Previous Stress Fracture Research Articles

Examining the Relationship between Exercise Dependence, Disordered Eating, and Low Energy Availability.

Both dietary and exercise behaviors need to be considered when examining underlying causes of low energy availability (LEA). The study assessed if exercise dependence is independently related to the risk of LEA with consideration of disordered eating and athlete calibre. Via survey response, female (n = 642) and male (n = 257) athletes were categorized by risk of: disordered eating, exercise dependence, disordered eating and exercise dependence, or if not presenting with disordered eating or exercise dependence as controls. Compared to female controls, the likelihood of being at risk of LEA was 2.5 times for female athletes with disordered eating and >5.5 times with combined disordered eating and exercise dependence. Male athletes with disordered eating, with or without exercise dependence, were more likely to report signs and symptoms compared to male controls-including suppression of morning erections (OR = 3.4; p < 0.0001), increased gas and bloating (OR = 4.0–5.2; p < 0.002) and were more likely to report a previous bone stress fracture (OR = 2.4; p = 0.01) and ≥22 missed training days due to overload injuries (OR = 5.7; p = 0.02). For both males and females, in the absence of disordered eating, athletes with exercise dependence were not at an increased risk of LEA or associated health outcomes. Compared to recreational athletes, female and male international caliber and male national calibre athletes were less likely to be classified with disordered eating.

Analysis of Fracture Patterns and Characteristics in Sacral Insufficiency Fracture: Do Sacral Fractures Occur in Patients Who Had Previous Lumbosacral Fusion Insufficiency Fractures or Stress Fractures?

Study DesignThis study is a retrospective analysis of a case.PurposeThe purpose of this study is to investigate the fracture patterns and risk factors of sacral insufficiency fractures (SIFs) to improve their diagnosis in clinical practice.Overview of LiteratureSIFs occur when normal stresses are applied to a bone with decreased density, most often due to osteoporosis. Individuals who receive lumbosacral fusion procedures may also suffer from increased incidents of SIFs because of decreased bone density related to aging.MethodsIn total, 55 patients with SIFs were retrospectively investigated in this study. The study population was divided into lumbosacral fusion (n=20) and non-fusion (n=35) groups. Subsequently, the patients’ demographic characteristics, comorbidities, medication history, results of diagnostic imaging studies, and bone mineral density were assessed. The fracture patterns were classified either according to the five typical types (H-pattern bilateral vertical plus horizontal component, unilateral vertical only, bilateral vertical only, unilateral vertical plus horizontal component, and horizontal only fracture) or atypical types.ResultsIn total, 44 of 55 patients (80%) suffered from more than one senile disease and received corresponding medications that caused secondary osteoporosis. A total of 12 patients had S1 lumbosacral fixation. Moreover, three of these 12 patients who developed a SIF immediately after a lumbosacral fracture had an unstable sacral U fracture. The remaining nine patients showed fracture patterns similar to the non-fusion patients. Single-photon emission computed tomography (SPECT)/computed tomography (CT) can identify fracture recurrence in previously healed fractures. In total, 24 patients (43.6%) had fractures of the pelvis, femur, and thoracolumbar spine.ConclusionsSIF develops in elderly patients with multiple adult diseases that can induce secondary osteoporosis. Such fractures may occur in the patients with instrumented lumbosacral fusion. Importantly, some patients showed stress fractures after multilevel instrumented lumbosacral fusion, whereas others showed insufficiency fractures. The different fracture patterns correspond to different grades of SIF, and SPECT/CT can easily identify the fracture status.

Prospective Evaluation of Vitamin D Levels and Stress Injury in Collegiate Female Long-Distance Runners

Category:Lesser Toes, Midfoot/Forefoot, SportsIntroduction/Purpose:The incidence of stress injury in female runners is reported in up to 21% of competitive runners, with female runners at higher risk for stress injury than men. Bone metabolism is closely linked with vitamin D, which may play a role in the high prevalence of stress fractures in female runners. Although runners who train outdoors in the southeastern US have adequate vitamin D levels, no study to date has evaluated runners in northeastern US. The aim of the study was to prospectively evaluate the relationship between 25-OH vitamin D serum levels and the incidence of stress injury in a cohort of collegiate competitive long-distance runners.Methods:101 female collegiate runners from 7 Northeastern US colleges competing in varsity cross country were enrolled. Surveys were collected from all the study participants at the start of the fall cross country season reviewing demographics, weekly mileage, and medical history, including previous stress fracture incidence. Additionally, baseline (“summer”) serum 25-hydroxy vitamin D levels were obtained. Subjects insufficient in vitamin D (<30ng/mL) were supplemented with cholecalciferol (D3) 50,000 units weekly for 8 weeks and 2,000 units daily for an additional 1 month. In subjects with vitamin D insufficiency, repeat labs were performed at 3 months and repeat surveys distributed. To account for variation in season and geographical location, all subjects underwent repeat vitamin D labs at 6 months (”winter”). Fisher’s exact test was used to determine whether vitamin D levels were correlated with incidence of stress fracture.Results:91/101 (90%) subjects with mean BMI of 20.5 and average age of 20 years completed all study requirements. The mean summer and winter vitamin D serum levels were 64.0 ng/mL (SD 16.6; range 28.9-112.9) and 45.0 ng/mL (SD 13.8; range 20.1- 90.6), respectively. One subject (1%) in the summer and 9 subjects (10%) in the winter were supplemented for vitamin D insufficiency. 7/10 (70%) insufficient subjects and 28/81 (35%) vitamin D sufficient subjects reported a stress fracture during the study period. Patients that had an insufficient vitamin D result were significantly more likely to have a stress fracture during the study period (p=0.041; Table 1). The mean change in vitamin D level from summer to winter was -19.7 (SD 14.4; range -60.5- 60.7).Conclusion:The high rate of stress fractures in this cohort of collegiate female long-distance runners is greater than previously reported. Runners who are vitamin D insufficient are at a higher risk to incur a stress fracture. The results of the study also highlight the considerable seasonal variance in vitamin D levels amongst female collegiate long-distance runners in the northeastern US. Further study is needed to determine whether vitamin D supplementation reduces the risk of stress fractures.

Prevalence of Indicators of Low Energy Availability in Elite Female Sprinters.

Low energy availability (LEA), and subsequent relative energy deficiency in sport, has been observed in endurance, aesthetic, and team sport athletes, with limited data on prevalence in athletes in short-burst activities such as sprinting. We examined prevalence of signs and symptoms of LEA in elite female sprinters at the start of the training season (PRE), and at the end of a 5-month indoor training period (POST). Four of 13 female sprinters (31%) presented at PRE testing with at least one primary (amenorrhea, low bone mineral density, low follicle-stimulating hormone, luteinizing hormone, or estradiol, resting metabolic rate ≤29kcal/kg fat-free mass, Low Energy Availability in Females Questionnaire score ≥8) and one secondary indicator of LEA (fasting blood glucose <4mmol/L, free triiodothyronine <3.5pmol/L, ferritin <25μg/L, low-density lipoprotein cholesterol >3.0mmol/L, fasting insulin <20pmol/L, low insulin-like growth factor-1, systolic blood pressure <90mmHg, and/or diastolic blood pressure <60mmHg). At POST, seven out of 13 athletes (54%) presented with at least one primary and one secondary indicator of LEA, three of whom had also presented with indicators of LEA at PRE. Five out of 13 (39%) athletes had previous stress fracture history, though this was not associated with current indicators of LEA (PRE: r = .52, p = .07; POST: r = -.07, p = .82). In conclusion, elite female sprinters may present with signs and symptoms of LEA, even after off-season rest. Medical and coaching staff should be aware of the signs and symptoms of LEA and relative energy deficiency in sport and should include appropriate screening and intervention strategies when working with sprinters.

Predisposing Risk Factors for Stress Fractures in Collegiate Cross-Country Runners.

Giffin, KL, Knight, KB, Bass, MA, and Valliant, MW. Predisposing risk factors and stress fractures in collegiate cross-country runners. J Strength Cond Res 35(1): 227-232, 2021-The purpose of this study was to explore factors associated with increased stress fractures in collegiate cross-country runners. Subjects in this study were 42 male and female cross-country runners at a Division I university. Each athlete completed a questionnaire regarding smoking status, vitamin/mineral intake, previous stress fracture history, birth control usage, menstrual status, and demographic information. Nutritional assessment using a 3-day food record and measurements of whole body, lumbar spine, and hip bone mineral densities (BMDs) were also conducted on each athlete. Results indicated that 40% of the female and 35% of the male runners reported a history of stress fracture, and that all of them did not meet the recommended daily energy intake or adequate intakes for calcium or vitamin D required for their amount of training. Two-tailed t-test found statistically higher incidences of lumbar spine BMD in male and female runners whose daily calcium and vitamin D intakes were below minimum requirements as well as for women whose caloric intake was below the required level. When data on the lumbar spine was evaluated, 31% of subjects (31.8% of the male and 30% of the female runners) were identified as having osteopenia and 4.8% with osteoporosis. Results warrant a need for future longitudinal studies.

Navicular Stress Fracture Outcomes in Athletes: Analysis of 62 Injuries

The optimal treatment modalities for navicular stress fractures in athletes is currently unknown for this season-ending injury. The present study evaluated factors that might be significant and affect healing outcomes, specifically focusing on the return to activity (RTA) time and a decreased desired activity (DDA) after treatment in athletes. Such considerations included previous navicular stress fractures, patient demographic data and type of sport, and initiation time of treatment. The data from 59 patients with 62 fractures were prospectively analyzed from May 2005 through July 2016. The results showed a significant correlation between a previous navicular stress fracture and decreased desired activity. The average duration of symptoms before receiving definitive treatment was 8.8 months. Computed tomography as the initial imaging modality correlated positively with a correct diagnosis (1.00). In contrast, magnetic resonance imaging, when used initially, was only 71% accurate. Runners constituted most of the cohort at 38 (61.3%). Ten other athletes were involved in jumping sports. Of the 62 injuries, 21 (33.9%) were in elite or professional athletes, all of whom were able to RTA, with 1 patient, a 38-year-old world record holding runner, having a DDA. Seven refractures (11.2%) occurred an average >5 years after the initial injury, predominantly in those aged <21 years, none with previous surgery. Eight patients (12.9%) developed postinjury arthrosis, including 1 with DDA. Patients who underwent open reduction and internal fixation had a RTA of 4.56 months compared with those who had undergone nonoperative treatment, who had an average RTA of 3.97 months. Seven patients (11.2%) underwent screw removal and required a longer RTA. Overall, of the 62 injuries, the patients with 57 of the injuries (91.9%) were able to RTA at their preinjury level.

Stress fracture and premenstrual syndrome in Japanese adolescent athletes: a cross-sectional study

ObjectivesTo investigate the relationship between the occurrence of stress fracture and premenstrual syndrome (PMS)/premenstrual dysphoric disorder (PMDD) in Japanese adolescent athletes.DesignCross-sectional study.SettingOsaka, Japan.ParticipantsA school-based survey on menstruation and school life...

Female Recreational Exercisers at Risk for Low Energy Availability.

Low energy availability (LEA) describes the disruption in normal physiological function existent when insufficient energy intake is combined with exercise. To conserve energy a range of endocrine adaptations occur, impairing health and athletic performance. The prevalence of LEA has not been fully established especially among recreational exercisers. Determining recreational exercisers at risk of LEA may help to maximize prevention, early diagnosis and treatment. The design of this study was a cross-sectional online survey. One-hundred and nine female recreational exercisers, with a mean age of 23.8 (SD 6.9) years were recruited via gyms and fitness centers throughout NZ. Participants completed an online questionnaire including questions from the LEAF-Q (Low Energy Availability in Females Questionnaire). A total of 45.0% (CI, 35.4%, 54.8%) of participants were classified as "at risk" of LEA. For every extra hour of exercise per week the odds of being at risk of LEA were 1.13 times greater (CI 1.02, 1.25, p = .016). All participants reporting previous stress fracture injuries (n = 4) were classified as at risk for LEA. Significantly more subjects participating in an individual sport were classified as at risk for LEA (69.6%, CI 24.3%, 54.8%) compared with team sports (34.8%, CI 18.7%, 40.5%) (p = .006). The high prevalence of female recreational exercisers at risk of LEA is of concern, emphasizing the importance of increasing awareness of the issue, and promoting prevention and early detection strategies, so treatment can be implemented before health is severely compromised.

Comparison of Femoral Neck Stress Fractures in Pediatric versus Young Adult Athletes

Objectives:To compare the demographics, metabolic bone health, radiologic features, treatment approaches and recurrence rates of pediatric versus young adult athletes with femoral neck stress fractures.Methods:A retrospective review was performed on all patients <45 years-old who were diagnosed with a femoral neck stress fracture at a single tertiary-care referral center from 2003-2015. Patients who had undergone previous hip surgery or had primary bone disorders/lesions were excluded. Variables analyzed included demographics, presenting symptoms, metabolic bone health (laboratory results, Dexa scores, menstrual history, eating disorder history), imaging, treatment approach and clinical course.Results:Forty-nine patients (mean age 21.4 years, range 5-44, 78% females) met study inclusion criteria, including 28 pediatric patients (mean age 14.4 years, range 5-19 years, 71% females) and 21 young adults (mean age 30.8 years, range 20-44 years, 86% females). A higher percentage of females was seen with each increasing decade of age, with 50% of pediatric patients under 11 years-old being male. Mean BMI was lower (p=0.04) in the pediatric group (20.6 kg/m2 +/-3.42) than the adult group (21.8 kg/m2 +/-2.04). Pain was the presenting complaint in all patients, with pain localized to the groin in 80% of cases. Participation in running sports was higher for the young adult cohort (86%) than the pediatric cohort (50%), while multiple sports were played more by pediatric patients (29%) than young adults (5%). History of previous acute fractures (2%) and previous stress fractures (14%) was identical between groups. Delayed menarche was recorded in 6% of pediatric patients, and menstrual irregularity was reported in 29% and 33% of pediatric and adult females, respectively. The base of the femoral neck was most common location for fracture in both pediatric (67%) and adult (81%) groups, while transcervical fractures were more likely to occur in pediatric (29%) than adult patients (6%). More significant treatment interventions were pursued in the pediatric group (spica casting: n=2, operative screw fixation, n=4) than the adult group, all of whom demonstrated healing with activity modification, with varying degrees of weight bearing protection and medical optimization of metabolic bone health. There was no difference in the mean time to healing (13.3 weeks), or in the mean time to return to sports (Peds: 16wks, Adults: 13wks) between groups. There was a significant correlation between time to RTS and the extent of the femoral neck edema (p=0.048).Conclusion:Pediatric caregivers should be aware of femoral neck stress fractures in young athletes, an entity historically described almost exclusively in adults. Stress fractures in pediatric and adolescent patients are more likely to occur higher on the neck than adult patients, and both sexes in children may be affected to a greater degree than in adult counterparts, in whom females are affected much more commonly. Groin pain and participation in running sports are common in both groups, while multi-sport pediatric athlete patients may be more likely to be affected than in the adult population. More significant treatment interventions may be warranted in children. To avoid the catastrophic sequella of a displaced femoral neck fracture, proactive diagnostic workup and consideration of interventions such as spica casting or surgical screw fixation should be exercised given concerns related to non-compliance in this population.

Women with previous stress fractures show reduced bone material strength

Background and purpose — Bone fragility is determined by bone mass, bone architecture, and the material properties of bone. Microindentation has been introduced as a measurement method that reflects bone material properties. The pathogenesis of underlying stress fractures, in particular the role of impaired bone material properties, is still poorly understood. Based on the hypothesis that impaired bone material strength might play a role in the development of stress fractures, we used microindentation in patients with stress fractures and in controls.Patients and methods — We measured bone material strength index (BMSi) by microindentation in 30 women with previous stress fractures and in 30 normal controls. Bone mineral density by DXA and levels of the bone markers C-terminal cross-linking telopeptide of type-1 collagen (CTX) and N-terminal propeptide of type-1 procollagen (P1NP) were also determined.Results — Mean BMSi in stress fracture patients was significantly lower than in the controls (SD 72 (8.7) vs. 77 (7.2); p = 0.02). The fracture subjects also had a significantly lower mean bone mineral density (BMD) than the controls (0.9 (0.02) vs. 1.0 (0.06); p = 0.03). Bone turnover—as reflected in serum levels of the bone marker CTX—was similar in both groups, while P1NP levels were significantly higher in the women with stress fractures (55 μg/L vs. 42 μg/L; p = 0.03). There was no correlation between BMSi and BMD or bone turnover.Interpretation — BMSi was inferior in patients with previous stress fracture, but was unrelated to BMD and bone turnover. The lower values of BMSi in patients with previous stress fracture combined with a lower BMD may contribute to the increased propensity to develop stress fractures in these patients.

Plantar Loading During Cutting While Wearing a Rigid Carbon Fiber Insert.

Context : Stress fractures are one of the most common injuries in sports, accounting for approximately 10% of all overuse injuries. Treatment of fifth metatarsal stress fractures involves both surgical and nonsurgical interventions. Fifth metatarsal stress fractures are difficult to treat because of the risks of delayed union, nonunion, and recurrent injuries. Most of these injuries occur during agility tasks, such as those performed in soccer, basketball, and lacrosse. Objective : To examine the effect of a rigid carbon graphite footplate on plantar loading during 2 agility tasks. Design : Crossover study. Setting : Laboratory. Patients or Other Participants : A total of 19 recreational male athletes with no history of lower extremity injury in the past 6 months and no previous metatarsal stress fractures were tested. Main Outcome Measure(s) : Seven 45° side-cut and crossover-cut tasks were completed in a shoe with or without a full-length rigid carbon plate. Testing order between the shoe conditions and the 2 cutting tasks was randomized. Plantar-loading data were recorded using instrumented insoles. Peak pressure, maximum force, force-time integral, and contact area beneath the total foot, the medial and lateral midfoot, and the medial, middle, and lateral forefoot were analyzed. A series of paired t tests was used to examine differences between the footwear conditions (carbon graphite footplate, shod) for both cutting tasks independently (α = .05). Results : During the side-cut task, the footplate increased total foot and lateral midfoot peak pressures while decreasing contact area and lateral midfoot force-time integral. During the crossover-cut task, the footplate increased total foot and lateral midfoot peak pressure and lateral forefoot force-time integral while decreasing total and lateral forefoot contact area. Conclusions : Although a rigid carbon graphite footplate altered some aspects of the plantar- pressure profile during cutting in uninjured participants, it was ineffective in reducing plantar loading beneath the fifth metatarsal.

Tibial Stress Fractures in an Active Duty Population: Long-Term Outcomes

Tibial stress fractures are a common overuse injury among military recruits. The purpose of this study was to determine what, if any, long-term effects that tibial stress fractures have on military personnel with respect to physical activity level, completion of military training, recurrence of symptoms, and active duty service. Twenty-six military recruits included in a previous tibial stress fracture study were contacted 10 years after initial injury and asked a series of questions related to any long-term consequences of their tibial stress fracture. Of the 13 patients available for contact, no patients reported any necessary limited duty while on active duty, and no patient reported being separated or discharged from the military as a result of stress fracture. Tibial stress fractures in military recruits are most often an isolated injury and do not affect ability to complete military training or reflect a long-term need for decreased physical activity.

Bilateral Foot Pain - Former Runner

HISTORY: A 26-year-old female presents for evaluation of chronic bilateral foot pain. The pain began one year ago in her left foot with no clear preceding event. She was initially evaluated at an outside hospital, and MRI revealed possible stress fracture of the 2nd and 3rd metatarsal heads versus 2nd and 3rd digit tendinopathy of the flexor hallucis longus and digitorum longus and brevis. Her left foot was placed in a CAM walker for 1-2 months, but she had no resolution of her symptoms. Over the past two months, she began having pain in her right foot. Pain was initially located on the dorsum of her left foot, but now is primarily on bilateral plantar aspects. It is made worse by walking in high heels, but improved with tennis shoes. She previously lost 20 kg with diet and running before she stopped running 2 years ago. Her menses have been normal. She denies any previous stress fracture, fracture, osteoporosis, or eating disorder. Her medical history is significant for depression and anxiety for which she takes citalopram. PHYSICAL EXAMINATION: Ht 5'10", Wt 152 lbs, BMI 22. Bilateral hindfoot valgus and pes planus. Normal foot and ankle range of motion. Tenderness to palpation on plantar aspect of 2nd - 4th metatarsals bilaterally. Squeeze test was painful but did not cause radiation, numbness, or tingling in her toes. Gait is slightly antalgic. DIFFERENTIAL DIAGNOSIS: 1. Bilateral metatarsal stress fracture 2. Freiburg's disease 3. Morton's neuroma 4. Chronic Tendinitis 5. Rheumatologic disorder 6. Hyperparathyroidism TEST AND RESULTS: Comprehensive metabolic panel, TSH, vitamin D level, and bilateral 3-view of feet normal. MRI of bilateral feet: -Marked marrow edema of left 2nd -3rd and right 5th metatarsal heads. Small to moderate amount of fluid within the right 1st intermetatarsal space. Effusion within the left 2nd MTP joint. There is large surrounding joint effusion and intraarticular heterogeneous curvilinear low signal, likely representing robust synovitis within the right 2nd and 3rd MTP joints. -Subsequent ESR, CRP, CBC, and ANA profile normal -Rheumatoid factor 90 IU/ml (positive) -Anti-CCP > 200 U/ml (positive) FINAL WORKING DIAGNOSIS: Atypical rheumatoid arthritis of forefeet TREATMENT AND OUTCOMES: Referred to rheumatologyTreated with Diclofenac and prednisone with great improvement in symptoms

Effect of Carbon Graphite Foot Plate on Loading During Jumping and Landing

Fifth metatarsal stress fractures have a high incidence of non-union, delayed union, and re-fracture independent of post-injury treatment. After screw fixation for the treatment of 5th metatarsal stress fractures, many patients are being treated with a rigid carbon graphite foot plate (CFP) to decrease plantar loading. PURPOSE: To determine if total foot, lateral midfoot (LMF) and lateral forefoot (LFF) loading (peak pressure, contact area, and force-time integral) were decreased with the use of the CFP. METHODS: Plantar loading in 13 healthy male, collegiate, recreational athletes was evaluated using the Pedar-X in-shoe system collecting at 100Hz (Novel, St. Paul, MN, USA). Exclusion criteria were any history of lower extremity injuries in the past six months, foot or ankle surgery within the past 3 years, and previous metatarsal stress fractures. Prior to data collection all subjects signed informed consent. Subjects completed 7 simulated lay-ups in a standard running shoe with and without a CFP. In order to complete the task properly, subjects needed to jump and land on the same foot, which was the foot used for analysis. A 2×2 repeated measures ANOVA was used to compare the take-off (TO) and landing (LD) both with and without the CFP (a=0.05). RESULTS: The subjects had an average height of 1.76 ± 0.08 m, mass of 73.38 ± 9.87 kg, and age of 21.6 ± 2.75 years. The total foot maximum force was significantly greater during landing when compared with the take-off (p=0.012). No other significant differences existed between these two tasks. Independent of the task, the total foot contact area was significantly decreased in the CFP condition (p<0.001), while the total foot peak pressure was increased with the CFP (p<0.001). LMF Contact area was decreased (p=0.016) when wearing the CFP. No differences in the force-time integral were found in the LMF or LFF. Peak pressure was increased in the LMF (p<0.001), and LFF (p=0.002) when wearing the CFP. CONCLUSIONS: In this initial study, the results indicate that the CFP is ineffective at reducing plantar loading beneath the 5th metatarsal during jumping and landing in uninjured controls. However, CFP needs to be examined to determine its role in other sporting maneuvers and footwear in patients with a 5th metatarsal fracture history.

Distinct Hip and Rearfoot Kinematics in Female Runners With a History of Tibial Stress Fracture

Cross-sectional controlled laboratory study. To investigate the kinematics of the hip, knee, and rearfoot in the frontal and transverse planes in female distance runners with a history of tibial stress fracture. Tibial stress fractures are a common overuse injury in runners, accounting for up to half of all stress fractures. Abnormal kinematics of the lower extremity may contribute to abnormal musculoskeletal load distributions, leading to an increased risk of stress fractures. Thirty female runners with a history of tibial stress fracture were compared to 30 age-matched and weekly-running-distance-matched control subjects with no previous lower extremity bony injuries. Kinematic and kinetic data were collected using a motion capture system and a force platform, respectively, as subjects ran in the laboratory. Selected variables of interest were compared between the groups using a multivariate analysis of variance (MANOVA). Peak hip adduction and peak rearfoot eversion angles were greater in the stress fracture group compared to the control group. Peak knee adduction and knee internal rotation angles and all joint angles at impact peak were similar between the groups. Runners with a previous tibial stress fracture exhibited greater peak hip adduction and rearfoot eversion angles during the stance phase of running compared to healthy controls. A consequence of these mechanics may be altered load distribution within the lower extremity, predisposing individuals to stress fracture.

Plantar Loading Comparisons between Women with a History of Second Metatarsal Stress Fractures and Normal Controls

Background Stress fractures are common in athletics and are more prevalent in women. The current literature has not identified a reason for this gender difference. Hypothesis Women with a history of a second/third metatarsal stress fracture will demonstrate differences in loading in the middle forefoot. Study Design Controlled laboratory study. Methods Fifteen men, 15 control women, and 9 women with a history of a second/third metatarsal stress fracture were asked to run at 3.3 m/s ± 5% along a 10-m runway. Plantar loading parameters were recorded using a Pedar-X system. Results The women with fractures demonstrated a decrease in contact area and maximum force beneath the middle forefoot when compared with the female controls. Men demonstrated a decreased contact area in the medial and middle forefoot when compared with the control women. In addition, the women with fractures had decreased maximum force in the middle forefoot when compared with the control women. Conclusions The decrease in maximum force in the middle forefoot in patients with a previous stress fracture could have resulted from gait alterations after the fracture. Therefore, prospective studies need to be completed to better understand the loading differences that could be used to predict stress-fracture injury risk. Clinical Relevance It is unclear whether plantar loading can be used as a predictor of stress-fracture injury risk as these patients were tested after a stress fracture.

Risk Factors for Stress Fracture among Young Female Cross-Country Runners

To identify risk factors for stress fracture among young female distance runners. Participants were 127 competitive female distance runners, aged 18-26, who provided at least some follow-up data in a randomized trial among 150 runners of the effects of oral contraceptives on bone health. After completing a baseline questionnaire and undergoing bone densitometry, they were followed an average of 1.85 yr. Eighteen participants had at least one stress fracture during follow-up. Baseline characteristics associated (P<0.10) in multivariate analysis with stress fracture occurrence were one or more previous stress fractures (rate ratio [RR] [95% confidence interval]=6.42 (1.80-22.87), lower whole-body bone mineral content (RR=2.70 [1.26-5.88] per 1-SD [293.2 g] decrease), younger chronologic age (RR=1.42 [1.05-1.92] per 1-yr decrease), lower dietary calcium intake (RR=1.11 [0.98-1.25] per 100-mg decrease), and younger age at menarche (RR=1.92 [1.15-3.23] per 1-yr decrease). Although not statistically significant, a history of irregular menstrual periods was also associated with increased risk (RR=3.41 [0.69-16.91]). Training-related factors did not affect risk. The results of this and other studies indicate that risk factors for stress fracture among young female runners include previous stress fractures, lower bone mass, and, although not statistically significant in this study, menstrual irregularity. More study is needed of the associations between stress fracture and age, calcium intake, and age at menarche. Given the importance of stress fractures to runners, identifying preventive measures is of high priority.

Are knee mechanics during early stance related to tibial stress fracture in runners?

Tibial stress fractures are a serious overuse injury in runners. Greater vertical loading rates and tibial shock have been found in runners with previous tibial stress fracture compared to controls. The timing of these variables occurs very early in the stance phase and suggests that conditions shortly after footstrike may be important in determining injury risk. The purpose of this study was to further investigate lower extremity mechanics in early stance in runners with a history of tibial stress fracture. In addition, the relationships between these variables were explored. Twenty-three runners with a history of tibial stress fracture were investigated. They were compared with 23 age and mileage matched control subjects with no previous lower extremity bony injuries. Data were collected as subjects ran at 3.7 m/s. All variables of interest were computed over the period from footstrike to the impact peak of the vertical ground reaction force. Independent t-tests and effect sizes were used to assess the differences between the groups. Pearson Product Moment correlations were used to determine whether initial stance variables were related to tibial shock in the two groups. Sagittal plane knee stiffness was significantly greater in the tibial stress fracture group. Stiffness was also positively correlated with shock. Knee excursion, knee angle at footstrike and shank angle at footstrike were not different between groups. These findings provide further support for the relationship between mechanics during initial loading and tibial stress fractures in runners. This relationship may be important in terms of retraining gait to reduce the risk of stress fracture in runners.

Are Initial Contact Conditions Related to Tibial Stress Fracture in Distance Runners?

Runners with previous tibial stress fracture (TSF) have higher peak tibial shock (TSHK) and vertical loading rates than runners with no bony injuries. These events occur just after foot strike, before the body can respond to surface conditions. Therefore, different initial lower extremity compliance and leg angle may lead to differences in shock and loading rates which might be important in relation to TSF. PURPOSE: To determine whether runners with previous TSF contact the ground with a stiffer lower extremity. That is, with a more flexed knee (KFLEX) and a more vertical leg (ALEG) at foot contact, plus a stiff er knee (KSTIF) and less flexion excursion (KEXC) from foot strike to impact peak than runners with no injury. A further purpose is to determine whether these variables are correlated with TSHK. METHODS: Healthy runners who had sustained a TSF previously (RTSF; n = 20) and an age and mileage matched control group with no previous lower extremity bony injury (CTRL; n = 20) provided informed consent and participated. Gait data were collected at 120 Hz (960 Hz analog) as subjects ran at 3.7m/s on a 25m runway. Data from five trials were averaged for analysis. Independent t-tests and effect size (ES) were used to investigate the hypothesized differences between the groups. Pearson Product Moment correlations were used to determine whether initial contact variables were related to TSHK. RESUITS: (Angles in degrees, stiffness is change in normalized joint moment (Nm/ (mass in kg x height in m)) divided by change in joint angle)TableRunners with previous TSF (and, therefore, higher TSHK) have higher KSTIF at initial contact than controls. Furthermore, KSTIF was moderately correlated with TSHK across the sample. Small effects with moderate correlations for KEXC and ALEG suggest that pose of the leg during initial contact is less important. CONCLUSION: Knee stiffness is greater in runners with previous TSF, but the pose of the leg is not statistically different from controls. Prospective studies are needed to determine whether KSTIF is high prior to TSF.

Comparison of static and dynamic biomechanical measures in military recruits with and without a history of third metatarsal stress fracture

For Royal Marine recruits in training, the third metatarsal is the most common site for stress fracture. Previous evidence regarding biomechanical factors contributing to metatarsal stress fracture development is conflicting, possibly due to the lack of differentiation between the metatarsals. The present retrospective study compares static anatomical characteristics and dynamic biomechanical variables for Royal Marine recruits with and without a history of third metatarsal stress fracture. Ten Royal Marine recruits with a history of third metatarsal stress fracture were compared with control subjects with no previous stress fracture occurrence. Selected static anatomical variables were measured to describe the ankle and subtalar joints. Peak ankle dorsi-flexion and rearfoot eversion were measured during running. In addition, peak vertical and horizontal ground reaction force variables were compared for the two study groups. No significant differences in static anatomical variables were identified between study groups. During running, peak rearfoot eversion was found to occur significantly earlier for the stress fracture group than for their matched controls, suggesting an increase in time spent loading the forefoot. The peak applied resultant horizontal force during the braking phase was directed significantly more laterally for the stress fracture group. In addition, the peak magnitude of resultant horizontal force applied during the propulsion phase was significantly lower for the stress fracture subjects. The findings of this study highlight the importance of including dynamic biomechanical data when exploring variables associated with the development of third metatarsal stress fracture and indicate that successful interventions to reduce the incidence of this injury are likely to focus on forefoot function during braking and propulsion.