William Beaumont Army Medical Center

BACKGROUND: Ankle sprain has been studied in athletic cohorts, but little is known of its epidemiology in the general population. A longitudinal, prospective epidemiological database was used to determine the incidence and demographic risk factors for ankle sprains presenting to emergency departments in the United States. It was our hypothesis that ankle sprain is influenced by sex, race, age, and involvement in athletics. METHODS: The National Electronic Injury Surveillance System (NEISS) was queried for all ankle sprain injuries presenting to emergency departments between 2002 and 2006. Incidence rate ratios were then calculated with respect to age, sex, and race. RESULTS: During the study period, an estimated 3,140,132 ankle sprains occurred among an at-risk population of 1,461,379,599 person-years for an incidence rate of 2.15 per 1000 person-years in the United States. The peak incidence of ankle sprain occurred between fifteen and nineteen years of age (7.2 per 1000 person-years). Males, compared with females, did not demonstrate an overall increased incidence rate ratio for ankle sprain (incidence rate ratio, 1.04; 95% confidence interval, 1.00 to 1.09). However, males between fifteen and twenty-four years old had a substantially higher incidence of ankle sprain than their female counterparts (incidence rate ratio, 1.53; 95% confidence interval, 1.41 to 1.66), whereas females over thirty years old had a higher incidence compared with their male counterparts (incidence rate ratio, 2.03; 95% confidence interval, 1.65 to 2.65). Compared with the Hispanic race, the black and white races were associated with substantially higher rates of ankle sprain (incidence rate ratio, 3.55 [95% confidence interval, 1.01 to 6.09] and 2.49 [95% confidence interval, 1.01 to 3.97], respectively). Nearly half of all ankle sprains (49.3%) occurred during athletic activity, with basketball (41.1%), football (9.3%), and soccer (7.9%) being associated with the highest percentage of ankle sprains during athletics. CONCLUSIONS: An age of ten to nineteen years old is associated with higher rates of ankle sprain. Males between fifteen and twenty-four years old have higher rates of ankle sprain than their female counterparts, whereas females over thirty years old have higher rates than their male counterparts. Half of all ankle sprains occur during athletic activity.

BACKGROUND: The epidemiology of traumatic shoulder dislocations is poorly understood. The aim of the current study was to determine the incidence of shoulder dislocations presenting to hospital emergency departments in the United States and define demographic risk factors for these injuries. METHODS: The National Electronic Injury Surveillance System, a probability sample of all injuries presenting to emergency departments in the United States, was queried for shoulder dislocations from 2002 through 2006. Patient and injury characteristics were analyzed. United States Census data were utilized to calculate incidence rates for the United States population and subgroups. Incidence rate ratios were then calculated with respect to age, sex, and race. RESULTS: A total of 8940 shoulder dislocations were identified, resulting in an overall incidence rate in the United States of 23.9 (95% confidence interval, 20.8 to 27.0) per 100,000 person-years. The male incidence rate was 34.90 (95% confidence interval, 30.08 to 39.73) per 100,000 person-years, with an incidence rate ratio of 2.64 (95% confidence interval, 2.39 to 2.88) relative to the female incidence rate. It was found that 71.8% of the dislocations were in males. Stratified by decade, the maximum incidence rate (47.8 [95% confidence interval, 41.0 to 54.5]) occurred in those between the ages of twenty and twenty-nine years; 46.8% of all dislocations were in patients between fifteen and twenty-nine years of age. There were no significant differences based on race. Dislocations most frequently resulted from a fall (58.8%) and occurred at home (47.7%) or at sites of sports or recreation (34.5%). Overall, 48.3% of injuries occurred during sports or recreation. CONCLUSIONS: The estimated incidence rate of shoulder dislocations in the United States is 23.9 per 100,000 person-years, which is approximately twice the previously reported value. A young age and male sex are risk factors for shoulder dislocation in the United States population.

BACKGROUND: Little is known about the injury rates in Major League Baseball (MLB) players, as a formal injury surveillance system does not exist. The goal of this study was to characterize the epidemiology of MLB injuries over a 7-year period. HYPOTHESIS: Injuries in MLB would be common. STUDY DESIGN: Descriptive epidemiologic study. METHODS: The authors analyzed the MLB disabled list data from 2002 through 2008. Injuries were analyzed for differences between seasons, as well as during seasons on a monthly basis. The injuries were categorized by major anatomic zones and then further stratified based on injury type. Position-specific subanalyses for pitcher and position players were performed. RESULTS: From the 2002 season through the 2008 season, an average of 438.9 players per year were placed on the disabled list, for a rate of 3.61 per 1000 athlete-exposures. There was a significant 37% increase in injuries between 2005 and 2008. The highest injury rate during the season was during the month of April (5.73/1000 exposures) and the lowest in September (0.54/1000 exposures). No differences were noted in the injury rates between the National League and the American League (incidence rate ratio [IRR] = 1.06; 95% confidence interval [CI] = 0.98, 1.15). Pitchers experienced 34% higher incidence rates for injury compared with fielders during the study period (IRR = 1.34; 95% CI = 1.25, 1.44). Among all player injuries, upper extremity injuries accounted for 51.4% while lower extremity injuries accounted for 30.6%. Injuries to the spine and core musculature accounted for 11.7% while other injuries and illnesses were 6.3% of the total disabled list entries. There was a significant association between position played and anatomic region injured (P < .001), with pitchers experiencing a significantly greater proportion of injuries to the upper extremity (67.0%; 95% CI = 63.1%, 70.9%) compared with fielders (32.1%; 95% CI = 29.1%, 35.1%). Conversely, fielders experienced a significantly greater proportion of injuries to the lower extremity (47.5%; 95% CI = 43.8%, 51.1%) compared with pitchers (16.9%; 95% CI = 14.9%, 18.8%). The mean number of days on the disabled list was 56.6. Overall, a greater proportion of disability days were experienced by pitchers (62.4%; 95% CI = 62.0%, 62.8%; P < .001) compared with fielders (37.6%; 95% CI = 37.3%, 37.9%). CONCLUSION: Injuries in MLB resulting in disabled list designation are common. Upper extremity injuries were predominant in pitchers, while lower extremity injuries are more common in position players. These data may be used in the development of a formal MLB injury database, as well as in the development and implementation of specific preseason training and in-season conditioning for injury prevention.

BACKGROUND: This investigation sought to identify risk factors for immediate postoperative morbidity and mortality among a large series of patients undergoing spine surgery who were prospectively entered into a national registry. METHODS: The database of the National Surgical Quality Improvement Program was queried to identify all patients undergoing spine surgery in the years 2005 to 2008. Demographic data, comorbidities, medical history, body-mass index, and the type of procedure performed were obtained for all patients. Postoperative complications and mortality within thirty days after the spinal procedure were also documented. The chi-square test and univariate and multivariate logistic regression analyses were used to evaluate the effect of individual risk factors on mortality, as well as the probability of the development of complications. RESULTS: From 2005 to 2008, 3475 patients undergoing spine surgery were registered in the database. The average age of patients was 55.5 years (range, sixteen to ninety years), and 54% of the cohort were men. Ten patients (0.3%) died after surgery, and there were 407 complications in 263 patients (7.6%). Increased patient age and contaminated or infected wounds were identified as independent predictors of mortality. Increased patient age, cardiac disease, preoperative neurologic abnormalities, prior wound infection, corticosteroid use, history of sepsis, American Society of Anesthesiologists classification of >2, and prolonged operative times were independent predictors for the development of one or more complications. CONCLUSIONS: Patient age, female sex, longer procedural times, and several types of medical comorbidities influenced the risk of postoperative complications or mortality. This information enhances estimates of morbidity and mortality following spine surgery and may improve patient selection for spine surgery as well as preoperative discussions related to the risks of spine surgery.

BACKGROUND: Human babesiosis is a tickborne malaria-like illness that generally resolves without complication after administration of atovaquone and azithromycin or clindamycin and quinine. Although patients experiencing babesiosis that is unresponsive to standard antimicrobial therapy have been described, the pathogenesis, clinical course, and optimal treatment regimen of such cases remain uncertain. METHODS: We compared the immunologic status, clinical course, and treatment of 14 case patients who experienced morbidity or death after persistence of Babesia microti infection, despite repeated courses of antibabesial treatment, with those of 46 control subjects whose infection resolved after a single course of standard therapy. This retrospective case-control study was performed in southern New England, New York, and Wisconsin. RESULTS: All case patients were immunosuppressed at the time of acute babesiosis, compared with <10% of the control subjects. Most case patients experienced B cell lymphoma and were asplenic or had received rituximab before babesial illness. The case patients were more likely than control subjects to experience complications, and 3 died. Resolution of persistent infection occurred in 11 patients after 2-10 courses of therapy, including administration of a final antimicrobial regimen for at least 2 weeks after babesia were no longer seen on blood smear. CONCLUSIONS: Immunocompromised people who are infected by B. microti are at risk of persistent relapsing illness. Such patients generally require antibabesial treatment for >or=6 weeks to achieve cure, including 2 weeks after parasites are no longer detected on blood smear.

BACKGROUND: Glenohumeral instability is a common injury sustained by young athletes. Surprisingly, little is known regarding the incidence of glenohumeral instability in collegiate athletes or the relevant risk factors for injury. A better understanding of the populations most at risk may be used to develop preventive strategies. HYPOTHESIS: The incidence of glenohumeral instability in collegiate athletics is high, and it is affected by sex, sport, type of event, and mechanism of injury. STUDY DESIGN: Descriptive epidemiologic study. METHODS: The National Collegiate Athletic Association injury database was queried for all glenohumeral instability events occurring between the years 1989 and 2004. An analysis of the injuries was performed by sport, activity (competition versus practice), sex, type of event (primary versus recurrent), mechanism of injury, and time loss from athletic performance. Incidence rates and incidence rate ratios were calculated. RESULTS: A total of 4080 glenohumeral instability events were documented for an incidence rate of 0.12 injuries per 1000 athlete exposures. The sport with the greatest injury rate was men's spring football, with 0.40 injuries per 1000 athlete exposures. Overall, athletes sustained more glenohumeral instability events during games than practices (incidence rate ratio [IRR], 3.50; 95% confidence interval [CI], 3.29-3.73). Male athletes sustained more injuries than did female athletes (IRR, 2.67; 95% CI, 2.43-2.93). Female athletes were more likely to sustain an instability event as the result of contact with an object (IRR, 2.43; 95% CI, 2.08-2.84), whereas male athletes were more likely to sustain an event from player contact (IRR, 2.74; 95% CI, 2.31-3.25). Time lost to sport (>10 days) occurred in 45% of glenohumeral instability events. CONCLUSION: Glenohumeral instability is a relatively common injury sustained by collegiate athletes. More injuries occurred during competition and among male athletes.

PURPOSE: The aim of this study was to review and describe the cumulative incidence of anterior cruciate ligament (ACL) graft rupture and/or clinical objective failures at greater than 10 years after ACL reconstruction. METHODS: A PubMed search was performed to identify and systematically evaluate all studies performed between 1980 and 2012 with clinical outcomes after intra-articular, non-artificial ACL reconstruction and minimum 10-year follow-up. Studies reporting standardized surgical technique, ACL graft rupture, and objective International Knee Documentation Committee (IKDC) grade or ligament stability examination were included for analysis. After we first identified patients with graft rupture, clinical failure was further identified as 1 or more of the following: overall IKDC objective score of C or D, IKDC grade C or D pivot shift (i.e., >2+ or pivot shift), IKDC grade C or D Lachman examination, and/or abnormal KT arthrometer (MEDmetric, San Diego, CA) measurement (i.e., >5 mm). For this study, cumulative ACL failure rates were defined as the sum of both clinical failures and ACL graft ruptures. RESULTS: After review and exclusion of 625 references, 14 studies were identified for subsequent review. At longer than 10 years' clinical follow-up, the reported ACL graft rupture rate was 6.2% (173 of 2,782) (range, 0% to 13.4%) and clinical failure occurred in approximately 10.3% (158 of 1,532) (range, 1.9% to 25.6%). The overall cumulative ACL failure rate was 11.9% (range, 3.2% to 27%). CONCLUSIONS: At least 1 in 9 patients undergoing ACL reconstruction will have rerupture or clinical failure at long-term follow-up. LEVEL OF EVIDENCE: Level IV, systematic review of Level II and IV studies.

Abstract To investigate the effects of sleep deprivation on medical interns, an electrocardiographic arrhythmia-detection task and questionnaires assessing mood and subjectively perceived psychophysiologic state were administered. In comparison to their performance when rested, interns deprived of sleep were significantly less able to recognize arrhythmias on the electrocardiographic task. Mood was significantly affected by sleep loss; deprived interns felt increased sadness and decreased vigor, egotism and social affection. In addition, numerous psychopathologic symptoms developed, and they judged themselves to have abnormalities in cognitive, perceptual and physiologic areas of function. It is apparent that interns deprived of normal sleep may experience transient psychopathology and impaired efficiency of performance.

Background: Little is known of the incidence of shoulder instability, despite some evidence that it may be a common injury in young, athletic individuals. The goal of this study was to determine the incidence of shoulder dislocation in United States military personnel, as well as to identify the demographic risk factors for injury. Methods: We performed a query of the Defense Medical Epidemiology Database with the code from the International Classification of Diseases, Ninth Revision, for acute shoulder dislocation for the years 1998 through 2006. An overall injury incidence was calculated, in addition to multivariate analysis, to determine independent risk factors among the following demographic considerations: sex, race, branch of military service, rank, and age. Results: The overall incidence rate was 1.69 dislocations per 1000 person-years. Significant demographic risk factors were male sex, white race, service in the Army, junior enlisted rank, and an age of less than thirty years (p< 0.0001). Conclusions: The incidence of shoulder instability among U.S. military personnel (1.69 per 1000 person-years) is considerably higher than previous reports for the general U.S. population (0.08 per 1000 person-years). Male sex, white race, and an age of less than thirty years were significant independent risk factors for injury. Clinical Relevance: Shoulder dislocation is endemic in the military population. While this may not be generalizable to the general U.S. population, this incidence rate may be reflective of young, athletic cohorts. An improved understanding of the demographic groups at risk can be used to develop future preventive strategies.

BACKGROUND: Ankle sprain is a common injury in athletic populations that results in significant time lost to injury. HYPOTHESIS: The incidence rates (IRs) of ankle ligament sprains are influenced by gender, height, weight, body mass index (BMI), physical conditioning, level of competition, type of sport, and athlete exposure to sport. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A longitudinal cohort study was performed to determine the effect of risk factors for ankle sprain at the United States Military Academy between 2005 and 2007. RESULTS: A total 614 cadets sustained new ankle sprains during 10 511 person-years at risk, resulting in an overall IR of 58.4 per 1000 person-years. Women (96.4), compared with men (52.7), had a significantly increased rate ratio (IRR) for ankle sprain of 1.83 (95% confidence interval [CI], 1.52-2.20). Men with ankle sprains had higher mean height, weight, and BMI than uninjured men (P <.001). Men with ankle sprains had higher average scores in push-ups, sit-ups, and run time than uninjured men (P <.001). Ankle sprain occurred most commonly during athletics (64.1%). Ankle sprain IR did not significantly differ between intercollegiate and intramural athletic competition after controlling for athlete-exposure (IRR, 1.05; 95% CI, 0.81-1.37). The ankle sprain IRR of female compared with male intercollegiate athletes was 0.93 (95% CI, 0.67-1.32) per 1000 person-years and 1.04 (95% CI, 0.74-1.47) per 1000 athlete-exposures. The intercollegiate sports of men's rugby, women's cheerleading, and men's/women's basketball, soccer, and lacrosse had the highest ankle sprain IR. CONCLUSION: Higher mean height and weight in men, increased BMI in men, greater physical conditioning in men, and athlete exposure to selected sports were all risk factors for ankle sprain.

BACKGROUND: Two previous studies have examined the association between an increased posterior tibial slope and anterior cruciate ligament (ACL) injuries as measured on plain radiographs. The study results were contradictory, with 1 reporting a statistical difference and the other showing no association. PURPOSE: To determine if there is a difference in posterior tibial slope angle between patients with a history of noncontact ACL injury and a control group with no history of ACL injury. A secondary objective was to examine differences in tibial slope angle between male and female subjects within each group. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: We identified all noncontact ACL injuries that were treated operatively at the United States Military Academy, West Point, New York, from 2004 to 2007. We digitally measured the posterior tibial slope from plain film radiographs of 140 noncontact ACL injuries, stratified them by sex, and compared them with a control cohort of 179 patients and radiographs. RESULTS: Subjects in the noncontact ACL group had significantly greater slope angles (9.39 degrees +/- 2.58 degrees) than did control subjects (8.50 degrees +/- 2.67 degrees) (P = .003). The trend toward greater tibial slope angles in the noncontact ACL group was also observed when each sex was examined independently; however, the difference was only statistically significant for the female subjects between the injury and control groups (9.8 degrees +/- 2.6 degrees vs 8.20 degrees +/- 2.4 degrees) (P = .002). CONCLUSION: Despite the identification of an increased posterior tibial slope as a possible risk factor for women, more research that combines the multifactorial nature of an ACL injury must be performed.

BACKGROUND: Under combat conditions infectious disease can become a major threat to military forces. During Operation Desert Shield, there were numerous outbreaks of diarrhea among the U.S. forces. To evaluate the causes of and risk factors for diarrheal disease, we collected clinical and epidemiologic data from U.S. troops stationed in northeastern Saudi Arabia. METHODS: Between September and December 1990, stool cultures for enteric pathogens were obtained from 432 military personnel who presented with diarrhea, cramps, vomiting, or hematochezia. In addition, a questionnaire was administered to 2022 soldiers in U.S. military units located in various regions of Saudi Arabia. RESULTS: A bacterial enteric pathogen was identified in 49.5 percent of the troops with gastroenteritis. Enterotoxigenic Escherichia coli and Shigella sonnei were the most common bacterial pathogens. Of 125 E. coli infections, 39 percent were resistant to trimethoprim-sulfamethoxazole, 63 percent to tetracycline, and 48 percent to ampicillin. Of 113 shigella infections, 85 percent were resistant to trimethoprim-sulfamethoxazole, 68 percent to tetracycline, and 21 percent to ampicillin. All bacterial isolates were sensitive to norfloxacin and ciprofloxacin. After an average of two months in Saudi Arabia, 57 percent of the surveyed troops had at least one episode of diarrhea, and 20 percent reported that they were temporarily unable to carry out their duties because of diarrheal symptoms. Vomiting was infrequently reported as a primary symptom, but of 11 military personnel in whom vomiting was a major symptom, 9 (82 percent) had serologic evidence of infection with the Norwalk virus. CONCLUSIONS: Gastroenteritis caused by enterotoxigenic E. coli and shigella resistant to a number of drugs was a major problem that frequently interfered with the duties of U.S. troops during Operation Desert Shield.

BACKGROUND: Most indications for whole blood transfusion are now well managed exclusively with blood component therapy, yet the use of fresh whole blood for resuscitating combat casualties has persisted in the U.S. military. METHODS: Published descriptions of whole blood use in military and civilian settings were compared with use of whole blood at the 31st Combat Support Hospital (31st CSH) stationed in Baghdad in 2004-2005. FINDINGS: Concerns about logistics, safety, and relative efficacy of whole blood versus component therapy have argued against the use of whole blood in most settings. However, military physicians have observed some distinct advantages in fresh warm whole blood over component therapy during the massive resuscitation of acidotic, hypothermic, and coagulopathic trauma patients. In this critical role, fresh whole blood was eventually incorporated as an adjunct into a novel whole-blood-based massive transfusion protocol. CONCLUSIONS: Under extreme and austere circumstances, the risk:benefit ratio of whole blood transfusion favors its use. Fresh whole blood may, at times, be advantageous even when conventional component therapy is available.

Patellar instability has been extensively studied in selected, high-risk cohorts, but the epidemiology in the general population remains unclear. A longitudinal, prospective epidemiological database was used to determine the incidence and demographic risk factors for patellar dislocations presenting to emergency departments of the United States. The National Electronic Injury Surveillance System was queried for all patellar dislocations presenting to emergency departments between 2003 and 2008. Incidence rate ratios (IRRs) were then calculated with respect to sex, age, and race. The hypothesis was that patellar dislocation is influenced by sex, age, race, and athletic participation. An estimated 40,544 patellar dislocations occurred among an at-risk population of 1,774,210,081 person-years for an incidence rate of 2.29 per 100,000 person-years in the United States. When compared with males, females showed no significant overall or age-stratified differences in the rates of patellar dislocation (IRR 0.85, 95% CI 0.71, 1.00; p = 0.08; p > 0.05). Peak incidence of patellar dislocation occurred between 15 and 19 years of age (11.19/100,000 person-years). When compared with Hispanic race, black and white race were associated with significantly higher rates of patellar dislocation (IRR 4.30 [95% CI 1.63, 6.97; p = 0.02], IRR 4.02 [95% CI 1.06, 6.98; p = 0.03], respectively). Nearly half (51.9%) of all patellar dislocation occurred during athletic activity, with basketball (18.2%), soccer (6.9%), and football (6.3%) associated with the highest percentage of patellar dislocation during athletics. Age between 15 and 19 years is associated with higher rates of patellar dislocation. Sex is not a significant risk factor for patellar dislocation. Black and white race are a significant risk factor for patellar dislocation when compared with Hispanic race. Half of all patellar dislocation occurs during athletic activity. This study was conducted on the Level of evidence II.

BACKGROUND: A prospective, longitudinal analysis of injuries sustained by a large combat-deployed maneuver unit has not been previously performed. METHODS: A detailed description of the combat casualty care statistics, distribution of wounds, and mechanisms of injury incurred by a U.S. Army Brigade Combat Team during "The Surge" phase of Operation Iraqi Freedom was performed using a centralized casualty database and an electronic medical record system. RESULTS: Among the 4,122 soldiers deployed, there were 500 combat wounds in 390 combat casualties. The combat casualty rate for the Brigade Combat Team was 75.7 per 1,000 soldier combat-years. The % killed in action (KIA) was 22.1%, and the %died of wounds was 3.2%. The distribution of these wounds was as follows: head/neck 36.2%, thorax 7.5%, abdomen 6.9%, and extremities 49.4%. The percentage of combat wounds showed a significant increase in the head/neck region (p < 0.0001) and a decrease in the extremities (p < 0.03) compared with data from World War II, Korea, and Vietnam. The percentage of thoracic wounds (p < 0.03) was significantly less than historical data from World War II and Vietnam. The %KIA was significantly greater in those soldiers injured by an explosion (26.3%) compared with those soldiers injured by a gunshot wound (4.6%; p = 0.003). Improvised explosive devices accounted for 77.7% of all combat wounds. CONCLUSIONS: There was a significantly higher proportion of head/neck wounds compared with previous U.S. conflicts. The 22.1% KIA was comparable with previous U.S. conflicts despite improvements in individual/vehicular body armor and is largely attributable to the lethality of improvised explosive devices. The lethality of a gunshot wound in Operation Iraqi Freedom has decreased to 4.6% with the use of individual body armor.

The United States forces in Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) are primarily engaged in counterinsurgency operations within an irregular war. The US combat medical experience has reported new injury patterns secondary to the enemy's reliance on explosive mechanisms, particularly improvised explosive devices (IEDs), and the widespread use of individual and vehicular body armor. Musculoskeletal extremity injuries have been reported to comprise approximately 50% of all combat wounds for OIF/OEF. Utilization of individual body armor has dramatically reduced thoracic injuries and has decreased the lethality of gunshot wounds, as measured by the percent killed in action, which in conflicts prior to OIF/OEF was estimated at 33% but is now 4.6%. Explosive mechanisms of injury, with IEDs being the most common, account for over 75% of all combat casualties. The lethality of IEDs coupled with the protection of the thorax and abdomen provided by individual body armor has resulted in increasingly severe orthopaedic injuries. Collection and careful examination of orthopaedic combat casualties will allow for improved military personnel protective measures and treatment of injured soldiers.

BACKGROUND: Little is known of the long-term results of acute arthroscopic Bankart repair for first-time traumatic anterior glenohumeral dislocations. HYPOTHESIS: Acute arthroscopic Bankart repair for first-time traumatic anterior glenohumeral dislocations will provide good results at long-term follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The authors evaluated a cohort of young patients who sustained first-time anterior glenohumeral dislocations and were acutely treated with arthroscopic Bankart repair using bioabsorbable tacks. Subjective outcome measures were obtained at a mean follow-up of 11.7 years (range, 9.1-13.9 years). RESULTS: Thirty-nine patients (40 shoulders) were available of the original cohort of 49 shoulders (82%). Two of the 9 who were lost to follow-up had revision surgery before being lost and are carried forward in the calculations of recurrent instability and revision surgery but are not included in the calculation of the functional scores. The mean Single Assessment Numeric Evaluation was 91.7, the mean Western Ontario Shoulder Instability score was 371.7, the mean subjective Rowe score was 25.3, the mean Simple Shoulder Test was 11.1, the mean American Shoulder and Elbow Society score was 90.9, the mean Short Form-36 Physical Component score was 94.4, and the mean Tegner score was 6.5. Six patients sustained recurrent dislocations for a redislocation rate of 14.3%. Nine patients (21.4%) reported experiencing subluxation events. Six patients (14.3%) underwent revision stabilization surgery. CONCLUSION: At long-term follow-up, acute arthroscopic Bankart repair for first-time traumatic anterior glenohumeral dislocations resulted in excellent subjective function and return to athletics in young, active patients with an acceptable rate of recurrence and reoperation.

BACKGROUND: Previous studies have shown that women involved in similar activities as men are at increased risk for anterior cruciate ligament injuries. HYPOTHESIS: The incidence rate of complete anterior cruciate ligament tears for men and women in our athletic, college-aged population is similar. STUDY DESIGN: Descriptive epidemiology study. METHODS: Students graduating in class years 1994 to 2003 at our institution who sustained complete anterior cruciate ligament tears were assessed for mechanism of injury and type of sport played at time of injury. We calculated the incidence proportion, an estimation of risk, by gender and class year, and the incidence proportion ratio comparing men and women by class year. We also calculated incidence rates by gender and type of sport played and incidence rate ratios comparing men and women. RESULTS: There were 353 anterior cruciate ligament injuries in the 10 classes studied. We found an overall, 4-year incidence proportion of 3.24 per 100 (95% confidence interval, 2.89-3.63) for men and 3.51 (95% confidence interval, 2.65-4.65) for women (incidence proportion ratio, 1.09 [95% confidence interval, 0.80-1.47]). The overall anterior cruciate ligament injury rate, excluding male-only sports, was significantly greater in women (incidence rate ratio, 1.51 [95% confidence interval, 1.03-2.21]). We found significantly greater injury rates among women in a gymnastics course (incidence rate ratio, 5.67 [95% confidence interval, 1.99-16.16]), indoor obstacle course test (incidence rate ratio, 3.72 [95% confidence interval, 1.25-11.10]), and basketball (incidence rate ratio, 2.42 [95% confidence interval, 1.05-5.59]). CONCLUSION: We found little gender difference in the overall risk of an anterior cruciate ligament tear; however, there were gender differences in injury rates when specific sports and activities were compared and when male-only sports were removed from the overall rate assessment.

Purpose The purpose of this paper is to investigate the use of medical‐grade polymethylmethacrylate (PMMA) in fused deposition modeling (FDM) to fabricate porous customized freeform structures for several applications including craniofacial reconstruction and orthopaedic spacers. It also aims to examine the effects of different fabrication conditions on porosity and mechanical properties of PMMA samples. Design/methodology/approach The building parameters and procedures to properly and consistently extrude PMMA filament in FDM for building 3D structures were determined. Two experiments were performed that examined the effects of different fabrication conditions, including tip wipe frequency, layer orientation, and air gap (AG) (or distance between filament edges) on the mechanical properties and porosity of the fabricated structures. The samples were characterized through optical micrographs, and measurements of weight and dimensions of the samples were used to calculate porosity. The yield strength, strain, and modulus of elasticity of the samples were determined through compressive testing. Findings Results show that both the tip wipe frequency (one wipe every layer or one wipe every ten layers) and layer orientation (transverse or axial with respect to the applied compressive load) used to fabricate the scaffolds have effects on the mechanical properties and resulting porosity. The samples fabricate in the transverse orientation with the high tip wipe frequency have a larger compressive strength and modulus than the lower tip wipe frequency samples (compressive strength: 16±0.97 vs 13±0.71 MPa, modulus: 370±14 vs 313±29 MPa, for the high vs low tip wipe frequency, respectively). Also, the samples fabricated in the transverse orientation have a larger compressive strength and modulus than the ones fabricated in the axial orientation (compressive strength: 16±0.97 vs 13±0.83 MPa, modulus: 370±14 vs 281±22 MPa; for samples fabricated with one tip wipe per layer in the transverse and axial orientations, respectively). In general, the stiffness and yield strength decreased when the porosity increased (compressive strength: 12±0.71 to 7±0.95 MPa, Modulus: 248±10 to 165±16 MPa, for samples with a porosity ranging from 55 to 70 percent). As a demonstration, FDM is successfully used to fabricate patient‐specific, 3D PMMA implants with varying densities, including cranial defect repair and femur models. Originality/value This paper demonstrates that customized, 3D, biocompatible PMMA structures with varying porosities can be designed and directly fabricated using FDM. By enabling the use of PMMA in FDM, medical implants such as custom craniofacial implants can be directly fabricated from medical imaging data improving the current state of PMMA use in medicine.

A number of theories regarding the aetiology of Crohn's disease have been proposed. Diet, infections, other unidentified environmental factors and immune disregulation, all working under the influence of a genetic predisposition, have been viewed with suspicion. Many now believe that Crohn's disease is a syndrome caused by several aetiologies. The two leading theories are the infectious and autoimmune theories. The leading infectious candidate is Mycobacterium avium subspecies paratuberculosis (Mycobacterium paratuberculosis), the causative agent of Johne's disease, an inflammatory bowel disease in a variety of mammals including cattle, sheep, deer, bison, monkeys and chimpanzees. The evidence to support M. paratuberculosis infection as a cause of Crohn's disease is mounting rapidly. Technical advances have allowed the identification and/or isolation of M. paratuberculosis from a significantly higher proportion of Crohn's disease tissues than from controls. These methodologies include: (i) improved culture techniques; (ii) development of M. paratuberculosis-specific polymerase chain reaction assays; (iii) development of a novel in situ hybridization method; (iv) efficacy of macrolide and anti-mycobacterial drug therapies; and (v) discovery of Crohn's disease-specific seroreactivity against two specific M. paratuberculosis recombinant antigens. The causal role for M. paratuberculosis in Crohn's disease and correlation of infection with specific stratification(s) of the disorder need to be investigated. The data implicating Crohn's as an autoimmune disorder may be viewed in a manner that supports the mycobacterial theory. The mycobacterial theory and the autoimmune theory are complementary; the first deals with the aetiology of the disorder, the second deals with its pathogenesis. Combined therapies directed against a mycobacterial aetiology and inflammation may be the optimal treatment of the disease.