Neovascularity in patellar tendinopathy and the response to eccentric training: A case report using Power Doppler ultrasound

Resistance Training Interventions for Lower Limb Tendinopathies: A Scoping Review of Resistance Training Reporting Content, Quality, and Scientific Implementation

The objectives of this scoping review were as follows: (1) to describe what exercises and intervention variables are used in resistance training interventions for lower limb tendinopathy,  (2) to assess the completeness of reporting as assessed by the Consensus on Exercise Reporting Template (CERT) and the Toigo and Boutellier framework, and (3) to assess the implementation of scientific resistance training principles. We searched MEDLINE, CINAHL, AMED, Embase, SPORTDiscus, and Cochrane Library databases. Randomized controlled trials, cohort studies, case series, case reports, and observational studies that reported using resistance exercises for lower limb tendinopathies were considered for inclusion, with 194 studies meeting the inclusion criteria. Completeness of the reporting of exercise descriptors and programme variables was assessed by the CERT and the Toigo and Boutellier framework. Reporting of exercise descriptor items from the Toigo and Boutellier framework ranged from 0 to 13, with an average score of 9/13, with only 9 studies achieving a full 13/13. Reporting of items from the CERT ranged from 0 to 18, with an average score of 13/19. No study achieved a full 19/19; however, 8 achieved 18/19. Scoring for resistance training principles ranged from 1 to 10, with only 14 studies achieving 10/10. Eccentric heel-drops were the most common exercise (75 studies), followed by isotonic heel raises (38), and single-leg eccentric decline squats (27). The reporting of exercise descriptors and intervention content was high across studies, with most allowing exercise replication, particularly for Achilles and patellar tendinopathy. However, reporting for some tendinopathies and content items such as adherence was poor, limiting optimal translation to clinical practice.

Patellar tendon morphology in trans-tibial amputees utilizing a prosthesis with a patellar-tendon-bearing feature

A patellar-tendon-bearing (PTB) bar is a common design feature used in the socket of trans-tibial prostheses to place load on the pressure-tolerant tissue. As the patellar tendon in the residual limb is subjected to the perpendicular compressive force not commonly experienced in normal tendons, it is possible for tendon degeneration to occur over time. The purpose of this study was to compare patellar tendon morphology and neovascularity between the residual and intact limbs in trans-tibial amputees and healthy controls. Fifteen unilateral trans-tibial amputees who utilized a prosthesis with a PTB feature and 15 age- and sex- matched controls participated. Sonography was performed at the proximal, mid-, and distal portions of each patellar tendon. One-way ANOVAs were conducted to compare thickness and collagen fiber organization and a chi-square analysis was used to compare the presence of neovascularity between the three tendon groups. Compared to healthy controls, both tendons in the amputees exhibited increased thickness at the mid- and distal portions and a higher degree of collagen fiber disorganization. Furthermore, neovascularity was more common in the tendon of the residual limb. Our results suggest that the use of a prosthesis with a PTB feature contributes to morphological changes in bilateral patellar tendons.

COMPARISON OF FUNCTIONAL ACTIVITIES ON STRUCTURAL CHANGES OF THE INFERIOR PATELLAR POLE

Background

It is well known that eccentric and concentric exercise produce varied amounts of stress on the connective tissues. Diagnostic ultrasound has been used to measure these structural changes by observing fascicle length, angle, and thickness; however, there is a lack of evidence comparing the structural changes as it relates to eccentric, concentric, and stretching protocols.

Purpose

The purpose of this study was to compare the acute effects of static stretching, eccentric, concentric, and a combination of eccentric/concentric exercises on structural changes of the muscle tendon unit at the inferior patellar pole utilizing the diagnostic ultrasound.

Study Design

A repeated measures 2 × 4 within factorial study design with repeated measures on both factors was used to determine the differences in patellar tendon thickness within and between groups.

Methods

Forty-seven healthy subjects were screened for any lower extremity deficits or orthopaedic pathology. Forty-four (N=44) subjects completed all four protocols; the attrition was due to injuries to the lower extremity, occurring unrelated to the study. A baseline measurement of the anterior inferior patellar tendon was performed with the diagnostic ultrasound prior to each participant completing one of the four interventions per week over a four-week period. Interventions completed by each participant included static stretching, concentric, eccentric, and combined concentric and eccentric exercises. Immediately following each intervention, a post-intervention inferior patellar tendon measurement was recorded using the diagnostic ultrasound.

Results

Significant differences in anterior to posterior tendon thickness of the inferior patellar tendon were observed between pre (4.983 ± 0.041mm) and post (5.198 ± 0.055mm) measurements (p<0.0005) for the main effect of time. However, no differences in tendon thickness were noted comparing each intervention to one another (p=0.351).

Conclusion

Differences in tendon thickness were noted acutely for pre- to post measurements across all interventions. Further research is needed to determine if differences in tendon thickness exist with a longer duration of exercise over time and with different types of intervention.

Effects of eccentric overload training on patellar tendon and vastus lateralis in three days of consecutive running

BACKGROUND

The analysis of structural changes in patellar tendon and muscle of healthy subjects in response to mechanical loads provides useful insight into the mechanism underlying overuse injuries.

METHODS

Changes produced in tendon and muscles structures after eccentric overload training and three consecutive running days were examined. Twenty healthy subjects were recruited and divided into two groups. One group (ECC) performed eccentric overload squat training (six weeks). After such training, the ECC group performed three running sessions on consecutive days, as did the control group (CONT). The structure of their patellar tendons and vastus lateralis muscles was quantified using ultrasound and Doppler imaging. Images were obtained before and after eccentric training for the ECC group and on every day of running performance for both groups.

RESULTS

After eccentric training, the ECC group experienced an increase in cross-sectional area (CSA) of patellar tendon (P=0.012). After every day of running, the ECC group experienced a decrease in CSA (P=0.027). In the CONT group, after one day of running a significant increase was observed in anteroposterior width of their patellar tendon (P=0.028), as well as a decrease in pennation angle of vastus lateralis muscle (P=0.028) within three days of running sessions.

CONCLUSIONS

Eccentric overload training brought about changes in the patellar tendon consistent with an improvement in the quality of the tissue. The ECC group in our study showed a more normalised pattern than the CONT group in the running performance, in agreement with previous research.

LEVEL OF EVIDENCE

Level 3, controlled trial.

Causative factors and rehabilitation of patellar tendinopathy: A systematic review

Background

Patellar tendinopathy (PT) is a common chronic pathology of the knee, with a high prevalence in athletes and the general population.

Objectives

The objectives of this article were to systematically investigate all the evidence applicable to the intrinsic and extrinsic causative factors and rehabilitation of PT, and then integrate and link rehabilitation with the main causative factors identified.

Method

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Various tools were used to evaluate the methodological quality of the eligible articles. Data were interpreted descriptively, and the causative factors and rehabilitation of PT were analysed.

Results

Twenty studies were included in the review. The distinctive factor responsible for PT is the mechanical theory. Seven intrinsic and four extrinsic risk factors were identified, with the main intrinsic risk factors being muscle flexibility and strength, and extrinsic risk factors being acquisition and level of skills. PT can be treated with numerous different therapeutic modalities, although eccentric muscle training showed exceptional results. The intrinsic and extrinsic risk factors can only be transformed and reduced by rehabilitation, which is inevitable to improve PT pain and function.

Conclusion

The essence of an integrated management protocol for PT is to identify the dominant contributing factors, whether intrinsic or extrinsic, and to reduce the load on the patellar tendon by modifying these factors by either rehabilitation intervention or direct modification of the equipment or environment to obtain a positive outcome towards pain management and function.

Changes in water content in response to an acute bout of eccentric loading in a patellar tendon with a history of tendinopathy: A case report

OBJECTIVE

This case-based report assessed resting water content and exercise-driven water exchange within a tendon with a history of tendinopathy and compared the response to that of a healthy uninvolved tendon.

DESIGN

Case Report.

SETTING

University imaging center.

PARTICIPANT

The participant was a 27-year-old female basketball player 39 months following knee trauma. Patellar tendinopathy developed 12 months after the injury episode and was treated with eccentric exercises. Eighteen months from the beginning of the first eccentric training bout, the participant reported full resolution of symptoms and returned to her pre-injury sport participation without symptoms.

INTERVENTION

Eccentric decline squat exercise.

MAIN OUTCOME MEASURES

Tendon water content obtained from magnetic resonance imaging (MRI).

RESULTS

MRI acquired 39 months post-injury demonstrated increased resting water content of the involved tendon (involved: 91.1% vs. uninvolved: 84.6%). Immediately after the eccentric squat maneuver, water content decreased on both involved and uninvolved tendons (involved: 89.5% vs. uninvolved: 83.3%).

CONCLUSIONS

Elevated resting water content of the involved tendon found in this report may be indicative of reduced tendon stiffness. A similar amount of water content reduction was observed on both sides following mechanical loading, suggesting that the involved tendon may respond to the eccentric exercise similarly to the uninvolved tendon. Future investigations are needed to study the relationships among tendon water exchanges, mechanical properties, patient symptoms, and tissue injuries.

Rehabilitation of tendopathies in human athletes

Tendinopathies, chronic tendon disorders characterized by pain and functional impairment, are a common problem particularly in elite and recreational athletes. There is a high prevalence of Achilles tendinopathy in runners, while patellar tendinopathies, also referred to as jumpers knee, are very common amongst volleyball and basketball players. However, tendinopathies also occur in the sedentary population. The syndrome is associated with a variety of morphological, histopathological, biochemical and molecular changes, such as an increase in tendon cross sectional area, loss of fibre organization and infiltration of blood vessels. It has been shown that exercise or mechanical loading plays a role, which is why overuse is suspected to initiate tendinopathies. The exact mechanisms are still poorly understood, which makes the treatment problematic. A variety of treatment options are available, ranging from non-invasive procedures such as exercise treatment, topical nitroglycerin patches or shock wave therapy, over injections of various substances, such as corticosteroids, platelet-rich plasma or sclerosing agents, to surgical debridement. However, most of the treatment options focus solely on symptom relief, and the evidence for their effectiveness is often poor. The effectiveness of a treatment is furthermore likely to depend on the stage of the tendinapathy. In contrast to many therapies, exercise treatment has been relatively well investigated, has been shown to work in the majority of cases and is considered the gold standard.