Ultrasound of talocalcaneal coalition: retrospective study of 11 patients

Diagnostic value of high-frequency ultrasonography for painful talocalcaneal coalition and its complications

OBJECTIVE

To investigate the value of high-frequency ultrasonography in the diagnosis of painful talocalcaneal coalition (TCC) and its complications.

METHODS

Seventy-seven patients (84 feet) with abnormal mass and pain in the medial malleolus were suspected of TCC pre-operatively and examined by high-frequency ultrasonography, radiograph, and CT. The sonographic characteristics of the affected feet were analyzed pre-operatively and compared with the surgical findings.

RESULTS

During the operation, 49 feet with TCC and 35 feet with non-TCC were confirmed; pre-operative ultrasonography diagnosed 48 feet with TCC and 36 feet with non-TCC; taking surgery as the gold-standard, the sensitivity, specificity, accuracy, positive-predictive value and negative-predictive value of ultrasound diagnosis of TCC were 87.8%, 85.7%, 86.9%, 89.6%, and 83.3%, respectively. The two were consistent, with κ = 0.732, p < 0.001. High-frequency ultrasonography had high diagnostic efficacy for TCC, with an area under the receiver operating characteristic curve of 0.867. The accuracy of ultrasound and CT in the diagnosis of TCC was significantly higher than that of radiograph, and the difference was statistically significant (p < 0.0167). High-frequency ultrasound could also accurately diagnose complications of TCC, such as tibial nerve compression and tendon displacement, while CT and radiograph cannot show these complications.

CONCLUSION

High-frequency ultrasonography can accurately diagnose TCC and its complications, and locate the body surface accurately. Therefore, high-frequency ultrasonography can be used as a routine examination method to supplement CT and provide clinical assistance in precise surgery.

ADVANCES IN KNOWLEDGE

This study is the first to use high-frequency ultrasonography to examine TCC and compare its findings with surgical results to explore the diagnostic value of ultrasonography for TCC and its complications.

Surgical Treatment of Calcaneonavicular and Talocalcaneal Coalitions

Tarsal coalition is determined by an absence of segmentation between one or more foot bones. The main symptom is activity-related foot pain, usually dorsolateral for calcaneonavicular coalitions and medial for talocalcaneal ones. At presentation, a symptomatic tarsal coalition must be treated conservatively for at least 6 months. If the conservative treatment fails and the foot is still painful, resection is the treatment of choice. Advantage of surgery is to restore mobility and reduce the risk of subsequent degenerative arthritis. Common pitfalls of surgery include failure to recognize associated coalitions, inadequate or extensive resection, and injury of adjoining bones.

The role of ultrasonography in the diagnosis of talocalcaneal coalitions

BACKGROUND

Patients with talocalcaneal coalitions (TCC) often undergo computed tomography (CT). However, ultrasonography diagnosis of TCC has been seldom done according to the literature.

PURPOSE

To investigate the accuracy of ultrasonography in diagnosing TCC compared to CT.

MATERIAL AND METHODS

Ninety-seven consecutive patients with a clinical suspicion of TCC were included. Ultrasonography was used to assess the classification and complication of TCC. The main sonographic criteria for a positive diagnosis in cases of osseous coalition were the joint space between the medial surface of talar head and the underlying sustentaculum tali of calcaneus disappearing and being replaced by a continuous hyperechoic bony structure. In cases of fibrous coalition, ultrasonography revealed a reduced space of the joint associated with an irregular, angular appearance of its outline and hypoechoic fibrous tissue inside. These data were compared with CT findings. κ statistic was applied to determine the level of agreement. The sensitivity, specificity, positive and negative predictive values, accuracy, and Youden index of ultrasonography as a diagnostic method were assessed.

RESULTS

Ultrasonography findings were positive in 20 of 97 patients with a clinical suspicion of TCC. The diagnosis was confirmed by CT in 21 patients. There were one false-positive result and two false-negative results by ultrasonography. The κ value was 0.907. The sensitivity, specificity, positive and negative predictive values, accuracy, and Youden index of ultrasonography were 90.5%, 98.7%, 95.0%, 97.4%, 96.9%, and 0.892, respectively.

CONCLUSION

Ultrasonography could be a reliable, accurate, and non-radioactive diagnostic imaging method in diagnosis of patients with suspected TCC.

Ultrasound and bone: a pictorial review

The assessment of bone mainly relies on standard radiographs, CT, MRI, and bone scintigraphy depending on the anatomic region complexity and clinical scenario. Ultrasound (US), due to different acoustic impedance between soft tissues and the bone cortex, only allows the evaluation of the bone surfaces. Nevertheless, US can be useful in the evaluation of several bone disorders affecting the limbs as a result of its tomographic capabilities and high definition. This pictorial review article summarises our clinical experience in adults and reviews the literature on US bone examination. We first present the US appearance of normal bone and the main congenital anatomic variations, after which we illustrate the US findings of a variety of bone disorders. Although US has limits in bone assessment, its analysis must be a part of every musculoskeletal US examination.

Tarsal tunnel disease and talocalcaneal coalition: MRI features

OBJECTIVE

To assess, utilizing MRI, tarsal tunnel disease in patients with talocalcaneal coalitions. To the best of our knowledge, this has only anecdotally been described before.

MATERIALS AND METHODS

Sixty-seven ankle MRIs with talocalcaneal coalition were retrospectively reviewed for disease of tendons and nerves of the tarsal tunnel. Interobserver variability in diagnosing tendon disease was performed in 30 of the 67 cases. Tarsal tunnel nerves were also evaluated in a control group of 20 consecutive ankle MRIs.

RESULTS

Entrapment of the flexor hallucis longus tendon (FHL) by osseous excrescences was seen in 14 of 67 cases (21 %). Attenuation, split tearing, tenosynovitis, or tendinosis of the FHL was present in 26 cases (39 %). Attenuation or tenosynovitis was seen in the flexor digitorum longus tendon (FDL) in 18 cases (27 %). Tenosynovitis or split tearing of the posterior tibial tendon (PT) was present in nine cases (13 %). Interobserver variability ranged from 100 % to slight depending on the tendon and type of disease. Intense increased signal and caliber of the medial plantar nerve (MPN), indicative of neuritis, was seen in 6 of the 67 cases (9 %). Mildly increased T2 signal of the MPN was seen in 15 (22 %) and in 14 (70 %) of the control group.

CONCLUSIONS

Talocalcaneal coalitions may be associated with tarsal tunnel soft tissue abnormalities affecting, in decreasing order, the FHL, FDL, and PT tendons, as well as the MPN. This information should be provided to the referring physician in order to guide treatment and improve post-surgical outcome.

A Different Type of Talocalcaneal Coalition With Os Sustentaculum: The Continued Necessity of Revision of Classification

OBJECTIVE

The objective of our study was to retrospectively determine the prevalence and image findings of extraarticular talocalcaneal coalition with os sustentaculum, a type of talocalcaneal coalition that does not appear in current classification systems, in patients with an imaging diagnosis of foot coalition.

MATERIALS AND METHODS

This study was performed using a database query of radiology reports of ankle and foot CT or MRI examinations performed from August 2001 to November 2013. Eighty-one patients were identified through a keyword search of the database for "talocalcaneal coalition," "tarsal coalition," "coalition," or "os sustentaculum." Imaging features of CT or MRI findings were evaluated. Chart review was used to identify demographic information.

RESULTS

Extraarticular talocalcaneal coalition with os sustentaculum was diagnosed in 13 patients (nine men, four women), which represents a prevalence of 16.0% (13/81) in all foot coalitions and 24.1% (13/54) in all talocalcaneal coalitions. Four of 13 patients underwent surgical resection, and histology was obtained in three patients. Nine patients who had no history of trauma were symptomatic and all patients with bone marrow edema at the coalition sites on MRI (n = 5) were also symptomatic. Coexisting extraarticular talocalcaneal coalition with os sustentaculum and intraarticular talocalcaneal coalition were observed in 11 of 13 patients.

CONCLUSION

The os sustentaculum is a component of extraarticular talocalcaneal coalitions and as such is usually related to the presence of symptoms. If a patient with an os sustentaculum has symptoms in the medial talocalcaneal joint area, an extraarticular talocalcaneal coalition related to the os sustentaculum should be considered.

Imaging of the subtalar joint

Imaging of the subtalar joint can be challenging because of its complex planar anatomy. This article reviews the anatomy and common anatomic variants as seen with different imaging techniques. Although radiography remains the initial mode of imaging, computed tomography and MRI are frequently needed to better delineate the joint anatomy and improve the sensitivity and the specificity of detection of joint pathology. A short review of arthrographic techniques and various examples of imaging of common pathology involving this joint are also included.