A comprehensive MRI investigation to identify potential biomarkers of Osgood Schlatter disease in adolescents: A cross sectional study comparing Osgood Schlatter disease with controls

BACKGROUND

Osgood-Schlatter disease (OSD) is the most common knee pain complaint among adolescents playing sports. Despite this, there remains controversy over the pathophysiology and whether specific anatomical characteristics are associated with OSD.

PURPOSE

This study aimed to systematically and comprehensively characterize adolescents with OSD using magnetic resonance imaging (MRI) compared to pain-free controls, including both tissue abnormalities that may be associated with OSD, as well as anatomical characteristics. A secondary objective was to identify potential imaging biomarkers associated with pain.

STUDY DESIGN

Cross-sectional study.

METHODS

Adolescents with OSD and controls were recruited from 2020 to 2022. Following a clinical exam, demographics, pain, sports participation, and Tanner stage were collected. Knee MRI was conducted on the participants' most symptomatic knee (OSD) or the dominant leg (controls).

RESULTS

Sixty-seven adolescents (46 with OSD and 30 controls) were included. 80% of participants with OSD had at least one tissue alteration compared to 54% of controls. Compared to controls, OSD had 36.3 (95%CI 4.5 to 289.7) higher odds of bony oedema at the tibial tuberosity, and 32.7 (95%CI 4.1 to 260.6) and 5.3 (95%CI 0.6 to 46.2) higher odds of bony oedema at the  tibial epiphysis and metaphysis respectively. Participants with OSD also had higher odds of fluid/oedema at the patellar tendon (12.3 95%CI 3.3 to 46.6), and superficial infrapatellar bursitis (7.2).  Participants with OSD had a more proximal tendon attachment (mean tibial attachment portion difference, -0.05, 95% CI: -0.1 to 0.0, p = 0.02), tendon thickness (proximal mean difference, -0.09, 95% CI: -0.4 to 0.2, p = 0.04; distal mean difference, -0.6, 95% CI: -0.9 to -0.2, p = 0.01). Those with bony/tendon oedema had 1.8 points (95% CI: 0.3 to 3.2) higher pain on palpation than those without (t = -2.5, df = 26.6, p = 0.019), but there was no difference between these groups in a functional single leg pain provocation.

CONCLUSION

Adolescents with OSD present with tissue and structural abnormalities on MRI that differed from age-matched controls. The majority had findings in the patellar tendon and bone, which often co-occurred. However, a small proportion of OSD also presents without alterations. It appears these findings may be associated with clinical OSD-related pain on palpation of the tibial tuberosity.

CLINICAL RELEVANCE

Our highlight the pathophysiology on imaging, which has implications for understanding the mechanism and treatment of OSD.

Self-management including exercise, education and activity modification compared to usual care for adolescents with Osgood-Schlatter (the SOGOOD trial): protocol of a randomized controlled superiority trial

BACKGROUND

Osgood-Schlatter is the most frequent growth-related injury affecting about 10% of physically active adolescents. It can cause long-term pain and limitations in sports and physical activity, with potential sequela well into adulthood. The management of Osgood-Schlatter is very heterogeneous. Recent systematic reviews have found low level evidence for surgical intervention and injection therapies, and an absence of studies on conservative management. Recently, a novel self-management approach with exercise, education, and activity modification, demonstrated favorable outcomes for adolescents with patellofemoral pain and Osgood-Schlatter in prospective cohort studies.

AIM

The aim of this trial is to assess the effectiveness of the novel self-management approach compared to usual care in improving self-reported knee-related function in sport (measured using the KOOS-child 'Sport/play' subscale) after a 5-month period.

METHODS

This trial is a pragmatic, assessor-blinded, randomized controlled trial with a two-group parallel arm design, including participants aged 10-16 years diagnosed with Osgood-Schlatter. Participants will receive 3 months of treatment, consisting of either usual care or the self-management approach including exercise, education, and activity modification, followed by 2 months of self-management. Primary endpoint is the KOOS-child 'Sport/play' score at 5 months. This protocol details the planned methods and procedures.

DISCUSSION

The novel approach has already shown promise in previous cohort studies. This trial will potentially provide much-needed level 1 evidence for the effectiveness of the self-management approach, representing a crucial step towards addressing the long-term pain and limitations associated with Osgood-Schlatter.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT05174182. Prospectively registered December 30th 2021. Date of first recruitment: January 3rd 2022. Target sample size: 130 participants.

Does a corticosteroid injection plus exercise or exercise alone add to the effect of patient advice and a heel cup for patients with plantar fasciopathy? A randomised clinical trial

OBJECTIVE

To compare the effectiveness of patient advice plus heel cup alone (PA) versus PA and lower limb exercise (PAX) versus PAX plus corticosteroid injection (PAXI) to improve self-reported pain in patients with plantar fasciopathy.

METHODS

We recruited 180 adults with plantar fasciopathy confirmed by ultrasonography for this prospectively registered three-armed, randomised, single-blinded superiority trial. Patients were randomly allocated to PA (n=62), PA plus self-dosed lower limb heavy-slow resistance training consisting of heel raises (PAX) (n=59), or PAX plus an ultrasound-guided injection of 1 mL triamcinolone 20 mg/mL (PAXI) (n=59). The primary outcome was changed in the pain domain of the Foot Health Status Questionnaire (ranging from 0 'worst' to 100 'best') from baseline to the 12-week follow-up. The minimal important difference in the pain domain is 14.1 points. The outcome was collected at baseline and at 4, 12, 26, and 52 weeks.

RESULTS

The primary analysis found a statistically significant difference between PA and PAXI after 12 weeks favouring PAXI (adjusted mean difference: -9.1 (95% CI -16.8 to -1.3; p=0.023)) and over 52 weeks (adjusted mean difference: -5.2 (95% CI -10.4 to -0.1; p=0.045)). At no follow-up did the mean difference between groups exceed the pre-specified minimal important difference. No statistically significant difference was found between PAX and PAXI or between PA and PAX at any time.

CONCLUSION

No clinically relevant between-group differences were found after 12 weeks. The results indicate that combining a corticosteroid injection with exercise is not superior to exercise or no exercise.

TRIAL REGISTRATION NUMBER

NCT03804008.

Do adolescents with Osgood-Schlatter display nociplastic pain manifestations compared to controls: A cross-sectional study

OBJECTIVES

Osgood-Schlatter disease is an overuse musculoskeletal pain condition. The pain mechanism is considered nociceptive, but no studies have investigated nociplastic manifestations. This study investigated pain sensitivity and inhibition evaluated through exercise-induced hypoalgesia in adolescents with and without Osgood-Schlatter.

DESIGN

Cross-sectional study.

METHODS

Adolescents underwent a baseline assessment comprising clinical history, demographics, sports participation, and pain severity rated (0-10) during a 45-second anterior knee pain provocation test, consisting of an isometric single leg squat. Pressure pain thresholds were assessed bilaterally at the quadriceps, tibialis anterior muscle, and the patella tendon before and after a three-minute wall squat.

RESULTS

Forty-nine adolescents (27 Osgood-Schlatter, 22 controls) were included. There were no differences in the exercise-induced hypoalgesia effect between Osgood-Schlatter and controls. Overall, an exercise-induced hypoalgesia effect was detected at the tendon only in both groups with a 48 kPa (95 % confidence interval 14 to 82) increase in pressure pain thresholds from before to after exercise. Controls had higher pressure pain thresholds at the patellar tendon (mean difference 184 kPa 95 % confidence interval 55 to 313), tibialis anterior (mean difference 139 kPa 95 % confidence interval 24 to 254), and rectus femoris (mean difference 149 kPa 95 % confidence interval 33 to 265). Higher anterior knee pain provocation severity was associated with lower exercise-induced hypoalgesia at the tendon (Pearson correlation = 0.48; p = 0.011) in participants with Osgood-Schlatter.

CONCLUSIONS

Adolescents with Osgood-Schlatter display increased pain sensitivity locally, proximally, and distally but similar endogenous pain modulation compared to healthy controls. Greater Osgood-Schlatter severity appears to be associated with less efficient pain inhibition during the exercise-induced hypoalgesia paradigm.

Quality of life in adolescents with longstanding non-traumatic knee pain: An analysis of 316 adolescents with Patellofemoral Pain and Osgood-Schlatter Disease

OBJECTIVES

To describe the Quality of Life (QoL) among adolescents with Patellofemoral Pain (PFP) and Osgood-Schlatter Disease (OSD) and investigate characteristics associated with QoL.

STUDY DESIGN

Cross-sectional.

PARTICIPANTS

316 adolescents with PFP or OSD.

MAIN OUTCOME MEASURES

QoL subscale of The Knee injury and Osteoarthritis Outcome Score (KOOS) and the EuroQol 5-dimensions (EQ-5D).

RESULTS

The KOOS-QoL was 51 ± 18, and the total index score for the EQ5D was 0.67 ± 0.21. KOOS-QoL subscale showed that 60% reported being aware of their knee problems daily or constantly, 38% reported severe to extreme lack of confidence in their knees, 28% reported severe to extreme difficulty with their knees, and 20% reported severely or totally modifying their lifestyle to avoid potentially damaging activities to their knee. EQ-5D showed that 79% experienced problems with everyday activities, 48% reported mobility problems, 17% felt worried, sad, or unhappy, and 7% reported problems looking after themselves.

CONCLUSIONS

Many adolescents with longstanding non-traumatic knee pain experience low QoL. More than half were aware of their knee problems at least daily, one in three reported a severe lack of confidence in their knee, and one in six felt worried, sad, or unhappy.

Bio-psycho-social characteristics and impact of musculoskeletal pain in one hundred children and adolescents consulting general practice

Background

Eight percent of all child and adolescent general practice consultations are due to musculoskeletal conditions, with pain as the most frequent symptom. Despite the commonality of musculoskeletal pain, limited knowledge exists about care-seeking children and adolescents with musculoskeletal pain.

The purpose of this study was to describe characteristics of children and adolescents consulting their general practitioner with musculoskeletal pain.

Methods

This is a cross-sectional study based on baseline data from the child and adolescent musculoskeletal pain cohort study (ChiBPS), carried out in 17 Danish general practice clinics. Patients aged 8–19 years who had musculoskeletal pain when consulting their general practitioner were recruited. Participants completed a questionnaire on demographics, physical activity, pain impact, psychosocial factors, and expectations of their general practitioner. Descriptive statistics were used to summarize data. Normally distributed continuous data were described using mean and standard deviation while non-normally data were described using median and interquartile range (IQR).

Results

We included 100 participants (54% female, median age 13 [IQR: 12–16.5 years]). Frequent pain sites limiting activity were knee (56%), back (20%), ankle (19%), and neck (13%). Most participants (63%) consulted their general practitioner due to inability to use their body as usual, due to pain. Median pain duration at consultation was 5 months [IQR: 3 weeks-1 year]. More than a third were often/sometimes nervous (34%), worried or anxious (33%), and took pain medication (33%). Pain impeded ability to participate in sport activities at school (79%) and disturbed spare time activities (88%). Pain also made it difficult to concentrate for 58%, and to fall asleep for 38%. Only 38% expected a pain free long-term future.

Conclusion

This study demonstrates the bio-psycho-social impact of musculoskeletal pain in care-seeking children and adolescents. Demographics, pain characteristics, psychosocial characteristics, and physical characteristics should be included in addressing children and adolescents with musculoskeletal pain.

Trial registration

The ChiBPS study was pre-registered before participant recruitment (ClinicalTrials.gov Identifier: NCT03678922) date: 09.20.18.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-022-01628-8.

[Bilateral plantar fasciitis after azithromycin treatment]

Tendinopathy is considered an overuse syndrome which usually results from excessive loading of the tendon during vigorous training activity. There are, however, various causes of this condition other than mechanical causes. This is a case report, in which a 42-year-old male suffered from bilateral plantar fasciitis after treatment with azithromycin for gastroenteritis. Azithromycin-induced tendinitis is a rare side effect, but it is important to know about this and other non-mechanical causes of tendinopathy, and to distinguish them from common mechanical causes in order to optimize treatment.

Large variation in participant eligibility criteria used in plantar heel pain research studies - a systematic review

Introduction

Variable eligibility criteria across studies on plantar heel pain may result in compromising the generalisability of meta-analyses when heterogeneity is not accounted for. We aimed to explore: (i) heterogeneity of participant eligibility criteria in studies that have investigated plantar heel pain, and (ii) associations between key eligibility criteria and the characteristics of the participants included in the study.

Methods

In this systematic review with narrative synthesis, we extracted participant eligibility criteria, and participants’ age, body mass index (BMI), symptom duration and pain level from published studies on plantar heel pain. We performed a content analysis of criteria and aligned overarching criteria to the International Classification of Functioning, Disability and Health (ICF). We pooled studies that used the same thresholds for participant eligibility criteria into sub-groups. We also pooled and reported studies that did not have any eligibility criteria for the quantitative characteristics to use their data for reference values and pooled studies that did not have any eligibility criteria for the characteristics as reference.

Results

Two hundred and fourteen articles were included. The most reported participant eligibility criteria (as aligned to the ICF) related to body structures/function and personal factors. Age, BMI, symptom duration and pain level were used with various ranges and/or thresholds across studies (age was reported in 23 different ways across 97 studies; BMI 7/13; symptom duration 14/100; and pain level 8/31). When eligibility criteria included thresholds close to the reference value of a participant characteristic, characteristics were associated with criteria (e.g., younger participants when an upper age threshold was used).

Conclusion

Participant eligibility criteria in studies on plantar heel pain vary widely; studies differed substantially in their use of quantitative thresholds. Participant characteristics of samples in studies were associated with the criteria used. This study emphasises a need for adjusting for participant heterogeneity in systematic reviews to improve their validity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-022-00573-0.

The influence of exercise on clinical pain and pain mechanisms in patients with subacromial pain syndrome

Background

Few studies have investigated the underlying mechanisms for unilateral subacromial pain syndrome (SAPS). Therefore, this study examined (1) if 8‐weeks of exercise could modulate clinical pain or temporal summation of pain (TSP), conditioned pain modulation (CPM), and exercise‐induced hypoalgesia (EIH) and (2) if any of these parameters could predict the effect of 8‐weeks of exercise in patients with unilateral SAPS.

Methods

Thirty‐seven patients completed a progressive abduction exercise program every other day for 8‐weeks. Worst shoulder pain in full abduction was rated on a numeric rating scale (NRS). Pain pressure thresholds (PPTs), TSP, CPM, EIH, Shoulder Pain and Disability Index (SPADI), Pain Catastrophizing Scale (PCS), PainDETECT questionnaire (PD‐Q), Pain Self‐Efficacy Questionnaire (PSE‐Q) and Pittsburgh Sleep Quality Index (PSQI) were assessed before and after intervention.

Results

The intervention improved worst pain intensity (p < 0.001), increased the CPM (p < 0.001), improved the sleep scores (p < 0.005) and reduced the PainDETECT ratings (p < 0.001). No changes were observed in PPT, TSP, EIH, SPADI, PCS and PSE‐Q (all p > 0.05). In a linear regression, the combination of all baseline parameters predicted 23.2% variance in absolute change in pain after 8 weeks. Applying backwards elimination to the linear regression yielded that baseline pain intensity combined with TSP predicted 33.8% variance.

Conclusion

This explorative study suggested reduction in pain, improved sleep quality and increased CPM after 8‐weeks of exercise. Furthermore, the results suggests that low pain intensity and high TSP scores (indicative for pain sensitisation) may predict a lack of pain improvement after exercise.

Effect of Ultrasonography-Guided Corticosteroid Injection vs Placebo Added to Exercise Therapy for Achilles Tendinopathy: A Randomized Clinical Trial

Importance

Corticosteroid injections and exercise therapy are commonly used to treat chronic midportion Achilles tendinopathy, but the evidence for this combination is limited.

Objective

To investigate the effect of corticosteroid injection and exercise therapy compared with placebo injection and exercise therapy for patients with Achilles tendinopathy.

Design, Setting, and Participants

This was a participant-blinded, physician-blinded, and assessor-blinded randomized clinical trial of patients with Achilles tendinopathy verified by ultrasonography. Assessment of pain and function were conducted at baseline and at 1, 2, 3, 6, 12, and 24 months. Patients were recruited from a university medical clinic and a private rheumatology clinic in Denmark between April 2016 and September 2018. Data analysis was performed from June to September 2021.

Interventions

Corticosteroid injection and placebo injection were performed with ultrasonography guidance. Exercise therapy was based on previous trials and consisted of 3 exercises done every second day.

Main Outcomes and Measures

The primary outcome was the Victorian Institute of Sports Assessment-Achilles (VISA-A) score (range, 1-100, with 100 representing no symptoms) at 6 months. Secondary outcomes included pain measured using a 100-mm Visual Analog Scale for morning pain and pain during exercise (with higher scores indicating worse pain), global assessment (Likert scale), and tendon thickness.

Results

A total of 100 patients were included, with 52 randomized to placebo (mean age, 46 years [95% CI, 44-48 years]; 32 men [62%]) and 48 randomized to corticosteroid injection (mean age, 47 years [95% CI, 45-49 years]; 28 men [58%]). Patients in the 2 groups had similar height (mean [SD], 177 [8] cm), weight (mean [SD], 79 [12] kg), and VISA-A score (mean [SD], 46 [18]) at baseline. The group receiving exercise therapy combined with corticosteroid injections had a 17.7-point (95% CI, 8.4-27.0 points; P < .001) larger improvement in VISA-A score compared with patients receiving exercise therapy combined with placebo injections at 6 months. No severe adverse events were observed in either group, and there was no deterioration in the long term (2-year follow-up).

Conclusions and Relevance

Corticosteroid injections combined with exercise therapy were associated with better outcomes in the treatment of Achilles tendinopathy compared with placebo injections and exercise therapy. A combination of exercise therapy and corticosteroid injection should be considered in the management of long-standing Achilles tendinopathy.

Trial Registration

ClinicalTrials.gov Identifier: NCT02580630.

Care-seeking behaviour of adolescents with patellofemoral pain: a retrospective cohort study

AIM

The aim of this study was to assess the care-seeking behaviour among adolescents with patellofemoral pain (PFP).

METHODS

This retrospective study included data on 121 adolescents with PFP enrolled in a randomized controlled trial. A questionnaire was sent to the general practitioner (GP) of each adolescent, assessing information on the consultation dates for knee pain, potential diagnoses, and treatment provided.

RESULTS

106/121 adolescents had been in contact with their GP, and 95 medical records of adolescents were available. Of the 95 adolescents with available medical records 60 had consulted their GP for knee pain. The median number of contacts was 1.5 (range 1-7). The GPs initiated treatment for 48 of the 60 adolescents and in most cases it was information and advice (36/48) or pain medication to a minor extent (6/48). Out of the 60 adolescents who consulted their GP 26 were subsequently referred to different types of health care professionals, in 11 out of 26 to physiotherapy, but also to the department of rheumatology or orthopaedics. Conclusions : 63% of adolescents diagnosed with PFP had previously consulted their GP due to knee pain. Several types of treatments were initiated by the GP, but most commonly advice and information were given. Standardized and evidence-based treatment guidelines for adolescent knee pain in general practice are needed.

Is the Prognosis of Osgood-Schlatter Poorer Than Anticipated? A Prospective Cohort Study With 24-Month Follow-up

BACKGROUND

Osgood-Schlatter disease (OSD), an apophyseal injury of the tibial tuberosity, affects up to 1 in 10 adolescents. This condition has previously been assumed to be innocuous and to self-resolve with limited intervention.

PURPOSE

To investigate the 24-month prognosis of OSD and examine if ultrasound (US) classification is associated with outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

This study included a preregistered prospective cohort of 51 adolescents (aged 10-14 years) diagnosed with OSD who were evaluated for 24 months. The primary outcome at 24-month follow-up was whether participants continued to experience OSD-related knee pain. Baseline US scans were collected and characterized by OSD type (De Flaviis classification) as well as maturation of the tibial tuberosity. Secondary outcomes included sports participation, Knee injury and Osteoarthritis Outcome Score (KOOS) Sport/Recreation subscale, and health-related quality of life (European Quality of Life-5 Dimensions-Youth [EQ-5D-Y]). All participants were invited for re-examination by US at follow-up.

RESULTS

A total of 51 patients preregistered for the study, with 90% (n = 46) available at follow-up. Of these 46 participants, 37% (n = 17) still reported knee pain due to OSD. In this subgroup, the median duration since symptom onset was 42 months (interquartile range, 38-51 months). More than 1 in 5 participants reported stopping sport due to knee pain, and those who continued to experience knee pain reported significantly worse KOOS Sport/Recreation scores at follow-up compared with patients with no knee pain (mean 74 [95% CI, 63-84] vs 91 [95% CI, 85-97]). Participants with continued OSD-related pain also had lower health-related quality of life (mean difference in EQ-5D-Y, 0.11 [95% CI, 0.06-0.13]). Higher De Flaviis classification at baseline was significantly associated with an increased risk of knee pain at 2 years. Diagnostic US at follow-up demonstrated primarily tendon changes (thickening, positive Doppler signal), as well as an ununited ossicle in 32% of participants who underwent US scanning at follow-up.

CONCLUSION

Over one-third of the study participants had knee pain at 2-year follow-up, which was associated with lower sports related function and health related quality of life. This questions the assumption that all patients with OSD experience quick recovery. Participants without any changes on imaging at baseline were less likely to report pain at follow-up.

Development and validation of the Sorting non-trauMatIc adoLescent knEe pain (SMILE) tool - a development and initial validation study

BACKGROUND

Despite the commonality of adolescent knee pain, there are no tools to support medical doctors to correctly diagnose knee pain. This study aimed to develop and evaluate a support tool for diagnosing the most common types of non-traumatic adolescent knee pain.

METHOD

A systematic search on Medline identified the literature on clinical tests and diagnoses of adolescent knee pain. The search was supplemented by textbooks and transformed into a diagnostic flowchart based on onset, symptoms, and pain localisation. This tool was revised based on feedback from general practitioners and experts in sports medicine. The tool was evaluated on two separate days with blinded assessors. Overall, 27 participants (aged 10-17 years) with non-traumatic knee pain were included. All participants were diagnosed by medical doctors or medical students, without and with the use of the tool. Diagnoses were compared to a gold standard (expert clinician). An interview to inform optimisations of the tool was performed with the assessors. Percentage agreement with the gold standard, and Kappa statistic for interrater reliability were calculated.

RESULTS

The final tool improved diagnostic agreement with the gold standard from 22.7% (95% CI 10.3-35.1) to 77.3% (95% CI 64.9-89.7). Inter-rater reliability increased from poor agreement k = - 0.04 (95% CI, - 0.12-0.04) to moderate agreement k = 0.56 (95% CI, 0.40-0.72).

CONCLUSION

This simple diagnostic tool is quick to use and may assist doctors in diagnosing non-traumatic knee pain in adolescents.

Prognosis and transition of multi-site pain during the course of 5 years: Results of knee pain and function from a prospective cohort study among 756 adolescents

INTRODUCTION

Multi-site pain has not been investigated among adolescents suffering from knee pain. This study aimed to examine the trajectory of pain in adolescents with knee-pain, to determine if multi-site pain in adolescents together with other established prognostic factors (frequency of pain, sex, sports participation, Health Related Quality of Life (HRQoL)) was associated with five-year prognosis of knee-pain and function.

METHODS

This prospective cohort study included 504 adolescents with knee pain and 252 controls. At five-year follow-up, participants responded to an questionnaire which documented prescence and severity of knee pain and co-occurring pain.

RESULTS

At follow-up, 358 (71.0%) of those with knee-pain at baseline, and 182 (72.2%) controls responded. Female sex, low HRQoL, daily pain, and multi-site pain were associated with an increased odds of knee pain after 5 years (odds ratio: 1.41-3.37). Baseline multi-site pain was not associated with problems running at follow-up, whereas higher sports participation at baseline was associated with less problems running at follow-up (odd ratio 0.49). Among those with knee-pain at inclusion, the number of pain sites increased from a median of 2 (IQR 1-3) to 4 (IQR 2-6) at follow-up (P<0.05). Those with multi-site pain at follow-up score significantly worse in self-reported knee function, compared to those with one pain site only.

CONCLUSION

This study identified a set of factors that appeared to be associated with an increased risk of knee pain at five years follow up. Research is needed to understand and help direct treatment of adolescents with multi-site pain.

Stretching and relaxing the plantar fascia may change plantar fascia thickness but not pressure pain thresholds: a cross-sectional study of patients with plantar fasciopathy

Background

Despite the established relevance of ultrasonography and assessment of pressure pain thresholds in patients with plantar fasciopathy, patient and probe positioning has been mostly ignored and are not necessarily reported in research. The primary aim of this study was to compare plantar fascia thickness in stretched and relaxed positions in patients with plantar fasciopathy. The secondary aim was to compare plantar heel pressure pain thresholds in these positions.

Methods

In this cross-sectional study, we measured the plantar fascia thickness with ultrasonography, and localised pressure pain thresholds using pressure algometry of 20 patients with plantar fasciopathy. These were assessed bilaterally, with the plantar fascia in both a stretched and relaxed position. In the stretched position, toes were maximally dorsiflexed, while in the relaxed position participants’ feet were hanging freely over the end of the table.

Results

The plantar fascia of the most symptomatic foot was significantly thicker when stretched compared with the relaxed position (sagittal: mean difference 0.2 mm, 95%CI: 0.1–0.4, P = 0.013; frontal: mean difference − 0.27, 95%CI: − 0.49 to − 0.06, P = 0.014). The plantar fascia was significantly thinner in the frontal plane compared with the sagittal plane in both positions (stretched: mean difference − 0.2 mm, 95%CI: − 0.42 to − 0.03, P = 0.025; relaxed: mean difference − 0.3 mm, 95%CI:-0.49 to − 0.08, P = 0.008). There was no difference between pressure pain thresholds in stretched or relaxed positions in either foot (P > 0.4).

Conclusions

The plantar fascia was significantly thicker in a stretched compared with a relaxed position and in the sagittal compared with the frontal plane, but differences were smaller than the standard deviation. Pressure pain thresholds were not different between the positions. These results highlight the importance of how ultrasonography is performed and reported in research to allow for replication.

Trial registration

The study was pre-registered September 25th, 2017 on ClinicalTrials.gov (NCT03291665).

Ultrasound Definitions and Findings in Greater Trochanteric Pain Syndrome: A Systematic Review

Ultrasound (US) assists in the determination of the pathology underlying greater trochanteric pain syndrome (GTPS); however, there exists no consensus regarding the US criteria used to define these pathologies. We aim to explore these US definitions and their associated prevalence. "Trochanteric bursitis" was defined in 10 studies (13 included studies) and was heterogeneously described. "Tendinopathy" was defined in 4 studies, while 7 studies defined "tendinosis." "Tendon tears" were defined in 8 studies, 6 of which distinguished between "partial- and full-thickness tears." Tendon pathology was most frequent in 5 studies (prevalence: 7%-93%), and bursitis in 2 studies (prevalence: 10%-75%); 3 studies had equal distribution. Methodological quality was limited in the descriptions of GTPS and US approaches. Together, we document the lack of standardized US definitions of the pathologies underlying GTPS. This may explain the heterogenous prevalence of US findings. Standardized definitions are needed to improve the reliability of future GTPS studies.

Corticosteroid injection plus exercise versus exercise, beyond advice and a heel cup for patients with plantar fasciopathy: protocol for a randomised clinical superiority trial (the FIX-Heel trial)

Background

Plantar fasciopathy has a lifetime prevalence of 10%. Patients experience sharp pain under the heel, often for several months or years. Multiple treatments are available, but no single treatment appears superior to the others. A corticosteroid injection offers short-term pain relief but is no better than placebo in the longer term (> 8 weeks). Heavy-slow resistance training has shown potentially positive effects on long-term outcomes (> 3 months), and combining exercises with an injection may prove to be superior to exercises alone. However, the effect of heavy-slow resistance training compared with a simpler approach of patient advice (e.g., load management) and insoles is currently unknown. This trial compares the efficacy of patient advice with patient advice plus heavy-slow resistance training and with patient advice plus heavy-slow resistance training plus a corticosteroid injection in improving the Foot Health Status Questionnaire pain score after 12 weeks in patients with plantar fasciopathy.

Methods

In this randomised superiority trial, we will recruit 180 patients with ultrasound-confirmed plantar fasciopathy and randomly allocate them to one of three groups: (1) patient advice and an insole (n = 60); (2) patient advice, an insole, and self-dosed heavy-slow resistance training consisting of heel raises (n = 60); or (3) patient advice, an insole, heavy-slow resistance training, and an ultrasound-guided corticosteroid injection (n = 60). All participants will be followed for 1 year, with the 12-week follow-up considered the primary endpoint. The primary outcome is the Foot Health Status questionnaire pain domain score. Secondary outcomes include the remaining three domains of the Foot Health Status Questionnaire, a 7-point Global Rating of Change, the Pain Self-Efficacy Questionnaire, physical activity level, health-related quality of life measured by the EQ-5D-5L, and Patient Acceptable Symptom State, which is the point at which participants feel no further need for treatment. Additionally, a health economic evaluation of the treatments will be carried out.

Discussion

This trial will test if adding heavy-slow resistance training to fundamental patient advice and an insole improves outcomes and if a corticosteroid injection adds even further to that effect in patients with plantar fasciopathy.

Trial registration

ClinicalTrials.gov, NCT03804008. Prospectively registered on January 15, 2019.

Heavy-slow resistance training in addition to an ultrasound-guided corticosteroid injection for individuals with plantar fasciopathy: a feasibility study

Introduction

Plantar fasciopathy, characterised by plantar heel pain, affects one in ten in a lifetime. Heavy-slow resistance training (HSR) is an emerging treatment, but it often takes considerable time before the effect starts to manifest. Combining HSR with a corticosteroid injection (known for its short-term pain relief) could potentially improve outcomes in both short and long term. As this combination is yet to be investigated, we aimed to evaluate the feasibility of combining HSR with a corticosteroid injection for individuals with plantar fasciopathy before investigating the efficacy in a clinical trial.

Materials and methods

We recruited 20 participants with plantar fasciopathy for this prospectively registered feasibility study (ClinicalTrials.gov: NCT03535896). Participants received an ultrasound-guided injection and performed heel raises on a step every second day for 8 weeks. To assess participant acceptability of the combined interventions and exercise compliance, we used a 7-point Likert scale dichotomised to “unacceptable” (categories 1–2) or “acceptable” (categories 3–7) and training diaries. Greater than or equal to 10/20 had to rate the combination “acceptable”, ≥ 15/20 had to perform ≥ 20 training sessions, and ≥ 15/20 had to start exercising ≤ 7 days after injection to confirm feasibility.

Results

Eighteen out of 20 rated the combination acceptable. Five training diaries could not be retrieved. Ten out of 15 participants performed ≥ 20 training sessions, and 15/15 started exercising ≤ 7 days after injection.

Conclusions

Based on participant acceptability and time to exercise start, combining HSR with corticosteroid injection is feasible and the efficacy should be investigated in a future trial. Due to loss of 5/20 training diaries, firm conclusions regarding exercise compliance could not be drawn.

Trial registration

ClinicalTrials.gov, NCT03535896

Electronic supplementary material

The online version of this article (10.1186/s40814-019-0489-3) contains supplementary material, which is available to authorized users.

Poor prognosis of child and adolescent musculoskeletal pain: a systematic literature review

OBJECTIVES

To identify baseline patient characteristics that are (1) associated with a poor outcome on follow-up regardless of which treatment was provided (prognosis) or (2) associated with a successful outcome to a specific treatment (treatment effect modifiers).

DESIGN

Systematic literature review according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines.

DATA SOURCES

Medline, Embase, Cinahl, Web of Science, Cochrane, SportDiscus, OT Seeker and PsychInfo were searched for prospective cohort studies up to February 2019 without limitation in publication date.

ELIGIBILITY CRITERIA

Prospective cohort studies reporting either prognostic factors or treatment effect modifiers on persistent musculoskeletal pain in 0-year-old to 19-year-old children and adolescents. Pain caused by tumours, fractures, infections, systemic and neurological conditions were excluded.

OUTCOME MEASURES

Our primary outcome was musculoskeletal pain at follow-up and identification of any baseline characteristics that were associated with this outcome (prognostic factors). No secondary outcomes were declared.

METHOD

Two reviewers independently screened abstracts and titles. We included prospective cohort studies investigating the prognosis or treatment effect modifiers of 0-year-old to 19-year-old children and adolescents with self-reported musculoskeletal pain. Risk of bias assessment was conducted with the Quality in Prognostic Studies tool.

RESULTS

Twenty-six studies yielding a total of 111 unique prognostic factors were included. Female sex and psychological symptoms were the most frequent investigated prognostic factors. Increasing age, generalised pain, longer pain duration and smoking were other identified prognostic factors. No treatment effect modifiers were identified.

CONCLUSION

Several prognostic factors are associated with a poor prognosis in children and adolescents with musculoskeletal pain. These prognostic factors may help guide clinical practice and shared decision-making. None of the included studies was conducted within a general practice setting which highlights an area in need of research.

PROSPERO REGISTRATION NUMBER

CRD42016041378.

Self-dosed and pre-determined progressive heavy-slow resistance training have similar effects in people with plantar fasciopathy: a randomised trial

QUESTION

For people with plantar fasciopathy, is a 12-week self-dosed heavy-slow resistance training program more beneficial than a 12-week pre-determined heavy-slow resistance training program?

DESIGN

A randomised trial with concealed allocation, partial blinding, and intention-to-treat analysis.

PARTICIPANTS

Seventy people with plantar fasciopathy confirmed on ultrasonography.

INTERVENTION

Both groups performed a repeated heel raise exercise in standing for 12 weeks. Participants in the experimental group were self-dosed (ie, they performed as many sets as possible with as heavy a load as possible, but no heavier than 8 repetition maximum). The exercise regimen for the control group was pre-determined (ie, it followed a standardised progressive protocol).

OUTCOME MEASURES

The primary outcome was the Foot Health Status Questionnaire pain domain. Secondary outcomes included: a 7-point Likert scale of Global Rating of Change dichotomised to 'improved' or 'not improved'; Patient Acceptable Symptom State defined as when participants felt no further need for treatment; and number of training sessions performed.

RESULTS

There was no significant between-group difference in the improvement of Foot Health Status Questionnaire pain after 12 weeks (adjusted MD -6.9 points, 95% CI -15.5 to 1.7). According to the Global Rating of Change, 24 of 33 in the experimental group and 20 of 32 in the control group were improved (RR = 1.16, 95% CI 0.83 to 1.64). Only four participants achieved Patient Acceptable Symptom State: three of 35 in the experimental group and one of 35 in the control group. No significant between-group difference was found in the number of training sessions that were performed (MD -2 sessions, 95% CI -8 to 3).

CONCLUSION

Self-dosed and pre-determined heavy-slow resistance exercise programs are associated with similar effects on plantar fasciopathy pain and other outcomes over 12 weeks. Advising people with plantar fasciopathy to self-dose their slow-heavy resistance training regimen did not substantially increase the achieved dose compared with a pre-determined regimen. These regimens are not sufficient to achieve acceptable symptom state in the majority of people with plantar fasciopathy.

REGISTRATION

ClinicalTrials.govNCT03304353.

Five-year prognosis and impact of adolescent knee pain: a prospective population-based cohort study of 504 adolescents in Denmark

OBJECTIVES

Investigate the prognosis of adolescent knee pain, and evaluate its impact on health, care-seeking and career choices 5 years later.

DESIGN

Pre-registered, prospective cohort study.

SETTING

Population-based cohort initiated in school setting.

PARTICIPANTS

From a cohort of 2200 adolescents aged 15-19 years in 2011, 504 reported knee pain on at least a monthly basis, and were followed prospectively in this cohort study, together with 252 controls who did not have knee pain in 2011.

MAIN OUTCOME MEASURES

Outcomes included the Pain and Symptoms subscales from the Knee injury and Osteoarthritis Outcome Score (KOOS), pain intensity measured with a Numeric Rating Scale, pain frequency, knee-related and health-related quality of life, sports participation, physical activity level, KOOS subscales: Function and Sport/recreation, quality of sleep, healthcare consultations, treatments received for their knee pain, the use of painkillers and impact on choice of job or career.

RESULTS

At follow-up, 358 (71.0%) from the knee pain group and 182 (72.2%) from the control group responded. Of note, 40.5% (95% CI: 35.4% to 45.6%) from the knee pain group reported knee pain 5 years later which was frequent and intense compared with 13.2% (95% CI: 8.2 to 18.1) of the control group. Those from the knee pain group still suffering from knee pain reported poorer physical health (13 points worse on KOOS Function and 30 points worse on KOOS Sport/recreation), stopped or reduced their sports participation because of knee pain (60%), reported worse sleep quality and worse knee-related and general quality of life. In terms of health behaviours, those still with knee pain reported more healthcare consultations. One-third used pain killers regularly, and 15% (95% CI: 12% to 20%) reported that knee pain influenced their choice of job or career.

CONCLUSION

Four out of every 10 adolescents with knee pain still experienced frequent and intense knee pain 5 years later, severe enough to impact health, health behaviours and career choices.

TRAIL REGISTRATION NUMBER

NCT02873143.

Prevalence and incidence rate of lower-extremity tendinopathies in a Danish general practice: a registry-based study

Background

Tendinopathies of the lower extremity (e.g. Achilles, patellar, and plantar heel pain) are common in both general and sporting populations. However, the prevalence and incidence in Danish general practice is unknown. The aim was to determine the prevalence and incidence rate of lower-extremity tendinopathies in a Danish general practice.

Methods

In this registry-based study, we extracted data from the electronic patient files of all patients in a single Danish general practice. The practice included 8836 patients. We searched ICPC-2 codes to identify patients with either of the following lower-extremity tendinopathies: plantar heel pain; Achilles tendinopathy; patellar tendinopathy; greater trochanteric pain syndrome or adductor tendinopathy. We defined an incident and prevalent case as a patient with a consultation because of tendinopathy in 2016 only. A prevalent, but not incident case was a patient with consultations in both 2015 and 2016. Incidence and prevalence were expressed as the number of patients with a tendinopathy per 1000 registered patients.

Results

The prevalence and incidence rate were 16.6 and 7.9 per 1000 registered patients, respectively. Plantar heel pain was the most prevalent tendinopathy and accounted for 39% of lower-extremity tendinopathies. Patients with tendinopathies were significantly older than all registered patients (46.0 years (95%CI: 43.3;48.7) versus 38.8 years (95%CI: 38.4;39.3), respectively).

Conclusions

Lower-extremity tendinopathies, especially plantar heel pain, had a high prevalence and incidence rate in a Danish general practice. In a typical general practice with 5000 patients, general practitioners should expect to see more than 80 patients with a lower-extremity tendinopathy every year.

Translation and cultural adaptation of a Danish version of the Foot Health Status Questionnaire for individuals with plantar heel pain

BACKGROUND

The Foot Health Status Questionnaire (FHSQ) is recommended as a valid and reliable patient-reported outcome for individuals with plantar heel pain (PHP). The aim of this study was to translate and culturally adapt the FHSQ into Danish and investigate face and construct validity among patients with PHP.

METHODS

The translation was made using the dual-panel approach. The first panel of bilingual translators translated the questionnaire and the translation was then presented to a lay panel who reviewed and revised the translated version. This version was presented to patients with PHP (n=6) who were interviewed about the comprehensibility, if they found it easy to fill out, and if they found the questionnaire to be relevant to them. Correlation between mean weekly heel pain and FHSQ scores were used to assess construct validity in another patient sample (n=30).

RESULTS

The first panel of five translators reached consensus on all 13 items. The layman panel of five participants rephrased two items. Both the layman panel and patients had difficulties with differentiating between items 12 and 13 but concluded that making better phrasings that would work in Danish was not possible. The questionnaire was evaluated as relevant and comprehensible. No revisions were made after the interviews. Pain and function domains correlated with heel pain but not footwear or general foot health.

CONCLUSION

The FHSQ was translated into a Danish version (FHSQ-DK) which demonstrated both face and construct validity. More psychometric properties of the FHSQ-DK should be established in future studies.

[Medical risks in extreme sports]

The boundaries for what is characterised as extreme sport are constantly expanding, and the activities are becoming more and more strenuous with medical hazards for the athletes. This review is a description of: 1) athletes' most common medical risks and 2) a series of precautions.

[Tendinopathy in athletes]

Tendinopathy is a condition of tendon overuse and is a very common cause of morbidity among recreational and competitive athletes. Chronic overload results in degenerative changes of the tendon, which becomes painful and swollen with impaired function. A reduction in the overloading activity is the mainstay of the treatment. A rehabilitating programme consisting of controlled loading of the affected tendon should follow this. Other modalities, which may facilitate treatment, are: injections with corticosteroid, platelet-rich plasma, and of high volume, as well as shock-wave therapy and surgery.

The effect of isometric exercise on pain in individuals with plantar fasciopathy: A randomized crossover trial

Isometric exercise is commonly recommended for immediate pain relief in individuals suffering from lower limb tendinopathies, despite the limited evidence supporting its analgesic effect. Due to the similarities between plantar fasciopathy and tendinopathies, the aim of this trial was to investigate the acute effect of isometric exercise on pain, compared to isotonic exercise, or walking, in individuals with plantar fasciopathy. We recruited 20 individuals with plantar fasciopathy for this prospectively-registered, participant-blinded, randomized, superiority crossover trial (ClinicalTrials.gov: NCT03264729). Participants attended three exercise sessions (isometric, isotonic, or walking) in a randomized order, within a 2-week period. Both isometric and isotonic exercises were performed standing with the forefoot on a step bench, while walking was performed barefoot. The primary outcome was pain (measured on a 0-100-mm VAS) during a pain-aggravating activity. Secondary outcomes included pressure pain threshold (PPT) under the heel, and plantar fascia thickness (PFT). All outcomes were measured before and after each exercise session. There were no significant differences between the three exercises on pain (P = 0.753), PPTs (P = 0.837), or PFT (P = 0.718). Further, there was no change in pain from before to after any of the exercises (isometric exercise 2.7 mm [95% CI: -12.2; 6.8], isotonic exercise -3.4 mm [95% CI: -5.0; 11.8], or walking 1.6 mm [95% CI: -16.1; 12.9]). Contrary to expectations, isometric exercise was no better than isotonic exercise or walking at reducing pain in individuals with plantar fasciopathy. None of the exercises induced any systematic analgesic effect.

[Treatment of patellofemoral pain includes more than knee rehabiliation]

Patellofemoral pain is a debilitating condition which affects one in 14 adolescents and a similar number of adults. It is characterized by peri- or retropatellar pain during loaded bending of the knee. The purpose of this review is to provide a short, up-to-date review of the diagnostics, differential diagnostics and evidence-based treatment for both adolescents and adults with patellofemoral pain. The key message is that treatments of patellofemoral pain should include a combination of patient education to support self-management and exercises to strengthen the hip and knee muscles.

[Periostal avulsion of m. vastus medialis in a triathlete during competition]

Periostal avulsion of m. vastus medialis is a very rare injury. To our knowledge, it has not previously been described, and there is no treatment algorithm. A 32-year-old male professional triathlete experienced this type of injury during a final sprint in a competition. He achieved a good functional result after treatment with an optimal rehabilitation regimen, and approximately four months after the injury he won a medal in a major international event.

Assessment of enthesitis in patients with psoriatic arthritis using clinical examination and ultrasound

BACKGROUND

Enthesitis is a major feature of psoriatic arthritis. However, clinical assessment of enthesitis is known to lack accuracy and have poor interobserver reliability.

OBJECTIVE

To determine effect of training on clinical assessment of enthesitis and to compare ultrasonography with clinical examination for the detection of entheseal abnormalities.

METHODS

20 rheumatologists performed repeated assessment of enthesitis in patients with established psoriatic arthritis before and after a 2-hour training session in standardised enthesitis count according to Leeds Enthesitis Index (LEI) and Spondyloarthritis Research Consortium of Canada Enthesitis Index (SPARCC). Moreover, 20 patients underwent clinical and ultrasonographic examination of entheses to evaluate consensus-based elementary lesions of enthesitis.

RESULTS

Training significantly increased Intra-class Correlation Coefficient for LEI from 0.18 to 0.82 and for SPARCC from 0.38 to 0.67. Ultrasound examination showed high associations between hypoechogenicity and increased thickness of the entheses and clinical examination. There was no correlation between erosions and enthesophytes found by ultrasound and clinical assessments.

CONCLUSION

Training in standardised enthesitis scoring systems significantly improved clinical assessments of enthesitis and should be performed before use in daily clinical practice. Ultrasound revealed more advanced stages of enthesitis, such as enthesophytes and erosions, which were not detected with clinical examination.

Hip and knee strength is not affected in 12-16 year old adolescents with patellofemoral pain--a cross-sectional population-based study

Background

One of the rationales behind using strength training in the treatment of adolescents with Patellofemoral Pain (PFP) is that reduced strength of the lower extremity is a risk factor for PFP and a common deficit. This rationale is based on research conducted on adolescents >15 years of age but has never been investigated among young adolescents with PFP.

Objectives

To compare isometric muscle strength of the lower extremity among adolescents with PFP compared to age- and gender-matched pain-free adolescents.

Methods

In 2011 a population-based cohort (APA2011-cohort) consisting of 768 adolescents aged 12–15 years from 8 local schools was formed. In September 2012, all adolescents who reported knee pain in September 2011 were offered a clinical examination if they still had knee pain. From these, 20 adolescents (16 females) were diagnosed with PFP. Pain-free adolescents from the APA2011-cohort (n = 20) were recruited on random basis as age- and gender-matched pairs. Primary outcome was isometric knee extension strength normalized to body weight (%BW) and blinded towards subject information. Secondary outcomes included knee flexion, hip abduction/adduction and hip internal/external rotation strength. Demographic data included Knee Injury and Osteoarthritis Outcome Score (KOOS) and symptom duration.

Results

Adolescents with PFP reported long symptom duration and significantly worse KOOS scores compared to pain-free adolescents. There were no significant differences in isometric knee extension strength (Δ0.3% BW, p = 0.97), isometric knee flexion strength (Δ0.4% BW, p = 0.84) or different measures of hip strength (Δ0.4 to 1.1% BW, p>0.35).

Conclusion

Young symptomatic adolescents with PFP between 12 and 16 years of age did not have decreased isometric muscle strength of the knee and hip. These results question the rationale of targeting strength deficits in the treatment of adolescents with PFP. However, strength training may still be an effective treatment for those individuals with PFP suffering from strength deficits.

Half of 12-15-year-olds with knee pain still have pain after one year

INTRODUCTION

Adolescent knee pain is considered benign and presumed to disappear without treatment. However, this has never been investigated. The purpose of this study was to 1) compare leisure time sports participation, health-related quality of life (HRQoL) and body mass index between adolescents with and without self-reported knee pain, 2) investigate how many adolescents still have knee pain after one year and 3) identify risk factors for one-year persistence of knee pain.

MATERIAL AND METHODS

The design was a prospective cohort study and a nested case-control study. In September 2011, a total of 768 adolescents between 12-15 years of age from schools in the municipality of Aalborg answered a questionnaire on demographics, sports participation, current pain and HRQoL. After one year, adolescents who reported knee pain at first contact were again contacted by telephone and asked if they experienced knee pain.

RESULTS

At first contact, 215 adolescents reported knee pain. Adolescents with knee pain had a significantly higher leisure time sports participation level and a lower HRQoL than adolescents without knee pain. 48.8% (n = 80) still reported knee pain after one year. Female gender, taking part in sports more than twice weekly, lower HRQoL and daily knee pain increased the risk of reporting knee pain after one year.

CONCLUSION

Adolescents with self-reported knee pain participate in more leisure time sports and have a lower HRQoL than adolescents without knee pain. 50% had persistent long-lasting knee pain, and a higher frequency of leisure time sports participation increased the risk of reporting knee pain after one year.

FUNDING

Danish Rheumatism Association, The Association of Danish Physiotherapists Research Fund and The Obel Family Foundation. None of the funders have any role in the study other than to provide funding.

TRIAL REGISTRATION

Ethical approval was obtained from the local ethics committee in the North Denmark Region (N-20110020).

Novel stretch-sensor technology allows quantification of adherence and quality of home-exercises: a validation study

OBJECTIVE

To investigate if a new stretch sensor attached to an elastic exercise band can assist health professionals in evaluating adherence to home exercises. More specifically, the study investigated whether health professionals can differentiate elastic band exercises performed as prescribed, from exercises not performed as prescribed.

METHODS

10 participants performed four different shoulder-abduction exercises in two rounds (80 exercise scenarios in total). The scenarios were (1) low contraction speed, full range of motion (0-90°), (2) high contraction speed, full range of motion (0-90°), (3) low contraction speed, diminished range of motion (0-45°) and (4) unsystematic pull of the elastic exercise band. Stretch-sensor readings from each participant were recorded and presented randomly to the raters. Two raters were asked to differentiate between unsystematic pull (scenario 4), from shoulder abduction strength exercises (scenarios 1-3). The next two raters were asked to identify the four different exercise scenarios (scenarios 1-4).

RESULTS

The first two raters were able to differentiate between unsystematic pull (scenario 4) from shoulder abduction strength exercises (scenarios 1-3). They made no errors (100% success rate). The second two raters were both able to identify each of the 80 scenarios (scenarios 1-4). They too made no errors (100% success rate).

CONCLUSIONS

The stretch-sensor readings from the elastic exercise band allow health professionals to quantify whether strength-exercises have been performed as prescribed. These findings have great implications for future clinical practice and research where home exercises are the drugs-of-choice, as they enable clinicians and researchers to measure the exact adherence and quality of the prescribed exercises.

The influence of time-of-day variation and loading on the aponeurosis plantaris pedis: an ultrasonographic study

AIM

The aim of this paper was to investigate the effect of time-of-day on the thickness of the the aponeurosis plantaris pedis, and to examine the acute effects of high-load strength training and long distance running on the thickness of the aponeurosis plantaris pedis.

METHODS

Proximal aponeurosis plantaris pedis thickness was assessed with a 13-MHz linear-array transducer. In sub-study 1, ten participants (ten aponeurosis') were measured five times during 24 hours. In sub-study 2, ten participants (ten aponeurosis') were measured just before, immediately after and again three hours after 3x12 unilateral heel-rises. In sub-study 3, 11 healthy experienced runners (11 aponeurosis') were measured just before, immediately after and two hours after a 15km run. The average thickness of three scans of each foot was used in the analysis. The data was analysed using repeated measures one-way ANOVA.

RESULTS

The mean thickness of the aponeurosis plantaris pedis' fluctuated significantly during the 24 hours (p=0,02), but it did not change in relation to the high-load strength training (p=0,86) or 15km of running (p = 0,70).

CONCLUSION

High-load strength training and long distance running do not induce changes in the thickness of the aponeurosis plantaris pedis. Time-of-day influences the thickness of the aponeurosis plantaris pedis, but the changes are not larger than measurement uncertainty.

[Unsatisfactory long-term prognosis of conservative treatment of patellofemoral pain syndrome]

This review overviews the long-term prognosis of conservatively treated patients with patellofemoral pain syndrome (PFPS). Median values of the 16 included studies show that 29% of soldiers, 27.8% of sports active and 24,7% of the general public will become pain free after they are diagnosed with PFPS. 21.5% of sports active and 23% of the general public diagnosed with PFPS will stop participating in sports because of knee pain. There is an indication that around one third diagnosed with PFPS will become pain free and one fourth will stop participating in sports because of knee pain.

Intra- and interobserver reliability of quantitative ultrasound measurement of the plantar fascia

PURPOSE

To determine intra- and interobserver reliability and measurement precision of sonographic assessment of plantar fascia thickness when using one, the mean of two, or the mean of three measurements.

METHODS

Two experienced observers scanned 20 healthy subjects twice with 60 minutes between test and retest. A GE LOGIQe ultrasound scanner was used in the study. The built-in software in the scanner was used to measure the thickness of the plantar fascia (PF). Reliability was calculated using intraclass correlation coefficient (ICC) and limits of agreement (LOA).

RESULTS

Intraobserver reliability (ICC) using one measurement was 0.50 for one observer and 0.52 for the other, and using the mean of three measurements intraobserver reliability increased up to 0.77 and 0.67, respectively. Interobserver reliability (ICC) when using one measurement was 0.62 and increased to 0.82 when using the average of three measurements. LOA showed that when using the average of three measurements, LOA decreased to 0.6 mm, corresponding to 17.5% of the mean thickness of the PF.

CONCLUSIONS

The results showed that reliability increases when using the mean of three measurements compared with one. Limits of agreement based on intratester reliability shows that changes in thickness that are larger than 0.6 mm can be considered actual changes in thickness and not a result of measurement error.

Effects of resistance training on endurance capacity and muscle fiber composition in young top-level cyclists

Equivocal findings exist on the effect of concurrent strength (S) and endurance (E) training on endurance performance and muscle morphology. Further, the influence of concurrent SE training on muscle fiber-type composition, vascularization and endurance capacity remains unknown in top-level endurance athletes. The present study examined the effect of 16 weeks of concurrent SE training on maximal muscle strength (MVC), contractile rate of force development (RFD), muscle fiber morphology and composition, capillarization, aerobic power (VO2max), cycling economy (CE) and long/short-term endurance capacity in young elite competitive cyclists (n=14). MVC and RFD increased 12-20% with SE (P<0.01) but not E. VO2max remained unchanged. CE improved in E to reach values seen in SE. Short-term (5-min) endurance performance increased (3-4%) after SE and E (P<0.05), whereas 45-min endurance capacity increased (8%) with SE only (P<0.05). Type IIA fiber proportions increased and type IIX proportions decreased after SE training (P<0.05) with no change in E. Muscle fiber area and capillarization remained unchanged. In conclusion, concurrent strength/endurance training in young elite competitive cyclists led to an improved 45-min time-trial endurance capacity that was accompanied by an increased proportion of type IIA muscle fibers and gains in MVC and RFD, while capillarization remained unaffected.

Non-linear analysis of the structure of variability in midfoot kinematics

INTRODUCTION

Evaluation of structural variability in biological time series through measures such as sample entropy (SaEn) has provided important information in neurology and cardiology. This has contributed to the development of the "loss of complexity hypothesis" where high variability has been described as healthy flexibility and low variability associated with pathology. The purpose of this study was to calculate sample entropy (SaEn) to establish normal values of non-linear variability and to examine which factors are associated with SaEn in midfoot kinematics.

METHOD

Static foot posture was measured using Foot Posture Index. A video sequence analysis system was used to quantify midfoot kinematics during walking in the sagittal plane. SaEn was calculated for navicular drop during stand phase as an expression of the dynamic complexity.

RESULTS

A significant difference was observed between the three major foot types and between genders (p<0.001). Mean SaEn in women were 1.10+/-0.19 (supinated foot posture), 0.96+/-0.17 (neutral foot posture) and 0.77+/-0.16 (pronated foot posture) and 1.25+/-0.24 (supinated foot posture), 1.06+/-0.23 (neutral foot posture) and 0.86+/-0.19 (pronated foot posture) in males. The regression model showed that foot posture and dynamic navicular drop (dND) were both associated with SaEn.

CONCLUSION

This study confirmed that non-linear analysis is of relevance in the interpretation of kinematic data. Pronated foot posture, large navicular drop and women were characterized by low values of non-linear variability. Future studies should investigate if measurements of SaEn are capable of identifying subjects with an increased risk of injury.

Determination of markers for collagen type I turnover in peritendinous human tissue by microdialysis: effect of catheter types and insertion trauma

OBJECTIVES

Previous results from our group have shown that loading of human tendon elevates tendinous type I collagen production measured by microdialysis. However, exclusion of the observed elevation as a response to trauma from inserting the microdialysis catheters or a possible influence from the collagen production in skin was not determined.

METHODS

Using the microdialysis method we measured the tissue levels of type I collagen metabolism markers [procollagen I COOH-terminal propeptide (PICP) and COOH-terminal telopeptide of type I collagen (ICTP)] in peritendinous tissue of the Achilles tendon in volunteers at two time points, 0 and 72 h. Using two different catheter types, an investigation of the contribution from the skin in the collagen results obtained was also examined.

RESULTS

The data showed no significant changes in the dialysate levels for PICP or ICTP (p>0.05) in either of the catheters.

CONCLUSION

Inserting microdialysis fibres around the Achilles tendon twice does not increase the collagen type I metabolism determined 3 days after the initial trauma, and when using microdialysis for measuring peritendinous collagen turnover the skin contribution can be regarded as negligible. These findings support microdialysis as a valid method for the determination of collagen metabolism in peritendinous tissue.

Effect of unloading followed by reloading on expression of collagen and related growth factors in rat tendon and muscle

Tendon tissue and the extracellular matrix of skeletal muscle respond to mechanical loading by increased collagen expression and synthesis. This response is likely a secondary effect of a mechanically induced expression of growth factors, including transforming growth factor-beta1 (TGF-beta1) and insulin-like growth factor-I (IGF-I). It is not known whether unloading of tendon tissue can reduce the expression of collagen and collagen-inducing growth factors. Furthermore, the coordinated response of tendon and muscle tissue to disuse, followed by reloading, is unclear. Female Sprague-Dawley rats were subjected to hindlimb suspension (HS) for 7 or 14 days, followed by 2, 4, 8, or 16 days of reload (RL) (n = 8 in each group). Age-matched controls were included for day 0, day 14 HS, and day 16 RL (n = 8). mRNA expression levels for collagen I (COL1A1), collagen III (COL3A1), TGF-beta1, connective tissue growth factor (CTGF), myostatin, and IGF-I isoforms were measured by real-time RT-PCR in Achilles tendon and soleus muscle. The tendon mass was unchanged, while the muscle mass was reduced by 50% after HS (P < 0.05) and returned to control levels during RL. Collagen I and III, TGF-beta1, and CTGF mRNA levels were unaltered by HS, although collagen III tended to decrease in muscle at day 7 HS. IGF-I isoforms were significantly induced in tendon after 7 days of HS (P < 0.001), and mechanogrowth factor increased in muscle at day 14 HS (P < 0.05). Reload increased muscle collagen I and III mRNA (>10-fold) (P < 0.001) and growth factor expression (P < 0.05), while the tendon response was limited to a moderate induction of collagen expression (2-fold) (P < 0.05). Unloading of tendon and muscle tissue did not reduce expression of collagen and collagen-inducing growth factors, indicating that the response to unloading is not opposite that of loading. Furthermore, the tendon response was clearly different and less pronounced than the muscle tissue response.

Expression of collagen and related growth factors in rat tendon and skeletal muscle in response to specific contraction types

Acute exercise induces collagen synthesis in both tendon and muscle, indicating an adaptive response in the connective tissue of the muscle-tendon unit. However, the mechanisms of this adaptation, potentially involving collagen-inducing growth factors (such as transforming growth factor-beta-1 (TGF-beta-1)), as well as enzymes related to collagen processing, are not clear. Furthermore, possible differential effects of specific contraction types on collagen regulation have not been investigated. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve. RNA was extracted from medial gastrocnemius and Achilles tendon tissue 24 h after the last training bout, and mRNA levels for collagens I and III, TGF-beta-1, connective tissue growth factor (CTGF), lysyl oxidase (LOX), metalloproteinases (MMP-2 and -9) and their inhibitors (TIMP-1 and 2) were measured by Northern blotting and/or real-time PCR. In tendon, expression of TGF-beta-1 and collagens I and III (but not CTGF) increased in response to all types of training. Similarly, enzymes/factors involved in collagen processing were induced in tendon, especially LOX (up to 37-fold), which could indicate a loading-induced increase in cross-linking of tendon collagen. In skeletal muscle, a similar regulation of gene expression was observed, but in contrast to the tendon response, the effect of eccentric training was significantly greater than the effect of concentric training on the expression of several transcripts. In conclusion, the study supports an involvement of TGF-beta-1 in loading-induced collagen synthesis in the muscle-tendon unit and importantly, it indicates that muscle tissue is more sensitive than tendon to the specific mechanical stimulus.

Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon: differential effects of specific contraction types

In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types on regulation of these factors in muscle are still unclear, and in tendon the functions of myostatin, IGF-IEa, and MGF in relation to training are unknown. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric, or isometric training ( n = 7–9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve during general anesthesia. mRNA levels for myostatin, IGF-IEa, and MGF in muscle and Achilles' tendon were measured by real-time RT-PCR. Muscle myostatin mRNA decreased in response to all types of training (2- to 8-fold) ( P < 0.05), but the effect of eccentric training was greater than concentric and isometric training ( P < 0.05). In tendon, myostatin mRNA was detected, but no changes were seen after exercise. IGF-IEa and MGF increased in muscle (up to 15-fold) and tendon (up to 4-fold) in response to training ( P < 0.01). In tendon no difference was seen between training types, but in muscle the effect of eccentric training was greater than concentric training for both IGF-IEa and MGF ( P < 0.05), and for IGF-IEa isometric training had greater effect than concentric ( P < 0.05). The results indicate a possible role for IGF-IEa and MGF in adaptation of tendon to training, and the combined changes in myostatin and IGF-IEa/MGF expression could explain the important effect of eccentric actions for muscle hypertrophy.

Metabolic activity and collagen turnover in human tendon in response to physical activity

Connective tissue of the human tendon plays an important role in force transmission. The extracellular matrix turnover of tendon is influenced by physical activity. Blood flow, oxygen demand, and the level of collagen synthesis and matrix metalloproteinases increase with mechanical loading. Gene transcription and especially post-translational modifications of proteins of the extracellular matrix are enhanced following exercise. Conversely, inactivity markedly decreases collagen turnover. Training leads to a chronically increased collagen turnover, and dependent on the type of collagen also to some degree of net collagen synthesis. These changes modify the biomechanical properties of the tissue (for example, viscoelastic characteristics) as well as the structural properties of the in collagen (for example, cross-sectional area). Mechanical loading of human tendon does result in a marked interstitial increase in growth factors that are known potentially to stimulate synthesis of collagen and other extracellular matrix proteins. Taken together, human tendon tissue mounts a vigorous acute and chronic response to mechanical loading in terms of metabolic-circulatory changes as well as of extracellular matrix formation. These changes may contribute to training-induced adaptation of biomechanical properties consisting of altered resistance to loading and enhanced tolerance to strenuous exercise. Understanding of such changes is a pre-requisite in the development of measures aimed at prevention of overuse tendon injuries occurring during sport, work or leisure-related activities.