Stress fractures in elite male football players

Risk factors of metatarsal stress fracture associated with repetitive sports activities: a systematic review

Background

Metatarsal stress fracture is common in people engaged in repetitive weight-bearing activities, especially athletes and recruits. Identifying risk factors in these contexts is crucial for effective prevention.

Methods

A systematic search on Web of Science, PubMed, EBSCO, SPORTDiscus, MEDLINE, and Cochrane Library was conducted and the date range for the retrieval was set from January 1984 to April 2024.

Results

32 eligible studies were selected from 1,728 related research. Anatomical and biomechanical factors, such as higher foot arch, abnormal inversion/eversion of foot, and longer metatarsal length or larger angles, relatively influence stress fracture risk. However, given that there is no standardized measurement, the results remain to be examined. Soccer is associated with fifth metatarsal fractures, while long-distance running and recruit training often lead to fractures of the second or third metatarsals. High exercise intensity, non-adaptive training, and inadequate equipment heighten fracture risk.

Conclusion

This review highlights the complex interplay of anatomical, biomechanical, and sports-related factors in the risk of metatarsal stress fractures. Relatively, high arches, specific metatarsal morphologies, and foot inversion/eversion patterns are significant risk factors, particularly among athletes. Sports type also correlates with metatarsal stress fracture locations. Despite extensive research, study heterogeneity and inherent biases necessitate cautious interpretation. Comprehensive, multifactorial approaches and personalized injury prevention strategies are essential for reducing the incidence of these injuries and improving the health and performance of athletes.

Awareness of fifth metatarsal stress fractures among soccer coaches in Japan: A cross-sectional study

Although a fifth metatarsal stress fracture is the most frequent stress fracture in soccer players, awareness of fifth metatarsal stress fractures among soccer coaches is unclear. Therefore, we performed an online survey of soccer coaches affiliated with the Japan Football Association to assess their awareness of fifth metatarsal stress fractures. A total of 150 soccer coaches were invited for an original online survey. Data on participants' age, sex, types of coaching licence, coaching category, types of training surface, awareness of fifth metatarsal stress fractures, and measures employed to prevent fifth metatarsal stress fractures were collected using the survey. Data from 117 coaches were analysed. Eighty-seven of the 117 coaches were aware of fifth metatarsal stress fractures; however, only 30% reported awareness of preventive and treatment measures for fifth metatarsal stress fractures. Licensed coaches (i.e., licensed higher than level C) were also more likely to be aware of fifth metatarsal stress fractures than unlicensed coaches were. Furthermore, although playing on artificial turf is an established risk factor for numerous sports injuries, soccer coaches who usually trained on artificial turf were more likely to be unaware of the risks associated with fifth metatarsal stress fractures than coaches who trained on other surfaces were (e.g., clay fields). Soccer coaches in the study population were generally aware of fifth metatarsal stress fractures; however, most were unaware of specific treatment or preventive training strategies for fifth metatarsal stress fractures. Additionally, coaches who practised on artificial turf were not well educated on fifth metatarsal stress fractures. Our findings suggest the need for increased awareness of fifth metatarsal stress fractures and improved education of soccer coaches regarding injury prevention strategies.　.

Shockwave Treatment vs Surgery for Proximal Fifth Metatarsal Stress Fractures in Soccer Players: A Pilot Study

BACKGROUND

To compare the clinical, radiologic, and functional outcomes between shockwave and operative treatments for proximal fifth metatarsal stress fractures in soccer players in a pilot study.

METHODS

Between 2017 and 2019, 18 soccer players with fifth metatarsal stress fractures attended at Mutualidad de Futbolistas Españoles-Delegación Catalana were included. Patients were randomly assigned into 2 groups receiving either surgery with an intramedullary screw (group 1) or high-energy focused extracorporeal shockwave treatment (group 2 performed once a week for 3 weeks using 2000 impulses at an energy flux density of 0.21 mJ/mm2 and 4 Hz frequency). Clinical (pain), radiologic (bone healing), and functional (Tegner Activity Scale and American Orthopaedic Foot & Ankle Society [AOFAS] ankle-hindfoot scales) outcomes before and after receiving the treatment were compared between both groups. In addition, ability and time to return to play was also compared between groups.

RESULTS

No patients were lost to follow-up. There were no statistically significant differences at last follow-up between surgery and extracorporeal shockwave treatment for bone healing, pain relief, AOFAS ankle-hindfoot score, Tegner score, and time return to play. No complications were reported in either of the 2 groups.

CONCLUSION

In this pilot study, extracorporeal shockwave treatment and operative treatment were found to be equally effective at reducing pain, achieving bone healing, and allowing the soccer players to return to play after proximal fifth metatarsal stress fractures. This study suggests that ESWT may be a good option for the management of proximal fifth metatarsal stress fractures in soccer players. If this approach proves successful in larger trials, the shockwave approach might help avoid known complications of the surgical treatment like wound problems, nerve injury, and hardware intolerance. Further investigations with larger sample size should be conducted in order to confirm the present conclusions.

LEVEL OF EVIDENCE

Level II, therapeutic, pilot randomized controlled trial.

Incidence of football injuries sustained on artificial turf compared to grass and other playing surfaces: a systematic review and meta-analysis

Background

Prior reviews have not conducted statistical synthesis of injury incidence on artificial turf in football. To analyse and compare the incidence of injuries sustained playing football (soccer) on artificial turf compared to grass and other playing surfaces.

Methods

This was a systematic review and meta-analysis. We searched PubMed, Scopus, SPORTDiscus, and Web of Science databases in October 2022 without filters. All observational studies (prospective or retrospective) that analysed injuries sustained playing football on artificial turf and which included a control group that played on grass or other surface were included. Studies were included if they reported the number of injuries and the exposure time for the playing surfaces. Risk of bias was assessed by Newcastle-Ottawa Scale. A random effects model was used to calculate the pooled incidence rate ratios (IRR) with 95% confidence intervals. Protocol was registered with PROSPERO on October 30th, 2022. Registration number: CRD42022371414.

Findings

We screened 1447 studies, and evaluated 67 full reports, and finally included 22 studies. Risk of bias was a notable issue, as only 5 of the 22 studies adjusted their analysis for potential confounders. Men (11 studies: IRR 0.82, CI 0.72-0.94) and women (5 studies: IRR 0.83, CI 0.76-0.91) had lower injury incidence on artificial turf. Professional players had a lower incidence of injury (8 studies: IRR 0.79, CI 0.70-0.90) on artificial turf, whereas there was no evidence of differences in the incidence of injury in amateur players (8 studies: IRR 0.91, CI 0.77-1.09). The incidence of pelvis/thigh (10 studies: IRR 0.72, CI 0.57-0.90), and knee injuries (14 studies: IRR 0.77, CI 0.64-0.92) were lower on artificial turf.

Interpretation

The overall incidence of football injuries is lower on artificial turf than on grass. Based on these findings, the risk of injury can't be used as an argument against artificial turf when considering the optimal playing surface for football.

Funding

No specific funding was received for this study.

Return to sport following low-risk and high-risk bone stress injuries: a systematic review and meta-analysis

OBJECTIVE

Bone stress injuries (BSIs) are classified in clinical practice as being at low- or high-risk for complication based on the injury location. However, this dichotomous approach has not been sufficiently validated. The purpose of this systematic review was to examine the prognostic role of injury location on return-to-sport (RTS) and treatment complications after BSI of the lower extremity and pelvis.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Web of Science, Cochrane CENTRAL and Google Scholar databases were searched from database inception to December 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Peer-reviewed studies that reported site-specific RTS of BSIs in athletes.

RESULTS

Seventy-six studies reporting on 2974 BSIs were included. Sixteen studies compared multiple injury sites, and most of these studies (n=11) described the anatomical site of injury as being prognostic for RTS or the rate of treatment complication. Pooled data revealed the longest time to RTS for BSIs of the tarsal navicular (127 days; 95% CI 102 to 151 days) and femoral neck (107 days; 95% CI 79 to 135 days) and shortest duration of time for BSIs of the posteromedial tibial shaft (44 days, 95% CI 27 to 61 days) and fibula (56 days; 95% CI 13 to 100 days). Overall, more than 90% of athletes successfully returned to sport. Treatment complication rate was highest in BSIs of the femoral neck, tarsal navicular, anterior tibial shaft and fifth metatarsal; and lowest in the fibula, pubic bone and posteromedial tibial shaft.

CONCLUSION

This systematic review supports that the anatomical site of BSIs influences RTS timelines and the risk of complication. BSIs of the femoral neck, anterior tibial shaft and tarsal navicular are associated with increased rates of complications and more challenging RTS.

PROSPERO REGISTRATION NUMBER

CRD42021232351.

Injury Burden in Professional European Football (Soccer): Systematic Review, Meta-Analysis, and Economic Considerations

OBJECTIVE

We performed a systematic review and meta-analysis to evaluate the injury burden and the related economic cost in European professional male football players.

DATA SOURCES

Multiple database research was performed up to August 5, 2022 (PubMed, EMbase, Scopus, Cochrane Library), including only studies that reported severity in the number of days of absence for each injury, incidence reported in the number of injuries/1000 hours, or reported number of injuries and exposure time and adult male football players, professionals from European clubs. Two reviewers extracted data and assessed paper quality with the Strengthening the Reporting of Observational Studies in Epidemiology statement and the Newcastle-Ottawa Scale.

MAIN RESULTS

Twenty-two studies have reported incidence, severity, and burden of injuries in professional football. The highest injury burden was found for ligament-joint injuries (37.9 days/1000 hours; 222 397 €/1000 hours) and for muscle injuries (34.7 days/1000 hours; 203 620 €/1000 hours). Injury locations with high burden were knee injuries (34.8 days/1000 hours; 20 4206 €/1000 hours)-mainly anterior cruciate ligament injuries (14.4 days/1000 hours; 84 499 €/1000 h)-followed by thigh injuries (25.0 days/1000 hours; 146 700 €/1000 hours), hamstrings injuries (15.4 days/1000 hours; 90 367 €/1000 hours), hip-and-groin injuries (16.1 days/1000 hours; 94 475 €/1000 hours), primarily adductor muscles injuries (9.4 days/1000 hours; 55 159€/1000 hours), and ankle injuries (13.1 days/1000 h; 76 871 €/1000 hours) with ankle sprains (7.4 days/1000 hours; 43 423 €/1000 hours).

CONCLUSIONS

Being exposed to injury risk has serious consequences for individual and club performance and economy. This review identified the most relevant targets in injury management, compared their injury data with reference values, and provided economic evidence when trying to gain buy-in from the key decision makers.

Genetic Variants within NOGGIN, COL1A1, COL5A1, and IGF2 are Associated with Musculoskeletal Injuries in Elite Male Australian Football League Players: A Preliminary Study

INTRODUCTION

Australian Football is a dynamic team sport that requires many athletic traits to succeed. Due to this combination of traits, as well as technical skill and physicality, there are many types of injuries that could occur. Injuries are not only a hindrance to the individual player, but to the team as a whole. Many strength and conditioning personnel strive to minimise injuries to players to accomplish team success.

PURPOSE

To investigate whether selected polymorphisms have an association with injury occurrence in elite male Australian Football players.

METHODS

Using DNA obtained from 46 elite male players, we investigated the associations of injury-related polymorphisms across multiple genes (ACTN3, CCL2, COL1A1, COL5A1, COL12A1, EMILIN1, IGF2, NOGGIN, SMAD6) with injury incidence, severity, type (contact and non-contact), and tissue (muscle, bone, tendon, ligament) over 7 years in one Australian Football League team.

RESULTS

A significant association was observed between the rs1372857 variant in NOGGIN (p = 0.023) and the number of total muscle injuries, with carriers of the GG genotype having a higher estimated number of injuries, and moderate, or combined moderate and high severity rated total muscle injuries. The COL5A1 rs12722TT genotype also had a significant association (p = 0.028) with the number of total muscle injuries. The COL5A1 variant also had a significant association with contact bone injuries (p = 0.030), with a significant association being found with moderate rated injuries. The IGF2 rs3213221-CC variant was significantly associated with a higher estimated number of contact tendon injuries per game (p = 0.028), while a higher estimated number of total ligament (p = 0.019) and non-contact ligament (p = 0.002) injuries per game were significantly associated with carriage of the COL1A1 rs1800012-TT genotype.

CONCLUSIONS

Our preliminary study is the first to examine associations between genetic variants and injury in Australian Football. NOGGIN rs1372857-GG, COL5A1 rs12722-TT, IGF2 rs3213221-CC, and COL1A1 rs1800012-TT genotypes held various associations with muscle-, bone-, tendon- and ligament-related injuries of differing severities. To further increase our understanding of these, and other, genetic variant associations with injury, competition-wide AFL studies that use more players and a larger array of gene candidates is essential.

Modelling Changes in Bone and Body Composition Over a Season in Elite Male Footballers

This study investigated the change in bone and body composition characteristics of elite football players and recreationally active control participants across the course of a season. Fortysix participants (20 footballers and 26 recreationally active controls) were assessed by dual-energy x-ray absorptiometry and peripheral Quantitative Computed Tomography for a range of bone and body composition characteristics at four points over the course of a competitive season. Multilevel modelling was used to examine changes. Footballers had higher characteristics than controls for 24 out of 29 dual-energy x-ray absorptiometry and peripheral Quantitative Computed Tomography variables (all p<0.05). However, there was also significant random inter-individual variation in baseline values for all variables, for both footballers and controls (p < 0.05). Wholebody bone mineral density, leg and whole-body bone mineral content, tibial bone mass and area (38%) increased across the season in footballers (p < 0.05), and there was significant random inter-individual variation in the rate of increase of leg and whole-body bone mineral content (p<0.05). Whole-body bone mineral density, leg and whole-body bone mineral content, tibial bone mass and area (38%) increased over the course of the season in elite football players. The modelling information on expected changes in bone characteristics provides practitioners with a method of identifying those with abnormal bone response to football training and match-play.

Does Magnetic Resonance Imaging Grading Correlate With Return to Sports After Bone Stress Injuries? A Systematic Review and Meta-analysis

BACKGROUND

While some studies have failed to reveal any significant relationship between magnetic resonance imaging (MRI) grading and return to sports after bone stress injuries, others have reported either a linear or nonlinear relationship.

PURPOSE

To evaluate the prognostic value of MRI grading for time to return to sports and rate of return to sports after bone stress injuries.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic search was performed in PubMed, Web of Science, SPORTDiscus, and Google Scholar. Studies reporting return to sports data after bone stress injuries using MRI grading systems were included in this review. The risk of bias was evaluated using the Quality in Prognosis Studies tool. Meta-analyses were performed to summarize the mean time to return to sports. The Pearson correlation was used to determine the relationship between time to return to sports and MRI grade. A meta-analysis of proportions was conducted to determine the percentage of athletes who successfully returned to sports.

RESULTS

A total of 16 studies with 560 bone stress injuries met inclusion criteria. Higher MRI-based grading was associated with an increased time to return to sports (P < .00001). Pooled data revealed that higher MRI-based grading correlated with a longer time to return to sports (r = 0.554; P = .001). Combining all anatomic locations, the mean time to return to sports was 41.7 days (95% CI, 30.6-52.9), 70.1 days (95% CI, 46.9-93.3), 84.3 days (95% CI, 59.6-109.1), and 98.5 days (95% CI, 85.5-112.6) for grade 1, 2, 3, and 4 injuries, respectively. Trabecular-rich sites of injury (eg, pelvis, femoral neck, and calcaneus) took longer to heal than cortical-rich sites of injury (eg, tibia, metatarsal, and other long-bone sites of injury). Overall, more than 90% of all athletes successfully returned to sports.

CONCLUSION

The findings from this systematic review indicate that MRI grading may offer a prognostic value for time to return to sports after the nonsurgical treatment of bone stress injuries. Both MRI grade and location of injury suggest that individually adapted rehabilitation regimens and therapeutic decisions are required to optimize healing and a safe return to sports.

Uncommon Bone Injuries in Soccer Players

Soccer is the most common team sport in the world. A significant number of players are associated with a large number of injuries. Injuries occur in a variety of contexts regardless of the age or performance level of players. The vast majority of injuries involve soft tissues. Bone injuries are less common, but usually result in long-term exclusion from the game. Three different types of fractures related to soccer are classified as acute types, stress fractures and avulsion. This manuscript outlines the diagnostic procedures and treatments for stress fractures, avulsion fractures and bone cyst. The common feature of the described injuries includes frequent difficulties associated with the correct diagnosis and treatment direction. In therapeutic treatment, the doctor and the patient often have to choose between conservative treatment and surgical treatment, which in many cases is not simple. We suggest that in the event of injuries to soccer players, surgical treatment should be used, shortening the time to return to full sports activity. A very important element of the therapeutic process is proper rehabilitation, which should be individually tailored to the patient in order to optimize the treatment process. Some of the rehabilitation protocols should be permanently incorporated into the warm-up protocols for training. Such a procedure has a preventive effect.

Traumatic Leg Fractures in UEFA Football Athletes: A Matched-Cohort Analysis of Return to Play, Reinjury, Player Retention, and Performance Outcomes

Background:

The average professional soccer team experiences 1 to 2 traumatic leg fractures per season, with unknown effects on player performance.

Purpose:

To (1) determine the rate and time to return to play (RTP) following leg fracture, (2) investigate the rate of reinjury following RTP, and (3) investigate long-term effects that lower extremity (LE) fracture may have on elite soccer player performance.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Using publicly available records, we identified athletes sustaining a traumatic leg fracture across the 5 major European soccer leagues (English Premier League, Bundesliga, La Liga, Ligue 1, and Serie A) between 2000 and 2016. Athletes with leg fracture (femur, tibia, and/or fibula) were matched 1:2 to controls by demographic characteristics and performance metrics 1 season before the index timepoint. Investigations included the RTP rate, reinjury rate, player characteristics associated with RTP within 2 seasons, long-term player retention, performance metrics during the 4 following seasons, and subgroup analysis by player position.

Results:

A total of 112 players with LE fracture and 224 controls were identified. Players with LE fractures were absent for a mean of 157 days (range, 24-601 days) and 21 games (range, 2-68 games). The rate of RTP within 1 season was 80%, with 4% experiencing subsequent refracture. Injured players remained active in the league at a higher rate than their uninjured counterparts. As compared with controls, injured athletes played 309 fewer total minutes (P < .05), scored 0.09 more assists per game (P < .01) 1 season after injury, and scored 0.12 more points per game 4 seasons after injury (P < .01). Defenders were most affected by an LE fracture, playing 5.24 fewer games (P < .05), 603 fewer total minutes (P < .01), and recording 0.19 more assists per 90 minutes of play as compared with controls 1 season after injury (P < .001). Attackers and midfielders demonstrated no significant difference in metrics after RTP when compared with controls.

Conclusion:

Most players sustaining an LE fracture returned to elite soccer at the same level after a significant loss of playing time, with a 4% rate of refracture. Player retention was higher for those sustaining an LE fracture versus uninjured controls. Overall, injured players did not experience a decline in performance after recovery from an LE fracture.

Lower-limb injury in elite Australian football: A narrative review of kinanthropometric and physical risk factors

OBJECTIVE

This review aims to provide a succinct and critical analysis of the current physical and mechanical demands of elite Australian football while examining lower-limb injury and the associated physical and kinanthropometric risk factors.

METHODS

MEDLINE, PubMed, Web of Science and SPORTSDiscus electronic databases were searched for studies that investigated the playing demands, injury trends, and physical and kinanthropometric injury risk factors of elite Australian football. Articles from similar team sports including soccer and rugby (union and league) were also included.

RESULTS

While the physical demands of elite AF have steadied over the past decade, injury rates continue to rise with more than two-thirds of all injuries affecting the lower-limbs. Body composition and musculoskeletal morphological assessments are regularly adopted in many sporting settings with current research suggesting high and low body mass are both associated with heightened injury risk. However, more extensive investigations are required to determine whether the proportions of muscle and fat are linked. Repeated assessment of musculoskeletal morphology may also provide further insight into stress fracture rates.

CONCLUSIONS

While kinanthropometric and physical attributes are highly valued within elite sporting environments, establishing a deeper connection with injury may provide practitioners with more insight into current injury trends.

The impact of vitamin D supplementation on body fat mass in elite male collegiate athletes

BACKGROUND

Whether vitamin D supplementation has any effect on body fat percentage, especially among elite athletes, remains unclear. The aim of this study was to evaluate the effect of vitamin D supplementation on serum vitamin D level in elite male collegiate athletes and to analyze its effect on body fat percentage.

METHODS

We enrolled a total of 42 elite male collegiate athletes in this prospective cohort study. In March 2020, body composition monitoring and blood test were performed. All athletes were provided with vitamin D3 supplement tablets of 25 μg/day. The use of the supplement was dependent on athletes' preference. During the study period, their club activities were stopped for 2 months due to the coronavirus disease 2019 outbreak. A second examination, similar to the first one, was performed after approximately 3 months. Supplement usage by each athlete was also confirmed. The participants were divided into a non-supplement group (without supplementation, n = 15) and a supplement group (with supplementation, n = 27).

RESULTS

Regarding baseline data at initial examination, the non-supplement and supplement groups showed significant differences in the mean body fat percentage (9.0% and 12.1%, respectively; P = 0.03) and serum 25(OH)D level (22.7 and 18.5 ng/mL, respectively, P = 0.02). At the time of the second examination, there were no significant differences in the results of both the groups. In terms of mean change value from the first to the second examination, there were significant differences in body fat percentage (1.9 and 0.2%, respectively, P = 0.02) and serum 25(OH)D level (1.7 and 7.2 ng/mL, respectively, P < 0.001) between the two groups. A significant negative correlation was observed between the change ratio of body fat percentage and change value of serum 25(OH)D level (r =  - 0.37, P = 0.02).

CONCLUSIONS

Vitamin D supplementation of 25 μg/day significantly increased the serum 25(OH)D level in elite male collegiate athletes. Vitamin D supplementation may play a role in maintaining athletes' body fat percentage under circumstances where sports activity has decreased.

Psychosocial barriers and facilitators for a successful return to work following injury within firefighters

Objective

The aim was to explore firefighter’s experiences during their recovery from injury. Focused specifically on exploring perceived psychosocial barriers and facilitators firefighters faced during recovery and return to work.

Methods

Semi-structured interviews were used to provide an in-depth understanding of the firefighter’s experiences. The semi-structured interviews were informed by a topic guide. The topic guide focused on five main themes, (1) overall experience of returning to operational duties following an injury, (2) perceived barriers experienced during their return to work, (3) perceived facilitators experienced during their return to work, (4) confidence in participating in physical activity following injury and (5) where they felt areas of improvement could be made with the return to work process. Thematic analysis of the data collected was undertaken using The Framework Method.

Results

Two main themes were sought after transcription: barriers and facilitators. From these, nine subthemes were identified (1) communication, (2) confidence in physical activity participation, (3) modified duties, (4) physiotherapy, (5) return to operational duties, (6) support, (7) inconsistency, (8) use of station gyms, (9) detachment from the watch.

Conclusions

Consideration should be made for the consistency of procedures followed during an individual’s return to work following an injury. Further research is needed to understand if the themes identified in this study are the same for other fire services. Further research is also needed to understand how the findings may be best implemented within the fire service.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00420-021-01712-z.

A cross-sectional study on foot loading patterns in elite soccer players of different ages

BACKGROUND

Alterations in plantar loading patterns are risk factors for stress injuries of the lower limb, particularly of the foot and ankle. Epidemiological studies have revealed a higher incidence of soccer-related stress fractures of the fifth metatarsal (MT V) in younger athletes than in their adult counterparts.

OBJECTIVE

The aim of the present study was to assess the plantar pressure distributions of members of four high-level soccer teams of different age groups to identify age-related differences in loading patterns.

METHODS

A total of 65 elite soccer players were included in the study. Data were computed with sensor-loaded insoles (pedar® X system, novel Inc., Munich, Germany) while the players ran in soccer shoes. Plantar pressures for nine defined regions on the preferred and nonpreferred foot were analyzed.

RESULTS

The participants consisted of 17 elite male soccer professionals from the first national league (mean 23 years, height 184 cm, weight 81 kg), 14 players from the under-21 squad (U21, 20 years, 180 cm, 75 kg), 15 players from the U17 squad (16 years, 176 cm, 69 kg) and 19 players from the U16 squad (15 years, 179 cm, 70 kg). We detected statistically significantly elevated peak pressures on the lateral aspects of the nonpreferred foot compared with the preferred foot in the U16 and U17 players, corresponding to a relative increase by 29% (p= 0.044) in the lateral midfoot, a relative increase by 24% (p= 0.031) in MT heads 4-5 in the U16 players and a difference of 18% (p= 0.049) in the lateral midfoot in the U17 players. In contrast, the U21 and adult professional players displayed symmetric plantar pressure distributions in all foot regions.

CONCLUSIONS

In contrast to adult elite soccer players, adolescents demonstrate asymmetric foot loading patterns with increased peak loads in the lateral aspects of the nonpreferred foot. Our results may provide some explanation for MT V stress fractures that occur in elite adolescents.

High union rates following surgical treatment of proximal fifth metatarsal stress fractures

PURPOSE

The primary purpose of this study was to determine the union rate and time for surgical- and non-surgical treatment of stress fractures of the proximal fifth metatarsal (MT5). The secondary purpose was to assess the rate of adverse bone healing events (delayed union, non-union, and refractures) as well as the return to sports time and rate.

METHODS

A literature search of the EMBASE (Ovid), MEDLINE (PubMed), CINAHL, Web of Science and Google Scholar databases until March 2020 was conducted. Methodological quality was assessed by two independent reviewers using the methodological index for non-randomized studies (MINORS) criteria. The primary outcomes were the union time and rate. Secondary outcomes included the delayed union rate, non-union rate, refracture rate, and return to sport time and rate. A simplified pooling technique was used to analyse the different outcomes (i.e. union rate, time to union, adverse bone healing rates, return to sport rate, and return to sport time) per treatment modality. Additionally, 95% confidence intervals were calculated for the union rate, adverse bone healing rates, and the return to sport rate.

RESULTS

The literature search resulted in 2753 articles, of which thirteen studies were included. A total of 393 fractures, with a pooled mean follow-up of 52.5 months, were assessed. Overall, the methodological quality of the included articles was low. The pooled bone union rate was 87% (95% CI 83-90%) and 56% (95% CI 41-70%) for surgically and non-surgically treated fractures, respectively. The pooled radiological union time was 13.1 weeks for surgical treatment and 20.9 weeks for non-surgical treatment. Surgical treatment resulted in a delayed union rate of 3% (95% CI 1-5%), non-union rate of 4% (95% CI 2-6%) and refracture rate of 7% (95% CI 4-10%). Non-surgical treatment resulted in a delayed union rate of 0% (95% CI 0-8%), a non-union rate of 33% (95% CI 20-47%) and a refracture rate of 12% (95% CI 5-24%), respectively. The return to sport rate (at any level) was 100% for both treatment modalities. Return to pre-injury level of sport time was 14.5 weeks (117 fractures) for surgical treatment and 9.9 weeks (6 fractures) for non-surgical treatment.

CONCLUSION

Surgical treatment of stress fractures of the proximal fifth metatarsal results in a higher bone union rate and a shorter union time than non-surgical treatment. Additionally, surgical and non-surgical treatment both showed a high return to sport rate (at any level), albeit with limited clinical evidence for non-surgical treatment due to the underreporting of data.

LEVEL OF EVIDENCE

Level IV, systematic review.

Bilateral Looser zones or pseudofractures in the anteromedial tibia as a component of medial tibial stress syndrome in athletes

PURPOSE

Medial tibial stress syndrome (MTSS) represents a common diagnosis in individuals exposed to repetitive high-stress loads affecting the lower limb, e.g., high-performance athletes. However, the diagnostic approach and therapeutic regimens are not well established.

METHODS

Nine patients, diagnosed as MTSS, were analyzed by a comprehensive skeletal analysis including laboratory bone turnover parameters, dual-energy X-Ray absorptiometry (DXA), and high-resolution peripheral quantitative computed tomography (HR-pQCT).

RESULTS

In 4/9 patients, bilateral pseudofractures were detected in the mid-shaft tibia. These patients had significantly lower levels of 25-hydroxycholecalciferol compared to patients with MTSS but similar levels of bone turnover parameters. Interestingly, the skeletal assessment revealed significantly higher bone mineral density (BMD) Z-scores at the hip (1.3 ± 0.6 vs. - 0.7 ± 0.5, p = 0.013) in patients with pseudofractures and a trend towards higher bone microarchitecture parameters measured by HR-pQCT at the distal tibia. Vitamin D supplementation restored the calcium-homeostasis in all patients. Combined with weight-bearing as tolerated, pseudofractures healed in all patients and return to competition was achieved.

CONCLUSION

In conclusion, deficient vitamin D levels may lead to pseudofractures due to localized deterioration of mineralization, representing a pivotal component of MTSS in athletes with increased repetitive mechanical loading of the lower limbs. Moreover, the manifestation of pseudofractures is not a consequence of an altered BMD nor microarchitecture but appears in patients with exercise-induced BMD increase in combination with reduced 25-OH-D levels. The screening of MTSS patients for pseudofractures is crucial for the initiation of an appropriate treatment such as vitamin D supplementation to prevent a prolonged course of healing or recurrence.

LEVEL OF EVIDENCE

III.

Recurrent and Subsequent Injuries in Professional and Elite Sport: a Systematic Review

BACKGROUND

Injury surveillance in professional sport categorises injuries as either "new" or "recurrent". In an attempt to make categorisation more specific, subsequent injury categorisation models have been developed, but it is not known how often these models are used. The aim was to assess how recurrent and subsequent injuries are reported within professional and elite sport.

METHODS

Online databases were searched using a search strategy. Studies needed to prospectively report injury rates within professional or elite sports that have published consensus statements for injury surveillance.

RESULTS

A total of 1322 titles and abstract were identified and screened. One hundred and ninety-nine studies were screened at full text resulting in 81 eligible studies. Thirty studies did not report recurrent injuries and were excluded from data extraction. Within the studies that reported recurrent injuries, 21 reported the number and percentage; 13 reported only the proportion within all injuries; three reported only the number; five reported the number, percentage and incidence; and two only reported the incidence. Seven studies used subsequent injury terminology, with three reporting subsequent injury following concussion, one using an amended subsequent injury model and three using specific subsequent injury categorisation models. The majority of subsequent injuries (ranging from 51 to 80%) were categorised as different and unrelated to the index injury. The proportion of recurrent injuries (exact same body area and nature related to index injury) ranged from 5 to 21%.

CONCLUSIONS

Reporting recurrent or subsequent injuries remains inconsistent, and few studies have utilised subsequent injury models. There is limited understanding of subsequent injury risk, which may affect the development of injury prevention strategies.

TRIAL REGISTRATION

CRD42019119264.

A Narrative Review of Metatarsal Bone Stress Injury in Athletic Populations: Etiology, Biomechanics, and Management

Metatarsal bone stress injuries (BSIs) are common in athletic populations. BSIs are overuse injuries that result from an accumulation of microdamage that exceeds bone remodeling. Risk for metatarsal BSI is multifactorial and includes factors related to anatomy, biology, and biomechanics. In this article, anatomic factors including foot type, metatarsal length, bone density, bone geometry, and intrinsic muscle strength, which each influence how the foot responds to load, are discussed. Biologic factors such as low energy availability and impaired bone metabolism influence the quality of the bone. Finally, the influence of biomechanical loads to bone such as peak forces, load rates, and loading cycles are reviewed. General management of metatarsal BSI is discussed, including acute care, rehabilitation, treatment of refractory metatarsal BSI, and evaluation of healing/return to sport. Finally, we identify future research priorities and emerging treatments for metatarsal BSI.

Anatomic Characteristics of Tissues Attached to the Fifth Metatarsal Bone

Background

Two types of stress, bending stress and traction stress, have been reported to be involved in the mechanism of Jones fracture. However, little is known about the risk factors for traction stress.

Purpose

To classify the attachment position of the peroneus brevis muscle (PB), peroneus tertius (PT), lateral band of the plantar aponeurosis (LB), and the long plantar ligament (LPL), focusing on the zone where a Jones fracture occurs (zone 2), and to compare the footprint area of each tissue type.

Study Design

Descriptive laboratory study.

Methods

This study examined 102 legs from 55 Japanese cadavers. Type classification was performed by focusing on the positional relationship between each tissue attachment and the zone where Jones fracture occurs (zone 2). The classifications were as follows: type I, attached proximal to the border between zones 1 and 2; type IIa, attached to the border between zones 1 and 2 with one attached part; and type IIb, attached across the border between zones 1 and 2 with two or more attached parts. The footprint areas of the PB, PT, LB, and LPL were compared between tissue types and within each attachment classification.

Results

The PB was recorded as type I in 41 feet (40.2%), type IIa in 56 feet (54.9%), and type IIb in 5 feet (4.9%); the PT was recorded as type IIa in 54 feet (60.0%) and type IIb in 36 feet (40.0%); and the LB was recorded as type I in 27 feet (26.5%) and type IIa in 75 feet (73.5%). The LPL did not attach to the fifth metatarsal bone. No significant difference was found in the footprint area between type I PB and type I LB.

Conclusion

The results indicate that type I, which attaches proximal to zone 2, occurs with PB and LB, and there was no significant difference in the footprint area between them. These findings suggest that type I is involved in traction stress. In the future, biomechanical research based on the results of this study will be necessary.

Clinical Relevance

The results of this study provide basic research for investigating the mechanism of Jones fracture and the cause of delayed healing.

Stress fractures in uncommon location: Six case reports and review of the literature

BACKGROUND

Individuals' interest in sports activities has been increasing, contributing to more stress fracture occurrences in uncommon locations on the skeleton. In this study, several cases of stress fractures in atypical locations are presented, and the possibility of combining diagnostic methods to make accurate and quick diagnoses is explored. Additionally, different causes of stress fractures, as well as various modalities of treatment, are highlighted. Other potential factors of stress fractures were identified by a literature review.

CASE SUMMARY

Six cases of stress fractures in the calcaneus, intermediate cuneiform bone, sacrum, tibia (bilateral), navicular bone and femoral neck are presented, with different types of diagnostic imaging and treatments. All of the cases were associated with an aspect of mobility because all of the patients were physically active in various sport disciplines.

CONCLUSION

The type of therapeutic procedure selected should depend on the specific clinical case, i.e., the patient's condition and level of physical activity.

Pathoanatomy of the Jones Fracture in Male University Soccer Players

BACKGROUND

Jones fractures are relatively common in soccer players and require an extended recovery period because this type of fracture has a high incidence of delayed union, nonunion, and refracture. There has been some previous research on risk factors for Jones fracture, but no study has yet investigated the effect of the length of the fifth metatarsal bone and the positional relationship of the articular surface of the fifth metatarsal bones and the tarsal bones. Clarification of the characteristics of the foot structure that predispose soccer players to Jones fracture may aid in the prevention of this injury.

PURPOSE

To investigate the association between Jones fracture and foot structure as assessed with a mapping system on weightbearing dorsoplantar and lateral foot radiographs.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We used a mapping system to evaluate the radiographs of 60 feet from 30 university soccer players with Jones fractures and a control group of 60 feet from 60 male university soccer players without Jones fracture. The groups were compared regarding the length of the fifth metatarsal and the positions of the metatarsal and tarsal bones.

RESULTS

Analysis of weightbearing dorsoplantar foot radiographs showed that the fifth metatarsal was significantly longer and that its proximal tip was positioned more proximally in the Jones fracture group as compared with the control group. Analysis of weightbearing lateral foot radiographs showed that the reference points for the medial arch were significantly higher in the Jones fracture group than in the control group.

CONCLUSION

This study indicated that the proximally longer fifth metatarsal may cause greater stress at the base of the fifth metatarsal bone because the lever arm becomes long. In addition, high medial longitudinal arch may contribute to increased load on the lateral side of the foot. Thus, these anatomic features may be useful to identify soccer players at high risk of Jones fracture at medical checkup.

Early return to playing professional football following fixation of 5th metatarsal stress fractures may lead to delayed union but does not increase the risk of long-term non-union

PURPOSE

5th metatarsal stress fractures are frequently encountered in professional football. There is concern that early return to play following intra-medullary screw fixation may lead to an increased risk of delayed union. The purpose of the study was to assess whether an early return to play after surgical fixation of 5th metatarsal fractures in professional football players is a risk factor for delayed union and the effect of this on the ultimate clinical outcome.

METHODS

Retrospective review of prospectively collected data of a series of 37 professional football players following intramedullary screw fixation of 5th metatarsal stress fractures. End points included time of return to play and to radiological union of the fracture.

RESULTS

At a minimum follow-up of 24 months the mean return to play was 10.5 weeks and mean time to complete radiological union was 12.7 weeks. Return to play at 8 weeks or less resulted in a higher risk of delayed radiological union (24% at 3 months), but this neither prevented the athlete from continuing to play football nor did it affect the ultimate risk of non-union (3% overall). A re-fracture occurred in 1 patient (3%) at 10 months who previously had complete radiographic union at 9 weeks.

CONCLUSION

Intramedullary screw fixation of 5th metatarsal stress fractures leads to a predictable time of return to play and a low rate of non-union. If players return to play at 8 weeks or less a persistent line may be expected in up to a quarter of patients. However, if asymptomatic this radiological finding does not mean that athletes must avoid playing football as ultimately a good outcome is expected with low rates of non-union and refracture.

LEVEL OF EVIDENCE

Case series, Level IV.

Characteristics of plantar pressure distribution in elite male soccer players with or without history of proximal fifth metatarsal fracture: a case-control study

[Purpose] Studies have demonstrated a relationship between plantar pressure distribution and proximal fifth metatarsal fracture. We aimed to investigate the plantar pressure patterns of soccer players with or without a history of proximal fifth metatarsal fracture. [Participants and Methods] Fifty-one male soccer players (31 professional, 20 high-school) participated in this study (mean age, weight, and height ± SD: 21.1 ± 4.7 years, 68.8 ± 5.8 kg, and 175.4 ± 5.9 cm, respectively). Seven of them had a history of proximal fifth metatarsal fracture before this study (the fracture group) and 44 had no history of fracture (the control group). A Win-Pod (Medicapteurs) platform was used to measure foot pressure forces. The center of plantar pressure was measured during double and single-limb stances for 25 seconds. Fifth metatarsal pressure and the center of plantar pressure angle was calculated from the walking footprint. The calculated data were compared between the fracture group and the control group. [Results] Comparisons between the fracture and control groups in terms of morphology and the center of plantar pressure length showed no significant differences. However, the fifth metatarsal pressure and the center of plantar pressure angle were significantly higher in the fracture group. [Conclusion] The results of this study revealed that players with excessive loading in the lateral areas of the foot while walking have a risk of developing proximal fifth metatarsal fracture.

Radiographic Analysis of National Football League Players' Fifth Metatarsal Morphology Relationship to Proximal Fifth Metatarsal Fracture Risk

BACKGROUND:

Fractures of the proximal fifth metatarsal are one of the most common foot injuries in athletes. Repetitive stresses endured by the fifth metatarsal can lead to stress fracture, delayed union, and refracture, making optimal treatment challenging. A radiographic analysis of fifth metatarsal morphology and foot type in National Football League (NFL) players was performed to investigate morphologic risk factors for these injuries.

METHODS:

This was a case-control study that looked at NFL players treated between 1992 and 2012, as well as participants at the NFL Combine. Ninety-six feet (51 athletes) were included. Fractures were present in 15 feet. Two reviewers assessed fifth metatarsal morphology and foot type on anteroposterior, lateral, and oblique radiographs. Differences in foot type and metatarsal morphology between athletes with and without fractures were determined.

RESULTS:

On anteroposterior radiographs, significant differences in apex medullary canal width, 4-5 intermetatarsal angle, fifth metatarsal angle, and talar head uncovering were observed between fractured and non-fractured feet ( P = .001, .003, .004, .008, respectively). On lateral radiographs, significant differences in the fifth metatarsal length, distance to apex, apex height, fifth metatarsal angle, and talocalcaneal angle were observed between fractured and nonfractured feet ( P = .04, .01, .02, .01, .01, respectively). On oblique radiographs, a significant difference was observed in apex height between fractured and nonfractured feet ( P = .002).

CONCLUSION:

Individuals with long, narrow, and straight fifth metatarsals with an adducted forefoot were most at risk for fifth metatarsal fractures. With this insight, attempts at fracture prevention can be implemented via footwear modifications, orthoses, and off-loading braces that account for those aforementioned morphologic attributes that place athletes at risk.

LEVEL OF EVIDENCE:

Level III, retrospective comparative study.

Playing football on artificial turf as a risk factor for fifth metatarsal stress fracture: a retrospective cohort study

OBJECTIVE

The fifth metatarsal stress fracture is a common injury among football players. Although several risk factors have been proposed, the association between the playing surface and development of fifth metatarsal stress fractures (MT-5) has not been evaluated. We conducted an epidemiological study using a computer-based survey to investigate the association between the playing surface and development of MT-5.

METHODS

This study included 1854 football players, of which 41 experienced MT-5 within the past 24 months. Baseline demographic data and the percentage of time spent playing on artificial turf and clay fields were compared between the non-MT-5 and MT-5 player groups, and the risks for development of MT-5 associated with the playing surfaces were estimated by univariate and multivariate analyses.

RESULTS

There were significant differences in body mass index, years of play, playing categories and playing time on artificial turf between non-MT-5 and MT-5 groups (p<0.05). Generalised estimating equations analyses adjusted for multiple confounders demonstrated that relative to the risk of playing <20% of the time on each surface, the OR (OR: 95% CI) for MT-5 for playing on artificial turf >80% of the time increased (3.44: 1.65 to 7.18), and for playing on a clay field 61%-80% of the time, the OR decreased (0.25: 0.11 to 0.59).

CONCLUSIONS

A higher percentage of playing time on an artificial turf was a risk factor for developing MT-5 in football players. This finding could be beneficial for creating strategies to prevent MT-5.

Intensive terrestrial or marine locomotor strategies are associated with inter- and intra-limb bone functional adaptation in living female athletes

OBJECTIVES

To systematically characterize intra-limb patterns of skeletal plasticity to loading among living women, in order to better understand regional complexity in structural adaptation within the lower limb and more accurately infer behavior in the past.

MATERIALS AND METHODS

We used peripheral quantitative computed tomography imaging of the femur, tibia, first and second metatarsals to quantify bone morphology among female controls and athletes representative of either terrestrial or marine mobility, grouped by loading category (odd-impact, repetitive low-impact, and high-magnitude). Parameters included midshaft bone density, areas, rigidity, and shape, epiphyseal bone densities and areas. We assessed between-group differences and the influence of training history on significant variation among the loading groups.

RESULTS

Terrestrial mobility strategies were best distinguished by significant midshaft periosteal hypertrophy across the lower limb/foot relative to controls, and by particularly high midshaft femoral and tibial cortical bone areas relative to rowers. Enhanced midshaft bone area was typically paired with decreased bone density among athlete groups. Sport-specific variation in training duration/timing was significantly correlated with multiple midshaft parameters.

DISCUSSION

Results demonstrate characteristic patterns of intra-limb adaptation to terrestrial and marine mobility strategies among active women relative to controls, and highlight components of these patterns that may be shaped in part by differences in loading duration/timing. Additionally, our findings support constraints on skeletal variation in the distal tibia and foot relative to more proximal locations about the knee among living women. For example, metatarsal variation was constrained, but where present reflected sport-specific variation in force distribution in the foot.

Functional Basis of Asymmetrical Lower-Body Skeletal Morphology in Professional Australian Rules Footballers

Hart, NH, Newton, RU, Weber, J, Spiteri, T, Rantalainen, T, Dobbin, M, Chivers, P, and Nimphius, S. Functional basis of asymmetrical lower-body skeletal morphology in elite Australian footballers. J Strength Cond Res 34(3): 791-799, 2020-Bone strength is a product of its material and structural properties and is highly responsive to mechanical load. Given the measureable and adaptable features of bone, and thus relevance to medical screening, injury prevention, and injury management in athletes, this study describes the lower-body skeletal morphology of professional Australian rules footballers. Using a cross-sectional and quantitative study design, 54 professional Australian rules football players (n = 54; age: 22.4 ± 3.8 years; height: 189.0 ± 7.5 cm; body mass: 86.0 ± 8.6 kg; tibial length: 436.1 ± 29.2 mm; and body fat: 9.9 ± 1.7%) underwent tibiofibular peripheral quantitative computed tomography scans for the kicking and support limbs, and a whole-body dual-energy X-ray absorptiometry scans. The support leg was significantly stronger than the kicking leg (bone strength: p ≤ 0.001; d = 0.47) with significantly greater bone mass (p < 0.001; d = 0.28), cross-sectional areas (p ≤ 0.002; d = 0.20), and greater cortex thickness (p = 0.017; d = 0.20), owing to significantly greater periosteal apposition (p ≤ 0.001; d = 0.29) and endocortical expansion (p = 0.019; d = 0.13), despite significantly lower cortical density (p = 0.002; d = -0.25). Disparate skeletal morphology between limbs highlights context-specific adaptive responses to mechanical loads experienced during game-based tasks. Practitioners should concomitantly measure material and structural properties of musculoskeletal tissue when examining fragility or resilience to better inform medical screening, monitoring, and injury risk stratification. Support leg axial loading highlights a potential avenue for interventions aiming to remediate or optimize bone cross-sectional area.

Articular and peri-articular hip lesions in soccer players. The importance of imaging in deciding which lesions will need surgery and which can be treated conservatively?

Soccer is one of the most popular sports worldwide engaging millions of participants each year. During play, injuries occur rather frequently and most of them involve the hip joint and the surrounding structure. In professional athletes, injuries are often complex scenarios and in the case of misdiagnosis, patients' return to play is delayed or it may progress to a more serious injury with consequent damage for their career and for the soccer team. The most frequent articular pathologies are Femoro-acetabular impingement and labral tears. Stress fracture, avulsion, ischiofemoral impingement, subspine impingement, athletic pubalgia, muscle injuries and Morel-Levallèe lesion are the most frequent hip peri-articular pathologies whereas snapping hip may be both intra- or extra-articular pathology. With an increasing number of football players, the radiologist plays a crucial role in the detection and characterization of the extent of the injuries. This article reviews the current imaging concepts frequently seen in injuries around the hips of professional football players focusing in particular on the most suitable therapeutic approaches, whether surgical or conservative.

Tension band plating of an anterior tibial stress fracture nonunion in an elite athlete, initially treated with intramedullary nailing: a case report

Background

Leg pain in athletes is a common condition and is often related to tibial stress fracture. When non-operative treatment fails, the optimal surgical treatment is controversial. The aim of this study was to report a case of tension band plating of an anterior tibial stress fracture nonunion, treated previously with intramedullary nailing. To the best of our knowledge, this is the first reported case in which tension band plating was placed without removing the preexisting intramedullary nail.

Case presentation

The tibial shaft is a common location of stress fracture in athletes. Anterior tibial stress fractures are difficult to manage. When conservative treatment fails, intramedullary nailing is the mainstay of treatment. However, nonunion is a serious complication. In our case, a non-united anterior tibial stress fracture, treated with intramedullary nailing, was addressed with the application of a compression prebended plate over the nail in a 23-year-old French man of African origin who is an elite football player. At 3-months postoperatively he was pain free and started light exercises. At 6-months postoperatively, complete radiologic union of the fracture was evident. He was symptom free; he resumed at that time a full training program and he returned to play football at preinjury high competition level.

Conclusions

Compression plating is a valuable method of treating non-united anterior tibial stress fractures. We believe that anterior tension band plating is superior to intramedullary nailing in managing anterior tibial stress fractures, not only after failure of intramedullary nailing, but also as a first-line surgical treatment. This technique offers advantages, such as no violation of the extensor mechanism and risk of anterior knee pain, and directly addresses the underlying problem of distraction forces acting on the anterior tibial cortex and compromising fracture healing. Especially in high-level athletes, who cannot tolerate prolonged inactivity, early surgical intervention of anterior tibial stress fractures with tension band plating is a reliable option that can accelerate recovery.

Fifth metatarsal stress fracture in elite male football players: an on-field analysis of plantar loading

Objective

Evaluate plantar loading during ‘on-field’ common football movements in players after fifth metatarsal (MT-5) stress fracture and compare with matched healthy players.

Methods

Fourteen elite male soccer players participated in the study conducted on a natural grass playing surface using firm ground football boots. Seven players who had suffered a primary stress fracture (MT-5 group) and seven matched healthy players (controls, CON) performed three common football movements while in-shoe plantar loading data were collected.

Results

Large between-group differences exist for maximal vertical force normalised to bodyweight (F_max) at the lateral toes (2-5) of the stance leg during a set-piece kick (MT-5: 0.2±0.06 bodyweight (BW), CON: 0.1±0.05 BW, effect size (ES) 1.4) and the curved run where the MT-5 group showed higher F_max with very large effect size at the lateral forefoot of the injured (closest to curve) limb when running a curve to receive a pass (MT-5 injured−CON=0.01 BW, ES 1.5). Small between-group differences were evident during straight-line running. However, between-limb analysis of MT-5 group showed significant unloading of the lateral forefoot region of the involved foot.

Conclusions

Elite male football players who have returned to play after MT-5 stress fracture display significantly higher maximum plantar force at the lateral forefoot and lateral toes (2-5) compared with healthy matched control players during two football movements (kick and curved run) with the magnitude of these differences being very large. These findings may have important implications for manipulating regional load during rehabilitation or should a player report lateral forefoot prodromal symptoms.

Anterior cruciate ligament ruptures in German elite soccer players: Epidemiology, mechanisms, and return to play

BACKGROUND

Anterior cruciate ligament ruptures (ACLRs) are severe sports-related injuries with significant consequences for affected players and teams. This study aims to identify the epidemiology and injury-related lay-off after ACLR in professional male soccer players from the first-division German Bundesliga.

METHODS

Exposure times and incidence of anterior cruciate ligament ruptures were collected during 7.5 consecutive seasons using two media-based registers.

RESULTS

A total of 72 total ACLRs were registered in 66 different players with an incidence of 0.040 per 1000h of exposure (95% CI 0.009-0.12). On average there were 9.6 ACLRs per season and 0.53 per team and season. The mean age of players affected was 24 (standard deviation±3.6) years. The number of ACLRs recorded per season fluctuated during the period observed. Goalkeepers are significantly (P<0.05) less prone to suffer an ACLR compared to outfield players.

CONCLUSIONS

Understanding ACLR loading mechanisms, knowing risk factors for the injury and mean off time after ACLR are essential information for the coach, the medical staff, the elite soccer players, the insurance and team managers. Our results are in accordance with reports based on information from medical team staff. Therefore, our analysis of ACLR based on media sources may serve as an alternative for injury reports in elite soccer. The information of this study may be helpful for the medical staff taking care of professional soccer players and for orthopedic surgeons performing ACL reconstructions in this patient population.

Fractures in German elite male soccer players

BACKGROUND

Aim of this retrospective cohort study was to identify fracture epidemiology and off times after different types of fractures in German male elite soccer players from the first division Bundesliga based on information from the public media.

METHODS

Exposure and fracture data over 7.5 consecutive seasons (2009/10 until the first half of 2016/17) were collected from two media-based register (transfermarkt.de® and kicker.de®).

RESULTS

Overall, 357 fractures from 290 different players were recorded with an incidence of 0.19/1000 hours of exposure (95% CI: 0.14-0.24). Most fractures in German elite soccer players involved the lower extremities (35.3%), the head/face (30.3%) and the upper extremities (24.9%). The median off time after a fracture in German elite male professional soccer in 7.5 Season was 51.1 days (range 0-144). The number of fractures per 100 players per season decreased between 2009 and 2016. There was no significant difference in overall fracture incidence when comparing players at different position (P=0.11). Goalkeepers have a significantly (P<0.02) higher likelihood of suffering hand and finger fractures and they are significantly (P<0.03) less prone of suffering foot fractures, cranial and maxillofacial fractures (P<0.04). compared to outfield players.

CONCLUSIONS

This study can confirm that male professional soccer teams experience 1-2 fractures per season in German elite soccer. The incidence of fractures in elite German soccer players decreased between 2009 and 2016. The most fractures occur in the lower extremities and there is no difference in overall fracture risk for players at different playing positions. The information from our study might be of a great importance to medical practitioners, soccer coaches and soccer manager.

Characteristics of the Foot Static Alignment and the Plantar Pressure Associated with Fifth Metatarsal Stress Fracture History in Male Soccer Players: a Case-Control Study

BACKGROUND

There is a large amount of information regarding risk factors for fifth metatarsal stress fractures; however, there are few studies involving large numbers of subjects. This study aimed to compare the static foot alignment and distribution of foot pressure of athletes with and without a history of fifth metatarsal stress fractures.

METHODS

The study participants comprised 335 collegiate male soccer players. Twenty-nine with a history of fifth metatarsal stress fractures were in the fracture group and 306 were in the control group (with subgroups as follows: 30 in the fracture foot group and 28 in the non-fracture group). We measured the foot length, arch height, weight-bearing leg-heel alignment, non-weight-bearing leg-heel alignment, forefoot angle relative to the rearfoot, forefoot angle relative to the horizontal axis, and foot pressure.

RESULTS

The non-weight-bearing leg-heel alignment was significantly smaller and the forefoot angle relative to the rearfoot was significantly greater in the fracture foot group than in the control foot group (P = 0.049 and P = 0.038, respectively). With regard to plantar pressure, there were no significant differences among the groups. Midfield players had significantly higher rates of fifth metatarsal stress fracture in their histories, whereas defenders had significantly lower rates (chi-square = 13.2, P < 0.05). There were no significant differences in the frequency of fifth metatarsal stress fractures according to the type of foot (kicking foot vs. pivoting foot) or the severity of ankle sprain.

CONCLUSIONS

Playing the midfield position and having an everted rearfoot and inverted forefoot alignment were associated with fifth metatarsal stress fractures. This information may be helpful for preventing fifth metatarsal stress fracture recurrence. More detailed load evaluations and a prospective study are needed in the future.

Management of sports injuries of the foot and ankle: An update

Injuries to the foot in athletes are often subtle and can lead to a substantial loss of function if not diagnosed and treated appropriately. For these injuries in general, even after a diagnosis is made, treatment options are controversial and become even more so in high level athletes where limiting the time away from training and competition is a significant consideration. In this review, we cover some of the common and important sporting injuries affecting the foot including updates on their management and outcomes. Cite this article: Bone Joint J 2016;98-B:1299-1311.

Fracture epidemiology in male elite football players from 2001 to 2013: 'How long will this fracture keep me out?'

BACKGROUND

Determining fracture risk and rehabilitation periods after specific fractures in professional football is essential for team planning.

AIM

To identify fracture epidemiology and absences after different types of fractures in male professional football players.

METHODS

2439 players from 41 professional male teams in 10 countries were followed prospectively from 2001 to 2013. Team medical staff registered fractures, absences after fractures and player exposure.

RESULTS

364 fractures were recorded, with an incidence of 0.27/1000 h of exposure (95% CI 0.25 to 0.30). The incidence of traumatic fractures was 0.25 (0.22 to 0.27) and that of stress fractures was 0.03 (0.02 to 0.04). 45% of traumatic fractures and 86% of stress fractures affected the lower extremities. Absence after a fracture was 32 days (1-278) (median (range)), compared to that after a traumatic fracture of 30 days (1-278) and a stress fracture of 65 days (6-168) (p<0.001). Annual fracture incidence was stable during the study period (R(2)=0.051, b=-0.011 (95% CI -0.043 to 0.021)). Young players had a relative risk of 10.9 (3.3 to 35.6) of sustaining stress fractures compared to old players (p<0.01). The fracture incidence did not differ between individuals in different playing positions (p=0.10).

SUMMARY

A male professional football team can expect 1 to 2 fractures per season. There are more traumatic fractures than stress fractures; while most fractures affect the lower extremities, stress fractures yield longer absences than traumatic fractures and young players have more stress fractures than old players. There is no difference in risk among players at different playing positions.

Evaluating the Risk of a Fifth Metatarsal Stress Fracture by Measuring the Serum 25-Hydroxyvitamin D Levels

BACKGROUND

The fifth metatarsal bone is a common site of stress fractures in soccer athletes. Although several endocrine risk factors for stress fractures have been proposed, the endocrine risks for fifth metatarsal (5-MT) stress fractures have not been evaluated.

METHODS

To evaluate the endocrine risks of fifth metatarsal stress fractures, we conducted a cumulative case-control study. The present study included 37 athletes, of which 18 had a history of a zone 2 or zone 3 fifth metatarsal stress fracture and 19 controls. We analyzed serum 25-hydroxyvitamin D (25-OHD), serum parathyroid hormone (PTH), as well as biochemical markers of bone turnover by univariate or multivariate analyses.

RESULTS

Logistic regression analyses adjusted for multiple confounders revealed that insufficient serum 25-OHD levels less than 30 ng/mL (odds ratio [OR], 23.3), higher serum PTH levels (OR, 1.01), or higher serum bone-specific isoform of alkaline phosphatase levels (OR, 1.10) rather than serum tartrate-resistant acid phosphatase 5b were associated with statistically significantly increased odds of 5-MT stress fractures. A postestimation calculation demonstrated that 25-OHD levels of 10 and 20 ng/mL were associated with 5.1 and 2.9 times greater odds for 5-MT stress fractures, respectively.

CONCLUSION

25-OHD insufficiency was associated with an increased incidence of 5-MT stress fractures. This insight may be useful for intervening to prevent 5-MT stress fractures.

LEVEL OF EVIDENCE

Level III, case-control study.

Pathogenesis of Fifth Metatarsal Fractures in College Soccer Players

Background:

The pathogenesis of fifth metatarsal stress fractures remains uncertain.

Hypothesis:

Physical characteristics and environmental factors, which have received limited attention in the literature thus far, might be involved in the development of fifth metatarsal stress fractures.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

To test the study hypothesis, a medical examination and survey of the living environment of collegiate soccer players was conducted and correlated with the existence of fifth metatarsal stress fractures. The survey and measurements were conducted in 273 male athletes from the same college soccer team between 2005 and 2013. A medical examination comprising assessment of stature, body weight, body mass index, foot–arch height ratio, toe-grip strength, quadriceps angle, leg-heel angle, functional reach test, single-leg standing time with eyes closed, straight-leg raise angle, finger-floor distance, heel-buttock distance, ankle joint range of motion, and a general joint laxity test were performed once a year, along with a questionnaire survey. The survey was also repeated when a fifth metatarsal stress fracture was diagnosed. The study participants were separated into a fifth metatarsal stress fracture injury group and a noninjury group. The measurement items and survey items were compared, and the association between the factors and the presence or absence of injuries was analyzed.

Results:

Toe-grip strength was significantly weaker in the injury group compared with the noninjury group, suggesting that weak toe-grip is associated with fifth metatarsal stress fracture (P < .05). In addition, fifth metatarsal stress fractures were more common in the nondominant leg (P < .05). Between-group comparisons of the other items showed no statistically significant differences.

Conclusion:

The association between weak toe-grip strength and fifth metatarsal fracture suggests that weak toe-grip may lead to an increase in the load applied onto the lateral side of the foot, resulting in stress fracture. The finding of stress fracture being more common in the nondominant leg needs further study.

Return to sports after stress fractures of the tibial diaphysis: a systematic review

INTRODUCTION

This review aims to provide information on the time taken to resume sport following tibial diaphyseal stress fractures (TDSFs).

SOURCES OF DATA

A systematic search of Medline, EMBASE, CINHAL, Cochrane, Web of Science, PEDro, Sports Discus, Scopus and Google Scholar was performed using the keywords 'tibial', 'tibia', 'stress', 'fractures', 'athletes', 'sports', 'non-operative', 'conservative', 'operative' and 'return to sport'.

AREAS OF AGREEMENT

Twenty-seven studies were included: 16 reported specifically on anterior TDSFs and 5 on posterior TDSFs. The general principles were to primarily attempt non-operative management for all TDSFs and to consider operative intervention for anterior TDSFs that remained symptomatic after 3-6 months. Anterior TDSFs showed a prolonged return to sport.

AREAS OF CONTROVERSY

The best time to return to sport and the optimal management modalities for TDSFs remain undefined.

GROWING POINTS

Management of TDSFs should include a full assessment of training methods, equipment and diet to modify pre-disposing factors.

AREAS TIMELY FOR DEVELOPING RESEARCH

Future prospective studies should aim to establish the optimal treatment modalities for TDSFs.

RANK/RANKL/OPG pathway: genetic associations with stress fracture period prevalence in elite athletes

CONTEXT

The RANK/RANKL/OPG signalling pathway is important in the regulation of bone turnover, with single nucleotide polymorphisms (SNPs) in genes within this pathway associated with bone phenotypic adaptations.

OBJECTIVE

To determine whether four SNPs associated with genes in the RANK/RANKL/OPG signalling pathway were associated with stress fracture injury in elite athletes.

DESIGN, PARTICIPANTS, AND METHODS

Radiologically confirmed stress fracture history was reported in 518 elite athletes, forming the Stress Fracture Elite Athlete (SFEA) cohort. Data were analysed for the whole group and were sub-stratified into male and cases of multiple stress fracture groups. Genotypes were determined using proprietary fluorescence-based competitive allele-specific PCR assays.

RESULTS

SNPs rs3018362 (RANK) and rs1021188 (RANKL) were associated with stress fracture injury (P<0.05). 8.1% of the stress fracture group and 2.8% of the non-stress fracture group were homozygote for the rare allele of rs1021188. Allele frequency, heterozygotes and homozygotes for the rare allele of rs3018362 were associated with stress fracture period prevalence (P<0.05). Analysis of the male only group showed 8.2% of rs1021188 rare allele homozygotes had suffered a stress fracture whilst 2.5% of the non-stress fracture group were homozygous. In cases of multiple stress fractures, homozygotes for the rare allele of rs1021188 and individuals possessing at least one copy of the rare allele of rs4355801 (OPG) were shown to be associated with stress fracture injury (P<0.05).

CONCLUSIONS

The data support an association between SNPs in the RANK/RANKL/OPG signalling pathway and the development of stress fracture injury. The association of rs3018362 (RANK) and rs1021188 (RANKL) with stress fracture injury susceptibility supports their role in the maintenance of bone health and offers potential targets for therapeutic interventions.

Reproducibility of a peripheral quantitative computed tomography scan protocol to measure the material properties of the second metatarsal

Background

Peripheral quantitative computed tomography (pQCT) is an established technology that allows for the measurement of the material properties of bone. Alterations to bone architecture are associated with an increased risk of fracture. Further pQCT research is necessary to identify regions of interest that are prone to fracture risk in people with chronic diseases. The second metatarsal is a common site for the development of insufficiency fractures, and as such the aim of this study was to assess the reproducibility of a novel scanning protocol of the second metatarsal using pQCT.

Methods

Eleven embalmed cadaveric leg specimens were scanned six times; three times with and without repositioning. Each foot was positioned on a custom-designed acrylic foot plate to permit unimpeded scans of the region of interest. Sixty-six scans were obtained at 15% (distal) and 50% (mid shaft) of the second metatarsal. Voxel size and scan speed were reduced to 0.40 mm and 25 mm.sec^-1. The reference line was positioned at the most distal portion of the 2^nd metatarsal. Repeated measurements of six key variables related to bone properties were subject to reproducibility testing. Data were log transformed and reproducibility of scans were assessed using intraclass correlation coefficients (ICC) and coefficients of variation (CV%).

Results

Reproducibility of the measurements without repositioning were estimated as: trabecular area (ICC 0.95; CV% 2.4), trabecular density (ICC 0.98; CV% 3.0), Strength Strain Index (SSI) - distal (ICC 0.99; CV% 5.6), cortical area (ICC 1.0; CV% 1.5), cortical density (ICC 0.99; CV% 0.1), SSI – mid shaft (ICC 1.0; CV% 2.4). Reproducibility of the measurements after repositioning were estimated as: trabecular area (ICC 0.96; CV% 2.4), trabecular density (ICC 0.98; CV% 2.8), SSI - distal (ICC 1.0; CV% 3.5), cortical area (ICC 0.99; CV%2.4), cortical density (ICC 0.98; CV% 0.8), SSI – mid shaft (ICC 0.99; CV% 3.2).

Conclusions

The scanning protocol generated excellent reproducibility for key bone properties measured at the distal and mid-shaft regions of the 2^nd metatarsal. This protocol extends the capabilities of pQCT to evaluate bone quality in people who may be at an increased risk of metatarsal insufficiency fractures.

Changes in plantar loading based on shoe type and sex during a jump-landing task

CONTEXT

Metatarsal stress fractures are common in cleated-sport athletes. Previous authors have shown that plantar loading varies with footwear, sex, and the athletic task.

OBJECTIVE

To examine the effects of shoe type and sex on plantar loading in the medial midfoot (MMF), lateral midfoot (LMF), medial forefoot (MFF), middle forefoot (MidFF), and lateral forefoot (LFF) during a jump-landing task.

DESIGN

Crossover study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty-seven recreational athletes (14 men, 13 women) with no history of lower extremity injury in the last 6 months and no history of foot or ankle surgery.

MAIN OUTCOME MEASURE(S)

The athletes completed 7 jumping trials while wearing bladed-cleat, turf-cleat, and running shoes. Maximum force, contact area, contact time, and the force-time integral were analyzed in each foot region. We calculated 2 × 3 analyses of variance (α = .05) to identify shoe-condition and sex differences.

RESULTS

We found no shoe × sex interactions, but the MMF, LMF, MFF, and LFF force-time integrals were greater in men (P < .03). The MMF maximum force was less with the bladed-cleat shoes (P = .02). Total foot and MidFF maximum force was less with the running shoes (P < .01). The MFF and LFF maximum forces were different among all shoe conditions (P < .01). Total foot contact area was less in the bladed-cleat shoes (P = .01). The MMF contact area was greatest in the running shoes (P < .01). The LFF contact area was less in the running shoes (P = .03). The MFF and LFF force-time integrals were greater with the bladed-cleat shoes (P < .01). The MidFF force-time integral was less in the running shoes (P < .01).

CONCLUSIONS

Independent of shoe, men and women loaded the foot differently during a jump landing. The bladed cleat increased forefoot loading, which may increase the risk for forefoot injury. The type of shoe should be considered when choosing footwear for athletes returning to activity after metatarsal stress fractures.

Recurrence of Achilles tendon injuries in elite male football players is more common after early return to play: an 11-year follow-up of the UEFA Champions League injury study

BACKGROUND

There is limited information about Achilles tendon disorders in professional football.

AIMS

To investigate the incidence, injury circumstances, lay-off times and reinjury rates of Achilles tendon disorders in male professional football.

METHODS

A total of 27 clubs from 10 countries and 1743 players have been followed prospectively during 11 seasons between 2001 and 2012. The team medical staff recorded individual player exposure and time-loss injuries.

RESULTS

A total of 203 (2.5% of all injuries) Achilles tendon disorders were registered. A majority (96%) of the disorders were tendinopathies, and nine were partial or total ruptures. A higher injury rate was found during the preseason compared with the competitive season, 0.25 vs 0.18/1000 h (rate ratio (RR) 1.4, 95% CI 1.1 to 2.0; p=0.027). The mean lay-off time for Achilles tendinopathies was 23±37 (median=10, Q1=4 and Q3=24) days, while a rupture of the Achilles tendon, on average, caused 161±65 (median=169, Q1=110 and Q3=189) days of absence. Players with Achilles tendon disorders were significantly older than the rest of the cohort, with a mean age of 27.2±4 years vs 25.6±4.6 years (p<0.001). 27% of all Achilles tendinopathies were reinjuries. A higher reinjury risk was found after short recovery periods (31%) compared with longer recovery periods (13%) (RR 2.4, 95% CI 2.1 to 2.8; p<0.001).

CONCLUSIONS

Achilles tendon disorders account for 3.8% of the total lay-off time and are more common in older players. Recurrence is common after Achilles tendinopathies and the reinjury risk is higher after short recovery periods.

Lower injury rates for newcomers to professional soccer: a prospective cohort study over 9 consecutive seasons

BACKGROUND

No study has investigated whether newcomers to professional soccer have a different injury rate than established players.

PURPOSE

The primary objective was to investigate whether being a newcomer to professional soccer influences injury rates. The secondary objective was to evaluate whether playing position and player age influence injury rates.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Twenty-six soccer clubs, with 1401 players, were followed prospectively over 9 consecutive seasons between 2001 and 2010. Club medical staff recorded time-loss injuries and soccer exposure on an individual level. Cox regression analyses were used to evaluate associations between time-loss injuries and time in professional soccer, playing position, and age.

RESULTS

In total, 6140 injuries and 797,389 hours of exposure were registered. A decreased general injury rate was observed for newcomers (n = 116) compared with established players (n = 3091) (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.61-0.99). In contrast, newcomers had a higher rate of fractures (rate ratio [RR], 1.77; 95% CI, 1.05-2.97), especially stress-related bone injuries (RR, 2.68; 95% CI, 1.08-6.69). Using goalkeepers as a reference, all outfield playing positions had significantly higher adjusted injury rates: defenders with an HR of 1.91 (95% CI, 1.64-2.24), midfielders with an HR of 1.78 (95% CI, 1.53-2.07), and forwards with an HR of 1.82 (95% CI, 1.55-2.14). Using players aged ≤21 years as a reference, the overall adjusted injury rate increased with age, with a peak injury rate among players aged 29 to 30 years (HR, 1.44; 95% CI, 1.24-1.68).

CONCLUSION

Newcomers to professional soccer had a lower general injury rate than established players but a higher rate of stress-related bone injuries. Being a goalkeeper was associated with lower injury rates than all outfield playing positions. Injury rates increased with age, a pattern that persisted after adjusting for playing position and match exposure.