Impact of Patellar Tendinopathy on Knee Proprioception: A Cross-Sectional Study

Relationship Between Postural Stability and Proprioception, Pain, Quadriceps Strength, and Muscle Tightness in Athletes With Patellar Tendinopathy

BACKGROUND

Athletes with patellar tendinopathy (PT) have postural stability deficits; however, the underlying mechanisms and factors responsible remain unknown. The effect on postural stability in PT of decreased quadriceps strength, altered proprioception, lower-limb muscle tightness, and knee pain, which explain postural stability deficiency in other populations, is uninvestigated.

HYPOTHESIS

Proprioceptive acuity, muscle tightness, quadriceps strength, and pain predict postural stability in athletes with PT.

STUDY DESIGN

Cross-sectional comparative study.

LEVEL OF EVIDENCE

Level 2.

METHODS

A total of 43 athletes with PT and 43 healthy athletes were enrolled. Static and dynamic postural stability, proprioceptive acuity, muscle tightness, quadriceps strength, and pain were evaluated using a force platform, Y-balance test (YBT), a weight discrimination protocol, a goniometer, an isometric dynamometer, and a valid questionnaire, respectively.

RESULTS

Athletes with PT had significantly worse static and dynamic postural stability in the affected limb (AL) compared with the nonaffected limb (NAL) (P < 0.01) and the control group (P < 0.01). Athletes suffering from PT revealed lower quadriceps strength (P < 0.01), proprioceptive acuity (P = 0.02), and higher muscle tightness in the AL compared with the NAL and controls. Quadriceps weakness of the AL and pain in athletes with PT explained the variance of dynamic postural stability impairment.

CONCLUSION

Athletes with PT have postural stability deficiency compared with healthy peers. Our results demonstrate that quadriceps muscle weakness and pain are the factors that explain postural stability impairment.

CLINICAL RELEVANCE

These results can assist clinicians in the design of therapeutic balance rehabilitation programs by acting not only on pain relief but also on quadriceps strengthening through resistance training to avoid subsequent injuries in athletes with PT.

Changes After a Conventional vs. an Alternative Therapy Program on Physical, Psychological, and Injury-Related Parameters in Male Youth Soccer Players With Patellar Tendinopathy During Return to Competition

ABSTRACT

Niering, M and Muehlbauer, T. Changes after a conventional vs. an alternative therapy program on physical, psychological and injury-related parameters in male youth soccer players with patellar tendinopathy during return to competition. J Strength Cond Res 37(9): 1834-1843, 2023-Changes after a conventional (CON) vs. alternative (ALT) therapy program on physical, psychological, and injury-related or pain-related parameters in soccer players with patellar tendinopathy (PT) during return to competition were examined. Thirty-four male youth soccer players (15-16 years) with PT were randomly assigned to a CON ( n = 18) or ALT ( n = 16) program. The ALT program consisted of 60 minutes of balance training, eccentric and isometric exercises, static stretching, and a dual-task progression. The CON program consisted of 30 minutes of eccentric and isometric exercises and static stretching. Both programs were conducted until painlessness was reported during full training load. Assessments of muscle power (drop jump, jump and reach), change of direction speed (CODS) (acyclic sprint), speed (tapping, 30-m linear sprint), endurance (Yo-Yo intermittent recovery test level-1), the Achievement Motives Scale Sport, and injury-related or pain-related correlates were performed immediately, 6 weeks, 16 weeks, and 20 weeks after the respective therapy program. Players in the ALT group required a shorter program duration (ALT: 47.1 ± 15.6 days, CON: 58.2 ± 24.6 days) and achieved the same (muscle power, speed, endurance) or greater (CODS) improvements in physical performances, the same enhancements in psychological measures (achievement motives), and better values for injury-related or pain-related correlates (injury incidence, pain-related training interruptions). Results indicate that both programs effectively improve relevant outcome parameters in players with PT. The ALT therapy is more time efficient than the CON therapy. Therapists should consider this multimodal training program for effective treatment of athletes to shorten their return to competition time and minimize the risk of secondary injuries.

Upper Limb Function but Not Proprioception is Impaired in Essential Tremor: A Between-Groups Study and Causal Mediation Analysis

Background

Essential tremor (ET) is characterized by abnormal oscillatory muscle activity and cerebellar involvement, factors that can lead to proprioceptive deficits, especially in active tasks. The present study aimed to quantify the severity of proprioceptive deficits in people with ET and estimate how these contribute to functional impairments.

Methods

Upper limb sensory, proprioceptive and motor function was assessed inindividuals with ET (n = 20) and healthy individuals (n = 22). To measure proprioceptive ability, participants discriminated the width of grasped objects and the weight of objects liftedwith the wrist extensors. Causal mediation analysis was used to estimate the extentthat impairments in upper limb function in ET was mediated by proprioceptive ability.

Results

Participants with ET had impaired upper limb function in all outcomes, and had greater postural and kinetic tremor. There were no differences between groups in proprioceptive discrimination of width (between-group mean difference [95% CI]: 0.32 mm [-0.23 to 0.87 mm]) or weight (-1.12 g [-7.31 to 5.07 g]). Causal mediation analysis showed the effect of ET on upper limb function was not mediated by proprioceptive ability.

Conclusions

Upper limb function but not proprioception was impaired in ET. The effect of ET on motor function was not mediated by proprioception. These results indicate that the central nervous system of people with ET is able to accommodate mild to moderate tremor in active proprioceptive tasks that rely primarily on afferent signals from muscle spindles.

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.

Patellar tendinopathy impairs postural control in athletes: A case-control study

OBJECTIVE

To compare postural control performance between athletes with and without patellar tendinopathy (PT).

DESIGN

Case-control study.

PARTICIPANTS

Fifty-eight athletes, 29 with PT (PT group: PTG) and 29 healthy ones (control group: CG).

MAIN OUTCOME MEASURES

Static and dynamic postural control were assessed with a force platform and the Y-Balance Test (Y-BT), respectively. Quadriceps strength of both limbs was evaluated using an isometric dynamometer.

RESULTS

The PTG exhibited significantly (p < 0.05) higher centre of pressure (CoP) values than the CG on the foam surface, and significantly lower (p < 0.001) anterior, posteromedial and posterolateral normalized reach distances, and composite score in dynamic postural control on the injured limb (IL) compared to non-injured limb (NIL) and dominant limb (DL) of the CG. The quadriceps muscle strength was significantly lower on the IL compared to the NIL (p < 0.01) and DL (p < 0.05) of the CG.

CONCLUSION

Athletes suffering from PT exhibited worse static and dynamic postural control compared to healthy peers. As players with PT frequently continue training despite their tendon pain, physiotherapists and clinicians should incorporate balance rehabilitation programs in the treatment of these players, not only to prevent further potential injuries but also to enhance sport performance.

Athletes with unilateral patellar tendinopathy have increased subsequent lower extremity musculoskeletal injury risk

This study aimed to investigate static and dynamic postural balance inter-limb asymmetries in athletes with unilateral patellar tendinopathy (UPT) and estimate subsequent lower extremity musculoskeletal injury risk compared to controls. Twenty-eight athletes with UPT were recruited. Twenty-eight healthy athletes served as controls. Static postural balance inter-limb asymmetry (symmetry index: SI) was assessed based on differences in the mean centre of pressure (CoP) velocity (CoP_v) values between the affected leg (AL) and non-affected leg (NAL) for the UPT group, and the dominant leg (DL) and non-dominant leg (NDL) for controls. Outcome variables were dynamic postural balance, assessed with inter-limb asymmetry using the Y Balance Test (YBT), and injury risk. In static balance, SI values were significantly (P<0.001) higher in the UPT group compared to controls. In dynamic balance, normalized inter-limb asymmetry values were also significantly higher in athletes with UPT compared to controls in anterior (P<0.001), posteromedial (P<0.001) and posterolateral (P<0.01) directions, and in the composite score (P<0.001). Furthermore, the incidence of sustaining a non-contact lower extremity injury during the follow-up period (10 months) was significantly higher (P<0.05) in the UPT group compared to controls. Athletes with UPT had postural balance inter-limb asymmetries. Moreover, they had increased subsequent lower extremity musculoskeletal injury risk compared to controls. Since most athletes with UPT continue to train and compete, adequate training and rehabilitation programmes should be implemented to prevent potential subsequent injury occurrence.

Sensory Processing in People With and Without Tendinopathy: A Systematic Review With Meta-analysis of Local, Regional, and Remote Sites in Upper- and Lower-Limb Conditions

OBJECTIVE

To synthesize results of somatosensory processing tests in people with upper- and lower-limb tendinopathy, compared to controls.

DESIGN

Systematic review with meta-analysis.

LITERATURE SEARCH

Four electronic databases (MEDLINE, CINAHL Plus, SPORTDiscus, and Embase) were searched.

STUDY SELECTION CRITERIA

Included studies measured a domain of sensory processing and compared a tendinopathy group to a healthy control group.

DATA SYNTHESIS

Meta-analysis was conducted for outcomes with homogeneous data from at least 2 studies. Upper- and lower-limb conditions were compared and outcomes were examined by measurement site (local, regional, or remote to location of pain).

RESULTS

Of the 30 studies included, 18 investigated lateral elbow tendinopathy. The most commonly assessed outcome measures were pressure pain threshold (PPT) and thermal pain threshold. There was moderate evidence for local and regional reduction of PPT in upper-limb tendinopathies, but not at remote sites. In lower-limb tendinopathies, there was conflicting evidence regarding reduced PPT at local sites and limited evidence of normal PPT at remote sites. There was moderate evidence of sensitization of thermal pain threshold at local sites in upper-limb tendinopathies and limited evidence of no difference in thermal pain threshold in lower-limb tendinopathies. Findings across other domains were variable.

CONCLUSION

Sensory processing was different between upper-limb tendinopathy and lower-limb tendinopathy. Upper-limb tendinopathies showed signs consistent with primary and secondary hyperalgesia, but lower-limb tendinopathies did not. There was mixed evidence for primary hyperalgesia and limited evidence against secondary hyperalgesia. J Orthop Sports Phys Ther 2021;51(1):12-26. doi:10.2519/jospt.2021.9417.

Deep Friction Massage in the Management of Patellar Tendinopathy in Athletes: Short-Term Clinical Outcomes

CONTEXT

Deep friction massage (DFM) is often used in the treatment of tendinopathies; however, the pressure applied may vary and interfere with the obtained results.

OBJECTIVE

To assess whether the immediate effects of DFM on pain (pain intensity and time to onset of analgesia) and muscle strength are dependent on the pressure applied during the DFM application in athletes with patellar tendinopathy.

DESIGN

Randomized, controlled, cross-over trial.

SETTING

University research laboratory (institutional).

PARTICIPANTS

Ten athletes with diagnosis of unilateral patellar tendinopathy (age 27.90 [5.24] y).

INTERVENTIONS

All participants attended 4 sessions, 3 treatment sessions with DFM applied with different pressures (the mean pressure-previously determined for each participant-and the mean pressure ± 25%) and a control session, each of which was separated by 48 hours.

MAIN OUTCOME MEASURES

Pain (intensity upon palpation and time to onset of analgesia), and muscle strength of knee extensors were assessed before and immediately after each session.

RESULTS

Pain intensity changed significantly over time (F1,9 = 52.364; P < .001; ηp2=.853) and among sessions (F3,27 = 82.588; P < .001; ηp2=.902), with a significant interaction for group × time (F3,27 = 19.841; P < .001; ηp2=.688). The knee extensors strength did not change significantly over time (F1,9 = 2.240; P = .17; ηp2=.199), nor a significant interaction for session × time was observed (F3,27 = 3.276; P = .07; ηp2=.267). Regardless of the pressure applied, the time to onset of analgesia was not significantly different (F2,18 = 1.026; P > .05; ηp2=.102).

CONCLUSION

It was shown that DFM induces an immediate reduction in pain intensity upon palpation, regardless of the pressure performed. Notwithstanding, the reader should take into account the small sample size and the caution needed in the results' interpretation.

High-energy dose of therapeutic ultrasound in the treatment of patellar tendinopathy: protocol of a randomized placebo-controlled clinical trial

BACKGROUND

Patellar tendinopathy is an extremely debilitating condition and its treatment usually requires a combination of clinical approaches. Therapeutic ultrasound (TUS) is one of the most available electrophysical agent in rehabilitation settings; however, there is also a lack of high-quality studies that test different dosimetric aspects of TUS. Thus, the purpose of this study is to evaluate the short-, medium-, and long-term effects of the combination of high-energy TUS with a rehabilitation program for patellar tendinopathy.

METHODS

This will be a randomized, placebo-controlled trial with blinding of patients, assessors, and therapist. The setting is an outpatient physical therapy clinic. We will recruit 66 participants (male and female) aged between 18 and 40 years and presenting with patellar tendinopathy. A treatment combining high-energy dose TUS and a rehabilitation program for patellar tendinopathy will be delivered twice a week for 8 weeks. The control group will receive the same treatment, but with a placebo TUS. The effectiveness of the intervention will be measured at the beginning (baseline), midpoint (4 weeks), and end of treatment (8 weeks), as well as at 3- and 6-months post-treatment. Primary outcomes will be pain intensity (visual analogue scale, VAS), and VISA-P questionnaire and primary time points will be baseline (T0) and the end of the program (T2). Also, IPAQ-short form questionnaire, muscle strength (manual dynamometry), 2D kinematics, pain pressure threshold (PPT) algometry, thermography, and magnetic resonance imaging (MRI) will be collected.

DISCUSSION

TUS will be applied in an attempt to enhance the results obtained with the rehabilitation program proposed in this study, as well as stimulate some repair responses in individuals undergoing treatment for patellar tendinopathy, which in turn may optimize and improve treatment programs for patellar tendinopathy as well as to establish new guidelines for the application of TUS.

TRIAL REGISTRATION

This study was prospectively registered at April-3rd-2018 and updated at September-1st-2019 in the Brazilian Registry of Clinical Trials (REBEC) under the registration number: RBR-658n6w.

Modifiable risk factors for patellar tendinopathy in athletes: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis identifying (1) potential modifiable risk factors and (2) associated modifiable factors for patellar tendinopathy in athletes.

DESIGN

A systematic review and meta-analysis was conducted. Risk of bias was assessed using the Newcastle-Ottawa Scale and grouped based on study design. Meta-analytic statistics were performed for items reported by five or more studies. A strength of evidence rating is provided for items not appropriate for meta-analysis.

DATA SOURCES

PubMed, Web of Science, Scopus and Cinahl were searched on 14 November 2017.

ELIGIBILITY CRITERIA

Quantitative, original research reporting potential modifiable risk factors or associated factors, comparing athletes with patellar tendinopathy with a group without the injury.

RESULTS

862 records were screened and 31 articles were included (6 prospective, 25 cross-sectional). There was a lack of strong evidence for any potential modifiable risk factor or associated factors. There was limited or conflicting evidence that decreased ankle dorsiflexion range of motion, decreased posterior thigh and quadriceps flexibility, greater volume of jump training, more volleyball sets played per week, greater countermovement jump (CMJ) height and greater activity volume are potential modifiable risk factors. Meta-analysis supported greater activity volume (Cohen's d=0.22, 95% CI 0.06 to 0.39, p=0.008), higher body weight (0.36, 0.17 to 0.55, p<0.001) and greater CMJ height (0.31, 0.07 to 0.56, p=0.01) as associated modifiable factors.

CONCLUSIONS

There is a lack of strong evidence for any potential modifiable risk factors or associated factors. Factors with lower levels of support may be of interest in designing prevention programmes but require further research in high-quality, prospective studies.

The relationship between acute pain and dynamic postural stability indices in individuals with patellar tendinopathy

BACKGROUND

Patellar tendinopathy is a common condition resulting in persistent pain, frequently reported during physical activity. The relationship between dynamic postural stability and pain in these individuals is unclear and how it may affect postural stability.

RESEARCH QUESTION

Is there a relationship between acute pain and dynamic postural stability indices in individuals with patellar tendinopathy?

METHODS

Twenty-two recreationally active individuals with patellar tendinopathy participated. Participants performed a two-legged jump and landed on a single test-limb on a force platform. They completed 100 mm visual analogue scales (VAS) before and after landing trials. Anterior-posterior (APSI), medial-lateral (MLSI), vertical (VSI), and composite (DPSI) stability indices were calculated from ground reaction force data. The relationship between stability indices and VAS for pain as well as pain change scores were assessed via non-parametric Spearman's rho (ρ) rank correlations (p≤.05).

RESULTS

Baseline pain was not significantly correlated with any stability indices. Post-landing pain was significantly correlated with MLSI (ρ = 0.540, p = 0.004) while, VSI (ρ = 0.353, p = 0.053) and DPSI (ρ = 0.347, p = 0.057) had moderate, yet insignificant correlations. Pain change scores demonstrated a large correlation with MLSI (ρ = 0.598, p = 0.002).

SIGNIFICANCE

As pain increased in individuals with patellar tendinopathy, dynamic postural stability indices values increased, indicating more difficulty transitioning from a dynamic to static state. Although balance deficits are not typically associated with patellar tendinopathy, it appears pain and dynamic postural stability may be related in these individuals.

Biomechanical Responses and Injury Characteristics of Knee Joints under Longitudinal Impacts of Different Velocities

Background and Objective

Knee joint collision injuries occur frequently in military and civilian scenarios, but there are few studies assessing longitudinal impacts on knee joints. In this study, the mechanical responses and damage characteristics of knee longitudinal collisions were investigated by finite element analysis and human knee impact tests.

Materials and methods

Based on a biocollision test plateau, longitudinal impact experiments were performed on 4 human knee joints (2 in the left knee and 2 in the right knee) to measure the impact force and stress response of the bone. And then a finite element model of knee joint was established from the Chinese Visible Human (CVH), with which longitudinal impacts to the knee joint were simulated, in which the stress response was determined. The injury response of the knee joint-sustained longitudinal impacts was analyzed from both the experimental model and finite element analysis.

Results

The impact experiments and finite element simulation found that low-speed impact mainly led to medial injuries and high-speed impact led to both medial and lateral injuries. In the knee joint impact experiment, the peak flexion angles were 13.8° ± 1.2, 30.2° ± 5.1, and 92.9° ± 5.45 and the angular velocities were 344.2 ± 30.8 rad/s, 1510.8 ± 252.5 rad/s, and 9290 ± 545 rad/s at impact velocities 2.5 km/h, 5 km/h, and 8 km/h, respectively. When the impact velocity was 8 km/h, 1 knee had a femoral condylar fracture and 3 knees had medial tibial plateau fractures or collapse fractures. The finite element simulation of knee joints found that medial cortical bone stress appeared earlier than the lateral peak and that the medial bone stress concentration was more obvious when the knee was longitudinally impacted.

Conclusion

Both the experiment and FE model confirmed that the biomechanical characteristics of the injured femur and medial tibia are likely to be damaged in a longitudinal impact, which is of great significance for the prevention and treatment of longitudinal impact injuries of the knee joint.

Men with unilateral Achilles tendinopathy have impaired balance on the symptomatic side

OBJECTIVES

To investigate single leg standing balance in males with mid-portion Achilles tendinopathy (AT).

DESIGN

Cross sectional case study.

METHODS

Centre of pressure (COP) path length was measured using a Wii Balance Board (WBB) in 21 male participants (20-60 years) with unilateral mid-portion AT during single-limb standing on each limb with eyes open and closed. Ultrasound imaging of both Achilles tendons was also performed by one blinded assessor, and the anteroposterior (AP) thickness and presence of pathology was determined. Comparisons were made between symptomatic and asymptomatic sides for key outcomes, and correlation between COP path length and variables of interest were investigated.

RESULTS

Symptomatic Achilles tendons demonstrated significantly increased AP tendon thickness (p<0.001). Participants with AT demonstrated increased COP path length (sway amplitude) on their affected side during the eyes closed task (p=0.001). Increased tendon thickness was associated with increased sway amplitude during the eyes open task on both the affected (rho=0.44, p=0.045) and unaffected sides (rho=0.62, p=0.003).

CONCLUSIONS

In males with AT, single-leg standing balance with eyes closed is impaired on the symptomatic side. This indicates that neuromuscular deficits affecting functional ability may be present in people with AT during more challenging balance activities. It is unclear if this deficit precedes the onset of symptoms, or is a consequence of tendon pain. Work is now needed to understand the mechanisms that may explain standing balance deficits among people with AT.

[Effect of electroacupuncture on proprioception in cynomolgus monkeys after unilateral anterior cruciate ligament injury]

OBJECTIVE

To study the effect of electroacupuncture on proprioception in cynomolgus monkeys after unilateral anterior cruciate ligament (ACL) injury.

METHODS

Twenty-seven cynomolgus monkeys were randomized equally into 3 groups, namely unilateral ACL injury with electroacupuncture group, unilateral ACL injury model group and blank control group. One week after modeling, the monkeys in electroacupuncture group were treated daily for 12 weeks with electroacupuncture at the acupoints Wei Yang, Yin Gu, Xi Yangguan and Qu Quan. At 4, 8, and 12 weeks during the treatment, the changes in the somatosensory evoked potentials (SEPs) and motor nerve conduction velocity (MCV) of the nerves of the ACL were examined with neural electrophysiological method; the changes in the morphology and the total and variable number of the proprioceptors in the ACL were observed with gold chloride staining. RESULTS; In the mokeys in the model group, the incubation period of the SEPs and MCV on the injured side of the knee were significantly extended and the amplitudes were decreased with the passage of time (P<0.05). Intervention with electroacupuncture significantly reduced the incubation period and increased the amplitudes of the SEPs and MCV (P<0.05). The total number of the proprioceptors in the ACL was significantly decreased and the variable number of the proprioceptors in ACL was increased with time in the monkeys in the model group (P<0.05); electroacupuncture intervention obviously slowed the reduction rate of total number of the proprioceptors (P<0.05) but without affecting the variable number of the proprioceptors (P>0.05). CoONCLUSION: ACL injury causes attenuation of the proprioception on the injury side, and electroacupuncture intervention can produce a positive effect on the proprioception in cynomolgus monkeys.