Good physical function but reduced quality of life in children 3 years after ACL reconstruction.

PURPOSE: To assess children's physical function and subjective knee status 1 and 3 years after anterior cruciate ligament (ACL) reconstruction. It was hypothesised that there was no difference between the operated and normal legs in relation to physical strength and function, that there was <-2 mm side-to-side difference in knee laxity, and that the subjective knee function was better 3 years after ACL reconstruction compared to 1 year after. METHODS: Children (<16 years of age) who had an ACL reconstruction had follow-up with physical function tests (four hop tests and strength measurement in a power rig [PR]), anterior knee laxity (measured using a Rolimeter) and patient-reported outcome measures (Pedi-International Knee Documentation Committee [IKDC] and Knee injury and Osteoarthritis Outcome Score [KOOS]-Child) 1 and 3 years postoperatively. Changes from 1- to 3-year follow-up were evaluated with a paired t test. RESULTS: Out of 148 ACL reconstructed children, 60 had all measures. The four hop tests and the PR all yielded a Limb Symmetry Index >90% at both follow-ups. There was a significant improvement from 1- to 3-year follow-up in two-hop tests (6 m on time and crossover hop). Side-to-side knee laxity was >2 mm in four children at 1- and 3-year tests. Pedi-IKDC scores increased, and KOOS-Child improved significantly from 1 to 3 years in two of the five domains: 'Sport' and 'Quality of life', but scores were lower than in a cohort of normal children. CONCLUSION: The children had good objective physical function 1 and 3 years after ACL reconstruction. However, scores from the KOOS-Child sport-specific function and quality of life domains were lower than in normal children. LEVEL OF EVIDENCE: Level II.

Reliability and Validity of the End Range Hamstring Strength Test with Handheld Dynamometry.

Background and Purpose: Hamstring strength testing is crucial in assessing this important muscle group during rehabilitation and injury prevention. The purpose of this study was to evaluate the reliability and validity of measuring strength in a maximally lengthened position using a handheld dynamometer (HHD) compared to isokinetic testing. Methods: Twenty healthy and active participants were recruited, and isometric strength testing was performed both on the Biodex machine and isometric end-range hamstring testing with the HHD on two occasions. Results: Significant strong correlations (r= 0.87, p < 0.0001) were found between strength testing on the Biodex machine and the HHD for both the right and left sides. Bland-Altman plots demonstrated agreement between the two measurements. Excellent intra-rater reliability (ICC= 0.91-0.93) and moderate to good inter-rater reliability (ICC = 0.71-0.83) for the HHD test was demonstrated. Conclusions: The HHD provides a reliable and valid alternative to isokinetic testing for assessing hamstring strength in a maximally lengthened position. This assessment can be valuable in monitoring rehabilitation progress and detecting deficits before and after returning to play. The HHD is an accessible and cost-effective option for assessing hamstring strength at long lengths in a clinical setting. Level of evidence: 3.

The relationship between ultrasonography with or without contrast and the clinical outcome in plantar fasciitis.

BACKGROUND: Plantar fasciitis (PF) is a common disorder without objective parameters for disease severity. PURPOSE: To investigate whether structural changes in the plantar fascia and heel fat pad determined by ultrasound scanning with or without contrast are related to outcome measures in patients with symptomatic PF and to investigate whether there is an association between changes in US findings and improvement in pain and function. METHODS: All patients (n = 90) in a randomized controlled trial treated with training and/or glucocorticosteroid injection were assessed for morning pain, function pain, Foot Function Index (FFI), and ultrasound measured thickness of the fascia and heel fat pad at entry and after 6 months. Thirty patients were included in a longitudinal study that assessed pain, function, and microvascular volume (MV) by contrast-enhanced ultrasound at entry and after 5 months of treatment. RESULTS: None of the ultrasound parameters at the initial examination were related to clinical outcomes at 5-6 months. Changes in US measured thickness of the fascia but not the fat pad correlated with improvement in all outcome measures at 6 months (FFI: r = 0.30, p = 0.005, morning pain: r = 0.21, p = 0.046, function pain: r = 0.28, p = 0.007). MV did not change despite significant improvement in symptoms. CONCLUSION: Changes in ultrasound measured fascia thickness are associated with clinical improvement in PF patients.

Effects of Heavy Slow Resistance Training Combined With Corticosteroid Injections or Tendon Needling in Patients With Lateral Elbow Tendinopathy: A 3-Arm Randomized Double-Blinded Placebo-Controlled Study.

BACKGROUND: Lateral elbow tendinopathy is a disabling tendon overuse injury. It remains unknown if a corticosteroid injection (CSI) or tendon needling (TN) combined with heavy slow resistance (HSR) training is superior to HSR alone in treating lateral elbow tendinopathy. PURPOSE/HYPOTHESIS: The purpose was to investigate the effects of HSR combined with either (1) a CSI, (2) TN, or (3) placebo needling (PN) as treatment for lateral elbow tendinopathy. We hypothesized that 12 weeks of HSR in combination with a CSI or TN would have superior effects compared with PN at 12, 26, and 52 (primary endpoint) weeks' follow-up on primary (Disabilities of the Arm, Shoulder and Hand [DASH] score) and secondary outcomes in patients with chronic unilateral lateral elbow tendinopathy. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 60 patients with chronic unilateral lateral elbow tendinopathy were randomized to perform 12 weeks of home-based HSR with elastic band exercises combined with either (1) a CSI, (2) TN, or (3) PN, and at 12, 26, and 52 weeks, we assessed the primary outcome, the DASH score, and secondary outcomes: shortened version of the DASH (QuickDASH) score, pain (numerical rating scale [NRS] score), pain-free grip strength, and hypervascularization (power Doppler area). RESULTS: A CSI, TN, and PN improved patient outcomes equally based on the DASH (Δ20 points), QuickDASH (Δ21 points), and NRS (Δ2.5 points) scores after 12 weeks. Further, after 12 weeks, a CSI also resulted in decreased hypervascularization (power Doppler area) compared with PN (Δ-2251 pixels, P = .0418). Except for the QuickDASH score (CSI increased score by Δ15 points compared with PN; P = .0427), there were no differences between the groups after 52 weeks. CONCLUSION: These results suggest that 12 weeks of HSR improved symptoms in both the short and the long term and that a CSI or TN did not amplify this effect. In addition, a CSI seemed to impair patient-reported outcomes compared with HSR alone at long-term follow-up. REGISTRATION: NCT02521298 (ClinicalTrials.gov identifier).

Persistent Deficits after an Achilles Tendon Rupture: A Narrative Review.

Persistent muscle weakness, tendon elongation, and incomplete return to preinjury level are frequent sequelae after acute Achilles tendon rupture, and evidence-based knowledge of how to best rehabilitate the injury is largely absent in the literature. The objective of this review is to illuminate and discuss to what extent an Achilles tendon rupture affects muscle, tendon, and function when assessed with the Achilles tendon total rupture score (ATRS), muscle strength, muscle cross-sectional area, tendon length, and the heel-rise test. The patient-reported outcome measures (PROM) data in the literature suggest that the recovery takes longer than 6 months (ATRS, 70 out of 100), that one-year postinjury, the ATRS only reaches 82, and that this does not appear to noticeably improve thereafter. Loss of muscle mass, strength, and function can in some cases be permanent. Over the first 6 months postinjury, the tendon undergoes elongation, which appears to be negatively correlated to heel-rise function. More recently, there has been some interest in how muscle length and excursion is related to the reduced function. The available literature indicates that further research is highly warranted and that efforts to restore normal tendon length may improve the likelihood of returning to preinjury level after an Achilles tendon rupture.

Chronic hyperglycemia, hypercholesterolemia, and metabolic syndrome are associated with risk of tendon injury.

Tendon injury is a considerable problem affecting both physically active and sedentary people. The aim of this study was to examine the relationship between markers for metabolic disorders (hyperglycemia, hypercholesterolemia, and metabolic syndrome) and the risk of developing tendon injuries requiring referral to a hospital. The Copenhagen City Heart Study is a prospective study of diabetic and non-diabetic individuals from the Danish general population with different physical activity levels. The cohort was followed for 3 years via national registers with respect to tendon injuries. Data from 5856 individuals (median age 62 years) were included. The overall incidence of tendon injury in both upper and lower extremities that required an out-patient or in-house visit to a hospital was ~5.7/1000 person years. Individuals with elevated HbA1c (glycated hemoglobin) even in the prediabetic range (HbA1c>5.7%) had a ~3 times higher risk of tendon injury in the lower extremities only, as compared to individuals with normal HbA1C levels. Hypercholesterolemia (total cholesterol>5 mmol/L) increased risk of tendon injury in the upper extremities by ~1.5 times, and individuals with metabolic syndrome had ~2.5 times higher risk of tendon injury in both upper and lower extremities. In conclusion, these data demonstrate for the first time in a large cohort with different physical activity levels that the indicators for metabolic syndrome are a powerful systemic determinant of tendon injury, and two of its components, hyperglycemia and hypercholesterolemia, each independently make tendons susceptible for damage and injury.

Acromio-Humeral Distance Is Associated with Shoulder External Strength in National Elite Badminton Players-A Preliminary Study.

PURPOSE: To examine acromio-humeral distance (AHD) and shoulder isometric strength for external rotation (ER) and internal rotation (IR) in national elite badminton players. METHODS: Seven elite badminton players with asymptomatic shoulders aged 24 ± 4 (mean ± SD) from the Danish national badminton team were investigated. Shoulder AHD, isometric strength in ER and IR were bilaterally assessed with ultrasonography and a hand-held dynamometer (HHD). RESULTS: AHD was greater on the dominant vs. the nondominant side (p = 0.018). Moreover, IR strength was greater on the dominant side vs. the nondominant side (p = 0.041). Furthermore, AHD and ER strength were highly correlated on the dominant side (p = 0.007, r = 0.900). A correlation was also shown between AHD and the ER/IR strength ratio on the dominant side (p = 0.033, r = 0.793). CONCLUSION: This preliminary study demonstrates that shoulder ER strength is strongly associated with AHD size, largely reflecting supraspinatus tendon-muscle hypertrophy as a result of sport-specific adaptation in national elite badminton players with asymptomatic shoulders. These novel data also suggest that habitual loading of the shoulder improves the supraspinatus tendon size, which may lower the mechanical stress and potentially reduce the risk of injury. This warrants strengthening the shoulder external rotators as a potential strategy to reduce the risk of future shoulder injury.

Magnetic Resonance T2 * Is Increased in Patients With Early-Stage Achilles and Patellar Tendinopathy.

BACKGROUND: T2 * mapping has proven useful in tendon research and may have the ability to detect subtle changes at an early stage of tendinopathy. PURPOSE: To investigate the difference in T2 * between patients with early tendinopathy and healthy controls, and to investigate the relationship between T2 * and clinical outcomes, tendon size, and mechanical properties. STUDY TYPE: Prospective cross-sectional. SUBJECTS: Sixty-five patients with early tendinopathy and 25 healthy controls. FIELD STRENGTH/SEQUENCE: Three Tesla, ultrashort time to echo magnetic resonance imaging. ASSESSMENT: Tendon T2 * was quantified using a monoexponential fitting algorithm. Clinical symptoms were evaluated using the Victorian Institute of Sports Assessment-Achilles/Patella (VISA-A/VISA-P). In vivo mechanical properties were measured using an ultrasound-based method that determined force and deformation simultaneously in tendons of patellar tendinopathy patients. STATISTICAL TESTS: A generalized linear model adjusted for age was applied to investigate the difference between patients and controls. In the two patient groups, linear regressions were applied to investigate the association between T2 * and tendon size, clinical outcomes, and biomechanical properties. RESULTS: There was a significant difference in T2 * between patients and healthy controls (204.8 [95% CI: 44.5-365.0] µsec, P < 0.05). There was a positive correlation between tendon size and T2 * for both Achilles (r = 0.72; P < 0.05) and patellar tendons (r = 0.53; P < 0.05). There was no significant correlation between VISA-A and T2 * (r = -0.2; P = 0.17) or VISA-P and T2 * (r = -0.5; P = 0.0504). Lastly, there was a negative correlation between modulus and T2 * (r = -0.51; P < 0.05). DATA CONCLUSIONS: T2 * mapping can detect subtle structural changes that translate to altered mechanical properties in early-phase tendinopathy. However, T2 * did not correlate with clinical scores in patients with early-phase Achilles and patellar tendinopathy. Thus, T2 * mapping may serve as a tool for early detection of structural changes in tendinopathy but does not necessarily describe the clinical severity of disease. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

The Reliability of the Segmental Assessment of Trunk Control (SATCo) in Children with Cerebral Palsy.

AIMS: To assess the live-versus-video, intrarater interday and interrater interday reliability of the test Segmental Assessment of Trunk Control (SATCo), which seeks to estimate the degree of sitting trunk control in children with cerebral palsy (CP). METHOD: Thirty-one children with CP between 9 months and 16 years of age (22 males, mean age 8y 10mo [SD 3y 5mo], Gross Motor Function Classification System level I [n = 13], II [n = 4], III [n = 4], IV [n = 3], and V [n = 7]) were included. Children were tested twice by two raters and tests were video recorded. Wilcoxon Signed-Rank Test, ICC [2,1] and a descriptive measure for absolute reliability were applied. RESULTS: No systematic differences were found between live-versus-video, between raters or days (p > 0.05) except for one analysis. All ICC values were excellent (ICC ≥ 0.9) except for one analysis for which it was good (ICC = 0.73). Complete agreement between scores was seen in 75% of all cases while 22% differed by one segmental level. Only 3% showed disagreement above one segmental level. CONCLUSIONS: SATCo is a clinically applicable assessment tool. Relative reliability is excellent and absolute agreement is good. Modifications regarding testing method could potentially improve the reliability and the value of the test in research and in clinical practice.

Characterising the proximal patellar tendon attachment and its relationship to skeletal maturity in adolescent ballet dancers.

BACKGROUND: It is unknown how and when the proximal attachment of the patellar tendon matures; puberty may be key in ensuring normal tendon formation. The aim of this study was to investigate the features of the proximal patellar tendon attachment at different stages of skeletal maturity, to help gain an understanding of how and when the tendon attachment matures. METHODS: Sixty adolescent elite ballet students (ages 11-18) and eight mature adults participated. Peak height velocity (PHV) estimated skeletal maturity. Ultrasound tissue characterisation (UTC) scan was taken of the left knee and analysed for stability of echopattern. An image-based grading scale for greyscale ultrasound was developed to describe the tendon appearance. Anterior-posterior thickness was measured at the inferior pole of the patella, 1 and 2 centimetres distally. Outcomes were compared with skeletal maturity. RESULTS: Mid-portion patellar tendon thickness increased with skeletal maturity (p=0.001 at 1 cm and p=0.007 at 2 cm). There was more variance in structural appearance (greyscale classification and UTC echopattern) in pre and peri-PHV participants. Tendon attachment one-year post PHV appeared similar to mature tendons. CONCLUSIONS: Early adolescence was associated with highly variable tendon appearance, whereas the tendon appeared mature after PHV. Adolescence may be a critical time for the formation of normal tendon attachment. LEVEL OF EVIDENCE: IIb individual cohort study.

Muscle power is an important measure to detect deficits in muscle function in hip osteoarthritis: a cross-sectional study.

PURPOSE: To investigate between-leg differences in hip and thigh muscle strength and leg extensor power in patients with unilateral hip osteoarthritis. Further, to compare between-leg differences in knee extensor strength and leg extensor power between patients and healthy peers. METHODS: Seventy-two patients (60-87 years) with radiographic and symptomatic hip osteoarthritis not awaiting hip replacement and 35 healthy peers (63-82 years) were included. Hip and thigh muscle strength and leg extensor power were measured in patients and knee extensor strength and leg extensor power in healthy. RESULTS: The symptomatic extremity in patients was significantly (p < 0.05, paired t-test) weaker compared with the non-symptomatic extremity for five hip muscles (8-17%), knee extensors (11%) and leg extensor power (19%). Healthy older adults had asymmetry in knee extensor strength (6%, p < 0.05) comparable to that found in patients, but had no asymmetry in leg extensor power. CONCLUSIONS: Patients had generalized weakening of the affected lower extremity and numerically the largest asymmetry was evident for leg extensor power. In contrast, healthy peers had no asymmetry in leg extensor power. These results indicate that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with hip osteoarthritis. Implications for Rehabilitation Even in patients with mild symptoms not awaiting hip replacement a generalized muscle weakening of the symptomatic lower extremity seems to be present. Between-leg differences in leg extensor power (force × velocity) appears to be relatively large (19%) in patients with unilateral hip osteoarthritis in contrast to healthy peers who show no asymmetry. Compared to muscle strength the relationship between functional performance and leg extensor power seems to be stronger, and more strongly related to power of the symptomatic lower extremity. Our results indicate that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with mild symptoms not awaiting hip replacement.

Human Achilles tendon glycation and function in diabetes.

Diabetic patients have an increased risk of foot ulcers, and glycation of collagen may increase tissue stiffness. We hypothesized that the level of glycemic control (glycation) may affect Achilles tendon stiffness, which can influence gait pattern. We therefore investigated the relationship between collagen glycation, Achilles tendon stiffness parameters, and plantar pressure in poorly (n = 22) and well (n = 22) controlled diabetic patients, including healthy age-matched (45-70 yr) controls (n = 11). There were no differences in any of the outcome parameters (collagen cross-linking or tendon stiffness) between patients with well-controlled and poorly controlled diabetes. The overall effect of diabetes was explored by collapsing the diabetes groups (DB) compared with the controls. Skin collagen cross-linking lysylpyridinoline, hydroxylysylpyridinoline (136%, 80%, P < 0.01) and pentosidine concentrations (55%, P < 0.05) were markedly greater in DB. Furthermore, Achilles tendon material stiffness was higher in DB (54%, P < 0.01). Notably, DB also demonstrated higher forefoot/rearfoot peak-plantar-pressure ratio (33%, P < 0.01). Overall, Achilles tendon material stiffness and skin connective tissue cross-linking were greater in diabetic patients compared with controls. The higher foot pressure indicates that material stiffness of tendon and other tissue (e.g., skin and joint capsule) may influence foot gait. The difference in foot pressure distribution may contribute to the development of foot ulcers in diabetic patients.

Functional adaptation of tendon and skeletal muscle to resistance training in three patients with genetically verified classic Ehlers Danlos Syndrome.

BACKGROUND: tendon and skeletal muscle function adapts to physical training of resistive nature, but it is unknown to what extent persons with genetically altered connective tissue - who have a higher than normal tendon extensibility - will obtain any effect upon their tendon and muscle when undergoing muscle strength training. We investigated patients with classical Ehlers Danlos Syndrome (EDS) (collagen type V defect) who display articular hypermobility, skin extensibility and tissue fragility. METHODS: subjects underwent strength training 3 times a week for 4 months and were tested before and after intervention in regards to muscle strength, tendon mechanical properties, and muscle function. RESULTS: three subjects completed the scheduled 48 sessions and had no major adverse events. Mean isometric leg extension force and leg extensor power both increased by 8 and 11% respectively (358 to 397 N, and 117 to 123 W). The tendon stiffness was tested and an average increase in response to physical training, from 1795 to 2519 N/mm was found. On average, the training loads both in upper and lower body exercises increased by around 30% over the training period. When testing balance, the average sway-area of the participants decreased by 26% (0.144 to 0.108 m(2)). On the subscale of CIS20 the participants lowered their average subjective fatigue score from 33 to 25. CONCLUSION: in this small pilot study, heavy resistance training was both feasible and effective in classic Ehlers Danlos patients, and the results indicated that both tendon and skeletal muscle properties can be improved also in this patient group when they are subjected to resistance training.

Low tendon stiffness and abnormal ultrastructure distinguish classic Ehlers-Danlos syndrome from benign joint hypermobility syndrome in patients.

There is a clinical overlap between classic Ehlers-Danlos syndrome (cEDS) and benign joint hypermobility syndrome (BJHS), with hypermobility as the main symptom. The purpose of this study was to investigate the role of type V collagen mutations and tendon pathology in these 2 syndromes. In patients (cEDS, n=7; BJHS, n=8) and controls (Ctrl, n=8), we measured patellar tendon ultrastructure (transmission electron microscopy), dimensions (magnetic resonance imaging), and biomechanical properties (force and ultrasonographic measurements during a ramped isometric knee extension). Mutation analyses (COL5A1 and COL5A2) were performed in the patients. COL5A1 mutations were found in 3 of 4 of the patients with cEDS. Patellar tendon dimensions were similar between the groups, but large, irregular collagen fibrils were in 4 of 5 patients with cEDS. In the cEDS group, tendon stiffness and Young's modulus were reduced to ∼50% of that in BJHS and Ctrl groups (P<0.05). The nonhypermobile, healthy controls were matched with the patients in age, sex, body weight, and physical activity, to compare outcomes. COL5A1 mutations led to structural tendon pathology and low tendon stiffness in cEDS, explaining the patients' hypermobility, whereas no tendon pathology was found that explained the hypermobility in BJHS.

Lack of tissue renewal in human adult Achilles tendon is revealed by nuclear bomb (14)C.

Tendons are often injured and heal poorly. Whether this is caused by a slow tissue turnover is unknown, since existing data provide diverging estimates of tendon protein half-life that range from 2 mo to 200 yr. With the purpose of determining life-long turnover of human tendon tissue, we used the (14)C bomb-pulse method. This method takes advantage of the dramatic increase in atmospheric levels of (14)C, produced by nuclear bomb tests in 1955-1963, which is reflected in all living organisms. Levels of (14)C were measured in 28 forensic samples of Achilles tendon core and 4 skeletal muscle samples (donor birth years 1945-1983) with accelerator mass spectrometry (AMS) and compared to known atmospheric levels to estimate tissue turnover. We found that Achilles tendon tissue retained levels of (14)C corresponding to atmospheric levels several decades before tissue sampling, demonstrating a very limited tissue turnover. The tendon concentrations of (14)C approximately reflected the atmospheric levels present during the first 17 yr of life, indicating that the tendon core is formed during height growth and is essentially not renewed thereafter. In contrast, (14)C levels in muscle indicated continuous turnover. Our observation provides a fundamental premise for understanding tendon function and pathology, and likely explains the poor regenerative capacity of tendon tissue.