Reliability of Two Recently Developed Procedures Assessing Biological Maturity by Ultrasound Imaging-A Pilot Study.

During puberty, the biological maturity of children of the same chronological age differs. To generate equal opportunities for talent selection in youth sports, the athlete's biological maturity should be considered. This is often assessed with a left hand and wrist radiography. Alternatively, ultrasound (US) could be advantageous, especially by avoiding ionizing radiation. This pilot study aimed to assess intrarater and interrater reliability of an experienced and a non-experienced examiner in an US-based examination of the knee in 20 healthy females (10-17 years). Epiphyseal closure at five anatomical landmarks was staged (stages 1-3) and its interrater and intrarater reliabilities were analyzed using Cohen's kappa (k). Interrater reliability of the calculation of the ossification ratio (OssR) was analyzed using the Bland-Altman method and intraclass correlation coefficients (ICCs). Interrater reliability for the stages was almost perfect for four landmarks. Interrater reliability ranged from k = 0.69 to k = 0.90. Intrarater reliability for the stages was almost perfect for four landmarks. Intrarater reliability ranged from k = 0.70 to k = 1.0. For the OssR, ICC was 0.930 and a minimal detectable change of 0.030 was determined. To conclude, experienced and non-experienced examiners can reliably assign individuals to different ossification stages and calculate an OssR using US-based imaging of the knee.

Test-retest reliability and concurrent validity assessment of a novel high-frequency sensor device for anterior tibial translation measurement in loaded and unloaded condition: an exploratory cross-sectional study.

BACKGROUND: Magnetic resonance imaging (MRI) and manual tests remain the standard for diagnosing anterior cruciate ligament (ACL) rupture. Furthermore, the passive knee displacement, also described as anterior tibial translation (ATT), is used in order to make decisions about surgery or to assess rehabilitation outcomes. Unfortunately, these manual tests are limited to passive situations, and their application to assess knee stability in loaded, weight-bearing positions are missing. Therefore, a new device with high-performance sensors and a new sensor setting was developed. The aim of this exploratory cross-sectional study was to assess the test-retest reliability of this new device in a first step and the concurrent validity in a second step. METHODS: A total of 20 healthy volunteers were measured. Measurement consistency of the new device was assessed on the basis of reliability during Lachman test setting and in loaded position by artificial knee perturbation in a test-retest procedure. In a second step, the concurrent validity was evaluated with the Lachmeter® as a reference instrument. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), the minimal detectable change (MDC) and Bland-Altman analysis were evaluated to assess the quality criteria. RESULTS: The measurements with the new device during the Lachman test provided a mean ATT of 5.46±2.22mm. The SEM ranged from 0.60 to 0.69mm resulting in an MDC between 1.67 and 1.93mm for the new device. In the loaded test situation, the mean ATT was 2.11±1.20mm, with test-retest reliability also showing good correlation (r>0.83). The comparison of the two measurement methods with an ICC of (r>0.89) showed good correlation, which also underlines the reasonable agreement of the Bland-Altman analysis. CONCLUSIONS: The evaluation of the test-retest reliability of the new device during the knee stability testing in passive situation as well as in a functional, loaded situation presented good reliability. In addition, the new device demonstrated good agreement with the reference device and therefore good validity. Furthermore, the quality criteria demonstrated the ability of the new device to detect the cut-off value (3-5mm) described in the literature for the diagnosis of ACL-deficient knees, which underlines the clinical relevance of this new device as a reliable and valid tool.

Conventional video recordings dependably quantify whole-body lifting strategy using the Stoop-Squat-Index: A methods comparison against motion capture and a reliability study.

Whole-body lifting strategies could be derived from conventional video recordings using the Stoop-Squat-Index, which quantifies the ratio between trunk forward lean and lower extremity joint flexion from 0 (full squat) to 100 (full stoop). The purpose of this study was to compare Stoop-Squat-Indices derived from conventional video recordings to those from a three-dimensional marker-based motion capture system and to evaluate interrater and intrarater reliability of the video-based approach. Thirty healthy participants lifted a 5-kg box under different conditions (freestyle, squat, stoop). Kinematic data were recorded using a Vicon motion capture system (serving as reference standard) and an iPad camera. Stoop-Squat-Indices over the entire lifting cycle were derived separately from both approaches. Agreement was assessed using mean differences (video minus motion capture) and limits of agreement. Reliability was investigated by calculating intraclass correlation coefficients (ICC) and minimal detectable changes (MDC) over the course of the lifting cycle. Systematic errors were identified with Statistical Parametric Mapping-based T-tests. Systematic errors between the video-based and the motion capture-based approach were observed among all conditions. Mean differences in Stoop-Squat-Indices over the lifting cycle ranged from -6.9 to 3.2 (freestyle), from -1.8 to 5.3 (squat) and from -2.8 to -1.1 (stoop). Limits of agreement were lower when the box was close to the floor, and higher towards upright standing. Reliability of the video-based approach was excellent for most of the lifting cycle, with ICC above 0.995 and MDC below 3.5. These findings support using a video-based assessment of Stoop-Squat-Indices to quantify whole-body lifting strategy in field.

Ultrasound Imaging-Based Methods for Assessing Biological Maturity during Adolescence and Possible Application in Youth Sport: A Scoping Review.

Bone maturity is an indicator for estimating the biological maturity of an individual. During adolescence, individuals show heterogeneous growth rates, and thus, differences in biological maturity should be considered in talent identification and development. Radiography of the left hand and wrist is considered the gold standard of biological maturity estimation. The use of ultrasound imaging (US) may be advantageous; however, its validity and reliability are under discussion. The aims of this scoping review are (1) to summarize the different methods for estimating biological maturity by US imaging in adolescents, (2) to obtain an overview of the level of validity and reliability of the methods, and (3) to point out the practicability and usefulness of ultrasound imaging in the field of youth sports. The search included articles published up to November 2022. The inclusion criteria stipulated that participants had to fall within the age range of 8 to 23 years and be free of bone disease and fractures in the region of interest. Nine body regions were investigated, while the hand and wrist were most commonly analyzed. US assessment methods were usually based on the estimation of a bone maturity stage, rather than a decimal bone age. Furthermore, 70% of the assessments were evaluated as applicable, 10% expressed restraint about implementation, and 20% were evaluated as not applicable. When tested, inter- and intra-rater reliability was high to excellent. Despite the absence of ionization, low costs, fast assessment, and accessibility, none of the US assessments could be referred to as a gold standard. If further development succeeds, its application has the potential to incorporate biological age into selection processes. This would allow for more equal opportunities in talent selection and thus make talent development fairer and more efficient.

Less in-toeing after femoral derotation osteotomy in adult patients with increased femoral version and posterior hip impingement compared to patients with femoral retroversion.

In-toeing of the foot was associated with high femoral version (FV), while Out-toeing was associated with femoral-retroversion. Therefore, we report on (i) foot-progression-angle (FPA), (ii) prevalence of In-toeing and Out-toeing, and (iii) clinical outcome of patients treated with femoral-derotation-osteotomy (FDO). We performed a retrospective analysis involving 20 patients (20 hips) treated with unilateral FDO (2017-18). Of them, 14 patients had increased FV, 6 patients had femoral-retroversion. Follow-up time was mean 1 ± 1 years. All patients had minimal 1-year follow-up and the mean age was 29 ± 8 years. Patients with increased FV (FV > 35°) presented with positive posterior-impingement-test and mean FV was 49 ± 11° (Murphy method). Six patients with femoral-retroversion (FV < 10°) had positive anterior impingement test and mean FV of 5 ± 4°. Instrumented gait analysis was performed preoperatively and at follow-up using the Gaitrite system to measure FPA and was compared to a control group of 18 healthy asymptomatic volunteers (36 feet, mean age 29 ± 6 years). (i) Mean FPA increased significantly (P = 0.006) from preoperative 1.3 ± 7° to 4.5 ± 6° at follow-up for patients with increased FV and was not significantly different compared to the control group (4.0 ± 4.5°). (ii) In-toeing decreased from preoperatively (five patients) to follow-up (two patients) for patients with increased FV. Out-toeing decreased from preoperatively (two patients) to follow-up (no patient) for patients with femoral-retroversion. (iii) Subjective-hip-value of all patients increased significantly (P < 0.001) from preoperative 21 to 78 points at follow-up. WOMAC was 12 ± 8 points at follow-up. Patients with increased FV that underwent FDO walked with less In-toeing. FDO has the potential to reduce In-toeing and Out-toeing and to improve subjective satisfaction at follow-up.

Spatial distribution of erector spinae activity is related to task-specific pain-related fear during a repetitive object lifting task.

Fear-avoidance beliefs, particularly the fear of lifting with a flexed spine, are associated with reduced spinal motion during object lifting. Low back pain patients thereby also showed potentially clinically relevant changes in the spatial distribution of back muscle activity, but it remains unknown whether such associations are also present in pain-free individuals. This cross-sectional observational study investigated the relationship between fear-avoidance beliefs and the spatial distribution of lumbar paraspinal muscle activity in pain-free individuals during a repetitive lifting task. Thirty participants completed two pain-related fear questionnaires and performed 25 repetitions of lifting a 5 kg-box from a lower to an upper shelf and back, while multi-channel electromyographic signals were recorded bilaterally from the lumbar erector spinae muscles. Changes in spatial distribution were defined as the differences in vertical position of the weighted centroids of muscle activity (centroid shift) between the first and last few repetitions. Linear regression analyses were performed to examine the relationships between centroid shift and fear-avoidance belief scores. Fear of lifting an object with a flexed spine was negatively associated with erector spinae activity centroid shift (R2 adj. = 0.1832; p = 0.045), which might be an expression of behavioral alterations to prevent the back from possible harm.

Minimal Out-Toeing and Good Hip Scores of Severe SCFE Patients Treated With Modified Dunn Procedure and Contralateral Prophylactic Pinning at Minimal 5-year Follow up.

BACKGROUND: Slipped capital femoral epiphyses (SCFE) is associated with out-toeing of the foot and external rotation gait. But it is unknown if SCFE patients treated with the modified Dunn procedure have out-toeing at follow up.Therefore, we used instrumented gait analysis and questioned (1) do severe SCFE patients treated with a modified Dunn procedure have symmetrical foot progression angle (FPA) compared with contralateral side and compared with asymptomatic volunteers (2) what is the prevalence of out-toeing gait and what are the outcome socres at follow up. METHODS: Gait analysis of 22 patients (22 hips) treated with an unilateral modified Dunn procedure for severe SCFE (slip angle >60 degrees, 2002 to 2011) was retrospectively evaluated. Of 38 patients with minimal 5-year follow up, 2 hips (4%) had avascular necrosis of the femoral head and were excluded for gait analysis. Twenty-two patients were available for gait analysis at follow up (mean follow up of 9±2 y). Mean age at follow up was 22±3 years. Mean preoperative slip angle was 64±8 degrees (33% unstable slips) and decreased postoperatively (slip angle of 8±4 degrees). Gait analysis was performed with computer-based instrumented walkway system (GAITRite) to measure FPA with embedded pressure sensors. Patients were compared with control group of 18 healthy asymptomatic volunteers (36 feet, mean age 29±6 y). RESULTS: (1) Mean FPA of SCFE patients (3.6±6.4 degrees) at follow up was not significantly different compared with their contralateral side (5.6±5.5 degrees) and compared with FPA of controls (4.0±4.5 degrees). (2) Of the 22 SCFE patients, most of them (19 hips, 86%) had normal FPA (-5 to 15 degrees), 2 patients had in-toeing (FPA<-5 degrees) and 1 had out-toeing (FPA >15 degrees) and was not significantly different compared with control group. (3) Mean modified Harris hip score (mHHS) was 93±11 points, mean Hip Disability and Osteoarthritis Outcome Score (HOOS) score was 91±10 points. Three patients (14%) had mHHS <80 points and walked with normal FPA. The 2 patients with in-toeing and one patient with out-toeing had mHHS >95 points. CONCLUSIONS: Patients with severe SCFE treated with modified Dunn procedure had mostly symmetrical FPA and good hip scores at long term follow up. This is in contrast to previous studies. Although 1 patient had out-toeing and 2 patients had in-toeing at follow up, they had good hip scores. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Effect of finding-oriented manual therapy techniques on muscle activity and postural control in patients with chronic ankle instability - A randomized controlled feasibility study.

INTRODUCTION: Previous studies have analyzed the effects of manual therapy techniques (MTT) in patients with chronic ankle instability (CAI). Clinicians treat patients according the finding-oriented MTT approach. This approach is seldom pursued in research. The purpose of this study was to evaluate the feasibility and efficacy of finding-oriented MTT applications in patients with CAI. METHOD: In this randomized controlled, blinded assessor crossover feasibility trial, participants were randomized to receive nine finding-oriented MTT treatments or no treatment during a three-week period, followed by a six-day washout period after which participants were crossed-over. Criteria under evaluation were adherence and attrition rates, safety (adverse events (AEs)) and acceptability and preliminary effects of finding-oriented MTT on muscular activity (measured by surface Electromyography (sEMG)) and on dynamic balance (measured by time to stabilization (TTS) and the modified Star Excursion Balance Test (modified STBT)). RESULTS: Seven women and two men (mean age: 26 ± 6.1 years) with CAI enrolled in this feasibility study. Success criteria showed a high adherence (90%) and low attrition rate (10%). All data could be used for analysis. AEs such as tingling in the foot during a short time frame were reported after four finding-oriented MTT interventions. Preliminary effect sizes showed divergence and few statistically significant results for sEMG. CONCLUSION: The participants were adherent to the finding-oriented MTT intervention. The acceptability of data recording and data analysis was good. In addition, the study protocol should be adapted by adding a 10-min warm up period, a participant familiarization to TTS and modified STBT, and test repetitions.

Between-session reliability of skin marker-derived spinal kinematics during functional activities.

BACKGROUND: Skin marker-based analysis of functional spinal movement is a promising method for quantifying longitudinal effects of treatment interventions in patients with spinal pathologies. However, observed day-to-day changes might not necessarily be due to a treatment intervention, but can result from errors related to soft tissue artifacts, marker placement inaccuracies or biological day-to-day variability. RESEARCH QUESTION: How reliable are skin marker-derived three-dimensional spinal kinematics during functional activities between two separate measurement sessions? METHODS: Twenty healthy adults (11 females/9 males) were invited to a movement analysis laboratory for two visits separated by 7-10 days. At each visit, they performed various functional activities (i.e. sitting, standing, walking, running, chair rising, box lifting and vertical jumping), while marker trajectories were recorded using a skin marker-based 10-camera optical motion capture system and used to calculate sagittal and frontal plane spinal curvature angles as well as transverse plane segmental rotational angles in the lumbar and thoracic regions. Between-session reliability for continuous data and discrete parameters was determined by analyzing systematic errors using one sample T-tests as well as by calculating intraclass correlation coefficients (ICCs) and minimal detectable changes (MDCs). RESULTS AND SIGNIFICANCE: The analysis indicated high relative consistency for sagittal plane curvature angles during all activities, but not for frontal and transverse plane angles during walking and running. MDCs were mostly below 15°, with relative values ranging between 10 % and 750 %. This study provides important information that can serve as a basis for researchers and clinicians aiming at investigating longitudinal effects of treatment interventions on spinal motion behavior in patients with spinal pathologies.

Activation patterns of pelvic floor muscles in women with incontinence while running: a randomized controlled trial.

INTRODUCTION AND HYPOTHESIS: Running is known to cause urinary leakage in women with stress urinary incontinence (SUI). Task-specific fiber-type recruitment while running can be estimated using wavelets. The aim of this study was to compare the effect of a new physiotherapy program including involuntary, reflexive training with a standard physiotherapy program on pelvic floor muscle (PFM) activation patterns and fiber-type recruitment behavior while running. METHODS: In this triple-blinded randomized controlled trial, women with SUI were randomly allocated to the control group (CON), which performed a standard physiotherapy program, or the experimental group (EXP), which received additional involuntary, reflexive training. PFM electromyography (EMG) was recorded during 10 s at three running speeds and analyzed using Morse wavelets. The relative distribution of power (%) over the frequencies from 20 to 200 Hz was extracted and analyzed within six-time intervals of 30 ms. Statistical nonparametric mapping was performed to identify power spectra differences. RESULTS: Thirty-nine (CON) and 38 (EXP) women were included. The power spectra showed no statistically significant group differences. The time intervals from 30 ms before to 30 ms after initial contact showed significantly lower intensities than the intervals from 30 to 150 ms after initial contact in the lowest and higher intensities in the highest frequencies for all running speeds and both groups. CONCLUSIONS: Power spectra shifts toward higher frequency bands in the pre-initial contact phase could indicate a feed-forward anticipation and a muscle tuning for the expected impact of initial contact event in order to maintain continence.

Long-term follow-up after patellar tendon shortening for flexed knee gait in bilateral spastic cerebral palsy.

BACKGROUND: Flexed knee gait is a common gait dysfunction in individuals with bilateral spastic cerebral palsy (BSCP) and is often addressed with single event multilevel surgery (SEMLS). SEMLS has been shown to have positive short-term effects especially on sagittal knee joint kinematics with less knee flexion during stance phase. However, mid- and long-term observations are rare, and results are reported in discrete parameters or summary statistics where temporal aspects are not considered. RESEARCH QUESTION: Does the improved knee joint kinematics after patellar tendon shortening (PTS) as part of SEMLS persist in the long-term in individuals with BSCP? METHODS: Data of instrumented gait analysis of twelve participants (females/males: 5/7, mean age: 15.3 ±â€¯3.4 years) with BSCP treated with PTS as part of SEMLS were retrospectively analyzed. Participants had had follow-up gait analysis 1, 5 and 7 years or more after surgery. Three-dimensional lower extremity kinematics of walking at a self-selected speed were collected using a 12-camera motion capture system and 4 embedded force plates. One-dimensional statistical parametric mapping (SPM) was used for data analysis, permitting time point comparisons of continuous data. RESULTS: Time point comparison revealed no significant differences in the sagittal plane for knee joint kinematics (p > 0.05) over the tree measurement time points. Hip and ankle joint kinematics as well as normalised walking speed remained stable over the observation period. SIGNIFICANCE: This is the first study investigating lower extremity kinematics in patients with BSCP and flexed knee gait after SEMLS with SPM. Results demonstrate that positive effects on sagittal knee joint kinematics of PTS as part of SEMLS persist up to 9 years after surgery and progressivity does not reoccur. Thus, if clinical examination indicates an operation in individuals with BSCP, improved kinematics through SEMLS persist into adulthood. With the relatively new statistical procedure SPM gait can be displayed and analysed in established joint angle curves making them easier to understand (e.g. physiotherapists, movement scientists, physicians).

Walking and running with non-specific chronic low back pain: What about the lumbar lordosis angle?

Non-specific chronic low back pain (NSCLBP) is a major health problem, affecting about one fifth of the population worldwide. To avoid further pain or injury, patients with NSCLBP seem to adopt a stiffer movement pattern during everyday living activities. However, it remains unknown how NSCLBP affects the lumbar lordosis angle (LLA) during repetitive activities such as walking or running. This pilot study therefore aimed at exploring possible NSCLBP-related alterations in LLAs during walking and running by focusing on discrete parameters as well as continuous data. Thirteen patients with NSCLBP and 20 healthy pain-free controls were enrolled and underwent a full-body movement analysis involving various everyday living activities such as standing, walking and running. LLAs were derived from markers placed on the spinous processes of the vertebrae L1-L5 and S1. Possible group differences in discrete (average and range of motion (ROM)) and continuous LLAs were analyzed descriptively using mean differences with confidence intervals ranging from 95% to 75%. Patients with NSCLBP indicated reduced average LLAs during standing, walking and running and a tendency for lower LLA-ROM during walking. Analyses of continuous data indicated the largest group differences occurring around 25% and 70% of the walking and 25% and 75% of the running cycle. Furthermore, patients indicated a reversed movement pattern during running, with increasing instead of a decreasing LLAs after foot strike. This study provides preliminary evidence that NSCLBP might affect LLAs during walking and running. These results can be used as a basis for future large-scale investigations involving hypothesis testing.

Electromyography of pelvic floor muscles with true differential versus faux differential electrode configuration.

INTRODUCTION AND HYPOTHESIS: In pelvic floor muscle (PFM) electromyography (EMG) two different bipolar configurations are applied: "true differential" configuration (TD) measures neuromuscular activity with two ipsilateral electrodes, whereas "faux differential" configuration (FD) has two electrodes placed on each side of the PFMs. The aim of the study was to determine possible differences and the relationship between both configurations. METHODS: A secondary data analysis of 28 continent (CON) and 22 stress urinary incontinent (SUI) women was performed. Surface EMG was measured using a vaginal probe during maximal voluntary (MVC) and fast voluntary (FVC) contractions. TD and FD were explored with amplitude- and time-related EMG parameters, cross-correlation coefficients (R(0)) and statistical parametric mapping (SPM). RESULTS: Of a total of 62 comparisons of EMG parameters of MVC and FVC, only one comparison showed significant differences between the two configurations (CON group, FVC4peak TD versus FD, p = 0.015). R(0) were high in both groups for all MVC and FVC variables (R(0) ≥ 0.989). SPM detected 3 out of 28 comparisons with short (0.124-0.404 s) significant supra-threshold clusters (p < 0.025). CONCLUSIONS: The findings suggest that TD and FD might measure neuromuscular activity almost the same. Very high cross-correlation coefficients and a very limited number of significant results from EMG parameters, as well as SPM, suggest that in the measured sample the choice of TD or FD might remain practically irrelevant. To gain further insight into the scientific and clinical relevance of choosing either of the electrode configurations, the comparisons should be re-evaluated on a sample with more severe incontinence symptoms.

Measuring lumbar back motion during functional activities using a portable strain gauge sensor-based system: A comparative evaluation and reliability study.

Quantifying lumbar back motion during functional activities in real-life environments may contribute to a better understanding of common pathologies such as spinal disorders. The current study therefore aimed at the comparative evaluation of the Epionics SPINE system, a portable device for measuring sagittal lumbar back motion during functional activities. Twenty healthy participants were therefore evaluated with the Epionics SPINE and a Vicon motion capture system in two identical separate research visits. They performed the following activities: standing, sitting, chair rising, box lifting, walking, running and a counter movement jump (CMJ). Lumbar lordosis angles were extracted as continuous values as well as average and range of motion (ROM) parameters. Agreement between the systems was evaluated using Bland-Altman analyses, whereas within- and between-session reliability were assessed using intraclass correlation coefficients (ICC) and minimal detectable changes (MDC). The analysis showed excellent agreement between the systems for chair rising, box lifting and CMJ with a systematic underestimation of lumbar lordosis angles during walking and running. Reliability was moderate to high for all continuous and discrete parameters (ICC ≥ 0.62), except for ROM during running (ICC = 0.29). MDC values were generally below 15°, except for CMJ (peak values up to 20° within and 25° between the sessions). The Epionics SPINE system performed similarly to a Vicon motion capture system for measuring lumbar lordosis angles during functional activities and showed high consistency within and between measurement sessions. These findings can serve researchers and clinicians as a bench mark for future investigations using the system in populations with spinal pathologies.

Pelvic floor muscle activity patterns in women with and without stress urinary incontinence while running.

BACKGROUND: High-impact activities are often related to urine leakage in women, so deeper insight into continence mechanisms of pelvic floor muscles (PFMs) while running is needed. Therefore, simultaneous information about the intensity of PFM muscle activity and fibre recruitment behavior at each time point of the gait cycle can help in understanding PFM activity patterns. OBJECTIVE: We aimed to analyse spectral changes of the pre- and post-initial contact phase during running at 3 different speeds and to compare women with stress urinary continence (SUI) to those without SUI by using a wavelet approach. METHODS: PFM electromyography (EMG) was recorded during 7, 11 and 15km/h treadmill running and analysed with Morse wavelets. The relative distribution of power was extracted during 6 time intervals of 30ms, from 30ms before to 150ms after initial contact. RESULTS: We included 28 women without SUI (mean [SD] age 38.9 [10.3] years) and 21 with SUI (mean age 46.1 [9.9] years). The groups did not differ in power spectra for each time interval. However, we found significantly less EMG intensity in the lower frequency bands but more intensity in the higher frequency bands in the pre-initial contact phase than at post-initial contact. CONCLUSION: Morse wavelets could be used to extract differences between pre- and post-initial contact activation behavior of PFMs during different running speeds as well as spectral changes toward high or low frequencies. This information sheds light on specific differences in involuntary reflexive activation patterns while running. Muscular preparation and adaptation a few milliseconds before initial contact could be helpful.

Prevalence and diagnostic accuracy of in-toeing and out-toeing of the foot for patients with abnormal femoral torsion and femoroacetabular impingement: implications for hip arthroscopy and femoral derotation osteotomy.

AIMS: Abnormal femoral torsion (FT) is increasingly recognized as an additional cause for femoroacetabular impingement (FAI). It is unknown if in-toeing of the foot is a specific diagnostic sign for increased FT in patients with symptomatic FAI. The aims of this study were to determine: 1) the prevalence and diagnostic accuracy of in-toeing to detect increased FT; 2) if foot progression angle (FPA) and tibial torsion (TT) are different among patients with abnormal FT; and 3) if FPA correlates with FT. PATIENTS AND METHODS: A retrospective, institutional review board (IRB)-approved, controlled study of 85 symptomatic patients (148 hips) with FAI or hip dysplasia was performed in the gait laboratory. All patients had a measurement of FT (pelvic CT scan), TT (CT scan), and FPA (optical motion capture system). We allocated all patients to three groups with decreased FT (< 10°, 37 hips), increased FT (> 25°, 61 hips), and normal FT (10° to 25°, 50 hips). Cluster analysis was performed. RESULTS: We found a specificity of 99%, positive predictive value (PPV) of 93%, and sensitivity of 23% for in-toeing (FPA < 0°) to detect increased FT > 25°. Most of the hips with normal or decreased FT had no in-toeing (false-positive rate of 1%). Patients with increased FT had significantly (p < 0.001) more in-toeing than patients with decreased FT. The majority of the patients (77%) with increased FT walk with a normal foot position. The correlation between FPA and FT was significant (r = 0.404, p < 0.001). Five cluster groups were identified. CONCLUSION: In-toeing has a high specificity and high PPV to detect increased FT, but increased FT can be missed because of the low sensitivity and high false-negative rate. These results can be used for diagnosis of abnormal FT in patients with FAI or hip dysplasia undergoing hip arthroscopy or femoral derotation osteotomy. However, most of the patients with increased FT walk with a normal foot position. This can lead to underestimation or misdiagnosis of abnormal FT. We recommend measuring FT with CT/MRI scans in all patients with FAI. Cite this article: Bone Joint J 2019;101-B:1218-1229.

Pelvic floor muscle displacement during jumps in continent and incontinent women: An exploratory study.

INTRODUCTION: The prevalence of stress urinary incontinence during high-impact activities is high. Enhanced comprehension of pelvic floor muscle (PFM) displacement and activity is clinically relevant for the development of specific approaches in rehabilitation. The aim of the study is to investigate and to compare PFM displacement between the continent and incontinent women during jumps. METHODS: A cross-sectional, exploratory design was applied to investigate PFM displacement during drop jumps (DJ) and countermovement jumps (CMJ). PFM displacement was assessed in craniocaudal translation and forward-backward rotation with an electromagnetic tracking system. RESULTS: Twenty-eight continent and 22 incontinent women were included. During the first landing of DJ, a primary caudal, during the second landing of DJ/CMJ a primary cranial translation and during all jump a primary backward rotation was observed. No significant difference between the groups was found. DISCUSSION: PFM displacement during running demonstrated caudal translation/forward rotation before and cranial translation/backward rotation after heel strike. During the second landing of DJ/CMJ a cranial translation/backward rotation and during the first landing of DJ a caudal translation/backward rotation has been observed after ground contact. This may be due to the longer lasting bodyweight force in the first landing of DJ. No eccentric-concentric stretch-shortening cycle could be seen. CONCLUSION: This study indicates that during jumps two opposite reactions of involuntary PFM displacement happen, but no stretch-shortening cycle with an eccentric-concentric contraction could be found. Jumping stimuli inducing involuntary PFM displacement should be used for future investigations to consider a beneficial effect concerning continence.

Pelvic floor muscle activity during fast voluntary contractions in continent and incontinent women.

AIMS: Stress urinary incontinence (SUI) has also been attributed to a lower speed of contraction of the pelvic floor muscles (PFM). Therefore, PFM assessment and training implement fast voluntary contractions (FVC). The purpose of the study was to explore FVC regarding feasibility, on-/offset and rate of activity determination, as well as differences between continent (CON) and stress urinary incontinent (SUI) women. METHODS: Fifty women were included and examined by means of PFM EMG during rest, maximum voluntary contractions (MVC), and five FVC. MVC-peak activity was used to normalize EMG-data. On-/offset of muscle activity was determined as mean of rectified rest activity plus 1 standard deviation. Linear regression was calculated for rate of activity from onset to peak, peak to offset, and within 200 ms after both onset and peak. Peak activity and time variables related to onset, peak, and offset were calculated. RESULTS: On-/offsets were evaluable for 234/222 of 250 FVC by a computer-based algorithm, 16/28 on-/offsets had to be determined manually. There was no significant difference between groups (CON/SUI) regarding FVC peak (92.1/99.3 %MVC), time to peak (514.2/525.6 ms), and increase of activity (182.8/182.1 %MVC/s). The SUI group showed a significantly slower activity decrease (-120.7/-74.4 %MVC/s). CONCLUSIONS: FVC analyses were shown to be feasible. The significant difference observed between the groups did not refer to activity increase but instead to a prolonged relaxation phase in the SUI group. This prompts to reconsider the interpretation of FVC in PFM testing and training.

Cranio-caudal and medio-lateral navicular translation are representative surrogate measures of foot function in asymptomatic adults during walking.

INTRODUCTION: The translation of the navicular bone is thought to be a representative surrogate measure to assess foot pronation and hence foot function; however, it is not known how it is related to multi-segment foot kinematics. METHODS: Cranio-caudal (NCC) and medio-lateral (NML) navicular translation and multi-segment foot kinematics from the Oxford Foot Model (OFM) were simultaneously assessed during the stance phase of walking in 20 healthy adults. Relationships to forefoot to hindfoot (FFtoHF), hindfoot to tibia (HFtoTBA) and global hindfoot (HFL) motion were explored by cross-correlations at zero phase shift. RESULTS: FFtoHF sagittal, transversal and frontal plane angles showed median cross correlations of -0.95, 0.82 and 0.53 with NCC and of 0.78, -0.81 and -0.90 with NML. HFtoTBA transversal and frontal plane angles had correlations of 0.15 and 0.74 with NCC and of -0.38 and -0.83 with NML. The HFL frontal plane angle showed correlations of 0.41 and -0.44 with NCC and NML, respectively. DISCUSSION: The strongest relationships were found between FFtoHF sagittal plane angles and NCC and between FFtoHF frontal plane angles and NML. However, cranio-caudal and medio-lateral navicular translation seem to be reasonable surrogates for the triplanar motion between the fore- and hindfoot. The medial longitudinal arch dropped and bulged medially, while the forefoot dorsiflexed, abducted and everted with respect to the hindfoot and vice-versa. The lower cross-correlation coefficients between the rear foot parameters and NCC/NML indicated no distinct relationships between rearfoot frontal plane and midfoot kinematics. The validity of rearfoot parameters, like Achilles tendon or Calcaneal angle, to assess midfoot function must be therefore questioned. The study could also not confirm a systematic relationship between midfoot kinematics and the internal/external rotation between the hindfoot and the tibia. The measurement of navicular translation is suggested as an alternative to more complex multi-segment foot models to assess foot function.

Walking with an induced unilateral knee extension restriction affects lower but not upper body biomechanics in healthy adults.

BACKGROUND: Unilateral knee flexion contractures (KFC) are frequently seen in orthopedic rehabilitation and often interfere with the normal gait pattern, resulting in passive and/or active secondary deviations. In order to prevent KFC-related complications such as patellofemoral pain or the knee spine syndrome, a comprehensive understanding of such deviations is necessary. RESEARCH QUESTION: How does an artificially induced unilateral KFC affect whole body biomechanics in young healthy adults during gait? METHODS: Twenty-four healthy young adults (females/males: 13/11; mean age: 27.3 ±â€¯3.8 years) were included in this cross-sectional study. Using an 8-camera optical motion capture system and two embedded force plates, three-dimensional lower extremity, pelvis and trunk kinematics as well as lower extremity joint moments were derived during normal walking and walking with unilateral KFCs by means of a lightweight knee brace locked at 30° and 60° of flexion. Data were analyzed using one-dimensional statistical parametric mapping, allowing explorative group comparisons of continuous data rather than pre-defined discrete parameters. RESULTS: On the braced side, increased hip flexion (p < 0.001, 1-100 % of gait cycle [%GC]), knee flexion (p < 0.001, 1-72 and 82-100 %GC) and ankle dorsiflexion angles (p < 0.001, 1-100 %GC) as well as external knee flexion moments (p < 0.001, 1-98 % of stance phase [%StPh]) and decreased ankle dorsiflexion (p < 0.001, 74-94 %StPh), hip flexion and hip adduction moments (p < 0.001, 1-32 %StPh and p < 0.001, 71-92 %StPh, respectively) were observed. The unbraced side showed similar but less pronounced deviations. Pelvis and upper body kinematics were not altered, suggesting that the lower limbs fully compensate for KFCs of less than 30°. SIGNIFICANCE: Asymmetric limb loading and considerable increases in external knee flexion moments might increase the risk for adverse effects of lower extremity joints in the long-term. It seems therefore important to treat KFCs as early as possible and to implement preventive strategies to avoid possible complications.