Diagnostic Imaging in the Evaluation of Leg Pain in Athletes

Comparison of Ultrasonography to MRI in the Diagnosis of Lower Extremity Bone Stress Injuries: A Prospective Cohort Study

OBJECTIVE

To determine the sensitivity and specificity of ultrasound imaging (USI) compared to the reference-standard of MRI in the diagnosis of bone stress injury (BSI).

METHODS

A prospective blinded cohort study was conducted. Thirty seven patients who presented to an academic sports medicine clinic from 2016 to 2020 with suspected lower-extremity BSI on clinical exam underwent both magnetic resonance imaging (MRI) and USI. Participant characteristics were collected including age, gender and sport. Exclusion criteria included contraindication for dedicated MRI, traumatic fracture, or severe tendon or ligamentous injury. The primary outcome measure was BSI diagnosis by USI. An 8-point assessment system was utilized on USI for diagnosis of BSI, and the Fredericson and Nattiv²² criteria were applied to classify MRI findings.

RESULTS

Thirty seven participants who met study criteria were consented to participate. All participants completed baseline measures. Using MRI, there were 30 (81%) athletes with a positive and seven participants with a negative BSI diagnosis. The most common BSIs in the study were in the metatarsal (54%) and tibia (32%). Compared to MRI, USI demonstrated 0.80 sensitivity (95% confidence interval [CI], 0.61-0.92) and 0.71 specificity (95% CI, 0.29-0.96) in detecting BSI, with a positive predictive value of 0.92 (95% CI, 0.75-0.99) and negative predictive value of 0.45 (95% CI, 0.17-0.77).

CONCLUSIONS

USI is a potentially useful point-of-care tool for practicing sports medicine providers to combine with their clinical evaluation in the diagnosis of BSIs. Further research is ongoing to determine the role of USI in follow-up care and return-to-play protocols.

The Role of Magnetic Resonance in the Diagnosis of Chronic Exertional Compartment Syndrome

Chronic compartment syndrome is a common and often underdiagnosed exercise-induced condition, accounting on average for a quarter of cases of chronic exertional pain in the leg, second only to the fracture/tibial stress syndrome spectrum. It traditionally occurs in young runner athletes, although more recent studies have demonstrated a considerable prevalence in low-performance practitioners of physical activity, even in middle-aged or elderly patients. The list of differential diagnoses is extensive, and sometimes it is difficult to distinguish them only by the clinical data, and subsidiary examinations are required. The diagnosis is classically made by the clinical picture, by exclusion of the differential diagnoses, and through the measurement of the intracompartmental pressure. Although needle manometry is considered the gold standard in the diagnosis, its use is not universally accepted, since there are some important limitations, apart from the restricted availability of the needle equipment in Brazil. New protocols of manometry have recently been proposed to overcome the deficiency of the traditional ones, and some of them recommend the systematic use of magnetic resonance imaging (MRI) in the exclusion of differential diagnoses. The use of post-effort liquid-sensitive MRI sequences is a good noninvasive option instead of needle manometry in the diagnosis of chronic compartment syndrome, since the increase in post-exercise signal intensity is statistically significant when compared with manometry pressure values in asymptomatic patients and in those with the syndrome; hence, the test can be used in the diagnostic criteria. The definitive treatment is fasciotomy, although there are less effective alternatives.

Isolated Tearing and Avulsion of the Distal Biceps Femoris Tendon During Sporting Activities: A Systematic Review

Background:

Isolated tearing and avulsions of the distal biceps femoris sustained during sporting activities are uncommon.

Purpose:

To systematically review the literature to identify distal biceps femoris tears and avulsions experienced during sporting activities to determine injury prevalence, sporting activities/mechanisms, management, and time to return to sport.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was conducted investigating studies published between January 1970 and December 2017 that reported on athletes sustaining tears and avulsions of the distal biceps femoris during sporting activity. The review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and used the PubMed, Biosis Previews, SPORTDiscus, PEDro, and EMBASE databases. Inclusion criteria were studies reporting on (1) partial or complete tears and avulsions of the distal biceps femoris with documented sporting activity causing injury, (2) injury management (operative vs nonoperative), and (3) patient outcome. Exclusion criteria consisted of studies reporting on (1) distal biceps femoris injuries without tearing, (2) injuries secondary to nonsporting activities (mechanical falls, trauma), (3) concomitant injuries to adjacent structures about the knee, and (4) studies not reporting injury management or patient outcomes. Sporting activities, injury characteristics, management, and time to return to sport were analyzed.

Results:

A total of 22 athletes with isolated distal biceps femoris tears or avulsions were identified. Injuries were predominantly associated with noncontact knee hyperextension with concurrent hip flexion during soccer or track and field, most commonly isolated to the musculotendinous junction. Injuries were treated surgically in 91% (20/22) of athletes. Mean (±SD) overall time to return to sport was 4.9 ± 3.3 months, and for athletes who underwent operative repair, there were no significant postoperative differences based on injury location (musculotendinous junction vs avulsion, P = .25) or injury severity (partial vs complete injury, P = .13).

Conclusion:

Isolated distal biceps femoris injuries occurred primarily via noncontact mechanisms. The majority of cases were treated surgically, with successful return to sport at preinjury levels. No significant difference in return to sport was appreciated based on injury location or severity. Further studies are necessary to determine the impact of treatment method.

Popliteal Artery Entrapment or Chronic Exertional Compartment Syndrome?

Diagnosis of lower limb pain in an athlete can be a challenging task due to the variety of potential etiologies and ambiguity of presenting symptoms. Five of the most commonly encountered causes of limb pain in athletes are chronic exertional compartment syndrome (CECS), medial tibial stress syndrome (MTSS), tibial stress fractures, soleal sling syndrome, and popliteal artery entrapment syndrome (PAES). Of these, the least frequent but potentially most serious of the pathologies is PAES. With an incidence of less than 1% seen in living subject studies, the condition is rare. However, a missed diagnosis will likely lead to progression of the disease and potential for unnecessary invasive procedures (McAree et al. 2008). In this paper, we present a young athlete misdiagnosed and treated for chronic exertional compartment syndrome. In both descriptive and a quick-reference table format, we review current literature and discuss how best to distinguish functional PAES from other causes of activity-related leg pain.

Uncommon Diseases of The Popliteal Artery: A Pictorial Review

Uncommon diseases of the popliteal artery include cystic adventitial disease, popliteal artery entrapment syndrome (PAES) and popliteal artery aneurysm (PAA). Because all of these conditions may present with pain or intermittent claudication, imaging is crucial for differentiating them and directing management. Delayed diagnosis can lead to major complications, including acute limb ischemia. Our aim is to provide an illustrative overview of these conditions in order to make radiologists aware of them and avoid misdiagnosis for timely appropriate management.

Teaching Points

• Cystic adventitial disease diagnosis is based on evidence of cysts within artery walls.

• A variety of anatomic variations may result in PAES.

• PAES may be bilateral.

• PAA is most commonly encountered in men.

• Acute complications of PAA include acute thrombosis and distal embolization.

The injured runner

Running is often recommended by physicians to maintain a healthy lifestyle. As more individuals participate in running-related activities, clinicians must be increasingly aware of common injuries. Training errors leading to overuse are the most common underlying factors in most running-related injuries. Clinicians need to keep in mind that the presenting injury is frequently the result of an inability to compensate for a primary dysfunction at another site. Although imaging may be helpful in differentiating among diagnoses with similar clinical presentations, a detailed history and physical examination are essential in making a correct diagnosis.

Evaluation and management of hamstring injuries

Muscle injuries are the most common injuries in sports, with hamstring injuries accounting for 29% of all injuries in athletes. These injuries lead to prolonged impairment and have a reinjury risk of 12% to 31%. They range from mild muscle damage without loss of structural integrity to complete muscle tearing with fiber disruption. Novel MRI scores are increasingly being used and allow a more precise prediction of return to sport. In this article, the authors review the history, mechanisms of injury, and classification systems for hamstring injuries as well as present the latest evidence related to the management of hamstring injuries, including intramuscular and both proximal and distal insertional injuries. Indications for surgical treatment of certain proximal and distal avulsions, biological augmentation to the nonoperative treatment of midsubstance injuries, and advances in risk reduction and injury prevention are discussed.

Evaluation and treatment of biking and running injuries

Exercise is universally recognized as a key feature for maintaining good health. Likewise, lack of physical activity is a major risk factor for chronic disease and disability, an especially important fact considering our rapidly aging population. Biking and running are frequently recommended as forms of exercise. As more individuals participate in running-related and cycling-related activities, physicians must be increasingly aware of the common injuries encountered in these pursuits. This review focuses on the evaluation and management of common running-related and cycling-related injuries.