MR imaging findings of entrapment of the flexor hallucis longus tendon

OBJECTIVE: In this retrospective study, we describe the MR imaging patterns of various causes of flexor hallucis longus tendon entrapment. CONCLUSION: Entrapment of the flexor hallucis longus tendon may be due to an enlarged os trigonumtarsitarsi, calcaneal fracture, and soft-tissue scar. These disorders have characteristic imaging findings that may be revealed on MR imaging.     

One-stage treatment of deep infection following repair of Achilles tendon rupture with flexor hallucis longus transfer

We present one-stage treatment of deep infection following repair of Achilles tendon rupture using flexor hallucis longus transfer. Flexor hallucis longus was used not only to connect the defect in Achillles tendon, but also to control the soft tissue infection with its abundant blood supply, simultaneously. The clinical results for the two patients in this report were excellent without major complication.     

Endoscopic assisted flexor hallucis tendon transfer in the management of chronic rupture of Achilles tendon

Operative treatment is indicated in the management of chronic Achilles tendon rupture. Reconstruction of chronic Achilles tendon rupture can be classified into end-to-end repair, tendo Achilles advancement or flap reconstruction, local tendon transfer and implantation with autografts, allografts or synthetic materials. Following debridement of the tendon ends and with retraction of the proximal tendon fragment, a large gap will be present and direct tendon apposition with physiological tension is usually not possible. Flexor hallucis longus transfer is indicated if the tendon gap is more than 5 cm. We describe an endoscopic assisted flexor hallucis longus transfer in order to minimize the soft tissue dissection.     

Chondroma within the flexor hallucis longus tendon sheath. A case report and literature review

Chondromas in tendon sheaths are a rare entity proviously reported in the flexor sheaths on the hand and possibly the foot. This is the first reported case of condroma of the flexor hallucis longus tendon sheath at the ankle region. A literature review with regard to pathogenesis, classification, and recurrence has been presented.     

A novel approach to flexor hallucis longus tenography

OBJECTIVE: This article presents a technically simple and more accurate approach to flexor hallucis longus (FHL) tenography than any we found reported in the literature. CONCLUSION: Tenography is used to evaluate and treat tenosynovitis. Standard FHL tenography protocol involves either direct percutaneous access of the FHL synovial sheath posterior to the medial malleolus or indirect filling of the FHL sheath from an injection of the flexor digitorum longus (FDL) tendon sheath, which often communicates with the FHL tendon sheath. However, with these methods, difficulty entering the FHL sheath may be encountered. We adapted our technique to access the FHL sheath as it courses below the sustentaculum talus. Our early experience with five cases using this technique reflects a 100% success rate with accurate needle placement within the FHL tendon sheath, thereby improving procedural efficiency.     

Tendons in the plantar aspect of the foot: MR imaging and anatomic correlation in cadavers

Objective: The purpose of this anatomic imaging study was to illustrate the normal complex anatomy of tendons of the plantar aspect of the ankle and foot using magnetic resonance (MR) imaging with anatomic correlation in cadavers. Design: Seven fresh cadaveric feet (obtained and used according to institutional guidelines, with informed consent from relatives of the deceased) were studied with intermediate-weighted fast-spin-echo MR imaging. For anatomic analysis, cadaveric specimens were sectioned in 3-mm-thick slices in the coronal and axial planes that approximated the sections acquired at MR imaging. Results: The entire courses of the tendons into the plantar aspect of the foot were analyzed. The tibialis posterior tendon has a complex distal insertion. The insertions in the navicular, second, and third cuneiforms bones were identify in all cases using axial and coronal planes. A tendinous connection between the flexor hallucis longus and the flexor digitorum longus tendons was identified in five of our specimens (71%). The coronal plane provided the best evaluation. The peroneus longus tendon changes its direction at three points then obliquely crosses the sole and inserts in the base of the first metatarsal bone and the plantar aspect of the first cuneiform. Conclusions: MR imaging provides detailed information about the anatomy of tendons in the plantar aspect of the ankle and foot. It allows analysis of their insertions and the intertendinous connection between the flexor hallucis longus and the flexor digitorum longus tendons.     

Tendon injuries of the foot and ankle.

Tendon injuries are often caused by direct trauma or overuse. Pathology may consist of inflammatory lesions external to the tendon sheath or inflammation of either the peritenon, sheath, or tendon. This article reviews the diagnosis and treatment of injuries to the peroneal, peroneus brevis, peroneus longus, anterior tibial, flexor hallucis longus, and posterior tibial tendons.     

MR imaging of the tarsal tunnel and related spaces: normal and abnormal findings with anatomic correlation

The tarsal tunnel syndrome may be caused by extrinsic or intrinsic pressure on the posterior tibial nerve or its terminal branches. The specific symptoms depend on the extent of nerve involvement, and compression distal or proximal to the tarsal tunnel may result in variants of the syndrome. To define better the capability of MR imaging for evaluating this entity, we performed MR imaging on three normal subjects and correlated the images with cryomicrotome sections. Six patients with symptoms suggestive of tarsal tunnel syndrome also were studied with MR. In all normal subjects, MR images showed the flexor retinaculum and the structures passing deep to the retinaculum: the tibialis posterior tendon, flexor digitorum longus tendon, flexor hallucis longus tendon, and the posterior tibial neurovascular bundle. The medial calcaneal sensory branch(es) and the medial and lateral plantar nerves also were delineated. Mechanical causes of compression were shown in all six symptomatic patients. The pathologic entities included two neurilemomas, tenosynovitis involving all three tendons, a ganglion cyst arising from the flexor hallucis longus tendon sheath, posttraumatic fibrosis, and post-traumatic fibrosis with associated posttraumatic neuroma. The MR findings were confirmed surgically in five cases. MR imaging can accurately depict the contents of the tarsal tunnel and the courses of the terminal branches of the posterior tibial nerve. In our small series, MR imaging accurately showed the lesions responsible for tarsal tunnel syndrome.     

Management of posterior tibial tendinitis in the athlete

Posterior tibial tendinitis in the young patient is relatively uncommon. However, when it occurs, it can be debilitatingand considerably limit athletic function. Aggressive nonoperative treatment is indicated initially. If this fails, tenosynovectomy can restore function and relieve pain. If the degree of tendon degeneration is extensive, primary repair and/or augmentation with flexor digitorum longus or flexor hallucis longus transfer will be necessary. While short term results are encouraging in patients overall, little is known about the long-term prognosis or the results in young, high-demand individuals.     

Relationship between foot muscle morphology and severity of pronated foot deformity and foot kinematics during gait: A preliminary study

BackgroundThe morphology of foot muscles that support the medial longitudinal arch differs between normal and pronated feet. The degree to which the difference depends on the severity of the pronated foot deformity is unclear. In the clinical setting, however, to reduce the pronated deformity, muscle-strengthening exercises are performed.Research questionDoes a relationship exist between foot muscle morphology and severity of the pronated foot deformity and foot kinematics during gait?MethodsUsing the six-item foot posture index (FPI-6), 26 study participants were assessed for their foot posture and divided into two groups of 13 participants each based on the FPI-6 score: pronated foot group (with a score of 6–9) and highly pronated foot group (with a score of 10–12). Select foot muscles were scanned with ultrasonography, and muscle thicknesses were measured. The following were the muscles of interest: abductor hallucis, flexor hallucis brevis and longus, flexor digitorum brevis and longus, and peroneus longus. Foot kinematic data during gait was collected using a three-dimensional motion capture system as a dynamic navicular drop.ResultsNo between-group differences were noted for muscle thickness and dynamic navicular drop. However, the abductor hallucis and flexor hallucis brevis thicknesses were correlated with the dynamic navicular drop, but not with the severity of the pronated foot deformity.SignificanceIn individuals with pronated foot deformity, more developed abductor hallucis and flexor hallucis brevis muscles may reduce the dynamic navicular drop that represents the degree of medial longitudinal arch deformation during the stance phase of gait.     

Diagnostic and therapeutic ankle tenography: outcomes and complications

OBJECTIVE: The purpose of our study was to evaluate tenography complications and outcomes in a large series. MATERIALS AND METHODS: Of 144 tenograms obtained consecutively from May 5, 1995, to March 17, 1997, 111 were located for at least a 6-month follow-up; 65 were posterior tibial, 39 peroneal, two anterior tibial, three flexor digitorum longus, and two flexor hallucis longus tenograms. Tenography was performed fluoroscopically with contrast material and anesthetic followed by steroid placement into tendon sheaths. RESULTS: Of 65 patients undergoing posterior tibial tenography, 31 (48%) had complete or near-complete symptom resolution; 17 (26%) had no relief. Seventeen patients (26%) had initial relief with the subsequent return of pain to the pretenography level. Of 39 patients undergoing peroneal tenography, 18 (46%) had complete or near-complete symptom resolution; 10 (26%) had no and 11 (28%) had initial relief with subsequent pretenography pain return. Of three patients undergoing flexor digitorum longus tenography, one had complete, one had no, and one had initial relief with complete pretenography pain return. One of two patients who underwent flexor hallucis longus tenography had no relief; the other had initial relief with complete pain return. Two patients who underwent anterior tibial tenography had complete pain relief. We found no correlation between degree of tenosynovitis shown radiographically and therapeutic improvement with anesthetic and steroid injection. Tenography complications included one posterior tibial tendon rupture (0.89%) and 14 patients with skin discoloration at the tendon sheath injection site. CONCLUSION: Forty-seven percent of surgical candidates whose condition was refractory to conservative therapy had complete or near-complete prolonged symptom relief after tenography. In appropriate patients, tenography is excellent therapy for tenosynovitis. Certain precautions make complications rare.     

The influence of flip angle on the magic angle effect

Objective. To assess the impact of flip angle with gradient sequences on the ”magic angle effect”. We characterized the magic angle effect in various gradient echo sequences and compared the signal- to-noise ratios present on these sequences with the signal-to-noise ratios of spin echo sequences. Design. Ten normal healthy volunteers were positioned such that the flexor hallucis longus tendon remained at approximately at 55° to the main magnetic field (the magic angle). The tendon was imaged by a conventional spin echo T1- and T2-weighted techniques and by a series of gradient techniques. Gradient sequences were altered by both TE and flip angle. Signal-to-noise measurements were obtained at segments of the flexor hallucis longus tendon demonstrating the magic angle effect to quantify the artifact. Signal-to-noise measurements were compared and statistical analysis performed. Similar measurements were taken of the anterior tibialis tendon as an internal control. Results and conclusions. We demonstrated the magic angle effect on all the gradient sequences. The intensity of the artifact was affected by both the TE and flip angle. Low TE values and a high flip angle demonstrated the greatest magic angle effect. At TE values less than 30 ms, a high flip angle will markedly increase the magic angle effect. Received: 6 December 1999 Revision requested: 31 March 2000 Revision received: 22 May 2000 Accepted: 23 May 2000     

Initial experience with visualizing hand and foot tendons by dual-energy computed tomography

PurposeTo assess the feasibility of visualizing hand and foot tendons by dual-energy computed tomography (CT).Methods and materialsTwenty patients who suffered from hand or feet pains were scanned on dual-source CT (Definition, Forchheim, Germany) with dual-energy mode at tube voltages of 140 and 80 kV and a corresponding ratio of 1:4 between tube currents. The reconstructed images were postprocessed by volume rendering techniques (VRT) and multiplanar reconstruction (MPR). All of the suspected lesions were confirmed by surgery or follow-up studies.ResultsTwelve patients (total of 24 hands and feet, respectively) were found to be normal and the other eight patients (total of nine hands and feet, respectively) were found abnormal. Dual-energy techniques are very useful in visualizing tendons of the hands and feet, such as flexor pollicis longus tendon, flexor digitorum superficialis/profundus tendon, Achilles tendon, extensor hallucis longus tendon, and extensor digitorum longus tendon, etc. It can depict the whole shape of the tendons and their fixation points clearly. Peroneus longus tendon in the sole of the foot was not displayed very well. The distal ends of metacarpophalangeal joints with extensor digitoium tendon and extensor pollicis longus tendon were poorly shown. The lesions of tendons such as the circuitry, thickening, and adherence were also shown clearly.ConclusionDual-energy CT offers a new method to visualize tendons of the hand and foot. It could clearly display both anatomical structures and pathologic changes of hand and foot tendons.     

Ankle tenography: a key to unexplained symptomatology. Part I: Normal tenographic anatomy

Fifty cadaver ankles were examined with ankle tenography. The normal tenographic appearance of the peroneus longus and brevis, posterior tibial, flexor digitorum longus, flexor hallucis longus, anterior tibialis, extensor hallucis longus, and extensor digitorum longus tendons and sheaths are described and illustrated for clinical reference. The baseline measurements and demonstration of the normal radiographic appearance of these tendons should assist in the evaluation of hindfoot foot disability and ankle pain.     

Tenosynovial osteochondromatosis of the tarsal tunnel

A case of tenosynovial osteochondromatosis in the tarsal tunnel in a 23-year-old man is presented. The lesion was treated surgically, and multiple osteochondromas were excised, which had no continuity with any tarsal bone or joint cavity but did with the sheaths of the flexor digitorum longus and flexor hallucis longus. Histologic examination of the lesion showed a fibrous capsule, hyaline cartilage and extensive areas of cancellous bone. Necrosis and mitosis were absent in the hyaline cartilage and there were no synovial nodules indicative of synovial metaplasia. The macroscopic findings showed "end-stage" tenosynovial osteochondromatosis. There was no evidence of recurrence 5 years after operation, and the patient remains free of symptoms.     

The morphology of foot soft tissues is associated with running shoe type in healthy recreational runners

Objectives

To determine the differences in the morphology of foot soft tissues between runners using different types of running shoes.

Correlation of morphologic and pathologic features of the various tendon groups around the ankle: MR imaging investigation

Objective

To determine if a statistical association exists between abnormalities in one ankle tendon group (i.e., peroneal, medial flexor, or Achilles) and those in another.

Materials and methods

A retrospective analysis of 1.5-T and 3-T MR ankle examinations in 100 patients conducted between November 1, 2011 and April 1, 2012 was performed. The cross-sectional areas and diameters of the ankle tendons—Achilles (ACH), peroneus brevis (PB) and longus (PL), tibialis posterior (TP), flexor digitorum longus (FDL), and flexor hallux longus (FHL)—were measured, and the results were correlated to determine any association with the presence of qualitative abnormalities (tenosynovitis, tendinosis, and tendon tearing).

Results

Subjects with larger diameters of the ACH tendon also revealed larger PL, TP, FDL, and FHL tendon diameters and sectional areas. Furthermore, subjects with larger PL tendons generally revealed larger flexor tendons and the same was also true when medial compartment tendons were individually assessed and measurements compared among the three of them. There was a statistically significant association with regard to the presence of tendon abnormalities (tendinosis, tenosynovitis, and tearing) in both the peroneal and medial flexor tendons. The presence of an abnormality in the ACH tendon correlated strongly with increasing diameters and areas of all the other ankle tendons except for the PB tendon.

Conclusions

There is an association between quantitative and qualitative abnormalities of one group of tendons when compared with the others with respect to the ACH, medial flexor, and peroneal tendons of the ankle, which is perhaps explained by a retinacular and fascial complex that anatomically connects the three groups.     

Reconstruction of neglected Achilles tendon rupture using the flexor hallucis tendon

Neglected ruptures of the Achilles tendon (AT) are not common and have a greater tendency to cause complications and to produce poorer functional results than fresh ruptures. Numerous surgical procedures have been described for the reconstruction of neglected AT ruptures. However, no report has been issued about an AT rupture neglected for more than 2 years. The authors reported about three patients (four tendons) with a neglected AT rupture of mean duration of 5 years, who were treated by interposed scar tissue repair combined with flexor hallucis longus tendon transfer. All patients experienced good clinical results and were satisfied with surgery. None of the authors received financial support for this study.     

The dorsal pedis artery as a new distal landmark for extramedullary tibial alignment in total knee arthroplasty

Purpose

It is better to use multiple anatomical landmarks to reduce errors in component alignment in total knee arthroplasty. Therefore, it is worthwhile to find a new landmark that can be used as an addition to conventional ones. Herein, we assessed the dorsal pedis artery as a new distal landmark for extramedullary tibial alignment.

Methods

Fifty-two ankles in patients undergoing total knee arthroplasty and 10 ankles in normal controls were included. Color Doppler ultrasonography was used to locate the dorsal pedis artery at the level of the ankle joint. Conventional landmarks, including the tibialis anterior tendon, the extensor hallucis longus tendon, the extensor digitorum longus tendon, and the malleolar centre, were also located on ultrasound images. The distances between the ankle centre and each landmark were measured and compared.

Results

The dorsal pedis artery was absent in 2 patients and impalpable but visible with ultrasonography in other 2 patients. The dorsal pedis artery was located anatomically closest to the ankle centre in patients (0.4 ± 3.4 mm lateral). Statistical analysis showed that the dorsal pedis artery, the extensor hallucis longus tendon, and the malleolar centre were located significantly closer to the ankle centre comparing with the extensor digitorum longus tendon and the tibialis anterior tendon in both patients and controls (p < 0.001).

Conclusions

As long as the dorsal pedis artery exists, it can be used as an addition to the conventional landmarks in total knee arthroplasty. Using this new landmark will help reduce errors in coronal plane alignment of tibial component.

Level of evidence

II.     

Classification of medial longitudinal arch kinematics during running and characteristics of foot muscle morphology in novice runners with pronated foot

BackgroundNovice runners with pronated feet are at an increased risk of running-related injuries. However, not all runners with pronated feet have increased foot pronation during running. Moreover, although foot muscle morphology is related to static foot alignment, the relationship between foot muscle morphology and foot kinematics during running remains unclear. We aimed to determine foot kinematic patterns during running among novice runners with pronated feet and the presence of a relationship between these foot kinematic patterns and foot muscle morphology.MethodsTwenty-one novice runners with pronated feet participated in this study, and data on 39 lower limbs were collected. Data on foot kinematics during running (rearfoot strike) were collected using a three-dimensional motion capture system in terms of navicular height (NH) at initial contact and dynamic navicular drop (DND). A hierarchical cluster analysis method was used to identify the optimal number of clusters based on these two foot-related kinematic variables. Following identification of the clusters, differences in cluster variables and cross-sectional areas of selected foot muscles assessed using ultrasonography in each cluster were examined. The muscles of interest included the abductor hallucis, flexor hallucis brevis and longus, flexor digitorum brevis and longus, and peroneus longus.ResultsThree subgroups were identified based on foot kinematics during running: cluster 1, lowest NH at initial contact and larger DND; cluster 2, moderate NH at initial contact and smaller DND; and cluster 3, highest NH at initial contact and larger DND. Clusters 1 and 3 had a larger abductor hallucis compared with cluster 2, and cluster 3 had a larger flexor hallucis brevis compared with cluster 2.SignificanceThese subgroups may differ in terms of resistance to and type of running-related injury. Moreover, foot kinematics during running is possibly impacted by the morphology and function of medial intrinsic foot muscles.