (P < .001) after training and 5.36 (3.29) deg (P < .01) at retention. While achieving target knee flexion angle, the Trained group maintained target center of pressure (P < .001). The Control group improved knee range of motion, but were not able to achieve both parameter targets at maximum squat depth (P < .90). Results from this study demonstrate that auditory feedback is an effective way to train 2 independent biomechanical targets simultaneously.

Quantitative Modeling of Spasticity for Clinical Assessment, Treatment and Rehabilitation

Spasticity, a common symptom in patients with upper motor neuron lesions, reduces the ability of a person to freely move their limbs by generating unwanted reflexes. Spasticity can interfere with rehabilitation programs and cause pain, muscle atrophy and musculoskeletal deformities. Despite its prevalence, it is not commonly understood. Widely used clinical scores are neither accurate nor reliable for spasticity assessment and follow up of treatments. Advancement of wearable sensors, signal processing and robotic platforms have enabled new developments and modeling approaches to better quantify spasticity. In this paper, we review quantitative modeling techniques that have been used for evaluating spasticity. These models generate objective measures to assess spasticity and use different approaches, such as purely mechanical modeling, musculoskeletal and neurological modeling, and threshold control-based modeling. We compare their advantages and limitations and discuss the recommendations for future studies. Finally, we discuss the focus on treatment and rehabilitation and the need for further investigation in those directions.

Can texture change joint position sense at the knee joint in those with poor joint position accuracy?

Purpose: Skin contributes to joint position sense (JPS) at multiple joints. Altered cutaneous input at the foot can modulate gait and balance and kinesiology tape can enhance proprioception at the knee, but its effect may be dependent on existing capacity. The effect of texture at the knee, particularly in those with poor proprioception, is unknown. The aim of this study was to determine the effect of textured panels on JPS about the knee. Materials and methods: Eighteen healthy females were seated in an adjustable chair. Their left leg (target limb) moved passively from 65° to a target of flexion (115° or 90°) or extension (40°). Their right leg (matching limb) was passively moved towards this target angle and participants indicated when their limbs felt aligned. We tested three textured panels over the knee of the matching limb and two control conditions. The target limb maintained a control panel. Directional error, absolute error and variable error in matching between limbs were calculated. Results: On average textured panels over the knee increased JPS error compared to control pants for participants with poor JPS. These participants undershot the target at 90° of flexion significantly more with textured panels (-11° ± 3°) versus control (-7° ± 3°, p = 0.04). Conclusions: For participants with poor JPS accuracy, increased JPS error at 90° with a textured panel suggests these individuals utilised altered cutaneous information to adjust joint position. We propose increased error results from enhanced skin input at the knee leading to the perception of increased flexion.

From Emotions to Mood Disorders: A Survey on Gait Analysis Methodology

Mood disorders affect more than 300 million people worldwide and can cause devastating consequences. Elderly people and patients with neurological conditions are particularly susceptible to depression. Gait and body movements can be affected by mood disorders, and thus they can be used as a surrogate sign, as well as an objective index for pervasive monitoring of emotion and mood disorders in daily life. Here we review evidence that demonstrates the relationship between gait, emotions and mood disorders, highlighting the potential of a multimodal approach that couples gait data with physiological signals and home-based monitoring for early detection and management of mood disorders. This could enhance self-awareness, enable the development of objective biomarkers that identify high risk subjects and promote subject-specific treatment.

Reliability and validity of clinically accessible smartphone applications to measure joint range of motion: A systematic review

Measuring joint range of motion is an important skill for many allied health professionals. While the Universal Goniometer is the most commonly utilised clinical tool for measuring joint range of motion, the evolution of smartphone technology and applications (apps) provides the clinician with more measurement options. However, the reliability and validity of these smartphones and apps is still somewhat uncertain. The aim of this study was to systematically review the literature regarding the intra- and inter-rater reliability and validity of smartphones and apps to measure joint range of motion. Eligible studies were published in English peer-reviewed journals with full text available, involving the assessment of reliability and/or validity of a non-videographic smartphone app to measure joint range of motion in participants >18 years old. An electronic search using PubMed, Medline via Ovid, EMBASE, CINAHL, and SPORTSDiscus was performed. The risk of bias was assessed using a standardised appraisal tool. Twenty-three of the eligible 25 studies exceeded the minimum 60% score to be classified as a low risk of bias, although 3 of the 13 criteria were not achieved in >50% of the studies. Most of the studies demonstrated adequate intra-rater or inter-rater reliability and/or validity for >50% of the range of motion tests across all joints assessed. However, this level of evidence appeared weaker for absolute (e.g. mean difference ± limit of agreement, minimal detectable change) than relative (e.g. intraclass correlation, correlation) measures; and for spinal rotation than spinal extension, flexion and lateral flexion. Our results provide clinicians with sufficient evidence to support the use of smartphones and apps in place of goniometers to measure joint motion. Future research should address some methodological limitations of the literature, especially including the inclusion of absolute and not just relative reliability and validity statistics.

A lightweight sensing platform for monitoring sleep quality and posture: a simulated validation study

Background

The prevalence of self-reported shoulder pain in the UK has been estimated at 16%. This has been linked with significant sleep disturbance. It is possible that this relationship is bidirectional, with both symptoms capable of causing the other. Within the field of sleep monitoring, there is a requirement for a mobile and unobtrusive device capable of monitoring sleep posture and quality. This study investigates the feasibility of a wearable sleep system (WSS) in accurately detecting sleeping posture and physical activity.

Methods

Sixteen healthy subjects were recruited and fitted with three wearable inertial sensors on the trunk and forearms. Ten participants were entered into a ‘Posture’ protocol; assuming a series of common sleeping postures in a simulated bedroom. Five participants completed an ‘Activity’ protocol, in which a triphasic simulated sleep was performed including awake, sleep and REM phases. A combined sleep posture and activity protocol was then conducted as a ‘Proof of Concept’ model. Data were used to train a posture detection algorithm, and added to activity to predict sleep phase. Classification accuracy of the WSS was measured during the simulations.

Results

The WSS was found to have an overall accuracy of 99.5% in detection of four major postures, and 92.5% in the detection of eight minor postures. Prediction of sleep phase using activity measurements was accurate in 97.3% of the simulations. The ability of the system to accurately detect both posture and activity enabled the design of a conceptual layout for a user-friendly tablet application.

Conclusions

The study presents a pervasive wearable sensor platform, which can accurately detect both sleeping posture and activity in non-specialised environments. The extent and accuracy of sleep metrics available advances the current state-of-the-art technology. This has potential diagnostic implications in musculoskeletal pathology and with the addition of alerts may provide therapeutic value in a range of areas including the prevention of pressure sores.

Electronic supplementary material

The online version of this article (10.1186/s40001-018-0326-9) contains supplementary material, which is available to authorized users.

Smartphone-based accelerometry is a valid tool for measuring dynamic changes in knee extension range of motion

INTRODUCTION

Measurement of static joint range of motion is used extensively in orthopaedic and rehabilitative communities to benchmark treatment efficacy. Static measures are, however, insufficient in providing detailed information about patient impairments. Dynamic range of motion measures could provide more detailed information about patient impairments thus leading to better clinical assessments. Reliable and valid methods are available, but due to limitations in the present technology, dynamic measures are seldom performed in clinical settings. The objective of this study was to determine the validity of smartphone-based accelerometry measuring the dynamic range of motion of the knee joint during a passively executed extension movement.

MATERIALS AND METHODS

Dynamic knee extension range of motion was examined three consecutive times in twenty-one healthy male subjects utilising an isokinetic dynamometer to generate passively the extension motion. Measurements of joint angles in dynamic knee extension were performed using two methods: (i) isokinetic dynamometer (gold-standard method, Biodex System 4 Pro) and (ii) smartphone (iPhone 6, attached to the tibia) accelerometry data.

RESULTS

Tests of validity showed excellent correlation (rs=0.899) between methods, with a low standard error of measurement of 0.62deg. and limits of agreement ranging from -9.1 to 8.8deg. Interclass correlation coefficients showed excellent between-measures reliability (ICC>0.862) for both methods.

CONCLUSIONS

Smartphone-based accelerometry is a valid tool for measuring the range of motion at the knee joint during dynamic extension movements. This method enables the clinician to carry out simple, low cost, and valid clinical measurements of dynamic knee extension range of motion.

Estimation of joint position error

Joint position error (JPE) is frequently used to assess proprioception in rehabilitation and sport science. During position-reposition tests the subject is asked to replicate a specific target angle (e.g. 30° of knee flexion) for a specific number of times. The aim of this study is to find an effective method to estimate JPE from the joint kinematic signal. Forty healthy subjects were tested to assess knee joint position sense. Three different methods of JPE estimation are described and compared using a hierarchical clustering approach. Overall, the 3 methods showed a high degree of similarity, ranging from 88% to 100%. We concluded that it is preferable to use the more user-independent method, in which the operator does not have to manually place "critical" markers.

Electrogoniometer measurement and directional analysis of wrist angles and movements during the Sollerman hand function test

STUDY DESIGN

Clinical measurement.

INTRODUCTION

To investigate the characteristics of wrist motion (area, axis, and location) during activities of daily living (ADL) using electrogoniometry.

METHODS

A sample of 83 normal volunteers performed the Sollerman hand function test (SHFT) with a flexible biaxial electrogoniometer applied to their wrists. This technique is accurate and reliable and has been used before for assessment of wrist circumduction in normal volunteers. A software package was used to overlay an ellipse of best fit around the 2-dimensional trace of the electrogoniometer mathematically computing the area, location, and axis angle of the ellipse.

RESULTS

Most ADL could be completed within 20% of the total area of circumduction (3686°° ± 1575°°) of a normal wrist. An oblique plane in radial extension and ulnar flexion (dart-throwing motion plane) was used for rotation (-14° ± 32°) and power grip tasks (-29° ± 25°) during ADL; however, precision tasks (4° ± 28°), like writing, were performed more often in the flexion extension plane. In the dominant hand, only 2 power tasks were located in flexion region (cutting play dough [ulnar] and pouring carton [radial]), precision tasks were located centrally, and rotation and other power tasks were located in extension region.

DISCUSSION

This study has identified that wrist motion during the ADL requires varying degrees of movement in oblique planes. Using electrogoniometry, we could visualize the area, location, and plane of motion during ADL. This could assist future researchers to compare procedures leading to loss of motion in specific quadrants of wrist motion and its impact on patient's ability in performing particular ADL. It could guide hand therapists to specifically focus on retraining the ADL that may be affected when wrist range of motion is lost after injury.

LEVEL OF EVIDENCE

Diagnostic level III.

MOVEMENT MEASUREMENT VALIDITY AND RELIABILITY OF THE IMAGE J PROGRAM FOR KINEMATIC ANALYSIS

Background: While advanced motion analysis systems can provide accurate kinematic information, the majorities of motion analysis systems are stationary, expensive and time consuming. Image J is a Java-based image processing program that was originally developed at the National Institutes of Health and has rapidly gained widespread acceptance among rehabilitation specialists as a portable and affordable alternative motion analysis system. However, the validity and reliability of the Image J program have not been well established. Objective: The purpose of this study was to investigate the validity and test–retest reliability of the Image J kinematic analysis system. The Image J kinematic analysis system is designed to produce precise kinematic evidence during normal and pathological static and dynamic movement patterns. Methods: The Image J motion analysis system was concurrently compared with the electrogoniometer system as a reference standard measure by obtaining sagittal kinematic knee joint angle data. Results: Image J motion analysis system measurement revealed outstanding validity ([Formula: see text] and [Formula: see text]). The test–retest reliability for kinematic knee angle data showed remarkable consistency (Cronbach’s [Formula: see text]). Conclusions: This study provides the first evidence highlighting the Image J kinematic analysis system’s excellent validity and reliability for evaluating human kinematic movements in elderly people with hemiparetic stroke.

The effect of proficiency level on measurement error of range of motion

[Purpose] The aims of this study were to evaluate the type and extent of error in the measurement of range of motion and to evaluate the effect of evaluators’ proficiency level on measurement error. [Subjects and Methods] The participants were 45 university students, in different years of their physical therapy education, and 21 physical therapists, with up to three years of clinical experience in a general hospital. Range of motion of right knee flexion was measured using a universal goniometer. An electrogoniometer attached to the right knee and hidden from the view of the participants was used as the criterion to evaluate error in measurement using the universal goniometer. The type and magnitude of error were evaluated using the Bland-Altman method. [Results] Measurements with the universal goniometer were not influenced by systematic bias. The extent of random error in measurement decreased as the level of proficiency and clinical experience increased. [Conclusion] Measurements of range of motion obtained using a universal goniometer are influenced by random errors, with the extent of error being a factor of proficiency. Therefore, increasing the amount of practice would be an effective strategy for improving the accuracy of range of motion measurements.

Effect of Body-Weight-Support Running on Lower-Limb Biomechanics

Study Design Controlled laboratory study. Background Body-weight-support (BWS) running is increasing in popularity, despite limited evidence of its effects on running mechanics. Objectives To determine the effect of increasing BWS on lower-limb biomechanics during lower-body positive-pressure (LBPP) treadmill running. Methods Fourteen male recreational runners completed 15 randomized trials on an LBPP treadmill at 5 levels of BWS and 3 velocities (1-minute trials with 3-minute recovery). Knee and ankle kinematic data were recorded continuously via electrogoniometry. Synchronous in-shoe plantar-pressure data identified stride onset and quantified foot-segment forces. Data were recorded during the final 30 seconds of each trial and averaged over 10 consecutive stride cycles. Results Higher levels of BWS resulted in significantly (P<.001) increased stride duration, reduced stride frequency, and reduced ground contact time (GCT). In addition, normalized GCT (GCT/stride duration) was significantly reduced (P<.001), indicating increased flight time. Increasing BWS resulted in significant reductions (P<.001) in peak knee flexion and dorsiflexion and reduced overall knee and ankle range of motion during the stance phase. Conclusion Running on an LBPP treadmill alters lower-limb kinematics, resulting in reduced ankle and knee joint range of motion. In addition, increased BWS alters stride characteristics, resulting in shorter GCT and longer flight time. Clinicians must be aware of lower-limb kinematic alterations to provide safe and effective parameters for rehabilitation involving LBPP treadmills. J Orthop Sports Phys Ther 2016;46(9):784-793. doi:10.2519/jospt.2016.6503.

Robot-aided assessment of lower extremity functions: a review

The assessment of sensorimotor functions is extremely important to understand the health status of a patient and its change over time. Assessments are necessary to plan and adjust the therapy in order to maximize the chances of individual recovery. Nowadays, however, assessments are seldom used in clinical practice due to administrative constraints or to inadequate validity, reliability and responsiveness. In clinical trials, more sensitive and reliable measurement scales could unmask changes in physiological variables that would not be visible with existing clinical scores.In the last decades robotic devices have become available for neurorehabilitation training in clinical centers. Besides training, robotic devices can overcome some of the limitations in traditional clinical assessments by providing more objective, sensitive, reliable and time-efficient measurements. However, it is necessary to understand the clinical needs to be able to develop novel robot-aided assessment methods that can be integrated in clinical practice.This paper aims at providing researchers and developers in the field of robotic neurorehabilitation with a comprehensive review of assessment methods for the lower extremities. Among the ICF domains, we included those related to lower extremities sensorimotor functions and walking; for each chapter we present and discuss existing assessments used in routine clinical practice and contrast those to state-of-the-art instrumented and robot-aided technologies. Based on the shortcomings of current assessments, on the identified clinical needs and on the opportunities offered by robotic devices, we propose future directions for research in rehabilitation robotics. The review and recommendations provided in this paper aim to guide the design of the next generation of robot-aided functional assessments, their validation and their translation to clinical practice.

Effectiveness of adaptive silverware on range of motion of the hand

Background. Hand function is essential to a person’s self-efficacy and greatly affects quality of life. Adapted utensils with handles of increased diameters have historically been used to assist individuals with arthritis or other hand disabilities for feeding, and other related activities of daily living. To date, minimal research has examined the biomechanical effects of modified handles, or quantified the differences in ranges of motion (ROM) when using a standard versus a modified handle. The aim of this study was to quantify the ranges of motion (ROM) required for a healthy hand to use different adaptive spoons with electrogoniometry for the purpose of understanding the physiologic advantages that adapted spoons may provide patients with limited ROM.

Methods. Hand measurements included the distal interphalangeal joint (DIP), proximal interphalangeal joint (PIP), and metacarpophalangeal joint (MCP) for each finger and the interphalangeal (IP) and MCP joint for the thumb. Participants were 34 females age 18–30 (mean age 20.38 ± 1.67) with no previous hand injuries or abnormalities. Participants grasped spoons with standard handles, and spoons with handle diameters of 3.18 cm (1.25 inch), and 4.45 cm (1.75 inch). ROM measurements were obtained with an electrogoniometer to record the angle at each joint for each of the spoon handle sizes.

Results. A 3 × 3 × 4 repeated measures ANOVA (Spoon handle size by Joint by Finger) found main effects on ROM of Joint (F(2, 33) = 318.68, Partial η² = .95, p < .001), Spoon handle size (F(2, 33) = 598.73, Partial η² = .97, p < .001), and Finger (F(3, 32) = 163.83, Partial η² = .94, p < .001). As the spoon handle diameter size increased, the range of motion utilized to grasp the spoon handle decreased in all joints and all fingers (p < 0.01).

Discussion. This study confirms the hypothesis that less range of motion is required to grip utensils with larger diameter handles, which in turn may reduce challenges for patients with limited ROM of the hand.

Assessment of net knee moment-angle characteristics by instrumented hand-held dynamometry in children with spastic cerebral palsy and typically developing children

Background

The limited range of motion during walking in children with spastic cerebral palsy (SCP) may be the result of altered mechanical characteristics of muscles and connective tissues around the knee joint. Measurement of static net knee moment-angle relation will provide insights into these alterations, for which instrumented hand-held dynamometry may be applied.

The aims of this study were: (1) to test the measurement error of the estimated net knee moment-angle characteristics, (2) to determine the correlation between knee extension angle measurement at a standardized knee moment and popliteal angle from common physical examination and (3) to compare net knee moment–angle characteristics in SCP versus typically developing children.

Methods

With the child lying in sideward position, the knee was extended by moving the lower leg by a hand-held force transducer on a low friction cart. Force data were collected for a range of knee angles. Data were excluded when activity (EMG) levels of knee extensor and flexor muscles exceeded the EMG level during rest by more than two standard deviations. The net knee flexion moments were calculated from recorded force data and measured moment arm. Reliability for knee angles corresponding with 0.5, 1, 2, 3, and 4 Nm knee net flexion moments was assessed by standard error of measurements (SEM) and smallest detectable difference (SDD).

Results

For between day comparison, SEMs were about 5° and SDDs were below 14° for knee angles at 1-4 Nm net knee flexion moments. In SCP children, the knee angle measured at 4 Nm knee flexion moment was not related to the popliteal angle (r = 0.52). The slope at 4 Nm of the knee moment-angle curve in SCP children was significantly higher than that in typically developing children.

Conclusions

The presented knee hand-held dynamometry allows assessment of net knee flexion moment-knee angle characteristics in typically developing and SCP children and can be used to identify clinically relevant changes as a result of treatment. Overall stiffness of structures that contribute to the net knee flexion moment at the knee (i.e. muscles, tendons, ligaments) is elevated in SCP children.

Electronic supplementary material

The online version of this article (doi:10.1186/s12984-015-0056-y) contains supplementary material, which is available to authorized users.

Immediate Effects of Kinesiology Taping of Quadriceps on Motor Performance after Muscle Fatigued Induction

Objectives. The purpose of this cross-sectional single-blind study was to investigate the immediate effects of Kinesiology taping of quadriceps on motor performance after muscle fatigued induction. Design. Randomized controlled cross-sectional design. Subjects. Forty-five subjects participated in this study. Participants were divided into three groups: Kinesiology taping group, placebo taping group, and nontaping group. Methods. Subjects performed short-term exercise for muscle fatigued induction, followed by the application of each intervention. Peak torque test, one-leg single hop test, active joint position sense test, and one-leg static balance test were carried out before and after the intervention. Results. Peak torque and single-leg hopping distance were significantly increased when Kinesiology taping was applied (p < 0.05). But there were no significant effects on active joint position sense and single-leg static balance. Conclusions. We proved that Kinesiology taping is effective in restoring muscle power reduced after muscle fatigued induction. Therefore, we suggest that Kinesiology taping is beneficial for fatigued muscles.

Reliability and measurement precision of concentric-to-isometric and eccentric-to-isometric knee active joint position sense tests in uninjured physically active adults

OBJECTIVES

Proprioception is important because it is used by the central nervous system to mediate muscle control of joint stability, posture, and movement. Knee active joint position sense (AJPS) is one representation of knee proprioception. The purpose of this study was to establish the intra-tester, inter-session, test-retest reliability of concentric-to-isometric (seated knee extension; prone knee flexion) and eccentric-to-isometric (seated knee flexion; prone knee extension) knee AJPS tests in uninjured adults.

DESIGN

Descriptive.

SETTING

University laboratory.

PARTICIPANTS

Six males, six females (age 26.2 ± 5.7 years; height 171.1 ± 9.6 cm; mass 71.1 ± 16.6 kg).

MAIN OUTCOME MEASURES

Mean absolute error (AE; °); intraclass correlation coefficient (ICC) (2,1); standard error of measurement (SEM; °).

RESULTS

Mean AE ranged from 3.18° to 5.97° across tests. The ICCs and SEMs were: seated knee extension 0.13, 1.3°; prone knee flexion 0.51, 1.2°; seated knee flexion 0.31, 1.7°; prone knee extension 0.87, 1.4°.

CONCLUSIONS

The prone knee flexion and prone knee extension tests demonstrated moderate to good reliability. Prone knee flexion and prone knee extension AJPS tests may be useful in cross-sectional studies estimating how proprioception contributes to knee functional joint stability or prospective studies estimating the role of proprioception in the onset of knee injury.

Reproducibility of a knee and hip proprioception test in healthy older adults

BACKGROUND

Proprioception can be assessed by measuring joint position sense (JPS). Most studies have focused on JPS of the knee joint while literature for other joints especially for hip JPS is scarce. Although some studies have evaluated proprioception of the knee joint, the reproducibility of methods has rarely been investigated.

AIMS

To estimate intrasession reliability and agreement of an active-active JPS test for hip flexion/abduction and knee flexion in healthy older adults.

METHODS

Nineteen healthy older adults participated in this study. The proprioception of the hip (flexion and abduction) and knee (flexion) were assessed in both legs using the "active-active" reproduction technique. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), and limits of agreement (LOA) were estimated for relative angular error (RE), absolute angular error (AE), and variable angular error (VE).

RESULTS

Reliability of our JPS test was substantial to almost perfect for the RE for both joints and legs (ICC values ranging from 0.75 to 0.93). We also found that the ICC values for AE were substantial for knee flexion and hip abduction of the left and right leg. The ICC results of VE showed poor reliability for hip and knee joints. SEM and LOA values for hip abduction were generally lower than for hip and knee flexion, indicating lower measurement error or more precise scores for the proprioception test of hip abduction.

CONCLUSION(S)

Proprioceptive acuity of the knee and hip joints in healthy older adults can be reliably assessed with an active-active procedure in a standing position with respect to relative and absolute error.

Dynamic knee joint function in children with juvenile idiopathic arthritis (JIA)

BACKGROUND

Juvenile idiopathic arthritis (JIA) is a chronic illness with a high risk of developing long-term disability. Disease activity is currently being monitored and quantified by ACR core set. Here, joint inflammation is determined; however joint function is the crucial component for developing disability. The aim of this study was to quantify and compare dynamic joint function in healthy and arthritic knee joints and to evaluate response to improvement.

METHODS

A single center cohort study of consecutive children presenting to the rheumatology outpatient clinic was performed to measure dynamic knee joint function. Serial measures were performed if possible. Splint fixed electrogoniometers were used to measure dynamic knee joint function including ROM and flexion and extension torque.

RESULTS

A total of 54 children were tested including 44 with JIA, of whom eight had to be excluded for non-JIA-related knee problems. The study included 36 JIA patients of whom eight had strictly unilateral knee arthritis, and nine controls. Dynamic joint function ROM and torque depended on age and bodyweight, as demonstrated in healthy joints. ROM and torques were significant lower in arthritic compared to unaffected knee joints in children with unilateral arthritis and across the cohort. Importantly, extension torque was the most sensitive marker of impaired joint function. Follow up measurements detected responsiveness to change in disease activity.

CONCLUSIONS

Measuring dynamic joint function with electrogoniometers is feasible and objective. Active ROM and torque during flexion and extension of arthritic knee joints were significant lower compared to unaffected. In dynamic joint measurement extension torque is a sensitive marker for disease activity.

No correlation between joint position sense and force sense for measuring ankle proprioception in subjects with healthy and functional ankle instability

BACKGROUND

In general, ankle proprioception is most often evaluated by assessing joint position sense and force sense. However, in contrast to observational studies of joint position sense and force sense, no studies have examined the correlations between joint position sense and force sense. Therefore, the objective of this study was to investigate the correlations between joint position sense and force sense in subjects with healthy and functional ankle instability.

METHODS

Of the sixty nine subjects enrolled in the cross-sectional laboratory study, 35 had functional ankle instability and 34 were healthy subjects. Angle reproduction and force matching methods were used to quantify joint position sense and force sense of the ankle proprioception. These methods were also measured by using a flexible twin axis electrogoniometer and linear force, respectively. Three trials were performed at each angle and force. And then, absolute errors were calculated.

FINDINGS

Significant differences between the functional ankle instability and healthy group were found for absolute errors of plantar flexion, dorsiflexion, inversion, and eversion (P<0.05). No significant correlations between the joint position sense and force sense were found in subjects with both healthy, except for absolute errors of the eversion (r=0.652, P<0.05, r(2)=0.425), and functional ankle instability group (P>0.05).

INTERPRETATION

These findings suggest that it could be explained for deficits of ankle proprioception when angle reproduction and force matching tests to quantify joint position sense and force sense were applied and presented at the same time, not individually.

Assessment of Correlation between Electrogoniometer Measurements and Sports-Specific Movement in Karate Elites

PURPOSE

To examine the intra-rater reliability of knee movement data in sagital plane obtained from electrogoniometer (EGM) in a basic, sport-specific task of karate.

METHODS

A total of 23 elite karate athletes (13 females and 10 males; mean age of 16.10±1.26 yrs) participated in this study. The task was defined as performing three consecutive Zenkutsu-dachi in two sessions. The used EGM was a twin axis of Biometrics company. EGM curves were plotted in MATLAB software separately. The indices of three points in the plots corresponding to extremes of flexion and extension of knee in the first dachi were determined. There was also another (forth) point which was not in extremes of movement. As it was repeated in all curves, it was perceived as a biomechanical event and was assessed. The phases of movement between the points were scaled between 0 to 100% of activity.

RESULTS

Repeatability of the forth point index was assessed by intraclass correlation method. Intraclass correlation of the ratio in the first testing session was 0.666 and in second was 0.448. The interval between points were considered as phases of movement. After determining three phases of dachi, it was shown that these phases pertained a specific ratio of the total plot which were 48%, 36% and 16% of total respectively.

CONCLUSION

Dachi could be divided into three distinct phases; each of them should constitute a specific percent of the total in an elite athlete.

Validity and reliability of different kinematics methods used for bike fitting

The most common bike fitting method to set the seat height is based on the knee angle when the pedal is in its lowest position, i.e. bottom dead centre (BDC). However, there is no consensus on what method should be used to measure the knee angle. Therefore, the first aim of this study was to compare three dynamic methods to each other and against a static method. The second aim was to test the intra-session reliability of the knee angle at BDC measured by dynamic methods. Eleven cyclists performed five 3-min cycling trials; three at different seat heights (25°, 30° and 35° knee angle at BDC according to static measure) and two at preferred seat height. Thirteen infrared cameras (3D), a high-speed camera (2D), and an electrogoniometer were used to measure the knee angle during pedalling, when the pedal was at the BDC. Compared to 3D kinematics, all other methods statistically significantly underestimated the knee angle (P = 0.00; η(2) = 0.73). All three dynamic methods have been found to be substantially different compared to the static measure (effect sizes between 0.4 and 0.6). All dynamic methods achieved good intra-session reliability. 2D kinematics is a valid tool for knee angle assessment during bike fitting. However, for higher precision, one should use correction factor by adding 2.2° to the measured value.

Lower limb spasticity assessment using an inertial sensor: a reliability study

Spasticity is a common motor impairment in patients with neurological disorders that can prevent functional recovery after rehabilitation. In the clinical setting, its assessment is carried out using standardized clinical scales. The aim of this study was to verify the applicability of inertial sensors for an objective measurement of quadriceps spasticity and evaluate its test-retest and inter-rater reliability during the implementation of the Wartenberg pendulum test. Ten healthy subjects and 11 patients in vegetative state with severe brain damage were enrolled in this study. Subjects were evaluated three times on three consecutive days. The test-retest reliability of measurement was assessed in the first two days. The third day was devoted to inter-rater reliability assessment. In addition, the lower limb muscle tone was bilaterally evaluated at the knee joint by the modified Ashworth scale. The factorial ANOVA analysis showed that the implemented method allowed us to discriminate between healthy and pathological conditions. The fairly low SEM and high ICC values obtained for the pendulum parameters indicated a good test-retest and inter-rater reliability of measurement. This study shows that an inertial sensor can be reliably used to characterize leg kinematics during the Wartenberg pendulum test and provide quantitative evaluation of quadriceps spasticity.

A systematic review to determine the reliability of knee joint position sense assessment measures

BACKGROUND

The assessment of joint position sense (JPS) is the most widely used measurement of knee proprioceptive capability within the literature. However, it remains unclear what the most reliable method is to assess this. The purpose of this study was to determine the intra- and inter-rater reliability of the various methods used to assess knee JPS.

METHODS

A systematic review of published and unpublished literature sources was conducted up to June 2012. All studies principally assessing the reliability (intra- or inter-rater) or reproducibility of a JPS of the knee were included. The methodological quality of each study was reviewed using the Critical Appraisal Skills Programme tool.

RESULTS

A total of 18 studies were eligible, assessing the reliability of JPS with 456 knees. The reliability of four methods of JPS has been recorded: position replication using a model, image recorded angulation, electrogoniometry and dynamometry/angular motion chair. Intra-rater reliability was good for the assessment of JPS using photographs and digital images, and replicating knee position using a paper model, this was good but variable when electrogoniometry was used, and moderate but variable when assessed using dynamometry/angle motion chairs. The assessment of JPS by image recorded angulation, electrogoniometry and dynamometry/angular motion chair has demonstrated good inter-rater reliability.

CONCLUSIONS

Whilst JPS methods appear to have variable reliability, the four assessment methods should be further assessed with pathological populations such as those following patellar dislocation or anterior cruciate ligament rupture. This will better facilitate the generalisability of JPS assessment methods to inform clinical practice.

Does a mobile-bearing, high-flexion design increase knee flexion after total knee replacement?

This prospective randomised controlled double-blind trial compared two types of PFC Sigma total knee replacement (TKR), differing in three design features aimed at improving flexion. The outcome of a standard fixed-bearing posterior cruciate ligament-preserving design (FB-S) was compared with that of a high-flexion rotating-platform posterior-stabilised design (RP-F) at one year after TKR. The study group of 77 patients with osteoarthritis of the knee comprised 37 men and 40 women, with a mean age of 69 years (44.9 to 84.9). The patients were randomly allocated either to the FB-S or the RP-F group and assessed pre-operatively and at one year post-operatively. The mean post-operative non-weight-bearing flexion was 107° (95% confidence interval (CI) 104° to 110°)) for the FB-S group and 113° (95% CI 109° to 117°) for the RP-F group, and this difference was statistically significant (p = 0.032). However, weight-bearing range of movement during both level walking and ascending a slope as measured during flexible electrogoniometry was a mean of 4° lower in the RP-F group than in the FB-S group, with 58° (95% CI 56° to 60°) versus 54° (95% CI 51° to 57°) for level walking (p = 0.019) and 56° (95% CI 54° to 58°) versus 52° (95% CI 48° to 56°) for ascending a slope (p = 0.044). Further, the mean post-operative pain score of the Western Ontario and McMaster Universities Osteoarthritis Index was significantly higher in the RP-F group (2.5 (95% CI 1.5 to 3.5) versus 4.2 (95% CI 2.9 to 5.5), p = 0.043). Although the RP-F group achieved higher non-weight-bearing knee flexion, patients in this group did not use this during activities of daily living and reported more pain one year after surgery.

Is patient self-assessment of flexion after TKR able to identify risk of manipulation under anaesthesia?

BACKGROUND

Patient self-assessment of postoperative knee flexion following knee replacement was introduced at our institution. This protocol had a dual objective: improve follow-up and act as an early indicator to identify patients at risk of requiring a manipulation under anaesthesia. The aim of our study was to audit the use of this patient self-assessment tool and evaluate whether these outcomes were being achieved.

MATERIALS AND METHODS

A prospective audit of patients admitted for total knee replacements under the care of one orthopaedic consultant between April and October 2009. Participants were asked to measure and record daily maximum knee flexion whilst sitting, from discharge through to six-week follow-up. Patients were advised to contact the arthroplasty team if flexion reduced by 10° or more for three consecutive days. Patient's documented knee flexion was compared to that measured on discharge and at six weeks postoperatively by clinicians.

RESULTS

Seventy-nine participants (82 knees) were included with 61 participants (64 knees) returning data for analysis (78% compliance rate). Comparison of patient and clinician measurements showed a mean difference of +2° with limits of agreements from -12° to +15°. At a mean follow-up of six weeks maximum flexion (measured by clinician) was 99° (95%CI 97°, 102°) and 92% had a 90°flexion or greater. During the audit period, six patients met the criteria to contact the arthroplasty team, however none of them followed this instruction.

DISCUSSION

Patient self-assessment of knee flexion at home with a simple goniometer was accurate enough to be useful and 92% of patients reached 90° maximum flexion at six weeks. However this self-assessment method was not successful as an early indicator to identify patients at risk of requiring a manipulation under anaesthesia. Future studies into alternative identifiers are required.

LEVEL OF EVIDENCE

Level III. Investigating a diagnostic test.

Comparison of Strain-Gage and Fiber-Optic Goniometry for Measuring Knee Kinematics During Activities of Daily Living and Exercise

There is increasing interest in wearable sensor technology as a tool for rehabilitation applications in community or home environments. Recent studies have focused on evaluating inertial based sensing (accelerometers, gyroscopes, etc.) that provide only indirect measures of joint motion. Measurement of joint kinematics using flexible goniometry is more direct, and still popular in laboratory environments, but has received little attention as a potential tool for wearable systems. The aim of this study was to compare two goniometric devices: a traditional strain-gauge flexible goniometer, and a fiberoptic flexible goniometer, for measuring dynamic knee flexion/extension angles during activity of daily living: chair rise, and gait; and exercise: deep knee bends, against joint angles computed from a “gold standard” Vicon motion tracking system. Six young adults were recruited to perform the above activities in the lab while wearing a goniometer on each knee, and reflective markers for motion tracking. Kinematic data were collected simultaneously from the goniometers (one on each leg) and the motion tracking system (both legs). The results indicate that both goniometers were within 2–5 degrees of the Vicon angles for gait and chair rise. For some deep knee bend trials, disagreement with Vicon angles exceeded ten degrees for both devices. We conclude that both goniometers can record ADL knee movement faithfully and accurately, but should be carefully considered when high (>120 deg) knee flexion angles are required.

The influence of heel height on sagittal plane knee kinematics during landing tasks in recreationally active and athletic collegiate females

PURPOSE

To determine if heel height alters sagittal plane knee kinematics when landing from a forward hop or drop landing.

BACKGROUND

Knee angles close to extension during landing are theorized to increase ACL injury risk in female athletes.

METHODS

Fifty collegiate females performed two single-limb landing tasks while wearing heel lifts of three different sizes (0, 12 & 24 mm) attached to the bottom of a sneaker. Using an electrogoniometer, sagittal plane kinematics (initial contact [KA(IC)], peak flexion [KA(Peak)], and rate of excursion [RE]) were examined. Repeated measures ANOVAs were used to determine the influence of heel height on the dependent measures.

RESULTS

Forward hop task- KA(IC) with 0 mm, 12 mm, and 24 mm lifts were 8.88±6.5, 9.38±5.8 and 11.28±7.0, respectively. Significant differences were noted between 0 and 24 mm lift (p<.001) and 12 and 24 mm lifts (p=.003), but not between the 0 and 12 mm conditions (p=.423). KA(Peak) with 0 mm, 12 mm, and 24 mm lifts were 47.08±10.9, 48.18±10.3 and 48.88±9.7, respectively. A significant difference was noted between 0 and 24 mm lift (p=.004), but not between the 0 and 12 mm or 12 and 24 mm conditions (p=.071 and p=.282, respectively). The RE decreased significantly from 2128/sec±52 with the 12 mm lift to 1958/sec±55 with the 24 mm lift (p=.004). RE did not differ from 0 to 12 or 0 to 24 mm lift conditions (p=.351 and p=.086, respectively). Jump-landing task- No significant differences were found in KA(IC) (p=.531), KA(Peak) (p=.741), or the RE (p=.190) between any of the heel lift conditions.

CONCLUSIONS

The addition of a 24 mm heel lift to the bottom of a sneaker significantly alters sagittal plane knee kinematics upon landing from a unilateral forward hop but not from a drop jump.