Improving Diagnostic Accuracy and Efficiency of Suspected Bone Stress Injuries

Biologic therapies in stress fractures: Current concepts

Stress fractures, a common overuse injury in physically active individuals, present a significant challenge for athletes and military personnel. Patients who sustain stress fractures have demanding training regimes where periods of rest and immobilisation have unacceptable negative consequences on sports goals and finances. Aside from being an overuse injury, there are various contributing risk factors that put certain individuals at risk of a stress fracture. The main two being nutritional deficiencies and hormonal variations, which have significant effects on bone metabolism and turnover. Historically, treatment of stress fractures focused on conservative strategies such as rest and immobilisation. Calcium and vitamin D deficiencies have been closely linked to stress fractures and so over time supplementation has also played a role in treatment. With the introduction of biologics into orthopaedics, newer treatment strategies have been applied to accelerate fracture healing and perhaps improve fracture callus quality. If such therapies can reduce time spent away from sport and activity, it would be ideal for treating stress fractures. This article aims to offer insights into the evolving landscape of stress fracture management. It investigates the pre-clinical evidence and available published clinical applications. Though fracture healing is well understood, the role of biologics for fracture healing is still indeterminate. Available literature for the use of biologic therapies in stress fractures are restricted and most reports have used biologics as a supplement to surgical fixation in subjects in studies that lack control groups. Randomised control trials have been proposed and registered by a few groups, with results awaited. Assessing individuals for risk factors, addressing hormonal imbalances and nutritional deficiencies seems like an effective approach to addressing the burden of stress fractures. We await better designed trials and studies to accurately determine the clinical benefit of adding biologics to the management of these injuries.

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.

Prospective Assessment of Clinical Tests Used to Evaluate Tibial Stress Fracture

Background:

Tibial stress fracture (SFx) is the most common SFx of the lower extremity. Presently, diagnostic accuracy of clinical examination techniques for tibial SFx remains suboptimal.

Purpose:

To assess the diagnostic effectiveness of 5 clinical tests for tibial SFx individually versus a test item cluster.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

A total of 50 patients with tibial pain (17 with bilateral symptoms) were assessed with 5 clinical examination tests (tibial fulcrum test, focal tenderness to palpation, heel percussion test, therapeutic ultrasound test, and 128-Hz tuning fork test) before they underwent diagnostic imaging (radionuclide bone scan). The application of the clinical tests was counterbalanced to minimize the likelihood of carryover effects. Patients provided a pain rating immediately before and after the application of each clinical test.

Results:

The prevalence of tibial SFx among the study participants was 52.2%. High levels of specificity were produced by the therapeutic ultrasound test (93.8%), tuning fork test (90.6%), and percussion test (90.6%). The fulcrum test had moderate to high specificity (84.4%). All tests demonstrated low levels of sensitivity, with the highest levels found for focal tenderness to palpation (48.6%) and fulcrum (45.7%). The fulcrum test provided the highest positive likelihood ratio (2.93), followed by the therapeutic ultrasound test (2.30). The fulcrum test had the lowest negative likelihood ratio (0.64), with the focal tenderness to palpation and tuning fork tests having negative likelihood ratios >1.0. Combinations of these clinical tests did not improve the prediction of tibial SFx above that observed among the individual tests.

Conclusion:

The clinical tests evaluated were generally highly specific, but all had low sensitivity. The fulcrum test provided the highest level of diagnostic accuracy; however, it was inadequate for definitive clinical management. Combining tests did not improve the diagnostic accuracy of tibial SFx.

Sacral stress fractures in athletes

PURPOSE

Fatigue stress fractures are a common overuse injury, frequently associated with high load-bearing endurance activities such as running, military training and aerobic exercise. While these fractures can arise at any site, sacral stress fractures are poorly studied with evidence consisting mainly of case reports and limited case series. This review aims to analyze and summarize all reports published to date describing cases of sacral stress fracture in athletes.

METHODS

PubMed, Embase, Web of Science and the Cochrane Database were systematically searched for studies reporting on Stress Fractures of the Sacrum. Insufficiency fractures of the elderly were excluded.

RESULTS

The literature review revealed 49 studies reporting on 124 cases of sacral stress fractures. Seventy-six patients (61%) were professional or collegiate level athletes, and 37 (30%) were military recruits or police officers in training. Seventeen female athletes were identified as suffering from low bone mineral density (25%), 9 of which reported menstrual irregularities. Thirteen female patients (19%) had a history of eating disorders.

CONCLUSION

While most sacral stress fractures occur in normal bones exposed to abnormal repetitive loads, the high percentage of lower bone mineral density can blur the lines between fatigue fractures and insufficiency fractures. The causes of these fractures are multifactorial. High endurance sports and the features of the female athlete triad were found in high percentage of the cases. Conservative treatment is the mainstay of treatment, consisting of ceasing of training and a period of rehabilitation and gradual return to training and competition.

Overuse-Related Injuries of the Musculoskeletal System: Systematic Review and Quantitative Synthesis of Injuries, Locations, Risk Factors and Assessment Techniques

Overuse-related musculoskeletal injuries mostly affect athletes, especially if involved in preseason conditioning, and military populations; they may also occur, however, when pathological or biological conditions render the musculoskeletal system inadequate to cope with a mechanical load, even if moderate. Within the MOVIDA (Motor function and Vitamin D: toolkit for risk Assessment and prediction) Project, funded by the Italian Ministry of Defence, a systematic review of the literature was conducted to support the development of a transportable toolkit (instrumentation, protocols and reference/risk thresholds) to help characterize the risk of overuse-related musculoskeletal injury. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach was used to analyze Review papers indexed in PubMed and published in the period 2010 to 2020. The search focused on stress (overuse) fracture or injuries, and muscle fatigue in the lower limbs in association with functional (biomechanical) or biological biomarkers. A total of 225 Review papers were retrieved: 115 were found eligible for full text analysis and led to another 141 research papers derived from a second-level search. A total of 183 papers were finally chosen for analysis: 74 were classified as introductory to the topics, 109 were analyzed in depth. Qualitative and, wherever possible, quantitative syntheses were carried out with respect to the literature review process and quality, injury epidemiology (type and location of injuries, and investigated populations), risk factors, assessment techniques and assessment protocols.

Outcomes of Embedded Athletic Training Services Within United States Air Force Basic Military Training

CONTEXT

Musculoskeletal injury is the leading cause of attrition from military training.

OBJECTIVE

To assess the effect of an embedded athletic training musculoskeletal care model within a basic military training unit.

DESIGN

Cluster randomized trial.

SETTING

United States Air Force Basic Military Training, Joint Base San Antonio-Lackland.

PATIENTS OR OTHER PARTICIPANTS

Military recruits randomly assigned to 1 of 3 training squadrons, 2 control and 1 experimental, between January 2016 and December 2018.

INTERVENTION(S)

A sports medicine care model was established in 1 squadron by embedding 2 certified athletic trainers overseen by a sports medicine fellowship-trained physician. The athletic trainers diagnosed and coordinated rehabilitation as the primary point of contact for recruits and developed interventions with medical and military leadership based on injury trends.

MAIN OUTCOME MEASURE(S)

Recruit attrition from basic training due to a musculoskeletal injury. Secondary outcomes were all-cause attrition, on-time graduation, rates of lower extremity injury and stress fracture, rates of specialty care appointments, and fiscal costs.

RESULTS

Recruits in the athletic training musculoskeletal care arm experienced 25% lower musculoskeletal-related attrition (risk ratio = 0.75 [95% confidence interval (CI) = 0.64, 0.89]) and 15% lower all-cause attrition (risk ratio = 0.85 [95% CI = 0.80, 0.91]), translating to a net saving of more than $10 million. The intervention reduced the incidence of lower extremity stress fracture by 16% (rate ratio = 0.84 [95% CI = 0.73, 0.97]).

CONCLUSIONS

An embedded athletic training musculoskeletal care model outperformed usual care across operational, medical, and fiscal outcomes.

Overstride-Induced Medial Knee Desmopathy: An Exploration Case Series

Nine runners with varied experience but similar running-gait forms presented with the insidious and progressive onset of medial knee pain. Functional tightness of the semimembranosus (SM) tendon appeared to be a concomitant factor in the pain presentation of these patients. When evaluating atraumatic medial knee pain in runners, clinicians must consider bone stress injuries and atypical conditions. A functionally tight SM may induce pain and desmopathy of the medial collateral ligament through direct fiber entanglement or cause entrapment of infrapatellar branches of the saphenous nerve or both. Relieving SM tension resulted in short-term pain reduction while eliminating the overstride during the running gait over the long term appeared to prevent recurrence.

Stress fractures in uncommon location: Six case reports and review of the literature

BACKGROUND

Individuals' interest in sports activities has been increasing, contributing to more stress fracture occurrences in uncommon locations on the skeleton. In this study, several cases of stress fractures in atypical locations are presented, and the possibility of combining diagnostic methods to make accurate and quick diagnoses is explored. Additionally, different causes of stress fractures, as well as various modalities of treatment, are highlighted. Other potential factors of stress fractures were identified by a literature review.

CASE SUMMARY

Six cases of stress fractures in the calcaneus, intermediate cuneiform bone, sacrum, tibia (bilateral), navicular bone and femoral neck are presented, with different types of diagnostic imaging and treatments. All of the cases were associated with an aspect of mobility because all of the patients were physically active in various sport disciplines.

CONCLUSION

The type of therapeutic procedure selected should depend on the specific clinical case, i.e., the patient's condition and level of physical activity.

Evaluating an Algorithm and Clinical Prediction Rule for Diagnosis of Bone Stress Injuries

BACKGROUND

A novel algorithm and clinical prediction rule (CPR), with 18 variables, was created in 2014. The CPR generated a bone stress injury (BSI) score, which was used to determine the necessity of imaging in suspected BSI. To date, there are no validated algorithms for imaging selection in patients with suspected BSI.

HYPOTHESIS

A simplified CPR will assist clinicians with diagnosis and decision making in patients with suspected BSI.

STUDY DESIGN

Prospective cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 778 military trainees with lower extremity pain were enrolled. All trainees were evaluated for 18 clinical variables suggesting BSI. Participants were monitored via electronic medical record review. Then, a prediction model was developed using logistic regression to identify clinical variables with the greatest predictive value and assigned appropriate weight. Test characteristics for various BSI score thresholds were calculated.

RESULTS

Of the enrolled trainees, 204 had imaging-confirmed BSI in or distal to the femoral condyles. The optimized CPR selected 4 clinical variables (weighted score): bony tenderness (3), prior history of BSI (2), pes cavus (2), and increased walking/running volume (1). The optimized CPR with a score ≥3 yielded 97.5% sensitivity, 54.2% specificity, and 98.2% negative predictive value. An isolated measure, bony tenderness, demonstrated similar statistical performance.

CONCLUSION

The optimized CPR, which uses bony tenderness, prior history of BSI, pes cavus, and increased walking/running volume, is valid for detecting BSI in or distal to the femoral condyles. However, bony tenderness alone provides a simpler criterion with an equally strong negative predictive value for BSI decision making.

CLINICAL RELEVANCE

For suspected BSI in or distal to the femoral condyles, imaging can be deferred when there is no bony tenderness. When bony tenderness is present in the setting of 1 or more proven risk factors and no clinical evidence of high-risk bone involvement, presumptive treatment for BSI and serial radiographs may be appropriate.

Nuclear Medicine for the Orthopedic Foot and Ankle Surgeon

Nuclear medicine has been widely applied as a diagnostic tool for orthopedic foot and ankle pathology. Although its indications have diminished with improvements in and the availability of magnetic resonance imaging, nuclear medicine still has a significant and valuable role. The present article offers a comprehensive and current review of the most common nuclear imaging modalities for the orthopedic foot and ankle surgeon. Methods discussed include bone scintigraphy, gallium citrate scintigraphy, labeled-leukocyte scintigraphy, and single-photon emission computed tomography (SPECT). We review the indications and utility of these techniques as they pertain to specific foot and ankle conditions, including osteomyelitis, stress fractures, talar osteochondral lesions, complex regional pain syndrome, oncology, plantar fasciitis, and the painful total ankle arthroplasty. We conclude with a discussion of our approach to nuclear medicine with illustrative cases. Level of Evidence: Level V, expert opinion.

Validation of the Shin Pain Scoring System: A Novel Approach for Determining Tibial Bone Stress Injuries

Background

The incidence of adolescent overuse injuries, including bone stress injuries (BSIs), is on the rise. The identification of a BSI in the early stages is key to successful treatment. The Shin Pain Scoring System (SPSS) was developed to aid clinicians in identifying patients with a BSI.

Hypothesis

The SPSS will correlate with magnetic resonance imaging (MRI) grading of a BSI in an adolescent population.

Study Design

Cohort study (diagnosis); Level of evidence, 2.

Methods

Enrolled in this study were 80 adolescent high school athletes between the ages of 13 and 18 years participating in a variety of sports with more than 1 week of atraumatic shin pain. The SPSS questionnaire was completed for each participant, and physical examination findings were recorded. Each question and physical examination item was allotted a point value, which totaled 29 points. Radiographs and MRI scans of both lower legs were obtained for each participant. The SPSS score was statistically analyzed using logistic regression, a classification matrix, and a 2 × 2 contingency table to evaluate validity and predictability.

Results

Logistic regression analysis of our data determined that 3 categories of SPSS scores provided the highest diagnostic value when compared with MRI grading based on the Fredericson classification (0-4). The SPSS correctly identified 43.5% of injuries for category 1 (MRI grades 0-1), 62.5% for category 2 (MRI grade 2), and 50.0% for category 3 (MRI grades 3-4). Overall, the SPSS correctly identified the degree of BSI in 54.4% of all tibias studied. Binary analysis for validity demonstrated a sensitivity of 96%, specificity of 26%, positive predictive value of 76%, and negative predictive value of 71% for the SPSS relative to the "gold standard" MRI results.

Conclusion

The SPSS is a potentially valid method to identify tibial BSIs, given the sensitivity and negative and positive predictive values. It also provides helpful categorization to alert clinicians to the presence of a BSI and direct further diagnostics and/or interventions. The SPSS should be considered as an additional tool to use when evaluating adolescents with atraumatic tibial BSIs.

Injury Surveillance and Reporting for Trainees with Bone Stress Injury: Current Practices and Recommendations

Background

Musculoskeletal injuries, including lower extremity bone stress injuries (BSI) significantly impact initial entry training (IET) in the U.S. Army due to limited duty days, trainee attrition, early medical discharge, and related financial costs. Factors complicating trainee BSI surveillance include inconsistent BSI coding practices, attrition documentation as both administrative separations and medical discharges and the inability to code for BSI grade or severity when using International Statistical Classification of Diseases and Related Health Problems 10th revision (ICD-10) codes.

Methods

A multidisciplinary expert panel developed policy guidance to enhance clinical and administrative management of BSI, following extensive analysis of current, peer-reviewed literature. Policy guidance incorporates leading practices concerning clinical BSI management, including imaging procedures, recommended notifications, early intervention, and ICD-10 diagnostic coding procedures. Policy guidance also standardizes BSI grading criteria for magnetic resonance imaging and skeletal scintigraphy (bone scan).

Findings

Multidisciplinary expert opinion indicates inconsistent BSI diagnosis and management across IET due to variability in trainee BSI grading, documentation, and coding practices. Injury surveillance conducted by the United States Army Medical Command (USAMEDCOM) will benefit from routine, standardized musculoskeletal injury data base searches by BSI severity/grade and anatomical location upon implementation of BSI policy guidance.

Discussion

Effective injury surveillance is critical for determining trainee BSI incidence and attrition, developing anticipated return to duty (RTD) timelines, and assessing long-term outcomes. BSI RTD timelines should account for gender, BSI grade/severity, anatomical location, and type of intervention. Well-defined RTD timelines would benefit administrative decision-making purposes, including whether to grant convalescent leave or enroll in the Warrior Training and Rehabilitation Program during BSI recovery. Enhanced management procedures may improve initial enlistment completion rates for trainees sustaining at least one BSI who eventually complete IET.

A Review and Proposed Rationale for the use of Ultrasonography as a Diagnostic Modality in the Identification of Bone Stress Injuries

Bone stress injuries are common in military personnel and athletes. The delayed diagnosis of a bone stress injury can lead to a more severe injury that requires a longer period of treatment. The early detection of bone stress injuries is a central part of management. Currently, the reference standard for detecting bone stress injuries is magnetic resonance imaging. However, the expanding use of point-of-care ultrasonography (US) may enable the early detection of bone stress injuries in the clinical setting. In this article, we review the US detection of bone stress injuries, as well as discuss the rationale for the use of US in the diagnosis of these injuries.

Conservative versus surgical treatment of 21 sports horses with osseous trauma in the proximal phalangeal sagittal groove diagnosed by low-field MRI

OBJECTIVE

To compare the outcome following conservative vs surgical management of sports horses with a diagnosis of subchondral bone trauma of the proximal aspect of the proximal phalanx (PP) by low-field MRI.

STUDY DESIGN

Retrospective case series.

ANIMALS

Twenty-one mature sports horses with evidence of high water signal within the proximal sagittal groove of the PP according to low-field MRI of the fetlock, with no definitive radiographic evidence of fracture.

METHODS

Medical records (2010-2017) of horses admitted to 2 referral hospitals were reviewed. Historical, clinical, radiographic, and MRI findings and treatment choice were recorded. Conservative management consisted of confinement to a stall followed by gradual reintroduction to exercise. Surgical management consisted of cortical screw fixation across the proximal aspect of the PP. Long-term outcome was determined by telephone questionnaire or by clinical records review. Fisher's exact test was used to compare outcome between the 2 treatment groups.

RESULTS

Follow-up was available in 17 of 21 horses in the study, including 8 horses treated conservatively and 9 treated surgically. No difference in outcome was detected in this study; 4 of 8 horses were sound after conservative management, and 5 of 9 horses were sound after surgery (P > .99).

CONCLUSION

Approximately half of the horses that had a diagnosis of osseous trauma within the proximal aspect of PP returned to athletic activity, regardless of conservative or surgical management.

CLINICAL SIGNIFICANCE

The prognosis for return to athletic functions in horses with osseous trauma within the proximal aspect of the PP is guarded.

Abdominal Circumference Versus Body Mass Index as Predictors of Lower Extremity Overuse Injury Risk

BACKGROUND

Abdominal circumference (AC) is superior to body mass index (BMI) as a measure of risk for various health outcomes. Our objective was to compare AC and BMI as predictors of lower extremity overuse injury (LEOI) risk.

METHODS

Retrospective review of electronic medical records of 79,868 US Air Force personnel over a 7-year period (2005-2011) for incidence of new LEOI. Subjects were stratified by BMI and AC. Injury risk for BMI/AC subgroups was calculated using Kaplan-Meier curves and Cox proportional-hazards regression. Receiver operating characteristic curves with area under the curve were used to compare each model's predictive value.

RESULTS

Cox proportional-hazards regression showed significant risk association between elevated BMI, AC, and all injury types, with hazard ratios ranging 1.230-3.415 for obese versus normal BMI and 1.665-3.893 for high-risk versus low-risk AC (P < .05 for all measures). Receiver operating characteristic curves with area under the curve showed equivalent performance between BMI and AC for predicting all injury types. However, the combined model (AC and BMI) showed improved predictive ability over either model alone for joint injury, overall LEOI, and most strongly for osteoarthritis.

CONCLUSIONS

Although AC and BMI alone performed similarly well, a combined approach using BMI and AC together improved risk estimation for LEOI.

Epidemiology of imaging-detected bone stress injuries in athletes participating in the Rio de Janeiro 2016 Summer Olympics

BACKGROUND

Bone stress injuries are common in high-level athletics.

AIM

To describe the demographics, frequency and anatomical location of stress injuries (ie, stress reaction and stress fractures) in athletes at the Rio de Janeiro 2016 Summer Olympic Games.

METHODS

We recorded all sports injuries at the Rio de Janeiro 2016 Summer Olympics reported by the National Olympic Committee (NOC) medical teams and in the polyclinic and medical venues. Imaging was performed through the official IOC clinic within the Olympic Village, using digital X-ray cameras and 3T and 1.5T magnetic resonance (MR) scanners. Images were read centrally and retrospectively by musculoskeletal radiologists with expertise in sports injuries.

RESULTS

11 274 athletes (5089 women (45%), 6185 men (55%)) from 207 NOCs participated in the study. 1101 injuries were reported. Imaging revealed 9 stress fractures (36%) and 16 stress reactions (64%) in 18 female and 7 male athletes (median age 25 years, age range 18-32). Stress injuries were mostly in the lower extremities (84%), particularly tibia (44%) and metatarsals (12%), with two in the lumbar spine (8%). Stress injuries were most common in track and field athletes (44%) followed by volleyball players (16%), gymnastics (artistic) (12%) and other type of sports.

CONCLUSIONS

Twenty-five bone stress injuries were reported, more commonly in women, mostly in the lower extremities and most commonly in track and field athletes. Our study demonstrates the importance of early imaging with MRI to detect stress reactions before they can progress to stress fractures.