Associations Between the Size of Individual Plantar Intrinsic and Extrinsic Foot Muscles and Toe Flexor Strength

Background The size of the plantar intrinsic and extrinsic foot muscles has been shown to be associated with toe flexor strength (TFS). Previous studies adopted the size of a limited plantar intrinsic foot muscle or a compartment containing several muscles as an independent variable for TFS. Among the plantar intrinsic and extrinsic foot muscles, therefore, it is unclear which muscle(s) primarily contributes to TFS development. The present study aimed to clarify this subject. Methods In 17 young adult men, a series of anatomical cross-sectional area of individual plantar intrinsic and extrinsic foot muscles was obtained along the foot length and the lower leg length, respectively, using the magnetic resonance imaging. Maximal anatomical cross-sectional area (ACSAmax) and muscle volume (MV) for each constituent muscle of the plantar intrinsic foot muscles (flexor hallucis brevis; flexor digitorum brevis, FDB; abductor hallucis; adductor hallucis oblique head, ADDH-OH; adductor hallucis transverse head, ADDH-TH; abductor digiti minimi; quadratus plantae) and extrinsic foot muscles (flexor hallucis longus; flexor digitorum longus) were measured. TFS was measured with a toe grip dynamometry. Results TFS was significantly associated with the ACSAmax for each of the ADDH-OH (r = 0.674, p = 0.003), ADDH-TH (r = 0.523, p = 0.031), and FDB (r = 0.492, p = 0.045), and the MV of the ADDH-OH (r = 0.582, p = 0.014). As for the ADDH-OH, the correlation coefficient with TFS was not statistically different between ACSAmax and MV (p = 0.189). Stepwise regression analysis indicated that ACSAmax and MV of the ADDH-OH alone explained 42% and 29%, respectively, of the variance in TFS. Conclusion The ADDH-OH is the key muscle that primarily contributes to TFS development among the plantar intrinsic and extrinsic foot muscles.

Radiological study of Os trigonum and its clinical significance

Background: Os trigonum (OST) is commonly located on the posterior aspect of the talus. It occurs as a result of secondary ossification center failing to fuse with the lateral tubercle of the posterior process of the talus; its incidence varies between 2 and 25%, and is more often bilateral. It occurs as an intra-articular Os, which is most often securely rooted to the lateral tubercle of the talus by a fibrocartilaginous synchondrosis. Aims and Objective: To determine the incidence, morphology, and distribution of Os Trigonum (OST). Materials and Methods: Retrospective 500 lateral foot radiographs view were studied to determine the incidence, morphology, and distribution of OST. Results: Incidence of OST in the present study was 6.6%, with predominantly round or ovoid in shape. OST was located on the posterolateral aspect of the talus. Conclusion: OST can be one of the causative factor responsible for Flexor hallucis longus tendonitis, OST syndrome, which occur in plantarflexion of the ankle, leading to compression of the OST between the distal tibia and the calcaneus. Hence, knowledge regarding the incidence, morphology, and distribution of OST is important for the radiologist, orthopedic surgeons to arrive at a correct diagnosis, which aids in the management of cases presenting with complaints of posterior ankle pain.

Ultrasound-Guided Musculoskeletal Injections

Musculoskeletal injections serve a variety of diagnostic and therapeutic purposes, with ultrasonography (US) guidance having many advantages: no ionizing radiation, real-time guidance, high spatial resolution, excellent soft tissue contrast, and the ability to identify and avoid critical structures. Sonography can be cost effective and afford flexibility in resource-constrained settings. This article describes US-guided musculoskeletal injections relevant to many radiology practices and provides experience-based suggestions. Structures covered include multiple joints (shoulder, hip), bursae (iliopsoas, subacromial-subdeltoid, greater trochanteric), peripheral nerves (sciatic, radial), and tendon sheaths (posterior tibial, peroneal, flexor hallucis longus, Achilles, long head of the biceps). Trigger point and similar targeted steroid injections, as well as calcific tendinopathy barbotage, are also described.

Migratory Loose Bodies from the Ankle Joint into the Flexor Hallucis Longus Tendon Sheath

Objective: Loose bodies resulting from any form of osteochondral insult can migrate out of their intra-articular position to adjacent compartments. This retrospective study aims to illustrate the phenomenon of loose bodies migration from the ankle joint into the flexor hallucis longus (FHL) tendon sheath. Materials and Methods: Cases of loose bodies in the FHL tendon sheath were identified from the authors' radiological database by way of keyword interrogation, covering the modalities of CT, MRI, and ultrasound over a period of 11 years. The imaging features of the loose bodies were recorded, together with the presence of ankle instability and osteoarthritis. Patient demographics and relevant history, including trauma and surgery, were collected. Results: Thirty-four cases including 33 patients, with a total of 125 loose bodies in the FHL tendon sheath, were identified. There were 58 loose bodies (46.4%) in Zone 1 of the FHL tendon sheath, 65 loose bodies (52%) in Zone 2, and 2 loose bodies (1.6%) in Zone 3. All patients had features of ankle osteoarthritis on imaging, 14 of which had imaging features of ankle instability, and 19 patients had previous ankle trauma. Conclusion: Osteochondral loose bodies originating from the ankle joint can migrate into the FHL tendon sheath. It is important to recognise this phenomenon as a distinct entity, different from primary tenosynovial chondromatosis of the FHL tendon sheath, which may have a different surgical management and clinical outcome. Detection of FHL tendon sheath loose bodies should also prompt closer examination for articular disease in the ankle joint.

Irregularity in Plantar Fascia, Muscle Edema and Tendon Thickness in Patients with High-Risk for Diabetic Foot

Aim To investigate the alterations in the plantar fascia (PF), intrinsic muscles, and tendons in the feet of patients at high risk for developing diabetic foot. Methods The healthy feet of 22 patients with type 2 diabetes, who had developed diabetic foot ulcers on a single foot without any pathology on the contralateral extremity, and those of 22 healthy volunteers were evaluated by magnetic resonance imaging. The volume of the Achilles tendon (AT), the surface area of the PF, the thickness of AT, flexor hallucis longus, flexor digitorum longus, tibialis posterior, and peroneus longus tendons, irregularity in the PF, and edema of intrinsic foot muscles were examined. Results Nineteen patients (86%) had irregularity in the PF, whereas none of the healthy controls had any (p<0.001). Intrinsic muscle edema was more common in the group with diabetes (p=0.006). The volume of AT and the surface area of PF were decreased in patients with peripheral arterial disease (PAD) (p<0.05). Patients with diabetes mellitus but without PAD had a larger surface area of PF than that of controls (p<0.05). There were no differences in the volume of AT, the surface area of the PF, and other tendon thickness between the groups. Conclusion Irregularity in the PF and muscle edema may indicate a high risk for the diabetic foot. The presence of PAD may lead to regression in the structure of AT and PF.

Biomechanical Analysis of Single Interference Screw vs Interference Screw With Cortical Button for Flexor Hallucis Longus Transfer

Background: Flexor hallucis longus tendon transfer (FHL) with a cortical button tension slide is an innovative addition that has not been measured against traditional methods. Methods: 12 pairs (n=24) of fresh-frozen cadaveric tibia-to-toe samples were used and randomized to receive one of the operative FHL techniques. Specimens underwent bone density analysis. Biomechanical loading was applied between 20 and 60 N at 1 Hz for 100 cycles. Post–cyclic load to failure occurred at 1.25 mm/s. Cyclic displacement, structural stiffness, and ultimate load were derived from load-displacement curves. Student t tests evaluated significant effects between both FHL techniques. Linear regression analysis assessed interactions between bone density and strength of FHL technique. Results: Average tendon diameter was 5.44±0.46 mm. Average bone density was 1.06±0.08 g/cm2. Addition of a cortical button to FHL transfer did not significantly affect cyclic displacement (0.78±0.52 mm vs 0.87±0.80 mm) or structural stiffness (162.11±43.34 N/mm vs 167.57±49.19 N/mm). Cortical button addition to FHL transfer resulted in significantly increased ultimate load (343.72±68.93 N) compared with interference screw alone (255.62±77.17 N) ( P = .0002). Linear regression analyses did not reveal any significant interactions between bone density and FHL tendon transfer technique. Conclusion: Enhanced strength can be achieved with FHL tendon transfer to calcaneus using an interference screw and cortical button tension slide technique as compared to an interference screw alone. Cortical buttons in the setting of FHL tendon transfer to the calcaneus offers an additional level of support. Clinical Relevance: Operative cases presenting with poor bone quality due to osteoporosis or osteopenia could benefit from cortical button fixation during FHL transfer. Clinical studies are needed to determine if the increased construct stability conferred from the additional use of a flip button results in fewer FHL transfer failures or better clinical outcomes. Level of Evidence: Level V, Controlled Laboratory Study.

Endoscopic Flexor Hallucis Longus Transfer for the Management of Acute Achilles Tendon Ruptures in Professional Soccer Players

Background: Acute Achilles tendon ruptures (AATRs) that occur in athletes can be a career-ending injury. The aim of this study was to describe return to play and clinical outcomes of isolated endoscopic flexor hallucis longus (FHL) transfer in active soccer players with AATR. Methods: Twenty-seven active male soccer players who underwent endoscopically assisted FHL tendon transfer for acute Achilles tendon ruptures were included in this study. Follow up was 46.2 (±10.9) months after surgery. Return to play criteria and clinical outcome measures were evaluated. Results: All players returned to playing professional competitive soccer games. Return to active team training was at a mean of 5.8 (±1.1) months postoperatively. However, return to active competitive match play occurred at a mean of 8.3 (±1.4) months. Twenty-two players (82%) were able to return to their preinjury levels and performances and resumed their professional careers at the same soccer club as their preinjury state. One player (3.7%) shifted his career to professional indoor soccer. At 26 months postoperatively, the mean Tegner activity scale score was 9.7 (±0.4), the mean Achilles tendon total rupture score was 99 (±2), and the mean American Orthopaedic Foot & Ankle Society ankle-hindfoot score was 99 (±3). No patients reported any great toe complaints or symptomatic deficits of flexion strength. Conclusion: The current study demonstrated satisfactory and comparable return to play criteria and clinical results with minimal complications when using an advanced endoscopically assisted technique involving FHL tendon transfer to treat acute Achilles tendon ruptures in this specific subset of patient cohort. Level of Evidence: Level II, prospective cohort case series study.

Rehabilitative ultrasound imaging for the assessment of selected morphometric parameters of the flexor hallucis longus muscle in healthy individuals: An inter- and intra- rater reliability study

IntroductionUltrasound imaging (USI) is useful to evaluate structures of the foot to guide treatment, but the reliability of USI technique needs to be clarified. The goal of the study was to evaluate the intra- and inter-examiner reliability of USI image capture, and measurement of the cross-sectional area (CSA) and thickness of the flexor hallucis longus (FHL) for experienced and novice examinersMaterial and methodsFHL images were captured for 20 healthy adults. Reliability of image capture was evaluated between images repeated at 10-min interval for an experienced and a novice examiner. Reliability of image-based measurements was evaluated for one experienced and one novice rater, using all images. The intra-class correlation coefficient (ICC) and the standard error of measurement (SEM) were calculatedResultsIntra-examiner reliability of image capture for the FHL muscle examined by USI was excellent for both thickness (ICC3,1, 0.944–0.976; SEM, 6.8%–10.0%) and CSA (ICC3,1, 0.954–0.979; SEM, 10.8%–16.5%), with no effect of examiner experience. Reliability was also excellent for measurement of thickness (ICC3,1, 0.954–0.972; SEM, 1.2%–9.6%) and CSA (ICC3,1, 0.961–0.986; SEM, 9.2%–14.1%), with no effects of experience.ConclusionsReliability of image capture and image-based measurements developed by USI of CSA and thickness for the FHL muscle in healthy individuals was excellent, independent of the examiner experience.

Post-traumatic digital flexion contracture (checkrein deformity)

Objective: The aim of this study is to present a series of 8 patients, describing their clinical picture and assessing their treatment using plantar approach. Methods: We retrospectively assessed 8 patients, all of which had a history of trauma. The clinical characteristics of these cases and postoperative results were investigated. Results: Seven men and 1 woman with a mean age of 29 years were included. The follow-up period ranged from 6 to 28 months (mean 22 months). The deformity manifested from 5 to 24 months after the triggering injuries (mean 9.8 months). The hallux was the only digit affected in 1 patient, while the others presented with involvement of 1 or more small toes. There were no postoperative complications, and patients showed to be satisfied with functional outcomes. Conclusion: Post-traumatic digital flexion contracture is an infrequent disease of unknown etiology. Lengthening of the flexor hallucis longus using a plantar approach, whether at the level of the midfoot or the toe, represents an alternative with satisfactory outcomes. Level of Evidence IV; Therapeutic Study; Case Series.