The Achilles tendon insertion is crescent-shaped: an in vitro anatomic investigation.
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ABSTRACT:
SUBMITTER: Lohrer H
PROVIDER: S-EPMC2492990 | biostudies-other | 2008 Sep
REPOSITORIES: biostudies-other
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Project description:The Achilles tendon is a common tendon for the medial and lateral gastrocnemius and soleus muscles. Non-uniform Achilles tendon regional displacements have been observed in vivo which may result from non-uniform muscle loading and intra-tendinous shearing. However, prior observations are limited to the sagittal plane. This study investigated Achilles tendon tissue displacement patterns during isometric plantarflexor contractions in the coronal and sagittal planes. Fourteen subjects (5 female, 9 male, 26±3 yr) performed maximal isometric plantarflexor contractions with the knee in full extension and flexed to 110°. An ultrasound transducer positioned over the free Achilles tendon collected beam formed radio frequency (RF) data at 70 frames/s. Localized tissue displacements were analyzed using a speckle tracking algorithm. We observed non-uniform Achilles tendon tissue displacements in both imaging planes. Knee joint posture had no significant effect on tissue displacement patterns in either imaging plane. The non-uniform Achilles tendon tissue displacements during loading may arise from the anatomical organization of the sub-tendons associated with the three heads of the triceps surae. The biplanar investigation suggests that greatest displacements are localized to tissue likely to belong to soleus sub-tendon. This study adds novel information with possible implications for muscle coordination, function and muscle-tendon injury mechanisms.
| S-EPMC6472705 | biostudies-literature
Project description:The Achilles tendon exhibits anatomical variations in subtendon twist among individuals, and its compliance can change due to conditions like Achilles tendinopathy. However, current musculoskeletal models overlook these material and morphological variations. This study aimed to investigate the impact of altering Achilles subtendon insertion points and compliance on the triceps surae muscle forces, and therefore tendon loading, during dynamic exercises in one Achilles tendinopathy patient. First, subtendon insertion points were altered in the musculoskeletal model based on a subject-specific 3D freehand ultrasound model and for three types of subtendon twists: low, medium, and high. Second, tendon compliance was modeled based on experimental values, creating three musculoskeletal models: compliant, mean, and stiff. Results indicated that tendon compliance had a larger effect than tendon twist on triceps surae muscle forces. Altering subtendon insertion points to the three types of twist showed a maximal change of 2.3% in muscle force contribution compared to the no-twist model. During the eccentric rehabilitation exercise-a common exercise choice during rehabilitation-the compliant tendon model showed substantial differences compared to the generic (control) musculoskeletal model, resulting in decreased gastrocnemius medialis (-3.5%) and gastrocnemius lateralis (-3.2%) contributions and increased soleus contribution (+ 6.6%). Our study results highlight the necessity of incorporating tendon compliance in musculoskeletal models to accurately predict triceps surae muscle forces, especially in individuals with increased tendon compliance, such as patients with Achilles tendinopathy. Such findings contribute to more accurate predictions of muscle forces and hence, personalized rehabilitation strategies.
| S-EPMC11291231 | biostudies-literature
Project description:In the treatment of acute Achilles tendon rupture, recent studies demonstrate that conservative treatment with functional rehabilitation provides good results, with nearly identical postoperative rerupture rates when compared with surgical treatment. Surgical treatment is indicated in patients with particular conditions, such as patients who are young active athletes who require early return to play or those who wish to avoid the muscle atrophy associated with conservative methods. If surgery is the selected option for treatment, the postoperative complications of each type of surgery must be considered. In conventional open repair, the most common complication is soft-tissue infection due to the high tension of soft tissue affected from the bowstring of the repaired tendon being kept in the equinus position of the ankle. For percutaneous methods, sural nerve entrapment and injury are the most commonly reported complications. Other methods, including endoscopy, require technical expertise as well as special equipment. Several types of combination approaches have been explored in the literature. We describe a combined open and percutaneous technique to repair the Achilles tendon, called the hybrid Achilles tendon repair. This technique has been developed to provide a simplified and reproducible method of hybrid repair in which the complications of previous methods are avoided and which can be done without special equipment.
| S-EPMC6019910 | biostudies-literature
Project description:PurposeTo evaluate differences of Achilles tendon (AT) hardness and morphology between asymptomatic tendons in patients with acute AT ruptures on the contralateral side and asymptomatic tendons in healthy people by using computer-assisted quantification on axial-strain sonoelastography (ASE).MethodsThe study consisted of 33 asymptomatic tendons in 33 patients (study group) and 34 tendons in 19 healthy volunteers (control group). All the tendons were examined by both ASE and conventional ultrasound. Computer-assisted quantification on ASE was applied to extract hardness variables, including the mean (Hmean), 20th percentile (H20), median (H50) and skewness (Hsk) of the hardness within tendon, and the ratio of the mean hardness within tendon to that outside tendon (Hratio) and three morphological variables: the thickness (THK), cross-sectional area, and eccentricity (ECC) of tendons.ResultsThe Hmean, Hsk, H20, H50, and Hratio in the proximal third of the tendon body in study group were significantly smaller than those in control group (Hmean: 0.43±0.09 vs 0.50±0.07, p=0.001; Hsk: -0.53±0.51 vs -1.09±0.51, p<0.001; H20: 0.31±0.10 vs 0.40±0.10, p=0.001; H50: 0.45±0.10 vs 0.53±0.08, p<0.001; Hratio: 1.01±0.25 vs 1.20±0.23, p=0.003). The THK and cross-sectional area of tendons in the study group were larger than those in the control group (p<0.05).ConclusionsAs a quantitative objective method, the computer-assisted ASE reveals that the asymptomatic ATs contralateral to acute rupture are softer than those of healthy control group at the proximal third and the asymptomatic tendons in people with rupture history are thicker, larger, and rounder than those of normal volunteers especially at the middle and distal thirds of AT body.
| S-EPMC6304598 | biostudies-literature
Project description:Achilles tendon injuries have been on the rise secondary to our increased participation in sports, increase in societal obesity rates, and the growing elderly population. There has been disagreement in recent years about whether to treat injuries such as Achilles tendon ruptures operatively or nonoperatively with aggressive functional rehabilitation. For those opting to surgically manage Achilles tendon ruptures, insertional Achilles tendonitis, or augment the described SpeedBridge Achilles tendon repair, we propose a modified rip-stop technique. The goal of this technique is to provide a biomechanical advantage to our current operative interventions for these injuries, a greater load-to-failure and a speedier, more reliable return to sport in our athletic populations.
| S-EPMC8417224 | biostudies-literature
Project description:Superior capsular reconstruction (SCR) has become an increasingly popular choice in the treatment of massive, irreparable rotator cuff tears, pseudoparalysis, and in cases in which revision of previous rotator cuff repair is indicated. The SCR procedure is intended to restore the superior stabilizing forces of a deficient rotator cuff. This technique is accomplished by substituting an autograft or allograft between the superior glenoid and the greater tuberosity of the humerus, thus keeping the humeral head centered in the glenoid during shoulder forward flexion and abduction. Since its advent, numerous techniques have been described for this procedure. A fascia lata autograft was initially described; however, many surgeons in the United States have advocated for the use of a humeral dermal allograft. Yet, biomechanical studies have demonstrated elongation and thinning of this material. Thus, the Achilles tendon allograft may be an attractive choice for SCR, given its previous success with ligamentous and tendinous reconstructions. In this article, we present our technique of SCR using an Achilles tendon allograft.
| S-EPMC7189387 | biostudies-literature
Project description:Revision quadriceps tendon repair presents a challenging problem for the treating surgeon because of associated anatomic defects such as large tendon-gap deficits and preexistent poor tissue quality. Current methods for revision quadriceps tendon repair use tendon autograft, which may predispose to additional morbidity because the repair relies only on soft tissue fixation. In this Technical Note, we describe a technique for revision of a failed quadriceps tendon repair with a large tendon gap using a trapezoidal plug Achilles tendon allograft. This technique constitutes a safe and effective approach to revising failed primary quadriceps tendon repairs, is suitable for large-gap defects, and has the ability to withstand large force transmissions.
| S-EPMC6848963 | biostudies-literature
Project description:BackgroundInfection following Achilles tendon surgery is a devastating complication and can be difficult to treat and often leads to poor outcomes. A number of treatments have been described, but there is little information concerning outcomes of these treatments. Our purpose was to evaluate the clinical and functional outcomes of patients who have undergone treatment for an infected Achilles tendon after acute and chronic midsubstance repair.MethodsWe retrospectively reviewed the medical records of 20 patients who had undergone surgical treatment for an infected Achilles tendon between 2000 and 2016. The mean follow-up time was 21 months (range, 2-68 months). All patients underwent extensive debridement of the tendon with removal of all infected tissue and foreign material. Soft tissue wound coverage was utilized for large wounds that were not amenable to primary or secondary closure. All patients received culture-specific intravenous (IV) antibiotics for 3 to 6 weeks. Postoperatively, the extremity was immobilized in a splint followed by a cast until the wound was healed. The cast was then replaced with a walking boot and the patients were provided a physical therapy program. Functional outcomes were measured using the Foot and Ankle Ability Measure (FAAM) Activity of Daily Living (ADL) scale.ResultsAll wounds had healed at the time of last follow-up. Three patients (15%) required an unplanned return to the operating room for repeat debridement. All patients were able to walk without the use of a gait aid. Five patients (25%) required continued use of a boot or brace during ambulation. Fourteen patients participated in the FAAM ADL survey. There were 6 patients lost to follow-up. The average FAAM score was 87 (range, 71.4-100). At last follow-up, most patients reported their overall function as "normal" or "nearly normal." Eradication of infection and satisfactory functional results can be attained after radical debridement, wound closure, and administration of culture-specific IV antibiotics.Level of evidenceLevel IV, retrospective case series.
| S-EPMC8696926 | biostudies-literature
Project description:A 70-year-old man complained imbalance while walking, inability to perform ankle flexion, and could not stand on tip-toe 3 months after injury. The ankle looked swollen with loss of Achilles contour and obvious gait disturbance. Magnetic resonance imaging shows a 5-cm Achilles tendon gap. Subsequently, surgery was performed to solve the neglected Achilles tendon rupture. Patient was put under general anesthesia with a regional block. Using a non-tourniquet technique, a reconstructive procedure was performed using a half-width autologous Achilles tendon graft, which was attached to the calcaneal prominence with wire in a double strand Bunnell fashion. As for the proximal stump, double core Bunnell/modified Kessler suturing was carried out to suture the graft to Achilles stump. To increase the vascularization, an ipsilateral gastrocnemius fascial flap with a distally based-pedicle was harvested to wrap around the tendon graft. At a 6-month follow-up, the patient was able to stand on tip-toe and had also regained a normal gait.
| S-EPMC6536867 | biostudies-literature
Project description:BackgroundDuring the stance phase of running, the elasticity of the Achilles tendon enables the utilisation of elastic energy and allows beneficial contractile conditions for the triceps surae muscles. However, the effect of changes in tendon mechanical properties induced by chronic loading is still poorly understood. We tested the hypothesis that a training-induced increase in Achilles tendon stiffness would result in reduced tendon strain during the stance phase of running, which would reduce fascicle strains in the triceps surae muscles, particularly in the mono-articular soleus.MethodsEleven subjects were assigned to a training group performing isometric single-leg plantarflexion contractions three times per week for ten weeks, and another ten subjects formed a control group. Before and after the training period, Achilles tendon stiffness was estimated, and muscle-tendon mechanics were assessed during running at preferred speed using ultrasonography, kinematics and kinetics.ResultsAchilles tendon stiffness increased by 18% (P < 0.01) in the training group, but the associated reduction in strain seen during isometric contractions was not statistically significant. Tendon elongation during the stance phase of running was similar after training, but tendon recoil was reduced by 30% (P < 0.01), while estimated tendon force remained unchanged. Neither gastrocnemius medialis nor soleus fascicle shortening during stance was affected by training.DiscussionThese results show that a training-induced increase in Achilles tendon stiffness altered tendon behaviour during running. Despite training-induced changes in tendon mechanical properties and recoil behaviour, the data suggest that fascicle shortening patterns were preserved for the running speed that we examined. The asymmetrical changes in tendon strain patterns supports the notion that simple in-series models do not fully explain the mechanical output of the muscle-tendon unit during a complex task like running.
| S-EPMC6486809 | biostudies-literature