MR imaging as a problem solving tool in posterior ankle pain: A review

Foot pain in children and adolescents: a problem-based approach in musculoskeletal ultrasonography

Various etiologies and risk factors contribute to foot pain in children and adolescents, including conditions such as Kohler's disease, Sever's disease, Iselin's disease, rigid flat foot, accessory navicular, Freiberg's disease, sesamoiditis, os trigonum syndrome, and more. High-frequency musculoskeletal ultrasonography can show both the bone surface and the surrounding soft tissue clearly from various angles in real-time, thereby providing a higher level of detail that is helpful for identifying the etiology of foot pain and monitoring disease progression compared with other imaging modalities. This review provides an overview of the epidemiology, pathophysiology, clinical manifestations and characteristic ultrasonographic findings of select foot pain conditions in children and adolescents.

An Update on Posterior Tarsal Tunnel Syndrome

Posterior tarsal tunnel syndrome (PTTS) is an entrapment neuropathy due to compression of the tibial nerve or one of its terminal branches within the tarsal tunnel in the medial ankle. The tarsal tunnel is formed by the flexor retinaculum, while the floor is composed of the distal tibia, talus, and calcaneal bones. The tarsal tunnel contains a number of significant structures, including the tendons of 3 muscles as well as the posterior tibial artery, vein, and nerve. Focal compressive neuropathy of PTTS can originate from anything that physically restricts the volume of the tarsal tunnel. The variety of etiologies includes distinct movements of the foot, trauma, vascular disorders, soft tissue inflammation, diabetes mellitus, compression lesions, bony lesions, masses, lower extremity edema, and postoperative injury. Generally, compression of the posterior tibial nerve results in clinical findings consisting of numbness, burning, and painful paresthesia in the heel, medial ankle, and plantar surface of the foot. Diagnosis of PTTS can be made with the presence of a positive Tinel sign in combination with the physical symptoms of pain and numbness along the plantar and medial surfaces of the foot. Initially, patients are treated conservatively unless there are signs of muscle atrophy or motor nerve involvement. Conservative treatment includes activity modification, heat, cryotherapy, non-steroidal anti-inflammatory drugs, corticosteroid injections, opioids, GABA analog medications, tricyclic antidepressants, vitamin B-complex supplements, physical therapy, and custom orthotics. If PTTS is recalcitrant to conservative treatment, standard open surgical decompression of the flexor retinaculum is indicated. In recent years, a number of alternative minimally invasive treatment options have been investigated, but these studies have small sample sizes or were conducted on cadaveric models.

Causes of delayed diagnosis of posterior ankle impingement in the pediatric and adolescent population

PURPOSE

The purpose of this study was to identify and characterize various causes of delay in the diagnosis of posterior ankle impingement syndrome (PAIS) in pediatric patients.

METHODS

IRB approved prospective study of patients under 18 years who underwent arthroscopic surgery for the diagnosis of posterior ankle impingement after failed conservative treatment at a tertiary children's hospital. Radiographic findings were compared with an age-matched control group. Descriptive and inferential statistics were employed.

RESULTS

47 patients (61 ankles), mean age 13 years, had an average 14 months delay in diagnosis of PAIS from the initial presentation. 33 (70%) patients had seen multiple medical providers and given other diagnoses. 9 (19%) patients participated in ballet or soccer, and 16 (34%) patients had unrelated associated foot and ankle diagnoses. 25 (41%) of 61 ankles did not have pain on forced plantar flexion; all 61(100%) ankles had tenderness to palpation over the posterior ankle joint line. Radiographs were reported to be normal in 37/52 (71%) ankles, while MRI report did not mention the diagnosis in 20/41 (49%) studies. There was a significant difference in the MRI findings in the patient population when compared to the control group. Indication for surgery was failed conservative treatment. All 61 ankles had posterior ankle impingement pathology confirmed visually during arthroscopy. At average 15 months follow-up, there was significant improvement pre- to post-operatively (p<0.001) for both pain VAS (6.9-0.9) and AOFAS ankle-hindfoot scores (65-94).

CONCLUSION

Multiple clinical and imaging factors can lead to delayed diagnosis of posterior ankle impingement. An increased awareness about the features of PAIS is needed amongst medical providers involved in treating young patients.

Is there any effect of presence and size of os trigonum on flexor hallucis longus tendon lesions?

BACKGROUND

It was hypnotized that presence and larger size of os trigonum (OT) can affect flexor hallucis longus tendon (FHL), so tenosynovitis, degeneration and partial tear can be developed.

METHODS

A total of 98 (Study group: 50, Control: 48) subjects included to study and compered status of FHL lesions. Sagittal length and axial width of OT were measured on MRI to determine effect of OT on FHL lesions and correlated with arthroscopic findings.

RESULTS

FHL tenosynovitis (p: 0,025), degeneration (p: 0,01) and partial tear (p: 0.008) was identified statistically high in study group. Statistical analysis revealed that as length of OT increased, frequency of degeneration (p: 0.03) and partial tear (p: 0.00) of FHL increased.

CONCLUSION

Analyzes were showed that the presence of os trigonum had an important role on the FHL pathologies. Additional finding of study was to demonstrate that possibility of FHL lesion increased as length of OT extended.

LEVELS OF EVIDENCE

Level 3.

Endoscopic Approach to Posterior Ankle via Lateral Portals

Posterior ankle pain is a common foot and ankle problem faced by orthopaedic surgeons. It can have many causes, including posterior ankle joint pathologies (synovitis or osteochondral lesion), ankle impingement (posterior, posterolateral, or posteromedial), flexor hallucis longus pathologies, peroneal tendon problems, posterior tibial tendinopathy, Achilles tendon pathology, posterior subtalar tarsal coalition, or tarsal tunnel syndrome. Most of these pathologies can be managed effectively by an endoscopic approach. The classic endoscopic approach is the 2-portal posterior ankle endoscopy with the portals at the medial and lateral side of the Achilles tendon. This is performed with the patient in prone position. In this technical note, we describe the details of endoscopic approach to the posterior ankle via lateral portals. This allow flexibility of patient positioning (supine, prone, or lateral). It is particularly effective for the management of posteromedial ankle impingement without the risk of injury to the posterior tibial neurovascular bundle. Moreover, any concomitant peroneal tendon pathology can be managed via the same lateral portals.

Injection Techniques for Common Chronic Pain Conditions of the Foot: A Comprehensive Review

Purpose of Review

This is a comprehensive literature review of the available evidence and techniques of foot injections for chronic pain conditions. It briefly describes common foot chronic pain syndromes and then reviews available injection techniques for each of these syndromes, weighing the available evidence and comparing the available approaches.

Recent Findings

Foot and ankle pain affects 20% of the population over 50 and significantly impairs mobility and ability to participate in activities of daily living (ADLs), as well as increases fall risk. It is commonly treated with costly surgery, at times with questionable efficacy. Injection therapy is challenging when the etiology is anatomical or compressive. Morton’s neuroma is a budging of the interdigital nerve. Steroid, alcohol, and capsaicin injections provide some benefit, but it is short lived. Hyaluronic acid (HA) injection provided long-term relief and could prove to be a viable treatment option. Achilles tendinopathy (AT) is most likely secondary to repeat tendon stress—platelet-rich-plasma (PRP) and prolotherapy have been trialed for this condition, but more evidence is required to show efficacy. Similar injections were trials for plantar fasciitis and achieved only short-term relief; however, some evidence suggests that PRP injections reduce the frequency of required therapy. Tarsal tunnel syndrome, a compressive neuropathy carries a risk of permanent neural injury if left untreated. Injection therapy can provide a bridge to surgery; however, surgical decompression remains the definitive therapy. When the etiology is inflammatory, steroid injection is more likely to provide benefit. This has been shown in several studies for gout, as well as osteoarthritis of the foot and ankle and treatment-refractory rheumatoid arthritis. HA showed similar benefit, possibly due to anti-inflammatory effects. Stem cell injections may provide the additional benefit of structure restoration.

Summary

Chronic foot pain is common in the general population and has significant associated morbidity and disability. Traditionally treated with surgery, these are costly and only somewhat effective. Injections provide an effective alternative financially and some evidence exists that they are effective in pain alleviation. However, current evidence is limited and the benefit described from injection therapy has been short-lived in most cases. Further studies in larger populations are required to evaluate the long-term effects of these treatments.

Delayed diagnosis of posterior ankle impingement in pediatric and adolescent patients: does radiology play a role?

BACKGROUND

Posterior ankle impingement syndrome (PAIS) results from the pinching of anatomical structures in the posterior part of the ankle.

OBJECTIVE

To identify the possible role of imaging in the delayed diagnosis of PAIS and identify key findings on imaging to suggest PAIS in pediatric and adolescent patients.

MATERIALS AND METHODS

Data were collected prospectively in patients younger than 18 years of age who underwent arthroscopy after being diagnosed with PAIS. Imaging was reviewed retrospectively by two radiologists, compared with findings in literature and an age-matched control group, and correlated with arthroscopic findings. Pre- and postsurgical Visual Analogue Scale (VAS) pain and American Orthopedic Foot Ankle Society (AOFAS) ankle-hindfoot scores were noted.

RESULTS

Thirty-eight patients (20 females, 18 males), 51 ankles, with an average age of 12.9 years had an average 18-month delay in diagnosis. Twenty-seven of the 38 (73%) patients had previously seen multiple medical providers and were given multiple misdiagnoses. Radiographs were reported normal in 34/47 (72%) ankles. Thirty patients had magnetic resonance imaging (MRI) and findings included the presence of an os trigonum/Stieda process (94%) with associated osseous edema (69%), flexor hallucis longus (FHL) tenosynovitis (16%), and edema in Kager's fat pad (63%). Although individual findings were noted, the impression in the MRI reports in 16/32 (50%) did not mention PAIS as the likely diagnosis. There was a significant difference in the MRI findings of ankle impingement in the patient population when compared to the control group. Surgery was indicated after conservative treatment failed. All 51 ankles had a PAIS diagnosis confirmed during arthroscopy. At an average follow-up of 10.2 months, there was improvement of VAS pain (7.0 to 1.1) and AOFAS ankle-hindfoot scores (65.1 to 93.5).

CONCLUSION

PAIS as a diagnosis is commonly delayed clinically in young patients with radiologic misinterpretation being a contributing factor. Increased awareness about this condition is needed among radiologists and physicians treating young athletes.

Posterior ankle impingement–an underdiagnosed cause of ankle pain in pediatric patients

BACKGROUND

Posterior ankle impingement syndrome (PAIS) is a cause of ankle pain due to pinching of bony or soft tissue structures in the hindfoot. The diagnosis is primarily made based on detailed history and accurate clinical examination. The delay in its diagnosis has not yet been described in the pediatric and adolescent population.

AIM

To identify and characterize misdiagnosed cases of PAIS in pediatric and adolescent patients.

METHODS

This descriptive prospective study at a tertiary children’s hospital included patients ≤ 18 years who underwent posterior ankle arthroscopy after presenting with chronic posterior ankle pain after being diagnosed with PAIS. Collected data included: Demographics, prior diagnoses and treatments, providers seen, time to diagnosis from presentation, and prior imaging obtained. Visual Analogue Scale (VAS) for pain and American Orthopedic Foot Ankle Society (AOFAS) ankle-hindfoot scores were noted at initial presentation and follow-up.

RESULTS

35 patients (46 ankles) with average age of 13 years had an average 19 mo (range 0-60 mo) delay in diagnosis from initial presentation. 25 (71%) patients had previously seen multiple medical providers and were given multiple other diagnoses. All 46 (100%) ankles had tenderness to palpation over the posterior ankle joint. Radiographs were reported normal in 31/42 (72%) exams. In 32 ankles who underwent MRI, the most common findings included os trigonum (47%)/Stieda process (47%). Conservative treatment had already been attempted in all patients. Ankle impingement pathology was confirmed during arthroscopy in 46 (100%) ankles. At an average follow-up of 13.1 mo, there was an improvement of VAS (pre-op 7.0 to post-op 1.2) and AOFAS scores (pre-op 65.1 to post-op 94).

CONCLUSION

This is the first study which shows that PAIS is a clinically misdiagnosed cause of posterior ankle pain in pediatric and adolescent population; an increased awareness about this diagnosis is needed amongst providers treating young patients.

Imaging the patient with heel pain

Heel pain is a common presentation in primary care and affects a wide range of the population but predominantly elderly, obese and athletic patients. History and clinical assessment are paramount in the management of this condition but the presentation can confound clinicians, necessitating the use of imaging to confirm or clarify the diagnosis when there is clinical uncertainty. This article illustrates the various conditions producing heel pain to help clinicians determine the appropriate imaging modality to image the common causes of heel pain. A linked article detailing the management of heel pain is included in this issue ( https://doi.org/10.12968/hmed.2019.80.4.196 ).

Accessory ossicles of the foot-an imaging conundrum

Various anatomical variations can be found in the foot and ankle, including sesamoid bones and accessory ossicles. These are usually incidental findings and remain asymptomatic; however, they may cause complications resulting in painful syndromes or degenerative changes secondary to overuse or trauma. They can also lead to fractures or simulate fractures. These complications are challenging to diagnose on radiographs. Advanced imaging with US, CT, MRI, or Tc-99m bone scan is useful for definitive diagnosis. This study aims to illustrate how imaging modalities can be used to diagnose complications of common sesamoids and accessory ossicles of the ankle and foot (hallux sesamoids, os trigonum, accessory navicular, os supranaviculare, os peroneum, os intermetatarseum, and os calcaneus secundarius) and demonstrate the imaging differences between fractures and their mimics.

Three-Dimensional Reconstruction of Foot in the Weightbearing Position From Biplanar Radiographs: Evaluation of Accuracy and Reliability

The initial assessment and postoperative monitoring of patients with various abnormalities of the foot in clinical routine practice is primarily based on the analysis of radiographs taken in the weightbearing position. Conventional x-ray imaging, however, only provides a 2-dimensional projection of 3-dimensional (3D) bony structures, and the clinical parameters assessed from these images can be affected by projection biases. In the present work, we addressed this issue by proposing an accurate 3D reconstruction method of the foot in the weightbearing position from low-dose biplanar radiographs with clinical index measurement assessment for clinical routine practice. The accuracy of the proposed reconstruction method was evaluated for both shape and clinical indexes by comparing 3D reconstructions of 6 cadaveric adult feet from computed tomographic images and from biplanar radiographs. For the reproducibility study, 3D reconstructions from the biplanar radiographs of the foot of 6 able-bodied subjects were considered, with 2 observers repeating each measurement of anatomic landmarks 3 times. Baseline assessment of important 3D clinical parameters was performed on 17 subjects (34 feet; mean age 27.7, range 20 to 52 years). The average point to surface distance between the 3D stereoradiographic reconstruction and the computed tomographic scan-based reconstruction was 1 mm (range 0mm to 6mm). The selected radiographic landmarks were highly reproducible (95% confidence interval <2.0 mm). The greatest interindividual variability for the clinical parameters was observed for the twisting angle (mean 87°, range 73° to 100°). Such an approach opens the way for routine 3D quantitative analysis of the foot in the weightbearing position.

Advanced MRI Techniques for the Ankle

OBJECTIVE

The purposes of this article are to present a state-of-the-art routine protocol for MRI of the ankle, to provide problem-solving tools based on specific clinical indications, and to introduce principles for the implementation of ultrashort echo time MRI of the ankle, including morphologic and quantitative assessment.

CONCLUSION

Ankle injury is common among both athletes and the general population, and MRI is the established noninvasive means of evaluation. The design of an ankle protocol depends on various factors. Higher magnetic field improves signal-to-noise ratio but increases metal artifact. Specialized imaging planes are useful but prolong acquisition times. MR neurography is useful, but metal reduction techniques are needed whenever a metal prosthesis is present. An ultrashort echo time sequence is a valuable tool for both structural and quantitative evaluation.