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Concept: Peroneus longus

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The aim of this study was to investigate the association between foot type and the morphometry of selected muscles and tendons of the lower limb. Sixty-one healthy participants (31 male, 30 female; aged 27.1 ± 8.8 years) underwent gray-scale musculoskeletal ultrasound examination to determine the anterior-posterior (AP) thickness of tibialis anterior, tibialis posterior, and peroneus longus muscles and tendons as well as the Achilles tendon. Foot type was classified based on arch height and footprint measurements. Potentially confounding variables (height, weight, hip and waist circumference, rearfoot and ankle joint range of motion, and levels of physical activity) were also measured. Multiple linear regression models were used to determine the association between foot type with muscle and tendon morphometry accounting for potentially confounding variables. Foot type was significantly and independently associated with AP thickness of the tibialis anterior tendon, peroneus longus muscle, and Achilles tendon, accounting for approximately 7% to 16% of the variation. Flat-arched feet were associated with a thicker tibialis anterior tendon, a thicker peroneus longus muscle, and a thinner Achilles tendon. Foot type is associated with morphometry of tendons that control sagittal plane motion of the rearfoot; and the peroneus longus muscle that controls frontal plane motion of the rearfoot. These findings may be related to differences in tendon loading during gait.

Concepts: Regression analysis, Linear regression, Foot, Muscle, Tibialis anterior muscle, Tibialis posterior muscle, Tendon, Peroneus longus

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PURPOSE: To examine the anatomy of the lateral ankle after arthroscopic repair of the lateral ligament complex (anterior talofibular ligament [ATFL] and calcaneofibular ligament [CFL]) with regard to structures at risk. METHODS: Ten lower extremity cadaveric specimens were obtained and were screened for gross anatomic defects and pre-existing ankle laxity. The ATFL and CFL were sectioned from the fibula by an open technique. Standard anterolateral and anteromedial arthroscopy portals were made. An additional portal was created 2 cm distal to the anterolateral portal. The articular surface of the fibula was identified, and the ATFL and CFL were freed from the superficial and deeper tissues. Suture anchors were placed in the fibula at the ATFL and CFL origins and were used to repair the origin of the lateral collateral structures. The distance from the suture knot to several local anatomic structures was measured. Measurements were taken by 2 separate observers, and the results were averaged. RESULTS: Several anatomic structures lie in close proximity to the ATFL and CFL sutures. The ATFL sutures entrapped 9 of 55 structures, and no anatomic structures were inadvertently entrapped by the CFL sutures. The proximity of the peroneus tertius and the extensor tendons to the ATFL makes them at highest risk of entrapment, but the proximity of the intermediate branch of the superficial peroneal nerve (when present) is a risk with significant morbidity. CONCLUSIONS: Our results indicate that the peroneus tertius and extensor tendons have the highest risk for entrapment and show the smallest mean distances from the anchor knot to the identified structure. Careful attention to these structures, as well as the superficial peroneal nerve, is mandatory to prevent entrapment of tendons and nerves when one is attempting arthroscopic lateral ankle ligament reconstruction. CLINICAL RELEVANCE: Defining the anatomic location and proximity of the intervening structures adjacent to the lateral ligament complex of the ankle may help clarify the anatomic safe zone through which arthroscopic repair of the lateral ligament complex can be safely performed.

Concepts: Skeletal system, Anatomy, Ligament, Distance, Ankle, Sprained ankle, Peroneus longus, Anterior talofibular ligament

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Peroneal tendon pathology is often found in patients complaining of lateral ankle pain and instability. Conditions encountered include tendinosis; tendinopathy; tenosynovitis; tears of the peroneus brevis, peroneus longus, and both tendons; subluxation and dislocation; and painful os peroneum syndrome. Injuries can be acute as a result of trauma or present as chronic problems, often in patients with predisposing structural components such as hindfoot varus, lateral ligamentous instability, an enlarged peroneal tubercle, and a symptomatic os peroneum. Treatment begins with nonoperative care, but when surgery is required, reported results and return to sport are in general very good.

Concepts: Tendon, Tendinitis, Peroneus longus

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Sport-related pubalgia is often a diagnostic challenge in elite athletes. While scientific attention has focused on adults, there is little data on adolescents. Cadaveric and imaging studies identify a secondary ossification centre located along the anteromedial corner of pubis beneath the insertions of symphysial joint capsule and adductor longus tendon. Little is known about this apophysis and its response to chronic stress.

Concepts: Medicine, Stress, Pubis, Peroneus longus, Mons pubis, Adductor longus muscle

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Peroneal intrasheath instability is a painful snapping condition of the lateral ankle. It consists of a transient retromalleolar subluxation of the peroneal tendons without disruption of the superior peroneal retinaculum or evidence of a previous definite trauma. In type A intrasheath instability, the peroneus longus and brevis tendons are intact, and there is an intertendinous intrasheath switch. In type B intrasheath instability, the peroneus brevis tendon has a longitudinal split tear through which the peroneus longus subluxates. Both types can be missed on a physical examination because there is no displacement of the peroneal tendons over the lateral malleolus. Dynamic ultrasound is the imaging modality of choice for evaluating retromalleolar subluxation of the peroneal tendons. This review article aims to provide an overview of the anatomic basis for peroneal intrasheath instability and provide physicians with guidelines for its ultrasound assessment.

Concepts: Physical examination, Tendon, Ankle, Type, Type system, Peroneus longus, Peroneus brevis, Muscles of the lower limb

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To evaluate the normal location of the peroneus longus tendon (PL) in the cuboid groove in various ankle-foot positions by ultrasonography in asymptomatic volunteers.

Concepts: The Normal, Peroneus longus

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Rupture of the peroneus longus tendon with or without an associated os peroneum fracture is rare and uncommonly encountered in the published data. Owing to the infrequent nature, a high index of suspicion is required. Otherwise, the opportunity for the injury to result in a delayed or missed diagnosis is increased. We report the case of a 39-year-old male with spontaneous rupture of the peroneus longus tendon and associated fracture of the os peroneum. The spontaneous rupture and fracture were diagnosed from the history, physical examination, and imaging findings. The patient elected to undergo operative repair, with excellent results, full recovery, and full return to normal function.

Concepts: Diagnosis, Medical diagnosis, Set theory, Physical examination, The Opportunity, Peroneus longus

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Objective To compare three surgical techniques for lateral ankle ligament reconstruction using finite element (FE) models. Methods A three-dimensional FE model of the left foot of a healthy volunteer and lateral collateral ligament injury models were developed. Three tendons [one-half of the autologous peroneus longus tendon (PLT), one-half of the peroneus brevis tendon (PBT), and an allogeneic tendon] were used for lateral collateral ligament reconstruction. The ankle varus stress and anterior drawer tests were performed to compare the three surgical techniques. Results The ankle varus stress test showed that the equivalent stresses of the anterior talofibular ligament (ATFL) (84.00 MPa) and calcaneofibular ligament (CFL) (27.01 MPa) were lower in allogeneic tendon reconstruction than in the other two techniques but similar to those of normal individuals (138.48 and 25.90 MPa, respectively). The anterior drawer test showed that the equivalent stresses of the ATFL and CFL in autologous PLT reconstruction (31.31 and 28.60 MPa, respectively) and PBT reconstruction (31.47 and 29.07 MPa, respectively) were lower than those in allogeneic tendon reconstruction (57.32 and 52.20 MPa, respectively). Conclusions The allogeneic tendon reconstruction outcome was similar to normal individuals. Allogeneic tendon reconstruction may be superior for lateral ankle ligament reconstruction without considering its complications.

Concepts: Ligament, Tendon, Ankle, Sprained ankle, Posterior cruciate ligament, Drawer test, Peroneus longus, Peroneus brevis

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Chronic ankle instability (CAI) patients exhibit altered gait mechanics. The objective was to identify differences in stride-to-stride variability in the position of the center of pressure (COP) and muscle activity during walking between individuals with and without CAI. Participants (17 CAI;17 Healthy) walked on a treadmill at 1.3 m/s while surface electromyography (sEMG) of the fibularis longus (FL) and plantar pressure were recorded. The medial-lateral COP position was averaged for each 10% interval of stance and group standard deviations (SD), coefficient of variation (COV), and range for the COP position were compared between groups via independent t-tests. Ensemble curves for sEMG amplitude SD were graphed for the entire stride cycle to determine significant differences. The CAI group had increased COP position variability (SD (CAI = 0.79 ± 0.47 mm, Control = 0.48 ± 0.17 mm), COV (CAI = 1.47 ± 0.87 mm, Control = 0.93 ± 0.33 mm), range (CAI = 2.97 ± 2.07 mm, Control = 1.72 ± 0.33 mm, P < .05 for all analyses)) during the first 10% of stance. The CAI group had lower FL sEMG amplitude variability from 1 to 10% (mean difference = 0.014 ± 0.006), 32-38% (mean difference = 0.013 ± 0.004) and 56-100% (mean difference = 0.026 ± 0.01) of the gait cycle. Increased COP variability at initial contact may increase risk of lateral ankle sprains in CAI patients. Decreased sEMG amplitude variability may indicate a constrained sensorimotor system contributing to an inability to adapt to changing environmental demands.

Concepts: Statistics, Electromyography, Mean, Standard deviation, Walking, Statistical dispersion, Peroneus longus, The Cop

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OBJECTIVE The sciatic nerve, particularly its peroneal division, is at risk for injury during total hip arthroplasty (THA), especially when a posterior approach is used. The majority of the morbidity results from the loss of peroneal nerve-innervated muscle function. Approximately one-third of patients recover spontaneously. The objectives of this study were to report the outcomes of distal decompression of the peroneal nerve at the fibular tunnel following sciatic nerve injury secondary to THA and to attempt to identify predictors of a positive surgical outcome. METHODS A retrospective study of all patients who underwent peroneal decompression for the indication of sciatic nerve injury following THA at the Mayo Clinic or Washington University School of Medicine in St. Louis was performed. Patients with less than 6 months of postoperative follow-up were excluded. The primary outcome was dorsiflexion strength at latest follow-up. Univariate and multivariate logistic regression analyses were performed to assess the ability of the independent variables to predict a good surgical outcome. RESULTS The total included cohort consisted of 37 patients. The median preoperative dorsiflexion grade at the time of peroneal decompression was 0. Dorsiflexion at latest follow-up was Medical Research Council (MRC) ≥ 3 for 24 (65%) patients. Dorsiflexion recovered to MRC ≥ 4- for 15 (41%) patients. In multivariate logistic regression analysis, motor unit potentials in the tibialis anterior (OR 19.84, 95% CI 2.44-364.05; p = 0.004) and in the peroneus longus (OR 8.68, 95% CI 1.05-135.53; p = 0.04) on preoperative electromyography were significant predictors of a good surgical outcome. CONCLUSIONS After performing peroneal nerve decompression at the fibular tunnel, 65% of the patients in this study recovered dorsiflexion strength of MRC ≥ 3 at latest follow-up, potentially representing a significant improvement over the natural history.

Concepts: Regression analysis, Logistic regression, Muscle, Prediction, Hip replacement, Common fibular nerve, Dorsiflexion, Peroneus longus