Page 31 - ISAKOS 2019 Newsletter Volume 1

Stress Fractures in Footballers
Stress fractures can be divided, according to bone quality and load, into (1) fatigue fractures (those resulting from increased load and/or cyclic forces on normal bone, for example, as the result of a high volume of exercises in a short period of time) and (2) insufficiency fractures (those produced by normal load within weakened bones, for example, in patients with osteoporosis or osteomalacia).
Bone is a dynamic tissue, and its turnover cycle of remodeling and mineralization requires a period of 3 to 4 months. A stress fracture is a failure of bone resistance and remodeling in response to strain forces (known as “stress”). Such stress can be the result of repetitive loading and/or overloading associated with training parameters such as volume, intensity, playing surface, or inadequate recovery time. However, stress fractures are not only due to bone pathophysiology and biomechanical factors; hormonal, nutritional, genetic, and other intrinsic and extrinsic factors are involved as well (Table I).
Table I Intrinsic and Extrinsic Risk Factors for Stress Fractures2
Introduction
Gonzalo Samitier, MD, PhD
Hospital General de Villalba Madrid, SPAIN
Gustavo Vinagre, MD, PhD
Porto, PORTUGAL
André Pedrinelli, MD
Hospital das Clínicas FMUSP Sao Paulo, BRAZIL
Lúcio Ernlund, MD Instituto de Joelho e Ombro Curitiba – BRAZIL
Intrinsic Factors
• Female gender (hypoestrogenic state/ menstrual dysfunction/ female athlete triad)
• Age (in males, incidence decreases after 17 years of age; in females, it increases after menarche)
• Low BMI (<19)
• Low physical activity
• Anatomic variations (lower extremities malalignment, leg length discrepancy, pes planus/cavus)
Diagnosis
Clinical Presentation
Extrinsic Factors
• Training schedule changes • Inadequate/changing
footwear
• High-volume and intensity training
• Hard surfaces
• Long-distance running • Alcohol use
• Smoking
• Low vitamin D
A stress fracture is a partial or complete disruption of bone continuity and is among the most common overuse injuries in physically active individuals1. Stress fractures represent 0.5% of all injuries in elite male football (soccer) players and 13.6% of those in elite female football players. Ekstrand et al.1 in a study of professional football players in the UEFA League, reported that players sustained an average of 2.0 injuries of any kind per season.
Mechanism of Injury (Pathophysiology)
Although the exact pathophysiology of stress fractures is unknown, it can be understood as an imbalance between the strength of the bone itself (bone resistance) and chronic mechanical overload (due to forces of tension, compression, and/or impact) exceeding the range of bone elasticity.
A detailed history and focused physical examination with a presumptive clinical suspicion are key for a correct, non- delayed diagnosis of a stress fracture.
Most patients report an insidious onset of pain that is aggravated by weight-bearing or repeated physical activities and is relieved by rest. However, many athletes with stress fractures can be asymptomatic. Usually, there is no history of trauma. It is critical to have a high index of suspicion regarding the presence of predisposing risk factors as shown in Table I.
CURRENT CONCEPTS
ISAKOS NEWSLETTER 2019: VOLUME I 29