Distal Tendon Research Articles

What Is the Relationship Between the Distal Semimembranosus Tendon and the Medial Meniscus? A Gross and Microscopic Analysis From the SANTI Study Group

Background: Some authors have suggested that the semimembranosus tendon is involved in the pathophysiology of ramp lesions. This led us to conduct a gross and microscopic analysis of the posterior horn of the medial meniscus and the structures inserted on it. Hypothesis: (1) The semimembranosus tendon has a tendinous branch inserting into the posterior horn of the medial meniscus, and (2) the meniscotibial ligament is inserted on the posteroinferior edge of the medial meniscus. Study Design: Descriptive laboratory study. Methods: In total, 14 fresh cadaveric knees were dissected. From each cadaveric donor, a stable anatomic specimen was harvested en bloc, including the medial femoral condyle, medial tibial plateau, whole medial meniscus, cruciate ligaments, joint capsule, and distal insertion of the semimembranosus tendon. The harvested blocks were cut along the sagittal plane to isolate the distal insertion of the semimembranosus tendon on the posterior joint capsule and the posterior horn of the medial meniscus in a single slice. Histological slides were made from these samples and analyzed under a microscope. Results: In all knees, gross examination revealed a direct branch of the semimembranosus and a tendinous capsular branch ending behind the posterior horn of the medial meniscus. This capsular branch protruded over the joint capsule, over the meniscotibial ligament below and the meniscocapsular ligament above, but never ended directly in the meniscal tissue. The capsular branch was 14.3 ± 4.4 mm long (mean ± SD). The direct tendon inserted 11 ± 2.8 mm below the articular surface of the tibial plateau. The meniscotibial ligament inserted on the posteroinferior edge of the medial meniscus, and the meniscocapsular ligament insertion was on its posterosuperior edge. Highly vascularized adipose tissue was found, delimited by the posterior horn of the medial meniscus, meniscotibial ligament, meniscocapsular ligament, and capsular branch of the semimembranosus tendon. Conclusion: In all knees, our study found a capsular branch of the semimembranosus tendon inserted behind the medial meniscus. The meniscotibial ligament was inserted on the posteroinferior edge of the medial meniscus. Histological analysis of this area revealed that this ligament inserted differently from the insertion previously described in the literature. Clinical Relevance: This laboratory study provides insight into the pathophysiology of ramp lesions frequently associated with anterior cruciate ligament injury. To restore anatomy, it is mandatory to reestablish meniscotibial ligament continuity in ramp repairs.

REINSERTION OF THE DISTAL TENDON OF A BICEPS USING ENDOBUTTON FROM A SINGLE INCISION TECHNIQUE

Summary. Surgical treatment of biceps distal tendon ruptures shows better functional results, compared to a conservative treatment. Recently, the one-incision surgical technique is becoming more and more popular. Task of the study: representation of a technique to recover a distal biceps tendon with a single incision and fixation with an Endobutton. Materials and methods: the single-incision technique for a distal biceps tendon recovery comprises of several steps: an incision place and layer-wise access, preparation of the distal biceps tendon, preparation of the radial tuberosity, fixation of the tendon. Results. The knowledge of anatomy and the correct sequence of steps in the single-incision technique with the fixation of a tendon with Endobutton (by ChM) makes the recovery of distal biceps tendon efficient, reliable, and, what is more important, safe.

Influence of body mass index and weight lifting on bicep brachii muscle and distal bicep tendon stiffness evaluated using ultrasound elastography

BackgroundThis study aimed to investigate the relationship between stiffness of the bicep brachii muscle (BBM) and distal bicep tendon (DBT) and effects of weight lifting (pre- to post-workout changes) among groups with different body mass indexes (BMI).MethodsParticipants were divided into four groups according to BMI: A, underweight (< 18.5 kg/m2); B, normal (18.5–24.9 kg/m2); C, overweight (25.0–29.9 kg/m2); and D, obese (> 30.0 kg/m2). All participants were males who were untrained and had sedentary lifestyle without involvement in sports activities for the past 12 months. Ultrasonographic measurements to determine muscle and tendon stiffness was performed on the dominant side (i.e., right side) of the upper extremities in all participants.ResultsTwenty-one healthy and untrained males volunteered to participate in this study; 14 were nonsmokers and 7 were smokers. The mean age and BMI were 22.5 ± 1.5 years and 23.8 ± 6.3 kg/m2, respectively. Groups A, B, C, and D had four, ten, four, and three participants, respectively. The BBM thickness did not increase with increase in BMI and was not significantly different (P > .05) between groups. The BBM stiffness was significantly different (all P < .05) from pre- to post-workout values in all groups, whereas DBT stiffness did not follow the same trend.ConclusionsOur study revealed that the BBM thickness is independent of BMI. After weight lifting, BBM stiffness in groups A and B increased for BBM compared to those in groups C and D. A similar trend was also recorded for DBT. Weight lifting in concentric and eccentric motions affects the stiffness of the BBM and DBT, thus weight lifting plays a role in adjusting the stiffness of the BBM and DBT.Trial registration The study was approved by ethics committee of the College of Applied Medical Sciences (CAMS 080-3839; March 14, 2018).

MRI findings of chronic distal tendon biceps reconstruction and associated post-operative findings.

Rupture of the distal biceps tendon is becoming increasingly diagnosed due to an active aging population and an increase in diagnostic imaging opportunities. While physical exam may help in diagnosis, magnetic resonance imaging (MRI) is particularly useful in evaluating chronic rupture. Although partial tears can be managed conservatively, the gold standard treatment for a chronic distal biceps tear is anatomic reinsertion with additional use of an allograft or autograft. No study has highlighted the normal appearance and postsurgical complications seen on MRI associated with allograft or autograft usage. Clinicians and radiologists may be unaware of the normal and abnormal post-operative imaging findings and their clinical relevance. The purpose of this manuscript is to discuss the epidemiology, clinical presentation, and preoperative MRI findings of distal biceps ruptures necessitating reconstruction, to explain distal biceps tendon surgical reconstruction technique with allograft or autograft usage, to display the normal and abnormal post-operative MRI findings, and to review the clinical outcomes associated with the procedure.

Successful reconstruction of distal peroneus longus tendon dislocation associated with a split lesion \u2013 a case report

BackgroundPeroneal tendon injuries are one of the differential diagnoses in lateral ankle and rearfoot pain. While partial tears are not uncommon, peroneal tendon dislocation at the peroneal tubercle is very rare. Until now, only three papers have been published, presenting five cases of peroneus longus tendon dislocation over the peroneal tubercle. This report adds a previously undescribed case of a peroneus longus tendon split tear that was partially dislocated and entrapped over the peroneal tubercle. The respective operative approach and the outcome are described.Case presentationA 25-year-old international top-level speed skater developed a painful mass over the lateral calcaneal wall. There was no specific inducing injury in his medical history. In contrast to previous reports, according to the patient’s history, a snapping phenomenon was not present. Conservative treatment was not effective. By inspection and palpation an enlarged peroneal tubercle was assumed. During operative exploration, we found an incomplete longitudinal split tear of the peroneus longus tendon, which was partially dislocated and entrapped over the peroneal tubercle. This mimicked an enlarged peroneal tubercle. A portion of the split tendon was resected. A deepening procedure of the flat groove of the peroneus longus tendon below the peroneal tubercle and a transosseous reconstruction of the avulsed inferior peroneal retinaculum were performed. After six months, the patient had completely reintegrated into his elite sport and has been free of symptoms since then.ConclusionsFrom the presented case it can be speculated that the inferior peroneal retinaculum was overused, worn out, detached, or ruptured due to overpronation and friction the lateral edge of the low-cut speed skating shoe. Then the peroneus longus tendon experienced substantial friction with the peroneal tubercle with possible dislocation during ankle motion. This frictional contact may have finally led to further degeneration and a longitudinal tear of the tendon. Obviously, dislocations can develop insidiously resulting in lesions of the peroneus longus tendon at the peroneal tubercle, ultimately leading to a tendon entrapment. This mimics an enlarged tubercle. The pathology is very rare and can be successfully addressed surgically.

Patellar Clunk Syndrome Following Posterior Stabilized Total Knee Replacement: Report of Two Cases

Patellar clunk syndrome (PCS) occasionally occurs after posterior stabilized total knee replacement (PS-TKR), and is characterized by a painful palpable audible clunk of the patella when the knee moves from flexion to extension. It has been classically attributed to the formation of fibrous nodule at the junction of the proximal pole of the patella and the undersurface of the distal quadriceps tendon. However, various intra-articular peripatellar proliferative fibrous formations have also been reported with a wide spectrum of symptoms, ranging from crepitation to frank patellar clunk. Treatment of the syndrome remains essentially surgical, and usually consists of resection of the fibrous nodules. This paper reports two cases of PCS and aims at bringing attention to this entity in terms of pathogenesis, clinical diagnosis, and treatment, through a review of the literature.

Morphological variability of the extensor hallucis longus in human fetuses

IntroductionThe extensor hallucis longus originates from about the middle three fifths of the anterior surface of the fibula, medial to the origin of the extensor digitorum longus, and inserts into the distal phalanx of the great toe. The goal of this study was to examine the insertion of the extensor hallucis longus tendon and thus prepare its first classification in human fetuses. Material and MethodsFifty spontaneously-aborted human fetuses (26 male, 24 female, 100 lower limbs), aged 18–38 weeks of gestation, were examined. ResultsThe classification comprised three types of extensor hallucis longus insertion. The most common was type I (68%), which was characterized by a single tendon that ends as an extensor hood inserting into the dorsal aspect of the base of the distal phalanx of the great toe. The second most frequent was type II (27%), which was characterized by two distal tendons: the dominant one ends as an extensor hood inserting into the distal phalanx of the great toe, and the auxiliary inserts separately into the dorsal aspect of the proximal phalanx of the great toe, medial to the insertion of the extensor hallucis brevis tendon. Finally, type III (5%), the least frequent type, was characterized by two distal tendons: the dominant one ends as an extensor hood inserting into the distal phalanx of the great toe, and the auxiliary connects to the tendon of the extensor hallucis brevis. ConclusionThe extensor hallucis longus demonstrates great variability in the approach of its tendon to the foot, at least in fetuses, as indicated by this initial classification.

Clinical results of distal anterior tibial tendon decompression

BackgroundDistal tibialis anterior tendinopathy (DTAT) is condition which is infrequently described in literature and is usually treated with conservative means. If resistant to a rehabilitation protocol and unloading, a surgical treatment could be proposed. The aim of this research is to report on the history and clinical image of DTAT and present the clinical results of a simple surgical decompression of the tendon with local debridement and release of the distal extensor retinaculum. MethodsSeventeen patients diagnosed with DTAT in 18 feet underwent surgery between 2008 and 2018. Upon initial presentation, all patients reported a persistent history of pain over the tibialis anterior (TA) insertion. Ultrasound was routinely performed to confirm the diagnosis. In patients with confirmed diagnosis of DTAT, persistent despite conservative treatment, we proceeded with surgical intervention during which we released the tendon by opening the distal extensor retinaculum. Retrospective chart review was performed, and functional outcomes were assessed using the AOFAS midfoot score. AOFAS score results were collected postoperatively with at least one-year follow-up. ResultsAll patients experienced pain on palpation of the distal aspect of the TA tendon. Most patients experienced pain at night and were frequent hikers. Our study population consisted of mostly female and overweight patients. All patients reported pain relief with a significant improvement of VAS for pain from 6.7 ± 1.1 preoperatively to 1.1 ± 1.2 postoperatively (p < 0.05). The postoperative AOFAS midfoot score was 97 ± 3.7. Fifteen patients were completely satisfied, two satisfied with minor reservations. ConclusionSimple distal TA tendon release by division of a consistently present constricting distal extensor retinaculum represents a surgical alternative in the treatment of chronic DTAT. Our study shows good clinical outcomes with low complications. Level of EvidenceLevel IV – retrospective case series.

A biomechanical study of clamping technique on patellar tendon surface strain and material properties using digital image correlation

Several clamping techniques exist for ex vivo mechanical testing of tendon. For the patellar tendon, one can choose to clamp directly to the bony attachment sites, the tendon itself, or a combination of the two; however, the influence of these techniques on localized strains and gross material properties is unknown. To this end, uniaxial tensile tests were performed on eleven porcine patellar tendons in three clamping setups while digital image correlation was used to measure axial and transverse strains, Young's modulus, and Poisson's ratio. The setups involved clamping to: 1) the patella and tibia, 2) the patella and the dissected distal tendon, and 3) the dissected proximal and distal tendon. Axial strains in the tendon-tendon clamping setup were 181% higher than patella-tibia clamping (p = 0.002) and 131% higher than patella-tendon clamping (p = 0.006). Transverse strains were not significantly different between clamping conditions (p ≥ 0.118). Young's modulus was 50% (p < 0.001) greater for patella-tibia clamping and 42% (p < 0.001) greater for patella-tendon clamping when compared to tendon-tendon clamping. For all clamping setups, the tendon illustrated auxetic behaviour (i.e., negative Poisson's ratio); however, the Poisson's ratios were 80% smaller in the patella-tibia setup (p = 0.006) and 71% smaller patella-tendon setup (p = 0.007) compared to the tendon-tendon setup. These results illustrate that discretion should be utilized when reporting material properties derived from mechanical tests involving direct clamping to the dissected patellar tendon at both ends, as this clamping technique significantly increases axial strains, reduces Young's modulus, and alters the tendon's natural auxetic behaviour.

Simultaneous duplication of the tendon of plantaris with multiple tendinous connections into the crural fascia

The plantaris muscle (PM) typically begins with a short, fusiform muscle belly and continues as a slim tendon traversing distally between the gastrocnemius and soleus to attach into the calcaneus directly or Achilles tendon. Conventionally, it has been of most interest as a donor for surgeons plantaris tendon (PT) grafting and recent studies have implicated the PT in the development of Achilles tendinopathy. During routine cadaveric dissection, one such anatomical variation was identified in a cadaver with two distal tendons of the PM and also multiple tendon connections into the crural fascia. While similar variants have been reported before in isolation, to our knowledge, this has been rarely reported illustrating the coexistence of a duplicated PT with simultaneous fascial connections into the crural fascia. The clinical implications of such a finding are discussed.

Ultrasound of the distal biceps brachii tendon using four approaches: reproducibility and reader preference.

To determine which sonographic appearance of the distal biceps brachii tendon (DBBT) is preferred by readers, and if images obtained by two different operators are reproducible. We performed an IRB-approved prospective sonographic evaluation of the DBBT in 50 healthy elbows using four different approaches (anterior, lateral, medial, posterior) performed by two operators. Five musculoskeletal radiologists independently reviewed the images, and ranked the four approaches based on overall appearance of echogenicity of the tendon, visualized length, and visualization of the insertion. The medial approach was preferred in 79.6% of elbows, anterior in 17.6%, lateral in 2.8%, and the posterior approach was never preferred. The difference was statistically significant (P < 0.001). Kappa values for the five readers were 0.61 to 0.8 for choosing the images produced by the medial approach. The appearance of the DBBT using the medial approach is preferred by readers and is reproducible between different operators.

Mini-Open Distal Biceps Tendon Repair Using All-Suture Anchors

Distal biceps tendon ruptures are uncommon injuries that can cause impairment in range of motion and function. While distal bicep tendon repair to the radial tuberosity has been demonstrated to restore function and strength, there is a lack of consensus on the optimal technique. The purpose of this Technical Note and video is to provide our preferred method of repair using an open, onlay-tissue fixation with all-suture anchors (FiberTak; Arthrex) and anatomic positioning of the biceps tendon on the radial tuberosity.

Functional Outcomes and MRI Results Following Knotless Repair of Acute Achilles Tendon Ruptures

Category:Ankle; SportsIntroduction/Purpose:The surgical techniques for primary repair of acute Achilles tendon ruptures have evolved from large open incisions to mini-open and percutaneous techniques. Studies have demonstrated that lesser invasive surgical techniques may reduce the risk of post-operative wound complications. Knotless surgical repair of acute Achilles tendon ruptures can be performed through a mini-incision, but still permits a robust re-approximation of the tendon stumps and decreases suture burden through distal anchor fixation in the calcaneus. However, stress shielding and subsequent tendinosis of the distal tendon stump is a theoretical concern with this surgical technique. We hypothesize that our surgical technique allows for a durable repair through a minimally invasive approach, permitting a safe and accelerated rehabilitation protocol, excellent functional outcomes, and absence of distal stump tendinosis.Methods:A multicenter retrospective chart review was performed to identify all patients that underwent primary Achilles tendon repair using a knotless surgical technique with a minimum of one-year follow-up from three orthopedic foot and ankle surgeons’ practices. Exclusion criteria included: age <18, chronic Achilles tendon ruptures (>4 weeks), insertional Achilles tendon ruptures, revision Achilles surgery, peripheral neuropathy, and systemic inflammatory disease. All patients were contacted by phone and asked to return to the office for an MRI, clinical examination, and completion of functional outcome questionnaires. The primary outcome measure was the validated Achilles Tendon Total Rupture Score (ATRS). Secondary outcomes included the Visual Analog Score (VAS), postoperative complications, ankle range of motion, calf circumference, and single-heel rise. MRI was used to assess tendon continuity and healing, tendinosis, muscle atrophy, and bone marrow edema/stress fracture associated with anchor fixation in the calcaneus. MRI interpretation was performed by a single, blinded musculoskeletal radiologist.Results:Forty-three patients were identified with acute Achilles tendon ruptures. There were 36 patients (36/43, 84%) who underwent knotless Achilles tendon repair and agreed to participate in the study. The average time to clinical follow-up was 23.5 months (SD±16.3). The mean postoperative ATRS was 84.6 (SD±19.7). There was no significant difference in calf circumference (p=0.22), dorsiflexion (p=0.07), and plantarflexion (p=0.11) between the unaffected and surgical extremity at latest follow-up. One patient (1/36, 2.8%) experienced a re-rupture. There were no wound complications or neuritis. MRI was obtained in 26 patients (26/36, 72.2%) at an average of 17.5 months (SD±10.1). There were no MRI findings of distal stump tendinosis or calcaneal stress fractures. Thirty-two patients (32/36, 88.8%) returned to the same athletic activities one-year after surgery.Conclusion:There is paucity in the literature on functional outcomes following knotless Achilles tendon repair. In this multicenter study, we found that validated functional outcome scores and return to activity were similar to historical controls, with a low rate of surgical complications. MRI obtained in twenty-six patients (72.2%) at 17.5 months demonstrated an intact tendon without distal tendon stump stress shielding or calcaneal stress fracture. The knotless Achilles tendon repair is a unique surgical technique, minimizing suture burden and postoperative complications, while offering excellent functional outcomes and return to activity at two-year follow-up. The excellent clinical outcomes are corroborated by MRI.

Ultrasonographic Appearance of Elbow Joints in a Population of Amiata Donkeys

Ultrasound (US) is a well-established technique for investigating joint diseases in horses, complementary to radiography. Few studies have been performed on the ultrasonographic aspect of the elbow joint in horses and no reports are available on donkeys. The aim of this study is to describe the ultrasonographic appearance of the elbow joint in healthy donkeys. Descriptive cohort study included 34 elbow joints, which were evaluated in 17 donkeys. Inclusion criteria included no lameness or musculoskeletal diseases in the donkeys. The structures evaluated were the lateral and medial collateral ligaments, ulnaris lateralis proximal tendon, distal biceps brachii tendon, triceps brachii tendon, and the articular space. For each structure, one good-quality image was recorded. The structures were retrospectively assessed for echogenicity, fiber orientation, bone appearance, and shape. The prevalence of the visualized structures was calculated. Cohen κ coefficient was calculated for the repeatability (intraoperator agreement), the reproducibility (interoperator agreement), and the influence of the operator’s experience in US examination. The US appearance of the structures was described. Statistical analysis showed scarce-to-moderate agreement concerning the repeatability and mostly scarce-to-good agreement concerning the reproducibility of the US examination; finally, low-to-discrete agreement concerning the operator’s experience. Technical difficulties precluded an accurate description of the medial collateral ligament. The healthy animals included were limited. The US examination of the elbow joint in donkeys were similar to the features reported in horses. Individual experience partially influences the execution and the assessment of the US images.

Chronic Tear of the Distal Triceps Tendon Treated With Suture Anchors and Fascia Lata Allograft: Case Report, Surgical Technique and Literature Review

Chronic tears of the distal triceps tendon are extremely uncommon lesions. Surgical therapy can be performed with a direct reattachment of the 2 sides of the lesion or—in case of significant tendon retraction—using grafts to fill the resulting gap. Herein, we report a case of a torn distal triceps tendon that occurred in a 33-year-old patient suffering from paraplegia. The resulting functional impairment of the elbow impeded her to use a wheelchair, causing a substantial limitation to her mobility and autonomy. Preoperative clinical evaluation, x-rays, muscle-tendon ultrasound, and magnetic resonance imagingwas been performed. In consideration of a 6 cm retraction at the surgery, we reconstructed the tendon using a combination of suture anchors (5 mm Super Reevo ConMed) and a cadaver fascia lata allograft. After surgery, the elbow was immobilized in extension inside a brachio-metacarpal cast for 30 days. In the following month, the cast was replaced with a hinged elbow brace and progressive mobilization was permitted. Five months postoperatively, the patient regained her previous active flexion-extension articular ROM and was able to use her wheelchair again. No complication occurred.

Medial gastrocnemius muscle and tendon interaction during gait in typically developing children and children with cerebral palsy

1. Introduction Efficient gait is dependent on optimal interaction between muscles and tendons [1]. Pathological changes in the extensibility of the MG muscle fascicles, whole muscle-belly and Achilles tendon have been reported in children with spastic cerebral palsy (CP) [2]. Studying the relative length of these tissues during gait can improve our understanding of their dynamics and, inferably, the control strategies used in CP. In-vivo dynamic ultrasound imaging has been used to visualise the interaction between the MG muscle and tendon during 3D gait analysis. However, most studies combined ultrasound imaging of one variable (either fascicles or muscle-belly and tendon) with some form of musculoskeletal modelling to extrapolate the other variables, resulting in incomplete and variable findings [3–5]. 2. Research question How do MG muscle fascicles, belly, and Achilles tendon interact during gait in children with cerebral palsy (CP) and typically developing (TD) children? 3. Methods 3D gait analysis was carried out in six children with CP (11 ± 3 years, GMFCS I, uni/bilateral: 4/2) and six TD children (12 ± 4 years) as they walked at a comfortable walking speed (average CP: 0.5 m/s, TD: 1.0 m/s) on a treadmill. An ultrasound probe (Telemed SmartUS, 60 mm) was attached to the non-preferred (TD) or most-affected (CP) leg using a custom-made probe holder (Probefix Dynamic, USONO), whose position was tracked by motion analysis. Images were collected during walking first with the probe on the mid muscle-belly, imaging fascicles and secondly with the probe on the most distal muscle tendon junction (MTJ) to estimate both muscle-belly and tendon lengthchanges. Muscle-tendon unit (MTU) length-change represented combined muscle and tendon behaviour. Fascicle, MTU, muscle-belly and tendon length patterns were averaged over time-normalised gait cycles, and expressed relative to their lengths at initial contact [4]. Due to the small and heterogeneous sample, results are presented in a descriptive way. 4. Results Gait kinematic and kinetic data showed that the children with CP had mild gait deviations (1C-F). Children with CP showed reduced length-changes of all tissues compared to TD (Fig. 1A and B). In TD children, the tendon contributed more to MTU length-changes than muscle, as opposed to more equal contributions in CP. In TD children, the muscle-belly behaviour did not reflect the fascicle behaviour whereas in CP, muscle-belly and fascicle length patterns were similar. 5. Discussion Our initial findings of pathological tendon and muscle dynamics during CP gait are in line with a previous study imaging the MTJ [3], but less so with studies relying on modelling to estimate tendon length [4,5]. The similar length pattern between muscle-belly and fascicle in CP may indicate a stiff extracellular matrix. We highlight the importance of collecting experimental data from all three tissues in order to understand the pathology. This feasibility study needs to be confirmed once larger samples are collected.

Distal Biceps Brachii Tendon Insertion: A Simple Method of Ultrasound Evaluation.

Different ultrasound approaches have been proposed to evaluate the distal biceps brachii tendon, such as lateral, posterior, medial, and anterior, all allowing good visualization of the distal biceps tendon and its pathologic appearances. Here we describe a new method of ultrasound evaluation of the distal biceps tendon insertion with the patient in the so-called crab position. The crab position is used to evaluate the posterior compartment of the elbow but also the lateral and medial compartments. This position allows for coverage of 75% the elbow in a single position, with less discomfort for the patient and a fair amount of saved time. In this position, after the evaluation of the common extensor tendon in the long axis, turning the transducer 90° and moving it distally allows for optimal visualization of the distal biceps brachii tendon in the axial plane. It is a simple, quick approach that allows for excellent visualization of the insertion of the distal biceps brachii tendon while avoiding an anisotropic effect.

Acoustic Radiation Force Impulse (ARFI) elastography imaging of equine distal forelimb flexor structures

ABSTRACT This study set out to determine normal values for acoustic radiation force impulse (ARFI) elastography of the superficial digital flexor tendon, deep digital flexor tendon, accessory ligament of the deep digital flexor tendon and suspensory ligament in horses. Twenty-four horses were submitted to conventional sonographic assessment and elastography imaging (quantitative ARFI method) of distal forelimb tendons and ligaments at nine anatomical regions. Elastograms depicted tendons and ligaments in orange to red tones consistent with greater stiffness. Shear wave velocity was higher in the longitudinal compared to the cross-sectional plane but did not differ significantly between the left and right forelimbs. The suspensory ligament was stiffer compared to remaining structures in the cross-sectional plane. Ligaments were stiffer than tendons and the deep digital flexor tendon was stiffer than the superficial digital flexor tendon in the longitudinal plane. Target structures were stiffer in male compared to female horses and stiffness tended to increase with age. ARFI elastography proved to be a feasible and reproducible imaging modality for assessment of distal forelimb tendons and ligaments in horses. Qualitative features derived from stiffness quantification in these structures can be applied to horses with musculoskeletal disorders, as well as to other animal species.

Morphometric analysis of all 24 hip muscles: A cadaveric study of 18 hip specimens with proposal of a new classification of muscles.

There are few papers investigating the morphometry of hip muscles and reporting either a single muscle or a group of synergistic muscles. With the development of hip joint simulation, hip arthroplasty implants, and gait analysis, a set of biometric data covering all the muscles that act on the hip joint is needed. Using a rigorous dissection process on 18 cadaveric hips, measurements of all 24 hip muscles and bone parameters were conducted. We measured the following: (a) total femur, femoral shaft, and neck lengths, (b) total muscle lengths, (c) intra-muscular and extra-muscular (free) tendon lengths, (d) bone angles, (e) muscle pennation, sagittal, and frontal angles, (f) muscle weight, (g) muscle volume, (h) muscle cross-sectional area, and (i) and bending moment. Data on more than 12,000 morphometric or anatomical parameters were collected. Correlation values between bone variables, muscle variables, and in-between muscle variables were computed. Based on their compliance, muscles were classified using the ratio of belly length over the sum of intra-muscular and free tendons. Values of the neck, shaft, and total femur lengths were highly correlated in relation to each other. The long muscles and the pelvitrochanteric muscles were highly correlated with femoral bone lengths. The proximal and distal intra-muscular tendon lengths were correlated to the total muscle length for all long muscles, independently of free tendon (extra-muscular) or muscle belly lengths. A very significant correlation was found between muscle weight variations among specimens. Three groups of muscles were identified based on their compliance. This is the first comprehensive anatomical morphometric study which includes all the 24 muscles acting on the hip joint. It generates a unique anatomical dataset comprising all necessary data for musculoskeletal modeling and arthroplasty implants of the hip joint. A new muscle classification was proposed based on compliance where muscles of the same group would exhibit similar compliance and functional anatomy.

Relativity of the Conventional Hand Tendon Zones and the Actual Glide Zones of Tendon Injury and Repair: A Need for Concept Reappraisal.

The conventional hand tendon zones and subzones do not reflect the actual lengths covered by the involved locus of the tendon during full digital and wrist motion, which warrant reappraisal of the tendon zone concept. Because of the tendon excursions many lacerations should be regarded as multiple zone injuries. Furthermore, the length-spans of glide of the distal tendon stump and of the tendon junction (i.e. the glide zones of tendon injury and repair, respectively) are mostly not of the same length because, due to pulley release and bulkiness of the tenorrhaphy, the glide zone of tendon repair is shorter than that of tendon injury. Therefore, it would be practical to notate the glide zones of the lacerated tendon by indicating the anatomic position of the distal tendon stump and tendon junction in full extension and flexion. This data can be provided separately or along with the conventional tendon zones, e.g. II (A4-C2) or II-III (A2-PA), where A, C, and PA stand for the annular, cruciform, and palmar aponeurosis pulleys, respectively. The conventional tendon zone classification could be improved with a tendon glide zone concept. Documentation of the actual excursions of the distal tendon stump and of the tenorrhaphy interface would prevent misinterpretation of the actual level of tendon injury and repair.