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.

Achilles tendinopathy

Achilles tendon injury (tendinopathy) and pain occur in active individuals, when the tendon is subject to high or unusual load. Achilles tendinopathy can be resistant to treatment, and symptoms may persist despite both conservative and surgical intervention. The pathology of overuse tendinopathy is non-inflammatory, with a degenerative or failed healing tendon response. The diagnosis of Achilles tendinopathy requires excellent differential diagnosis and an understanding of the role of tendon imaging. Conservative treatment must include exercise, with a bias to eccentric contractions. Surgical treatment is effective after complete tendon rupture, but may not assist recovery from overuse tendinopathy. Further research into the clinical aspects of Achilles tendinopathy is required.

Patellar tendinopathy: pathomechanics and a modern approach to treatment

Patellar tendinopathy, a common condition in sport, can be recurrent and resistant to treatment, Risk factors include the level of training, biomechanics, and genetic factors. This review discusses several programs based on eccentric exercise and suggests principles for nonoperative treatment including improving shock absorption, load modification, and adaptation of the tendon to sporting stress. The level of pain that patients are asked to tolerate during tendon-exercise programs varies among programs, and it is unclear what level is optimal to stimulate tendon recovery. Rehabilitation presents several challenges: It can take a long time (3-12 months), exercise prescription in an athlete who is continuing to compete is not straightforward, and guidelines for treatment progression are poor, Nonoperative treatment can fail because of inappropriate exercise prescription and poor athlete compliance. If this occurs and surgical intervention is required, the athlete might still have an unpredictable outcome. Solutions to these problems require additional clinical research.

Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players

Background: Conservative treatment of patellar tendinopathy has been minimally investigated. Effective validated treatment protocols are required.

Objectives: To investigate the immediate (12 weeks) and long term (12 months) efficacy of two eccentric exercise programmes for the treatment of patellar tendinopathy.

Methods: This was a prospective randomised controlled trial of 17 elite volleyball players with clinically diagnosed and imaging confirmed patellar tendinopathy. Participants were randomly assigned to one of two treatment groups: a decline group and a step group. The decline group were required to perform single leg squats on a 25° decline board, exercising into tendon pain and progressing their exercises with load. The step group performed single leg squats on a 10 cm step, exercising without tendon pain and progressing their exercises with speed then load. All participants completed a 12 week intervention programme during their preseason. Outcome measures used were the Victorian Institute of Sport Assessment (VISA) score for knee function and 100 mm visual analogue scale (VAS) for tendon pain with activity. Measures were taken throughout the intervention period and at 12 months.

Results: Both groups had improved significantly from baseline at 12 weeks and 12 months. Analysis of the likelihood of a 20 point improvement in VISA score at 12 months revealed a greater likelihood of clinical improvements in the decline group than the step group. VAS scores at 12 months did not differ between the groups.

Conclusions: Both exercise protocols improved pain and sporting function in volleyball players over 12 months. This study indicates that the decline squat protocol offers greater clinical gains during a rehabilitation programme for patellar tendinopathy in athletes who continue to train and play with pain.

Tenocyte responses to mechanical loading in vivo : A role for local insulin-like growth factor 1 signaling in early tendinosis in rats

Objective
To investigate tenocyte regulatory events during the development of overuse supraspinatus tendinosis in rats.

Methods
Supraspinatus tendinosis was induced by running rats downhill at 1 km/hour for 1 hour a day. Tendons were harvested at 4, 8, 12, and 16 weeks and processed for brightfield, polarized light, or transmission electron microscopy. The development of tendinosis was assessed semiquantitatively using a modified Bonar histopathologic scale. Apoptosis and proliferation were examined using antibodies against fragmented DNA or proliferating cell nuclear antigen, respectively. Insulin-like growth factor 1 (IGF-1) expression was determined by computer-assisted quantification of immunohistochemical reaction. Local IGF-1 signaling was probed using antibodies to phosphorylated insulin receptor substrate 1 (IRS-1) and ERK-1/2.

Results
Tendinosis was present after 12 weeks of downhill running and was characterized by tenocyte rounding and proliferation as well as by glycosaminoglycan accumulation and collagen fragmentation. The proliferation index was elevated in CD90+ tenocytes in association with tendinosis and correlated with increased local IGF-1 expression by tenocytes and phosphorylation of IRS-1 and ERK-1/2. Both apoptosis and cellular inflammation were absent at all time points.

Conclusion
In this animal model, early tendinosis was associated with local stimulation of tenocytes rather than with extrinsic inflammation or apoptosis. Our data suggest a role for IGF-1 in the load-induced tenocyte responses during the pathogenesis of overuse tendon disorders.

A treatment algorithm for managing Achilles tendinopathy : new treatment options

Achilles tendinopathy affects athletes, recreational exercisers and even inactive people. The pathology is not inflammatory; it is a failed healing response. The source of pain in tendinopathy could be related to the neurovascular ingrowth seen in the tendon's response to injury. The treatment of Achilles tendinopathy is primarily conservative with an array of effective treatment options now available to the primary care practitioner. If conservative treatment is not successful, then surgery relieves pain in the majority of cases. Directing a patient through the algorithm presented here will maximise positive treatment outcomes.

Comparative accuracy of magnetic resonance imaging and ultrasonography in confirming clinically diagnosed patellar tendinopathy

Background: Diagnosis of patellar tendinopathy is based primarily on clinical examination; however, it is commonplace to image the patellar tendon for diagnosis confirmation, with the imaging modalities of choice being magnetic resonance imaging (MRI) and ultrasonography (US). The comparative accuracy of these modalities has not been established.

Hypothesis: Magnetic resonance imaging and US have good (>80%) accuracy and show substantial agreement in confirming clinically diagnosed patellar tendinopathy.

Study Design: Cohort study (diagnosis); Level of evidence, 2.

Methods: Magnetic resonance imaging and US (gray scale [GS-US] and color Doppler [CD-US]) features of 30 participants with clinically diagnosed patellar tendinopathy and 33 activity-matched, asymptomatic participants were prospectively compared. Accuracy, sensitivity, specificity, positive and negative predictive values, and the likelihood of positive and negative test results were determined for each technique.

Results: The accuracy of MRI, GS-US, and CD-US was 70%, 83%, and 83%, respectively (P = .04; MRI vs GS-US). The likelihood of positive MRI, GS-US, and CD-US was 3.1, 4.8, and 11.6, respectively. The MRI and GS-US had equivalent specificity (82% vs 82%; P = 1.00); however, the sensitivity of GS-US was greater than MRI (87% vs 57%; P = .01). Sensitivity (70% vs 87%; P = .06) and specificity (94% vs 82%; P = .10) did not differ between CD-US and GS-US.

Conclusions: Ultrasonography was more accurate than MRI in confirming clinically diagnosed patellar tendinopathy. GS-US and CD-US may represent the best combination for confirming clinically diagnosed patellar tendinopathy because GS-US had the greatest sensitivity, while a positive CD-US test result indicated a strong likelihood an individual was symptomatic.

Rehabilitation of Achilles and patellar tendinopathies

Achilles and patellar tendinopathies affect a broad range of the population and are difficult conditions to manage clinically. The pathology is persistent in the chronic tendon and can be considered to be failed healing. The exact cause of tendinopathy pain is unclear but may be related to changes in neurovascular structures.

Rehabilitation for Achilles and patellar tendinopathies is based on an exercise programme that aims to improve muscle–tendon function and normalise the pelvic/lower limb kinetic chain. This incorporates a programme for restoring and improving muscle strength, endurance and power and retraining sport-specific function.

Rehabilitation may take a prolonged period of time, both the athlete and clinician must be patient and persistent to maximise results from an exercise-based treatment.

Stress-shielding as a cause of insertional tendinopathy: the operative technique of limited adductor tenotomy supports this theory

The aetiology of tendinopathy is poorly understood. A new hypothesis proposed argues that tendinopathy may not be purely a tensile injury, rather that altered mechanics such as compression or stress-shielding may be important. Both tendon compression and a decrease in tendon load (stress-shielding) will induce change in a tendon similar to that seen in an insertional tendinopathy.

Stress-shielding as a cause of tendinopathy is supported by the clinical success of operative release of adductor longus. This surgery releases the superficial section of the normal adductor longus tendon at a point distal to the insertion. This may have the effect of transferring stress from the superficial section of the tendon to the stress-shielded deeper portion, and the induction of normal loads in both the deeper and superficial portions of the tendon may assist in tendon recovery. This interesting hypothesis and clinical intervention require further investigation

No effect of eccentric training on jumper's knee in volleyball plays. During the competitive season : a randomized clinical trial

Background: The effect of surgery on patellar tendinopathy (jumper's knee) is questionable, and conservative treatment protocols have not been properly documented.

Purpose: The aim of this study was to investigate the effect of a newly developed eccentric training program for patellar tendinopathy in volleyball players during the competitive season.

Study Design: Randomized clinical trial.

Methods: Patients were recruited from male and female elite volleyball teams in Norway, and the diagnosis was based on clinical examination alone. Of 51 players diagnosed with patellar tendinopathy, 29 could be included in the study. The training group (n = 13) performed squats on a 25° decline board as a home exercise program (3 × 15 repetitions twice daily) for a 12-week intervention period during the final half of the competitive season. The eccentric (downward) component was done on the affected leg. The control group (n = 16) trained as usual. The primary outcome was a symptom-based questionnaire developed specifically for patellar tendinopathy (Victorian Institute of Sport Assessment score), and patients were followed up before and after the intervention period, as well as after 6 and 30 weeks. All subjects self-recorded training to document their activity level (eccentric training, volleyball training, matches, other training).

Results: There was no change in Victorian Institute of Sport Assessment score during the intervention period in the training (pre, 71.1 ± 11.3; post, 70.2 ± 15.4) or control group (pre, 76.4 ± 12.1; post, 75.4 ± 16.7), nor was there any change during the follow-up period at 6 weeks or 6 months. The training group completed 8.2 ± 4.6 weekly sessions of eccentric training during the intervention period (59% of the recommended volume), and there was no difference between groups in training or competition load.

Conclusion: There was no effect on knee function from a 12-week program with eccentric training among a group of volleyball players with patellar tendinopathy who continued to train and compete during the treatment period. Whether the training would be effective if the patients did not participate in sports activity is not known.

Intertester reliability of sonography in patellar tendinopathy

Objective. Intertester reliability is imperative during the sonographic assessment of patellar tendinopathy because hypoechoic areas can change over time, and repeated examination may involve multiple examiners. Given that, to our knowledge, it has not been reported in the literature, the objective of this study was to investigate the intertester reliability of sonography for the detection and measurement of hypoechoic areas associated with patellar tendinopathy.

Methods. The study cohort comprised 8 patients with clinically diagnosed patellar tendinopathy and 4 patients with bilateral asymptomatic patellar tendons. Two equally experienced musculoskeletal radiologists imaged both patellar tendons from each patient (n = 24). All 24 tendons were assessed on the same day with the use of identical sonography machines.

Results. The radiologists had 100% chance-corrected agreement for detecting 12 normal (hypoechoic free) and 12 abnormal (hypoechoic) tendons. All measurement data were normally distributed (P > .05), and a range of hypoechoic area sizes was evident. No statistically significant differences were found for the measurements of hypoechoic area, axial plane height and width, and sagittal plane height (P > .05). In addition, these measurements were equally highly correlated (Pearson r > 0.87; P < .01).

Conclusions. The results reported in this study suggest that the intertester
reliability of sonography for the assessment of patellar tendinopathy is high. Although these results are encouraging, a small sample was analyzed, and this increases the probability of type II measurement error. Larger studies are therefore required to confirm these findings. High intertester reliability indicates that multiple experienced radiologists can reliably assess the same tendon and provides researchers with a necessary foundation for furthering research in tendon rehabilitation.

Discriminative ability of functional loading tests for adolescent jumper

Objective: To investigate the reliability and validity of five squat-based loading tests that are clinically appropriate for jumper's knee. The loading tests were step up, double leg squat, double leg squat on a 25-degree decline (decline squat), single leg decline squat, and decline hop. Design: Cross-sectional controlled cohort. Subjects without knee pain comprised controls, those with extensor tendon pain comprised the jumper's knee group. Setting: Institutional athlete study group in Australia. Participants: Fifty-six elite adolescent basketball players participated in this study, thirteen comprised the jumper's knee group, fifteen athletes formed a control group. Intervention: Each subject performed each loading test for baseline and reliability data on the first testing day. Subjects then performed three days of intensive (6 h daily) basketball training, after which each loading test was reexamined. Main outcome measures: Eleven point interval scale for pain. Results: The tests that best detected a change in pain due to intensive workload were the single leg decline squat and single leg decline hop. This study found that decline tests have better discriminative ability than the standard squat to detect change in jumper's knee pain due to intensive training. The typical error for these tests ranged from 0.3 to 0.5, however, caution should be exercised in the interpretation of these reliability figures due to relatively low scores. Conclusions: The single leg decline squat is recommended in the physical assessment of adolescent jumper's knee. The decline squat was selected as the best clinical test over the decline hop because it was easier to standardise performance.

Low-intensity pulsed ultrasound for chronic patellar tendinopathy : a randomized, double-blind, placebo-controlled trial

Objective. Patellar tendinopathy (PT) is a common and significant clinical condition for which there are few established interventions. One intervention that is currently being used clinically to manage PT symptoms is the introduction of low-intensity pulsed ultrasound (LIPUS). The aim of this study was to investigate the clinical efficacy of LIPUS in the management of PT symptoms.

Methods. A randomized, double-blind, placebo-controlled study was conducted. Volunteers with clinically and radiologically confirmed PT were randomly allocated to either an active-LIPUS (treatment) or inactive-LIPUS (placebo) group. LIPUS was self-administered by participants for 20 min/day, 7 days/week for 12 weeks. All participants also completed a daily, standardized eccentric exercise programme based on best practice. Primary outcomes were change in pain during the participant's most aggravating activity in the preceding week, measured on 10 cm visual analogue scales for both usual (VAS-U) and worst (VAS-W) tendon pain.

Results. Out of 156 individuals who volunteered, 37 met the eligibility criteria and were randomized to either active-LIPUS (n = 17) or inactive-LIPUS (n = 20). Using an intention-to-treat analysis, VAS-U and VAS-W for the entire cohort decreased by 1.6 ± 1.9 cm (P < 0.01) and 2.5 ± 2.4 cm (P < 0.01), respectively. There were no differences between the active- and inactive-LIPUS groups for change in VAS-U (–0.2 cm; 95% CI, –1.5, 1.1 cm) (P = 0.74) or VAS-W (–0.5 cm; 95% CI, –2.1, 1.1 cm) (P = 0.57). A per-protocol analysis provided similar results.

Conclusions. These findings suggest that LIPUS does not provide any additional benefit over and above placebo in the management of symptoms associated with PT.

Adiposity and tendinopathy

Purpose. Tendon injuries (tendinopathy) are prevalent across the population, affecting active and inactive individuals and manual workers. The aetiology of tendinopathy is not known. However, extrinsic factors such as load are known to affect the prevalence. More recently, intrinsic factors have been shown to also affect tendons; genes, biomechanics, and strength have been shown to influence tendon disease. One intrinsic factor that appears to have an association with tendinopathy is body composition; more specifically central adiposity. Several studies have reported this association, and several studies have found the association when reporting other aspects of tendinopathy.

Method. This paper will detail what is known about the association between tendinopathy and body composition, examine the strength of the association by evaluating studies in the area and speculate on potential mechanisms for the association.

Results. The association between tendon health and adiposity, especially central adiposity, warrants further investigation.

Conclusion. There may be an interaction between adiposity and tendon pathology. Adiposity may be a key intrinsic risk factor that is translated into tendon disease in the presence of additional intrinsic (e.g., diabetes) and extrinsic factors (e.g., load).