Stress fractures of the foot and ankle, part 2: site-specific etiology, imaging, and treatment, and differential diagnosis

Anatomy of the Naviculocuneiform Joint Complex

Background

The purpose of this study was to quantify the articular surfaces of the naviculocuneiform (NC) joint to help clinicians better understand common pathologies observed such as navicular stress fractures and arthrodesis nonunions.

Methods

Twenty cadaver NC joints were dissected and the articular cartilage of the navicular, medial, middle, and lateral cuneiforms were quantified by calibrated digital imaging software. Statistical analysis included calculating the mean cartilage surface area dimensions of the distal navicular and proximal cuneiform bones. Length measurements on the navicular were obtained to estimate the geographic location of the interfacet ridges. Lastly, all facets of the articular surfaces were described in regard to the shape and location of cartilaginous or fibrous components. Results were compared using Student t tests.

Results

Navicular cartilage was present over 75.4% of the surface area of the proximal NC joint, compared with 72.6% of combined cuneiform cartilage distally. The mean height of the deepest (dorsal-plantar) measurement of navicular articular cartilage was 18 ± 3 mm. The mean heights of the distal medial, middle, and lateral cuneiform articular facets were 15 ± 1 mm, 17 ± 2 mm, and 15 ± 2 mm, respectively.

Conclusion

There is significant variation among the articular surfaces of the NC joint. Additionally, the central third of the navicular was calculated to lie in the inter-facet ridge between the medial and middle articular facets of the navicular.

Clinical Relevance

Surgeons may consider this study data when performing joint preparation for NC arthrodesis as cartilage was present to a mean depth of 18 mm at the NC joint. Additionally, this study demonstrates that the central third of the navicular, where most navicular stress fractures occur, lies in the interfacet ridge between the medial and middle articular facets of the navicular.

The Heel Complex: Anatomy, Imaging, Pathologic Conditions, and Treatment

The differential diagnosis for heel pain is broad but primarily involves abnormalities of the Achilles tendon, calcaneus, and plantar fascia. Achilles tendon disorders include tendinosis, tendinitis, and partial or complete tears. Tendinosis refers to tendon degeneration, while tendinitis is inflammation after acute overload. Untreated tendinosis can progress to partial or complete tears. Tendon disorders can be accompanied by paratenonitis or inflammation of the loose sheath enclosing the tendon. Initial management involves rehabilitation and image-guided procedures. Operative management is reserved for tendon tears and includes direct repair, tendon transfer, and graft reconstruction. The calcaneus is the most commonly fractured tarsal bone. The majority of fractures are intra-articular; extra-articular fractures, stress or insufficiency fractures, medial process avulsion, and neuropathic avulsion can also occur. Posterosuperior calcaneal exostosis or Haglund deformity, retrocalcaneal bursitis, and insertional Achilles tendinosis form the characteristic triad of Haglund syndrome. It is initially managed with orthotics and physiotherapy. Operative management aims to correct osseous or soft-tissue derangements. The plantar fascia is a strong fibrous tissue that invests the sole of the foot and contributes to midfoot stability. Inflammation or plantar fasciitis is the most common cause of heel pain and can be related to overuse or mechanical causes. Acute rupture is less common but can occur in preexisting plantar fasciitis. Conservative treatment includes footwear modification, calf stretches, and percutaneous procedures. The main operative treatment is plantar fasciotomy. Plantar fibromatosis is a benign fibroblastic proliferation within the fascia that can be locally aggressive and is prone to recurrence. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

An assessment of the diagnosis, treatment, and outcomes of lower extremity stress fractures in pediatric and adolescent populations

OBJECTIVES

To present one of the first descriptive case series of pediatric and adolescent lower extremity stress injuries, their management, and outcomes in athletes and non-athletes.

METHODS

The IRB-approved retrospective study included patients under 18 years at a tertiary children's hospital who were diagnosed with a lower extremity stress fracture/reaction. Demographic data, mechanism of injury, physical exam, radiographic findings, treatment, & outcomes were collected. Descriptive statistical analysis was conducted.

RESULTS

Ninety-seven patients with stress injuries on clinical exams and on radiographs or MRI were included. The average age when diagnosed was 11.7 years (range 1.1-18 years) and the most common injuries were to the tibia (n = 33, 28.4%) and the least common involved were the cuneiforms (n = 4, 3.4%). Patients under the age of 14 were more likely to experience cuboid and calcaneal stress injuries (mean age 5.5 and 8.3 years respectively). Nineteen patients (19.6%) had high-risk stress fractures, with the average age of 14.9 years versus 11.6 for those with low risk (p-value = 0.01) and return to activity time being 15 weeks compared to 10.5 (p-value = 0.027). The most common forms of treatment were controlled ankle motion (CAM), walker boots (58.6%), and physical therapy (PT) (38.1%). The mean Lower Extremity Function Score of the patient population was 73.8, indicating no clinically important difference from full functionality.

CONCLUSION

Lower extremity stress injuries in this cohort were most seen in the tibia, although patients younger than 14 had a high number of cuboid and calcaneal stress injuries. Those with high-risk stress fractures were older and took longer to recover from when compared to low-risk injuries. Treatment is commonly conservative, with CAM boots and PT being the most frequently utilized interventions and serving as a successful approach to treatment, with patients returning to activity at an average of 11.4 weeks, which is comparable to similar studies.

[Stress fractures in the military context]

BACKGROUND

Soldiers, especially as recruits, are exposed to significantly elevated stress patterns of the foot due to occupation-related marching and excessive running. This can lead to military-specific stress fractures of the metatarsals, i.e., marching fractures. The treatment and prevention of stress fractures are of particular importance in the military context due to the impact on operational capability and treatment costs. A uniform classification of these fractures does not yet exist.

OBJECTIVE

Review of stress fractures in the military setting with presentation of the incidence, risk factors, classification, treatment and prevention possibilities.

MATERIAL AND METHODS

A PubMed®-based review of the current literature on stress fractures in the military context was conducted and the results were discussed with a focus on specific military medical treatment options.

RESULTS

There are several possibilities to classify stress fractures, the most well-known being a 4-level magnetic resonance imaging (MRI)-based classification. Prevention and treatment possibilities are multifaceted but so far insufficiently validated.

CONCLUSION

Military-specific stress fractures should be grouped according to a 4-level and MRI-based classification. The treatment options include both conservative and surgical measures and should be implemented taking the patient's individual requirements into account. Preventive measures play a key role in the military context. They include the adaptation of screening tools, training and equipment and require continuous evaluation and development.

[High-risk stress fractures in competitive athletes]

Bone stress injuries are chronic overload reactions of the bone, which are characterized by the load-dependent occurrence of locally perceived pain and tenderness on palpation at the site of the injury. Structurally normal bone becomes fatigued as a result of repetitive submaximal loading and/or inadequate regeneration. Certain stress fractures of the femoral neck (tension side), patella, anterior tibial cortex, medial malleolus, talus, tarsal navicular bone, proximal fifth metatarsal, and sesamoid bones of the great toe tend to develop complications (complete fractures, delayed union, pseudarthrosis, dislocation, arthrosis). These injuries are classified as high-risk stress fractures. Aggressive diagnostics and treatment are recommended when a high-risk stress fracture is suspected. Treatment is frequently different from low-risk stress fractures, including prolonged non-weight-bearing immobilization. In rare cases, surgery is indicated when conservative treatment fails, when a complete or non-healing fracture develops, or in cases of dislocation. The outcomes of both conservative and operative treatment are described as less successful compared with low-risk stress injuries.

[Contemporary imaging examinations for (suspected) stress fractures]

Stress fractures belong to the group of atraumatic fractures. A low-impact and repetitive load is the underlying cause and no fracture would occur under physiological circumstances. The conventional X‑ray examination remains the initial imaging modality when a stress fracture is suspected. In contrast, magnetic resonance imaging (MRI) is the gold standard and is also used to rule out other pathological changes. Computed tomography (CT) should be included if the MRI findings are unclear. New techniques, such as dual energy computed tomography (DECT) and magnetic resonance bone imaging (MR bone) should be used more frequently in practice in the future and become increasingly more important for the correct diagnosis.

High-resolution ultrasound and MRI in the evaluation of the forefoot and midfoot

Radiography is the appropriate initial imaging modality to assess for midfoot and forefoot pathology before turning to advanced imaging techniques. While most lesions of the mid- and forefoot can be diagnosed clinically, the exact nature and severity of the pathology is often unclear. This review addresses the use of the ultrasound, as well as the added value of magnetic resonance imaging, in diagnosing conditions of the midfoot and forefoot. Ultrasound allows a dynamic assessment as well as enabling imaging-guided interventions for diagnostic and therapeutic purposes. Practical tips for optimal examination of this area with ultrasound and magnetic resonance imaging are provided. Metatarsal stress fracture, Chopart's injury, Lisfranc injury, as well as the 1st metatarsophalangeal joint injury and lesser metatarsophalangeal plantar plate injury are injuries unique to the mid- and forefoot. The imaging anatomy of the 1st and lesser metatarsophalangeal joints is reviewed, as such knowledge is key to correctly assessing injury of these joints. Characteristic imaging features of masses commonly encountered in the mid- and forefoot, such as ganglion cyst, Morton neuroma, gouty tophus, plantar fibroma, foreign body granuloma, and leiomyoma are reviewed. The use of ultrasound and magnetic resonance imaging in assessing degenerative and inflammatory joint disorders, and in particular rheumatoid arthritis, of the mid- and forefoot region is also reviewed. In summary, when necessary, most lesions of the mid-and forefoot can be adequately assessed with ultrasound, supplemented on occasion with radiographs, computed tomography, or magnetic resonance imaging.

Weight-Bearing CT with Maximum Ankle Dorsiflexion to Identify Impingement and Tibial Plafond Stress Fracture: A Case Report

CASE

A 25-year-old male pole vaulter presented with several months of right ankle pain. Radiographs showed an anterior tibial osteophyte with a small intra-articular body suggesting impingement. Weight-bearing computed tomography (CT) revealed an associated tibial plafond stress fracture. Subsequent arthroscopy with osteophyte resection and loose body removal significantly improved symptoms, and he gradually resumed training.

CONCLUSION

Stress fractures should always be considered in athletes with ankle pain. A unique aspect of this case was the use of weight-bearing CT in diagnosis and surgical planning. To our knowledge, this is the first described case in which weight-bearing CT was used in this fashion.

MRI of Pediatric Foot and Ankle Conditions

The increase in competitive sports practice among children and lack of ionizing radiation have resulted in a higher demand for MRI examinations. MRI of the children skeleton has some particularities that can lead orthopedists, pediatricians, and radiologists to diagnostic errors. The foot and ankle have several bones with abundant radiolucent and high signal intensity cartilage in several ossification centers, apophysis and physis, that can make this interpretation even harder. The present revision aims to show, how to differentiate between normal developmental findings and anatomic variants from pathologic conditions, whether mechanical, inflammatory, infectious, or neoplastic.

Republication of "Stress Fractures of the Foot and Ankle in Athletes"

Stress fractures of the foot and ankle are common injuries in athletes. Management differs considerably based on fracture location and predisposing factors. Repetitive loading of the foot and ankle in athletes should result in physiologic bone remodeling in accordance with Wolff's law. However, when there is not sufficient time for complete healing to occur before additional loads are incurred, this process can instead lead to stress fracture. Assessment of the athlete's training regimen and overall bone health is paramount to both the discovery and treatment of these injuries, although diagnosis is often delayed in the setting of normal-appearing initial radiographs. While most stress fractures of the foot or ankle can usually be treated nonoperatively with a period of activity modification, fractures in certain locations are considered "high risk" due to poor intrinsic healing and may warrant more proactive operative management.

Bone Stress Injuries at the Ankle and Foot

Bone stress injuries (BSIs) are a frequent finding in athletes, particularly of the foot and ankle. A BSI is caused by recurring microtrauma to the cortical or trabecular bone exceeding the repair capacity of normal bone. The most frequent fractures at the ankle are low risk, characterized by a low risk for nonunion. These include the posteromedial tibia, the calcaneus, and the metatarsal diaphysis. High-risk stress fractures have a higher risk for nonunion and need more aggressive treatment. Examples are the medial malleolus, navicular bone, and the base of the second and fifth metatarsal bone.Imaging features depend on the primary involvement of cortical versus trabecular bone. Conventional radiographs may remain normal up to 2 to 3 weeks. For cortical bone, early signs of BSIs are a periosteal reaction or the "gray cortex sign," followed by cortical thickening and fracture line depiction. In trabecular bone, a sclerotic dense line may be seen. Magnetic resonance imaging enables early detection of BSIs and can differentiate between a stress reaction and a fracture. We review typical anamnestic/clinical findings, epidemiology and risk factors, imaging characteristics, and findings at typical locations of BSIs at the foot and ankle that may help guide treatment strategy and patient recovery.

Imaging of Overuse Injuries of the Ankle and Foot in Sport and Work

Overuse injuries of the ankle and foot are common injuries both in sport and in a work-related context. After clinical assessment, imaging is key for early diagnosis. In this overview article, we focus on imaging techniques, protocols, and imaging findings of overuse injuries of the ankle and foot; we emphasize the important role of structured reporting; and we discuss clinical symptoms, epidemiology, and risk factors in sports and in a work-related context.

Bone Marrow Lesions in Athletic Stress Injuries: An Overview

This article discusses the presumed pathophysiology of osseous sport-related stress changes, the optimal imaging strategy for detecting the lesions, and the progression of the lesions as seen on magnetic resonance imaging. It also describes some of the most common stress-related injuries in athletes by anatomical location and introduces some new concepts in the field.

Radiological outcomes of bimalleolar fractures: Are timing of surgery and type of reconstruction important?

OBJECTIVE

The goal of open reduction and internal fixation (ORIF) of bimalleolar ankle fractures is to reconstitute ankle anatomy. The most commonly used radiological parameters to assess adequacy of reduction are talocrural angle (TCA), medial clear space (MCS), tibiofibular overlap (TFO) and tibiofibular clear space (TFCS). There is little research about the radiological outcomes of surgery in bimalleolar fractures. We aimed at assessing the adequacy of ORIF and the factors involved in anatomical restoration (specifically time to surgery), postoperatively and at follow-up.

METHODS

TCA, MCS, TFO and TFCS were measured in preoperative and postoperative radiographs of 107 bimalleolar ankle fractures and in 83 follow-up radiographs, accounting for a total of 297 radiographs and 1182 measurements. Preoperative radiographs were categorized according to Danis-Weber classification. For all included cases, basic demographic data, dates of radiographs and surgery, and type of fixation used were acquired. Variables associated with postoperative and follow-up total anatomical reconstitution (i.e., when the four assessed radiological parameters were normalized), normalization of each radiological parameter, and improvement in the number of normalized radiological parameters were identified through univariable Cox regression analysis.

RESULTS

In our sample, 23.8% of the ankle fractures in postoperative radiographs and 28% in follow-up radiographs achieved a complete anatomical restoration. Type C fractures (hazard ratio [HR]=0.1, 95% confidence interval [CI]=0.02-0.7, P=0.021) were associated with lower chances of total anatomical reconstitution. The use of reconstruction plates (HR=0.1, 95% CI=0.03-0.7, P=0.014) and one third tubular plates (HR=0.2, 95% CI=0.03-0.8, P=0.026) decreased the chances of improving the number of normalized radiological parameters. Waiting days until surgery impaired total anatomical reconstitution (HR=0.8, 95% CI=0.6-0.9, P=0.012) and also reduced the chances of improving the number of normalized radiological parameters (HR=0.9, 95% CI=0.9-1.0, P=0.045).

CONCLUSION

The radiological results for the treatment of bimalleolar fractures are time sensitive, and surgery should thus be performed as soon as possible, using adequate fixation materials, in order to achieve a better restoration of ankle anatomy.

LEVEL OF EVIDENCE

IV, retrospective study.

Lower-extremity fatigue fracture detection and grading based on deep learning models of radiographs

OBJECTIVES

To identify the feasibility of deep learning-based diagnostic models for detecting and assessing lower-extremity fatigue fracture severity on plain radiographs.

METHODS

This retrospective study enrolled 1151 X-ray images (tibiofibula/foot: 682/469) of fatigue fractures and 2842 X-ray images (tibiofibula/foot: 2000/842) without abnormal presentations from two clinical centers. After labeling the lesions, images in a center (tibiofibula/foot: 2539/1180) were allocated at 7:1:2 for model construction, and the remaining images from another center (tibiofibula/foot: 143/131) for external validation. A ResNet-50 and a triplet branch network were adopted to construct diagnostic models for detecting and grading. The performances of detection models were evaluated with sensitivity, specificity, and area under the receiver operating characteristic curve (AUC), while grading models were evaluated with accuracy by confusion matrix. Visual estimations by radiologists were performed for comparisons with models.

RESULTS

For the detection model on tibiofibula, a sensitivity of 95.4%/85.5%, a specificity of 80.1%/77.0%, and an AUC of 0.965/0.877 were achieved in the internal testing/external validation set. The detection model on foot reached a sensitivity of 96.4%/90.8%, a specificity of 76.0%/66.7%, and an AUC of 0.947/0.911. The detection models showed superior performance to the junior radiologist, comparable to the intermediate or senior radiologist. The overall accuracy of the diagnostic model was 78.5%/62.9% for tibiofibula and 74.7%/61.1% for foot in the internal testing/external validation set.

CONCLUSIONS

The deep learning-based models could be applied to the radiological diagnosis of plain radiographs for assisting in the detection and grading of fatigue fractures on tibiofibula and foot.

KEY POINTS

• Fatigue fractures on radiographs are relatively difficult to detect, and apt to be misdiagnosed. • Detection and grading models based on deep learning were constructed on a large cohort of radiographs with lower-extremity fatigue fractures. • The detection model with high sensitivity would help to reduce the misdiagnosis of lower-extremity fatigue fractures.

The painful lateral column of the foot: from back to front

The purpose of this article is to focus attention on the abnormalities which the radiologist may encounter in patients presenting with lateral ankle or foot pain outside of the context of acute trauma. These include anterolateral impingement, subfibular impingement, subtalar instability and tarsal sinus syndrome, tarsal coalition, sural neuromas, peroneal tendon abnormalities, calcaneocuboid instability and occult cuboid fractures, and painful accessory ossicles. The expected and unexpected findings on radiographs, CT, US, and MRI are discussed.

The Effectiveness of Intramedullary Screw Fixation Using the Herbert Screw for Fifth Metatarsal Stress Fractures in High-Level Athletes

BACKGROUND

Intramedullary screw fixation is the most common operative procedure used for treatment of fifth metatarsal stress fractures in athletes. However, the optimal implant in intramedullary screw fixation is still being investigated.

PURPOSE

To review experiences with intramedullary screw fixation using the Herbert screw for fifth metatarsal stress fractures in high-level athletes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The authors retrospectively analyzed 37 high-level athletes (Tegner activity score ≥7) who underwent intramedullary screw fixation using the Herbert screw for fifth metatarsal stress fractures between August 2005 and August 2017. The minimum follow-up period of the patients was 2 years. In assessing the surgical results, time to obtain bone union, time to return to original level of sport participation, and treatment failures/complications were reviewed. Additionally, the effect of intraoperative plantar gap widening caused by the screw insertion was analyzed. The surgical results of the 2 groups, the no-gap group (intraoperative plantar gap widening, <1 mm) and the gap group (intraoperative plantar gap widening, ≥1 mm), were compared, while correlations between intraoperative plantar gap widening and the surgical results were statistically analyzed.

RESULTS

Bone union and return to the original sport were attained in all patients without treatment failures/complications such as delayed union, nonunion, or refracture. The mean time to obtain bone union was 10.1 weeks, and the mean time to return to sport was 10.9 weeks. In comparing the no-gap group (n = 16) and the gap group (n = 21), no significant differences in the time to obtain bone union (P = .392) or to return to sport (P = .399) were noted. Additionally, there was no correlation between intraoperative plantar gap widening and the time to obtain bone union (r = 0.131; P = .428) or to return to sport (r = 0.160; P = .331).

CONCLUSION

The use of the Herbert screw for intramedullary screw fixation to treat fifth metatarsal stress fractures in high-level athletes provided satisfactory results enabling all the athletes to return to the original sport without treatment failures/complications. Additionally, intraoperative plantar gap widening does not affect the surgical results using this technique.

Stress Imaging of Bone

This article defines stress injury, including insufficiency and fatigue fractures. The pathophysiology and risk factors for development of stress injuries are also discussed. The most common locations, including specific imaging examples, are reviewed with an emphasis on early detection and differentiation of high-risk and low-risk locations. Optimal imaging modalities with associated imaging findings are covered, as well as some potential pitfalls to avoid. The importance of correlating imaging findings with symptoms and the prognostic value of imaging grading are also discussed.

[Stress fractures of the lower limbs]

Stress reactions and fractures represent an important differential diagnostic entity, especially in patients active in sports. The lower extremities have predilection sites for stress fractures, which require special treatment in the context of the underlying risk factors. Clinically, patients usually complain of stress-dependent pain in the affected region and sport activities are mostly limited or even impossible. The detection of acute stress fractures is usually missed by conventional X‑ray within the first 4-6 weeks. The gold standard diagnostic tool is magnetic resonance imaging (MRI). Depending on the location, a distinction must be made between low-risk and high-risk stress fractures. Low-risk fractures show a high healing rate after conservative treatment including load and stress reduction as well as avoiding risk factors. High-risk fractures can take a complicated course under conservative treatment measures and in some cases, surgical intervention is required.

Navicular Stress Fractures

Navicular stress fractures are multifactorial injuries due to chronic overload on the navicular, particularly in young athletes. The navicular is subject to unique stresses and has a complex blood supply, making it susceptible to stress fractures and potentially delayed union or nonunion. Expeditious diagnosis is critical to prevent a delay in treatment and a poor outcome. Advanced imaging is essential in making the diagnosis and monitoring healing. Both nonsurgical and surgical treatments have demonstrated good results. Nonsurgical management consists of a period of immobilization and nonweight bearing, and surgical management typically involves open reduction and internal fixation. Patients need to be appropriately counseled regarding expectations for these challenging injuries.

Magnetic resonance imaging of the ankle and foot

This article reviews the magnetic resonance imaging (MRI) findings of the normal anatomy and various pathologic conditions of the ankle and foot commonly encountered in clinical practice. The spectrum of entities discussed includes osseous and osteochondral injuries, ligamentous injuries, common traumatic and degenerative tendon pathology, abnormalities of transverse tarsal joint (Chopart) and tarsometatarsal joint (Lisfranc) complexes, pathological conditions affecting capsuloligamentous structures of the great toe and lesser toes, as well as pedal infection, with a focus on diabetic osteomyelitis and neuropathic osteoarthropathy.

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.

Geometric and "True" Densitometric Characteristics of Bones in Athletes with Stress Fracture and Menstrual Disturbances: A Systematic Review

BACKGROUND

Stress fractures can lead to short- and long-term consequences, impacting participation in sport and general health. Recognizing which skeletal characteristics render bones susceptible to stress fracture may aid stress-fracture prevention. Menstrual disturbances among exercising women are a known risk factor for stress fracture; therefore, assessing skeletal commonalities between women with stress fractures and women with menstrual disturbances may increase our understanding of why menstrual disturbances put athletes at greater risk for stress fracture. Three-dimensional (3D) bone imaging tools provide detailed information about volumetric bone mineral density (vBMD) and bone structure that cannot be obtained using traditional two-dimensional (2D) techniques.

OBJECTIVES

This systematic review serves to: (1) evaluate the current literature available on vBMD, bone geometry, and bone structure in exercising women with menstrual disturbances and exercising women with stress fractures, and (2) assess the common skeletal characteristics between both conditions. Our aim is to reveal bone properties beyond 2D areal BMD that may indicate increased susceptibility to stress fracture among exercising women with menstrual disturbances.

SEARCH METHODS

A search of the PubMed/Medline database was completed in May 2018.

ELIGIBILITY CRITERIA

Eligible articles included those that reported vBMD, bone geometry, or bone structure obtained from 3D imaging techniques or estimated from 2D imaging techniques. Only studies conducted in premenopausal exercising women and girls who had a stress fracture, a menstrual disturbance, or both were included.

RESULTS

Twenty-four articles met the inclusion criteria. Bone area and cortical thickness at the tibia were identified as altered both in women with menstrual disturbances and in women with stress fractures; however, there was inconsistency in the results observed for all bone parameters. The majority of skeletal parameters of the lower extremities were not significantly different between exercising women with and without stress fractures and between those with and without menstrual disturbances.

DISCUSSION

Most studies were moderate or low quality based on study design, and only one article combined both conditions to explore vBMD and bone geometry in athletes with menstrual disturbances and a history of stress fracture. These findings highlight the need for more skeletal research on the intersection of these health conditions in exercising women. The lack of observed differences in skeletal parameters suggests that risk factors other than bone geometry and structure may be the primary causes of stress fracture in these women.

Tibial bone stress injury: diagnostic performance and inter-reader agreement of an abbreviated 5-min magnetic resonance protocol

OBJECTIVE

To compare the diagnostic performance and inter-reader agreement of an abbreviated (5 min) MR protocol compared to a complete (25 min) protocol, for evaluation of suspected tibial bone stress injury.

MATERIALS AND METHODS

This IRB-approved retrospective study consisted of 95 consecutive MR examinations in 88 patients with suspected tibial bone stress injury. Three musculoskeletal radiologists independently classified all examinations utilizing both an abbreviated protocol consisting only of axial T2-weighted images with fat suppression, and after a washout period again classified the complete examinations. Accuracy was calculated as proportion of cases classified exactly, within 1 grade, within 2 grades, and also utilizing a simplified "clinically relevant" classification combining grades 2, 3, and 4A into a single group. Significance testing was performed with the chi-test, and a post-hoc power analysis was performed. Inter-reader agreement was calculated with Kendall's coefficient of concordance, with significance testing performed utilizing the z-test after bootstrapping to obtain the standard error.

RESULTS AND CONCLUSIONS

There was no significant difference in accuracy of grading tibial bone stress injuries between complete and abbreviated examinations. For complete exams, pooled exact accuracy was 47.8%; accuracy within 1 grade was 82.8%; and accuracy within 2 grades was 96.1%. For the abbreviated protocol, corresponding accuracies were 50.2, 82.0, and 93.9%. With the "clinically relevant" simplified classification, accuracy was 58.6% for complete exams and 64.2% for abbreviated exams. There was no significant difference in inter-reader agreement, with substantial agreement demonstrated for both complete (Kendall coefficient of concordance 0.805) and abbreviated examinations (coefficient of 0.767).

Calcaneal insufficiency fractures following total knee arthroplasty: Classification and clinical findings

BACKGROUND

Calcaneal insufficiency fracture (IF) following total knee arthroplasty (TKA) is a rare disorder. This study aimed to examine the prevalence and clinical findings of calcaneal IF following TKA.

METHODS

We retrospectively reviewed 3,585 consecutive patients undergoing primary TKA between 2012 and 2017 in four hospitals. Calcaneal IF following TKA was diagnosed by plain radiography or magnetic resonance imaging. First, we investigated the prevalence and clinical findings of calcaneal IF following TKA. Second, we classified calcaneal IF into three types based on its location: type 1, fracture by traction force around the Achilles tendon insertion; type 2, compression fracture around the posterior subtalar joint; and type 3, fracture by ground reaction force at the bottom of the calcaneus. Finally, we compared the clinical findings between calcaneal IF with and without TKA.

RESULTS

Calcaneal IF following TKA was seen in 17 (0.5%) of the 3,585 patients undergoing primary TKA. All patients were female, with a mean age of 76.5 ± 5.9 years, relatively high body mass index (BMI), and osteoporosis. All fractures achieved bone union with conservative treatment. Type 1 fractures were the most common. Calcaneal IFs following TKA were significantly shorter in height and the patients had higher BMI than those without TKA. The locations of calcaneal IF following TKA varied, while only type 1 calcaneal IFs were seen in cases without TKA. However, there were no significant differences with regard to the bone union period or malunion between the two groups.

CONCLUSIONS

Calcaneal IF should be suspected in patients presenting with ipsilateral foot pain following TKA, particularly in female patients with a relatively high BMI and osteoporosis. Calcaneal IF can be classified into three types based on the fracture location. These variations in calcaneal IF may be due to differences in conditions and changes in mechanical loading of the lower extremity and bone quality following TKA.

Hallux sesamoid fractures in young athletes

Objective: To describe the evaluation, management and recovery time of hallux sesamoid fractures in young athletes.Methods: A retrospective chart review was performed in a large academic teaching institution over a 5-year period (1/1/2010-12/31/2014). All patients with a sesamoid injury were initially included. Excluded were those patients who: 1) did not receive the diagnosis of hallux sesamoid fracture, had a history of prior foot surgery, or had medical records inadequate for analysis, 2) had missing or unclear diagnostic imaging, 3) were age >21 years, or 4) did not report sports participation. Descriptive statistics were employed to analyze the data.Results: Fifty-eight patients (51 females and 7 males) with a mean age of 15.4 years (range: 9-21) were identified with a total of 59 sesamoid fractures. Dancing (37.9%), running (13.8%), and gymnastics (13.8%) were the most common sports reported among these patients. A greater number of fractures were classified as repetitive stress injuries (83.1%), rather than acute traumatic injuries (16.9%). Fractures were treated conservatively in the majority of cases (89.8%), and only six fractures (10.2%) were treated surgically. Most patients (84.7%) were able to return to sports and activities. The average time from diagnosis/start of treatment to pain-free state/cleared to return to sport was 161.4 days.Conclusion: Diagnosis of sesamoid fractures can be challenging, but overall most patients do well with conservative treatment and are able to return to sports and activities. Providers should keep sesamoid fracture in the differential when evaluating patients with pain in the area around the base of the first toe, especially in dancers, gymnasts, and runners. Understanding that the recovery from a sesamoid fracture can be a prolonged process may help patients develop realistic expectations.

[Stress fracture of athletes as a cause of groin pain]

CLINICAL/METHODICAL ISSUE

In this article, suitable imaging of stress reactions and stress fractures in athletes will be examined.

STANDARD RADIOLOGICAL METHODS

Diagnostic procedures include X‑ray, computed tomography (CT), magnetic resonance imaging (MRI), and bone scintigraphy.

METHODICAL INNOVATIONS

MRI represents the gold standard for these types of injuries.

PERFORMANCE

Of all imaging techniques, MRI shows the highest sensitivity in terms of diagnostic and prognostic aspects in stress reactions and stress fractures.

PRACTICAL RECOMMENDATIONS

Early performance of MRI to evaluate the staging, therapy and prognosis of the healing process is recommended.

[Metatarsal and toe fractures]

Metatarsal and toe fractures are the most frequent injuries of the foot skeleton. Nondislocated fractures can be conservatively treated with good success. Long-term relief and immobilization including the ankle joint are unnecessary. Metatarsal fractures close to the base are nearly always associated with Lisfranc luxation and treatment must also take the instability of the tarsometatarsal joints into consideratíon. Basal fractures of the 5th metatarsal bone require a differentiated consideration. The correct classification is necessary in order to initiate an adequate treatment. In general, intra-articular layer formation, inclination >10° and shortening between 3 mm and 5 mm, taking the position of the head of the metatarsal bone into consideration, are recommended as indications for surgery. Operative treatment of toe fractures is only rarely necessary.

Is Use of Bone Cement for Treatment of Second Metatarsal Stress Fractures Safe? A Case Report

Metatarsal stress fractures are common injuries of the foot and can be a source of chronic pain without appropriate management. Conservative management is first line, but surgery may be indicated in athletes, cases of nonunion, and fractures of the fifth metatarsal. We report a case of a 34-year-old female who presented to clinic for intractable pain of the left foot secondary to a stress fracture of the left second metatarsal, which had been previously treated with injectable acrylic bone cement. Calcium sulfate hydroxyapatite cement has a multitude of applications in orthopedic surgery, but to our knowledge no studies have documented its use in the treatment of metatarsal stress fractures. Our findings suggest that injectable calcium sulfate hydroxyapatite cement is not a suitable stand-alone treatment in fractures of the second metatarsal.

Bilateral Stress Fractures of the Talus Associated with Adult-Acquired Flatfoot Deformities

Adult-acquired flatfoot deformity is a progressive flattening of the arch of the foot that results from posterior tibial tendon insufficiency with a predilection for middle-aged women. A lateralized force vector associated with hindfoot valgus in adult-acquired flatfoot produces lateral ankle pain due to impingement at the lateral hindfoot, which can even lead to stress fractures of the distal fibula. Here, we present the rare case of a 73-year-old woman who presented with stress fractures of the bilateral taluses and unilateral distal fibula accompanied by severe adult-acquired flatfoot deformities.

Regulatory role of microRNA-185 in the recovery process after ankle fracture

The present study aimed to investigate the expression of microRNA (miR)-185 in the bone and blood tissues following ankle fracture, and its regulatory mechanism in the ankle fracture recovery process. In total, 28 patients with ankle fractures were included, including 15 cases receiving surgical treatment within 1-7 days after fracture, and 13 cases receiving surgery within 8-14 days after fracture. Reverse transcription-quantitative polymerase chain reaction was performed to detect the mRNA expression levels. Western blot analysis and ELISA were used to determine the protein expression levels. Bioinformatics analysis and dual-luciferase reporter assay were applied to predict and confirm the upstream regulator of tumor growth factor (TGF)-β1. An MTT assay was performed to assess the cell proliferation. Compared with the 1-7-day surgery group, the mRNA and protein expression levels of TGF-β1 were significantly elevated, while the expression levels of miR-185 were significantly declined in the bone and blood tissues in the 8-14-day surgery group. Bioinformatics analysis and dual-luciferase reporter assay predicted and confirmed that TGF-β1 was the direct target gene of miR-185. Moreover, upregulated expression of miR-185 significantly decreased the protein expression levels of TGF-β1 and reduced the proliferating activity of hFOB1.19 cells. Within two weeks after ankle fracture, the expression levels of TGF-β1 are significantly upregulated in the bone and blood tissues, which may have been associated with the downregulated expression of miR-185. miR-185 may modulate TGF-β1 to regulate the recovery of ankle fracture. These findings may contribute to the understanding of the biological functions and effects of miRNA-185 and TGF-β1 in ankle fractures.

Stress Fractures of the Foot and Ankle in Athletes

Stress fractures of the foot and ankle are common injuries in athletes. Management differs considerably based on fracture location and predisposing factors. Repetitive loading of the foot and ankle in athletes should result in physiologic bone remodeling in accordance with Wolff’s law. However, when there is not sufficient time for complete healing to occur before additional loads are incurred, this process can instead lead to stress fracture. Assessment of the athlete’s training regimen and overall bone health is paramount to both the discovery and treatment of these injuries, although diagnosis is often delayed in the setting of normal-appearing initial radiographs. While most stress fractures of the foot or ankle can usually be treated nonoperatively with a period of activity modification, fractures in certain locations are considered “high risk” due to poor intrinsic healing and may warrant more proactive operative management.

Calcaneal fractures: radiological and CT evaluation and classification systems

Background and aim of the work: The calcaneus, the more lower bone of the body, has the task of supporting the axial load from the weight of the body. Calcaneal fractures represent about 1-2% of all fractures and 60% of the tarsal bones fractures. The articular involvement has been associated with a poor functional outcome. The aim of this work is to describe the radiologic evaluation, the classification systems, the morphological preoperative diagnostic imaging features of calcaneal fractures, highlighting the correlation with the choice of treatment and predictive capacity for the fracture surgical outcome. Methods: A PubMed search was performed for the terms Imaging calcaneus fracture, selecting articles in English language, published in the last two years, where preoperatively diagnostic imaging of fractures of the calcaneus are described. Case reports have not been included. Results: We have collected a number of data that provide important help in preoperative evaluation of calcaneal fractures, such as the new classification system created by Harnroongroj et al, the association of calcaneal fractures with fractures of other bone structures or soft tissue impairment, the use of calcaneotalar ratio in assessing the length of heel. Conclusions: These data suggest an approach geared to the specific choice of treatment and to improving patient outcomes. (www.actabiomedica.it)