Flouroscopic arthrography versus MR arthrography of the lesser metatarsophalangeal joints for the detection of tears of the plantar plate and joint capsule: a prospective comparative study

SSR white paper: guidelines for utilization and performance of direct MR arthrography

OBJECTIVE

Direct magnetic resonance arthrography (dMRA) is often considered the most accurate imaging modality for the evaluation of intra-articular structures, but utilization and performance vary widely without consensus. The purpose of this white paper is to develop consensus recommendations on behalf of the Society of Skeletal Radiology (SSR) based on published literature and expert opinion.

MATERIALS AND METHODS

The Standards and Guidelines Committee of the SSR identified guidelines for utilization and performance of dMRA as an important topic for study and invited all SSR members with expertise and interest to volunteer for the white paper panel. This panel was tasked with determining an outline, reviewing the relevant literature, preparing a written document summarizing the issues and controversies, and providing recommendations.

RESULTS

Twelve SSR members with expertise in dMRA formed the ad hoc white paper authorship committee. The published literature on dMRA was reviewed and summarized, focusing on clinical indications, technical considerations, safety, imaging protocols, complications, controversies, and gaps in knowledge. Recommendations for the utilization and performance of dMRA in the shoulder, elbow, wrist, hip, knee, and ankle/foot regions were developed in group consensus.

CONCLUSION

Although direct MR arthrography has been previously used for a wide variety of clinical indications, the authorship panel recommends more selective application of this minimally invasive procedure. At present, direct MR arthrography remains an important procedure in the armamentarium of the musculoskeletal radiologist and is especially valuable when conventional MRI is indeterminant or results are discrepant with clinical evaluation.

Normal and Diseased Imaging: Ultrasound/MRI

The lesser metatarsophalangeal joint plantar plate and calcaneonavicular (spring) ligament are highly specialized soft tissue structures within the foot, consisting partly of fibrocartilage and capable of withstanding high compressive and tensile loads. Preoperative advanced imaging, in the form of point-of-care ultrasound and MRI, has become indispensable for surgeons hoping to confirm, quantify, and better localize injuries to these structures before surgery. This article describes the technical considerations of ultrasound and MRI and provides examples of the normal and abnormal appearances of these structures. The pros and cons of each imaging modality are also discussed.

MR imaging-anatomical correlation of the metatarsophalangeal joint of the hallux: Ligaments, tendons, and muscles

OBJECTIVE

To perform an MR imaging-anatomical correlation to elucidate the anatomy of muscles, tendons, and ligaments about the hallux as seen on MR imaging.

MATERIALS AND METHODS

Four fresh and 4 embalmed cadaver specimens were used for this study. The embalmed specimens and one fresh specimen were dissected by three investigators. The fresh specimens were preserved deep frozen. They were thawed and imaged with a 3 T MR system. Proton density weighted images were obtained. The specimens were refrozen and sectioned with a band saw into 3 mm thick slices.

RESULTS

Musculotendinous structures were equally well seen in the fresh and embalmed specimens. The capsular ligaments could best be studied in the fresh specimens. Proximal to the sesamoids the following muscle and tendon anatomy was delineated: the abductor hallucis tendon inserted on the medial sesamoid bone together with the medial belly of the flexor digitorum brevis; the adductor hallucis (transverse and oblique heads) inserted on the lateral sesamoid together with the lateral head of the flexor hallucis brevis. At the level of the sesamoid bones and distally, the ligaments making up the plantar plate were delineated, including the presesamoid band, the flexor hallucis longus pulley, the sesamometatarsal ligaments, the sesamophalangeal ligaments, and the capsular ligaments.

CONCLUSION

MRI allows for accurate assessment of the complex anatomy of the hallux. At the level proximal to the sesamoids the muscle and tendon insertions are well demonstrated. At the level of the sesamoids and distally, the ligaments making up 'the plantar plate' are well demonstrated.

Lesser Metatarsophalangeal Joint Instability: Advancements in Plantar Plate Reconstruction

The plantar plate and associated collateral ligaments are the main stabilizers of each of the lesser metatarsophalangeal joints. Although clinical examination and plain radiographs are usually sufficient to establish the diagnosis of a plantar plate tear, MRI or fluoroscopic arthrograms may help in specific cases. Recent results with a dorsal approach to plantar plate repair are promising with respect to pain relief and patient satisfaction.

Evaluation of lesser metatarsophalangeal joint plantar plate tears with contrast-enhanced and fat-suppressed MRI

OBJECTIVE

To present findings of plantar plate (PP) lesions from MRI with administration of gadolinium and to differentiate PP lesions from others causes of metatarsalgia.

MATERIALS AND METHODS

Two musculoskeletal radiologists reviewed 249 contrast-enhanced forefoot MRI scans from patients with metatarsalgia between June 2012 and June 2013. Evaluations focused on hyper-vascularized/fibrous tissue and other findings associated with PP tears.

RESULTS

Fifty-nine patients had PP tears, 59 % were female. Most of these patients, 48/59 (81.4 %), had a single metatarsophalangeal (MTP) PP lesion in one foot, although 7/59 patients had one lesion in each foot, 3/59 (5.1 %) had two in one foot, and 1/59 (1.7 %) had three lesions in one foot. The second MTP joint was the most common location for PP tears (n = 56), followed by the third (n = 12) and fourth (n = 3) MTP joints. Lateral (n = 33) and full thickness (n = 28) PP lesions were the most frequent, and central (n = 3) and lateral/central (n = 7) tears were less prevalent. Fifty (70.5 %) PP lesions showed pericapsular fibrosis in pre-contrast sequences, and 21 (29.5 %) were visible only after administration of gadolinium. All PP lesions had collateral ligament involvement. Others findings included interosseous tendon lesions (n = 29), interosseous tendon rupture (n = 29), synovitis (n = 49), flexor tenosynovitis (n = 28), crossover toe (n = 2), hammertoe (n = 1), intermetatarsal space (IS) neuromas (n = 11), and third IS neuromas (n = 12).

CONCLUSION

PP tears are a common cause of metatarsalgia, accounting for more than 20 % of cases in our sample. A substantial portion of the lesions (29.5 %) became visible only after the administration of gadolinium.

Accuracy of palpation-directed intra-articular glenohumeral injection confirmed by magnetic resonance arthrography

PURPOSE

The aim of this study was to determine the accuracy of anatomic palpation-directed injections in the office setting.

METHODS

Two hundred twenty-six shoulders in 208 patients were studied using a 0.2-Tesla extremity scanner after the injection of gadolinium-diethylene triamine pentaacetic acid-saline. All patients were injected in a sterile fashion by a single board-certified shoulder surgeon using an anterior approach by palpating the rotator interval anterior to the acromioclavicular joint and angling the needle 45° lateral and 45° caudad. All injections, successful or otherwise, were single injections. Magnetic resonance (MR) arthrograms were retrospectively read by 2 musculoskeletal fellowship-trained, board certified radiologists to determine whether the injection was in the glenohumeral joint.

RESULTS

Two hundred one of the 226 injections were successful (88.9%). Of the 25 unsuccessful injections, the contrast material extravasated out of the capsule in 5 cases and into the subscapularis tendon in 10 cases. The contrast material was injected into the subacromial space in 9 cases, into the rotator interval fat in 9 cases, and into extracapsular tissue in 6 cases. There was insufficient volume of contrast material in 10 cases. The accuracy rate was 88.9%. There were no complications.

CONCLUSIONS

The palpation-directed rotator interval anterior approach technique for intra-articular glenohumeral MR arthrogram injections performed by a single surgeon was 88.9% accurate.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

MRI of lesser metatarsophalangeal joint plantar plate tears and associated adjacent interspace lesions

OBJECTIVE

To identify the variety of second and third intermetatarsal space (IS) lesions that may coexist with and without adjacent metatarsophalangeal joint (MTP) plantar plate (PP) tears.

MATERIALS AND METHODS

One hundred forefoot MRIs in 96 patients with metatarsalgia obtained between 30 September 2011 and 21 July 2012 using 1.5- or 3-T MRI were retrospectively reviewed in consensus by two MSK radiologists and one podiatrist (DPM). MRI was evaluated for second and third MTP PP tear and the presence/nature of second and third IS lesions. Second and third IS neuromas were measured in transverse (trans) dimension.

RESULTS

A total of 40 PP tears were identified: 36 at the second and 4 at the third MTP. Second MTP PP tear was identified in 33% of females and 40.5% of males. In the 63 female feet there were 21 second MTP PP tears, all of which also had second IS lesions: pericapsular fibrosis (16), bursitis (4), and ganglion (1). In the 37 male feet there were 15 second MTP PP tears, 14 of which had second IS lesions: pericapsular fibrosis (8), bursitis (5), and ganglion (1). There was no definite second IS neuroma adjacent to any second MTP PP tear. In females without PP tear, there were 24 second (3 mm trans average) and 43 third IS neuromas (4.1 mm trans average). In males without PP tear, there were 9 second (3.4 mm trans average) and 16 third IS neuromas (4.1 mm trans average).

CONCLUSIONS

MTP PP tears occurred in 40% of our cases, 90% of which occurred at the second MTP. Almost all coexisted with non-neuromatous second IS lesions.