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BACKGROUND: Objective gait analysis that fully captures the multi-segmental foot movement of a clubfoot may help in early identification of a relapse clubfoot. Unfortunately, this type of objective measure is still lacking in a clinical setting and it is unknown how it relates to clinical assessment. RESEARCH QUESTION: The aim of this study was to identify differences in total gait and foot deviations between clubfoot patients with and without a relapse clubfoot and to evaluate their relationship with clinical status. METHODS: In this study, Ponseti-treated idiopathic clubfoot patients were included and divided into clubfoot patients with and without a relapse. Objective gait analysis was done resulting in total gait and foot scores and clinical assessment was performed using the Clubfoot Assessment Protocol (CAP). Additionally, a new clubfoot specific foot score, the clubFoot Deviation Index (cFDI*), was calculated to better capture foot kinematics of clubfoot patients. RESULTS: Clubfoot patients with a relapse show lower total gait quality (GDI*) and lower clinical status defined by the CAP than clubfoot patients without a relapse. Abnormal cFDI* was found in relapse patients, reflected by differences in corresponding variable scores. Moderate relationships were found for the subdomains of the CAP and total gait and foot quality in all clubfoot patients. SIGNIFICANCE: A new total foot score was introduced in this study, which was more relevant for the clubfoot population. The use of this new foot score (cFDI*) besides the GDI*, is recommended to identify gait and foot motion deviations. Along with clinical assessment, this will give an overview of the overall status of the complex, multi-segmental aspects of a (relapsed) clubfoot. The relationships found in this study suggest that clinical assessment might be indicative of a deviation in total gait and foot pattern, therefore hinting towards personalised screening for better treatment decision making. ispartof: GAIT & POSTURE vol:97 pages:210-215 ispartof: location:England status: published

Purpose Fear of movement (kinesiophobia) is a major limiting factor in the return to pre-injury sport level after anterior cruciate ligament reconstruction (ACLR). The aim of this study was to gain insight into the prevalence of kinesiophobia pre-ACLR, 3 months post-ACLR and 12 months post-ACLR. Furthermore, the preoperative predictability of kinesiophobia at 3 months post-ACLR was addressed. Methods A retrospective study with data, which were prospectively collected as part of standard care, was conducted to evaluate patients who underwent ACLR between January 2017 and December 2018 in an orthopaedic outpatient clinic. Patient characteristics (age, sex, body mass index), injury-to-surgery time, preoperative pain level (KOOS pain subscale) and preoperative knee function (IKDC-2000) were used as potential predictor variables for kinesiophobia (TSK-17) at 3 months post-ACLR in linear regression analysis. Results The number of patients with a high level of kinesiophobia (TSK > 37) reduced from 92 patients (69.2%) preoperatively to 44 patients (43.1%) 3 months postoperatively and 36 patients (30.8%) 12 months postoperatively. The prediction model, based on a multivariable regression analysis, showed a positive correlation between four predictor variables (prolonged injury-to-surgery time, high preoperative pain level, male sex and low body mass index) and a high level of kinesiophobia at 3 months postoperatively (R2 = 0.384, p = 0.02). Conclusion The prevalence of kinesiophobia decreases during postoperative rehabilitation, but high kinesiophobia is still present in a large portion of the patients after ACLR. Timing of reconstruction seems to be the strongest predictor for high kinesiophobia 3 months post-ACLR. This study is the first step in the development of a screening tool to detect patients with kinesiophobia after ACLR. Identifying patients preoperatively opens the possibility to treat patients and thereby potentially increase the return to pre-injury sport level rate after ACLR. Level of evidence III.

BACKGROUND: Altered muscle-tendon properties in clubfoot patients could play a role in the occurrence of a relapse and negatively affect physical functioning. However, there is a lack of literature about muscle-tendon properties of clubfoot relapse patients. RESEARCH QUESTION: The aim of this study was to determine whether the muscle architecture of the medial gastrocnemius and the morphology of the Achilles tendon differ between typically developing children (TDC) and clubfoot patients with and without a relapse clubfoot and to determine the relationships between morphological and functional gait outcomes. METHODS: A cross-sectional study was carried out in clubfoot patients treated according to the Ponseti method and TDC aged 4-8 years. A division between clubfoot patients with and without a relapse was made. Fifteen clubfoot patients, 10 clubfoot relapse patients and 19 TDC were included in the study. Morphologic properties of the medial head of the Gastrocnemius muscle and Achilles tendon were assessed by ultrasonography. Functional gait outcomes were assessed using three-dimensional gait analysis. Mean group differences were analysed with ANOVA and non-parametric alternatives. Relationships between functional and morphologic parameters were determined for all clubfoot patients together and for TDC with Spearman's rank correlation. RESULTS: Morphological and functional gait parameters did not differ between clubfoot patients with and without a relapse, with exception of lower maximal dorsiflexor moment in clubfoot relapse patients. Compared to TDC, clubfoot and relapse patients did show lower functional gait outcomes, as well as shorter and more pennate muscles with a longer Achilles tendon. In all clubfoot patients, this longer relative tendon was related to higher ankle power and plantarflexor moment. SIGNIFICANCE: In clubfoot and relapse patients, abnormalities in morphology did not always relate to worse functional gait outcomes. Understanding these relationships in all clubfoot patients may improve the knowledge about clubfoot and aid future treatment planning. ispartof: GAIT & POSTURE vol:93 pages:47-53 ispartof: location:England status: published

BackgroundThere is a need for a validated simple Dutch paediatric activity scale. The purpose was to translate and transculturally validate the Dutch Hospital for Special Surgery Paediatric Functional Activity Brief Scale (HSS Pedi-FABS) questionnaire in healthy children and adolescents.MethodsThe original HSS Pedi-FABS was translated forward and backward and was transculturally adapted after performing a pilot study among children and professionals. The final version of the Dutch HSS Pedi-FABS was validated in healthy children and adolescents aged 10 to 18 years old. Children who had any condition or injury limiting their normal physical activity were excluded. The interval between the first questionnaire T0 (HSS Pedi-FABS, Physical Activity Questionnaire for children or adolescents (PAQ-C/A) and Tegner activity scale) and the second questionnaire T1 (HSS Pedi-FABS) was 2 weeks. Construct validity, interpretability and reliability were evaluated. Content validity was evaluated through cognitive interviews among a smaller group of children and through a questionnaire among professionals.ResultsTo evaluate content validity, 9 children and adolescents were interviewed, and 30 professionals were consulted. Content validity among professionals showed a relevance of less than 85% for most items on construct. However, content validity among children was good with a 92% score for item relevance. Readability was scored at a reading level of 11- to 12-year-olds. The validation group consisted of 110 healthy children and adolescents (mean age of 13.9 years ±2.6). Construct validity was considered good as 8 out of 10 hypotheses were confirmed. The Dutch HSS Pedi-FABS showed no floor or ceiling effect. Analysis of the internal consistency in the validation group resulted in a Cronbach’s alpha of 0.82. Test-retest reliability was evaluated among 69 children and adolescents and revealed an Intraclass Correlation Coefficient (ICC) of 0.76.ConclusionThe Dutch HSS Pedi-FABS showed good psychometric properties in a healthy Dutch paediatric and adolescent population. Limitations of the current Dutch HSS Pedi-FABS are content validity on construct of items reported by professionals.

Background and purpose — The preferred treatment of an acute prosthetic joint infection (PJI) is debridement, antibiotics, irrigation and retention of the prosthesis (DAIR). The antibiotic treatment consists of an empirical and targeted phase. In the empirical phase, intravenous antibiotics are started after surgery before micro-organisms are determined in microbiological cultures. Which empirical antibiotic is used differs between hospitals, partly reflecting geographic differences in susceptibility spectrums. We investigated whether flucloxacillin should remain the antibiotic of choice in our hospital for empiric treatment of acute PJI with DAIR. Patients and methods — We retrospectively analyzed 91 patients treated for PJI with DAIR between 2012 and 2016. The susceptibility of micro-organisms was determined in multiple cultures of periprosthetic tissue and synovial fluid for 3 antibiotics: amoxicillin/clavulanic acid, cefazolin, and flucloxacillin. Results — Positive microbiological cultures from 68 patients were analyzed. Staphylococcus aureus was the predominant pathogen, cultured in half of the patients. In one-third of patients more than 1 micro-organism was found. On a patient level, the data showed that 65% were responsive to flucloxacillin, 76% to amoxicillin/clavulanic acid, and 79% to cefazolin. Interpretation — Flucloxacillin appeared to be a suboptimal choice in our patient population treated with DAIR. We therefore changed our practice to cefazolin as the preferred antibiotic in the empirical treatment of acute PJI with DAIR.

Unfulfilled preoperative expectations have a strong influence on the outcome after total knee arthroplasty (TKA). More insight into determinants of the level of expectations is useful in identifying patients at risk for having expectations of the treatment result that are too high or too low. This information can be used in optimizing preoperative expectation management. The aim of the current study was to analyze to what extent preoperative outcome expectations of TKA patients are affected by psychological factors, demographic factors, pain, physical function, and general health status. We performed a cross-sectional analysis of 204 patients with symptomatic and radiographic knee osteoarthritis (OA), scheduled for primary TKA. Outcome expectations were measured using the hospital for special surgery knee replacement expectations survey. Independent variables included were age, sex, body mass index, and patient-reported outcome measures for pain, physical function, quality of life, anxiety, depression, catastrophizing, optimism, and pessimism. Multiple linear regression analyses were used to evaluate associations between these variables and preoperative outcome expectations. Female sex, higher age, higher depression score, and duration of complaints > 50 months showed to be significant predictors of lower expectations for the treatment outcome after TKA. Baseline pain and function scores were not related to the level of preoperative expectations. The present study aids in identifying patients at risk for having either too high or too low expectations. This knowledge can be utilized in individualized expectation management interventions.

Purpose: The aim of this systematic review was to present an evidence-based overview of psychometric properties of patient-reported outcome measures (PROMs) for children with knee ligament injury. Methods: A systematic search of literature was performed in PubMed, EMBASE and Cochrane databases. The inclusion criteria were diagnostic studies evaluating psychometric properties (validity, reliability, responsiveness) and comprehensibility of PROMs as well as studies including children (age

Aims Meeting preoperative expectations is known to be of major influence on postoperative satisfaction after total knee arthroplasty (TKA). Improved management of expectation, resulting in more realistic expectations can potentially lead to higher postoperative satisfaction. The objective of this study was to assess the effect of an additional preoperative education module, addressing realistic expectations for long-term functional recovery, on postoperative satisfaction and expectation fulfilment. Methods In total, 204 primary TKA patients with osteoarthritis were enrolled in this randomized controlled trial (RCT). Patients were allocated to either usual preoperative education (control group) or usual education plus an additional module on realistic expectations (intervention group). Primary outcome was being very satisfied (numerical rating scale for satisfaction ≥ 8) with the treatment result at 12 months' follow-up. Other outcomes were change in preoperative expectations and postoperative expectation fulfilment. Results A total of 187 patients (91.7%) were available for analysis at follow-up. In the intention-to-treat analysis, 58.5% (55/94) of patients were very satisfied with the treatment result in the control group, and 69.9% (65/93) of patients in the intervention group (adjusted odds ratio (AOR) 1.72, 95% confidence interval (CI) 0.90 to 3.29). A per-protocol analysis for patients who attended the education session (92.0%, n = 172) showed that 56.9% (49/86) of patients were very satisfied in the control group and 74.4% (61/86) in the intervention group (AOR 2.44, 95% CI 1.21 to 4.91). After preoperative education, the expectation scores in the intervention group were significantly lower (mean difference -6.9 (95% CI -10.2 to -3.6)) and did not alter in the control group (mean difference 0.5 (95% CI -2.9 to 3.9)). Overall, fulfilment of expectations at 12 months was significantly higher in the intervention group (mean difference 11.4% (95% CI 2.3 to 20.5)). Conclusion Improved preoperative patient education can modify patient expectations, resulting in higher postoperative fulfilment of expectation and higher satisfaction in the group that attended the preoperative education. This is the first RCT to confirm the potential of improved expectation management on satisfaction after TKA. Cite this article: Bone Joint J 2021;103-B(4):619–626.

Meeting preoperative expectations is known to be of major influence on postoperative satisfaction after total knee arthroplasty (TKA). Improved management of expectation, resulting in more realistic expectations can potentially lead to higher postoperative satisfaction. The objective of this study was to assess the effect of an additional preoperative education module, addressing realistic expectations for long-term functional recovery, on postoperative satisfaction and expectation fulfilment.In total, 204 primary TKA patients with osteoarthritis were enrolled in this randomized controlled trial (RCT). Patients were allocated to either usual preoperative education (control group) or usual education plus an additional module on realistic expectations (intervention group). Primary outcome was being very satisfied (numerical rating scale for satisfaction ≥ 8) with the treatment result at 12 months' follow-up. Other outcomes were change in preoperative expectations and postoperative expectation fulfilment.A total of 187 patients (91.7%) were available for analysis at follow-up. In the intention-to-treat analysis, 58.5% (55/94) of patients were very satisfied with the treatment result in the control group, and 69.9% (65/93) of patients in the intervention group (adjusted odds ratio (AOR) 1.72, 95% confidence interval (CI) 0.90 to 3.29). A per-protocol analysis for patients who attended the education session (92.0%, n = 172) showed that 56.9% (49/86) of patients were very satisfied in the control group and 74.4% (61/86) in the intervention group (AOR 2.44, 95% CI 1.21 to 4.91). After preoperative education, the expectation scores in the intervention group were significantly lower (mean difference -6.9 (95% CI -10.2 to -3.6)) and did not alter in the control group (mean difference 0.5 (95% CI -2.9 to 3.9)). Overall, fulfilment of expectations at 12 months was significantly higher in the intervention group (mean difference 11.4% (95% CI 2.3 to 20.5)).Improved preoperative patient education can modify patient expectations, resulting in higher postoperative fulfilment of expectation and higher satisfaction in the group that attended the preoperative education. This is the first RCT to confirm the potential of improved expectation management on satisfaction after TKA. Cite this article

BACKGROUND: Understanding the kinematic characteristics of relapse clubfoot compared to successfully treated clubfoot could aid early identification of a relapse and improve treatment planning. The usage of a multi segment foot model is essential in order to grasp the full complexity of the multi-planar and multi-joint deformity of the clubfoot. RESEARCH QUESTION: The purpose of this study was to identify differences in foot kinematics, using a multi-segment foot model, during gait between patients with Ponseti treated clubfoot with and without a relapse and age-matched healthy controls. METHODS: A cross-sectional study was carried out including 11 patients with relapse clubfoot, 11 patients with clubfoot and 15 controls. Gait analysis was performed using an extended Helen Hayes model combined with the Oxford Foot Model. Statistical analysis included statistical parametric mapping and discrete analysis of kinematic gait parameters of the pelvis, hip, knee, ankle, hindfoot and forefoot in the sagittal, frontal and transversal plane. RESULTS: The relapse group showed significantly increased forefoot adduction in relation with the hindfoot and the tibia. Furthermore, this group showed increased forefoot supination in relation with the tibia during stance, whereas during swing increased forefoot supination in relation with the hindfoot was found in patients with relapse clubfoot compared with non-relapse clubfoot. SIGNIFICANCE: Forefoot adduction and forefoot supination could be kinematic indicators of relapse clubfoot, which might be useful in early identification of a relapse clubfoot. Subsequently, this could aid the optimization of clinical decision making and treatment planning for children with clubfoot. ispartof: GAIT & POSTURE vol:90 pages:415-421 ispartof: location:England status: published

— A delegation of 6 pediatric orthopedic surgeons from the Dutch Orthopedic Association (NOV) and 2 members of the board of the Dutch Parents’ Association for children with clubfoot created the guideline "The diagnosis and treatment of primary idiopathic clubfeet" between April 2011 and February 2014. The development of the guideline was supported by a professional methodologist from the Dutch Knowledge Institute of Medical Specialists. This evidence-based guideline process was new and unique, in the sense that the process was initiated by a parents’ association. This is the first official guideline in pediatric orthopedics in the Netherlands, and to our knowledge it is also the first evidence-based guideline on clubfoot worldwide. The guideline was developed in accordance with the criteria of the international AGREE instrument (AGREE II: Appraisal of Guidelines for Research and Evaluation II). The scientific literature was searched and systematically analyzed. In the second phase, conclusions and recommendations in the literature were formulated according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. Recommendations were developed considering the balance of benefits and harms, the type and quality of evidence, the values and preferences of the people involved, and the costs. The guideline is a solid foundation for standardization of clubfoot treatment in the Netherlands, with a clear recommendation of the Ponseti method as the optimal method of primary clubfoot treatment. We believe that the format used in the current guideline sets a unique example for guideline development in pediatric orthopedics that may be used worldwide. Our format ensured optimal collaboration between medical specialists and parents, and resulted in an important change in clubfoot care in the Netherlands, to the benefit of medical professionals as well as parents and patients. In this way, it is possible to improve professional collaboration between medical specialists and parents, resulting in an important change in clubfoot care in the Netherlands that will benefit medical professionals, parents, and patients. The guideline was published online, and is freely available from the Dutch Guideline Database (www.richtlijnendatabase.nl).

PURPOSE: The Osteoarthritis Research Society International has identified a core set of performance-based tests of physical function for use in people with knee osteoarthritis (OA). The core set consists of the 30-second chair stand test (30-s CST), 4 × 10 m fast-paced walk test (40 m FPWT) and a stair climb test. The aim of this study was to evaluate the reliability, validity and responsiveness of these performance-based measures to assess the ability to measure physical function in knee OA patients.METHODS: A prospective cohort study of 85 knee OA patients indicated for total knee arthroplasty (TKA) was performed. Construct validity and responsiveness were assessed by testing of predefined hypotheses. A subgroup (n = 30) underwent test-retest measurements for reliability analysis. The Oxford Knee Score, Knee injury and Osteoarthritis Outcome Score-Physical Function Short Form, pain during activity score and knee extensor strength were used as comparator instruments. Measurements were obtained at baseline and 12 months after TKA.RESULTS: Appropriate test-retest reliability was found for all three tests. Intraclass correlation coefficient (ICC) for the 30-s CST was 0.90 (95% CI 0.68; 0.96), 40 m FPWT 0.93 (0.85; 0.96) and for the 10-step stair climb test (10-step SCT) 0.94 (0.89; 0.97). Adequate construct validity could not be confirmed for the three tests. For the 30-s CST, 42% of the predefined hypotheses were confirmed; for the 40 m FPWT, 27% and for the 10-step SCT 36% were confirmed. The 40 m FPWT was found to be responsive with 75% of predefined hypothesis confirmed, whereas the responsiveness for the other tests could not be confirmed. For the 30 s CST and 10-step SCT, only 50% of hypotheses were confirmed.CONCLUSIONS: The three performance-based tests had good reliability, but poor construct validity and responsiveness in the assessment of function for the domains sit-to-stand movement, walking short distances and stair negotiation. The findings of the present study do not justify their use for clinical practice.LEVEL OF EVIDENCE: Level 1. Diagnostic study.

BACKGROUND: The Pedi International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) child are validated questionnaires for children with knee disorders. The aim of this study was to translate these questionnaires in Dutch and to recommend which questionnaires should - based on their psychometric properties - be used in clinical practice.METHODS: The English Pedi-IKDC and KOOS-Child were translated by the forward-backward procedure. Subsequently, content validity of the Pedi-IKDC and KOOS-Child was evaluated by both patients (n = 18) and experts (n = 18). To evaluate construct validity and interpretability participants with knee disorders (n = 100) completed the Numeric Rating Scale Pain, Lysholm Knee Scoring Scale, EuroQol-5 Dimension, Pedi-IKDC and KOOS-Child at baseline. Participants completed the anchor question, Pedi-IKDC and KOOS-child two weeks (n = 54) and one year (n = 71) after baseline, for evaluating the test-retest reliability and responsiveness. Psychometric properties were interpreted following the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) criteria.RESULTS: The Pedi-IKDC showed adequate test-retest reliability (intraclass correlation coefficient (ICC) 0.9; standard error of measurement (SEM) 8.6; smallest detectable change (SDC) 23.8), adequate content validity (> 75% relevant), adequate construct validity (75% confirmed hypotheses), low floor or ceiling effects (scores between 5 and 95) and adequate responsiveness (> 75% confirmed hypotheses). The KOOS-Child showed an adequate test-retest reliability (ICC 0.8-0.9; SEM 8.9-16.9; SDC 24.7-46.9), adequate content validity (> 75% relevant, except KOOS-Child subscale ADL), adequate construct validity (75% confirmed hypotheses), low floor and ceiling effects (scores between 5 and 95, except KOOS-Child subscale activities of daily living and Sport/play) and moderate responsiveness (40% confirmed hypotheses).CONCLUSIONS: The Pedi IKDC showed better psychometric properties than the KOOS-Child and should therefore be used in children with knee disorders.

Clinical and radiological related outcomes have been reported for Chevron osteotomy as correction for mild to moderate hallux valgus, but only for relatively small patient series. Moreover, evaluation of the patient's point of view has mostly been conducted by means of more physician-based outcome measures. The goal of this study was to evaluate the effect of the Chevron osteotomy for hallux valgus on patients' daily lives using the Foot and Ankle Outcome Score (FAOS) as a validated and a hallux valgus specific patient reported outcome measure (PROM). Secondary outcome measures were radiological correction, complication rate, and re-operations. All 438 Chevron procedures (336 patients), at two surgical hospital sites in the period between January 2010 and October 2014, were retrospectively evaluated with a follow-up of at least 6 months. Patients were invited to fill in a cross-sectional online FAOS. For the FAOS, a total response of 60% was achieved. The FAOS ranged between 71 and 88 with a follow-up of on average 36 months. Patients with an undercorrection of their hallux valgus (11.6% of the procedures) scored significantly lower on three subscales of the FAOS (range between 61 and 77 versus 72-84). Patients who had a reoperation (12.6% of the procedures) also scored significantly lower on four subscales: 58-100 versus 73-89. Postoperative radiological measurements improved significantly with a mean difference of 6.1 (5.9; 6.4) degrees for the intermetatarsal angle and 13.7 (13.0; 14.5) degrees for the hallux valgus angle. In this large study cohort, Chevron osteotomy for hallux valgus offers good PROM scores on FAOS. These scores were significantly lower in patients with radiological undercorrection or with a reoperation. Results of the FAOS appear to modulate with physician based outcomes and therapeutic incidents. Improvement of outcome may therefore well be possible by increased attention on these surgical details.

Background Clubfeet are commonly treated using the Ponseti method. This method involves weekly manipulation and casting which gradually corrects the position of the foot. However, the reasons for following a weekly interval are not clear. Question / Purpose The aim is to investigate the influence of the cast change interval on treatment outcomes in the Ponseti method. Methods We performed a systematic review of comparative studies in which the cast change interval was varied. Scientific databases were searched for relevant publications, screened for eligibility and assessed for a risk of bias. A 'best evidence' synthesis tool was used to synthesize the results of the included studies and draw conclusions from relevant clinical outcomes. Results Nine papers matched the inclusion criteria, which provided data of 587 subjects who had a total of 870 clubfeet. There is strong evidence for a positive relation between cast change interval and treatment duration. However, there is no evidence for any relation between the cast change interval and the required number of casts, tenotomy rate, required surgery or failure rate. Conclusions Accelerated versions are as effective and safe as the traditional Ponseti method. However, more research is needed to assess the long-term results and to identify an optimal cast change interval.

BACKGROUND: Currently, the Ponseti method is the gold standard for treatment of clubfeet. For long-term functional evaluation of this method, gait analysis can be performed. Previous studies have assessed gait differences between Ponseti treated clubfeet and healthy controls. RESEARCH QUESTION/PURPOSE: The aims of this systematic review were to compare the gait kinetics of Ponseti treated clubfeet with healthy controls and to compare the gait kinetics between clubfoot patients treated with the Ponseti method or surgically. METHODS: A systematic search was performed in Embase, Medline Ovid, Web of Science, Scopus, Cochrane, Cinahl ebsco, and Google scholar, for studies reporting on gait kinetics in children with clubfeet treated with the Ponseti method. Studies were excluded if they only used EMG or pedobarography. Data were extracted and a risk of bias was assessed. Meta-analyses and qualitative analyses were performed. RESULTS: Nine studies were included, of which five were included in the meta-analyses. The meta-analyses showed that ankle plantarflexor moment (95% CI -0.25 to -0.19) and ankle power (95% CI -0.89 to -0.60, were significantly lower in the Ponseti treated clubfeet compared to the healthy controls. No significant difference was found in ankle dorsiflexor and plantarflexor moment, and ankle power between clubfeet treated with surgery compared to the Ponseti method. SIGNIFICANCE: Differences in gait kinetics are present when comparing Ponseti treated clubfeet with healthy controls. However, there is no significant difference between surgically and Ponseti treated clubfeet. These results give more insight in the possibilities of improving the gait pattern of patients treated for clubfeet. ispartof: GAIT & POSTURE vol:66 pages:94-100 ispartof: location:England status: published

Auditory information plays an important role in fine motor control such as speech and musical performance. The purpose of this study was to assess expertise-dependent differences in the role of temporal information of auditory feedback in the production of sequential movements. Differences in motor responses to the transient delay of tone production during musical performance between expert pianists and non-musicians were evaluated. Compared to expert pianists, non-musicians showed more pronounced movement disruptions following the delayed auditory feedback. For example, in response to a perturbation the inter-keystroke interval was prolonged and the key-press was longer in non-musicians, while the expert pianist marginally shortened both measures. These distinct differences between groups suggest that extensive musical training influences feedback control in sequential finger movements. Furthermore, there was a significant positive correlation between the age at which the expert pianists commenced their musical training and the amount of disruption. Overall, these findings suggest that expert pianists have a higher level of robustness against perturbations and depend less on auditory feedback during the performance of sequential movements.

The current study investigated the human ability to synchronize movements with event sequences containing continuous tempo changes. This capacity is evident, for example, in ensemble musicians who maintain precise interpersonal coordination while modulating the performance tempo for expressive purposes. Here we tested an ADaptation and Anticipation Model (ADAM) that was developed to account for such behavior by combining error correction processes (adaptation) with a predictive temporal extrapolation process (anticipation). While previous computational models of synchronization incorporate error correction, they do not account for prediction during tempo-changing behavior. The fit between behavioral data and computer simulations based on four versions of ADAM was assessed. These versions included a model with adaptation only, one in which adaptation and anticipation act in combination (error correction is applied on the basis of predicted tempo changes), and two models in which adaptation and anticipation were linked in a joint module that corrects for predicted discrepancies between the outcomes of adaptive and anticipatory processes. The behavioral experiment required participants to tap their finger in time with three auditory pacing sequences containing tempo changes that differed in the rate of change and the number of turning points. Behavioral results indicated that sensorimotor synchronization accuracy and precision, while generally high, decreased with increases in the rate of tempo change and number of turning points. Simulations and model-based parameter estimates showed that adaptation mechanisms alone could not fully explain the observed precision of sensorimotor synchronization. Including anticipation in the model increased the precision of simulated sensorimotor synchronization and improved the fit of model to behavioral data, especially when adaptation and anticipation mechanisms were linked via a joint module based on the notion of joint internal models. Overall results suggest that adaptation and anticipation mechanisms both play an important role during sensorimotor synchronization with tempo-changing sequences. This article is part of a Special Issue entitled SI: Prediction and Attention.

The problem at the heart of motor control is how the myriad units of the neuromotor system are coordinated to perform goal-directed movements. Although for long these numerous degrees of freedom (DOFs) were considered redundant, recent views emphasize more that the DOFs should be considered abundant, allowing flexible performance. We studied how variability in arm joints was employed to stabilize the displaced end-effector in tool use to examine how the neuromotor system flexibly exploits DOFs in the upper extremity. Participants made pointing movements with the index finger and with the index finger extended by rods of 10, 20, and 30 cm. Using the uncontrolled manifold (UCM) method, the total joint angle variance was decomposed into two parts, the joint angle variance that did not affect the position of the end-effector (V (UCM)) and the variance that results in a deviation of the position of the end-effector from its mean (V (ORT)). Analyses showed that some angles depended on length of the rod in use. For all rod lengths, V (UCM) was larger than V (ORT), and this did not differ over rod lengths, demonstrating that the arm was organized into a synergy. Finally, the variation in the joint angles in the arm as well as the degree of co-variation between these angles did not differ for the rod's tip and the hand. We concluded that synergies are formed in the arm during reaching with an extended end-effector and those synergies stabilize different parts of the arm+rod system equally.