Lower Extremity Kinematics During a Drop Jump in Individuals With Patellar Tendinopathy

Knee joint biomechanics and cartilage damage prediction during landing: A hybrid MD-FE-musculoskeletal modeling

Understanding the mechanics behind knee joint injuries and providing appropriate treatment is crucial for improving physical function, quality of life, and employability. In this study, we used a hybrid molecular dynamics-finite element-musculoskeletal model to determine the level of loads the knee can withstand when landing from different heights (20, 40, 60 cm), including the height at which cartilage damage occurs. The model was driven by kinematics-kinetics data of asymptomatic subjects at the peak loading instance of drop landing. Our analysis revealed that as landing height increased, the forces on the knee joint also increased, particularly in the vastus muscles and medial gastrocnemius. The patellar tendon experienced more stress than other ligaments, and the medial plateau supported most of the tibial cartilage contact forces and stresses. The load was mostly transmitted through cartilage-cartilage interaction and increased with landing height. The critical height of 126 cm, at which cartilage damage was initiated, was determined by extrapolating the collected data using an iterative approach. Damage initiation and propagation were mainly located in the superficial layers of the tibiofemoral and patellofemoral cartilage. Finally, this study provides valuable insights into the mechanisms of landing-associated cartilage damage and could help limit joint injuries and improve training programs.

The influence of isolated femur and tibia rotations on patellar tendon stress: A sensitivity analysis using finite element analysis

The purpose of this study was to determine the influence of frontal and transverse plane rotations of the femur and tibia on peak maximum principal stress in the patellar tendon. Using finite element modeling, patellar tendon stress profiles of eight healthy individuals were obtained during a simulated squatting task (45° of knee flexion). The femur and tibia of each model were rotated 10° (in 2° increments) along their respective axes beyond that of the natural degree of rotation. This process was repeated for the transverse plane (internal and external rotation) and frontal plane (adduction and abduction). Quasi-static loading simulations were performed to quantify peak maximum principal stress in patellar tendon. Internal and external rotations of the femur and tibia that exceeded 4° beyond that of the natural rotation resulted in progressively greater patellar tendon stress (p < 0.05). Incremental femur and tibia adduction and abduction resulted in an increase in patellar tendon stress, but only at the end range of motions evaluated. These results suggest that tibiofemoral rotations in the frontal and transverse planes have the potential to influence patellar tendon stress. In particular, patellar tendon stress is highly sensitive to small degrees of tibia and/or femur motions in the transverse plane.

Relationship between Muscle-Tendon Stiffness and Drop Jump Performance in Young Male Basketball Players during Developmental Stages

BACKGROUND

The relationship between stiffness and drop jump performance in athletes in various stages of development has yet to be fully investigated. The first aim of this study was to investigate the association between the stiffness of the patellar and quadriceps tendon (PT, QT), gastrocnemius-Achilles tendon unit (GAT), and rectus femoris (RF) using drop jump (DJ) performance in young basketball players. The second aim was to investigate possible variations in the stiffness levels of those tissues in different developmental stages.

METHODS

The stiffness levels of the GAT, PT, QT, and RF were measured in both limbs in 73 male basketball players aged 12 to 18 years. The reactive strength index (RSI), contact time (CT) and jump height (JH) during 30 and 40 cm DJs were also measured.

RESULTS

Pearson correlation coefficients showed a significant association between DJ performance and PT, QT, GAT, and RF dynamic stiffness. Moreover, the youngest subjects were found to have lower stiffness values than the older ones.

CONCLUSIONS

Tissue stiffness can affect athletic performance by modifying the stretch-shortening cycle in young basketball players. Stiffness of muscles and tendons increases during the maturation process. Further investigations could shed light on the effect of training on the stiffness of muscles and tendons.

Preventive effect of tailored exercises on patellar tendinopathy in elite youth athletes: A cohort study

OBJECTIVE

To investigate the effects of an intervention with tailored exercises on the incidence of patellar tendinopathy (PT) in elite youth jumping athletes.

DESIGN

Prospective crossover cohort.

SETTING

One sport club facility.

PARTICIPANTS

271 elite youth basketball and volleyball player were followed in the first year of the study (Observation year) and 270 athletes were followed in the second year (intervention year).

MAIN OUTCOME MEASURE

Incidence rates of PT per 1,000h of exposure. Cox survival analysis was used to verify the effects of the intervention (exercises implemented according to the findings of a preseason assessment) on PT incidence.

RESULTS

The exercise prevention program significantly reduced the number of cases of PT, with athletes submitted to the intervention showing 51% less risk of developing PT. The overall PT incidence in the Observation year (5.9 per 1,000h of exposure) was significantly higher than that in the intervention year (2.8 per 1,000h of exposure) (P = .037). Twenty-six athletes developed PT in the observation year, whereas 13 athletes developed PT in the intervention year.

CONCLUSIONS

A tailored preventive program may be able to reduce the incidence of patellar tendinopathy, especially in male youth volleyball athletes. Randomized controlled trials are encouraged to confirm these findings.

Current Clinical Concepts: Clinical Management of Patellar Tendinopathy

Patellar tendinopathy is a common, yet misunderstood pathoetiology afflicting a variety of patient populations. This lack of unified understanding affects the capability of clinicians to provide effective treatment interventions. Patients with tendinopathy often report long-term and low to moderate levels of pain, diminished flexibility, and strength, as well as decreased physical function. Load-management strategies combined with exercise regimens focused on progressive tendon loading are the most effective treatment option for patients with patellar tendinopathy. This review will provide an evidence-based approach to patellar tendinopathy, including its pathoetiology, evaluation, and treatment strategies.

Are Landing Patterns in Jumping Athletes Associated with Patellar Tendinopathy? A Systematic Review with Evidence Gap Map and Meta-analysis

Background

Patellar tendinopathy (PT) is common and debilitating for jumping athletes. Intriguingly, despite its high prevalence and many research studies, a causal explanation for PT presence remains elusive.

Objective

Our objective was to investigate whether landing biomechanics among jumping athletes are associated with PT and can predict onset.

Methods

We conducted a systematic review with evidence gap map and meta-analysis. We searched three databases from inception to May 2021 for observational studies or trials evaluating landing biomechanics in jumping athletes with PT (JPTs). We assessed quality with a modified Downs and Black checklist, risk of bias with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool, and evidence levels with van Tulder’s criteria and provided an evidence gap map.

Results

One prospective cohort (moderate quality), one cross-sectional cohort (moderate quality), and 14 case–control (four high-, seven moderate-, and three low-quality) studies, including 104 JPTs, 14 with previous PT, 45 with asymptomatic patellar tendon abnormality (PTA), and 190 controls were retained. All studies had a high risk of bias. Meta-analysis showed an association between lower ankle dorsiflexion and the presence of tendinopathy during drop and spike landings, and JPTs had reduced knee joint power and work during volleyball approach or drop landings (moderate evidence). Limited evidence suggested that JPTs had lower patellar tendon loads during drop landings. Strong or moderate evidence showed no relation between PT and sagittal plane peak knee and hip angles or range of motion; hip, knee, or ankle angles at initial contact (IC); knee angular velocities, peak trunk kinematics, or trunk angles at IC; sagittal plane hip, knee, or ankle moments; and peak vertical ground reaction force (vGRF) and vGRF impulse. Identified gaps were that no study simultaneously investigated athletes with previous PT, current PT, and PTA, and studies of joint angular velocities at IC, ankle and hip angular velocities after touchdown, leg stiffness, loading rate of forces, and muscle activation are lacking.

Conclusion

Despite the voluminous literature, large number of participants, multitude of investigated parameters, and consistent research focus on landing biomechanics, only a few associations can be identified, such as reduced ankle dorsiflexion–plantarflexion range. Further, the quality of the existing literature is inadequate to draw strong conclusions, with only four high-quality papers being found. We were unable to determine biomechanical factors that predicted PT onset, as longitudinal/prospective studies enabling causal inference are absent. The identified gaps indicate useful areas in which to explore causal relationships to inform intervention development. Therefore, high-quality prospective studies are essential to definitively determine whether landing biomechanics play a part in the development, recurrence, or management of PT and represent a potential therapeutic or preventive target alongside non-biomechanical factors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01550-6.

Differences in Biomechanical Loading Magnitude During a Landing Task in Male Athletes with and without Patellar Tendinopathy

CONTEXT

Prior research has not established if overloading or underloading movement profiles are present in symptomatic and asymptomatic athletes with patellar tendon structural abnormality (PTA) compared to healthy athletes.

OBJECTIVE

The purpose was to compare involved limb landing biomechanics between male athletes with and without patellar tendinopathy.

DESIGN

Cross-sectional study Setting: Laboratory Patients or Other Participants: 43 males were grouped based on patellar tendon pain & ultrasound imaging of the proximal patellar tendon: symptomatic with PTA (SYM-PTA; n=13; 20±2yrs; 1.8±0.1m; 84±5kg), asymptomatic with PTA (ASYM-PTA; n=15; 21±2yrs; 1.8±0.1m; 82±13kg), and healthy control (CON; n=15; 20±2yrs; 1.8±0.1m; 79±12kg).

MAIN OUTCOME MEASURES

3D biomechanics were collected during double-limb jump-landing. Kinematic (knee flexion angle (KF)) and kinetic (vertical ground reaction force (VGRF); internal knee extension moment (KEM); patellar tendon force (FPT)) variables were analyzed as continuous waveforms during the stance phase for the involved limb. Mean values were calculated for each 1% of stance, normalized over 202 data points (0-100%), and plotted with 95% confidence intervals. Statistical significance was defined as a lack of 95% CI overlap for ≥ 6 consecutive data points.

RESULTS

SYM-PTA had lesser KF than CON throughout the stance phase. ASYM-PTA had lesser KF than CON in the early and late stance phase. SYM-PTA group had lesser KEM and FPT than CON in early stance, as well as ASYM-PTA in mid-stance.

CONCLUSIONS

Male athletes with SYM-PTA demonstrated a patellar tendon load-avoidance profile compared to ASYM-PTA and CON athletes. ASYM-PTA did not show evidence of overloading compared to CON. Our findings support the need for individualized treatments for athletes with tendinopathy to maximize load-capacity.

TRIAL REGISTRY

ClinicalTrials.gov (#XXX).

Efficacy of Kinesio Taping and McConnell Taping Techniques in the Management of Anterior Knee Pain

CONTEXT

Anterior knee pain also known as patellofemoral pain syndrome is a frequently encountered musculoskeletal disorder that worsens with activity. The multifactorial etiology of patellofemoral pain syndrome alters lower-extremity mechanics, increasing patellofemoral joint stresses during weight-bearing tasks. Kinesio and McConnell tapings are often incorporated into the treatment, but their efficacy is still unclear.

OBJECTIVE

To test the efficacy of Kinesio taping, McConnell taping, and sham taping in improving knee mechanics and reducing pain during activity.

DESIGN

Cross-sectional design.

SETTING

Clinical biomechanics laboratory.

PARTICIPANTS

Ten participants (age: 20.3 [1.5] y, height: 169.9 [10.4] cm, and mass: 70.17 [13.1] kg) with anterior knee pain and no history of trauma.

INTERVENTION

Three trials each of squat, drop jump, and step-down tasks with 3 taping conditions in a counterbalanced order.

MAIN OUTCOME MEASURES

Two-dimensional motion capture data of lower-extremities in frontal and sagittal planes were recorded and analyzed using 3 iPads and Spark Motion® application. Pooled effect sizes (Hedges' g), 95% confidence intervals, and repeated-measures analysis of variance (P < .05) compared baseline and taping conditions during exercises for pain Visual Analog Scale and knee flexion in all exercises, hip abduction during step-down and drop jump, frontal plane projection during step-downs, and knee translation in sagittal plane during squats.

RESULTS

Significant reductions in Visual Analog Scale were recorded during squats between tapes (F2.505,12.867 = 3.407, P = .04, Hedges' g = -0.70). Pairwise comparison showed a decrease in Visual Analog Scale for sham taping (mean difference = 1.14 cm, P = .01) and Kinesio taping (mean difference = 1.54 cm, P = .02) compared with baseline during squats.

CONCLUSIONS

A variety of taping methods can potentially reduce perceived pain in individuals with patellofemoral pain syndrome, allowing clinicians to perform rehabilitation exercises. Sensory effects associated with short-term taping may be sufficient enough to modify knee pain acutely by afferent input blocking nocioceptive pain before the participants could adapt. Most interestingly, the sham taping technique demonstrated promise for enhancing functional outcomes, depending on the length of the tape and area covered.

Relationship of Patellofemoral Angles and Tibiofemoral Rotational Angles With Jumper's Knee in Professional Dancers: An MRI Analysis

Background:

Jumper’s knee is a type of tendinopathy affecting the distal insertion of the quadriceps tendon (25% of cases) or the patellar tendon. It has been shown that frontal-plane measurements, such as genu valgum, genu varum, an increased quadriceps angle, a protuberant tibial tuberosity, patella alta, and short hamstring muscles, may be related to jumper’s knee.

Purpose:

To investigate the effects of tibiofemoral rotational angles and patellofemoral (PF) angles on the development of jumper’s knee in professional folk dancers.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

We examined 26 dancers (16 male, 10 female) with knee pain using magnetic resonance imaging (MRI), for a total of 32 knees. Of the knees, 21 with quadriceps tendinopathy (QT) and 7 with patellar tendinopathy (PT) were detected. Using MRI scans, we measured PF angles (PF sulcus angle, lateral PF angle, patellar tilt angle, lateral trochlear inclination angle, lateral patellar tilt angle, and PF congruence angle) and tibiofemoral rotational angles (condylar twist angle, posterior condylar angle, femoral Insall angle, tibial Insall angle, posterior tibiofemoral angle, and angle between the Whiteside line and posterior femoral condylar line) and noted specifics such as patella alta, patella baja, and the Wiberg classification of the patellar shape between the patients with versus without QT and between patients with versus without PT to understand if there was any relationship with tendinopathy.

Results:

No statistically significant difference was observed in age, sex, patella alta, or the Wiberg classification between the QT groups (with vs without) and between the PT groups (with vs without) (P > .05). Having QT was found to be significantly associated with the PF sulcus angle (P = .009), and having PT was found to be significantly associated with the femoral Insall angle (P = .029).

Conclusion:

Jumper’s knee was found to be associated with anatomic variations of the PF sulcus angle and rotation of the patellar tendon in relation to the femur (femoral Insall angle) on axial MRI scans in professional dancers. Unlike those of other athletes, dancers’ knees are exposed more to external rotation forces because of turnout, and this can be the cause of jumper’s knee.

Effects of Tissue Flossing and Dynamic Stretching on Hamstring Muscles Function

Tissue flossing aims to improve range of motion (ROM), reduce pain, and enhance injury prevention. However, evidence is lacking regarding its effects. Therefore, this study examined the effects of flossing on hamstring muscles function in comparison to dynamic stretching (DS). Seventeen healthy young men ([mean ± SD] age, 23.2 ± 1.1 years; height, 1.72 ± 0.08 m; body mass, 63.5 ± 9.3 kg) volunteered as subjects in this randomized crossover trial. The subjects received flossing, DS, and control interventions in random order at least 1 week apart to eliminate the influence of the previous intervention. Flossing involved passive twisting and active movement using a floss band (Sanctband COMPRE Floss Blueberry, Sanct Japan Co., Ltd.). DS was performed for 4 minutes in 30-second sets consisting of 15 repetitions of 2 seconds stretching. The following were measured before and after each intervention: straight leg raise (SLR) test, passive knee extension (KE) test, passive torque, passive stiffness, fascicle length in the biceps femoris long head as an indication of hamstring muscles flexibility, and maximal isometric knee flexion contraction, maximal eccentric knee extension/flexion contraction, rate of force development, and muscle activity. Flossing yielded significant improvements in the SLR test (mean difference in post-intervention changes between interventions: 5.4°, percentage change from pre- to post-value: 13.4%, p = 0.004), passive KE test (6.2°, 4.5%, p < 0.001), passive torque at end-ROM (3.8 Nm, 4.7%, p = 0.03), and maximal eccentric knee flexion contraction (14.9% body weight, 8.2%, p = 0.03) than control. Moreover, flossing yielded 2.1-fold greater improvements in the passive KE test (3.8°, 4.5%, p = 0.03) and yielded significant improvements in the maximal eccentric knee extension contraction (29.9% body weight, 13.8%, p = 0.02) than DS. Therefore, flossing on hamstring muscles is more beneficial than DS with respect to increasing ROM and muscle exertion.

Landing biomechanics are not immediately altered by a single-dose patellar tendon isometric exercise protocol in male athletes with patellar tendinopathy: A single-blinded randomized cross-over trial

OBJECTIVES

To a) determine the acute effects of a single-dose patellar tendon isometric exercise protocol on involved limb landing biomechanics in individuals with patellar tendinopathy and asymptomatic patellar tendon pathology, and b) determine if individuals with patellar tendinopathy demonstrated changes in pain following a single-dose patellar tendon isometric exercise protocol.

DESIGN

Single-blinded randomized cross-over trial.

SETTING

Laboratory; PARTICIPANTS: 28 young male athletes with symptomatic (n = 13, age: 19.62 ± 1.61) and asymptomatic (n = 15, age: 21.13 ± 1.88) patellar tendinopathy.

MAIN OUTCOME MEASURES

Participants completed a single-dose patellar tendon isometric exercise protocol and a sham-TENS protocol, randomized and separated by 7-10 days. Pain-levels during a single-limb decline squat (SLDS) and three-dimensional biomechanics were collected during a double-limb jump-landing task before and after each intervention protocol. A mixed-model repeated measures ANOVA was conducted to compare change scores for all dependent variables.

RESULTS

There were no group × intervention interactions for change in pain (F_{(1, 26)} = 0.555, p = 0.463). There was one significant group × intervention interaction for vertical ground reaction force (VGRF) (F_{(1, 26)} = 5.33, p = 0.029). However, post-hoc testing with Bonferroni correction demonstrated no statistical significance for group (SYM: t = -1.679, p = 0.119; ASYM: t = -1.7, p = 0.107) or intervention condition (isometric: t = -2.58, p = 0.016; sham-TENS: 0.72, p = 0.460). There were no further significant group × intervention interactions (p > 0.05).

CONCLUSIONS

A single-dose patellar tendon isometric exercise protocol did not have acute effects on landing biomechanics or pain levels in male athletes with patellar tendinopathy or asymptomatic patellar tendon pathology.

Thirty-seven jump-landing biomechanical variables are associated with asymptomatic patellar tendon abnormality and patellar tendinopathy: A systematic review

OBJECTIVE

To identify studies that report three-dimensional (3D) biomechanical analysis of jump-landing tasks in relation to athletes with current patellar tendinopathy (PT), and/or asymptomatic with history of PT or patellar tendon abnormality (PTA) on diagnostic imaging.

METHODS

Five electronic databases were searched. Included articles were required to: (1) investigate the 3D biomechanics of a jump-landing task; (2) be cross-sectional or longitudinal in design; and (3) include participants that had symptomatic PT, were asymptomatic with a history of PT, asymptomatic with PTA on diagnostic imaging and/or asymptomatic with an unknown pathology or PT history.

RESULTS

Thirty-seven statistically significant jump-landing variables were associated with PT, history of PT and/or PTA. The only consistent variable that could be replicated between studies was knee flexion angle at initial foot-ground contact (IC) and an altered hip flexion/extension strategy during a horizontal land phase of a vertical stop-jump.

CONCLUSION

Isolated vertical landings or take-offs alone may not be sensitive enough to identify key jump-landing variables associated with PT, thus clinicians and researchers should incorporate a whole jump-landing task with a horizontal landing component. Sagital plane hip and knee kinematics in a horizontal landing phase appear to provide the most valuable information for evaluating those with PT.

Clinical Measures and Their Contribution to Dysfunction in Individuals With Patellar Tendinopathy

CONTEXT

Patellar tendinopathy (PT) is prevalent in physically active populations, and it affects their quality of living, performance of activity, and may contribute to the early cessation of their athletic careers. A number of previous studies have identified contributing factors for PT; however, their contributions to self-reported dysfunction remain unclear.

OBJECTIVE

The purpose of this investigation was to determine if strength, flexibility, and various lower-extremity static alignments contributed to self-reported function and influence the severity of PT.

DESIGN

Cross-sectional research design.

SETTING

University laboratory.

PARTICIPANTS

A total of 30 participants with PT volunteered for this study (age: 23.4 [3.6] y, height: 1.8 [0.1] m, mass: 80.0 [20.3] kg, body mass index: 25.7 [4.3]).

MAIN OUTCOME MEASURES

Participants completed 7 different patient-reported outcomes. Isometric knee extension and flexion strength, hamstring flexibility and alignment measures of rearfoot angle, navicular drop, tibial torsion, q-angle, genu recurvatum, pelvic tilt, and leg length differences were assessed. Pearson's correlation coefficients were assessed to determine significantly correlated outcome variables with each of the patient-reported outcomes. The factors with the highest correlations were used to identify factors that contribute the most to pain and dysfunction using backward selection, linear regression models.

RESULTS

Correlation analysis found significant relationships between questionnaires and body mass index (r = -.35-.46), normalized knee extension (r = .38-.50) and flexion strength (r = -.34-.50), flexibility (r = .32-.38, q-angle (r = .38-.56), and pelvic tilt (r = -.40). Regression models (R² = .22-.54) identified thigh musculature strength and supine q-angle to have greatest predictability for severity in patient-reported outcomes.

CONCLUSIONS

These findings put an emphasis of bodyweight management, improving knee extensor and flexor strength, and posterior flexibility in PT patients.

Effects of Exercise-Induced Fatigue on Lower Extremity Joint Mechanics, Stiffness, and Energy Absorption during Landings

The aim of this study was to determine the effects of two fatigue protocols on lower-limb joint mechanics, stiffness and energy absorption during drop landings. Fifteen male athletes completed landing tasks before and after two fatigue protocols (constant speed running [R-FP] and repeated shuttle sprint plus vertical jump [SJ-FP]). Sagittal plane lower-limb kinematics and ground reaction forces were recorded. Compared with R-FP, SJ-FP required significantly less intervention time to produce a fatigue state. The ranges of motion (RoM) of the hip were significantly greater when the athletes were fatigued for both protocols. Knee RoM significantly increased after SJ-FP but not after R-FP (p > 0.05), whereas the RoM of the ankle was significantly greater after R-FP but lower after SJ-FP. When fatigued, the first peak knee extension moment was significantly greater in R-FP but lower in SJ-FP; the second peak ankle plantar flexion moment was lower, regardless of protocols. After fatigue, vertical, hip, and knee stiffness was lower, and more energy was absorbed at the hip and knee for both protocols. Hip and knee extensors played a crucial role in altering movement control strategies to maintain similar impact forces and to dissipate more energy through a flexed landing posture when fatigued compared to when non-fatigued. Furthermore, SJ-FP seems to be a more efficient method to induce fatigue due to less intervention time than R-FP.

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.

Association of Hip and Foot Factors With Patellar Tendinopathy (Jumper's Knee) in Athletes

Background Investigations on the causes of patellar tendinopathy should consider impairments at the hip and foot/ankle because they are known to influence movement patterns and affect patellar tendon loading. Objectives To investigate hip and foot/ankle impairments associated with patellar tendinopathy in volleyball and basketball athletes using classification and regression tree analysis. Methods In this clinical measurement, cross-sectional study, 192 athletes were assessed for impairments of the hip and foot/ankle, including shank-forefoot alignment, dorsiflexion range of motion (ROM), iliotibial band flexibility, passive hip internal rotation ROM, and hip external rotator and hip abductor isometric strength. Athletes with tenderness and/or pain at the inferior pole of the patella were considered to have patellar tendinopathy. Athletes with scores higher than 95 points on the Victorian Institute of Sport Assessment-patella (VISA-P), no pain during the single-leg decline squat, and no history of patellar tendon pain were considered not to have patellar tendinopathy. Classification and regression tree analyses were performed to identify interacting factors associated with patellar tendinopathy. Results Interactions among passive hip internal rotation ROM, shank-forefoot alignment, and hip external rotator and abductor strength identified athletes with and without patellar tendinopathy. The model achieved 71.2% sensitivity and 74.4% specificity. The area under the receiver operating characteristic curve was 0.77 (95% confidence interval: 0.70, 0.84; P<.001). Conclusion Impairments of the hip and foot/ankle are associated with the presence of patellar tendinopathy in volleyball and basketball athletes. Future studies should evaluate the role of these impairments in the etiology of patellar tendinopathy. J Orthop Sports Phys Ther 2018;48(9):676-684. Epub 23 May 2018. doi:10.2519/jospt.2018.7426.

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.

Isometric strength of the hip abductors and external rotators in athletes with and without patellar tendinopathy

PURPOSE

This study aims to compare the isometric strength of hip abductors and external rotators in male athletes with and without patellar tendinopathy (PT), and to examine the correlation between hip strength, pain, and functional scores.

METHODS

Sixty male athletes (30 with PT and 30 controls) were recruited from local volleyball and basketball teams. The isometric strength of the hip abductors and external rotators was quantified using a belt-stabilized handheld dynamometer. This study used the visual analog scale (VAS) and the Victorian Institute of Sport Assessment-Patella (VISA-p) questionnaire to measure the intensity of pain and functional scores in athletes with PT, respectively.

RESULTS

The normalized isometric strength of the hip abductors and external rotators was significantly less in the PT group compared with controls. In subjects with PT, the normalized isometric strength was decreased by 22.0% (p = 0.000) in the hip abductors and by 20.0% in the hip external rotators (p = 0.004), compared with controls. Significant correlations were found between the normalized isometric strength of the hip abductors and intensity of pain (r = - 0.70; p < 0.05) and VISA-p score (r = 0.63; p < 0.05) in the affected leg in athletes with unilateral PT.

CONCLUSIONS

Athletes with PT have decreased isometric strength in their hip abductors and external rotators when compared with controls. In subjects with unilateral PT, decreased isometric strength in the hip abductors is associated with greater intensity of pain and lower functional scores. Results of this study implied that hip muscle assessment and strengthening should be included for reconditioning and rehabilitation in athletes with PT.

Single-limb landing biomechanics are altered and patellar tendinopathy related pain is reduced with acute infrapatellar strap application

BACKGROUND

Patellar tendinopathy, a common condition of the knee, is often treated with patellar tendon straps to control pain during dynamic activity. Little is known regarding their effect on pain, landing kinematics and kinetics with their application. The purpose of this study was to determine if patellar tendon straps influenced pain, kinematics at landing and ground reaction forces in individuals with patellar tendinopathy versus healthy controls.

METHODS

Thirty participants with patellar tendinopathy and 30 controls participated. They completed single-limb landings with and without patellar tendon straps while pain, three-dimensional kinematics and vertical ground reaction forces were measured. A multivariate analysis of variance was completed to determine the differences in strapping condition and group for the dependent variables.

RESULTS

Individuals with patellar tendinopathy demonstrated a significant decrease in pain (no strap=37.1±22.1mm (mean±SD), strap=28.0±18.5mm (mean±SD)). With the strap at landing all participants displayed less hip rotation (F=7.16, p=.01), knee adduction (F=10.20, p=.002), ankle inversion (F=4.60, p=.04), and peak vertical ground reaction force (F=7.30, p=.009).

CONCLUSIONS

Patellar tendon straps reduced pain in those with patellar tendinopathy. Additionally, with the strap, individuals landed in a more neutral alignment and decreased landing forces which could provide a benefit to those with patellar tendinopathy.

Patellar tendon straps decrease pre-landing quadriceps activation in males with patellar tendinopathy

OBJECTIVE

To determine if patellar tendon straps altered quadriceps' muscle activity during a drop-jump landing in males with and without patellar tendinopathy.

DESIGN

Case-control.

SETTINGS

Biomechanics Research Laboratory.

PARTICIPANTS

Twenty recreationally-active males participated: ten (age = 21.3 ± 2.4 years, height = 182.8 ± 5.3 cm, mass = 81.7 ± 8.6 kg) with patellar tendinopathy; ten (age = 22.0 ± 1.6 years, height = 185.7 ± 4.5 cm, mass = 82.2 ± 9.8 kg) were healthy with no history of tendinopathy.

MAIN OUTCOME MEASURES

Electromyography (EMG) data for the vastus medialis (VM), rectus femoris (RF), and vastus lateralis (VL) muscles were collected. Five 2-legged 40 cm drop-jumps were performed wearing a patellar tendon strap and 5 with no-strap in a counterbalanced order. Root-mean square EMG (REMG) values of the VM, RF, and VL were averaged for a pre-landing and post-landing interval. Multiple mixed-model two-way ANOVAs were performed to determine the effect of tendinopathy and strapping condition on REMG values for each muscle.

RESULTS

For the pre-landing interval, all participants displayed lesser VL EMG activation (0.44 ± 0.19%, 0.53 ± 0.27%, respectively; p = 0.007, d = 0.39) in the no-strap compared with the strap condition.

CONCLUSIONS

When wearing a strap, all participants demonstrated lower VL activation prior to landing which may be helpful in reducing tensile stress at the tendon. These effects may be clinically important in modulating pain in those with patellar tendinopathy.