Sustained Stress Fractures Research Articles

Glacial vis-à-vis tectono-provenance signals of the Plio-Pleistocene sediments of the intermontane Kashmir basin, northwestern Himalaya: Evidence from quartz micro-textures and a till deposit

The Himalayan-Tibetan orogen has a great influence on regional and global atmospheric circulation and, hence, it is important for understanding the dynamics of global environmental change. The Kashmir valley, located in the northwestern Himalaya, provides a unique sequence of continuous sedimentary records of unconsolidated sediments of more than a km thickness, dated back to 4 Ma. There are number of studies which suggest episodic and widespread cold conditions, including glaciations, within the Kashmir valley during the Plio-Pleistocene. In order to test the hypothesis of the glacial input into the Kashmir basin, scanning electron microscopy (SEM) was applied to analyze quartz grains of the Karewa deposits stratigraphically for the evidence of their sedimentary history. The microtextures indicate the dominant presence of sustained high stress fractures on the quartz grains with little effect of weathering and dissolution from 4 to 2.1 Ma and from 1.6 to 0.4 Ma. The quartz grains are also angular and of high relief. All these features suggest that these sediments are primarily transported by glaciers and melt water streams. However, the samples ranging in age from 2.1 to 1.7 show a mixed signal (glacial and fluvial) with a dominance of fluvial signal. This transition is attributed to the source area change from the Himalayan range (NE) to the Pir Panjal range (SW) because of the uplift along the Main Boundary Thrust (MBT). Furthermore, we report the first occurrence of a till deposit within the lower part (Dubjan Member 4–3.5 Ma) of the Karewa Group of the Kashmir basin which points to ice advancement in the northwestern Himalaya during the mid-Pliocene. Since, the till occurs in the upper part of the Dubjan Member, therefore, the timing of this glaciation can be restricted to be between 3.7 and 3.5 Ma. Hence, matches well with the mid-Pliocene glaciation that occurred in the Tibetan Plateau (~3.6 Ma) and other parts of the Northern Hemisphere (3.5 Ma).

SAT-385 A Normal FGF23 Does Not Preclude Tumor Induced Osteomalacia (TIO)

BACKGROUND: The phosphaturic, bone-derived hormone FGF23, mediates bone loss in TIO. Tumor resection typically results in skeletal healing and reversal of biochemical defects.Case: A 45-year-old Caucasian man with no past medical history presented with non-traumatic fractures of bilateral metatarsals. Over the subsequent 2 years, he sustained fragility stress fractures in bilateral femurs, eventually rendering him non-ambulatory; though he continued to work as a property manager in an office setting. History included 30 pack-years of smoking as well as osteochondrosarcoma in his mother. Labs showed a low phosphorus at 2.1 mg/dL [2.7–4.5], along with calcium 8.8 mg/dL [8.4–10.4], iPTH 48 pg/mL [12–88], and ALP of 155 [IU]/L [34–104]. 25-OH vitamin D and 1,25-(OH)2 vitamin D were 27 ng/mL [30–80] and 12 pg/mL [20–80], respectively. Free testosterone was 4.4 ng/mL [5–21] and LH 2.2 mIU/mL [3.0–10.0]. Other pituitary hormones and brain MRI were unremarkable.Vitamin D3, calcitriol, phosphate and testosterone were prescribed. Testosterone was discontinued 6 months later, after diagnosis with DVT/PE. Incidental rib fractures on CXR prompted a 3-phase 99Tc-MDP bone scan, revealing multiple sites of uptake: ribs, scapulae, sternum, thoracolumbar spine, sacrum, bilateral ankles and feet. DXA revealed T-scores of -2.8 in the spine and -1.9 in the femoral neck.Labs pointed to ongoing phosphate wasting, despite compliance with calcitriol 0.25 mcg, cholecalciferol 5000 IU and phosphorus 2250 mg in divided doses. Calculated TRP was 64% [>80%] and TmP/GFR 1.74 mg/dL [2.5–4.5], consistent with low phosphate reabsorption. Urine 24-hour calcium was 244.8 mg. Testing for causal mutations of hypophosphatemic rickets and osteogenesis imperfecta was negative. FGF23 was within the reference range at 138 RU/mL [LabCorp ELISA 44–215], interpreted as inappropriately normal given ongoing phosphate loss. This prompted a search for a suspected TIO locus.Two years after presentation, 18F-FDG-PET exhibited a hypermetabolic focus at the left suprapatellar recess. Biopsy was consistent with a mesenchymal tumor and chromogenic in situ hybridization (Mayo Clinic) was positive for FGF23 mRNA. After surgical resection of the 1.7 cm tumor, serum FGF23 declined to <50 RU/mL and was 90 RU/mL 3 weeks later [Mayo <180 RU/mL]. Calcitriol and phosphorus supplementation were discontinued. One year post-operatively phosphorus was 3.6 mg/dL [2.5–5.0], with a normal calcium, iPTH and 25-OH vitamin D. Lumbar spine T score improved to -1.0 (+46.43%).Conclusion: A high clinical index of suspicion is required for TIO in the setting of phosphaturic osteomalacia, particularly with a normal serum FGF23. Recently, similar microRNA profiles were noted in osteosarcomas and TIO1. This, along with our patient’s family history raises the question of a possible predisposition to skeletal neoplasms.1. Green et al. Bone Reports, 2017.

One-Barrel Microsurgical Fibula Flap for Reconstruction of Large Defects of the Femur.

Various methods for reconstructing large femur bone defects after tumor resection have been introduced. In this study, we reviewed the clinical outcomes of using a 1-barrel free vascularized fibular graft (FVFG) protected by a lateral locking plate for large femoral defects not involving the knee joint.Between August 2007 and August 2013, we treated 7 patients with large femoral bone defects after tumor resection. The mean age of the patients was 19 years (range, 12-36 years), and 3 were women. All defects were free of infection before the procedure. Femoral bone defects were reconstructed using a 1-barrel FVFG protected by a lateral locking plate. The mean bone defect size was 10.5 cm (range, 6-16 cm). We reviewed clinical outcomes at the last follow-up.All patients survived beyond the last follow-up; the mean follow-up period was 54 months (range, 26-100 months). Two patients sustained stress fractures of the FVFG, but the lateral locking plate protected the fractured graft until in situ bone healing obtained. Mean time to bone union of both host-graft junctions was 24 months (range, 18-31 months). The mean Musculoskeletal Tumor Society score (%) was 85.8% (range, 80-95%).A 1-barrel FVFG protected by a lateral locking plate maintained a stable graft-host bone construct, successfully leading to bone healing, even in cases of stress fractures of the graft, and appears to be a good option for large femur bone defects.

Expected Time to Return to Athletic Participation After Stress Fracture in Division I Collegiate Athletes.

Background:Few studies have documented expected time to return to athletic participation after stress fractures in elite athletes.Hypothesis:Time to return to athletic participation after stress fractures would vary by site and severity of stress fracture.Study Design:Retrospective cohort study.Level of Evidence:Level 3.Methods:All stress fractures diagnosed in a single Division I collegiate men’s and women’s track and field/cross-country team were recorded over a 3-year period. Site and severity of injury were graded based on Kaeding-Miller classification system for stress fractures. Time to return to full unrestricted athletic participation was recorded for each athlete and correlated with patient sex and site and severity grade of injury.Results:Fifty-seven stress fractures were diagnosed in 38 athletes (mean age, 20.48 years; range, 18-23 years). Ten athletes sustained recurrent or multiple stress fractures. Thirty-seven injuries occurred in women and 20 in men. Thirty-three stress fractures occurred in the tibia, 10 occurred in the second through fourth metatarsals, 3 occurred in the fifth metatarsal, 6 in the tarsal bones (2 navicular), 2 in the femur, and 5 in the pelvis. There were 31 grade II stress fractures, 11 grade III stress fractures, and 2 grade V stress fractures (in the same patient). Mean time to return to unrestricted sport participation was 12.9 ± 5.2 weeks (range, 6-27 weeks). No significant differences in time to return were noted based on injury location or whether stress fracture was grade II or III.Conclusion:The expected time to return to full unrestricted athletic participation after diagnosis of a stress fracture is 12 to 13 weeks for all injury sites.Clinical Relevance:Athletes with grade V (nonunion) stress fractures may require more time to return to sport.

The effect of stress fracture interventions in a single elite infantry training unit (1983–2015)

Stress fractures can be seen as an undesired byproduct of demanding physical training. The threshold value of stress that places an individual bone at high risk for stress fracture has not been identified. In a prospective study of stress fractures in 1983, a 31% incidence was found during demanding Israeli infantry basic training by bone scan criteria. Within a subgroup of these recruits, an elite infantry unit was found to have a 40% incidence. Since then and until 2015, eight additional induction companies of the same elite infantry unit were prospectively monitored for stress fractures during their basic training. In all of the studies, stress fracture surveillance and the examining orthopedist were the same.A retrospective review of all nine studies and of eight training changes was performed to look for a temporal trend in stress fracture incidence and to see if these might be related to training changes. There was a statistically significant trend for lower radiological proven stress fractures (p=0.0001) and radiological proven stress fractures plus clinical stress fractures (p=0.0013), as well as lower stress fracture severity by radiological criteria (p=0.0001) between 1983 and 2015.The only training change that was associated, by multivariate logistic regression, with a decreased incidence of stress fracture was restricting training to the authorized training protocol (odds ratio, 3874; 95% CI, 1.526 to 9.931; p=0.004). Increased recruit weight was found by multivariate analysis to be associated with lower stress fracture incidence (odds ratio 1.034; 95% CI, 1.00 to 1.070; p=0.051). Moving the training to a base with flatter terrain and reducing the formal marching distance by 1/3 was associated with a decrease in high grade stress fractures (odds ratio, 10.03; 95% CI, 3.5 to 28.4; p=0.0001). Neither the combined changes of enforcing a seven hour a night sleep regimen, training in more comfortable boots and adding a physical therapist to the unit nor stopping specific running exercises and adding lower body strengthening exercises were associated with a decrease in stress fracture. 67% of recruits who sustained stress fractures and 69% who did not sustain stress fracture finished their military service as combat soldiers in the unit (p=0.87).There are no magic bullets to prevent stress fractures. Stress cannot be lowered beyond the level which compromises the training goals. It is a problem that can be managed by awareness that identifies and treats stress fractures while they are still in the micro stage and not in the more dangerous macro stage.

INJURIES IN ELITE AUSTRALIAN FEMALE CRICKETERS

BackgroundCricket Australia has a well-established injury surveillance program for its elite male players and has published regular reports. Whilst injury data has been collected for the elite female players, it...

Free Vascularized Fibular Graft With LISS Plate for the Bone Defects of the Femur After Tumor Resection

Background: Various methods for reconstructing large femur bone defects after tumor resection have been introduced. In this study, we reviewed the clinical outcomes of using a one-barrel free vascularized fibular graft (FVFG) protected by a less invasive stabilization system (LISS) plate for lesions not involving the joint. Methods: Between August 2007 and August 2013, we treated 7 patients with large femoral bone defects after tumor resection. The mean age of the patients was 19 years (range, 12-36 years), and 3 were women. All were diagnosed preoperatively with osteosarcoma. Femoral bone defects were reconstructed using an in-lay strut FVFG following a LISS femoral plate. The mean bone defect size was 10.5 cm (range, 6-16 cm). We reviewed clinical outcomes at the last follow-up. Result: All patients survived beyond the last follow-up; the mean follow-up period was 54 months (range, 26-100 months). Two patients (28.5%) sustained stress fractures of the FVFG, but the LISS plate protected the fractured graft until in situ bone healing occurred. One case of metal failure of the LISS plate was encountered; the plate was replaced with a longer one, which achieved bone union. Mean time to bone union of both host-graft junctions was 24 months (range, 18-31 months). The mean Musculoskeletal Tumor Society score (%) was 85.8% (range, 80-95%). Conclusion: A one-barrel FVFG protected by a LISS plate maintained a stable graft-host bone construct, successfully leading to bone union, even in cases of stress fractures of the graft, and appears to be a good option for large femur bone defects after tumor resection.

The effect of high versus low loading on bone strength in middle life

While bone mass and geometry are largely genetically determined, mechanical loading is considered to be an important additional determinant. This study investigates to what extent very high mechanical loading begun at a young age and sustained afterward can affect tibia bone mass and geometry in middle age. Cohorts from a common ethnic background, with a history of very high and very low tibia bone loading based on an assessment of their activities according their strain levels were compared. The study hypothesis was that the tibia bone density and geometric strength parameters would be greater in the high bone loading cohort.Subjects from a group of elite infantry recruits who sustained a 31% incidence of stress fractures during their basic training in 1983, were reviewed 25years later. The tibia bone strength of 25 of these soldiers, 11 of whom had sustained stress fractures, was compared to a group of 20 subjects who received exemption from military service in 1982–5 because they were religious scholars and who continued these studies afterwards. Anthropometric measurements were made. The bone density and geometric strength of the tibia was assessed by quantitative computerized tomography (QCT). The average daily dietary intake and metabolic expenditure of subjects were assessed by questionnaires.At the 25year follow-up soldiers were on an average 3cm taller than the religious scholars (p=0.02) and had lower abdominal girths (p=0.03). There was no difference in the tibia cortical density between cohorts in spite of the fact that the religious scholars had lower daily calcium intakes (p=0.02). Soldiers had stronger tibias based on geometric engineering criteria. The mean area moments of inertia (p=0.02, p=0.04) and polar moments of inertia (p=0.02) were 16% larger in the soldier cohort. By multivariate regression analysis greater height, weight and daily energy expenditure were related to larger bone geometric strength parameters. According to semipartial eta-square analysis, between 39% to 45% of the variance in the area moments of inertia between the cohorts was attributable to these three parameters. The religious scholars burned less calories daily, principally because they did no sport activity (p=0.001). There was no difference in tibia bone strength parameters between soldiers who did and did not sustain stress fractures in their 1983 basic training.In conclusion, in a middle age population with a common ethnic origin, the high bone loading cohort had stronger tibias than the low bone loading cohort based on larger geometric strength properties and not because of higher cortical density. In spite of being at the extremes of the bone loading spectra, the tibia area moment of inertia of the two cohorts in this study differed by only 16%, with part of this difference attributable to factors other than bone loading. We do not know for sure if the difference in the geometric properties is related to high bone loading or whether people with stronger bones are more likely to engage in high bone loading. Healthy male subjects who sustained stress fractures at a young age do not have weaker tibias at middle age according to QCT measurements.

Analysis of stress fractures in athletes based on our clinical experience

To analyze stress fractures in athletes based on experience from our sports medicine clinic. We investigated the association between stress fractures and age, sex, sports level, sports activity, and skeletal site in athletes seen at our sports medicine clinic between September 1991 and April 2009. Stress fractures of the pars interarticularis were excluded from this analysis. During this period (18 years and 8 mo), 14276 patients (9215 males and 5061 females) consulted our clinic because of sports-related injuries, and 263 patients (1.8%) [171 males (1.9%) and 92 females (1.8%)] sustained stress fractures. The average age of the patients with stress fractures was 20.2 years (range 10-46 years); 112 patients (42.6%) were 15-19 years of age and 90 (34.2%) were 20-24 years of age. Altogether, 90 patients (34.2%) were active at a high recreational level and 173 (65.8%) at a competitive level. The highest proportion of stress fractures was seen in basketball athletes (21.3%), followed by baseball (13.7%), track and field (11.4%), rowing (9.5%), soccer (8.4%), aerobics (5.3%), and classical ballet (4.9%). The most common sites of stress fractures in these patients were the tibia (44.1%), followed by the rib (14.1%), metatarsal bone (12.9%), ulnar olecranon (8.7%) and pelvis (8.4%). The sites of the stress fractures varied from sport to sport. The ulnar olecranon was the most common stress fracture site in baseball players, and the rib was the most common in rowers. Basketball and classical ballet athletes predominantly sustained stress fractures of the tibia and metatarsal bone. Track and field and soccer athletes predominantly sustained stress fractures of the tibia and pubic bone. Aerobics athletes predominantly sustained stress fractures of the tibia. Middle and long distance female runners who sustained multiple stress fractures had the female athlete triad. The results of this analysis showed that stress fractures were seen in high-level young athletes, with similar proportions for males and females, and that particular sports were associated with specific sites for stress fractures. Middle and long distance female runners who suffered from multiple stress fractures had the female athlete triad.

Stress fractures in elite male football players

The objective was to investigate the incidence, type and distribution of stress fractures in professional male football players. Fifty-four football teams, comprising 2379 players, were followed prospectively for 189 team seasons during the years 2001-2009. Team medical staff recorded individual player exposure and time-loss injuries. The first team squads of 24 clubs selected by UEFA as belonging to the 50 best European teams, 15 teams of the Swedish Super League and 15 teams playing their home matches on artificial turf pitches were included. In total, 51 stress fractures occurred during 1,180,000 h of exposure, giving an injury incidence of 0.04 injuries/1000 h. A team of 25 players can therefore expect one stress fracture every third season. All fractures affected the lower extremities and 78% the fifth metatarsal bone. Stress fractures to the fifth metatarsal bone, tibia or pelvis caused absences of 3-5 months. Twenty-nine percent of the stress fractures were re-injuries. Players that sustained stress fractures were significantly younger than those that did not. Stress fractures are rare in men's professional football but cause long absences. Younger age and intensive pre-season training appear to be risk factors.

Stress fracture of the hamate body and fourth metacarpal base following military style push-ups: an unusual trauma mechanism

We report the case of a 19-year-old male soldier, who sustained stress fractures of the hamate body and fourth metacarpal base due to his daily knuckle push-up routine in the military. We introduce repetitive microtrauma due to daily knuckle push-ups as an unusual, but potential trauma mechanism for metacarpal and carpal stress fractures.

Kinetic asymmetry in female runners with and without retrospective tibial stress fractures

Gait asymmetry may be linked to the tendency for runners to sustain chronic overuse injuries. This paper compares gait asymmetry in female runners who have never sustained a running-related injury to those who have sustained unilateral tibial stress fractures. The symmetry index was used to characterize asymmetry in the kinetics of both subject groups. There were three aims to this study: (1) to report natural levels of asymmetry for healthy, never-injured female runners, (2) to compare asymmetry levels between never-injured runners and those who have sustained stress fractures, and (3) to examine the kinetics between the involved and uninvolved limbs of runners who have sustained stress fractures. In all three aims, peak medial, lateral, braking, vertical impact, and vertical ground reaction forces, average and peak instantaneous vertical loading rates, and peak shock were examined. In the never-injured runner group, natural levels of asymmetry ranged from 3.1% for peak vertical ground reaction force up to 49.8% for peak lateral ground reaction force. Symmetry indices were not significantly different in the runners who had previously sustained stress fractures. The involved limb of the previously injured runners demonstrated higher values for braking and vertical impact ground reaction force and peak shock. Interestingly, these runners appeared to have bilaterally-elevated lateral ground reaction forces and loading rates as compared to the never-injured group, although this was not statistically tested. This suggests that previously injured runners may be closer to the injury threshold and, thus, more susceptible. Asymmetry may simply influence the side on which they become injured.

Stress fractures in athletes: review of 196 cases

The purpose of this study was to investigate theassociation of stress fractures with age, sex, sport level,sporting activity, and skeletal site in athletes seen at oursports medicine clinic between September 1991 and May 2001.During these 10 years, 10 726 patients (6415 males, 3861females) visited our clinic because of sport-related injuries,and 196 patients [125 males (1.9%), 71 females (1.8%)]sustained stress fractures. The average age of the patients withstress fractures was 20.1 years (range 10–46 years); 84 patients(42.6%) were 15–19 years of age, and 68 (34.7%) were 20–24years of age. Altogether, 74 patients (37.8%) were active atthe high recreational level and 122 (62.2%) at the competitivelevel. The sites of the stress fractures varied from sport tosport. The ulnar olecranon was the most common stressfracture site among baseball athletes and the rib among therowing athletes. Classical ballet, aerobics, tennis, and volleyballathletes predominantly sustained stress fractures of thetibial shaft. Basketball athletes predominantly sustained stressfractures of the tibial shaft and medial malleolus and themetatarsal bone, whereas track and field and soccer athletespredominantly sustained stress fractures of the tibial shaftand pubic bone. Our results show that stress fractures areseen even in high-level adolescent athletes, with similarproportions for males and females, and that particular sportsare associated with specific sites for stress fractures.

Stress Fractures

To review the cases of stress fracture seen over a 2-year period at a sports medicine clinic. One hundred and eighty cases diagnosed as stress fractures on the basis of clinical picture and radiological evidence were reviewed. The following features of each stress fracture were noted: age, sex, site, sport/activity. A sports medicine centre in Melbourne, Australia. The average age was 21.8 years. Seventy eight of these stress fractures were seen in women, 102 in men. The most common sites of stress fractures were the metatarsal bones (n = 42), tibia (n = 36), fibula (n = 30), tarsal navicular (n = 26) and pars interarticularis (n = 17). The most common sport was track (n = 54). Other common sports activities were jogging/distance running (n = 35), dance (n = 32) and Australian football (n = 14). The distribution of sites of stress fractures varied from sport to sport. Among the track athletes (n = 54), navicular (n = 19), tibia (n = 14) and metatarsal (n = 9) were the most common stress fracture sites. The distance runners (n = 35) predominantly sustained tibia (n = 15), and fibula (n = 8) stress fractures, while metatarsal stress fractures (n = 18) were the most common among dancers. The distribution of sports varied with the site of the stress fracture. In the metatarsal stress fractures (n = 42), dance was the most common activity. Distance running (n = 15) and track (n = 14) were the most common sports in the group to have sustained tibia stress fractures (n = 36). Track athletes (n = 14) were particularly prevalent in the navicular stress fracture group (n = 26). The distribution of sites of stress fractures in this study shows some differences from previously published studies.

Stress Fractures of Bone in Conscripted Infantry Recruits: Lack of Correlation to Pre-Army Physical Fitness

The occurrence of stress fractures (SF) in 1,118 Israeli conscripted infantry recruits and their relation to the pre-army physical fitness as estimated from the results of a competitive field run were studied prospectively. About 8.5% of recruits sustained scintigraphy-proven SF during their basic training. The pre-army physical fitness of recruits who sustained SF was not significantly different from that of recruits who did not. Tibial SF accounted for 57% of the total, metatarsal for 22.4%, and femoral for 17.9%. Other anatomical locations were rare. Twenty-eight of 35 (80%) femoral SF were asymptomatic. There were no cases of displaced SF at any site. Only one recruit had to discontinue training because of SF. Our data suggest that diminished pre-army physical fitness does not predispose recruits to SF, and that most scintigraphy-defined SF in conscripted infantry recruits are benign.

多発性の疲労骨折を生じた一卵性双生児例

We reported a case of 16-year-old monozygotic twins who had multiple stress fractures for one and half year after they participated in rugby football club. One of the twins sustained stress fractures at the middle third of the left tibia and the upper third and middle third of the left fibula. The other had at the upper third of the left fibula, and the second and third right metatarsals.In addition, we did questionnaire for 144 high school rugby football players to clarify the causes of stress fracture in athletes. The causes seem to have relation to the method and time of the trainings, no holiday a week, and individual anatomical features.

Recurrent stress fractures in military recruits. One-year follow-up of 66 recruits.

Of 66 recruits who sustained stress fractures during basic training and returned to training after a period of rest, seven (10.6%) suffered recurrent fractures within one year. None of the recurrences was at the original anatomical site. All of the recruits with recurrent stress fractures had had at least one of their initial stress fractures in the femur. This suggests that a femoral stress fracture carries a high risk of recurrence at other sites.

The lon g -term followup of soldiers with stress fractures

A group of 295 Israeli infantry recruits was evaluated in a prospective study of stress fractures which began in basic training. On the basis of scintigraphy, 91 of the recruits (31%) were found to have sustained stress fractures during basic training. Sixty-six of the 91 recruits with stress fractures (72%) were followed for a minimum of 1 year after basic training to determine the natural history of a soldier who sustains a stress fracture and resumes training after a period of rest. Five clinical patterns were observed: (1) uneventful recovery (47%); (2) protracted recovery (13.6%); (3) symptoms consistent with recurrent stress fractures in new sites (19.6%); (4) intermittent nonstress fracture bone pain (16.7%); and (5) chronic stress fractures (3%). The incidence of recurrent stress fractures was 10.6%. A control group of 60 recruits who sustained no stress fractures in basic training had a 1.7% incidence of stress fractures after basic training. Recruits who sustained stress fractures in basic training continued to be a higher risk for stress fractures during subsequent training.

Stress Fractures in 51 Runners

A prospective study was initiated in 1976 to investigate runners who are at risk for incurring stress fractures and how these fractures can be prevented. Fifty-one runners incurred 57 stress fractures. Tibial fractures were most common (25), followed by fibula (12) and metatarsal (8). Seven runners had previously sustained stress fractures, and six developed two stress fractures simultaneously. Five women over 30 years old had pelvic stress fractures. Stress fracture development was positively correlated with the presence of pes planus, weekly training distances greater than 20 miles, hard training surfaces, and training regimen modifications. The incidence did not correlate with generalized musculoskeletal laxity or tightness. Forty-four of 51 patients had initially positive roentgenograms. Five of five bone scans were positive. The average duration of rest before running was resumed was 7.4 weeks.