Ultrasound appearance of tendon tears. Part 2: lower extremity and myotendinous tears

Model of calf muscle tear during a simulated eccentric contraction, comparison between ex-vivo experiments and discrete element model

The tearing of the muscle-tendon complex (MTC) is one of the common sports-related injuries. A better understanding of the mechanisms of rupture and its location could help clinicians improve the way they manage the rehabilitation period of patients. A new numerical approach using the discrete element method (DEM) may be an appropriate approach, as it considers the architecture and the complex behavior of the MTC. The aims of this study were therefore: first, to model and investigate the mechanical elongation response of the MTC until rupture with muscular activation. Secondly, to compare results with experimental data, ex vivo tensile tests until rupture were done on human cadavers {triceps surae muscle + Achilles tendon}. Force/displacement curves and patterns of rupture were analyzed. A numerical model of the MTC was completed in DEM. In both numerical and experimental data, rupture appeared at the myotendinous junction (MTJ). Moreover, force/displacement curves and global rupture strain were in agreement between both studies. The order of magnitude of rupture force was close between numerical (858 N for passive rupture and 996 N-1032 N for rupture with muscular activation) and experimental tests (622 N ± 273 N) as for the displacement of the beginning of rupture (numerical: 28-29 mm, experimental: 31.9 mm ± 3.6 mm). These differences could be explained by choices of DEM model and mechanical properties of MTC's components or their rupture strain values. Here we show that he MTC was broken by fibers' delamination at the distal MTJ and by tendon disinsertion at the proximal MTJ in agreement with experimental data and literature.

Morphometric magnetic resonance imaging study of the quadriceps tendon in hemodialysis patients: comparison with non-dialyzed controls

Objective

To evaluate the knees of individuals with renal failure who are on hemodialysis, using magnetic resonance imaging (MRI), comparing them with those of a group of individuals with normal renal function.

Materials and Methods

This was a cross-sectional, observational, controlled study conducted between August 2018 and February 2020. The cases consisted of 15 patients who had been on hemodialysis for ≥ 5 years and did not have a quadriceps tendon rupture. The controls consisted of 15 individuals with normal renal function who were matched (1:1) to the cases for sex, age, and physical activity level. The subjects in both groups underwent MRI of the right knee only.

Results

The mean ages of the cases and controls were 50 ± 15 years and 49 ± 14 years, respectively. The median time on hemodialysis was 11 years (range, 10-14 years). Serum levels of parathyroid hormone, ferritin, alkaline phosphatase, phosphorus, and creatinine were higher among the cases than among the controls, whereas serum albumin and hemoglobin were lower (p < 0.05 for all). The MRI study showed a hyperintense signal in the quadriceps tendon in 11 of the cases and in three of the controls (p = 0.009). Knee joint effusion was observed in nine of the cases and in three of the controls (p < 0.05). The thickness, length, and width of the tendon did not differ between the groups. A hyperintense signal in the tendon was not associated with the time on hemodialysis; nor with the levels of intact parathyroid hormone, hemoglobin, or alkaline phosphatase.

Conclusion

Patients on chronic hemodialysis, even those without a tendon rupture, show a hyperintense signal in the quadriceps tendon on MRI.

Management of Anterior Tibialis Tendon Ruptures

Anterior tibialis tendon ruptures, while relatively infrequent ruptures, are commonly identified in delayed fashion, which can lead to significant impairments in patient gait and function. Surgical treatment is typically required to restore ankle dorsiflexion function and proper gait. Depending on various patient-specific factors, tendon quality and excursion, and chronicity, a range of treatment options are available to manage these patients, from nonsurgical care to surgical treatment. Surgical options include direct repair, local tendon transfer, autograft tendon reconstruction, and allograft tendon reconstruction. Additional procedures may need to be considered. Despite the variety of described surgical procedures, limited evidence-based guidelines are available to direct surgeons in the most optimal treatment for their patients. In addition to the relevant anatomy, biomechanics, and pathoanatomy, the reconstructive armamentarium is detailed and reviewed here, along with outcomes and potential complications, to guide surgeons in the most appropriate treatment for their patients.

Modeling of muscular activation of the muscle-tendon complex using discrete element method

The tearing of a muscle-tendon complex (MTC) is caused by an eccentric contraction; however, the structures involved and the mechanisms of rupture are not clearly identified. The passive mechanical behavior the MTC has already been modeled and validated with the discrete element method. The muscular activation is the next needed step. The aim of this study is to model the muscle fiber activation and the muscular activation of the MTC to validate their active mechanical behaviors. Each point of the force/length relationship of the MTC (using a parabolic law for the force/length relationship of muscle fibers) is obtained with two steps: 1) a passive tensile (or contractile) test until the desired elongation is reached and 2) fiber activation during a position holding that can be managed thanks to the Discrete Element model. The muscular activation is controlled by the activation of muscle fiber. The global force/length relationship of a single fiber and of the complete MTC during muscular activation is in agreement with literature. The influence of the external shape of the structure and the pennation angle are also investigated. Results show that the different constituents of the MTC (extracellular matrix, tendon), and the geometry, play an important role during the muscular activation and enable to decrease the maximal isometric force of the MTC. Moreover, the maximal isometric force decreases when the pennation angle increases. Further studies will combine muscular activation with a stretching of the MTC, until rupture, in order to numerically reproduce the tearing of the MTC.

Ultrasound Assessment of Muscle Injury Associated with Closed Limb Fracture

Objective

The aim of this study was to assess muscle injury associated with upper and lower closed limb fracture using ultrasound, and to develop ultrasound classification criteria for muscle injury.

Patients and Methods

Thirty patients with limb fracture and muscle injury participated in this study. Ultrasonography was used to assess muscle fibre, hematoma, vascular injury, and diameter growth rate. Injury was classified into three grades according to the ultrasound imaging: scores of less than, equal to, or greater than 9.

Results

Of 30 patients, focal fibre rupture was observed in 11 cases; in 9 cases, the injured area exceeded 30% of the muscle area. Six patients had muscle hematoma (the largest reaching 39 mm); in 4 patients, the hematoma showed a honeycombed pattern. Vascular rupture was observed in 6 patients, of which 2 had decreased main arterial diameter and blood flow. The greatest increase in muscle thickness was 17 mm. Of all patients, 11 showed an increase in the diameter growth rate of the muscle exceeding 50%. In addition, among the 30 patients, 11 patients with scores ranging from 4 to 8 received conservative treatment; 9 patients with scores ranging from 10 to 14 received operative treatment; and 10 patients with scores equal to 9 received either conservative or operative treatment.

Conclusions

Ultrasonography is useful for diagnosing muscle injury associated with closed limb fracture. The ultrasound classification criteria for muscle injury can be used to assess the severity of injury and guide the decision of treatment.

The painful total hip replacement: diagnosis and deliverance

Total hip replacement (THR) is a very common procedure undertaken in up to 285 000 Americans each year. Patient satisfaction with THR is very high, with improvements in general health, quality of life, and function while at the same time very cost effective. Although the majority of patients have a high degree of satisfaction with their THR, 27% experience some discomfort, and up to 6% experience severe chronic pain. Although it can be difficult to diagnose the cause of the pain in these patients, this clinical issue should be approached systematically and thoroughly. A detailed history and clinical examination can often provide the correct diagnosis and guide the appropriate selection of investigations, which will then serve to confirm the clinical diagnosis made.

Mechanisms of increased passive compliance of hamstring muscle-tendon units after spinal cord injury

BACKGROUND

People with spinal cord injury sometimes develop abnormally compliant hamstring muscle-tendon units. This study investigated whether the increased muscle-tendon compliance is due to a change in the passive properties of the muscle fascicles or tendons, or to muscle tears.

METHODS

Semimembranosus muscle fascicle lengths were measured from ultrasound images obtained from 15 spinal cord injured subjects and 20 control subjects while the hip was passively flexed with the knee extended. Semimembranosus muscles of spinal cord injured subjects were inspected for tears using ultrasound imaging.

FINDINGS

The mean (SD) hip angle at 30 Nm was 97 (SD 24) degrees in spinal cord injured subjects and 70 (SD 11) degrees in control subjects, indicating that spinal cord injured subjects had very compliant hamstring muscle-tendon units. The ratio of change in fascicle length to change in muscle-tendon length was not statistically different between spinal cord injured subjects and control subjects: muscle fascicles lengthened by 0.30 (SD 0.24) mm/mm in spinal cord injured subjects and 0.42 (SD 0.29) mm/mm in control subjects. These data were used to show that there was evidence of increased tendon compliance of spinal cord injured subjects compared to control subjects, but no evidence of increased muscle fascicle compliance. No tears were observed in semimembranosus muscles of spinal cord injured subjects.

INTERPRETATION

The increased hamstring muscle-tendon compliance apparent in some spinal cord injured subjects is due, at least in part, to increased tendon compliance. There was no evidence that the increased muscle-tendon compliance was due to muscle tears.

Detection of small tendon lesions by sonoelastographic visualization of strain profile differences: initial experiences

PURPOSE

To assess the capability of a commercial sonoelastography system to detect small tendon lesions by quantitative analysis of elastogram profiles.

MATERIALS AND METHODS

Strips of equine digital flexor tendons were used to model small human tendons. Two tendons were examined. From each tendon, six unmodified tendon strips (controls) and six tendon strips with a central defect of the same tendons were compared. The tendon strips were placed under a physiological tensile strain of 5%. Sonoelastographic visualization of the strain profile was performed. Regions of interest (ROI) were defined left and right of the tendon defects. Average tissue strains in these ROI were compared with tissue strain in controls.

RESULTS

In the first series of experiments, there was a significant (p = 0.011) difference in the strain profile in regions proximal and distal to the tendon lesions compared with the respective tendon areas in the control tendon strips. In a second series of experiments, similar trends were observed, but the differences were not significant (p = 0.824).

CONCLUSION

Even under carefully controlled experimental conditions using computational post-processing of sonoelastograms, tendon lesions could only be partially detected within elastograms from a clinical sonoelastography system. The ability to detect differences in some strain profiles indicates that tensile sonoelastography has the potential to identify small tendon lesions (such as those in the hand), but that substantial improvements with respect to quantitative analysis are required to make such measures diagnostically relevant.

Office-based ultrasound in sports medicine practice

Increasing knowledge, interest, and visibility in the field of sports medicine has equipped clinicians in the field with a novel array of diagnostic and therapeutic options but has also provided a higher level of complexity in patient care. True understanding of the vast spectrum of radiographic technology available to the sports clinician has become more critical than ever. Advances particularly in the areas of magnetic resonance imaging, diagnostic office ultrasound, and 3-dimensional reconstruction computed tomography, as well as nuclear medicine, offer the clinician a myriad of diagnostic options in patient evaluation. As these advances accumulate, the challenge to optimize care, contain cost, and interpret the extensive data generated becomes even more difficult to manage. Improving technology, education, and application of office ultrasound offers an interesting new tool for the bedside evaluation in real time of dynamic motion and pathology of sports-related injuries. As studies continue to validate ultrasound's effectiveness in diagnosing injuries to the upper and lower extremities compared with more costly magnetic resonance imaging and more invasive exploratory surgery, its promise as a cost-effective diagnostic tool is growing. A particularly promising development in the care of sports injuries is the expansion of injection therapies, and in-office ultrasound provides assurance that prolotherapy, platelet-rich plasma, dry needling, corticosteroid, and viscosupplementation are delivered accurately and safely. Communication with patients continues to increase in complexity because a greater understanding of the presence of radiographic abnormalities irrelevant to the current complaint is gained. All the accumulated data must then be interpreted and communicated to the patient with a firm understanding of not only the patient history and physical examination but also the availability, indications, contraindications, sensitivity, specificity, and even the cost implications of the spectrum of diagnostic options.

Imaging in sports medicine: an overview

Increasing sports participation, and the inevitable sports injury, is a significant contributor to total healthcare expenditure in the United States. With sports-related injury ever increasing, and technology rapidly expanding in the areas of diagnosis and treatment of musculoskeletal trauma, a continual revisiting of the latest in technology is critical for the sports physician. Advances particularly in the areas of magnetic resonance imaging, diagnostic office ultrasound, and 3-dimensional reconstruction computed tomography, offer the clinician a myriad of diagnostic options in patient evaluation. Care must be exercised, however, as one pursues additional radiographic data in the patient care arena. The information must be interpreted with a firm foundation and understanding of not only the patient history and physical examination, but also the availability, indications, contraindications, sensitivity, specificity, and even the cost implications of the great spectrum of diagnostic options.

Quadriceps tendinosis and patellar tendinosis in professional beach volleyball players: sonographic findings in correlation with clinical symptoms

The purpose was to assess quadriceps and patellar tendinosis in professional beach volleyball players and to correlate ultrasound findings with clinical symptoms. During a grand-slam beach volleyball tournaments all 202 athletes (100 men and 102 women) were invited to participate at this study. Sixty-one athletes (38 male, mean age 29.6, 23 female, mean age 27.1) were included. The dominant leg was right in 51 (84%) and left in ten athletes (16%). Lysholm knee score and pain during the game was assessed using a visual analogue scale. Sonography of the quadriceps tendon and the patellar tendon was performed by a blinded sonographer. Sonographic findings were compared between both legs and correlated to clinical findings using a regression analysis. Quadriceps tendinosis was diagnosed in 13 (21%, dominant leg)/21 (34%, non-dominant leg), patellar tendinosis in 13(21%)/18(30%). Only sonographic findings at the quadriceps tendon were significantly associated with pain: thickness of the quadriceps tendon (mean diameter 6.9 mm/7.1 mm, significant for both legs P = 0.011/P = 0.030), abnormal echo texture (11/16; P = 0.001/P = 0.228), areas with positive power Doppler signals (mean number 0.3/0.4; P = 0.049/0.346), calcifications (mean number: 0.9/1.1; P = 0.021/0.864). A relationship between findings at patellar tendon was not found. Quadriceps tendinosis is as common as patellar tendinosis in professional beach volleyball players. Thickening and structure alteration of the quadriceps tendon is associated with anterior knee pain during beach volleyball.