Ultrasound characteristics of the patellar and quadriceps tendons among young elite athletes

Long-term Prognosis of Patellar Tendinopathy (Jumper's Knee) in Young, Elite Volleyball Players: Tendon Changes 11 Years After Baseline

BACKGROUND

The long-term prognosis of jumper's knee and whether structural changes in the patellar tendon persist is unknown.

PURPOSE

To investigate whether limitations in knee function and structural changes persisted beyond the athletic career of young elite volleyball players.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Volleyball players (mean ± SD age, 18 ± 0.8 years) enrolled in 2006-2011 in a prospective cohort study were invited in 2020-2022 to a follow-up study. Participants rated their knee function with the Victorian Institute of Sport Assessment-Patellar Tendon (VISA-P) score (baseline and follow-up) and the International Knee Documentation Committee (IKDC) score (follow-up) and reported if jumper's knee had influenced their decision to retire from sport. Tendon thickness and structural changes were assessed with ultrasound (baseline) and magnetic resonance imaging (MRI) (follow-up) of both patellar tendons.

RESULTS

We included 138 of 143 former athletes (97%) 11.4 ± 1.6 years after their baseline examination. At baseline, 37 persons (52 knees) had developed jumper's knee. At follow-up, participants reported lower knee function scores in knees diagnosed with jumper's knee at baseline than healthy knees (VISA-P scores: jumper's knee, 81 [95% CI, 70-92]; healthy, 90 [95% CI, 86-94]; P < .001; IKDC scores: jumper's knee, 82 [95% CI, 75-89]; healthy, 92 [95% CI, 91-95]; P < .001). Jumper's knee problems directly caused 7 of the 37 athletes (19%) with jumper's knee at baseline to retire from competitive volleyball. Of the 138 players included, 97 (70%) completed a bilateral MRI examination (194 knees). At follow-up, 38 of the 54 abnormal tendons (70%) had no structural changes (P < .001 vs baseline) while 22 of the 140 normal tendons (16%) had developed structural changes. Clinical symptoms were not correlated with tendon structure at follow-up (VISA-P scores for normal tendons: 85 [95% CI, 73-87]; abnormal: 89 [95% CI, 85-92]; P = .48).

CONCLUSION

Jumper's knee is not a self-limiting condition; volleyball players who had developed jumper's knee during adolescence reported persistent reductions in knee function 11 years later, leading one-fifth to retire from competitive volleyball. Although approximately 70% of tendons with structural changes at baseline were normal at follow-up, there was no clear relationship between structure and function.

Clinical and Imaging Outcomes Over 12 Weeks in Elite Athletes With Early-Stage Tendinopathy

Knowledge of how to treat chronic tendinopathy has advanced in recent years, but the treatment of early tendinopathy is not well understood. The main purpose of this prospective observational study was to investigate if changes occur in clinical and imaging outcomes over 12 weeks in elite athletes with recent debut of tendinopathy. Sixty-five elite adult athletes (24 ± 5 years) with early Achilles or patellar tendinopathy (symptoms < 3 months) were examined at baseline and after 12 weeks. Patients were divided into groups based on the duration of symptoms at the time of inclusion: (T1): 0-1 month, (T2): 1-2 months, or (T3): 2-3 months. Pain-guided activity modification was the only intervention. We assessed the following clinical outcomes: Questionnaires (Victorian Institute of Sports Assessment (VISA)) and pain scores (0-10 numeric rating scale, NRS), structural outcomes from ultrasonography: Thickness, echogenicity, and Doppler flow, and from magnetic resonance imaging: Cross-sectional area (CSA), thickness and length. Tendinopathic Achilles and patellar tendons displayed no significant differences on imaging tendon structural outcomes between T1 (n = 19), T2 (n = 23), and T3 (n = 20) at baseline or after 12 weeks, with one exception: Patellar tendons in T1 were thicker than T2 and T3 at baseline. Although athletes improved clinically on VISA and most NRS scores after 12 weeks, affected tendons with greater thickness, CSA and Doppler flow than contralateral tendons at baseline remained unchanged after 12 weeks. In conclusion, these data suggest that early tendinopathy in elite athletes can improve clinically after 12 weeks while morphology remains unchanged.

Tendon structure, clinical tests, and pain during-loading in young female competitive gymnasts

To examine the relationship between Achilles-tendon (AT) and patellar-tendon (PT) structure, clinical-examination and tendon pain in young gymnasts; and, to explore the associations between these factors and age, maturation, and training-load. Two hundred and seventy-four female gymnasts (aged 12.1±1.9 yrs) were assessed for anthropometric measures, pubertal-stage, and training-load. They had clinical-tests (pain-on-palpation for AT and pain-on-palpation and Royal-London Hospital-Test for PT), were asked about tendon-pain during-loading and were assessed for tendon-structure. Gymnasts with positive clinical-tests (with and without pain during-loading) presented a significantly higher prevalence of disorganized AT and PT compared to gymnasts with negative clinical-tests (with and without pain during-loading) (p<0.05). A significant pubertyXpositive clinical-test interaction was found for disorganized PT structure, whereby a disorganized structure was more prevalent among post-pubertal gymnasts with positive clinical-tests compared to pre-pubertal participants with negative clinical-tests (F(1, 263)=9.436, p=0.002). In gymnasts with positive clinical-tests, significant correlations were found between disorganized AT and PT structures and age, and training-load (p<0.05). An increased prevalence of disorganized tendon structure (regardless of pain during-loading) was seen in participants with positive clinical-tests. This disorganized tendon-structure was found to be significantly related to increased age, post-pubertal stage, and higher training hours in gymnasts with positive clinical-tests.

The Intra-articular Tendinous Graft Diameter of 10-mm Bone-Patellar Tendon-Bone Autografts in Adolescent Patients: An MRI Analysis of 100 Patients

Background

Bone-patellar tendon-bone (BPTB) autograft size may be one modifiable predictor of anterior cruciate ligament (ACL) reconstruction postoperative success, as smaller graft diameter has been associated with higher rates of rupture requiring revision. However, measuring the true intra-articular tendinous graft diameter of the soft tissue portion of a BPTB graft with standard intraoperative methods is difficult while keeping the graft intact.

Purpose/Hypothesis

The purpose of the study was to use 3-dimensional magnetic resonance imaging (MRI) measurements to determine the cross-sectional area of the soft tissue, tendinous portion of a standard BPTB autograft with 10-mm diameter bone plugs, and, by calculation, the collagen graft size (ie, graft diameter), as would typically be reported in ACL reconstruction studies that consider soft tissue graft size. It was hypothesized that the calculated collagen graft diameter of 10-mm BPTB autografts would be significantly smaller than 10 mm.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 100 patients (10 girls and 10 boys at each age from 13 to 17 years) who underwent a knee MRI at a single academic orthopaedic center without documented extensor mechanism pathology were identified. The central 10-mm width of the patellar tendon that would be harvested for BPTB autograft was measured. The region of interest area tool was then used to measure the cross-sectional area of a 10-mm BPTB graft with subsequent soft tissue autograft diameter calculation.

Results

The mean calculated tendinous graft diameter of a 10 mm-wide BPTB graft was 6.3 ± 0.5 mm and was significantly smaller than a 10-mm reference (P≤ .001). There was no significant association between age and cross-sectional area or graft diameter.

Conclusion

Modern 3-dimensional imaging-based measurement techniques demonstrated that the true intra-articular tendinous soft tissue portion of 10-mm BPTB autografts shows substantial variation and is significantly smaller in diameter than the tunnels typically reamed to accommodate the bone plug portions of these grafts. Moreover, as graft size is a predictor of rupture rate, preoperative MRI-based evaluation may be an important tool when considering BPTB autograft for ACL reconstruction. Future comparative clinical research utilizing graft size as a study variable should consider quantifying and utilizing the diameter of the soft tissue component of BPTB autografts.

Diagnostic Value of Superb Microvascular Imaging of the Rotator Cuff Interval for the Early Diagnosis of Frozen Shoulder

Purpose

To explore the early diagnostic value of superb microvascular imaging (SMI) features within the rotator cuff gap for frozen shoulder.

Patients and Methods

This prospective study enrolled patients with acute early-stage frozen shoulder seeking treatment at Zhabei Central Hospital in Jing'an District, Shanghai, between July 2021 and December 2022 were enrolled in this study. Healthy controls were collected in a 1:1 ratio from the same hospital's physical examination center. All participants underwent SMI and power Doppler ultrasound (PDUS) of the rotator cuff gap.

Results

The study included 79 patients with frozen shoulder and 77 healthy controls. Compared with the healthy control group, the patient group had a higher proportion of hypoechoic rotator cuff gap (81.0% vs 48.1%, P<0.001), a thicker coracohumeral ligament (2.60±1.01 vs 2.03±0.97, P<0.001), a thicker glenohumeral joint capsule (3.10±0.99 vs 2.46±1.17, P<0.001), and elevated blood grading using SMI (P<0.001) and PDUS (P=0.014). The highest area under the curve (AUC) was observed for SMI blood flow grading (AUC=0.824, 95% CI: 0.755-0.880, P<0.001), resulting in 82% sensitivity and 77% specificity when using a cutoff of 1. SMI blood flow grading was associated with external rotation <30° (P=0.007) and abduction <30° (P=0.013) but not with internal rotation <30° (P=0.630) or flexion <30° (P=0.562).

Conclusion

The grading of SMI blood flow may emerge as a valuable predictive indicator for the early stages of frozen shoulder. This simple ultrasound technique holds the potential to enhance the diagnostic process, enabling early initiation of treatment and potentially improving patient outcomes.

Differences in Achilles tendon mechanical properties between professional ballet dancers and collegiate athletes utilizing shear wave elastography

PURPOSE

To report normative stiffness parameters obtained using shear wave elastography in dorsiflexion from the Achilles tendons in asymptomatic professional ballet dancers and compare them with college-level athletes.

METHODS

An Institutional Review Board (IRB)-approved study consists of 28 professional ballet dancers and 64 asymptomatic collegiate athletes. The athletes were further subdivided into runner and non-runner disciplines. Shear wave elastography (SWE) measurements were made in maximum ankle dorsiflexion position.

RESULTS AND DISCUSSION

Forty-eight (52%) males and 44 (48%) females were examined with an overall mean age of 22.2 (± 3.8 years). There were no significant SWE differences between dominant and non-dominant legs in both groups and comparing spin vs. non-spin leg of ballet dancers (p > 0.05). Ballet dancers had significantly higher short-axis velocity values than runners and non-runners (2.34 m/s increase and 2.79 m/s increase, respectively, p < 0.001). Long-axis velocity was significantly higher in ballet dancers compared to non-runners (by 0.80 m/s, p < 0.001), but was not different between ballet dancers and runners (p > 0.05). Short-axis modulus was significantly higher in dancers compared to runners and non-runners (by 135.2 kPa and 159.2 kPa, respectively, p < 0.001). Long-axis modulus (LAM) was not significantly different in ballet dancers when compared to runners.

CONCLUSION

Asymptomatic professional ballet dancers exhibit greater short-axis tendon stiffness compared to athletes and greater long-axis tendon stiffness compared to non-runners but similar to runners. The functional benefit from elevated short-axis stiffness in dancers is not clear but may be related to greater axial loading and adaptations of the tendon matrix.

Ultrasonographic Evaluation of the Patellar Tendon in Cyclists, Volleyball Players, and Non-Practitioners of Sports-The Influence of Gender, Age, Height, Dominant Limb, and Level of Physical Activity

This study was based on the ultrasound evaluation of the patellar tendon dimensions in the anteroposterior and transversal approaches in sports practitioners (cyclists and volleyball players) and non-sports practitioners. Relationships between the patellar tendon length, width, and thickness with gender, age, height, the dominant limb, and level of physical activity were evaluated. The samples included cyclists, volleyball players, and non-sports practitioners between 15 and 25 years old. Individuals were positioned supine with 30 degrees of knee flexion for bilateral measurements. Sports practitioners presented with an increased patellar tendon length and thickness. There were significant differences bilaterally between sports and non-sports practitioners (p < 0.003). The three dimensions of the patellar tendon of both limbs presented correlations with the male gender (0.336 < r < 0.601), and values of moderate-to-strong intensity in the length of the patellar tendon was directly proportional to height (0.520 < r < 0.601). There was a significant difference between the patellar tendon width and age (p < 0.025). Regarding the level of physical activity, significant differences were found between low and high levels in the three dimensions bilaterally (p < 0.004). The study results indicate that gender, age, height, and level of physical activity impact patellar tendon dimensions. However, there are no associations with the dominant limb.

Sonographic Assessment of Asymptomatic Patellar and Achilles Tendons to Predict Future Pain: A Systematic Review and Meta-analysis

OBJECTIVE

Patients with clinical tendinopathy often demonstrate significant abnormalities with ultrasound (US) imaging. Tendon abnormalities likely precede pain in these patients. The purpose of this review was to systematically evaluate the available literature regarding the utility of US imaging as a method to predict Achilles and patellar tendon pain.

DESIGN

Systematic review and meta-analysis. Inclusion criteria were as follows: prospective studies of Achilles and patellar tendon pain development with baseline US measurements, follow-up clinical measurements, and English-language studies published after 2000. Exclusion criteria were prior rupture or surgery and presence of rheumatologic disorder.

SETTING

N/A.

PATIENTS

Athletes without Achilles or patellar tendon pain at baseline.

INTERVENTIONS

N/A.

MAIN OUTCOME MEASURES

Risk ratios (RRs) were identified for the development of pain in those with Achilles or patellar tendon sonographic abnormalities.

RESULTS

This review of 16 studies included 810 Achilles and 1156 patellar tendons from a variety of sports and demonstrated that the RR for pain development from abnormal Patellar and Achilles tendons was 6.07 [95% confidence interval (CI), 2.88-12.81; P < 0.001] and 3.96 [95% CI, 2.21-7.09; P < 0.001], respectively. The positive and negative predictive values of an abnormal US finding were 27.2% and 92.0% for the Achilles tendon and 27.2% and 93.5% for the patellar tendon, respectively.

CONCLUSIONS

This systematic review and meta-analysis identified that the use of asymptomatic US scanning of the Achilles or patellar tendon has a low positive predictive value but a high negative predictive value for the future development of pain.

Determination of differences in ultrasound parameters for patellar tendons in males with unilateral patellar tendinopathy-An ancillary analysis of data from two randomized controlled trials

PURPOSE

To investigate power Doppler (PD) activity and tendon structure (between the injured and contralateral limb) in patients with unilateral patellar tendinopathy (PT) using ultrasonography (US). Secondly, the aim was to determine the intra-rater reliability of the PD activity and tendon structure.

METHODS

This study analyzed US baseline data from 57 male participants with symptomatic unilateral PT who had been enrolled in one of two randomized clinical trials. Data were analyzed to examine if systematic differences existed between injured and contralateral limbs using Fiji ImageJ.

RESULTS

The PD activity of the symptomatic tendon was larger 25.6 (Q1 = 14.9; Q3 = 41.6) mm2 than the asymptomatic 0 (Q1 = 0.0; Q3 = 0.0) mm2 (p < 0.001). There was a significantly greater tendon thickness at the proximal (2.5 mm 95% CI [2.0; 3.0]), mid (0.8 mm 95% CI [0.5; 1.1]), and distal (0.2 mm 95% CI [0.1; 0.4]) part of the tendon for the symptomatic compared to the asymptomatic tendon. Intra-rater reliability for PD activity and tendon structure ranged from moderate-to-excellent (0.74; 0.99).

CONCLUSION

These results provide mean estimates for tendon thickness of symptomatic and asymptomatic tendons, that can be used for clinicians to reliably estimate pathological tendon thickness.

Evaluation of Achilles Tendon Stiffness as Measured by Shear Wave Elastography in Female College Athletes Compared With Nonathletes

BACKGROUND

We sought to utilize a noninvasive technology to assess the effects of activity on Achilles tendon stiffness and define baseline Achilles tendon stiffness in female college athletes compared with nonathletes using tendon shear wave velocity as a marker for tendon stiffness.

HYPOTHESIS

Training status and exercise may affect Achilles tendon stiffness.

STUDY DESIGN

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 32 college-age female athletes were prospectively enrolled (n = 17 varsity athletes and n = 15 nonathletes). Demographic characteristics, activity level, and previous injuries were recorded. Sonographic shear wave elastography (SWE) was used to assess Achilles tendon shear wave velocity bilaterally for all subjects, both at baseline and after 2 minutes of exercise. Student t tests were used to compare the mean elastography measurements between participants stratified by athlete status and pre/postexercise stimulus. Analysis of variance (ANOVA) was used to compare the mean proximal, middle, and distal Achilles tendon elastography measurements.

RESULTS

As seen by a greater mean shear wave velocity (8.60 ± 1.58 m/s vs 8.25 ± 1.89 m/s; P = 0.02), athletes had stiffer tendons than nonathletes. Exercise stimulus decreased average tendon shear wave velocity (8.57 ± 1.74 m/s vs 8.28 ± 1.72 m/s; P = 0.05). Tendon shear wave velocity was greatest proximally and least distally with significant differences between each region (P < 0.001). In addition, there was a significant 2-way interaction between weekly training status and foot dominance (P = 0.01). Post hoc analysis showed that this result was due to differences in tendon shear wave velocity between the dominant and nondominant lower extremity in nonathletes (7.73 ± 2.00 m/s vs 8.76 ± 1.62 m/s; P < 0.001).

CONCLUSION

Female varsity collegiate athletes have higher baseline Achilles tendon stiffness as measured by SWE compared with nonathletes. Mean tendon stiffness varies based on Achilles measurement location. SWE is a quick, cost-effective, and noninvasive imaging modality that can be used to evaluate tendon stiffness and elasticity.

CLINICAL RELEVANCE

SWE is an efficient and noninvasive imaging modality that can evaluate dynamic tendon stiffness and elasticity. SWE may be helpful to assess injuries in female college athletes and may play a role in risk stratification or clinical follow-up. In theory, SWE could be used to identify athletes with increased elasticity as a marker for potential risk for rupture in this population.

Does the ultrasound imaging predict lower limb tendinopathy in athletes: a systematic review

BACKGROUND

To conduct a systematic review looking into the possibility of US imaging to anticipate and identify future patellar or Achilles tendinopathy symptoms.

METHODS

The studies that were taken into consideration for this review were prospective studies that employed baseline US imaging of the patellar OR Achilles tendons in asymptomatic patients and follow-up measures of pain and/or function. Two impartial reviewers evaluated the study's quality using the Critical Appraisal Skills Programme instrument.

RESULTS

Participants in the included studies in this review came from various sports. The systematic review revealed a link between baseline tendon abnormalities in the US and a higher chance of developing both patellar and Achilles tendinopathy as well as their future occurrence. Nine of the included studies examined the patellar tendon alone, eight the patellar and Achilles tendon together, and four the Achilles tendon exclusively. For both tendons, US administration is done in a largely consistent manner. The tendon abnormalities of tendon thickness, hypoechogenicity and vascularity at baseline were associated with an increased risk of both Achilles and patellar tendinopathy.

CONCLUSIONS

This systematic review shows that abnormal tendon structures seen by US in asymptomatic persons can predict the development of tendinopathy.

Patellar tendinopathy: an overview of prevalence, risk factors, screening, diagnosis, treatment and prevention

Patellar tendinopathy (PT), or jumper's knee, is an overuse injury that occurs in professional, as well as recreational, athletes. This condition is a noncontact injury, typically characterized by gradually increasing pain in the patellar tendon. It is prevalent in participants of several sports, but it occurs mostly in jumping sports. The diagnosis of PT is primarily clinical; however, imaging techniques can be useful as well. Risk factors differ between sexes, playing conditions, the kind of sport, playing level and personal characteristics. Screening is an essential tool to assess PT. This condition affects athletic performance and often persists for years. The use of preventative methods is imperative because of the persistence of this condition, especially in elite athletes who sometimes end their career after long and failed treatments. There are a wide variety of treatment and rehabilitation options available, the majority of which are non-operative, such as eccentric exercises, cryotherapy, platelet-rich plasma (PRP) injections, and anti-inflammatory strategies. If conservative treatment fails, surgery is the next most preferable step. Even though there are many surgical treatment methods, there is no clear evidence on what is the most effective approach to address PT. Taking this into consideration, as well as the extent of this clinical entity, novel therapeutic techniques, as well as screening and prevention methods, are expected to emerge in the near future.

Quadriceps strength, patellar tendon quality, relative load exposure, and knee symptoms in male athletes before the anterior cruciate ligament reconstruction

Introduction

Anterior cruciate ligament (ACL) injuries cause knee instability, knee pain, weight-bearing adjustments, and functional deficits but their association to patellar tendon quality is unknown. Our purpose was to investigate quadriceps strength, patellar tendon quality, relative load exposure, perceived knee stability, knee pain, extension angle, and time from ACL injury; in addition to examining their relative associations.

Methods

Injured and uninjured legs of 81 male athletes of different sports with a unilateral ACL injury (18-45 years) were examined. Participants reported location and intensity of knee pain and their perceived stability using a numerical rating scale (NRS 0-10). Strength was tested with an isokinetic device. Tendon quality was measured using ultrasound tissue characterization. Means ± standard deviation (SD) of perceived knee stability, knee extension angle, knee pain, isokinetic quadriceps strength in relation to body mass, proportion of echo-types (I-IV), tendon volume, and number of days from ACL injury to assessment are reported. Values of effect sizes (ES) and correlations (rs) were calculated.

Results

ACL injured leg demonstrated reduced reported knee stability (6.3 ± 2.5), decreased knee extension angle (-0.7 ± 3.1° vs. -2.7 ± 2.2°; ES = 0.7; P < 0.001), greater knee pain (NRS 3.1 ± 2.2 vs. 0.0 ± 0.1; ES = 2.0; P < 0.001), and 22% lower quadriceps strength (228.0 ± 65.0 vs. 291.2 ± 52.9 Nm/kg: ES = 1.2; P < 0.001) as compared to the uninjured leg. However, patellar tendons in both legs displayed similar quality. Quadriceps strength was associated with stability (rs = -0.54; P < 0.001), pain (rs = -0.47; P < 0.001), extension angle (rs = -0.39; P < 0.001), and relative load exposure (rs = -0.34; P < 0.004). Echo-types distribution was beneficially associated with time from ACL injury (rs range: -0.20/ -0.32; P < 0.05).

Discussion

ACL injured athletes displayed knee pain, extension deficit, and weaker quadriceps in the injured leg. While there were no differences in patellar tendon quality between legs, longer time from ACL injury showed better tendon quality.

Achilles Tendon and Patellar Tendon Structure in Combat Soldiers Following Prevention Exercises

INTRODUCTION

Military training that increases physical stress on musculoskeletal morphology also increases the risk of orthopedic injuries. Somatosensory prevention programs that reduce stress and improve functionality could be beneficial for better organization of tendon structure. The aim of this study was to investigate the impact of a somatosensory prevention exercise on the tendon structure (percentage of echo-type fibers; A-P and M-L diameters and cross-sectional area) of the Achilles tendon and patellar tendon among combat soldiers.

MATERIALS AND METHODS

These tendons of male Infantry soldiers aged 18-21 were screened before and after a 14-week training course. The intervention group, who performed preventative exercises, included 108 soldiers (BMI = 23.85 ± 2.76), while the control group, who participated in the same military course without these exercises, included 98 soldiers (BMI = 24.26 ± 4.03). Ultrasound scanning for tendon structure included percent of echo-type I-IV fibers, A-P diameter, M-L diameter, and cross-sectional area parameters.

RESULTS

Time by group interaction was found for echo-type I and II in both tendons. No significant differences were found between the two groups in the pretesting percentage of echo-type IV fibers of the Achilles tendon (P = .522), in echo-type III fibers of the Achilles tendon (P = .833), and echo-type IV fibers of the patellar tendon (P = .162). Greater pre-post differences in echo-type III and IV fibers were found in the control group compared with the intervention group for both the Achilles tendon (P = .021, P = .002) and the patellar tendon (P < .001, P < .001).

CONCLUSION

Increased damaged fibers (echo-type III and IV) of both tendons were found among the control group, yet not among soldiers who performed prevention exercises.

Proximal patellar tendon abnormalities on ultrasound can develop in male adolescent basketball players: A longitudinal study

INTRODUCTION

Adolescent patellar tendinopathy is reported but the pubertal-stage of onset of abnormal tendon structure has not been investigated with grayscale ultrasound.

AIMS

To investigate abnormal tendon structure using grayscale ultrasound and its association with pubertal-stage and pain.

METHODS

Forty-three male basketball players aged 13.7 years (SD 1.0) had patellar tendon ultrasound scans every 6 months for 2.5 years. Pubertal-stage (peak height velocity) was calculated using the Mirwauld equation. Tendon thickness, hypoechogenicity and pain during single leg decline squat (SLDS) were recorded. Tendons were classified: hypoechoic, normal or immature.

RESULTS

Two tendons were hypoechoic at baseline. Six developed hypoechogenicity over 2.5 years (eight tendons [9%], six participants [14%]), all in peri and post-PHV players. Twenty-six tendons (17 participants) were classified as immature during the study. Hypoechoic tendons were thicker (5.3 mm SD 1.2) than normal (3.9 mm SD 0.7) tendons (p < 0.001). There was no difference in the proportion of participants reporting pain during SLDS in the hypoechoic (N = 3) and normal (N = 11) groups (p = 0.33), or in hypoechoic tendon thickness between those reporting pain (6.5 mm, SD 1.7) or not (5.2 mm, SD 0.9, p = 0.17).

DISCUSSION

This study using grayscale ultrasound found that basketball players with hypoechogenicity were peri or post-PHV. Abnormal structure was not always associated with pain.

Achilles and patellar tendon structure following a prevention program in male combat soldiers

OBJECTIVES

The aims of the study were to compare the prevalence of soldiers with musculoskeletal symptoms between soldiers that participated in a prevention program (INT) and a control group (CONT); and, to assess whether 'high risk' for a symptom indicator [participants with patellar tendon (PT) echo-type III+IV >10% or Achilles tendon (AT) echo-type III >8.5%] applies when a prevention intervention is used.

METHODS

Soldiers from two consecutive infantry commanders courses (year 1-CONT, n = 165; year 2-INT, n = 196) were examined pre-course for AT and PT structure using ultrasound tissue characterization (UTC), and their musculoskeletal overuse symptoms were assessed and recorded by military physicians throughout the course. A prevention program was provided to the INT group (year 2) during the 14-week course.

RESULTS

No significant differences were found in the prevalence of soldiers with symptoms between the two groups [INT: 39 (19.9%), CONT: 40 (24.2%); p = .32]. Using the indicator at baseline, 20 soldiers (10.2%) were suggested to be at 'high risk.' Of those 20 soldiers, 17 actually had symptoms during the course (positive predictive value-85%). The prevalence of soldiers with a suggested 'high risk' according to our indicator who had no symptoms during the course was low (3/20, 15%). Twenty-two soldiers who had symptoms during the course had not been suggested to be at 'high risk' by our indicator.

CONCLUSION

Our intervention did not reduce the prevalence of soldiers with symptoms. Our 'high risk' pre-course, AT and PT structure indicator is valid and can be used as a screening tool to reduce the prevalence of symptoms in combat soldiers; with the caution that soldiers that were not identified by the indicator, might also have symptoms along the course.

Sonographic Screening of Distance Runners for the Development of Future Achilles and Patellar Tendon Pain

OBJECTIVE

The 2 primary aims of this study were to identify ultrasonographic tendon abnormalities in asymptomatic runners and to examine the likelihood of developing pain in runners with ultrasound abnormalities compared with those without abnormalities.

DESIGN

Longitudinal, prospective cohort study.

SETTING

2019 Salt Lake City Marathon.

PARTICIPANTS

Recreational half-marathon and full-marathon runners.

ASSESSMENT OF RISK FACTORS

The Achilles and patellar tendons of asymptomatic runners were examined with ultrasound imaging before a running event. Runners were monitored for self-reported outcomes of pain in the examined tendons at 1, 3, 6, and 12 months after the event.

MAIN OUTCOME MEASURES

Development of pain based on the presence of asymptomatic tendon abnormalities.

RESULTS

One hundred thirty-eight runners (36.2 ± 12.0 years, 49.3% men, and 31.2% full-marathon runners) were included. Ultrasound abnormalities of the Achilles and patellar tendons were identified in 24.6% and 39.1% of the runners before the race, respectively. Ultrasound abnormalities were significantly associated with approximately a 3-fold increase [hazard ratio (HR) = 2.55, P = 0.004] in the hazard of developing pain in the Achilles tendon and patellar tendon (HR = 1.67, P = 0.042) over the year after the race. Positive and negative predictive values of developing pain over the year were 34.1% and 87.2%, respectively, for abnormal findings in the Achilles tendon, and 22.9% and 85.0%, respectively, for the patellar tendon.

CONCLUSIONS

The presence of ultrasonographic abnormalities is associated with increased development of pain in the Achilles and patellar tendons within 1 year of a marathon or half marathon.

Role of Shear-Wave Elastography in Achilles Tendon in Psoriatic Arthritis and Its Correlation with Disease Severity Score, Psoriasis Area and Severity Index

Purpose  The aim of this study was to compare accuracy of shear-wave elastography (SWE) with gray scale (GS) ultrasound and power Doppler (pD) for diagnosing Achilles tendinopathy in psoriatic patients with and without arthritis and correlation with achillodynia and disease severity score, psoriasis area and severity index (PASI).

Methods  A total of 100 Achilles tendons were evaluated where 56% were cases of psoriatic arthritis with achillodynia; 44% were controls of psoriasis without arthritis in this prospective study. Evaluation was done with GS, pD, SWE at proximal, mid, and distal third of the tendon. Qualitative (color maps) and quantitative data, elastic modulus, kilopascal (kPa), were generated. Pearson's correlation was done to see association between kPa, PASI and clinical symptoms, achillodynia, scored using visual analog scale (VAS).

Results  Significant negative correlation was seen between duration of arthritis, VAS and PASI with SWE values with r  = −0.34, −0.47, and −0.41, respectively. SWE could identify abnormal tendons in 71/100 (71%) in the overall study, 53/56 (94.6%) in cases, and 18/44 (40.9%) in control. The statistical significance was set at p  ≤ 0.05. In comparison, conventional ultrasound, GS, and pD together could identify 13/56 (23.21%) in cases and no abnormal tendon was identified in the control group.

Conclusion  SWE is a reliable, noninvasive, and valuable tool to detect early tendinopathy and monitor progression of disease.

Concepts of Entheseal Pain

Pain is the main symptom in entheseal diseases (enthesopathies) despite a paucity of nerve endings in the enthesis itself. Eicosanoids, cytokines, and neuropeptides released during inflammation and repeated nonphysiologic mechanical challenge not only stimulate or sensitize primary afferent neurons present in structures adjacent to the enthesis, but also trigger a "neurovascular invasion" that allows the spreading of nerves and blood vessels into the enthesis. Nociceptive pseudounipolar neurons support this process by releasing neurotransmitters from peripheral endings that induce neovascularization and peripheral pain sensitization. This process may explain the frequently observed dissociation between subjective symptoms such as pain and the structural findings on imaging in entheseal disease.

Ultrasound imaging of patellar tendon thickness in elite sprint track cyclists and elite soccer players: An intra-rater and inter-rater reliability study

The goal of our study was to investigate the relative and absolute intra-rater and inter-rater reliability of ultrasound assessment of patellar tendon (PT) thickness assessed over four locations, in track cyclists and soccer players. Fifteen male elite track cyclists and 15 male elite soccer players participated. Tendon thickness was measured over 4 locations placed at 5-10-15-20 mm inferior to the apex of the patella by two experienced examiners. Each examiner took two US images for the test measurements with a 10-min rest period. After a 30-min period, the subjects underwent a retest measurements that were also repeated 1-week after. A two-way analysis of variance revealed a significant group x location interaction on PT thickness for Examiner 1 (p = .001, η² = .81) and Examiner 2 (p = 0.001, η² = 0.78). Intra-rater reliability ranged from good to excellent (ICC_2,k ≥ 0.75), whereas inter-rater reliability was good (ICC_2,k ≥ 0.75) in both groups. Ultrasonographic assessment of PT was found to be a reliable method to assess tendon thickness. The middle location of the PT (corresponding to 15 and 20 mm) can be considered the most reliable spot to measure PT thickness. The PT thickness was larger among track cyclists than soccer players, with larger differences over the distal location (15 mm). Ultrasonographic assessment of PT was found to be a reliable method to assess tendon thickness. The middle location of the PT corresponding to 15 mm and 20 mm can be considered the most reliable area to measure PT thickness.

Knee Extensor Mechanism Tendinopathy: Evaluation, Treatment, and Prevention

ABSTRACT

Knee extensor mechanism tendinopathy, including patellar and quadriceps tendinopathy, is common among athletes and those involved in jumping sports. It is largely a clinical diagnosis that presents as anterior knee pain and stiffness with associated tenderness over the affected tendon. Imaging modalities, including ultrasound and/or magnetic resonance imaging, may be helpful with the diagnosis of difficult cases or in the planning of interventional procedures. Focused and structured rehabilitation using eccentric or heavy slow resistance exercise in conjunction with load management is important for recovery. Adjuvant therapies (e.g., injections or surgery) may be necessary in recalcitrant cases or those with insufficient response to rehabilitation efforts. Prevention strategies focus on improving biomechanics, landing mechanism and lower-extremity balance, flexibility, and strength.

The aging athlete

Aging athletes, those 60 years and older, are a growing population of mature, active individuals who value sports and exercise participation throughout their lifespan. Although recommendations for younger and masters athletes have been extrapolated to this population, there remains a paucity of specific guidelines, treatment algorithms, and considerations for aging athletes. The benefits of living an active lifestyle must be weighed against the risks for unique cardiovascular, metabolic, and musculoskeletal injuries requiring diagnostic and therapeutic interventions. In this article, we review the unique cardiovascular and muscular physiology of aging athletes and how it influences the risk of specific medical conditions. We also discuss general prevention and treatment strategies. Finally, we identify areas of future research priorities and emerging treatments.

CARDIOVASCULAR RESPONSE OF ATHLETES UNDER DIFFERENT TRAINING CONDITIONS

ABSTRACT Introduction: Improving cardiovascular function is one of the main training goals of many sports. Objective: To understand the characteristics of the cardiovascular response of athletes under different training conditions. Methods: Thirty male basketball students were enrolled. The subjects were divided into A and B groups according to their years of training, with 15 students in each group. Exercise fatigue tests were performed, starting at a low intensity and gradually increasing the load to a relatively high degree of fatigue. Results: The RMSSD value was 42.82±31.41ms in group A and 46.48±35.26ms in group B undera low fatigue state. The LF/HF value of the athletes in group A was 2.86±1.47 and the LF/HF value of the athletes in group B was 2.94±1.68. The RMSSD value was 40.78±31.17ms and 32.37±36.42ms for groups A and B, respectively, undera high fatigue state. Conclusions: Athletes with more years of training can mobilize more cardiac reserves to meet the increase in exercise load in a fatigue state and have better autonomic nervous regulation in the process of reaching a higher degree of fatigue state. Level of evidence II; Therapeutic studies - investigation of treatment results.

Shear wave elastography assessment and comparison study of the Achilles tendons in optimally conditioned asymptomatic young collegiate athletes

OBJECTIVE

To assess the functional parameters of the Achilles tendons among asymptomatic college level athletes using shear wave elastography (SWE) and to describe the relationship to athlete demographics and anthropometric lower extremity measurements.

MATERIAL AND METHODS

Sixty-five athletes were included in this IRB-approved study. SWE measurements were made on two tendon positions (neutral state and active maximum dorsiflexion) with two different probe orientations (longitudinal and transverse). Associations were assessed with BMI, tibial/foot length, type of sports, and resting/maximal dorsiflexion-plantar flexion angles.

RESULTS

Thirty-five (53.8%) males and 30 (46.2%) females with an overall mean age of 20.9 years (± 2.8), mean height of 176 cm (± 0.11), and mean weight of 74.1 kg (± 12) were studied. In the neutral state, the mean wave velocity of 7.5 m sec^-1 and the mean elastic modulus of 176.8 kPa were recorded. In active maximum dorsiflexion, the mean velocity was 8.3 m sec^-1 and mean elastic modulus was 199 kPa. On the transverse view, the mean velocity and elastic measurements were significantly lower (p = 0.0001). No significant differences in SWE parameters were seen between male and female athletes regardless of probe orientation (p < 0.05) with SWE values being higher in the running group vs non-running group (p < 0.05). In neutral state, longitudinal SWE measurements correlated with the tibia-foot length whereas transverse measurements correlated with the tendon diameter and ankle resting angle (ARA) (p < 0.005).

CONCLUSION

SWE can distinguish functional differences in Achilles tendon stiffness between athletes engaged in running-intensive sports compared with other athletes.

Ultrasound evaluation of the patellar tendon and Achilles tendon and its association with future pain in distance runners

Objectives: To examine whether asymptomatic ultrasonographic abnormalities in the Achilles and patellar tendons in runners are associated with an increased risk of pain development.Methods: This is a longitudinal, prospective cohort study with 139 runners recruited at a half and full marathon race. Ultrasound examination of the Achilles and patellar tendons was performed bilaterally the day prior to the race. Self-reported injury data were collected at 1, 3, 6 and 12 months. 104 (74.8%) runners were included in the data analysis.Results: Ultrasonographic tendon abnormalities were found in 24.1% of the Achilles and in 23.1% of the patellar tendons prior to the race. Runners with tendon abnormality were 2-3 times more likely to develop pain within 12 months than those without (relative risk = 3.14, p = 0.010 for Achilles; relative risk = 2.52, p = 0.008 for patellar tendon). After adjusting for gender, age, years of running, average miles per week of running over a year, and pre-race pain, runners with ultrasound abnormality were about 3 times (hazard ratio = 2.89, p = 0.039 for Achilles; hazard ratio = 2.73, p = 0.030 for patellar tendon) more likely to develop pain after the race. Tendon delamination was most strongly associated with pain in both the Achilles (relative risk = 6.00; p = 0.001) and patellar tendons (relative risk = 3.81; p = 0.001).Conclusions: Structural changes in asymptomatic tendons were found in almost 25% of runners. Presence of structural changes was associated with increased development of Achilles and patellar tendon pain within one year.

An Objective Measure of Patellar Tendon Thickness Based on Ultrasonography and MRI in University Athletes

Ultrasonography and MRI are used for imaging evaluation of patellar tendinopathy, and “thickening of the tendon” is known as one of the characteristic findings. However, there are no evidence-based quantitative criteria to help evaluate this phenomenon. The purpose of this study was to investigate an objective measure of patellar tendon thickness. Patellar tendon thickness was evaluated in 65 elite university athletes using both ultrasonography and MRI. The relationship between tendon thickness and clinical patellar tendinopathy was investigated, and the cutoff value of the tendon thickness was calculated. Of the 129 knees included in the analysis, clinical patellar tendinopathy was found in 16 knees (12.4%). The proximal patellar tendon was significantly thicker in athletes with clinical patellar tendinopathy on both ultrasonography (8.3 mm vs. 5.1 mm; p < 0.001) and MRI (9.9 mm vs. 5.5 mm; p < 0.001). Setting the cutoff value to a thickness of >7.0 mm was an accurate predictor of clinical patellar tendinopathy (ultrasonography: sensitivity 81.3%, specificity 95.6%; MRI: sensitivity 100%, specificity 89.4%). Both ultrasonography and MRI measurement of the proximal patellar tendon thickness reflected the presence of clinical patellar tendinopathy. Defining “thickening of the patellar tendon” as thicker than 7.0 mm on both ultrasonography and MRI therefore has clinical significance.

Implementing Ultrasound Imaging for the Assessment of Muscle and Tendon Properties in Elite Sports: Practical Aspects, Methodological Considerations and Future Directions

Ultrasound (US) imaging has been widely used in both research and clinical settings to evaluate the morphological and mechanical properties of muscle and tendon. In elite sports scenarios, a regular assessment of such properties has great potential, namely for testing the response to training, detecting athletes at higher risks of injury, screening athletes for structural abnormalities related to current or future musculoskeletal complaints, and monitoring their return to sport after a musculoskeletal injury. However, several practical and methodological aspects of US techniques should be considered when applying this technology in the elite sports context. Therefore, this narrative review aims to (1) present the principal US measures and field of applications in the context of elite sports; (2) to discuss, from a methodological perspective, the strengths and shortcomings of US imaging for the assessment of muscle and tendon properties; and (3) to provide future directions for research and application.

Physical Activity and Investigation With Magnetic Resonance Imaging Partly Explain Variability in the Prevalence of Patellar Tendon Abnormalities: A Systematic Review With Meta-analysis of Imaging Studies in Asymptomatic Individuals

OBJECTIVE

To estimate the pooled prevalence of, and factors associated with, the presence of patellar tendon abnormalities observed on imaging in people without symptoms.

DESIGN

Systematic review with stratified meta-analysis and meta-regression.

LITERATURE SEARCH

We searched Embase, Scopus, MEDLINE, CINAHL, SPORTDiscus, and Web of Science from 1980 to August 2020.

STUDY SELECTION CRITERIA

We included studies that reported the prevalence of asymptomatic patellar tendon abnormalities on imaging. We excluded studies of participants with current tendon pain, a history of tendon pain, or other systemic conditions.

DATA SYNTHESIS

Stratification and meta-regression of studies based on study-level descriptive statistics (mean age, body mass index, proportion of female participants, physical activity participation, imaging modality) were performed using a random-effects model to account for between-study heterogeneity. Risk of bias was assessed using the modified Newcastle-Ottawa scale.

RESULTS

Meta-analysis of 64 studies (7125 limbs from 4616 participants) found significant between-study heterogeneity (I²≥90%, P<.01), which precluded a summary prevalence estimate. Heterogeneity was partially explained by studies that included participants who were physically active and studies that assessed tendon abnormalities using magnetic resonance imaging compared to ultrasound (P<.05). Mean age, body mass index, proportion of female participants, and sample size did not explain the remaining heterogeneity.

CONCLUSION

There was substantial variability in the reported prevalence of asymptomatic patellar tendon abnormalities. A clear and valid method is needed to assess and report the presence of patellar tendon abnormalities to increase research capacity and establish the clinical value of imaging the patellar tendon. J Orthop Sports Phys Ther 2021;51(5):216-231. Epub 28 Mar 2021. doi:10.2519/jospt.2021.10054.

Substantiating the Use of Ultrasound Tissue Characterization in the Analysis of Tendon Structure: A Systematic Review

OBJECTIVE

To determine the role of ultrasound tissue characterization (UTC) in predicting, diagnosing, and monitoring tendon structure and/or tendinopathy. In addition, this study aims to provide recommendations for standardized methodology of UTC administration and analysis.

DATA SOURCE

The PubMed, Embase, and Web of Science databases were searched (up to September 2018). All scientific literature concerning the use of UTC in assessing tendons was collected. The initial search resulted in a total of 1972 hits, and after screening by eligibility criteria, 27 articles were included.

RESULTS

In total, 18 investigating the Achilles tendon, 5 the patellar tendon, and 4 both Achilles and patellar tendons were included. The methods of UTC administration and analysis differed and were not uniform. The studies showed that the use of UTC to predict Achilles tendinopathy (AT) is inconclusive, but that a higher amount of tendon disorganization increases the risk of developing patellar tendinopathy (PT). In terms of diagnosis, UTC might provide additional information in AT cases. In addition, promising results were found for the use of UTC in both AT and PT in monitoring the effect of load or treatment on tendon structure.

CONCLUSION

More research regarding the use of UTC in predicting tendon pathology is required. Ultrasound tissue characterization seems useful as an adjunct diagnostic modality because it can be used to differentiate symptomatic from asymptomatic tendons. In addition, UTC is a promising device to be used to monitor changes in tendon structure in response to load or treatment. Moreover, we provide recommendations of a standardized protocol concerning the methods of UTC measurement and analysis.

Anterior knee pain after total knee arthroplasty: A multifactorial analysis

PURPOSE

Dissatisfaction and an impaired quality of life after total knee arthroplasty (TKA) is often associated with postsurgical anterior knee pain (AKP). The underlying pathological mechanisms are not yet fully understood. Therefore, a multifactorial approach encompassing clinical and radiological parameters seemed reasonable and promising to investigate postsurgical AKP.

METHODS

In this cross-sectional study, 25 patients without and 25 patients with postsurgical AKP after unilateral TKA were randomly recruited from a larger cohort of patients. Multiple clinical and radiological parameters-including real-time shear wave elastography (SWE) to measure the patellar and quadriceps tendon elasticity-were acquired and subsequently associated with AKP. For statistical analysis, SPSS (IBM, version 25) was used.

RESULTS

In total 50 participants (58.0% men, mean age 63.42 years, mean body mass index 29.75 kg/m²), having different prosthetic designs implanted, were included. Independently of key covariates, the strength of the quadriceps muscle (p = 0.021), a thinner inlay (p = 0.041), and a lower position of the patella (p = 0.041) were associated with AKP. Although no correlation with AKP was found (p = 0.346, resp. p = 0.154), we observed significantly decreased Young's modulus of the patellar and quadriceps tendons for the involved knee compared to the uninvolved knee (p < 0.001).

CONCLUSION

In conclusion, quadriceps muscle strength, inlay thickness, and the patella position might be of particular relevance in avoiding postsurgical AKP. Future studies with larger sample sizes are needed to clarify the impact of quadriceps muscle strength and the postoperative patella position as well as the role of SWE as a personalized modifiable prediction marker.

The ulnar collateral ligament responds to stress in professional pitchers

BACKGROUND

Our purpose with this study was to determine the response of the ulnar collateral ligament (UCL) in professional pitchers after exposure to a season of pitching and to rest during an off-season.

METHODS

In a prospective study supported by Major League Baseball, all pitchers within a single professional baseball club were enrolled. An ultrasound of the ligament was then performed by a single fellowship-trained ultrasonographer at the beginning of the season (T1), the end of the season (T2), and the beginning of the following season (T3). We measured the UCL thickness and ulnotrochlear joint opening at 30° of flexion with and without stress. Two ultrasound images were saved. Inter- and intra-rater reliability were determined. A multivariable analysis was conducted.

RESULTS

A total of185 total pitchers were included: 94 pitchers at T1, 83 at T2, and 118 at T3. These pitchers had 12 [7, 15] (median [interquartile range]) years of pitching experience and had a peak velocity of 95 [93, 97] miles/hour. Intra- and inter-rater reliability were excellent. The baseline UCL thickness was associated with peak velocity (P = .031) and prior UCL reconstruction (P = .024). After accounting for pitching experience, peak velocity, and prior UCL reconstruction, thickness increased during the season (P = .002) and decreased during the off-season (P = .001). After accounting for these same variables, valgus laxity at 30° increased during the season (P = .002) and decreased during the off-season (P = .029).

CONCLUSION

The UCL responds to stress in professional pitchers by becoming thicker and more lax, and responds to rest by becoming thinner and less lax.

The Influence of a 14-Week Infantry Commanders Courses on the Achilles Tendon and Patellar Tendon Structure

INTRODUCTION

Alternated tendon structure may raise stress to the musculoskeletal structures and may increase the potential for overuse injury. Screening the tendon structure of soldiers pre- and post-participation in a strenuous combat course is essential. The aim of the present study was to investigate the influence of a 14-week infantry commanders courses on the Achilles tendon (AT) structure and patellar tendon (PT) structure in combat soldiers.

MATERIALS AND METHODS

Ninety-eight participants from an infantry commanders course were screened pre- and post-course for the AT and PT structures, using ultrasonographic tissue characterizaton (UTC) imaging to capture a 3D structure of four echo-type fibers (I-IV).

RESULTS

In both tendons, the mean relative frequency of echo-type I fibers significantly decreased from pre- to post-testing, with a significant increase in the relative frequency of echo-types II, III, and IV fibers. In the AT, 60.2% of the subjects showed positive differences (between pre- and post-testing in the echo-type III + IV fiber ("worsened" tendon structure), whereas in the PT, 92.2% of the subject showed an increased frequency. No significant correlation (r = 0.108; P = .324) was found between the differences of echo-type III + IV fibers of the AT and that of the PT.

CONCLUSIONS

Loads to the musculoskeletal structures along the combat course increased the mean relative frequency of the "reduced" echo-type fibers (III + IV) in both the AT structure and the PT structure. Yet, whereas in the AT around 40% of the soldiers showed an improved tendon structure along the course, in the PT less than 10% of the soldiers showed that improvement. Soldiers and commanders should be aware of the different influence of the loading exercises along the course on the AT and on the PT structure, as "reduced" tendons structure might put the soldiers at higher risk for injury in the future.

Quadriceps and Patellar Tendon Thickness and Stiffness in Elite Track Cyclists: An Ultrasonographic and Myotonometric Evaluation

Track cyclists are required to perform short- and long-term efforts during sprint and endurance race events, respectively. The 200 m flying sprint races require maximal power output and anaerobic capacity, while the 4,000 m pursuit cyclists demand a high level of aerobic capacity. Our goal was to investigate spatial changes in morphological and mechanical properties displayed using 3D topographical maps of the quadriceps muscle and tendons after 200 m flying start and 4,000 m individual pursuit race in elite track cyclists. We hypothesized a non-uniform distribution of the changes in the quadriceps muscle stiffness (QM_stiff), and acute alterations in quadriceps tendon (QT_thick) and patellar tendon (PT_thick) thickness. Fifteen men elite sprint and 15 elite men endurance track cyclists participated. Sprint track cyclists participated in a 200 m flying start, while endurance track cyclists in 4,000 m individual pursuit. Outcomes including QT_thick (5–10–15 mm proximal to the upper edge of the patella), PT_thick (5–10–15–20 mm inferior to the apex of the patella)—using ultrasonography evaluation, QM_stiff, and quadriceps tendon stiffness (QT_stiff) were measured according to anatomically defined locations (point 1–8) and patellar tendon stiffness (PT_stiff)—using myotonometry, measured in a midway point between the patella distal and the tuberosity of tibial. All parameters were assessed before and after (up to 5 min) the 200 m or 4,000 m events. Sprint track cyclists had significantly larger QT_thick and PT_thick than endurance track cyclists. Post-hoc analysis showed significant spatial differences in QM_stiff between rectus femoris, vastus lateralis, and vastus medialis in sprint track cyclists. At before race, sprint track cyclists presented significantly higher mean QT_thick and PT_thick, and higher QM_stiff and the QT_stiff, as compared with the endurance track cyclists. The observed changes in PT_Thick and QT_Thick were mostly related to adaptation-based vascularity and hypertrophy processes. The current study suggests that assessments using both ultrasonography and myotonometry provides crucial information about tendons and muscles properties and their acute adaptation to exercise. Higher stiffness in sprint compared with endurance track cyclists at baseline seems to highlight alterations in mechanical properties of the tendon and muscle that could lead to overuse injuries.

Evaluation of patellar tendinopathy using the single leg decline squat test: Is pain location important?

STUDY DESIGN

A cross-sectional study of non-elite volleyball players aged 13-17years.

OBJECTIVES

To evaluate the presence and location of pain during the single leg decline squat (SLDS) and compare patellar tendon thickness, structure, neovascularisation and symptom severity between SLDS-derived groups.

METHODS

32 male and 25 female participants attending a 5-day volleyball training camp underwent clinical evaluation by SLDS, describing the location of pain during this test using a pain map. The patellar tendon was examined using ultrasound imaging, performed by an assessor blinded to other assessments. Differences between participants experiencing local patellar tendon pain (PTP), other knee pain (OKP) or no-pain during the SLDS were evaluated.

RESULTS

Fifteen (26.3%) participants experienced pain during the SLDS. Local PTP was recorded for 12.3% and OKP for 10.5% of right legs. The PTP group was distinguished from the other groups by larger thickness and cross-sectional area of the mid-patellar tendon (p < 0.001), more frequent neovascularisation (p = 0.005) and greater pain and disability (p < 0.036). No differences between OKP and no-pain groups was observed.

CONCLUSION

Adolescent non-elite volleyball players reported symptoms indicative of patellar tendinopathy. In this cohort, the SLDS test combined with a pain map was associated with imaging and questionnaire-based outcomes.

LEVEL OF EVIDENCE

Diagnosis, Level 2; Cross-sectional study.

Can Achilles and patellar tendon structures predict musculoskeletal injuries in combat soldiers?

Aiming to investigate whether Achilles tendon (AT) structure and patellar tendon (PT) structure are risk factors for musculoskeletal injuries in combat soldiers, 168 participants were recruited from an infantry commander's course. The AT and PT were examined pre-course using UTC to capture the structure of four echo-type fibers (I-IV). All injuries were assessed by military physicians pre-course and throughout the 14-week course. Soldiers who were injured during the course had a significantly higher pre-course prevalence of AT and PT echo-type III and echo-type IV compared to soldiers that were not injured during the course. Variables that were found to be associated with injured/non-injured participants were echo-type III + IV of the PT (OR = 1.44, 95% CI = 1.24-1.68) and echo-type III of the AT (OR = 1.69, 95% CI = 1.35-2.12). ROC analyses showed that the best model, exhibiting both high sensitivity and low specificity, was that participants with PT echo-type III + IV > 10% or AT echo-type III >8.5% had the highest risk of being injured during the course. In conclusions, the tendon structure at the beginning of high-intensity activity or physical training program might be a risk factor for subsequent injury during the course. Soldiers and high-level athletes should be aware of the cutoff points for fiber types in tendon structure that might put them at high risk for future injury. At-risk soldiers/athletes should be provided with an intervention program before they start their training program, with the aim of improving the tendon structure and preventing subsequent injury.

Individualized Muscle-Tendon Assessment and Training

The interaction of muscle and tendon is of major importance for movement performance and a balanced development of muscle strength and tendon stiffness could protect athletes from overuse injury. However, muscle and tendon do not necessarily adapt in a uniform manner during a training process. The development of a diagnostic routine to assess both the strength capacity of muscle and the mechanical properties of tendons would enable the detection of muscle-tendon imbalances, indicate if the training should target muscle strength or tendon stiffness development and allow for the precise prescription of training loads to optimize tendon adaptation. This perspective article discusses a framework of individualized muscle-tendon assessment and training and outlines a methodological approach for the patellar tendon.

Evaluation of Postoperative Changes in Patellar and Quadriceps Tendons after Total Knee Arthroplasty-A Comprehensive Analysis by Shear Wave Elastography, Power Doppler and B-mode Ultrasound

RATIONALE AND OBJECTIVES

Up to now, the diagnosis of tendinopathies is based on conventional B-mode-ultrasound (B-US), Power Doppler-ultrasound (PD-US), and magnetic resonance imaging. In the past decade, Shear Wave Elastography (SWE) has been introduced in tendon imaging, for example in athletes or patients suffering from tendinopathy. SWE allows real-time quantification of tissue stiffness, and, by this, the assessment of the mechanical properties of a tendon and its changes during acute disease and tendon healing. So far there are no ultrasound-based studies that have evaluated postoperative tendon changes, anatomical and mechanical properties and tendon healing of the patellar, and quadriceps tendon following Total Knee Arthroplasty (TKA). The purpose of this prospective study was two-fold: first to analyze morphologic, vascular, and mechanical properties of patellar and quadriceps tendons in patients following TKA; and, second to evaluate possible changes thereof and their visibility in the course of time.

MATERIALS AND METHODS

Observational cross-sectional, IRB-approved study in 63 postoperative patients with a total of 76 total knee arthroplasties (50 unilateral, 13 bilateral) and 50 nonoperated knees for comparison, resulting in 152 postoperative patellar- and quadriceps and 100 nonoperated patellar- and quadriceps-tendons for comparative analysis. For further examination, we divided the 63 patients into two groups according to the duration since surgery (group A < 24 months; group B > 24 months). All patients completed a standardized questionnaire, furthermore the Knee Society score and the Knee Society function score. The amount of experienced pain was assessed using the ordinal numeric rating scale and the presence of anterior knee pain was examined. Subsequently every participant underwent a standardized multimodal ultrasound protocol consisting of B-US, PD-US, and SWE of the left and right patellar and quadriceps tendons.

RESULTS

Using the different US-modalities, operated patellar, and quadriceps tendons (n = 152) were significantly more frequent classified as pathological (B-US) (p < 0.001), the mean Ohberg score was significantly higher (PD-US) (p < 0.001), and the tendons were significantly softer (SWE) than their nonoperated counterparts (n = 100). Mean SWE-value of postoperative patellar tendons was 45.66 ± 14.84 kPa versus 60.08 ± 19.13 kPa in nonoperated knees (p < 0.001). Mean SWE-value of postoperative quadriceps tendons was 35.73 ± 15.66 kPa versus 52.69 ± 16.20 kPa in nonoperated knees (p < 0.001). Comparing the two postoperative groups (group A and B), we recognized a significant decrease of pathologically classified patellar and quadriceps tendons (B-US and PD-US) in group B. The early postoperatively reduced SWE values slightly increased during the course of time.

CONCLUSION

After TKA, patellar, and quadriceps tendons show significant measurable alterations in B-US, PD-US, and SWE. Especially a significant decrease of tendon stiffness in operated knees, as assessed by SWE, might be a surrogate marker for changed mechanical properties. These alterations improve, the longer ago the surgery was. The quantitative information obtained by SWE could be of particular interest in follow-up and therapy monitoring after TKA. Knowledge about tendon stiffness and it's varieties in different population groups (e.g. athletes, elderly, postoperative patients) is crucial to sonographically rate a tendon as "healthy" or "diseased."

Bilateral changes in tendon structure of patients diagnosed with unilateral insertional or midportion achilles tendinopathy or patellar tendinopathy

PURPOSE

Changes in tendon structure are commonly seen in patients with unilateral achilles (AT) or patellar (PT) tendinopathy but might also be present on the asymptomatic side, indicating a higher risk for developing symptoms. The aim of this study is to compare tendon structure of the symptomatic side with the asymptomatic side in AT and PT patients and control subjects.

METHODS

A total of 46 patients with unilateral AT (16 insertional and 30 midportion) and 38 with unilateral PT were included. For the control group, a total of 18 Achilles tendons and 25 patellar tendons were scanned. Tendon structure was assessed using ultrasound tissue characterisation (UTC), which quantifies tendon organisation dividing the structure into four different echo types (I-IV).

RESULTS

There were significant differences in echo types I, III, and IV between symptomatic and asymptomatic sides and controls. Additionally, there was a significant difference between the symptomatic and the asymptomatic side for all tendinopathy locations. In the insertional AT tendon portion, the symptomatic side showed a higher percentage of echo type III. For the midportion AT, the symptomatic side showed a lower percentage of echo type I and a higher percentage of echo types III and IV. For the patellar tendon, the symptomatic side showed a higher percentage of echo types III and IV. All differences were higher than the minimal detectable changes.

CONCLUSION

Although patients have symptoms unilaterally, the tendon structures are compromised on both sides. These results stress the importance of monitoring both symptomatic and asymptomatic tendon structures and in addition highlight that the asymptomatic side should not be used as reference in clinical practice.

LEVEL OF EVIDENCE

III.

Low prevalence of patellar tendon abnormality and low incidence of patellar tendinopathy in female collegiate volleyball players

The prevalence of patellar tendinopathy has been reported to be as high as 50% in elite male volleyball (VB) players; however, the rate of injury in female collegiate VB athletes is unknown. The purpose of this study was to 1) identify the prevalence of ultrasonographic evidence of patellar tendon abnormality at the start of the preseason in female collegiate VB players; 2) report the incidence of tendinopathy during the season; and 3) determine if the preseason presence of tendon abnormality is associated with onset of disease. One hundred and six female collegiate VB players had both patellar tendons imaged. Incidence of patellar tendinopathy was tracked during the course of the 4-month season. Twenty-two athletes presented with ultrasonographic evidence of patellar tendon abnormality in at least one knee at the start of the preseason. The incidence of time-loss patellar tendinopathy was 0.26 (95% CI: 0.04, 0.85) per 1000 athletic exposures. This study was unable to determine if preseason presence of tendon abnormality was associated with a greater risk of tendinopathy due to power. The prevalence of tendon abnormality in the preseason and the incidence of patellar tendinopathy in female collegiate VB players are lower than that observed in other populations.

Shear Wave Elastography (SWE) of Asymptomatic Achilles Tendons: A Comparison Between Semiprofessional Athletes and the Nonathletic General Population

RATIONALE AND OBJECTIVES

It has been shown that Shear Wave Elastography (SWE) is a useful tool to evaluate tendon stiffness, e.g. in diagnosing tendinopathies, as diseased or injured tendons are intra-individually softer than healthy ones. But reference values between different population groups are still missing. The purpose of this prospective clinical study was two-fold: First, to comparatively analyse Achilles tendon stiffness between asymptomatic semiprofessional athletes and an asymptomatic nonathletic control group. Second, to evaluate specificity, with which SWE is able to predict absence of clinical symptoms in asymptomatic individuals, compared to B-mode-Ultrasound (B-US) and Power Doppler-Ultrasound (PD-US).

MATERIALS AND METHODS

Prospective clinical study in 68 asymptomatic healthy participants, 33 (48.5%) of them semiprofessional athletes with at least five training units of running per week and 35 (51.5 %) normal nonathletic persons, asymptomatic respectively. A consecutive of 136 Achilles tendons underwent standardized multi-modal ultrasound, consisting of B-US, PD-US, and SWE (Aixplorer, Supersonic). Pathologic structural changes at B-US, increased Doppler signal PD-US and quantitative ROI-based-analysis of tendon elasticity in kilopascal (kPa) were performed in all participants. Tendon stiffness was compared intra-individually between right and left side in each participant. SWE values between athletes and nonathletes were compared by using student's t test (p < 0.05). To evaluate the ability of different sonographic modalities in predicting "absence of clinical symptoms", specificities of B-US, PD-US, and SWE were calculated and compared among each other.

RESULTS

Mean SWE-value for Achilles tendon was 183.8 kPa (± 98 kPa) in athletes and 103.6 kPa (± 30.5 kPa) in the nonathletic control group. The difference between athletes and non-athletes was statistically significant (p < 0.001). No significant differences were found intra-individually between right and left side: athlete mean: right: 187.2 kPa (SD ± 45.2 kPa)/left: 180.4 kPa (SD 39.7 kPa); nonathlete mean: right: 105.4 kPa (SD 34.9 kPa)/left: 101.8 kPa (SD 28.9 kPa). Specificity with which asymptomatic tendons were rated as "inconspicuous" was 60.6% for B-US, 93.9% for PD-US and 96.3% for SWE.

CONCLUSION

Healthy athletes exhibit significantly higher SWE-values in Achilles tendons than healthy nonathletic participants, which means that they have significantly stiffer tendons, possibly caused by repeated training. SWE is able to measure and display these effects. These interindividual differences should be taken into consideration, especially when rating a tendon as "healthy" or "diseased", because a "softer" tendon does not necessarily mean to be affected.

Distinguishing Quadriceps Tendinopathy and Patellar Tendinopathy: Semantics or Significant?

Jumper's knee is not synonymous with patellar tendinopathy. The term includes patellar tendinopathy and quadriceps tendinopathy. Although the patellar and quadriceps tendons work in tandem as part of the extensor mechanism of the knee, they have distinct anatomy and functional roles. As a result, there are probable differences in risk factors, etiology, and response to treatment. It is time to clinically separate patellar tendinopathy and quadriceps tendinopathy and design more specific rehabilitation programs. In this Viewpoint, the authors will (1) provide a rationale for distinguishing the 2 clinical entities-patellar tendinopathy and quadriceps tendinopathy-for treatment decision making, and (2) identify areas of research priority in quadriceps tendinopathy. J Orthop Sports Phys Ther 2019;49(9):627-630. doi:10.2519/jospt.2019.0611.

How strong is the evidence that conservative treatment reduces pain and improves function in individuals with patellar tendinopathy? A systematic review of randomised controlled trials including GRADE recommendations

OBJECTIVE

To determine the effectiveness of conservative treatment (CT) on pain and function in patients with patellar tendinopathy (PT) compared with minimal intervention (MI) or other invasive intervention, or in addition to decline eccentric squat.

METHODS

Searches were performed in MEDLINE, Embase, Cochrane, PEDro, SPORTDiscus, CINAHL and AMED databases. All randomised trials that evaluated CT (any intervention not involving invasive procedures or medication) in individuals with PT were included. Two reviewers screened studies, extracted data and assessed risk of bias of all included studies. Where suitable, meta-analyses were conducted; we assessed certainty of the evidence using GRADE methodology.

RESULTS

When compared with MI, CT did not improve pain (weighted mean difference (WMD) -2.6, 95% CI -6.5 to 1.2) or function (WMD 1.8, 95% CI -2.4 to 6.1) in the short-term (up to 3 months) follow-up. When compared with invasive intervention, CT did not improve pain (WMD 0.7, 95% CI -0.1 to 1.4) or function (WMD -6.6, 95% CI -13.3 to 0.2) in the short-term follow-up. No overall effects were found for combined CT (when a conservative intervention was added to decline eccentric squat) on pain (WMD -0.5, 95% CI -1.4 to 0.4) or function (WMD -2.3, 95 % -9.1 to 4.6) at short-term follow-up. Single studies showed an effect on pain with iontophoresis at short-term follow-up (d = 2.42) or dry needling at medium/long-term follow-up (d = 1.17) and function with exercise intervention at medium/long-term follow-up (over 3 months) (d = 0.83).

SUMMARY/CONCLUSION

Our estimates of treatment effect have only low to very low certainty evidence to support them. This field of sports medicine/sports physiotherapy urgently needs larger, high-quality studies with pain and function among the potential primary outcomes.

Sonographic Measurement of the Patellar Tendon Should Predict Autograft Bone Patellar Tendon Bone (BPTB) Size: Comparison of Anatomical and Clinical Findings

The use of BPTB autograft is frequently used in ACL reconstruction, however, the risk of potential failure in patients with an anatomically unfavorable patellar tendon may predispose to reconstruction failure. Anatomical study of the extensor apparatus of the knee can provide knowledge about the best option obtain the graft and perform a better preoperative planning. Musculoskeletal ultrasound is a simple, reproducible, affordable technique that could be valid for patellar tendon evaluation. The objective of this study is to evaluate the reproducibility of the patellar tendon measurements by ultrasound and compare them with anatomical measurements, both in cadaver and patients undergoing ACLR. The study consists of two phases; first anatomical study in cadaver. The ultrasound measurement was performed by determining the length, width and thickness of the patellar tendon, both by ultrasound and anatomical dissection. The second phase is a cohort of 42 patients pending surgical ACLR. Previous ultrasound and intraoperative measurements were obtained. Regarding the anatomical study, statistical analysis did not show any differences comparing the measurements in length (p = ns) and thickness (p = ns) of the patellar tendon, although differences were obtained when comparing the results obtained for the width of the tendon after the ultrasound and anatomical measurement (p < 0.001). Same results were obtained in second phase of the study. The reproducibility of ultrasound measurements of the PT is comparable to intraoperatively measurements (without width measurement). These findings can be useful for preoperative planning in the reconstruction of ACL with BPTB Graft and to assess technical modifications prior to surgery.

Quadriceps tendinopathy: a review-part 1: epidemiology and diagnosis

Overuse injuries of the extensor mechanism of the knee are common in both athletes and non-athletes and usually occur during activities associated with repetitive loading, stress, and knee extension. Historically, they have been labeled as Jumper's knee due to the high prevalence seen in the athletic community. In many published reports, the name "patellar tendinopathy" is used to describe this disorder of the quadriceps tendon at the patellar insertion, and the names are often used interchangeably. Numerous reports have been published describing extensor mechanism injuries in athletes, but there is a paucity of studies that focus on quadriceps tendinopathy. In addition, there is no universally accepted classification system for tendon pathology. Therefore, we performed a comprehensive literature review of these studies. This review consists of 2 parts. In the first part we review: (I) epidemiology and (II) diagnosis of quadriceps tendinopathy in the athlete as well as the general population. In the second part we discuss: (I) classification; (II) prognosis; and (III) treatment results.

Jumper's knee mechanical consequences in professional basketball players: the "Camel's Back curve"

PURPOSE

Jumper's knee is characterized by an anterior knee pain during tendon palpation and can be classified in overuse pathologies, secondary to repetitive jumps. The prevalence is high in professional basketball players. It is responsible for an alteration of the motor control inducing a strength deficit of the quadriceps. We aimed to describe an isokinetic curve anomaly, a double-humped curve called "Camel's Back curve", consequence of a jumper's knee history.

METHODS

170 Professional basketball players were enrolled (24.8 ± 4.6 years; 91.8 ± 12.0 kg, 194 ± 9.0 cm). All players performed isokinetic tests of the knee extensors on a concentric mode at the angular speed of 60°/s and 180°/s.

RESULTS

43 players had a jumper's knee history and 35 (81%) had a "Camel's Back curve" at 60°/s. The sensitivity and the specificity of this curve were 81.3% and 100%, respectively. The minimum torque of strength was decreased from 12 to 18% compared to the 2 maximal peaks. Yet, the strength measured every 5° of ROM was significantly different between the players with "Camel's Back curve" and those with normal curve.

CONCLUSIONS

"Camel's Back curve" had never been described in that context. It may be secondary to a protective inhibitory mechanism which could alter jumping. The presence of a "Camel's Back curve" would enable clinicians to adapt physical preparation, knee rehabilitation, and trainings to improve players performances.