Baseline Musculoskeletal Imaging Abnormalities and Subsequent Injury in Asymptomatic Athletes: A Systematic Review and Exploratory Meta-Analysis
This systematic review and exploratory meta-analysis concludes that while baseline musculoskeletal imaging abnormalities in asymptomatic athletes, particularly on ultrasound of the Achilles and patellar tendons, predict a higher risk of subsequent same-region injury, the heterogeneity of findings suggests these results should guide monitoring and load management rather than serve as sole indications for restriction or invasive treatment.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
In the world of competitive sports, the line between a body that is adapting to extreme stress and one that is on the verge of breaking is often invisible to the naked eye. Coaches and medical teams increasingly rely on advanced imaging, such as magnetic resonance imaging and ultrasound, to peer inside the muscles, tendons, and bones of athletes who feel perfectly fine. These scans can reveal subtle changes—like a tendon that has thickened or a ligament that looks slightly frayed—that do not cause pain or limit movement at the moment of the scan. The central question for sports medicine has long been whether these silent, hidden changes are merely signs of a body getting stronger, or if they serve as an early warning system for a future injury. If a scan shows a flaw in an athlete who is currently pain-free, does that flaw predict a painful injury later, or is it just a normal variation that requires no action?
A new systematic review by researchers from the American Canadian School of Medicine, Yale University, and Desert Regional Medical Center set out to answer this question by gathering and analyzing data from studies that followed asymptomatic athletes over time. The team looked at research where healthy athletes underwent imaging before their season or training cycle and were then monitored to see if they eventually developed pain or injury in the exact same area that was scanned. By focusing only on athletes who had no symptoms at the start, the researchers could determine if the images themselves held any power to predict the future. They examined a wide range of sports and body parts, from the shoulders of professional baseball pitchers to the feet of ballet dancers, but their most significant findings emerged from a specific set of lower-body tendons.
The researchers found that for certain parts of the body, a silent abnormality on a scan does indeed signal a higher risk of future trouble, but the strength of this signal depends heavily on what is being looked at and how the image was taken. The most consistent evidence came from ultrasound scans of the Achilles tendon and the patellar tendon, which connects the kneecap to the shin. In studies involving collegiate athletes, those who had an abnormal ultrasound reading in these tendons were far more likely to suffer a time-loss injury later on compared to those with normal scans. The risk was particularly high for the Achilles tendon, where an abnormal scan was associated with an adjusted risk ratio of 19.2, while the patellar tendon showed an adjusted risk ratio of 10.7. These findings were strongest in the collegiate cohort; however, data from recreational runners showed a different picture for the patellar tendon, where the risk increase was not statistically significant, and results for younger athletes were less consistent or based on smaller numbers.
However, the story changes when looking at other body parts or different types of imaging. When the researchers examined magnetic resonance imaging, or MRI, scans of the shoulders in professional baseball pitchers or the feet and ankles of professional dancers, the results were much less clear. In these groups, it was very common to find structural oddities on the scans, yet these findings did not reliably predict who would get hurt. For example, in a group of professional dancers, almost every foot and ankle showed some kind of abnormality on an MRI, but only a tiny fraction of those dancers actually went on to suffer an injury that could be traced back to those specific findings. This suggests that for complex areas like the shoulder or the foot, a scan showing a change does not necessarily mean an injury is coming; the body may simply be adapting to the demands of the sport in a way that looks unusual on a picture but functions perfectly well in reality.
The review also highlighted a specific risk for young baseball players. In this group, ultrasound scans of the inner elbow showed that players with certain abnormalities in the growth area of the bone were 2.42 times as likely to develop a throwing-related injury compared to those without the finding. This points to a different kind of risk, likely related to how the body handles stress while still growing, rather than the wear and tear seen in adult tendons. Yet, even here, the evidence was not as robust as it was for the lower-leg tendons, largely because the studies involved smaller numbers of athletes and focused on specific types of injuries.
The researchers were careful to emphasize that while these imaging findings identify groups of athletes at higher risk, they are not a crystal ball. The data showed that many athletes with abnormal scans never developed pain, and many who got injured had normal scans to begin with. The high risk ratios found in the studies do not mean that an abnormal scan guarantees an injury, nor does a normal scan guarantee safety. Instead, the findings suggest that these images should be used as one piece of a larger puzzle. For a coach or doctor, seeing an abnormality on a scan of an Achilles or patellar tendon should prompt a closer look at the athlete's training load and a plan for monitoring, rather than an immediate decision to stop the athlete from playing or to perform surgery. The goal is to use the scan to guide smarter management of the athlete's workload, recognizing that the body's silent changes are often a signal to pay attention, not a command to stop.
Ultimately, this review clarifies that the value of preseason imaging depends entirely on the context. For the Achilles and patellar tendons, ultrasound has proven to be a useful tool for spotting athletes who are walking a tighter line between adaptation and injury, particularly in collegiate populations. For other areas, like the shoulder or the foot, the images often show more noise than signal, revealing changes that are common in healthy, high-performing bodies. The takeaway for the sports world is that an image alone cannot tell the whole story of an athlete's health. It is a snapshot of a structure, not a prediction of a career. The most effective approach remains a combination of imaging, careful observation of symptoms, and a deep understanding of the loads an athlete is placing on their body, ensuring that the technology serves to inform decisions rather than dictate them.
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