Ultrasound in Trauma and Other Acute Conditions in Sports, Part I

Abstract

The utility of ultrasound in sports medicine is improving the sports medicine physician's ability to rapidly diagnose and treat a multitude of sports related pathologies. In this article, we clearly outline the current status of the evidence in support of using sports ultrasound in the setting of acute abdominal and thoracic trauma, acute lung illness, limited cardiac evaluation of a collapsed athlete, volume status assessment, and fracture evaluation.

Introduction

The use of point-of-care ultrasound (POCUS), portable ultrasound used at the bedside for a wide variety of indications, is becoming increasingly common across many medical specialties. Emergency physicians (EPs) have been using POCUS for more than two decades in the acute setting for evaluation of emergent and urgent traumatic conditions such as intra-abdominal injury, pneumothorax, pulmonary edema, cardiac ultrasound, fractures, globe rupture, retinal detachment, as well as other acute conditions, such as deep venous thrombosis, dehydration, and cutaneous abscess. These applications used by EPs also may be appropriate for use by sports medicine physicians in the acute setting.

The term sports ultrasound (US) was introduced in the 2014 American Medical Society for Sports Medicine sports ultrasound curriculum for sports medicine physicians (¹) to incorporate both musculoskeletal (MSK) and non-MSK applications of sports US used by sports medicine physicians. Sports US training is a requirement of Accreditation Council for Graduate Medical Education-accredited sports medicine fellowships; however, this is often limited to MSK applications. It is now recognized that the utility of sports US extends beyond these MSK applications and includes evaluation for trauma and other acute conditions associated with sport and exercise. Sports US evaluations are most often performed to answer a specific clinical question, and there may be inherent limitations when performed in the field. The need for further imaging and involvement of other medical imaging experts should be considered.

This article is part 1 of a two-part series providing a review of the literature for assessment of traumatic injuries and other acute conditions which may be encountered in sports medicine. Part 1 will review the use of US for evaluation of intraabdominal injury, pneumothorax, hemothorax, pulmonary edema, limited cardiac assessment, dehydration, and fractures. Part 2 will review acute ocular injury, evaluation of elevated intracranial pressures, cellulitis, deep venous thrombosis, and lymphadenopathy.

I. Ultrasound for Abdominal Trauma

Focused Assessment with Sonography in Trauma (FAST) is a noninvasive US assessment to rapidly identify free pericardial, intraperitoneal, and pelvic free fluid (i.e., blood) after trauma. Blunt abdominal injury is a common concern for contact (football, rugby, lacrosse), airborne (gymnastics, diving, pole-vaulting, climbing), and high-impact (skiing, snowboarding, equestrian, rodeo or motorized sport) athletes. Patients may present with severe abdominal pain, with or without hypotension. The FAST examination may be applied in the sports medicine setting to quickly evaluate for intraabdominal bleeding after abdominal trauma and thus aid in medical decision making and disposition of the injured athlete. Earlier diagnosis enables prompt intervention, less complications, and better patient outcomes. Furthermore, the FAST protocol has been extended to include anterior thoracic evaluation for pneumothorax, termed the “E-FAST” examination. The use of sports US to detect pneumothorax, pericardial, and pleural effusion will be discussed in later sections.

FAST Examination Indications

• - Blunt or penetrating thoracoabdominal trauma (²)
• - Trauma in pregnancy
• - Undifferentiated hypotension

FAST Examination Technique

Transducer: Curvilinear or Phased Array transducer

Patient Position: supine

Transducer Position: four standard views

• - Right upper quadrant (RUQ), hepatorenal recess (Morison's pouch)
• - Left upper quadrant (LUQ), perisplenic recess
• - Suprapubic, retrovesicular (male) or retrouterine (female) pouch
• - Subxiphoid, pericardial space

(See Figs. 1A–D here https://links.lww.com/CSMR/A67, https://links.lww.com/CSMR/A68, https://links.lww.com/CSMR/A69, https://links.lww.com/CSMR/A70)

Key Findings: Absence or presence of free fluid.

(See Figs. 2A–D here https://links.lww.com/CSMR/A71, https://links.lww.com/CSMR/A72, https://links.lww.com/CSMR/A73, https://links.lww.com/CSMR/A74)

Effectiveness of FAST Examination as a Screening Tool

There is a vast body of data on the efficacy of FAST examination in various clinical settings, patient injury severities, and performed by providers of various specialties and experience levels. This is summarized in Table 1. It is broadly accepted that FAST is an excellent screening tool in the hands of an experienced examiner and is a component of the Advanced Trauma Life Support (¹²) protocol as an adjunct to the primary survey (¹³). Overall, the use of US to detect intraperitoneal free fluid or pericardial effusion has a high specificity; however, a lower sensitivity. Data suggest that the examination is less reliable at low volumes of fluid, with a mean of 157 mL required in one study (¹⁴) and as high as 619 mL in another (¹⁵) for detection of intraperitoneal free fluid, depending on the region visualized. Serial FAST examinations have been shown to significantly increase the sensitivity of these studies (¹⁶), especially if the initial examination was completed early in the patient's presentation and prior to the accumulation of enough blood in the abdomen to be reliably detected. Thus, the FAST examination should be used as a screening assessment and not in place of a formal emergency department (ED) evaluation when indicated by clinical judgment.

Table 1 - Accuracy of FAST and E-FAST examinations for evaluation and detection of hemoperitoneum.

Year	Author	Examination	Sens (%)	Spec (%)	PPV (%)	NPV (%)	Accuracy (%)
2019	Lee et al. (3)	FAST	92	99	91	99
2019	Netherton et al. (4)	EFAST	74	98
2018	Akoglu et al. (5)	EFAST	43	98			71
2018	Samuel et al. (6)	EFAST	90	99	95	98	98
2018	Waheed et al. (7)	FAST	76	84			79
2017	Dammers et al. (8)	FAST	67	99
2014	Verbeek et al. (9)	FAST	64	94	84	83
2014	Arhami et al. (10)	FAST	80	95	57	98	94
2010	Becker et al. (11)	FAST	75	98	88	95	95

Boxes left blank were not reported in the study.

Sens, sensitivity; Spec, specificity; PPV, positive predictive value; NPV, negative predictive value.

RUSH Examination

More recently, critical care and emergency medicine literature has described the Rapid Ultrasound in Shock and Hypotension (RUSH) examination, a more extensive evaluation for the undifferentiated patient with hypotension and shock. It includes a more extensive cardiopulmonary assessment and volume status evaluation in addition to the screening test for pericardial effusion and hemoperitoneum from the FAST examination. The RUSH examination combines the standard images obtained in the FAST examination (discussed above) with additional images of the inferior vena cava (IVC), aorta, and thorax. Using IVC diameter to assess volume status will be discussed in further detail below. A common approach refers to “the pump” (heart), “the tank” (IVC/intravascular volume) and “the pipes” (arterial/venous vessels) as the major steps in the RUSH examination and evaluation of shock. The mnemonic “HI-MAP” (heart, IVC, Morison's pouch/splenorenal/bladder, aorta, pneumothorax) is utilized to facilitate performing the complete examination in consistent sequence. This entire examination can be completed in less than 2 min.

RUSH Examination Indications:

• - Hypotension/shock of unclear etiology

RUSH Examination Technique:

Transducer: phased array, curvilinear, and option of linear transducer

Patient position: supine

Transducer choice and orientation varies with desired view:

Phased Array Transducer:

• - heart: parasternal long, parasternal short, subxiphoid, apical four-chamber views
• - IVC

Curvilinear Transducer:

• - Morison's/FAST abdominal
• - pelvic views with thorax/diaphragm views
• - aorta

Linear High-Frequency Transducer:

• - pneumothorax (lung windows)

(See Figs. 3A–F here https://links.lww.com/CSMR/A75, https://links.lww.com/CSMR/A76, https://links.lww.com/CSMR/A77, https://links.lww.com/CSMR/A78, https://links.lww.com/CSMR/A79, https://links.lww.com/CSMR/A80)

Key Findings: cardiac motility/effusion, absence of lung slide, IVC diameter/respiratory variability, presence of free fluid

(See Figs. 4A–F here https://links.lww.com/CSMR/A82, https://links.lww.com/CSMR/A83, https://links.lww.com/CSMR/A84, https://links.lww.com/CSMR/A85, https://links.lww.com/CSMR/A86, https://links.lww.com/CSMR/A87)

Effectiveness of the RUSH Examination as a Screening Tool

The RUSH technique is a newer protocol utilized by critical care and EPs, and the data of its efficacy are growing. The results, summarized in Table 2, outline the sensitivity and specificities of RUSH examination compared with computed tomography (CT) scan criterion standard for patients with shock. The RUSH protocol performs relatively well across all shock types.

Table 2 - Accuracy of RUSH examination for evaluation and diagnosis of shock.

Year	Author	Examination	Type of Shock	Sens (%)	Spec (%)	PPV (%)	NPV (%)
2018	Elbaih et al. (17)	RUSH	Hypovolemic	92	92	95	87
			Cardiogenic	100	99	91	100
			Obstructive	93	98	87	99
			Distributive	92	97	79	99
2015	Ghane et al. (18)	RUSH	Hypovolemic	100	96	89	100
			Cardiogenic	90	98	95	97
			Obstructive	91	98	91	98
			Distributive	73	100	100	95
			Mixed	64	98	88	93
2015	Bagheri-Hariri et al. (19)	RUSH	Hypovolemic	100	73	82	100
			Cardiogenic	60	100	100	91
			Obstructive	75	100	100	96
			Distributive	100	100	100	100

Boxes left blank were not reported in the study.

II. Ultrasound for Thoracic Trauma and Acute Lung Illness

In the setting of thoracoabdominal trauma, bedside US is often used to evaluate for pneumothorax or hemothorax in conjunction with the traditional FAST examination and is called the extended FAST (E-FAST) examination (²⁰). In fact, US has been shown to have higher sensitivity (^21,22) than standard supine AP chest radiographs at detecting pneumothorax and may even be able to replace routine chest radiographs after blunt trauma (²³). This can apply similarly to sports US evaluation for patients with dyspnea, chest pain, or hypoxia where specific concerns regarding pneumothorax, pulmonary edema, or hemothorax would be important to identify early. Sports US also can be used to evaluate for rib fractures in this scenario.

The Bedside Lung Ultrasound in Emergency (BLUE) Protocol has been described as a diagnostic tool in critically ill patients (²⁴). There are several studies applying this to the ED setting to categorize and diagnose etiologies of dyspnea including pulmonary edema, pneumonia, obstructive airway disease, pulmonary embolism, and pneumothorax. On-site at athletic events, the most useful application of this protocol would be to identify pneumothorax, hemothorax, and pulmonary edema.

Thoracic US Indications:

• - shortness of breath
• - chest pain
• - chest trauma
• - undifferentiated shock

Pneumothorax US technique:

Transducer: high-frequency linear array transducer

Patient position: supine/semirecumbent

Transducer position:

•  -Vertically oriented in a sagittal plane
•  -Three intercostal spaces at the midclavicular line at the highest point along the thorax

See Figure 3G here https://links.lww.com/CSMR/A81

Key Findings: Absence or presence of lung sliding

See Figures 4E–F here https://links.lww.com/CSMR/A86, https://links.lww.com/CSMR/A87

The examiner may visually observe the absence or presence of the lung pleura sliding by noting the normal “comet tail” or “shimmering” appearance, which is absent with pneumothorax. Pneumothorax also may be detected using the M mode setting to visualize the “barcode” appearance which lacks the transition to aerated lung represented the normal “sandy beach” sign (²⁵).

Hemothorax US Technique:

Transducer: high-frequency linear array transducer

Patient position: supine/semirecumbent

Transducer position: visualization of diaphragmatic recesses

•  -RUQ view
•  -LUQ view

Key Findings: intrathoracic free fluid (visually equivalent to pleural effusion) above diaphragm

The examiner should pay particular attention to the optimal visualization of the diaphragm and evaluation for peridiaphragmatic fluid in the pleural space, suggestive of effusion, or presumably blood in the acute traumatic setting.

Summarized below in Table 3 are the data for the recent studies elucidating the accuracy of bedside US for evaluation of hemothorax and pneumothorax.

Table 3 - Accuracy of ultrasound for evaluation and diagnosis of hemothorax and pneumothorax and other traumatic lung injury.

Year	Author	Pathology	Sens (%)	Spec (%)	PPV (%)	NPV (%)	Accuracy (%)
2019	Bekgoz et al. (24)	PTX	71	100
2019	Kozaci et al. (26)	SubQ Emph	56	95
		PTX	86	97
		HTX	45	98
		Pulm Cont	63	91
2019	Netherton et al. (4)	PTX	69	99
2018	Akoglu et al. (5)	PTX	75	99			87
		Pl Eff	100	100			100
2018	Patel et al. (27)	PTX/A profile	80	100			90
2016	Vafaei et al. (28)	PTX	84	98	96	91
		HTX	76	96	82	94
		Pulm Cont	69	92	81	87
2015	Soult et al. (23)	PTX	94	98	46	100
2008	Soldati et al. (29)	PTX	92	99	96	99
2008	Lichtenstein and Mezière (30)	PTX	88	100	100	99
2005	Blaivas et al. (21)	PTX	98	99	98.1	99

PTX, pneumothorax; HTX, hemothorax; SubQ Emph, subcutaneous emphysema; Pl Eff, pleural effusion; Pulm Cont, pulmonary contusion.

Boxes left blank were not reported in the study.

Pulmonary Edema

There also is increasing data on the use of ultrasound for monitoring altitude effects and pulmonary edema in high altitude athletes. Pulmonary edema produces an ultrasound artifact known as B lines.

B lines are a type of ring down ultrasound artifact that are produced when there is enough perialveolar fluid to produce a tetrahedron between air and water molecules. Various “lung profiles” have been described in association with pulmonary pathologies in respiratory failure, and there is a strong correlation between the presence of bilateral B lines with associated lung slide in the diagnosis of pulmonary edema, known as “B Profile” (³⁰).

Pulmonary Edema US Technique

Transducer: low-frequency curvilinear transducer or low-frequency phased array transducer

Patient position: supine/semirecumbent/upright

Transducer position:

•  -anterior chest view
•  -axillary view

(See Fig. 5 here https://links.lww.com/CSMR/A88)

Key Findings: greater than three B lines per intercostal space. These can be seen as echogenic “comet tails” vertically oriented in intercostal spaces, in both anterior and lateral chest views

(See Fig. 6 here https://links.lww.com/CSMR/A89)

When there are more than three B lines in a single intercostal space, this is consistent with increased interstitial pulmonary fluid and thus represents pulmonary edema. This could be extrapolated to the use of sports US at endurance events and other competitions at higher altitudes to identify exertional pulmonary edema. One study evaluated the incidence of subclinical pulmonary edema by serial arterial blood gases and comparative B line measurements on US in Himalaya trekkers. A total of 20 hikers ascended to 5160 m over 10 d and more than half developed increased B lines with altitude, which were negatively correlated with paO2s (³¹). Another study compared the use of US, CXR, and physical examination (moist rales on auscultation) in the detection of pulmonary edema and found lung US outperformed CXR and examination in sensitivity for pulmonary edema (as measured by presence of B lines) with US sensitivity of 98% compared to 93% and 81% for CXR and physical examination, respectively (³²). Further, US detection of pulmonary edema has a combined sensitivity of 97% and specificity of 98% from a recent meta-analysis and systematic review (³³).

It is worth highlighting that there is significant heterogeneity across the patient populations and conditions under which these data were obtained; however, the diagnostic utility of ultrasound in pulmonary edema applies across these populations, and similarly could be extrapolated to the athlete population.

Table 4 summarizes the primary data regarding US detection of pulmonary edema.

Table 4 - Accuracy of bedside US for evaluation and diagnosis of pulmonary edema.

Year	Author	Examination	Sens (%)	Spec (%)	PPV (%)	NPV (%)	Accuracy (%)
2019	Bekgoz et al. (24)	Pulmonary Edema	88	96
2019	Wooten et al. (34)	B profile	96
2018	Koh et al. (35)	BLUE protocol/B profile	71	81	73	80	77
2018	Patel et al. (27)	BLUE protocol/B profile	92	100
2018	Wang et al. (33)	B lines/all protocols	97	98
2018	Yang et al. (32)	B lines/B score	98	91	98	91
2015	Dexheimer Neto et al. (36)	BLUE protocol	85	87	80	91	84
2015	Pivetta et al. (37)	B lines	97	97
2013	Baker et al. (38)	Pulmonary edema	65	92			85
2011	Vitturi et al. (39)	B lines	97	79	79	97	87
2008	Lichtenstein and Mezière (30)	Pulmonary edema	97	95	87	99

Boxes left blank were not reported in the study.

III. Ultrasound for Cardiac Assessment

Another potential application of sports US is the performance of a limited cardiac ultrasound in the acute setting of an injured or collapsed athlete in extremis to rapidly answer several emergent questions regarding the hemodynamics, pathology and illness severity of a patient in real-time. While it is no substitute for a formal, comprehensive echocardiogram in the hands of a cardiologist, it may aid in evaluating gross cardiac function (^40,41). The American College of Emergency Physicians’ consensus statement on focused cardiac US (FOCUS) emphasizes the importance of FOCUS as a preliminary diagnostic tool in the time-sensitive evaluation of symptomatic patients in the emergent setting and outlines the goals of FOCUS including (⁴²):

Limited cardiac US Indications:

• - presence of pericardial effusion,
• - global cardiac systolic function,
• - marked right ventricular and left ventricular enlargement,
• - intravascular volume assessment.

Limited Cardiac US Technique:

Transducer: low-frequency phased-array transducer

Patient position: supine/left lateral decubitus

Transducer position: varies with each view

Four standard views:

•  -parasternal long axis
•  -parasternal short axis
•  -apical four-chamber
•  -subxiphoid (Four-chamber and short-axis views)

See Figures 3A–D here https://links.lww.com/CSMR/A75, https://links.lww.com/CSMR/A76, https://links.lww.com/CSMR/A77, https://links.lww.com/CSMR/A78

Key Findings

• - pericardial effusion,
• - hypokinesis,
• - poor contractility,
• - relative chamber size.

Pericardial Effusion

Evaluation of pericardial effusion in the acute traumatic and symptomatic patient is highly valuable in the emergent setting and early recognition can lead to lifesaving interventions. While recognition of tamponade is ultimately a clinical diagnosis (hypotension, tachycardia, pulsus paradoxus, and jugular venous distention), US is an important adjunct not only for diagnosis but also for treatment. It is important to remember that in a hemodynamically unstable trauma patient, the severity of hemodynamic compromise may be pronounced relative to a seemingly small-volume pericardial effusion or thrombus. Data summarized in Table 5 suggest that noncardiologist physicians can accurately assess for pericardial effusion, and ultrasound is the evaluation tool of choice in the acute setting.

Table 5 - Accuracy of US for evaluation and diagnosis of pericardial effusion.

Year	Author	Sens (%)	Spec (%)	PPV (%)	NPV (%)	Accuracy (%)
2019	Balderston et al. (43)	64	91	56	94
2019	Netherton et al. (4)	91	94
2017	Farsi et al. (44)	86	96	69	98	95
2005	Blaivas et al. (21)	73	44			30
2001	Mandavia et al. (45)	96	98			98

Boxes left blank were not reported in the study.

Global Systolic Function

To evaluate global cardiac function, it is important to evaluate multiple views, including parasternal, subxiphoid, and apical to assess cardiac contractility as a surrogate for cardiac output. Cardiac contractility is determined by the change in the volume of the left ventricle in systole and diastole. The goal of FOCUS is to assess global cardiac function qualitatively (normal, depressed, hyperdynamic, etc.) rather than quantitatively, with the overall goal of determining disposition and workup related to patient's symptoms or hemodynamics. In one prospective study by Moore et al. (⁴⁰) in 2002 comparing EPs to primary cardiologists, it was found that qualitative evaluation of ejection fraction (normal, decreased, severely decreased) by EPs after undergoing a 10-h observatory training period was sufficiently accurate (R = 0.84). Table 6 below summarizes primary data regarding assessment of gross cardiac function.

Table 6 - Accuracy of limited cardiac ultrasound for evaluation of gross cardiac function.

Year	Author	Sens (%)	Spec (%)	PPV (%)	NPV (%)	Accuracy (%)
2019	Balderston et al. (43)	80	78	54	92
2017	Farsi et al. (44)	89–100	87–100	80–100	89–100	92–100

Boxes left blank were not reported in the study.

IV. Ultrasound for Volume Assessment

An athlete's hydration status is a critical component of health and performance. For example, cramping, heat exhaustion, and heat stroke may all be related to inadequate hydration and can be life-threatening, especially if not recognized early. The POCUS evaluation is regularly utilized in evaluation of undifferentiated shock, or to assess the intravascular volume and potential fluid responsiveness of a hypotensive patient in the ED setting. It also makes sense to apply this to the acute sideline assessment of an ill, collapsed, or injured athlete to evaluate their volume status to guide the diagnosis and treatment.

Commonly cited measurements that have been found to correlate with intravascular volume status include measurements of IVC diameter and respiratory collapsibility. Generally speaking, IVC diameter decreases with inspiration and increases with Valsalva, and while considerable heterogeneity exists regarding the exact relationship between right atrial pressure and the behavior of the IVC, an IVC diameter <1.5 cm suggests volume depletion and IVC > 2.5 cm suggests volume overload (²). There are a significant number of studies evaluating hydration status in correlation with IVC diameter variation, also known as the IVC collapsibility index or caval index: (Caval index = (IVC_expiration − IVC_inspiration) / (IVC_expiration) × 100) (⁴⁶). Unfortunately, there is significant heterogeneity in these studies, and the majority of this data are derived from critically ill patients. These studies provide potential support for IVC measurements as a marker for volume status and could be applied to athletes with suspected volume depletion in the appropriate clinical settings. A study by Waterbrook et al. (⁴⁷) of preseason NCAA football players from 2015 evaluated the IVC diameter of players prepractice and postpractice and found statistically significant correlation with the players' percent weight loss during practice, suggesting correlation with hydration. Interestingly, Long et al's (⁴⁸) systematic review and meta-analysis did not find respiratory variation of the IVC to reliably predict fluid responsiveness in critically ill patients, a subgroup analysis in this study did find IVC diameter to be a promising predictor, similar to the study previously performed in NCAA athletes. Inferior vena cava measurements are likely most useful when evaluating for the extremes: complete collapse may suggest that the athlete can benefit from hydration, and if there is no collapsibility or if the IVC is plump, the athlete may not need additional hydration. Inferior vena cava evaluation also may be performed as a part of the RUSH examination or in conjunction with limited cardiac US (see previous sections for further discussion of these examinations).

IVC Assessment Technique:

Transducer: low-frequency curvilinear or phased array transducer

Patient position: supine

Transducer position: subxiphoid (most optimal [⁴⁹]) or subcostal view, sagittal plane

See Figure 3E here https://links.lww.com/CSMR/A79

Key finding:

•  -Presence and degree of anterior-posterior collapse / variability of IVC diameter with respiration

See Figures 4C–D here https://links.lww.com/CSMR/A84, https://links.lww.com/CSMR/A85

The atria can be visualized and traced inferiorly, down to the perihepatic IVC where most reliable measurements can be made. When measured 3 cm to 5 cm inferior to the right atrium (1 cm to 2 cm below junction of hepatic vein) the normal IVC is approximately 1.5 cm to 2.5 cm in diameter.

Inferior vena cava measurement may be used as a tool to evaluate hydration status in athletes. Its accuracy, however, especially in well athletes, is still not fully known. Table 7 summarizes the current data on the accuracy of IVC collapsibility to predict fluid responsiveness. Clinical context should always be taken into consideration when using this technique of volume assessment and making treatment decisions.

Table 7 - Accuracy of IVC collapsibility to predict fluid responsiveness.

Year	Author	Sens (%)	Spec (%)	PPV (%)	NPV (%)
2020	Orso et al. (46)	71	75
2018	Long et al. (50)	44	33
2017	Corl et al. (51)	87	81	82	86
2017	Long et al. (48)	63	73
2017	Preau et al. (52)	84	90
2016	Theerawit et al. (53)	75	77
2016	Zhao and Wang (54)	100	100
2014	Zhang et al. (55)	76	86

Boxes left blank were not reported in the study.

V. Ultrasound for Fracture Assessment

Ultrasound has been increasingly recognized as a reliable, safe, and rapid evaluation for fracture detection by identifying notable discontinuity of the hyperechoic bony cortex. Although MRI, CT, and radiographs are well established in the diagnosis of fractures, they are more expensive, may introduce radiation (CT and X-ray), and are not readily available on the sideline or in all training rooms. Furthermore, ultrasound has been shown superior to radiographs for detection of certain fractures, such as those of the ribs and sternum and for detection of radiographically occult fractures of the wrist (^56–59). Sports US may be a safe and effective way to rapidly evaluate for fractures in appropriate clinical environments.

Fracture US Technique

Transducer: high frequency linear-array transducer

Patient position: position of comfort with affected limb at rest

Transducer position: over point of maximal bony tenderness

Key Views:

•  - Affected bone should be visualized in long and short axes

Key Findings:

•  - Cortical disruption/discontinuity
•  - Soft tissue edema
•  - Perifracture hematoma
•  - Localized hyperemia on Doppler
•  - Joint effusion

(See Fig. 7 here https://links.lww.com/CSMR/A90)

As summarized in Table 8 above, data varies on use of US in fracture evaluation, depending on the body part and population. While sports US will not replace radiographs in the evaluation of fracture, it is a viable alternative when X-ray is not readily available or contraindicated.

Table 8 - Accuracy of US for evaluation and diagnosis of traumatic fractures.

Year	Author	Population	Fracture Site	Sens (%)	Spec (%)	PPV (%)	NPV (%)	Accuracy (%)
2019	Epema et al. (60)	Pediatric	Forearm	95	86	92	91	92
2019	Kozaci et al. (21)	Adult	Sternal	83	97
			Clavicular	83	100
			Rib	67	98
2019	Masaeli et al. (61)	Pediatric	Skull	92	96
2019	Ko et al. (62)	Pediatric	Forearm	97	100	100	94
2018	Parri et al. (63)	Pediatric	Skull	91	85
2017	Døssing et al. (64)	Adult	Extremity	92	94	85	97
2017	Hedelin et al. (65)	Pediatric	Wrist	97	84
2017	Pishbin et al. (57)	Adult and Pediatric	Rib	98	100	100	96
2017	Rowlands et al. (66)	Pediatric	Forearm	92	88
2016	Aksay et al. (67)	Adult and pediatric	Finger	79	90	72	93
2015	Dallaudière et al. (68)	Adult	Variable	98	98	100	95	99
2015	Herren et al. (56)	Pediatric	Forearm	100	100
2015	Kozaci et al. (69)	Adult and Pediatric	Forearm	98	96	98	96	98
2014	Atilla et al. (70)	Adult	Foot and Ankle	87	96
2013	Eckert et al. (71)	Pediatric	Elbow	98	95	98	95
2013	Waterbrook et al. (72)	Adult and Pediatric	Variable	90	96	90	96
2013	Bolandparvaz et al. (73)	Adult	Upper and lower limb	55–75	62–84	33–71	73–83
2013	Ekinci et al. (74)	Pediatric	Foot and Ankle	100	99	95	100
2013	Parri et al. (75)	Pediatric	Skull	100	95	97	100
2013	Rabiner et al. (76)	Pediatric	Elbow	98	70
2012	Barata et al. (77)	Pediatric	Long bone	95	86	84	96
2012	Beltrame et al. (78)	Adult and Pediatric	Variable, no intraarticular	94	92	94	91	93
2011	Chaar-Alvarez et al. (79)	Pediatric	Forearm	96	93	92	96	94
2011	Chien et al. (80)	Pediatric	Clavicle	90	90	95	81
2011	Sinha et al. (81)	Pediatric	Limb injuries	89	100	100	97
2010	Ackermann et al. (82)	Pediatric	Forearm	94	99
2010	Weinberg et al. (83)	Pediatric	Variable	73	92
2010	You et al. (58)	Adult	Sternal	100	100

Boxes left blank were not reported in the study.

Conclusions

The role of sports US in the assessment of acute traumatic injury is still being defined. Despite this, we encourage all sports medicine physicians to become comfortable and competent with basic ultrasound diagnostic techniques for acute conditions. As outlined above, there are multiple techniques for rapidly assessing a patients’ clinical status including but not limited to respiratory, cardiac, orthopedic, and hemodynamic evaluation. The literature supports these techniques as effective for first-line evaluation of these injuries. The RUSH and FAST ultrasound protocols provide rapid and comprehensive assessment for traumatic and acute injuries in more concerning patients which may assist sports medicine physicians in determining disposition and urgency of transport for athletes injured on the field of play. Regardless of primary specialty, sports medicine physicians should consider adding these additional sports US examinations for immediate evaluation of an athlete to their repertoire.

In part 2 of this review, we will discuss additional uses of ultrasound for evaluation of acute conditions in athletes, including evaluation for acute ocular injury, elevated intracranial pressures, cellulitis, deep venous thrombosis, and lymphadenopathy.