Healthy knee KT1000 measurements of anterior tibial translation have significant variation.

PURPOSE: The most commonly used arthrometer for measuring and reporting anterior tibial translation after anterior cruciate ligament reconstruction is the KT1000. Reports on its consistency and reproducibility vary in the literature, but it remains the "gold standard". The purpose of this study was to assess agreement of KT1000 measurements in a daily clinical setting. METHODS: A retrospective analysis of anterior knee translation in the healthy knee of 770 patients over a 17-year time period was performed. In this cohort, a total of 24 investigators performed 1890 measurement sets at 89 Newtons (N), 134N and at maximum manual force (MMax) level. To assess the inter- and intra-observer agreement, the intraclass-correlation coefficient (ICC) was calculated. The "investigator effect" was a difference between two examiners in the same patient and the "device effect'' a difference within one examiner in the same patient. Minimally important difference (MID) was calculated as 0.5 of the standard deviation. RESULTS: Thirteen investigators were female, performing 1099 measurements and 11 were male, performing 791 measurements. ICC ranged between 0.558 and 0.644. At the MMax level, male investigators had a higher mm reading than female investigators (p < 0.001). Increased experience did not correlate with a higher ICC. MID ranged between 0.85 and 1.65 mm. CONCLUSION: This study investigated the KT1000 arthrometer in a clinical setting with a large number of investigators. This device delivers moderate agreement of results. Both the device and investigator effect are present. The MMax level has shown the lowest agreement and a dependency on the investigator gender. LEVEL OF EVIDENCE: Level III diagnostic study.

The Cut-off Values for the Diagnosis of Hamstring Shortness and Related Factors

Background: Hamstrings are one of the most frequently evaluated muscle groups for flexibility in the lower extremity. Passive and active knee extension angle values are used as an indirect indicator of hamstring flexibility. However, the lack of consensus on the cut-off values leads to the use of inconsistent angle values in determining the hamstring tightness. Aims: To establish the normative and cut-off values of the passive and active knee extension angles for healthy young adults and to determine the associated factors including the quadriceps strength. Study Design: A cross-sectional study. Methods: A total of 123 volunteer university students, aged 18-24 years, who met the inclusion criteria were included in this study. Passive and active knee extension assessments of the subjects were performed. Subsequently, on the next day, both knee extensor concentric muscle strength of the participants was measured in the isokinetic system. The knee extension angles and the knee extensor strength were recorded as the mean values of the right and the left sides. Results: Passive knee extension angles of 17.1°±9.1° and 9.8°±5.7° and active knee extension angles of 17.8°±9.1° and 13.4°±6° were described as normative values in men and women, respectively. The cut-off values for the diagnosis of hamstring shortness were as follows: passive knee extension angle >32.2° for males and >19.2° for females and active knee extension angle >33.0° for males and >23.4° for females. A significant positive correlation was observed between knee extension angles and isokinetic knee extensor muscle strength in all participants. The knee extension angle and hamstring flexibility were not affected by dominance. Conclusion: The knee extension angles of healthy young people seem to be lower than the results currently reported in the literature. There s a positive correlation between knee extension angles and isokinetic knee extensor muscle strength.

Postoperative Anteroposterior Laxity Influences Subjective Outcome After Total Knee Arthroplasty.

BACKGROUND: We hypothesized that postoperative anteroposterior (AP) stability of the knee correlates with patient-reported clinical outcome and knee function after total knee arthroplasty (TKA). METHODS: This study enrolled 110 knees in 81 patients after TKA. AP laxity was measured with a KS Measure Arthrometer at 30°, 60°, and 90° flexion, which was confirmed with a goniometer. We assessed knee pain and function by using the Knee Society Function Score (KSS) and Knee Injury and Osteoarthritis Outcome Score (KOOS). Correlations among AP translation values and KOOS subscale scores (pain symptom, activities of daily living, and knee-related quality of life), KSS, and range of motion (ROM) were analyzed. RESULTS: The mean follow-up period for the assessment of the KOOS was 4.4 ± 2.2 years (range, 1.1-11.5 years). Twenty-five knees had posterior-stabilized fixed-bearing TKA, and 85 knees had posterior-stabilized mobile-bearing TKA. The mean KSS functional score and mean ROM were 96.3 ± 5.7 (range, 75-100) and 121.6° ± 14.4° (range, 90°-145°), respectively. The mean AP laxity was 4.5 ± 2.2 mm, 3.6 ± 1.9 mm, and 3.0 ± 1.9 mm at 30°, 60°, and 90° knee flexion, respectively. A significant inverse association was observed between AP laxity at 60° knee flexion and KOOS pain (P = .02∗, R2 = 0.05), but no significant association was found between AP laxity and other KOOS subscale score, KSS, and ROM. CONCLUSION: We found that the AP laxity at 60° knee flexion in this study significantly correlated with patient-reported pain. The observed AP laxity can be considered as a register of normal AP translations after arthroplasty.

Role of pain in measuring shoulder strength abduction and flexion with the Constant-Murley score.

OBJECTIVES: The Constant-Murley score (CS) has been used for more than 25 years to assess shoulder function. Strength by itself accounts for 25% of the total score. The measurement at 90° abduction seems to be sometimes limited by pain, particularly with tendinopathy or subacromial impingement. We compared the assessment of isometric strength in anterior forward flexion and abduction and its effect on pain and total CS. METHODS: Strength was assessed by CS at both 90° forward flexion and abduction in the scapular plane by using an Isobex dynamometer, the first position tested being randomized. Pain was assessed on a 100-mm visual analog scale (VAS) and total CS was assessed. RESULTS: We included 54 patients with unilateral shoulder problems; 50% had rotator cuff injury. Mean strength on the affected side was 4.7±2.5kg in forward flexion and 4.6±2.8kg in abduction. Induced pain and total CS did not differ between the 2 positions tested. CONCLUSIONS: Strength can be measured by the CS in forward flexion or abduction, because the measurement does not affect strength, pain intensity or total score. The choice of direction for measurement should be based on the underlying pathology, related contraindications and patient preference.

Inter and intra-rater reliability of mobile device goniometer in measuring lumbar flexion range of motion.

BACKGROUND: Evaluation of range of motion (ROM) is integral part of assessment of musculoskeletal system. This is required in health fitness and pathological conditions; also it is used as an objective outcome measure. Several methods are described to check spinal flexion range of motion. Different methods for measuring spine ranges have their advantages and disadvantages. Hence, a new device was introduced in this study using the method of dual inclinometer to measure lumbar spine flexion range of motion (ROM). OBJECTIVES: To determine Intra and Inter-rater reliability of mobile device goniometer in measuring lumbar flexion range of motion. METHOD: iPod mobile device with goniometer software was used. The part being measure i.e the back of the subject was suitably exposed. Subject was standing with feet shoulder width apart. Spinous process of second sacral vertebra S2 and T12 were located, these were used as the reference points and readings were taken. Three readings were taken for each: inter-rater reliability as well as the intra-rater reliability. Sufficient rest was given between each flexion movement. RESULTS: Intra-rater reliability using ICC was r=0.920 and inter-rater r=0.812 at CI 95%. Validity r=0.95. CONCLUSION: Mobile device goniometer has high intra-rater reliability. The inter-rater reliability was moderate. This device can be used to assess range of motion of spine flexion, representing uni-planar movement.

Hypermobility among school children aged five to eight years: the Hospital del Mar Criteria gives higher prevalence for hypermobility than the Beighton score.

OBJECTIVES: The purpose was to investigate the distribution of hypermobility among school children aged five to eight years. METHODS: One hundred and twenty-eight participants were assessed using the Beighton score and the Hospital del Mar criteria. RESULTS: With the Beighton score using the cut-off ≥4, the prevalence was 12%, and with the Hospital del Mar criteria the prevalence was 34%. There were significantly higher scores for females on both the Beighton (p=0.01) and Hospital del Mar criteria (p<0.0001). The youngest children aged five to six years scored higher compared with the seven- and eight-year-olds (p=0.016). The knee flexion was most likely to be hypermobile (97%), followed by shoulder rotation (80%), thumb (31%), elbow (27%), metatarsal-phalangeal (16%), hip (15.5%), fingers (10%) or knee (10%), ankle (6%), trunk (4%) and patella (2%). CONCLUSIONS: Gender and probably age must be taken into account when children are assessed for hypermobility. The Hospital del Mar criteria need to be modified for some of the motions.

Wrist electrogoniometry: are current mathematical correction procedures effective in reducing crosstalk in functional assessment?

BACKGROUND: The recording of human movement is an essential requirement for biomechanical, clinical, and occupational analysis, allowing assessment of postural variation, occupational risks, and preventive programs in physical therapy and rehabilitation. The flexible electrogoniometer (EGM), considered a reliable and accurate device, is used for dynamic recordings of different joints. Despite these advantages, the EGM is susceptible to measurement errors, known as crosstalk. There are two known types of crosstalk: crosstalk due to sensor rotation and inherent crosstalk. Correction procedures have been proposed to correct these errors; however no study has used both procedures in clinical measures for wrist movements with the aim to optimize the correction. OBJECTIVE: To evaluate the effects of mathematical correction procedures on: 1) crosstalk due to forearm rotation, 2) inherent sensor crosstalk; and 3) the combination of these two procedures. METHOD: 43 healthy subjects had their maximum range of motion of wrist flexion/extension and ulnar/radials deviation recorded by EGM. The results were analyzed descriptively, and procedures were compared by differences. RESULTS: There was no significant difference in measurements before and after the application of correction procedures (P<0.05). Furthermore, the differences between the correction procedures were less than 5° in most cases, having little impact on the measurements. CONCLUSIONS: Considering the time-consuming data analysis, the specific technical knowledge involved, and the inefficient results, the correction procedures are not recommended for wrist recordings by EGM.

Wrist electrogoniometry: are current mathematical correction procedures effective in reducing crosstalk in functional assessment? / Eletrogoniometria de punho: procedimentos matemáticos usuais de correção são eficazes para reduzir crosstalk em avaliação funcional?

BACKGROUND: The recording of human movement is an essential requirement for biomechanical, clinical, and occupational analysis, allowing assessment of postural variation, occupational risks, and preventive programs in physical therapy and rehabilitation. The flexible electrogoniometer (EGM), considered a reliable and accurate device, is used for dynamic recordings of different joints. Despite these advantages, the EGM is susceptible to measurement errors, known as crosstalk. There are two known types of crosstalk: crosstalk due to sensor rotation and inherent crosstalk. Correction procedures have been proposed to correct these errors; however no study has used both procedures in clinical measures for wrist movements with the aim to optimize the correction. OBJECTIVE: To evaluate the effects of mathematical correction procedures on: 1) crosstalk due to forearm rotation, 2) inherent sensor crosstalk; and 3) the combination of these two procedures. METHOD: 43 healthy subjects had their maximum range of motion of wrist flexion/extension and ulnar/radials deviation recorded by EGM. The results were analyzed descriptively, and procedures were compared by differences. RESULTS: There was no significant difference in measurements before and after the application of correction procedures (P<0.05). Furthermore, the differences between the correction procedures were less than 5° in most cases, having little impact on the measurements. CONCLUSIONS: Considering the time-consuming data analysis, the specific technical knowledge involved, and the inefficient results, the correction procedures are not recommended for wrist recordings by EGM.

CONTEXTUALIZAÇÃO: O registro do movimento humano é requisito fundamental para análises biomecânicas, clínicas e ocupacionais, permitindo avaliar variações posturais, riscos e aprimoramento de programas preventivos e de reabilitação em Fisioterapia. O eletrogoniômetro flexível (EGM), considerado um equipamento confiável e acurado, é utilizado para o registro dinâmico de diferentes articulações. Apesar das vantagens, o EGM é suscetível de erros de medida, denominados crosstalk. Atualmente, são conhecidos dois tipos de crosstalk, o crosstalk devido à rotação do sensor e o crosstalk inerente. Procedimentos de correção foram propostos para a correção desses erros, no entanto nenhum estudo utilizou ambos os procedimentos em medidas clínicas dos movimentos do punho, visando otimizar a correção. OBJETIVO: Avaliar o efeito de procedimentos matemáticos atualmente empregados para correção do: 1) crosstalk devido à rotação do antebraço; 2) crosstalk inerente aos sensores e 3) combinação desses dois procedimentos. MÉTODO: Quarenta e três indivíduos saudáveis tiveram as amplitudes máximas dos movimentos de flexão/extensão e desvios ulnar/radial do punho registrados pelos EGM. Os resultados foram analisados de forma descritiva, e os procedimentos foram comparados por diferenças. RESULTADOS: Não houve alteração significativa nas medidas após a aplicação dos procedimentos de correção (P<0,05). Além disso, as diferenças entre os procedimentos de correção foram inferiores a 5° para a maioria dos casos, indicando pouco impacto sobre as medidas. CONCLUSÕES: Considerando o tempo de processamento, o conhecimento técnico específico exigido e os ineficazes resultados obtidos, desaconselha-se a aplicação desses procedimentos na correção de registros eletrogoniométricos do punho.

Trunk asymmetry in one thousand school children aged 7-10 years.

Screening for idiopathic scoliosis is not very popular in Poland. Some Polish towns and cities have prevention programmes aimed at discovering spine dysfunctions and disorders in children and adolescents. An assessment of the angle of trunk rotation (ATR) is a reliable, effective and non-invasive action that allows use to determine trunk asymmetry. Since then the scoliometer has spread throughout the United States and other countries, where it is a popular device in the clinical practice of diagnosing scoliosis. 9,500 children aged 7-10 were examined as part of a disease prevention programme entitled "Poznan Chooses Health - Bad Posture Prophylaxis in Class I-IV Primary School Children in Poznan". The analysis included results obtained in 2010 during initial posture assessment in 1000 children, Trunk asymmetry was measured by means of the Bunnell scoliometer. The measurement of the angle of trunk rotation was the spontaneous standing position with use the scoliometer during bending (Adams forward test) at three levels: proximal thoracic, main thoracic and lumbar. For the proximal thoracic section the 0° ATR value was found in 6 children, values of 1°-3° were recorded in 883 children, values of 4°-6° in 108 children, 7° or higher in 3 of the examined children. For the main thoracic section the 0° ATR value was found in 101 children, values of 1°-3° were recorded in 735 children, 4°-6° in 155 children, 7° or higher in 9 of the examined children. For the lumbar section ATR values of 0°, 1°-3°, 4°-6°, and 7° or higher were found, respectively, in 147, 883, 108 and 11 of the examined children.

[Do German-speaking paediatric orthopaedic surgeons agree on diagnostics and treatment of the neonatal hip?]. / Diagnostik und Therapie der Säuglingshüfte - sind sich die deutschsprachigen Kinderorthopäden einig?

BACKGROUND: Ultrasound examination of the neonatal hip has been an integral part of the German programme for the "early detection of disease in childhood" since 01.01.1996. The aim of this study is to determine if any consensus exists among German-speaking paediatric orthopaedic specialists concerning diagnosis and treatment of the neonatal hip 15 years after legal implementation of hip ultrasound screening by the Graf technique. MATERIALS AND METHODS: A questionnaire was sent to all members of the German speaking Association of Paediatric Orthopaedic Surgeons (Vereinigung für Kinderorthopädie - VKO). The query included questions concerning education and field of activity of the member as well as information on the diagnostics of neonatal hip with regard to examiner, technical equipment, and type of screening. In addition, four cases were presented with clinical history, clinical findings, and rateable Graf sonogram (case 1: 3 days old ♀, type D; case 2: 2 days old ♀, type IV; case 3: 4 weeks old ♀, type II a; case 4: 4 months old ♀, type III a) and a treatment recommendation was requested for each case. RESULTS: 78 of 179 contactable VKO members participated in this survey. 75.6 % of the participants are specialists with additional qualification in paediatric orthopaedic surgery. 68 % of the participants work in a hospital. As stated by 61.5 % of the participants the ultrasound examination of the neonatal hip is primarily done by orthopaedic surgeons. One participant stated that the examination is performed primarily by medical-technical assistants. The majority of participants use a 7.5-MHz linear transducer for ultrasound examination, a positioning device according to Graf and a foot switch as technical equipment. State-of-the-art equipment as recommended by Graf including in addition to the above mentioned an upright image display and a transducer guiding arm system is available to only 21.8 % of the participating VKO members. 23 of 50 participants stated that a general screening is performed at their institution where all newborns get an ultrasound examination within the first week of life regardless of medical history and clinical findings. Therapeutic recommendations for the first case (type D hip) were in 15.4 % wait and check by some colleagues, supplemented by double diapering. 56.4 % would use a flexion-abduction splint and 26.9 % would perform reduction with consecutive retention. To treat case 2 (type IV hip) 3.8 % of participants suggest a flexion-abduction splint and 88.5 % reduction and retention. Concerning the type of reduction the participants do not agree. Pavlik harness as well as closed reduction under anaesthesia or without anaesthesia is recommended. In case 3 (type II a hip) 67.9 % of the colleagues suggest to wait and check, some with supplementary double diapering. 25.6 % suggest a flexion-abduction splint. One colleague would prescribe a Pavlik harness. In case 4 (type III a hip) 14.1 % of the participants suggest a flexion-abduction splint, 80.8 % reduction and retention as described before with disagreement concerning the preferred type of reduction. On combining the therapeutic suggestions for all four cases, 66 % of the participants recommend a type of treatment that is concordant with Graf's guidelines. CONCLUSION: Despite the existence of clear recommendations the German-speaking paediatric orthopaedic surgeons are quite discordant concerning diagnostics and treatment of the neonatal hip. Uncertainty particularly concerning the evaluation of sonograms of physiologically immature and dysplastic-unstable hips bears the risk of overtreatment as well as of delayed diagnosis of hip dysplasia.

[Evaluation of anterior knee laxity on MRI]. / Évaluation de la laxité antérieure du genou en IRM: la laxi-IRM.

PURPOSE: Evaluation of the ACL and anterior knee laxity on MR during anterior tibial translation. PATIENTS AND METHODS: Three groups were identified based on clinical and arthrometric (KT-1000) data: normal ACL (n=12), complete tear (n=10) and partial tear (n=20). MRI was performed without and with anterior tibial translation (pneumatic device) with morphological and laximetric analysis: drawer tests and dynamic evaluation of ligamentous tension. RESULTS: Intra- and inter-observer reproducibility was excellent, correlated to arthrometric data and clinical tests (Lachman, pivot shift). The difference between the drawer signs of normal subjects and patients with ACL tear was significant for a threshold value of 1,1mm for the anterior drawer (sensitivity: 93.33%, specificity: 91.7%) and 2.8 mm for the posterior drawer (sensitivity: 86.7%, specificity: 100%). Dynamic evaluation of ligamentous tension was also reproducible, statistically correlated to the MR drawer tests and reliable for the diagnosis of ACL lesions. In this preliminary study, the distinction between complete and partial ACL tears could not be detected. CONCLUSION: Anterior cruciate ligament function can be demonstrated on MR. The predictive value of this morphological and functional association should be determined in the management of patients with partial tears.

Cluster analysis of movement patterns in multiarticular actions: a tutorial.

The present paper proposes a technical analysis method for extracting information about movement patterning in studies of motor control, based on a cluster analysis of movement kinematics. In a tutorial fashion, data from three different experiments are presented to exemplify and validate the technical method. When applied to three different basketball-shooting techniques, the method clearly distinguished between the different patterns. When applied to a cyclical wrist supination-pronation task, the cluster analysis provided the same results as an analysis using the conventional discrete relative phase measure. Finally, when analyzing throwing performance constrained by distance to target, the method grouped movement patterns together according to throwing distance. In conclusion, the proposed technical method provides a valuable tool to improve understanding of coordination and control in different movement models, including multiarticular actions.

Intra and inter-rater reliability of a goniometric lower trunk rotation measurement.

OBJECTIVES: Limited lower trunk rotation, which includes rotation of the lumbar spine, may hinder or even prevent functional activities. Currently, due to the lack of reliable, valid, and clinically useful tests, there is no standard objective measure of lower trunk rotation that can be easily performed in the clinic. The purpose of this study was to establish a standard protocol and to determine inter-rater and intra-rater reliability for a goniometric measurement developed to measure lower trunk rotation. METHODS: Lower trunk rotation was measured using a specific, goniometric method in 41 subjects. Each subject was measured 6 times by 2 different examiners for a total of 12 measurements. RESULTS: Pearson correlation coefficients indicate good intra-rater reliability ranging from 0.59 to 0.82 for right rotation (P< 0.001) and 0.76 to 0.82 for left rotation (P< 0.001), as well as good inter-rater reliability ranging from 0.62 to 0.83 with right rotation (P< 0.001) and 0.75 to 0.77 for left rotation (P< 0.001). CONCLUSION: This measure of trunk rotation may be useful for objectively documenting lower trunk rotation.

Development of lower limb range of motion from early childhood to adolescence in cerebral palsy: a population-based study.

BACKGROUND: The decreasing range of joint motion caused by insufficient muscle length is a common problem in children with cerebral palsy (CP), often worsening with age. In 1994 a CP register and health care programme for children with CP was initiated in southern Sweden. The aim of this study was to analyse the development of the passive range of motion (ROM) in the lower limbs during all the growth periods in relation to gross motor function and CP subtype in the total population of children with CP. METHODS: In total, 359 children with CP born during 1990-1999, living in the southernmost part of Sweden in the year during which they reached their third birthday and still living in the area in the year of their seventh birthday were analysed. The programme includes a continuous standardized follow-up with goniometric measurements of ROM in the lower limbs. The assessments are made by each child's local physiotherapist twice a year until 6 years of age, then once a year. In total, 5075 assessments from the CPUP database from 1994 to 1 January 2007 were analysed. RESULTS: The study showed a decreasing mean range of motion over the period 2-14 years of age in all joints or muscles measured. The development of ROM varied according to GMFCS level and CP subtype. CONCLUSION: We found a decreasing ROM in children with CP from 2-14 years of age. This information is important for both the treatment and follow-up planning of the individual child as well as for the planning of health care programmes for all children with CP.

Development and validation of a user-friendly data logger (SUDALS) for use with flexible electrogoniometers to measure joint movement in clinical trials.

OBJECTIVE: Our aim was to develop and validate a user-friendly data logger system (SUDALS) for use with flexible electrogoniometry. METHODS: Data pertaining to flexion/extension of the knee from 10 normal subjects were collected during a range of activities of daily living (ADL) such as walking, ascending and descending stairs, getting in and out of a chair and deep squatting. The accuracy, reliability and reproducibility of the data from SUDALS were verified by comparing against the data simultaneously collected from the Vicon system. RESULTS: The results of these studies indicate that the SUDALS together with flexible electrogoniometers is able to produce stable, precise, accurate and repeatable knee flexion/extension angles with little variation existing between the data produced by the SUDALS, the Vicon system and that reported in the literature. CONCLUSION: The SUDALS together with flexible electrogoniometers is a useful clinical tool, capable of recording knee flexion/extension angles accurately during ADL.

Does soccer participation lead to genu varum?

Little is known about the relationship between sport participation and body adaptations during growth. Our aim was to investigate whether soccer participation in youth is associated with the degree of genu varum. The design was a retrospective cohort study. Three hundred and thirty-six male soccer players, and 458 male non-soccer players (aged from 8 to 18) were recruited and included in the study. The intercondylar (IC) or intermalleolar (IM) distance were clinically measured with a specifically designed instrument. The results of this study revealed a statistically significant increase in degree of genu varum in both groups from the age of 14. However, at the age of 16-18 years a significant higher degree of genu varum was observed in the soccer players compared to the non-soccer players (P = 0.028). Intense soccer participation increases the degree of genu varum in males from the age of 16. Since genu varum predisposes to injuries, efforts to reduce the development of genu varum in male soccer players are warranted.

Assessing individual agreement.

Evaluating agreement between measurement methods or between observers is important in method comparison studies and in reliability studies. Often we are interested in whether a new method can replace an existing invasive or expensive method, or whether multiple methods or multiple observers can be used interchangeably. Ideally, interchangeability is established only if individual measurements from different methods are similar to replicated measurements from the same method. This is the concept of individual equivalence. Interchangeability between methods is similar to bioequivalence between drugs in bioequivalence studies. Following the FDA guidelines on individual bioequivalence, we propose to assess individual agreement among multiple methods via individual equivalence using the moment criteria. In the case where there is a reference method, we extend the individual bioequivalence criteria to individual equivalence criteria and propose to use individual equivalence coefficient (IEC) to compare multiple methods to one or multiple references. In the case where there is no reference method available, we propose a new IEC to assess individual agreement between multiple methods. Furthermore, we propose a coefficient of individual agreement (CIA) that links the IEC with two recent agreement indices. A method of moments is used for estimation, where one can utilize output from ANOVA models. The nonparametric and bootstrap approaches are used for inference. Five examples are used for illustration.

Comparison of concordance correlation coefficient and coefficient of individual agreement in assessing agreement.

In method comparison and reliability studies, it is often important to assess agreement between multiple measurements made by different methods, devices, laboratories, observers, or instruments. For continuous data, the concordance correlation coefficient (CCC) is a popular index for assessing agreement between multiple methods on the same subject where none of the methods is treated as reference. Barnhart et al. (2007) proposed coefficient of individual agreement (CIA) to assess individual agreement between multiple methods for situations with and without a reference method extending the concept of individual bioe-quivalence from the FDA 2001 guidelines. In this paper, we propose a new CCC for assessing agreement between multiple methods where one of the methods is treated as reference. We compare the properties of the CCC and CIA and their dependency on the relative magnitude of between-subject variability and within-subject variability. The relationship between CCC and CIA as well as the impact of between-subject variability are presented algebraically and graphically. Several examples are presented to explain the interpretation of the CCC and CIA values.

Measurement of active rotation in standing: reliability of a simple test protocol.

Interrater and intrarater reliability were evaluated for a test measuring active rotation range in a standing position. Subjects stood with their feet comfortably apart while a horizontal bar rested on their shoulders. A plumb bob attached to the end of the bar was allowed to drop to the floor, indicating maximal rotation range achieved. Two raters measured 24 subjects (M age = 35 +/- 14 yr.), who were sedentary office workers and active recreational golfers, on two occasions separated by two weeks to obtain values for left and right trunk rotation range. The test had good intrarater and interrater reliabilities, with standard error of measurement values varying from 5.6 degrees to 8.6 degrees against an overall mean range of 128 degrees. This simple active rotation test requires inexpensive equipment and could be incorporated into clinical examinations when there is a need to assess active rotation in standing with minimal constraints.