Shear wave elastography of the healing human patellar tendon following ACL reconstruction

Regional Patellar Tendon Strain in the Short- and Long-term After ACL Reconstruction Using Bone-Patellar Tendon-Bone Autograft

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) often involves harvesting a bone-patellar tendon-bone (BPTB) autograft. How graft harvest affects tendon strain across the 3 distinct regions (medial, lateral, and central) is not known.

PURPOSE

To (1) quantify strain in the 3 regions of the patellar tendon during 60% of maximum voluntary isometric contraction (MVIC) in 90° of knee flexion and (2) assess how effort level in 2 different knee joint angles (60° and 90°) impacts strain in the medial and lateral regions of the patellar tendon, in 2 cohorts of patients after ACLR using a BPTB autograft (one group <24 months after surgery and another group ≥24 months after surgery).

STUDY DESIGN

Descriptive laboratory study.

METHODS

Effort levels ranging from 20% to 100% of MVIC were performed at 90° and 60° of knee flexion on an isokinetic dynamometer, with simultaneous ultrasound imaging of tendon length to calculate regional strain. Linear mixed-effects models were used to evaluate regional strain at 60% of MVIC in 90° of knee flexion. The fixed effects of percentage of MVIC, joint angles, and time from surgery groups on patellar tendon strain were evaluated using separate models for the medial and lateral regions.

RESULTS

Fourteen participants in the short-term group (7.5 ± 1.9 months from surgery) and 15 participants in the long-term group (71.5 ± 16.5 months from surgery) were included. At 60% of MVIC in 90° of knee flexion, the short-term group demonstrated lower patellar tendon strain than the long-term group regardless of region (P < .01). The central region also had lower strain than the medial and lateral regions regardless of group (both P < .01). Finally, the rate at which strain increased with increasing effect levels differed between time from surgery groups in both medial and lateral regions.

CONCLUSION

The short-term group had lower strain in all regions of the patellar tendon after ACLR using BPTB autograft. The medial and lateral regions showed varying strain based on time from surgery and effort level. Varying knee joint angles and effort levels for graft site rehabilitation may have to be considered to target specific regions of the patellar tendon.

CLINICAL RELEVANCE

Clinicians should consider the time elapsed since surgery and the manipulation of knee angle as factors that can exert varying levels of strain on different regions of the patellar tendon after ACLR. Accelerating quadriceps strengthening to enhance strain distribution across the patellar tendon to promote tendon healing may be of benefit for optimizing postsurgery rehabilitation.

Shear-wave elastography of canine patellar tendons in healthy dogs and the influence of stifle joint angle

Elastography is a sonographic modality that measures tissue stiffness, a mechanical property of tissues, and a biomarker for disease. Canine musculoskeletal application to the patellar tendon has been limited to semiqualitative strain elastography. This prospective study aimed to quantitatively evaluate patellar tendon stiffness using shear-wave elastography with a color map superimposed over the tendon, a propagation map for quality control, and measurements at specific regions of interest in 16 clinically normal sedated dogs weighing 25 kg or greater. Tendon stiffness using shear-wave elastography (SWE) was assessed at different stifle angles and in three regions to determine if angle and location affected stiffness. All dogs were screened with general and orthopedic exams, lateral stifle radiographs, and patellar tendon 2D ultrasound. Shear-wave elastography was performed from a long axis at various stifle angles at the proximal, middle, and distal tendon segments. Quality diagnostic SWE results varied significantly with stifle angle, and 150° of extension was the only angle found to be clinically useful based on the ease of obtaining measurable results and a quality control propagation wave. Patellar tendons were primarily stiff with a red color elastogram. The proximal and middle segments, measured at various angles, had a mean SWE velocity of 7.32 ± 0.90 m/s. Tendon stiffness did not differ along tendon length when measured in greater extension. However, stiffness decreased in the middle segment of the tendon at 150° when compared with 120°. This study establishes a quantitative baseline of normal patellar tendon stiffness to compare with pathologic states.

Comparison of early outcomes of primary total knee arthroplasties performed using subvastus and medial parapatellar approaches and evaluation of quadriceps muscle elastography

BACKGROUND

In primary total knee arthroplasty (TKA) surgeries, the medial parapatellar (MP) and subvastus (SV) approaches are frequently employed. The SV approach involves preserving the vastus medialis muscle, leading to debates about the possibility of earlier healing of the extensor mechanism. Shear wave elastography (SWE) is known for monitoring tissue healing. In this study, our research question revolves around whether there exist differences in tissue healing following MP and SV approaches. Unlike previous studies, we aim to investigate this difference using solely SWE, which provides a quantitative measurement specifically targeting the vastus medialis muscle.

METHODS

We divided 17 patients into two groups: SV (10 patients) and MP (7 patients). SWE measurements and clinical scores were recorded before surgery and at the 3rd-month follow-up. The first straight leg raising days were also recorded.

RESULTS

Both the MP and SV groups showed significant improvement in clinical scores postoperatively. Straight leg raising time was comparatively earlier in the SV group, but no significant difference was found. SWE measurements revealed similar recovery values in the vastus medialis muscle between the two groups.

CONCLUSION

Both MP and SV approaches demonstrate similar and favorable early outcomes in TKA surgery. The preservation of the vastus medialis in the SV approach does not lead to significant differences in clinical scores or muscle recovery compared to the MP approach.

TRIAL REGISTRATION

The study was retrospectively registered on ClinicalTrials.gov on March 7, 2024 (NCT06297746). https://classic.

CLINICALTRIALS

gov/ct2/show/NCT06297746?id=am7mi3VB&draw=2&rank=1 .

Effects of clamshell exercises in terminal extension lag after ACL reconstruction

BACKGROUND

Terminal extension lag (TEL) is common following anterior cruciate ligament reconstruction (ACLR). Clamshell exercises have been suggested as a potential intervention to address TEL, but limited research has been conducted in this area.

OBJECTIVE

This study aimed to determine the effects of Clamshell exercises in terminal extension lag after anterior cruciate ligament reconstruction.

METHODS

This randomized controlled trial included 40 participants with a history of ACLR between 1 and 3 years prior. Participants were randomly assigned to either the experimental group (Group A) or the control group (Group B). Group A received conventional exercises along with isolated hip strengthening rehabilitation, while Group B received conventional exercises without specific hip strengthening. The primary outcomes were pain levels (Numeric Pain Rating Scale), knee function (International Knee Documentation Committee scores, (IKDC)), range of motions (goniometer) and strength (sphygmomanometer).

RESULTS

In between the group comparison shows that all outcome measures (NPRS, IKDC, Goniometer, Sphygmomanometer) show significant results (p < 0.05). Within-group comparisons (paired sample t-test) show that there was a significant difference (p < 0.05) in all outcome measures of both groups.

CONCLUSION

The addition of Clamshell exercises to the rehabilitation program resulted in a significantly greater reduction in TEL compared to the control group. These findings suggest that Clamshell exercises were found to be an effective intervention for addressing TEL after ACLR.

Time to treat the tendon rupture induced by surgery: early hypertrophy of the patellar tendon graft site predicts strong quadriceps after ACLR with bone-patellar tendon-bone autograft

PURPOSE

Quadriceps dysfunction is ubiquitous after anterior cruciate ligament reconstruction, especially when using bone-patellar tendon-bone (BPTB) autografts. The role of patellar tendon hypertrophy after graft harvest on knee extensor strength is unknown. The purpose of this study was to determine the predictive ability of patellar tendon (PT) and quadriceps muscle (Quad) cross-sectional area (CSA) on knee extensor strength 1-2 months after ACLR using BPTB autografts.

METHODS

This is a cross-sectional analysis of a cohort 1-2 months after ACLR using BPTB autograft. Peak knee extensor torque, and PT and Quad CSA measured using ultrasound imaging, were collected in 13 males and 14 females. Simple linear regressions compared quadriceps strength index (QI) against limb symmetry index (LSI) in PT and Quad CSA. Multiple linear regressions with sequential model comparisons predicting peak knee extensor torque were performed for each limb. The base model included demographics. Quad CSA was added in the first model, then PT CSA was added in the second model.

RESULTS

Both PT (p < 0.001, R2 = 0.693) and Quadriceps CSA (p = 0.013, R2 = 0.223) LSI had a positive linear relationship with QI. In the involved limb, addition of PT CSA significantly improved the model (R2 = 0.781, ΔR2 = 0.211, p for ΔR2 < 0.001). In the uninvolved limb, the addition of Quad CSA improved the model, but the addition of PT CSA did not.

CONCLUSION

PT LSI was more predictive of QI than Quad CSA LSI. Involved limb PT CSA mattered more in predicting peak knee extensor torque than did Quad CSA, but in the uninvolved limb, Quad CSA was the most important predictor of peak knee extensor torque. Graft site patellar tendon hypertrophy is key for strong quadriceps early after ACLR. Early targeted loading via exercise to promote healing of the graft site patellar tendon may bring patients a step closer to winning their battle against quadriceps dysfunction.

LEVEL OF EVIDENCE

Level I.

Evaluation of the knee joint with ultrasound and magnetic resonance imaging

The knee joint relies on a combination of deep and superficial structures for stability and function. Both ultrasound and high-resolution magnetic resonance imaging are extremely useful in evaluating these structures and associated pathology. This article reviews a combination of critical anatomic structures, joint abnormalities, and pathologic conditions at the knee joint, while highlighting the merits, limitations, and pitfalls of the two imaging modalities. A clear appreciation of each method paired with its relative strengths will aid in expediting diagnosis and appropriate treatment for a wide range of knee joint conditions.

Emerging Role of Quantitative Ultrasound-Based Imaging Techniques for Characterizing Rotator Cuff Tears: A Scoping Review

Rotator cuff myosteatosis following cuff tears is very common and one of the most important prognostic factors in clinical management. Quantitative ultrasound-based imaging techniques (QUBIT) are frequently used along with magnetic resonance imaging (MRI) to evaluate rotator cuff fatty degeneration. However, the examination of rotator cuff tissue integrity by QUBIT is lacking a standardized imaging protocol and procedural methodologies. In this scoping review, we synthesized the current state of QUBIT against the reference imaging modalities in patients with rotator cuff tears. The literature search was extracted from 963 studies, with 22 studies included in the final review in accordance with the preferred reporting items for systematic reviews and meta-analyses extensions for scoping reviews. The selected studies included human participants and focused on measuring at least one prognostic or diagnostic factor using ultrasonography-based imaging with reference to MRI. The findings suggest both conventional B-mode ultrasound and shear wave elastography imaging were comparable to MRI-based imaging techniques for the evaluation of fatty infiltration and rotator cuff tear characterization. This review establishes guidelines for reporting shoulder-specific QUBIT aimed at developing a standardized imaging protocol. The objective was to enhance the diagnostic and prognostic capabilities of QUBIT in the clinical setting.

Dynamic knee joint stiffness during bilateral lower extremity landing 6 months after ACL reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) reconstructions are associated with long-term functional impairments. Improved understanding of dynamic knee joint stiffness and work may provide insights to help address these poor outcomes. Defining the relationship between knee stiffness, work and quadriceps muscle symmetry may reveal therapeutic targets. The purposes of this study were to investigate between-limb differences in knee stiffness and work during early phase landing 6-months after an ACL reconstruction. Additionally, we investigated relationships among symmetry of knee joint stiffness and work during early-phase landing and quadriceps muscle performance symmetry.

METHODS

Twenty-nine participants (17 M, 20.0 ± 5.3 years) were tested 6-months after ACL reconstruction. Motion capture analysis was used to assess between-limb differences in knee stiffness and work during the first 60 ms of a double-limb landing. Quadriceps peak strength and rate of torque development (RTD) were assessed with isometric dynamometry. Paired t-tests and Pearson's product moment correlations were used to determine between-limb differences of knee mechanics and correlations of symmetry respectively.

FINDINGS

Knee joint stiffness and work were significantly reduced (p < 0.01, p < 0.01) in the surgical limb (0.021 ± 0.01 Nm*(deg*kg*m)-1, -0.085 ± 0.06 J*(kg*m) -1) compared to the uninvolved limb (0.045 ± 0.01 Nm*(deg*kg*m)-1, -0.256 ± 0.10 J*(kg*m) -1). Greater knee stiffness (51 ± 22%) and work (35 ± 21%) symmetry were significantly associated with greater RTD symmetry (44.5 ± 19.4%) (r = 0.43, p = 0.02; r = 0.45, p = 0.01) but not peak torque symmetry (62.9 ± 16.1%) (r = 0.32, p = 0.10; r = 0.34, p = 0.10).

INTERPRETATION

Dynamic stiffness and energy absorption are lower in the surgical knee during landing from a jump. Therapeutic interventions that target increasing quadriceps RTD may help optimize dynamic stability and energy absorption during landing.

Reliability of Continuous Shear Wave Elastography in the Pathological Patellar Tendon

OBJECTIVES

Patellar tendon injuries occur via various mechanisms such as overuse, or due to surgical graft harvest for anterior cruciate ligament reconstruction (ACLR). Quantified patellar tendon stiffness after injury may help guide clinical care. Continuous shear wave elastography (cSWE) allows for the assessment of viscosity and shear modulus in tendons. The reliability of the measure, however, has not been established in the patellar tendon. The purpose of this study was to investigate the interrater reliability, intrarater reliability, and between-day stability of cSWE in both healthy and pathological patellar tendons.

METHODS

Participants with patellar tendinopathy (n = 13), history of ACLR using bone-patellar tendon-bone autograft (n = 9), and with no history of patellar tendon injury (n = 13) were recruited. cSWE was performed 4 times by multiple raters over 2 days. Intraclass correlations (ICC) and minimum detectable change (MDC_95% ) were calculated.

RESULTS

Good to excellent between-day stability were found for viscosity (ICC = 0.905, MDC_95%  = 8.3 Pa seconds) and shear modulus (ICC = 0.805, MDC_95%  = 27.4 kPa). The interrater reliability measures, however, were not as reliable (ICC = 0.591 and 0.532).

CONCLUSIONS

cSWE is a reliable assessment tool for quantifying patellar tendon viscoelastic properties over time. It is recommended, however, that a single rater performs the measure as the interrater reliability was less than ideal.

Bone-Patellar Tendon-Bone Autograft Harvest Prolongs Extensor Latency during Gait 2 yr after ACLR

PURPOSE

Bone-patellar tendon-bone (BPTB) graft harvest for anterior cruciate ligament reconstruction alters patellar tendon properties, which inflict poor quadriceps neuromuscular function. BPTB autografts are associated with higher rates of posttraumatic osteoarthritis, which in turn is associated with pathological gait. The purpose of this study was to investigate the latency between the time of peak quadriceps activity and the peak knee flexion moment during gait, between those with BPTB grafts ( n = 23) and other graft types (hamstring autograft or allografts, n = 54), 5 ± 2 months and 2 yr (25 ± 3 months) after anterior cruciate ligament reconstruction. We hypothesized that longer latencies would be observed in the BPTB graft group in the involved limb. We expected latencies to shorten over time.

METHODS

Knee moments and quadriceps EMG were collected during gait, and vastus medialis, vastus lateralis, rectus femoris (RF), and quadriceps latencies were calculated. Linear mixed-effects models were used to compare latencies between graft types and over the two time points.

RESULTS

The main effects of graft type were observed for vastus medialis ( P = 0.005) and quadriceps ( P = 0.033) latencies with the BPTB graft group demonstrating longer latencies. No main effects of graft type were observed for vastus lateralis ( P = 0.051) and RF ( P = 0.080) latencies. Main effects of time were observed for RF latency ( P = 0.022).

CONCLUSIONS

Our hypothesis that the BPTB graft group would demonstrate longer extensor latency was supported. Contrary to our second hypothesis, however, latency only improved in RF and regardless of graft type, indicating that neuromuscular deficits associated with BPTB grafts may persist 2 yr after surgery. Persistent deficits may be mediated by changes in the patellar tendon's mechanical properties. Graft-specific rehabilitation may be warranted to address the long-term neuromechanical deficits that are present after BPTB graft harvest.

Advances in non-invasive biosensing measures to monitor wound healing progression

Impaired wound healing is a significant financial and medical burden. The synthesis and deposition of extracellular matrix (ECM) in a new wound is a dynamic process that is constantly changing and adapting to the biochemical and biomechanical signaling from the extracellular microenvironments of the wound. This drives either a regenerative or fibrotic and scar-forming healing outcome. Disruptions in ECM deposition, structure, and composition lead to impaired healing in diseased states, such as in diabetes. Valid measures of the principal determinants of successful ECM deposition and wound healing include lack of bacterial contamination, good tissue perfusion, and reduced mechanical injury and strain. These measures are used by wound-care providers to intervene upon the healing wound to steer healing toward a more functional phenotype with improved structural integrity and healing outcomes and to prevent adverse wound developments. In this review, we discuss bioengineering advances in 1) non-invasive detection of biologic and physiologic factors of the healing wound, 2) visualizing and modeling the ECM, and 3) computational tools that efficiently evaluate the complex data acquired from the wounds based on basic science, preclinical, translational and clinical studies, that would allow us to prognosticate healing outcomes and intervene effectively. We focus on bioelectronics and biologic interfaces of the sensors and actuators for real time biosensing and actuation of the tissues. We also discuss high-resolution, advanced imaging techniques, which go beyond traditional confocal and fluorescence microscopy to visualize microscopic details of the composition of the wound matrix, linearity of collagen, and live tracking of components within the wound microenvironment. Computational modeling of the wound matrix, including partial differential equation datasets as well as machine learning models that can serve as powerful tools for physicians to guide their decision-making process are discussed.

The comparison of the effectiveness of Kinesio Taping and dry needling in the treatment of lateral epicondylitis: a clinical and ultrasonographic study

BACKGROUND

The aim of this study was to investigate the short- and long-term effects of Kinesio Taping (KT) and dry needling (DN) applications on pain, functionality, and muscle strength in patients with lateral epicondylitis by use of questionnaires and ultrasonography.

METHODS

Seventy-eight patients were randomized into 3 groups. Each group followed a program that consisted of 9 treatment sessions in total, with 3 sessions per week for 3 weeks. Group 1 received KT and performed exercise, group 2 received DN and performed exercise, and group 3 performed exercise alone. Pain, functional status, grip strength, and the thickness and echogenicity of the common extensor tendon were evaluated before treatment, after treatment (at the end of the third week), and after 6 months.

RESULTS

In intragroup evaluations, KT and DN were found to be effective in the short and long term in terms of pain, functional status, muscle strength, and tendon thickness (P < .01). In intergroup evaluations, improvement in the KT and DN groups was superior to that in the control group for all parameters (P < .05). On comparison of the KT and DN groups, improvements in the clinical parameters and tendon thickness, heterogeneity, and elastography were significantly better in the DN group in the short and long term (P < .05).

CONCLUSIONS

The ultrasonographic outcomes in our study objectively demonstrated that although DN in general is superior in the treatment of lateral epicondylitis, KT treatment is also effective.

Influence of Bias in the Assessment of Patellar Tendon Stiffness: A Systematic Review and Meta-analysis

The aim of the present study was to provide a systematic review and meta-analysis of the main biases in practical applications of the different types of elastography in assessment of the stiffness of healthy patellar tendons. A literature search on four databases (Scopus, Web of Science, Pubmed and SportDiscus) was conducted on March 25, 2020. After analysis of 1,052 resultant articles, studies were included if they met two inclusion criteria: (1) studies were observational or randomized controlled trials; (2) studies included outcomes of patellar tendon stiffness. Twenty-one studies met the inclusion criteria and were included in this meta-analysis. Four meta-analyses were performed with respect to assessment procedure and participant characteristics. This meta-analysis found a low effect of examined portion of patellar tendon (standardized mean difference [SMD] = 0.27, 95% confidence interval [CI]: 0.01-0.54, n = 379, Z = 2.01, p = 0.04) and a high effect of knee flexion angle during assessment (SMD = -2.12; 95% CI: -2.67 to -1.58, n = 97, Z = 7.68, p < 0.01) in stiffness outcomes. The risk of bias was generally low, but the heterogenicity of the results downgraded the level of evidence. There is evidence in the elastography assessment of patellar tendon suggesting that the knee position and patellar tendon portion evaluated influence stiffness outcomes for patellar tendon in healthy volunteers.

Three-Dimensional Mapping of Shear Wave Velocity in Human Tendon: A Proof of Concept Study

Ultrasound-based shear wave elastography (SWE) provides the means to quantify tissue mechanical properties in vivo and has proven valuable in detecting degenerative processes in tendons. Its current mode of use is for two-dimensional rendering measurements, which are highly position-dependent. We therefore propose an approach to create a volumetric reconstruction of the mechano-acoustic properties of a structure of interest based on optically tracking the ultrasound probe during free-hand measurement sweeps. In the current work, we aimed (1) to assess the technical feasibility of the three-dimensional mapping of unidirectional shear wave velocity (SWV), (2) to evaluate the possible artefacts associated with hand-held image acquisition, (3) to investigate the reproducibility of the proposed technique, and (4) to study the potential of this method in detecting local adaptations in a longitudinal study setting. Operative and technical feasibility as well as potential artefacts associated with hand-held image acquisition were studied on a synthetic phantom containing discrete targets of known mechanical properties. Measurement reproducibility was assessed based on inter-day and inter-reader scans of the patellar, Achilles, and supraspinatus tendon of ten healthy volunteers and was compared to traditional two-dimensional image acquisition. The potential of this method in detecting local adaptations was studied by testing the effect of short-term voluntary isometric loading history on SWV along the tendon long axis. The suggested approach was technically feasible and reproducible, with a moderate to very good reliability and a standard error of measurement in the range of 0.300-0.591 m/s for the three assessed tendons at the two test-retest modalities. We found a consistent variation in SWV along the longitudinal axis of each tendon, and isometric loading resulted in regional increases in SWV in the patellar and Achilles tendons. The proposed method outperforms traditional two-dimensional measurement with regards to reproducibility and may prove valuable in the objective assessment of pathological tendon changes.

Evaluation of patellar tendon with shear wave elastography after anterior cruciate ligament reconstruction using hamstring tendons

Objectives

This study aims to evaluate the characteristics of patellar tendons (PTs) of patients who underwent anterior cruciate ligament reconstruction (ACLR) with hamstring tendon autograft using shear wave elastography (SWE).

Patients and methods

This prospective study was conducted between August 2017 and February 2018. We performed brightness mode (B-mode) ultrasound and SWE on 21 patients (20 males, 1 female; mean age 32 years; range, 19 to 42 years) who underwent ACLR with a single-bundle transtibial technique using quadruple hamstring autografts and 14 healthy controls (13 males, 1 female; mean age 35 years; range, 25 to 47 years). Length and thickness of the PT were evaluated with B-mode ultrasound, while elasticity values were evaluated with SWE in the patient and control groups.

Results

The mean SWE value of the patient group on the operated side was 25.30 (min-max=16.60-46.20) and on the non-operated side 23.20 (min-max=12.40-44). There were no statistically significant differences regarding PT elasticity, thickness, or length between the groups (p>0.05).

Conclusion

There were no differences regarding elasticity, length, or thickness between the operated and healthy knees detected with SWE. Upcoming research should focus on tendon biopsy and biochemical analyses for the identification of possible intrastructural changes of the tendon due to collagen synthesis after ACLR with hamstring autograft.

Assessment of common extensor tendon elasticity in patients with lateral epicondylitis using shear wave elastography

Background

To investigate the role of shear wave elastography (SWE) in patients with lateral epicondylitis (LE) by assessing the common extensor tendon (CET) elasticity.

Methods

A total of 62 unilateral LE patients were enrolled. Shear wave speed (SWS) and the thickness of CET in both elbows, along with the involved elbows with pre- and post-treatment, were obtained by SWE. The differences between groups, inter- and intra-observer agreements, and diagnostic accuracy were analyzed with a paired t-test, intraclass correlation coefficients (ICCs), and receiver operator characteristic (ROC) curve, respectively.

Results

LE patients had significantly lower SWS on lesion sides compared to healthy elbows (P<0.05). The SWS of involved elbows were significantly higher after non-operation treatment than before treatment. The inter- and intra-observer agreements were excellent (ICCs: 0.900-0.993) for SWE measurements. Moreover, a 12.2 m/s cutoff value of mean SWS (C _mean) for discriminating LE patients from healthy subjects revealed a sensitivity and specificity of 93% and 93%, respectively.

Conclusions

SWE is a valid imaging technique for the diagnosis of LE and monitoring of the treatment effect. Future studies are essential for investigating the correlations among clinical examinations, conventional ultrasound, and SWE.