ABSTRACT
BACKGROUND: Fibula stress fractures are moderately common injuries among athletes and military recruits. Most of the available data for treatment come from case reports with a limited number of large studies. This systematic review aims to evaluate and present the current literature on fibula stress fractures to help set evidence-based goals and establish realistic expectations for return to activity and sport in injured patients. METHODS: Systematic literature search using 3 databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol and the Cochrane Handbook guidelines were followed. The terms "fibula stress fracture" or "fibular stress fracture" were searched. Date range for inclusion was 2010-2022. Pediatric, non-English, lack of full text available, and studies lacking differentiating fibula stress fracture versus other types of fractures in their data were excluded. RESULTS: A total of 3 studies with 10 987 subjects were included. Among 521 stress fractures in all 3 studies, there were 45 (8.6% of all fractures) cases involving the fibula. All fibular stress fractures healed successfully with nonoperative measures and non-weight-bearing precautions, on average, by 7 weeks and patients resumed activity, on average, by 9 weeks. Among the 3 studies, there were no reported cases of nonunion or delayed union. CONCLUSION: This review found that fibula stress fractures have a relatively moderate incidence among stress fracture injuries with a frequency up to 8.6%. Despite this high number, there is sufficient healing in fibula stress fractures when managed nonoperatively with activity modification in a weight-bearing foot to allow for resumption of baseline activities, on average, by 9 weeks. This review can be used to help set evidence-based goals and establish realistic expectations for return to activity and sport in patients who suffer from fibula stress fractures. LEVELS OF EVIDENCE: Level II.
ABSTRACT
BACKGROUND: Animal models of skeletal muscle damage and repair demonstrate that therapeutic ultrasound (TUS) enhances muscle force recovery after damage, increases satellite cell proliferation, and decreases insulin-like growth factor (IGF)-1 splice variant (mechano growth factor) gene expression. However, these effects have not been verified in humans. PURPOSE: This study was undertaken to examine the 3 known splice variants of the IGF-1 gene in human skeletal muscle after damage and TUS treatment. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen healthy men (18-29 years of age), physically active, were randomized to either a control (CON) or experimental group (EXP). The EXP group underwent 200 lengthening contractions (muscle damage) of the quadriceps of both legs, 48 hours before TUS. Both groups received TUS, delivered for 10 minutes on a standardized area of the vastus lateralis of only 1 leg (1.0 MHz, 1.5 W/cm(2)). Bilateral muscle biopsy samples were taken from all participants, 6 hours after TUS. Total RNA was extracted, and quantitative real-time polymerase chain reaction conducted for each IGF-1 splice variant. RESULTS: Muscle damage was confirmed by a decrease in the isometric peak torque and increase in creatine kinase activity levels 48 hours after damage (P < .01). After muscle damage, gene expression of total IGF-1 and 2 IGF-1 splice variants increased. Therapeutic ultrasound induced significant increase in IGF-1Eb gene expression in undamaged muscle (1.4 ± 0.2-fold, P < 0.01). In damaged skeletal muscle, no significant change in gene expression attributable to TUS was determined. CONCLUSION: Insulin-like growth factor-1 splice variants are differentially regulated in human skeletal muscle in response to exercise-induced muscle damage and TUS treatment. A single treatment of TUS in damaged muscle induces no change in the gene expression of the 3 IGF-1 splice variants in humans. In contrast, in undamaged skeletal muscle, TUS significantly increased IGF-1Eb splice variant gene expression. CLINICAL RELEVANCE: These findings suggest that TUS may have additional therapeutic uses beyond its current common practice but may not be effective for muscle injury treatment in a young, healthy population.
