Anthropometry, physical performance, and ultrasound patellar tendon abnormality in elite junior basketball players: a cross-sectional study

Objective: Patellar tendinopathy has been reported to be associated with many intrinsic risk factors. Few have been fully investigated. This cross-sectional study examined the anthropometric and physical performance results of elite junior basketball players with normal or abnormal patellar tendons to see if any measures were associated with changes in tendon morphology.

Methods: Agility, leg strength, endurance, and flexibility were measured in 71 male and 64 female players. A blinded radiologist ultrasonographically examined their patellar tendons and athletes were grouped as having normal or abnormal tendons. One-way ANOVA was used to test for differences in anthropometric and physical performance data for athletes whose tendons were normal or abnormal (unilateral or bilateral tendinopathy) on ultrasound.

Results: Results show that females with abnormalities in their tendons had a significantly better vertical jump (50.9±6.8 cm) than those with normal tendons (46.1±5.4 cm) (p = 0.02). This was not found in males. In males, the mean sit and reach in those with normal tendons (13.2±6.7 cm) was greater (p<0.03) than in unilateral tendinopathy (10.3±6.2 cm) or in bilateral tendinopathy (7.8±8.3 cm). In females, those with normal tendons (13.3±4.8 cm) and bilateral tendinopathy (15.8±6.2 cm) were distinctly different from those with unilateral tendinopathy (7.9±6.6 cm).

Conclusion: Flexibility and vertical jump ability are associated with patellar tendinopathy and the findings warrant consideration when managing young, jumping athletes.

High reproducibility of patellar tendon vascularity assessed by colour doppler ultrasonography : a reliable measurement tool for quantifying tendon pathology

Background: This study examined whether patellar tendon vascularity could be quantified accurately in the clinical setting using colour Doppler ultrasonography.

Methods: A sonographer and two radiologists visually estimated tendon vascularity in millimetres in 74 tendons during ultrasound (US) examination and from hard copy films. These estimates were then compared to the length of vessels measured from the digital image in millimetres and the correlation between them was determined. A subset of 16 tendons was used to compare the estimates of vascularity by two examiners at US examination.

Results: The estimation of vascular length at US examination correlated highly with the measured vascular length (r = 0.92; 95% confidence interval (CI) 0.87 to 0.94), as did the length estimated from the films (r = 0.94; 95% CI 0.9 to 0.96). The correlation between examiners was 0.84 (95% CI 0.51 to 0.94) for the estimates made during US examination and 0.85 (95% CI 0.59 to 0.95) for the vessel lengths measured from the digital images.

Conclusions: These excellent correlations indicate that tendon vascularity can be reliably estimated using colour Doppler ultrasonography and tendon vascularity could therefore be used by clinicians to rate clinical change. This method of quantifying tendon vascularity could also be used in research to investigate the effects of tendon treatments on vascularity.

Vascularity and pain in the patellar tendon of adult jumping athletes : a 5 month longitudinal study

Background: This study investigated changes in tendon vascularity in 102 (67 men and 35 women) volleyball players over a 6 month competitive season.

Methods: Athletes were examined with both grey scale ultrasound and standardised colour Doppler settings. Vessel length and pain were measured each month on five separate occasions. Vascular tendons were divided into (i) those that were vascular on all occasions (persistent vascularity) and (ii) those that were vascular on more than two but less than five occasions (intermittent vascularity).

Results: A total of 41 of the 133 abnormal tendons were vascular on two or more occasions. Of these, 16 had persistent vascularity and 25 had intermittent vascularity. There was no significant difference in the prevalence of vascularity between men and women. None of the tendons had a pattern of vascularity over the season that could be clearly interpreted as the onset or resolution of vascularity. Subjects with changes in both tendons were more likely to have persistent vascularity (p = 0.045). Vessels were longer in tendons with persistent vascularity (p<0.000) and pain was significantly greater (p = 0.043) than in tendons with intermittent vascularity. Tendons with intermittent vascularity had similar pain scores on all days, whether or not they had detectable blood flow.

Asymptomatic hypoechoic regions on patellar tendon ultrasound : a 4-year clinical and ultrasound followup of 46 tendons

Patellar tendon ultrasound appearance is commonly used in clinical practice to diagnose patellar tendinopathy and guide management. Using a longitudinal study design we examined whether or not the presence of a hypoechoic ultrasonographic lesion in an asymptomatic patellar tendon conferred a risk for developing jumper's knee compared with a tendon that was ultrasonographically normal. Ultrasonographic, symptomatic and anthropometric assessment was completed at baseline and followup. Magnetic resonance imaging was performed on four tendons that resolved ultrasonographically in the study period. Forty-six patellar tendons were followed over 47±11.8 months. Eighteen tendons were hypoechoic at baseline and 28 were ultrasonographically normal. Five tendons resolved ultrasonographically in the study period. Magnetic resonance imaging in four of these tendons was normal. Seven normal patellar tendons at baseline developed a hypoechoic area but only two became symptomatic. Analysis of ultrasonography at baseline and clinical outcome with Fisher's exact test shows there is no association between baseline ultrasound changes and symptoms at followup. In this study there is no statistically significant relationship between ultrasonographic patellar tendon abnormalities and clinical outcome in elite male athletes. Management of jumper's knee should not be solely based on ultrasonographic appearance; clinical assessment remains the cornerstone of appropriate management.

Increased versican content is associated with tendinosis pathology in the patellar tendon of athletes with jumper

Expansion of the extracellular matrix is a prominent but poorly characterized feature of tendinosis. The present study aimed to characterize the extent and distribution of the large aggregating proteoglycan versican in patients with patellar tendinosis. We obtained tendon from tendinopathy patients undergoing debridement of the patellar tendon and from controls undergoing intramedullary tibial nailing. Versican content was investigated by Western blotting and immunohistochemistry. Microvessel thickness and density were determined using computer-assisted image analysis. Markers for smooth muscle actin, endothelial cells (CD31) and proliferating cells (Ki67) were examined immunohistochemically. Western blot analysis and immunohistochemical staining revealed elevated versican content in the proximal patellar tendon of tendinosis patients (P=0.042). Versican content was enriched in regions of fibrocartilage metaplasia and fibroblast proliferation, as well as in the perivascular matrix of proliferating microvessels and within the media and intima of arterioles. Microvessel density was higher in tendinosis tissue compared with control tissue. Versican deposition is a prominent feature of patellar tendinosis. Because this molecule is not only a component of normal fibrocartilagenous matrices but also implicated in a variety of soft tissue pathologies, future studies should further detail both pathological and adaptive roles of versican in tendons.

Prospective study of change in patellar tendon abnormality on imaging and pain over volleyball season

Objective: Patellar tendon injury, defined by tendon abnormality (TA) on imaging and by pain, is common among volleyball players, but little is known about change in this injury over a volleyball season. Increased activity in the season compared with the off season may result in the development of TA and/or pain. This study investigated the behaviour of TA and pain over a competitive volleyball season.

Methods: Tendon abnormality and pain were measured in 101 volleyball players at the beginning and end of a season. Pain was measured with the single leg decline squat test, which loads the patellar tendon, and TA was detected with ultrasound imaging. Hours of weekly activity were measured and compared during the season and the off season. The proportion of tendons that underwent development and resolution in TA and/or pain over the season was investigated.

Results: Hours of weekly activity was greater during the season than in the off season. Most of the tendons investigated (66.3%) did not undergo a change in TA or pain over the season. Tendon abnormality and/or pain developed in 16.6% of tendons and resolved in 11.2%.

Conclusions: The tendons of volleyball players respond variably to the increased load over the season. Change in TA and pain does not appear to be entirely dependent upon load.

Reduced ankle dorsiflexion range may increase the risk of patellar tendon injury among volleyball players

Patellar tendon injury, a chronic overuse injury characterised by pain during tendon loading, is common in volleyball players and may profoundly restrict their ability to compete. This cross-sectional study investigated the association between performance factors and the presence of patellar tendon injury. These performance factors (sit and reach flexibility, ankle dorsiflexion range, jump height, ankle plantarflexor strength, years of volleyball competition and activity level) were measured in 113 male and female volleyball players. Patellar tendon health was determined by measures of pain and ultrasound imaging. The association between these performance factors and patellar tendon health (normal tendon, abnormal imaging without pain, abnormal imaging with pain) was investigated using analysis of variance. Only reduced ankle dorsiflexion range was associated with patellar tendinopathy (p < 0.05). As coupling between ankle dorsiflexion and eccentric contraction of the calf muscle is important in absorbing lower limb force when landing from a jump, reduced ankle dorsiflexion range may increase the risk of patellar tendinopathy.

The ultrasound appearance of the patellar tendon attachment to the tibia in young athletes is conditional on gender and pubertal stage

This cross-sectional study investigated the imaging appearance of the previous termpatellarnext term tendon attachment to the tibia in young male and female tennis players of different ages and pubertal status. Forty-four competitive young players, who had been playing tennis at least for 2 years, were recruited from a tennis school and local tennis clubs. All subjects had bilateral ultrasound imaging of the previous termpatellarnext term tendon attachment to the tibia. Standard anthropometric measurements, pubertal status and injury history were recorded. Ultrasound appearance of the previous termpatellarnext term tendon attachment was categorised into three stages: cartilage attachment, insertional cartilage and mature attachment. Cartilage attachment was more prevalent in boys (32%) and extended further into puberty (until Tanner stage 4) compared to girls (6% and Tanner stage 1). Tendons with Osgood–Schlatter Disease symptoms (n = 3) did not have a cartilage attachment. Imaging appearance commonly seen in young active athletes, consistent with a clinical diagnosis of OSD, was more common in boys and in the pre- and peri-pubertal stages.

Anthropometric risk factors for patellar tendon injury among volleyball players

Objective: Abnormal imaging in the patellar tendon reveals pathology that is often associated with knee pain. Anthropometric measures of body size and mass, such as height, weight and waist-to-hip ratio (WHR), have been individually associated with abnormal imaging. The aim of this study was to investigate the anthropometric factors that have the strongest relationship with abnormal imaging in volleyball players.

Methods: Height, weight, body mass index (BMI), waist girth, hip girth and WHR were measured in a cohort of 113 competitive volleyball players (73 men, 40 women). The univariate (ANOVA) and multivariable (discriminant function analysis) association between abnormal imaging and these anthropometric factors were investigated.

Results: No significant association was found in the female volleyball players. A significant univariate association was observed between abnormal imaging and heavier weight, greater BMI, larger waist and hip girth and larger WHR in the male volleyball players. Waist girth was the only factor that retained this association in a multivariable model (p<0.05).

Conclusions: Men with a waist girth greater than 83 cm seem to be at greater risk of developing patellar tendon pathology. There may be both mechanical and biochemical reasons for this increased risk.

Reproducibility and clinical utility of tendon palpation to detect patellar tendinopathy in young basketball players

Background—Palpation is an important clinical test for jumper's knee.

Objectives—To (a) test the reproducibility of palpation tenderness, (b) evaluate the sensitivity and specificity of palpation in subjects with clinical symptoms of jumper's knee, and (c) determine whether tenderness to palpation may serve as a useful screening test for patellar tendinopathy. The yardstick for diagnosis of patellar tendinopathy was ultrasonographic abnormality.

Methods—In 326 junior symptomatic and asymptomatic athletes' tendons, palpation was performed by a single examiner before ultrasonographic examination by a certified ultrasound radiologist. In 58 tendons, palpation was performed twice to test reliability. Tenderness to palpation was scored on a scale from 0 to 3 where 0 represented no pain, and 1, 2, and 3 represented mild, moderate, and severe tenderness respectively.

Results—Patellar tendon palpation was a reliable examination for a single examiner (Pearson r = 0.82). In symptomatic tendons, the positive predictive value of palpation was 68%. As a screening examination in asymptomatic subjects, the positive predictive value of tendon palpation was 36–38%. Moderate and severe palpation tenderness were better predictors of ultrasonographic tendon pathology than absent or mild tenderness (p<0.001). Tender and symptomatic tendons were more likely to have ultrasound abnormality than tenderness alone (p<0.01).

Conclusions—In this age group, palpation is a reliable test but it is not cost effective in detecting patellar tendinopathy in a preparticipation examination. In symptomatic tendons, palpation is a moderately sensitive but not specific test. Mild tenderness in the patellar tendons in asymptomatic jumping athletes should be considered normal.

Patellar tendons with normal imaging and pain: change in imaging and pain status over volleyball season

Objective: Patellar tendon injury commonly presents as abnormal imaging with pain or abnormal imaging without pain. Normal imaging with pain has also been reported clinically, but little is known about the behavior of these tendons over time. This study investigated the behavior of tendons with normal imaging and pain over a volleyball season.

Design: Prospective study.

Setting: Institutional.

Participants: One hundred and one male and female volleyball players.

Main outcome measurements: At the beginning and end of the season ultrasound determined imaging status and the single leg decline squat test determined pain. The imaging and pain status at follow-up of tendons with normal imaging and pain at baseline was reported and contrasted to the imaging and pain status of the other patellar tendon injuries.

Results: Tendons with normal imaging and pain [relative risk (RR) 15.1], abnormal imaging without pain (RR 14.6), and abnormal imaging with pain (RR 51.5) had a greater risk of having abnormal imaging with pain at the end of the season when compared with normal tendons (P < 0.01). Among tendons with normal imaging and pain at baseline, 27% had abnormal imaging without pain and 21% contained abnormal imaging with pain at the end of the season.

Conclusions: Patellar tendons with normal imaging and pain at the beginning of a volleyball season are equally as likely to have abnormal imaging and pain at the end of the season as tendons with abnormal imaging without pain. Normal imaging with pain may represent a clinically relevant patellar tendon injury.

Are unilateral and bilateral patellar tendinopathy distinguished by differences in anthropometry, body composition, or muscle strength in elite female basketball players?

Background: Overuse injury to the patellar tendon (patellar tendinopathy) is a major reason for interrupted training and competition for elite athletes. In both sexes, the prevalence of unilateral and bilateral tendinopathy has been shown to differ. It has been proposed that bilateral pathology may have a different aetiology from unilateral pathology. Investigation of risk factors that may be unique to unilateral and bilateral patellar tendinopathy in female athletes may reveal insights into the aetiology of this condition.
Objectives: To examine whether anthropometry, body composition, or muscle strength distinguished elite female basketball players with unilateral or bilateral patellar tendinopathy.
Methods: Body composition, anthropometry, and muscle strength were compared in elite female basketball players with unilateral (n = 8), bilateral (n = 7), or no (n = 24) patellar tendinopathy. Body composition was analysed using a dual energy x ray absorptiometer. Anthropometric measures were assessed using standard techniques. Knee extensor strength was measured at 180°/s using an isokinetic dynamometer. z scores were calculated for the unilateral and bilateral groups (using the no tendinopathy group as controls). z scores were tested against zero.
Results: The tibia length to stature ratio was approximately 1.3 (1.3) SDs above zero in both the affected and non-affected legs in the unilateral group (p<0.05). The waist to hip ratio was 0.66 (0.78) SD above zero in the unilateral group (p<0.05). In the unilateral group, leg lean to total lean ratio was 0.42 (0.55) SD above zero (p<0.07), the trunk lean to total lean ratio was 0.63 (0.68) SD below zero (p<0.05), and leg fat relative to total fat was 0.47 (0.65) SD below zero (p<0.09). In the unilateral group, the leg with pathology was 0.78 (1.03) SD weaker during eccentric contractions (p<0.07).
Conclusions: Unilateral patellar tendinopathy has identifiable risk factors whereas bilateral patellar tendinopathy may not. This suggests that the aetiology of these conditions may be different. However, interpretation must respect the limitation of small subject numbers.