Management of Femoral Neck Stress Fractures

Stress fractures are being diagnosed more frequently as the resulf of our increased suspicion and their increasing prevalence. The history and physical examination will usually place stress fractures on the differential diagnosis, and the situation is further clarified by an assessment of the potential intrinsic and extrinsic contributing factors. Plain radiographs will often confirm the diagnosis, but if not further imaging will be required. If an insufficiency fracture is suspected then MRI and bone scan should be considered, but if a stress fracture is more likely then just MRI will suffice. If the fracture is displaced I prefer a CT instead of the MRI.With imaging, the fracture can be classified and, in conjunction with the patient’s expectations, an appropriate treatment course can be selected. Improved outcomes largely depend on shorter duration of symptoms, shorter times to diagnosis, low-risk fractures, lesser fracture type and appropriate treatment. When surgery is performed the goals are rapid identification of the fracture, early anatomic reduction, removal of varus neck angle and placement of the fracture line in as horizontal an orientation as reasonable.Mild fractures in the recreational athlete will lead to a period of decreased activity, rapid healing, and return to full activity. More severe fractures will require more intervention and a significantly longer interruption in their activities. It is crucial that the treating physician focus on the long term outcome and inform the patient that this will require 6 to 18 months of treatment before full activity can be reinitiated. It is unlikely that elite or professional athletes or those with high-risk fractures will be able to return to their careers.     

Changes in stress fracture distribution and current treatment

Stress fractures were originally recognized as a problem in the military. As more people undertake strenuous training, the distribution of stress fractures has changed. Some of the difficulties in the discussion of stress fractures are the lack of a consistent definition and the variable sensitivity and specificity of different radiographic techniques. The definition proposed here involves the development of clinical symptoms with a corresponding radiographic change. A high index of suspicion must be maintained to pursue the diagnosis; plain radiographs are often initially negative and may never show characteristic changes. For treatment purposes, stress fractures can be grouped into high-risk and low-risk groups. Low-risk groups can be treated similarly and usually with excellent results, whereas high-risk stress fractures require a more cautious and specific approach.     

Sonographic findings in stress fractures of the lower limb: preliminary findings

Stress fractures are common injuries frequently overlooked on first radiographs, especially in the early course. The gold standard for accurate diagnosis is MRI and scintigraphy. We report six cases of stress fractures of the lower limb diagnosed with sonography and describe typical sonographic features.     

Stress fractures around the knee

Stress fractures of the lower extremities are common, especially in the younger athletic population. The current literature consists mainly a variety of case reports but is devoid of any sizeable series of knee stress fracture investigations. Diagnosing a stress fracture around the knee can be a challenge. The proximity of the stress fracture to the knee joint may lead the clinician to investigate intra-articular or other periarticular pathology. The differential diagnosis can be large, including bursitis, tendonitis, mechanical causes, insufficiency fracture, and tumor. A high index of suspicion is necessary to confirm the underlying diagnosis. A patient's medical history combined with a physical examination and imaging modalities will aid the physician in arriving at the diagnosis of stress fracture.     

Stressfrakturen

Bone stress injuries are due to repetitive mechanical overuse of the skeleton and occur as a result of microscopic lesions sustained when bone is subjected to repeated submaximal stress. Over time accumulation of such injuries can lead to bone failure and fractures. Stress-related bone injuries are relatively common among otherwise healthy persons who have recently started new or intensified forms of physical training activities. Stress injuries lead to typical findings on radiography, bone scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI) and need to be discriminated from other conditions, in particular infections and neoplasms. Stress fractures must be differentiated from insufficiency fractures that occur in bones with reduced mechanical resistance or disturbed structure.     

Stress fractures in the female athlete

Stress fractures are common among female athletes, especially runners. Although both intrinsic and extrinsic factors can contribute to stress injury etiology, the female athlete triad—negative energy balance leading to menstrual irregularity, and reduced bone mineral mass—is a significant contributor to the incidence of stress fractures in the female athlete. When combined with impact weight-bearing activity, this triad puts these women at increased risk for stress fractures. Treatment must focus on reversing identified risk factors, in addition to relative rest, and maintenance of fitness. Most stress fractures heal without complication. High-risk stress fractures should be evaluated and treated by a practitioner with expertise in the care of these injuries.     

Lower thoracic rib stress fractures in baseball pitchers

Stress fractures of the first rib on the dominant throwing side are well-described in baseball pitchers; however, lower thoracic rib fractures are not commonly recognized. While common in other sports such as rowing, there is scant literature on these injuries in baseball. Intercostal muscle strains are commonly diagnosed in baseball pitchers and have a nearly identical presentation but also a highly variable healing time. The diagnosis of a rib stress fracture can predict a more protracted recovery. This case series presents two collegiate baseball pitchers on one team during the same season who were originally diagnosed with intercostal muscle strains, which following magnetic resonance imaging (MRI) were found to have actually sustained lower thoracic rib stress fractures. The first sustained a stress fracture of the posterior aspect of the right 8th rib on the dominant arm side, while the second presented with a left-sided 10th rib stress fracture on the nondominant arm side. In both cases, MRI was used to visualize the fractures as plain radiographs are insensitive and commonly negative early in patient presentation. Patients were treated with activity modification, and symptomatic management for 4–6 weeks with a graduated return to throwing and competition by 8–10 weeks. The repetitive high stresses incurred by pitching may cause either dominant or nondominant rib stress fractures and this should be included in the differential diagnosis of thoracic injuries in throwers. It is especially important that athletic trainers and team physicians consider this diagnosis, as rib fractures may have a protracted course and delayed return to play. Additionally, using the appropriate imaging techniques to establish an accurate diagnosis can help inform return-to-play decisions, which have important practical applications in baseball, such as roster management and eligibility.     

Delay in diagnosis of neck of femur stress fracture in a female military recruit

We report the delay in diagnosis of a Neck of Femur (NOF) stress fracture in mixed sex basic military training. Stress fractures are common in military training with the incidence reported as ranging between 3.2-31%. NOF stress fractures, whilst only representing around 8% of stress fractures are associated with a high morbidity. It is imperative that medical officers looking after military recruits have a sound knowledge of the potential signs, symptoms and presentation of these injuries. Medical officers should always remains vigilant for stress fractures especially in mixed military training.     

Scintigraphic uptake of 99mTc at non-painful sites in athletes with stress fractures. The concept of bone strain

Stress fractures are commonly found in athletes attending sports medicine clinics for diagnosis of lower limb pain. Plain radiographs are less reliable than the 99mTc bone scan for diagnosing stress fractures because of their low sensitivity. While the heightened sensitivity of the bone scan is advantageous as a diagnostic aid, the uptake of 99mTc at non-painful sites occurs frequently in the athlete. Although the clinical significance has not been determined, asymptomatic uptake may indicate bone remodelling as part of a continuum of adaptation to physical stress. It is not known whether athletes who have uptake of 99mTc in asymptomatic areas represent a separate population from those who do not. This study retrospectively reviewed the medical charts and bone scan reports of 320 athletes diagnosed as having stress fractures, to determine the frequency of asymptomatic focal uptake at sites other than the site of pain. This group was compared with the group who had no asymptomatic uptake on a number of demographic variables and physical findings. Asymptomatic focal uptake was found in 37.5% of athletes with the average number of sites being 1.8 per person. No significant differences between groups with focal asymptomatic uptake and groups with no asymptomatic uptake were found when compared for age, height, weight, mileage in runners, times to diagnosis and recovery, frequency of tenderness, swelling, trauma history, varus alignment, and x-ray abnormalities. It is concluded that asymptomatic uptake of 99mTc occurs frequently in athletes with stress fractures and there are no significant clinical differences between the group with asymptomatic uptake and the group without. It is suggested that symptomatic uptake of 99mTc represents the remodelling response of bone to physical stress.     

Stress fractures in athletes

Stress fractures may pose a diagnostic dilemma for radiologists since they are sometimes difficult to demonstrate on plain films and may simulate a tumour. They were first described in military personnel and professional athletes. Recently, there is an increasing incidence in the general population due to increasing sportive activities. Stress fractures occur most often in the lower extremities, especially in the tibia, the tarsal bone, the metatarsal bone, the femur and the fibula. In the upper extremities, they are commonly found in the humerus, the radius and the ulna. Some fractures of the lower extremities appear to be specific for particular sports, for example, fractures of the tibia affect mostly distance runners. Whereas stress fractures of the upper extremities are generally associated with upper limb-dominated sports. A correct diagnosis requires a careful clinical evaluation. The initial plain radiography may be normal. Further radiological evaluation could be performed by means of computerised tomography, magnetic resonance imaging and bone scanning. The latter two techniques are especially helpful for establishing a correct initial diagnosis.     

Stress fractures in young athletic women: case reports of unsuspected cortisol-induced osteoporosis.

Stress fractures in the female athlete are common events, usually occurring in the lower limb and less often in the pelvic girdle. Two cases are presented of young women athletes who presented with initial lower limb stress fractures, but subsequently fractures of the pelvis and hip thought to be associated with their athletic activity. After careful medical evaluation, they were diagnosed with Cushing's syndrome. One patient had a microadenoma of the pituitary gland secreting excessive amounts of ACTH, and the other had a benign adenoma of the left adrenal gland. Both women had significant decreases in their spinal mineral density. After treatment, partial reversal of these spinal losses occurred. Although stress fractures in the female athlete might be common and thought to be associated with problems of amenorrhea, presentation of unusual anatomical sites for these fractures necessitates a more thorough evaluation for correctable secondary causes.     

Stress fractures in the young athlete: a pictorial review

Stress fractures are an uncommon but important source of pain and disability in young athletes. The presentation and differential diagnosis of stress fractures in young athletes differs from that of older athletes. This pictorial review outlines the pathogenesis and imaging features of stress fractures. Other pathologies that can mimic stress fractures and the advantages of the use of magnetic resonance imaging will be discussed. An imaging algorithm for a suspected stress fracture is suggested.     

Acetabular stress fractures in military endurance athletes and recruits: incidence and MRI and scintigraphic findings

OBJECTIVE: To evaluate the incidence and the MRI and scintigraphic appearance of acetabular stress (fatigue) fractures in military endurance athletes and recruits. DESIGN AND PATIENTS: One hundred and seventy-eight active duty military endurance trainees with a history of activity-related hip pain were evaluated by both MRI and bone scan over a 2-year period. Patients in the study ranged in age from 17 to 45 years. They had hip pain related to activity and had plain radiographs of the hip and pelvis that were interpreted as normal or equivocal. The study was originally designed to evaluate the MRI and scintigraphic appearance of femoral neck stress fractures. Patients had scintigraphy and a limited MRI examination (coronal imaging only) within 48 h of the bone scan. Twelve patients demonstrated imaging findings compatible with acetabular stress fractures. RESULTS: Stress fractures are common in endurance athletes and in military populations; however, stress fracture of the acetabulum is uncommon. Twelve of 178 patients (6.7%) in our study had imaging findings consistent with acetabular stress fractures. Two patterns were identified. Seven of the 12 (58%) patients had acetabular roof stress fractures. In this group, two cases of bilateral acetabular roof stress fractures were identified, one with a synchronous tensile sided femoral neck stress fracture. The remaining five of 12 (42%) patients had anterior column stress fractures, rarely occurring in isolation, and almost always occurring with inferior pubic ramus stress fracture (4 of 5, or 80%). One case of bilateral anterior column stress fractures was identified without additional sites of injury. CONCLUSIONS: Stress fractures are commonplace in military populations, especially endurance trainees. Acetabular stress fractures are rare and therefore unrecognized, but do occur and may be a cause for activity-related hip pain in a small percentage of military endurance athletes and recruits.     

Part II: presentation,diagnosis, classification,treatment, and prevention of stress fractures in female athletes

ABSTRACT

Objectives: Stress fractures (SFx) occur as the result of repetitive loads over short periods of time, which leads to micro-damage of the bone through cortical resorption, ultimately leading to fracture. They are a common injury in female athletes and often cause significant morbidity. The goal of this study is to review the presentation, diagnosis, classification, treatment, and prevention of SFx in female athletes.

Results: A thorough history, physical exam, and appropriate imaging can facilitate early diagnosis of stress fracture (SFx) and faster resolution of symptoms with more conservative management. The female athlete triad is an especially important factor that contributes to the increased risk of SFx in females. The continuum of stress injuries ranges from mild microfailure to complete fracture, which has resulted in the development of newer grading schemas through MRI and radiographic findings. Stress fractures are also classified as low- or high-risk according to anatomic location, as blood supply and applied forces at different locations affect the likelihood of fracture propagation, displacement, delayed union, or non-union.

Conclusions: The ability to screen for at-risk athletes is paramount in preventing SFx. Recognition and prompt treatment of the female athlete triad requires a multidisciplinary approach in order to restore energy balance, correct menstrual irregularities, and improve bone health. This review provides a basis for understanding how to identify and treat stress fractures, which may allow treating physicians to diagnose this condition earlier and minimize any associated morbidity.     

Stress fractures: classification and management

Stress fractures occur as a result of microdamage secondary to repetitive strains. A mechanism for the development of stress fractures involves the accumulation of microdamage, which occurs with multiple subultimate failure loads applied to the bone. Stress fractures may be classified as high or low risk, depending on the grade of the injury. The most common site of injury is the lower extremity. In this article, we review the pathophysiology, etiology, diagnosis, and management of stress fractures, and present treatment guidelines for return to play.     

Stress fractures of the upper extremity

Stress fractures are common injuries in the athletic population. Although much of the published literature has focused on lower extremity stress injuries, these injuries also occur in the upper extremities. Stress injuries of bone result from repetitive loads smaller than would be required to cause an acute fracture. As bone is repetitively stressed, it behaves like any solid substance. If deformity occurs within its elastic range, it returns to its original configuration. If stressed into its plastic range, permanent deformity occurs, and microfractures propagate, causing structural failure and complete fracture of the involved bone. High clinical suspicion is required for diagnosis because of historical and physical features can be vague. Plain radiographs are often inconclusive, but bone scans and MR imaging usually help elucidate the diagnosis. Most upper extremity stress injuries will heal with nonoperative management. In rare situations these injuries can progress to nonunion, which requires surgical correction.     

Imaging of stress fractures of the spine

Back pain caused by stress fractures, fatigue, or insufficiency, affects varied patient populations based on the level of physical activity and bone mineral density. Stress fractures may involve the vertebral body, pars interarticularis, and the pedicle; often overlooked are stress fractures of the sacrum or bony pelvis, which can mimic pain of spinal origin and delay diagnosis. The choice of optimal imaging (radiographs, nuclear medicine, magnetic resonance imaging, and computed tomography) also depends on the patient population under study and the clinically suspected diagnosis. The diagnosis typically determines which imaging modality is best to follow healing or progression.     

Second metatarsal stress fracture in sport: comparative risk factors between proximal and non-proximal locations

Background

Stress fractures of the second metatarsal are common injuries in athletes and military recruits. There are two distinct areas in the second metatarsal where stress fractures develop: one proximal (at the base) and the other non‐proximal (distal). Diagnosis can be difficult, and there is a difference in prognosis and treatment of the two types of stress fracture. Therefore differentiation of fracture location is warranted. Differences in risk factors and clinical outcomes between proximal and non‐proximal stress fractures have not been studied.

Objective

To determine whether different risk factors and/or clinical outcomes associated with proximal and non‐proximal stress fractures of the second metatarsal exist.

Methods

Patients diagnosed with proximal stress fractures of the second metatarsal were included in the study. Retrospectively, an age‐matched control group with a non‐proximal stress fracture was selected for comparison. Statistical analysis involved bivariate comparisons of demographic variables and clinical measurement between the two groups.

Results

Patients with proximal stress fractures were more likely to be chronically affected, usually exhibited an Achilles contracture, showed differences in length of first compared with second metatarsal, were more likely to experience multiple stress fractures, and exhibited low bone mass. In addition, a high degree of training slightly increased the risk of a non‐proximal fracture, whereas low training volume was associated with a proximal stress fracture.

Conclusion

The signs, symptoms and clinical findings associated with proximal metatarsal stress fractures are different from those of non‐proximal stress fractures.     

Stress fractures in the lower extremity. The importance of increasing awareness amongst radiologists

Stress fractures are fatigue injuries of bone usually caused by changes in training regimen in the population of military recruits and both professional and recreational athletes. Raised levels of sporting activity in today's population and refined imaging technologies have caused a rise in reported incidence of stress fractures in the past decades, now making up more than 10% of cases in a typical sports medicine practice. Background information (including etiology, epidemiology, clinical presentation and treatment and prevention) as well as state of the art imaging of stress fractures will be discussed to increase awareness amongst radiologists, providing the tools to play an important role in diagnosis and prognosis of stress fractures. Specific fracture sites in the lower extremity will be addressed, covering the far majority of stress fracture incidence. Proper communication between treating physician, physical therapist and radiologist is needed to obtain a high index of suspicion for this easily overlooked entity. Radiographs are not reliable for detection of stress fractures and radiologists should not falsely be comforted by them, which could result in delayed diagnosis and possibly permanent consequences for the patient. Although radiographs are mandatory to rule out differentials, they should be followed through when negative, preferably by magnetic resonance imaging (MRI), as this technique has proven to be superior to bone scintigraphy. CT can be beneficial in a limited number of patients, but should not be used routinely.