Stress fracture risk factors in soccer players: A systematic review

Abstract

Background: This study conducted a systematic review to evaluate stress fracture risk factors in soccer players, aiming to enhance injury prevention strategies.

Methods: We conducted a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, focusing on professional soccer players. Database searches (Medline, Scopus, CENTRAL, Embase, and Web of Science) used predefined terms in November 2024. Bias assessment employed Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument tools, and descriptive synthesis was used due to limited meta-analyzable data.

Results: Our systematic review analyzed 26 studies with 8514 participants. Young age was a risk factor in four studies, and female gender in one. High body mass index, increased training hours, competitions, and intense preseason training also raised risk. Anatomical factors included lower calcaneal pitch angle, wider medial malleolar slip angle, higher Talocalcaneal angle, and lower limb varus malalignment. Stress fractures were higher among midfielders in one study, while two others found no positional differences. Additional risks were elevated parathyroid hormone, higher bone-specific alkaline phosphatase, lower 25OH levels, fasting, and perceived stress from negative life events.

Conclusions: Soccer players face a heightened risk of stress fractures due to the repetitive forces involved in the sport, a significant concern given its global popularity. Although this review identified several risk factors, ongoing controversies remain, primarily due to the limited number of studies and the complex, multifactorial nature of stress fractures.

Keywords: anatomical and physiological predictors; risk factors; soccer players; stress fracture; systematic review.

Figure 1.

PRISMA flow diagram of the screening and selection process.

Figure 2.

The medial malleolar slip angle (MMSA) was the angle between a line of the medial malleolar articular surface and a line perpendicular to the continuous line of the tibial plafond. The medial malleolar length (MML) was the perpendicular distance from the medial malleolar tip to the continuous line of the tibial plafond. The lateral malleolar length (LML) was the perpendicular distance from the lateral malleolar tip to the continuous line of the tibial plafond. The talar distance (TD) was the length of the talar dome. Reprinted from Kizaki et al^[17^] with permission.

Figure 3.

(A) fifth metatarsophalangeal (MTP-5) angle: the angle subtended by the axes of the proximal phalanx and fifth metatarsal. (B) fourth-fifth intermetatarsal angle (IMA4-5): the angle subtended by the intersecting axes of the fourth and fifth metatarsals. (C) fifth metatarsal lateral deviation (MT5-LD) angle: the angle created by a line bisecting the midpoint of the articular surface of the head and the neck of the fifth metatarsal and line adjacent and parallel to the medial surface of the proximal metatarsal. Reprinted from Lee et al^[25^] with permission.

Figure 4.

(A) Talo first metatarsal (T-MT1) angle: the angle created between the bisection of the first metatarsal and a line perpendicular to a line connecting the anterior-dorsal and anterior-plantar extremes of the talar head. Positive when the talus was plantarflexed with respect to the first metatarsal. (B) Talocalcaneal (TC) angle: the angle formed by a line perpendicular to a line connecting the anterior-dorsal and anterior-plantar extremes of the talar head and a line from the most anterior-plantar point of the calcaneal tubercle to the most anterior-plantar point of the calcaneus at the calcaneocuboid joint. (C) Calcaneal pitch (CP) angle: the angle created between the floor and a line from the most anterior plantar point of the calcaneal tubercle to the most anterior plantar point of the calcaneus at the calcaneocuboid joint. Reprinted from Lee et al^[25^] with permission.

Figure 5.

Weightbearing dorsoplantar and lateral foot radiography showing the Jones fracture group and the control group. Each point of measurement in the mapping system was plotted. Reprinted from Fujitaka et al^[6^] with permission.