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.     

Stress fracture of the tarsal navicular

Stress fractures of the lower extremity are common among military members and athletes at all levels of participation. They typically occur when an individual begins a new or different type of physical training or during periods of abrupt increase in the level of training. Stress fractures represent an incomplete remodeling of bone that occurs secondary to repetitive mechanical loading. In response to this increased loading, the osteoclastic resorption of lamellar bone outpaces the ability of the osteoblasts to create new lamellar bone, eventually leading to structural failure. The following case report reviews the typical clinical presentation, imaging findings, and treatment of the tarsal navicular stress fracture.     

Common Pediatric Sports Injuries

This article reviews the common acute and overuse injuries encountered in the pediatric athlete. Acute injuries are usually physeal or avulsion fractures relating to a single traumatic event. Overuse injuries are the result of repetitive stress and include the common traction apophysitis, osteochondritis dissecans, and stress fractures. Sports-related injuries most frequently involve the lower extremity with injury patterns and frequencies relative to the athlete's age, size, and type of sport. Indeed, an alternative title for this review might be òthe adolescent athlete as the changing biomechanics and psychosocial stresses of adolescence are inherent risk factors for sports-related injuries. An estimated seven million adolescents currently play high school sports with an increasing number becoming interested in extreme sports. It is hoped that this review will assist your future encounters with the injured pediatric athlete or òweekend warrior.     

The radiology of sports of injuries

Sports injuries may be either acute or chronic. Most acute injuries occurring in sports are similar to those sustained in other activities, but many have an increased frequency peculiar to a given sport. On the other hand, chronic injury entails repetitive activity which results in repeated stresses applied to various portions of the musculoskeletal system. Prolonged and repeated activity may result in hypertrophy of both muscle and bone. Stress fractures and certain soft-tissue injuries occur when the cumulative effect of the stress exceeds the capacity of the body to repair. Each sport is associated with its own set of peculiar stresses. Knowledge of these peculiar stresses and the potential for injury in any given sports activity can lead to a more accurate diagnosis and satisfactory treatment. We have described many of the injuries associated with radiographic abnormalities.     

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.     

Low-risk stress fractures

Stress fractures can occur in almost any bone in the body, with the lower extremity weightbearing bones, especially the tibia, tarsals, and metatarsals, being affected most frequently. Although the cause of these fractures is multifactoral, repetitive physical forces without adequate rest are the primary culprits. Stress fractures may be broadly classified as low-risk or high-risk injuries. Low-risk stress fractures, the topic of this review article, can be diagnosed through a thorough history, physical examination, and radiographs. Nuclear scintigraphy is occasionally necessary for confirmation, especially for fractures of the spine and pelvis. When diagnosed early and treated with restriction of activity, low-risk stress fractures have a favorable prognosis.     

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.     

Factors associated with discharge during marine corps basic training

This prospective study assessed risk factors for discharge from basic training (BT) among 2,137 male Marine Corps recruits between February and April 2003. Physical and demographic characteristics, exercise, and previous lower extremity injuries before arrival at Marine Corps Recruit Depot were assessed by questionnaire during intake processing. Stress fractures were confirmed by x-ray, triple-phase bone scan, or magnetic resonance imaging. Overall, 223 (10.4%) participants were discharged from training. In addition to the occurrence of a stress fracture during BT, older age (>23 years), non-Hispanic race, poor incoming self-rated physical fitness, no history of competitive exercise, and an incoming lower extremity injury with incomplete recovery were independent risk factors for discharge. Strategies to identify and allow the proper healing time for pre-BT lower extremity injuries, including interventions to improve the physical fitness of recruits before BT and reduce stress fractures during BT, may be indicated to lower attrition.     

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: Current concepts

1. Stress fractures result from muscular activity on bones rather than from direct impact upon them. 2. The fatigue variety of stress fracture occurs in normal bone when abnormal muscular tension or torsion is placed upon it. 3. The insufficiency type of stress fracture results when normal muscular stress is placed upon a bone with deficient elastic resistance. 4. Most stress fractures are of the fatigue type, occurring in an individual who engages in repetitive vigorous activity to which he is unaccustomed. 5. The biomechanics, radiologic features, and differential diagnosis were discussed and the literature was reviewed.     

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.     

Neuropathic bone and joint disease

The pathogenesis of the neuropathic joint has been a subject of controversy for many years. Two main theories of pathophysiologic pathways have evolved: (1) the neurotraumatic, which states that the changes result from mechanical trauma and repetitive injuries to an insensitive extremity or joint and (2) the neurovascular, which states that the changes result from a neurally initiated vascular reflex that leads to hyperemia, angiogenesis, and very active bone resorption by osteoclasts. Through clinical, radiographic, and pathologic observation, it appears evident that both pathways contribute to neuropathic bone and joint disease. Initially, the alteration of sympathetic control triggers a persistent hyperemia, leading to active bone resorption. There may or may not be associated pathologic fractures and subsequent repair. This depends upon the degree of joint insensitivity and whether or not it is subjected to continued weightbearing. If so, the neurotraumatic mechanisms come into play, but only secondarily.     

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.     

Assessing radiographically occult upper extremity fractures with dedicated extremity MRI

Purpose: To examine the utility of low-field, dedicated extremity MRI for assessing acute upper extremity trauma in patients with radiographs that are negative for fracture. Secondly, to determine which sequences are most useful when screening for fractures. Methods: Forty-four of 46 patients with acute upper extremity trauma and initial radiographs negative for fracture were imaged with a 0.2-T MRI system. Findings were verified with follow-up clinical assessment and plain radiography. Results: In 21 patients, dedicated extremity MRI demonstrated 26 ultimately proven occult fractures, none of which were seen on the initial conventional radiographs. True fractures demonstrated marrow edema and a linear fracture line on low-field MRI. One bone contusion showed edema with no fracture line and was misdiagnosed as a fracture. Low-field MRI correctly identified 23 remaining patients with no fracture. Sensitivity and specificity for fracture in the 44 patients successfully imaged were 100 % and 96 %, respectively. Additionally, 21 soft-tissue injuries were found incidentally by MRI. However, these may not merely be incidental findings of an acute nature, but may very well be chronic, and therefore merit no specific treatment. T1-weighted gradient-echo and short-tau inversion recovery sequences demonstrated the fracture line and marrow edema to best advantage, and were thus the most useful sequences to assess fractures on low-field MRI. Conclusion: Extremity MRI is highly sensitive and specific for radiographically occult fractures of the upper extremity and can also identify associated soft-tissue injuries. In our study, the management was altered in 45 % of the patients following MRI. When adequate sequences are used this modality can direct appropriate therapy while obviating the added expense and morbidity of unnecessary immobilization and follow-up imaging of patients without fracture.     

Gymnastic wrist injuries

During gymnastic activities, the wrist is exposed to many different types of stresses, including repetitive motion, high impact loading, axial compression, torsional forces, and distraction in varying degrees of ulnar or radial deviation and hyperextension. Many of these stresses are increased during upper extremity weight-bearing and predispose the wrist to high rates of injury during gymnastics. Distal radius stress injuries are the most common and most documented gymnastic wrist conditions. Other conditions include scaphoid impaction syndrome, dorsal impingement, scaphoid fractures, scaphoid stress reactions/fractures, capitate avascular necrosis, ganglia, carpal instability, triangular fibrocartilage complex tears, ulnar impaction syndrome, and lunotriquetral impingement. It is important to diagnose quickly and accurately the specific injury to initiate expediently the proper treatment and limit the extent of injury. In addition, a gymnast's training regimen should also include elements of injury prevention.     

Basic,Balanced Diet Meets Requirements of Athletes

Abstract

Fractures of the proximal humerus occur frequently, and are primarily insufficiency fractures that occur in the elderly. Thorough clinical evaluation is essential in identifying associated neurovascular injury, which warrants emergent surgical referral. Good quality radiographs remain a necessary diagnostic tool in the evaluation of proximal humerus injuries. An appreciation of the relevant anatomy and predictable patterns of deformation aid in understanding the basic classification of proximal humerus fractures. Most of these fractures are minimally displaced and can be treated nonoperatively with acceptable clinical outcomes. Familiarity with the basic surgical treatment modalities is helpful to physicians involved in the pre- and postoperative management. Significantly displaced proximal humerus fractures are typically treated with surgical reduction and internal fixation. Complex fractures in the elderly and fracture dislocations are indications for humeral head prosthetic replacement. Proximal humerus fractures are strongly associated with decreased bone mineral density and future fracture risk, and should prompt a referral for medical management of osteoporosis.     

Evaluation and management of proximal humerus fractures

Fractures of the proximal humerus occur frequently, and are primarily insufficiency fractures that occur in the elderly. Thorough clinical evaluation is essential in identifying associated neurovascular injury, which warrants emergent surgical referral. Good quality radiographs remain a necessary diagnostic tool in the evaluation of proximal humerus injuries. An appreciation of the relevant anatomy and predictable patterns of deformation aid in understanding the basic classification of proximal humerus fractures. Most of these fractures are minimally displaced and can be treated nonoperatively with acceptable clinical outcomes. Familiarity with the basic surgical treatment modalities is helpful to physicians involved in the pre- and postoperative management. Significantly displaced proximal humerus fractures are typically treated with surgical reduction and internal fixation. Complex fractures in the elderly and fracture dislocations are indications for humeral head prosthetic replacement. Proximal humerus fractures are strongly associated with decreased bone mineral density and future fracture risk, and should prompt a referral for medical management of osteoporosis.     

Tibial Stress Injuries

IN BRIEF: Tibial stress injuries, commonly called'shin splints,’ often result when bone remodeling processes adapt inadequately to repetitive stress. Physicians who care for athletic patients need a thorough understanding of this continuum of injuries, including medial tibial stress syndrome and tibial stress fractures, because there are implications for appropriate diagnosis, management, and prevention.     

Preoperative assessment of the cancellous bone mineral density of the proximal humerus using CT data

Background  

Osteoporotic fractures of the proximal humerus show an increasing incidence. Osteoporosis not only influences the fracture risk after low-energy trauma, but also affects the mechanical stability of internal fixation. Preoperative assessment of the local bone quality may be useful in the surgical treatment of patients sustaining these injuries. The aim of the present study was to present a method for the preoperative assessment of the local cancellous bone mineral density (BMD) of the proximal humerus using CT data.