Founder's lecture of the ISS 2006: borderlands of normal and early pathological findings in MRI of the foot and ankle

Presurgical Perspective and Postsurgical Evaluation of Non-Achilles Tendons of the Ankle and Retinaculum

The vast majority of non-Achilles ankle tendinopathies are related to overuse. This article discusses the clinical aspect, imaging appearance, and management of tendinopathies of the lateral, medial, and the anterior compartments with a focus on presurgical perspective and postsurgical evaluation.

Peroneus Longus and Peroneus Brevis: A Review on Pathology and Updated Treatments

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Peroneus longus (PL) and peroneus brevis (PB) pathologies involve a variety of etiologies and degrees of dysfunction, which complicates their diagnoses.

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Patient presentation includes a spectrum of disease; however, despite advanced imaging, a misunderstanding of the pathology and diagnostic algorithms has contributed to continued misdiagnoses.

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This article summarizes the anatomy and the pathophysiology of the PL and the PB; it also provides updated treatment options and their associated outcomes in order to illuminate an often-misunderstood topic.

The Failed Deltoid Ligament in the Valgus Misaligned Ankle-How to Treat?

This article deals with the treatment of a chronically failed deltoid ligament complex in the valgus misaligned ankle. This is a challenging task in every orthopedic foot and ankle surgery. Before embarking on any surgery that relates to the deltoid ligament complex, it is mandatory to analyze any underlying cause that could promote the impairment. Once this is done, it might be of value in considering anatomic reconstructions. The article provides an anatomic reconstruction technique, which should help address the problem.

CT scan assessment of the dimensions and morphological variations of the peroneal tubercle

PURPOSE

The hypertrophied peroneal tubercle may result in lateral ankle pain with peroneal tendon tenosynovitis and rupture. The aim of this study was to evaluate different configurations and dimensions of the normal peroneal tubercle using two-dimensional CT scan.

METHODS

Totally, 100 normal CT scans of cases older than 18 years of age were assessed to determine the shape of the peroneal tubercle. Moreover, height, length and width of different configurations of the normal peroneal tubercle were measured in axial and coronal sections of the ankle CT scans.

RESULTS

Four different configurations based on the axial cut of the calcaneus were found; single-convex (59%), double-convex (24%), plateau (9%), and convex-concave (8%) without statistically significant difference between genders (p-value: 0.526). Totally, mean of height, length and width were 4.42 ± 1.38 mm, 28.88 ± 6.58 mm and 17.17 ± 3.85 mm, respectively. Although mean of the height in the single-convex and the double-convex types were 4.5 ± 1.4 mm and 5.0 ± 1.4 mm, respectively, the highest peroneal tubercle in the single-convex and the double-convex group were 10.2 mm and 8.5 mm, respectively.

CONCLUSIONS

In cases with lateral ankle pain and suspicious to hypertrophied peroneal tubercle, two-dimensional CT scan can be an available practical modality to identify the pathological type of the peroneal tubercle based on the presented classification and normal values. As previously reported in the literature, considering cut-off point of 5 mm could result in overdiagnosis of the hypertrophied peroneal tubercle, especially in single-convex type; however, clinical correlation is always paramount.

LEVEL OF EVIDENCE

Level IV.

Anteroposterior Radiograph of the Ankle with Cross-Sectional Imaging Correlation

The focus of this article is to illustrate various pathologic entities and variants, heralding disease about the ankle, based on scrutiny of AP radiographs of the ankle, with correlative findings on cross-sectional imaging. Many of these entities can only be detected on the AP ankle radiograph and, if not recognized, may lead to delayed diagnosis and persistent morbidity to the patient. However, a vigilant radiologist, equipped with the knowledge of the characteristic appearance and typical locations of the imaging findings, should be able to make the crucial initial diagnosis and surmise additional findings to be confirmed on cross-sectional imaging.

Endoscopic Resection of Peroneal Tubercle

Symptomatic hypertrophy of the peroneal tubercle can result in pain, clicking sensation, and limitation of ambulation. Surgical resection is indicated for symptomatic hypertrophied tubercle that is recalcitrant to conservative treatment. The purpose of this Technical Note is to report the details of tendoscopic resection of the hypertrophied peroneal tubercle. This is performed through zone 2 peroneus longus tendoscopy. Any associated hindfoot deformity and peroneal tendon pathology should also be addressed.

Surgical management of the peroneus quartus muscle for bilateral ankle pain: a case report

The peroneus quartus muscle is an accessory muscle seen in the lateral compartment of the lower leg. Although the peroneus quartus muscle is asymptomatic in general, it sometimes becomes pathologic. We present the rare case of bilateral ankle pain with crepitation caused by the peroneus quartus muscle. Magnetic resonance imaging should be considered to assist with diagnosing this condition. Foot and ankle surgeons should consider it in the preoperative differential diagnosis when patients present with posterior ankle pain.

Functional outcomes after peroneal tendoscopy in the treatment of peroneal tendon disorders

PURPOSE

The primary purpose of this study was to evaluate clinical outcomes following peroneal tendoscopy for the treatment of peroneal pathology. Correlation between pre-operative magnetic resonance imaging (MRI) and peroneal tendoscopic diagnostic findings was also assessed.

METHODS

Twenty-three patients with a mean age of 34 ± 8.8 years undergoing peroneal tendoscopy were pre- and post-operatively assessed with the foot and ankle outcome score (FAOS) and the Short Form-12 (SF-12) outcome questionnaires. Follow-up was over 24 months in all patients. The sensitivity and specificity of MRI were calculated in comparison with peroneal tendoscopy, including the positive predictive value (PPV).

RESULTS

Both the FAOS and the SF-12 improved significantly (p < 0.05) at a mean follow-up of 33 ± 7.3 months significantly. MRI showed an overall sensitivity of 0.90 (95% confidence interval (CI) = 0.82-0.95) and specificity of 0.72 (95% CI 0.62-0.80). The PPV for MRI diagnosis of peroneal tendon pathology was 0.76 (95% CI 0.68-0.83).

CONCLUSIONS

The current study found good clinical outcomes in patients with peroneal tendon disorders, treated with peroneal tendoscopy. Although a relatively small number of patients were included, the study suggests good correlation between tendoscopic findings and pre-operative MRI findings of peroneal tendon pathology, supporting the use of MRI as a useful diagnostic modality for suspected peroneal tendon disorders.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

High-resolution US and MR imaging of peroneal tendon injuries

Injuries of the peroneal tendon complex are common and should be considered in every patient who presents with chronic lateral ankle pain. These injuries occur as a result of trauma (including ankle sprains), in tendons with preexisting tendonopathy, and with repetitive microtrauma due to instability. The peroneus brevis and peroneus longus tendons are rarely torn simultaneously. Several anatomic variants, including a flat or convex fibular retromalleolar groove, hypertrophy of the peroneal tubercle at the lateral aspect of the calcaneus, an accessory peroneus quartus muscle, a low-lying peroneus brevis muscle belly, and an os peroneum, may predispose to peroneal tendon injuries. High-resolution 1.5-T and 3-T magnetic resonance (MR) imaging with use of dedicated extremity coils and high-resolution ultrasonography (US) with high-frequency linear transducers and dynamic imaging are proved to adequately depict the peroneal tendons for evaluation and can aid the orthopedic surgeon in injury management. An understanding of current treatment approaches for partial- and full-thickness peroneal tendon tears, subluxation and dislocation of these tendons with superior peroneal retinaculum (SPR) injuries, intrasheath subluxations, and peroneal tendonopathy and tenosynovitis can help physicians achieve a favorable outcome. Patients with low functional demands do well with conservative treatment, while those with high functional demands may benefit from surgery if nonsurgical treatment is unsuccessful. Radiologists should recognize the normal anatomy and specific pathologic conditions of the peroneal tendons at US and MR imaging and understand the various treatment options for peroneal tendon and SPR superior peroneal retinaculum injuries. Online supplemental material is available for this article.

Tenosynovitis of the peroneal tendons associated with a hypertrophic peroneal tubercle: radiography and MRI findings

An enlarged peroneal tubercle can cause a peroneal tendon tear and/or tenosynovitis due to chronic friction. We present the case of a 45-year-old man with tenosynovitis in the peroneus longus and brevis tendons associated with a hypertrophic peroneal tubercle. On admission to our facility, the patient presented with pain while walking and had a fixed mass on the lateral aspect of his right foot. In addition, an osseous prominence corresponding to a hypertrophic peroneal tubercle was seen on the lateral side of the right calcaneus on radiography. MRI confirmed the hypertrophic peroneal tubercle and revealed high-signal intensity within the peroneus longus and brevis tendons along with fluid in their sheaths.

Magnetic resonance imaging of ankle tendon pathology: benefits of additional axial short-tau inversion recovery imaging to reduce magic angle effects

OBJECTIVES

Our goals were to quantify the reduction of the magic angle effect using short-tau inversion recovery (STIR) imaging and to determine the value of adding an axial STIR sequence to the magnetic resonance imaging ankle protocol.

MATERIALS AND METHODS

Axial STIR sequences were used to measure normal tendon T1 and to estimate signal loss due to the inversion recovery preparation of our clinical protocol. In addition, 102 ankles were imaged with axial fat-suppressed intermediate-weighted fast spin echo and STIR sequences. Two radiologists analyzed the tendons for signal intensity, size, abnormalities, and magic angle effect. The diagnostic value and image quality of the two sequences were compared.

RESULTS

We calculated a 50% reduction of signal intensity in healthy tendons on the STIR sequence at TI = 170 ms compared with TI = 0 ms, explaining the decrease in the magic angle effect. Using the STIR sequence, our study demonstrated significantly lower signal intensity within the tendons, more precise tendon size, and a lower magic angle effect compared with the standard intermediate-weighted FSE sequence (p < 0.001). Diagnostic classification of tendon abnormalities using the STIR sequences showed higher sensitivity (82.35% vs. 75.27%) and better agreement with a reference standard than the intermediate-weighted sequences, and superior image quality (p < 0.01).

CONCLUSIONS

Axial STIR sequences reduce magic angle effects and improve visualization of ankle tendon pathology.

Endoscopic resection of the peroneal tubercle

Hypertrophy of the peroneal tubercle can be a source of discomfort when wearing shoes. Occasionally, it can cause tenosynovitis or a tear of the peroneal tendons. The symptoms can be successfully treated by complete resection of the tubercle, tenosynovectomy, and early range of motion exercises of the hindfoot joints. Traditionally, this is an open procedure. We report the technique of endoscopic resection of the peroneal tubercle.

Validity of the posterior tibial edema sign in posterior tibial tendon dysfunction

BACKGROUND

Posterior tibial tendon dysfunction (PTTD) is a common malady leading to acquired flatfoot, which frequently causes foot and ankle pain and swelling. We hypothesized that patients with PTTD and pitting edema along the course of the posterior tibial tendon (PTT) would have evidence of fluid within the tendon sheath on MRI. We introduce and validate a novel, yet simple physical examination finding, the posterior tibial edema (PTE) sign, to help distinguish PTTD from other causes of foot and ankle pain and swelling.

PATIENTS AND METHODS

To determine an association between the PTE sign and changes to the PTT evident on MRI, we reviewed the medical records of patients with PTTD who underwent magnetic resonance imaging (MRI).

RESULTS

Of 186 patients identified with PTTD, 49 underwent MRI, and 42 (86%) demonstrated imaging characteristics consistent with tendonitis, tendinosis, or tenosynovitis. Presence or absence of increased posterior malleolar pitting edema agreed with presence or absence of these MRI findings in 43 patients (88%), making the clinical examination finding significantly predictive of MRI results (p= 0.01). The sensitivity of the test for PTE was 86%, with specificity of 100%.

CONCLUSION

The PTE sign refers to pitting edema along the course of the PTT, not associated with acute trauma and not accompanied by other areas of edema. Physical examination signs that are highly sensitive and specific to the condition may help lower the cost of diagnosis by eliminating the need for expensive tests that are not always necessary.

Traumatic pathologies of the calcaneal peroneal tubercle

The peroneal tubercle occurs in about one half of human feet. It size varies from a small nodule of less than 1mm height to a prominent spur up to 1cm in size. It had been noted to cause stenosing tenosynovitis of the peroneal tendons, especially in association with an accessory peroneal bone. The current manuscript describes two cases of symptomatic tenosynovitis developing after an ankle sprain with fracture of the peroneal tubercle. The tenosynovitis caused dysfunction of the peroneal tendons unresponsive to prolonged conservative therapy. Symptoms were resolved following surgical resection.