Rectus Femoris Scars on Ultrasound: What Do They Mean for Your Team?
By Carlos Jimenez, DPT, RMSK, CPSS | Pura Health
During preseason assessment of a 25-player squad, you identify a rectus femoris scar in an athlete who recalls no previous injury. Does that finding change the player’s injury risk or simply provide information worth exploring?
A prospective study examined this question. Its findings suggest that ultrasound may complement injury history, particularly when scarring involves a tendon or aponeurosis. But identifying a scar is not the same as predicting an injury.
What Did the Researchers Find?
Magistrali and colleagues followed 176 male football players from one professional club’s youth and second teams across two seasons, representing 262 player-seasons.
Players underwent bilateral rectus femoris ultrasound assessment, followed by recording of football exposure and subsequent non-contact time-loss muscle injuries.
Among the 43 players with ultrasound-detected scars, 51% did not recall a previous rectus femoris injury. Conversely, seven players reported a previous RF injury but had no detectable scar. Imaging and history therefore provided different, potentially complementary information.
Look Beyond “Scar Present”
The researchers described scars as irregular echogenic areas, sometimes accompanied by a hypoechoic halo. Abnormalities were assessed in two perpendicular planes, with documentation of dimensions and tendon or aponeurosis involvement.
MT scars involved a tendon and/or aponeurosis, including structures such as the central aponeurosis. Non-MT scars did not involve those structures.
Within the scar-positive subgroup, muscle injury incidence was:
MT scars: 4.45 injuries per 1,000 player-hoursNon-MT scars: 2.44 injuries per 1,000 player-hours
The incidence rate ratio was 1.83 (95% CI 1.01–3.30; p = 0.047) approximately an 83% higher observed injury event rate in the MT group. Scar size and number were not significantly associated with injury incidence in this cohort.
Importantly, these were injuries across muscle groups, not just reinjuries to the scarred rectus femoris. An 83% higher rate does not mean an athlete has an 83% chance of injury.
The Important Qualification: Age and Injury History Matter
After adjustment for age and previous muscle injury, the association between any RF scar and injury incidence was no longer statistically significant.
For MT scars, a separate whole-cohort comparison against both scar-free players and players with non-MT scars showed the incidence rate ratio fall from 2.11 unadjusted to 1.42 adjusted (95% CI 0.96–2.09; p = 0.078). This is a different comparison from the within-scar estimate of 1.83.
MT scars remained associated with a shorter time to first muscle injury in the adjusted analysis: hazard ratio 1.69 (95% CI 1.07–2.67). However, this does not establish when or whether an individual athlete will be injured. The authors describe the findings as exploratory.
What Could This Look Like in a 25-Player Squad?
Approximately 24% of player-seasons had an RF scar, and 9.5% had an MT scar. Applying those proportions to a hypothetical 25-player squad would mean approximately six players with RF scars, including two or three with MT involvement. This illustrates the study’s distribution; it is not an expected finding in every team.
To make the injury rates tangible, suppose three players each accumulate 250 hours of football exposure during a season. That gives 750 combined player-hours. The 250-hour figure is an illustrative assumption, not the study’s reported seasonal average.
Applying the published rates to that exposure gives:
MT-scar rate: 4.45 × 750 ÷ 1,000 ≈ 3.3 injury events
Non-MT-scar rate: 2.44 × 750 ÷ 1,000 ≈ 1.8 injury events
These are group-level calculations, not forecasts for three specific players. One athlete can sustain multiple injuries. The difference also does not represent injuries a team could necessarily prevent through screening or scar treatment.
The team-level question is therefore:
What additional information does this finding provide about this player not which player is guaranteed to get injured?
How Should Clinicians Use This Information?
A practical interpretation not a management protocol tested by this study is to use an unexpected scar to revisit injury history and document the tissue more precisely.
Rather than recording only “RF scar,” describe its location, dimensions, appearance in orthogonal planes, and relationship to the tendon or central aponeurosis. Then interpret that finding alongside the athlete’s current symptoms, strength, function, and football demands.
This study alone does not justify reducing training, delaying return to sport, or treating an asymptomatic scar to prevent future injury. It involved one club, a predominantly young male population, and only 25 MT-scar-positive player-seasons. It did not test whether ultrasound-guided management prevented injuries, and the authors caution against translating these results into formal recommendations.
The Clinical Takeaway
Rectus femoris scarring may add useful structural information when injury history is incomplete. Tendon and aponeurosis involvement deserves careful characterization, but its additional predictive value remains uncertain.
Document the tissue. Understand the history. Assess the athlete. Do not turn a scar into a forecast.
Develop your team’s MSK ultrasound skills with Pura Health. Explore lower-extremity training focused on image acquisition, tissue characterization, and clinical reasoning.
Reference: Magistrali M, et al. Rectus femoris scarring as a marker of greater muscle injury risk in young football players: a prospective observational study. Science and Medicine in Football. 2026. doi:10.1080/24733938.2026.2726162.
Ultrasound image credit: Figure 2, Magistrali et al. (2026). © The Authors, CC BY 4.0. Graphs present data from Tables 2 and 4.
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