TRAIN CERTIFY MAINTAIN
Family Medicine Musculoskeletal (FM MSK)
CURRICULUM
Advanced skills for certification
a. Probe
Linear probe.
b. Knobology
i. Preset. MSK or small parts.
ii. Depth. Start at depth of 5 cm. Adjust as needed.
iii. Gain. Default. Adjust as needed.
c. Patient positioning.
d. Probe orientation
e. Probe grip
Pencil grip.
a. External landmark
b. Internal landmark
Cortex of sternum.
c. Relevant anatomy
d. Area of interest
e. Adequate view
a. Image generation
i. Landmark.
- Start the scan at the suprasternal (jugular) notch.
- Finish the scan at the xiphoid process.
ii. Optimize image
- Decrease depth once you have identified sternal cortex.
- Increase probe frequency to increase image resolution.
iii. Technique
- Start scan on the external landmark in the midline in LAX.
- Slide probe side to side to centre sternum cortex on screen.
- Sweep and rock probe to image a well-defined sternal cortex.
- Slide caudally keeping cortex well-defined and centred.
- End scan when xiphoid process reached.
- Rotate probe 90 degrees in SAX and repeat scan.
iv. Interrogate AOI
- The AOI is the cortical line of the sternum.
- Scan in LAX:
- Look for a discontinuity/step off of the cortex line.
- Look for hematoma above fracture site.
- Scan in SAX:
- Look for cortex line to jump to near field (anterior) or far field (posterior) indicating a discontinuity of the bone (aka a fracture!) where the jump occurs.
b. Image interpretation
The following areas should be evaluated and a binary yes/no conclusion made:
i. Sternal fracture? (YES/NO).
a. Rotate probe in short axis to confirm centre of sternum under probe.
a. Technique
i. POCUS only gives information about the interrogated bone surfaces. If the anterior bone surface is evaluated only antero-posterior abnormalities (step off, angulation, displacement) can be appreciated.
ii. It is easier than we think to stray away from sternum midline. Steady your hand and take care to keep your AOI centred at all times.
b. Image interpretation
i. False positives (mistaking these normal findings for fracture sites):
- Sternal angle (manubriosternal angle).
- Xiphisternum (junction of sternal body with xiphoid process).
- Incomplete fusion and growth plates (children).
- Failure of midline fusion.
- Sternoclavicular or sternocostal joint spaces.
ii. Remember that normal growth plates have:
- A well-defined cortex line compared to jagged edges of fracture sites.
- No hematoma above them.
iii. Remember that joint spaces will have:
- A classic U or V-shape appearance (sharp ‘drop’ of cortical ends on both sides of space).
- Non-displaced smooth cortical edges.
- When in doubt, compare to unaffected side (for sternoclavicular joints and sternocostal joints).
iv. Sternal angle and xiphisternum are flat bone junctions that will have smooth contours and will not be displaced.
v. Ridge and incomplete fusion are at the junction of the sternum with the costal cartilage.
c. Clinical integration
i. High grade fracture is present when both sides of the fracture fragments are moving independently.
ii. Highly displaced fractures may warrant further investigation of underlying structures. Further imaging and assessment are needed.
iii. If clinical suspicion remains high and POCUS exam is negative, further imaging studies are recommended.
a. Fractures are usually found at the site of maximal tenderness-ask the collaborating patient to point you in the right direction.
b. No need to put pressure on the probe-add lots of gel and ‘float the probe’ to avoid causing added pain to your patient.
a. For a negative scan:
i. Must image a well-defined centred sternal cortex from the jugular notch to the xiphoid process in 2 planes.
ii. No fracture is identified.
b. For a positive scan:
i. Must image a well-defined centred sternal cortex from the jugular notch to the xiphoid process in 2 planes.
ii. A fracture is identified.
Document as per CPoCUS guidelines for positives and negatives according to clinical indications:
a. Sternal fracture + or –
b. Indeterminate
Prerequisites
Appropriate didactic and practical introduction to technique that must include written materials covering all relevant ultrasound physics, anatomy and theory, a minimum of 30 minutes of live or on-line lectures, and at least 5 introductory proctored sternum scans.
The introductory scans do not count towards certification and do not need to be determinate.
Logged scan requirements
- 3 sternum determinate scans supervised directly by a CPoCUS MSK Track Instructor for the entirety of the scan.
- Determinate scans are defined in ‘Determinate scan requirements’.
- A minimum of x scans (to be determined) must be done ‘unassisted’.
- An unassisted scan is one in which the learner generates a determinate image and uses appropriate troubleshooting maneuvers without any assistance (verbal or physical) from the instructor.
- There is no requirement for a minimum number of positive scans.
- All scans must be recorded in a CPoCUS logbook.
Examinations
Pass mark on CPoCUS sternum written, practical, and visual examinations PLUS appropriate prerequisites AND logged scans as above.
Note: Prerequisites and/or logged scan requirements may be waived if a candidate is awarded a CPoCUS Exception to Certification (see website for application details).
a. Probe
Linear probe.
b. Knobology
i. Preset. MSK or small parts.
ii. Depth. Start at depth of 5 cm. Adjust as needed.
iii. Gain. Default. Adjust as needed.
c. Patient positioning.
d. Probe orientation
Rib’s short axis (SAX) with probe indicator oriented toward the ceiling and rib’s long axis (LAX) with probe indicator oriented toward operator’s left.
e. Probe grip
Pencil grip.
a. External landmark
b. Internal landmark
Anterior cortex of the rib.
c. Relevant anatomy
d. Area of interest
e. Adequate view
a. Image generation
i. Landmark.
- Start scan at area of maximal tenderness in rib’s SAX.
- Finish after having scanned one probe length anteriorly and posteriorly to the point of maximal tenderness in rib’s SAX and LAX and one rib above and one rib below area of maximal tenderness.
ii. Optimize image
- Once rib is identified, decrease depth to center it on screen.
- Adjust gain as needed and increase probe frequency to increase image resolution.
iii. Technique
- Start scan at area of maximal tenderness in rib’s SAX.
- Center affected rib on screen by sliding cephalad to caudad on the rib’s SAX.
- Sweep probe side to side to obtain a well-defined (thin, bright white) rib cortex image.
- Slide anterior-posterior-anterior to scrutinize area of maximal tenderness.
- Extend scan one probe length beyond borders of area of maximal tenderness (anteriorly and posteriorly).
- Rotate probe in rib’s LAX in area of maximal tenderness.
- Sweep probe cephalad to caudad to obtain a well-defined (thin, bright white) rib cortex image.
- Keep rib cortex centered while sliding anterior-posterior-anterior to scrutinize area of maximal tenderness by using index and middle finger of non-scanning hand to track intercostal spaces on each side of the interrogated rib.
- Extend scan one probe length beyond borders of area of maximal tenderness (anteriorly and posteriorly).
- Rotate back in rib’s SAX.
- Slide cephalad in rib’s SAX and repeat above steps for rib above area of maximal tenderness.
- Slide caudally in rib’s SAX and repeat above steps for rib below area of maximal tenderness.
iv. Interrogate AOI
- The AOI is the cortical line of the rib.
- Scan in rib’s SAX:
- Look for a step off in the cortical line.
- Look for hematoma.
- Scan in rib’s LAX:
- Look for a discontinuity/step off or angulation of the cortical line.
- Look for hematoma (anechoic collection near field to cortex.
b. Image interpretation
The following areas should be evaluated and a binary yes/no conclusion made:
i. Rib fracture? (YES/NO).
a. Decrease depth and increase probe frequency if needed.
b. Adjust gain as needed.
c. Use your index and middle finger to track intercostal spaces on each side of the interrogated rib to help maintain the rib centered in LAX.
a. Technique
i. Be careful and proceed slowly when following the rib as it can easily be lost on screen due to its rounded shape and similarly shaped surrounding structures.
ii. Some patients might not be able to tolerate the scan if appropriate analgesia is not provided.
iii. Apply copious amounts of gel to minimize pressure over tender areas and float the probe.
b. Image interpretation
i. Be sure to differentiate between rib and pleura:
- The rib has an acoustic shadow far field.
- Pleura moves as the patient breathes. It has a shimmering hyperechoic line with dispersion far field.
ii. False positives:
- Costovertebral junction: the rib drops sharply far field near the spine. Look at your external landmarks!
- Costochondral junction: with probe on cartilage, it is usually possible to see pleura far field while rib shadow won’t usually allow anything to be seen far field to the bone.
c. Clinical integration
i.Many rib fractures with minimal displacement are missed on x-rays and POCUS can pick up the slack. Patients need to be able to locate point of maximal tenderness for it to be worth your time. This is not a full ribcage scan!
ii. Unconscious polytrauma patients rib fractures will be easily picked up by the standard trauma CT pan-scan. Don’t waste your valuable time.
iii. Ambulatory patients with suspected rib fracture(s) after relatively minor trauma with no indication for exhaustive investigation are your population target for this scan.
iv. Ultrasound cannot detect posterior rib fractures under the scapula.
v. A complete evaluation of the rib from posterior (costovertebral junction) to anterior (costochondral junction) is rarely necessary: it could maybe be useful if doubt in a patient with a more difficult history. Set an amount of time you want to spend looking at ribs in these patients.
vi. Evaluation of pleura and upper quadrants is warranted if suspicion of pneumothorax, hemothorax or hemoperitoneum.
vii. Flail chests are going to take a long time to assess with POCUS! Using other imaging modalities in this type of clinical presentation is recommended.
a. Scrutinize the area of maximal tenderness thoroughly.
b. Scrutinize rib above and below area of maximal tenderness. Fractures tend to occur from direct impact on chest. There might be more than one fracture to be found in the area of maximal tenderness!
c. Always try to confirm fracture in rib’s SAX and LAX.
d. The rib’s SAX is useful to differentiate bone cortex (white curvy line) from soft tissue and pleura.
e. It is more difficult to identify a fracture in SAX than in LAX.
f. The overlying hematoma might be your first visual clue that there is a rib fracture to be found. Scrutinize the area meticulously.
a. For a negative scan:
i. Must image the affected rib in long and short axis from several cm posterior to several cm anterior to the point of maximal tenderness in LAX and SAX.
ii. No fracture is identified.
b. For a positive scan:
i. Must image the affected rib in long and short axis from several cm posterior to several cm anterior to the point of maximal tenderness in LAX and SAX.
ii. A fracture is identified.
Document as per CPoCUS guidelines for positives and negatives according to clinical indications:
a. Rib fracture + or –
b. Indeterminate
Prerequisites
Appropriate didactic and practical introduction to technique that must include written materials covering all relevant ultrasound physics, anatomy and theory, a minimum of 30 minutes of live or on-line lectures, and at least 5 introductory proctored rib scans.
The introductory scans do not count towards certification and do not need to be determinate.
Logged scan requirements
- 3-5 rib determinate scans supervised directly by a CPoCUS MSK Track Instructor for the entirety of the scan.
- Determinate scans are defined in ‘Determinate scan requirements’.
- A minimum of x scans (to be determined) must be done ‘unassisted’.
- An unassisted scan is one in which the learner generates a determinate image and uses appropriate troubleshooting maneuvers without any assistance (verbal or physical) from the instructor.
- There is no requirement for a minimum number of positive scans.
- All scans must be recorded in a CPoCUS logbook.
Examinations
Pass mark on CPoCUS rib written, practical, and visual examinations PLUS appropriate prerequisites AND logged scans as above.
Note: Prerequisites and/or logged scan requirements may be waived if a candidate is awarded a CPoCUS Exception to Certification (see website for application details).
a. Probe
b. Knobology
i. Preset. MSK or small parts.
ii. Start at 5-8 cm with linear probe depending on patient’s musculature and body habitus. Start at around 10 cm with curvilinear probe. Adjust as needed.
iii. Gain. Default. Adjust as needed.
c. Patient positioning.
d. Probe orientation
e. Probe grip
Pencil grip.
a. External landmark
b. Internal landmark
c. Relevant anatomy
d. Area of interest
LAX anterior and lateral scan of humeral cortex.
e. Adequate view
a. Image generation
i. Landmark.
- Start scan on the anterior humerus at the level of the external landmark.
- Finish the scan at the elbow crease.
ii. Optimize image
- Once humeral cortex is identified, modify depth to centre it on screen.
- Adjust gain and probe frequency in accordance with patient’s body habitus.
iii. Technique
- LAX anterior:
- Start scan on anterior shoulder in LAX anterior.
- Centre humerus by sliding side to side.
- Sweep probe to image a well-defined (thin, bright white) humeral cortex.
- Slide probe distally while keeping humeral cortex centred and well-defined.
- Stop when elbow crease reached.
- LAX lateral:
- Start scan on lateral shoulder in LAX lateral.
- Centre humerus by sliding side to side.
- Sweep probe to image a well-defined (thin, bright white) humeral cortex.
- Slide probe distally while keeping humeral cortex centred and well-defined.
- Stop when elbow joint reached.
- To increase sensitivity, humerus can also be scanned in SAX in those 2 planes.
iv. Interrogate AOI
- The AOI is the cortical line of the humerus.
- Scan in LAX anterior and LAX lateral:
- Look for a discontinuity/step off or angulation of the cortical line.
- Look for hematoma (anechoic collection near field to cortex).
- Scan in SAX:
- Look for a step off in the cortical line.
- Look for hematoma.
b. Image interpretation
The following areas should be evaluated and a binary yes/no conclusion made:
i. Humeral shaft fracture? (YES/NO).
a. Rotate probe in transverse to find humeral cortex.
b. Modify depth and probe frequency as needed.
a. Technique
i. Failure to image in both LAX anterior and lateral can miss fractures. Think about X-rays and their standard 2 views of most things: AP and lateral. We are aiming for the same principle here. In addition, you can also confirm fractures in SAX in the same two planes.
ii. Patient might be unable to tolerate positioning for assessment without analgesia. Use copious amounts of gel to minimize pressure on tender areas and float the probe!
iii. Humeral width is not as large as expected. This makes it easy to lose the cortex on the screen if probe moves only a few millimeters out of plane. You can use your non-scanning hand to stabilize your scanning hand on patient.
b. Image interpretation
i. Ultrasound only gives information about the interrogated bone surfaces. If the anterior bone surface is evaluated only antero-posterior abnormalities (step off, angulation, displacement) can be appreciated. Complete exam with as many planes as you deem necessary to have a good idea of bone integrity.
ii. Pediatric patients can present with different fracture patterns than adults. Fractures in children can present with:
- Cortical gap.
- Cortical bulging.
- Cortical deviation.
- Hematoma covering bone cortex in all views.
iii. Growth plates can be mistaken for fractures if not careful. Immobilize and refer as per local practice when suspecting a growth plate fracture or use other imaging modalities. Remember that normal growth plates have:
- A well-defined cortex line compared to jagged edges of fracture sites.
- No hematoma above them.
- Symmetry with unaffected side.
c. Clinical integration
i. Unconscious polytrauma patients can’t tell you where it hurts and CT pan-scans won’t pick-up most humeral shaft fractures. Think about using this scan as a screening test for long bone fractures of the upper extremity in the trauma bay.
ii. Greenstick, torus (buckle) and growth plate fractures are harder to identify on ultrasound. Look for near field hematomas, scrutinize point of maximal tenderness or… get X-ray!
iii. Open fractures should not be scanned with ultrasound.
iv. If clinical suspicion remains high and POCUS exam is negative, further imaging studies are recommended.
a. Pay attention to the site of maximal tenderness. If patient is able to tell you where it hurts, start there as it will save you tons of time!
b. Transverse plane is very useful to differentiate bone cortex (curvy) from soft tissue.
a. For a negative scan:
i. Must image the well-defined bony cortex of humerus shaft from external landmark to elbow crease in both LAX anterior and LAX lateral.
ii. No fracture is identified.
b. For a positive scan:
i. Must image the well-defined bony cortex of humerus shaft from external landmark to elbow crease in both LAX anterior and LAX lateral.
ii. A fracture is identified.
Document as per CPoCUS guidelines for positives and negatives according to clinical indications:
a. Humeral shaft fracture + or –
b. Indeterminate
Prerequisites
Appropriate didactic and practical introduction to technique that must include written materials covering all relevant ultrasound physics, anatomy and theory, a minimum of 30 minutes of live or on-line lectures, and at least 5 introductory proctored humeral shaft scans.
The introductory scans do not count towards certification and do not need to be determinate.
Logged scan requirements
- 3 humeral shaft determinate scans supervised directly by a CPoCUS MSK Track Instructor for the entirety of the scan.
- Determinate scans are defined in ‘Determinate scan requirements’.
- A minimum of x scans (to be determined) must be done ‘unassisted’.
- An unassisted scan is one in which the learner generates a determinate image and uses appropriate troubleshooting maneuvers without any assistance (verbal or physical) from the instructor.
- There is no requirement for a minimum number of positive scans.
- All scans must be recorded in a CPoCUS logbook.
Examinations
Pass mark on CPoCUS humeral shaft written, practical, and visual examinations PLUS appropriate prerequisites AND logged scans as above.
Note: Prerequisites and/or logged scan requirements may be waived if a candidate is awarded a CPoCUS Exception to Certification (see website for application details).
a. Probe
Linear probe or high frequency probe of choice (10 MHz or more).
b. Knobology
i. Preset. MSK or small parts.
ii. Depth. Start at 5 cm. Adjust as needed.
iii. Gain. Initially set at mid-range. Adjust as needed.
c. Patient positioning
d. Probe orientation
e. Probe grip
a. External landmark
b. Internal landmark
c. Relevant anatomy
d. Area of interest
e. Adequate view
i. Dorsal plane: hyperechoic and well-defined (thin and bright white) cortex of DR and RCJ.
ii. Radial plane: hyperechoic and well-defined cortex of DR.
a. Image generation
i. Landmark
- Start scan in LAX dorsal plane in the midline on DR.
- End scan when RCJ is visualized.
- Re-position probe on LAX radial plane of DR.
- End-scan when DR has been imaged distal to proximal.
ii. Optimize image
- Adjust depth to centre image.
- Increase probe frequency to increase image resolution.
- Increase gain to better see white bone cortices.
- Decrease gain to visualize effusions.
iii. Technique
- LAX DORSAL. Start scan in LAX dorsal plane on DR.
- Centre the probe midline on dorsal radius by sliding side to side.
- Sweep probe to obtain hyperechoic and well-defined image of DR cortex.
- Slide distally keeping radius cortex well-defined until RCJ is identified.
- Slide probe radial to ulnar keeping RCJ centred to assess the whole joint space looking for effusion.
- LAX RADIAL. Slide probe radially to visualize RCJ in LAX radial plane.
- Slide proximally to image DR shaft.
- Sweep probe or slide side to side to keep radius cortex well-defined and centred.
- Slide distally to visualize RCJ.
iv. Interrogate AOI
- Scan DR shaft in LAX dorsal and LAX radial planes.
- Identify RCJ.
- Slide radial to ulnar to assess the whole joint in LAX dorsal plane.
b. Image interpretation
The following areas should be evaluated and a binary yes/no conclusion made:
i. DR fracture? (YES/NO).
ii. RCJ fracture? (YES/NO).
a. Rotate probe in short axis to confirm DR cortex line.
b. Decrease depth and increase probe frequency as needed.
a. Technique
i. Failure to image in both LAX dorsal and radial planes can miss fractures. Think about X-rays and their standard 2 views of most things: AP and lateral. We are aiming for the same principle here. In addition, you can also confirm fractures in SAX in the same two planes.
ii. Patient might be unable to tolerate positioning for assessment without analgesia. Use copious amounts of gel to minimize pressure on tender areas and float the probe!
iii. Radius width is not as large as expected making it is easy to lose cortex on screen if probe moves only a few millimeters off in the LAX plane. You can use your non-scanning hand to stabilize your scanning hand on patient.
iv. The RCJ extends from the radial to the ulnar side of the wrist: slide medial (radial) to lateral (cubital) to avoid missing small effusions.
b. Image interpretation
i. Ultrasound only gives information about the interrogated bone surfaces. Complete exam with as many planes as you deem necessary to have a good idea of bone integrity.
ii. Pediatric patients can present with different fracture patterns than adults.
- Fractures in children can present with:
- Cortical gap.
- Cortical bulging.
- Cortical deviation.
- Hematoma covering cortex in all views.
- Remember that normal growth plates have:
-A well-defined cortex line compared to jagged edges of fracture sites.
-No hematoma above them.
-Symmetry with unaffected side! - Immobilize and refer as per local practice when suspecting a growth plate fracture or use other imaging modality.
vi. Ultrasound cannot reliably differentiate between a septic and an aseptic effusion. High clinical suspicion and correlation are warranted and arthrocentesis is recommended to help refine diagnosis and treatment if clinician is worried about a septic joint.
vii. NERD ALERT!! LISTER’S TUBERCLE. A tubercle is a normal bony prominence at the end of a bone, a ‘bone bump’ of sorts. Lister’s tubercle is palpable on the dorsal wrist on the DR. Just palpate yours right now! Don’t make the mistake of calling it a fracture. Its smooth cortical line in continuity with the DR and absence of hematoma should help you recognizing it for what it is: normal anatomy. If in doubt, remember that you can always compare with unaffected side! Lister’s tubercle also serves as a pulley for the extensor pollicis longus and is used as an anatomy landmark in wrist arthroscopy and injections.
c. Clinical integration
i. Look for effusion in trauma or in painful, red, and swollen joints.
ii. Septic arthritis is a surgical emergency. Finding an effusion in a patient with a high suspicion of septic joint warrants urgent surgical consultation.
iii. Clinical correlation needed! If high suspicion remains, use other modalities to further assess for DR fracture.
a. The RCJ is best visualized with wrist in slight flexion. Use of a rolled towel or similar is recommended.
b. DR scan can help with assessment of displaced Colles’ fractures reductions:
i. Note gap between distal and proximal ends of fracture on LAX radial view.
ii. Hematoma block can also be performed following first scan before reduction attempt.
iii. Proceed with reduction attempt.
iv. Assess for adequate reduction by rescanning patient in same LAX radial view.
v. If reduction deemed inadequate, proceed to re-attempt reduction without analgesia wearing off or waiting for confirmatory X-rays!
c. PROCEDURAL POCUS: US-guided RCJ arthrocentesis:
i. Patient can be seated or supine with forearm supported on examination table and wrist in slight flexion (resting on a rolled towel or similar.
ii. Operator is facing the patient.
iii. Probe is placed on dorsal aspect of DR in LAX.
iv. In-plane needle visualization is recommended and needle entry is planned distal to proximal.
v. Use of a probe with a smaller footprint like a hockey stick probe is recommended if available.
vi. If space for needling without hitting the bone is too limited with probe in contact with RCJ, tilt probe 30 degrees cephalad creating a gap at the caudal end.
vii. Fill that gap with sterile gel and float the probe making space for needle entry.
viii. Needle should be visualized at all times.
a. For a negative scan:
i. Must image well-defined DR in LAX dorsal and LAX radial planes.
ii. Must image RCJ in LAX dorsal plane.
iii. Entire RCJ must be scrutinized by sliding probe from radial side to ulnar side of wrist.
iv. No fractures or effusions seen.
b. For a positive scan:
i. Must image well-defined DR in LAX dorsal and radial planes.
ii. Must image RCJ in LAX dorsal plane.
iii. Entire RCJ must be scrutinized by sliding probe from radial side to ulnar side of wrist.
iv. A DR fracture is identified and\or
iv. A RCJ effusion is identified.
Document as per CPoCUS guidelines for positives and negatives according to clinical indications:
a. DR fracture + or –
b. RCJ effusion + or –
c. Indeterminate
Prerequisites
Appropriate didactic and practical introduction to technique that must include written materials covering all relevant ultrasound physics, anatomy and theory, a minimum of 30 minutes of live or on-line lectures, and at least 5 introductory proctored DR/RCJ scans.
The introductory scans do not count towards certification and do not need to be determinate.
Logged scan requirements
- 5 wrist DR/RCJ determinate scans supervised directly by a CPoCUS MSK Track Instructor for the entirety of the scan.
- Determinate scans are defined in ‘Determinate scan requirements’.
- A minimum of x scans (to be determined) must be done ‘unassisted’.
- An unassisted scan is one in which the learner generates a determinate image and uses appropriate troubleshooting maneuvers without any assistance (verbal or physical) from the instructor.
- There is no requirement for a minimum number of positive scans.
- All scans must be recorded in a CPoCUS logbook.
Examinations
Pass mark on CPoCUS DR/RCJ written, practical, and visual examinations PLUS appropriate prerequisites AND logged scans as above.
Note: Prerequisites and/or logged scan requirements may be waived if a candidate is awarded a CPoCUS Exception to Certification (see website for application details).
a. Probe
b. Knobology
i. Preset. MSK.
ii. Start at depth of 15 cm in most patients. Start at 8-10 cm in most pediatric patients. Adjust as needed.
iii. Gain. Default. Adjust as needed.
c. Patient positioning.
d. Probe orientation
LAX anterior, and either LAX medial or LAX lateral (all with probe indicator towards patient’s head). Can also confirm in SAX anterior (probe indicator towards patient’s right).
e. Probe grip
Pencil grip.
a. External landmark
b. Internal landmark
c. Relevant anatomy
d. Area of interest
e. Adequate view
a. Image generation
i. Landmark.
- Start the scan on the anterior femur at the external landmark.
- Finish the scan at the patella.
ii. Optimize image
- Once femur is identified, modify depth to centre it on screen.
- Adjust gain and probe frequency in accordance with patient’s body habitus.
iii. Technique
- LAX anterior:
- Start scan on external landmark close to greater trochanter.
- Slide probe side to side to centre femoral cortex on screen.
- Sweep probe to image a well-defined (thin, bright white) femoral cortex.
- Slide caudally while keeping femur well-defined and centred.
- End scan when patella is imaged on screen.
- LAX medial (or lateral):
- Start scan on external landmark for LAX anterior and slide 90 degrees medially (or laterally).
- Slide probe side to side to centre femoral cortex on screen.
- Sweep probe to image a well-defined (thin, bright white) femoral cortex.
- Slide caudally while keeping femur well-defined and centred.
- End scan when knee joint is seen on screen.
- If impossible to scan in LAX medial or LAX lateral, rotate probe in SAX anterior and repeat steps as for LAX anterior.
iv. Interrogate AOI
- The AOI is the cortical line of the femur.
- Scan in LAX anterior and LAX medial (or lateral):
- Look for a discontinuity/step off or angulation of the cortical line.
- Look for hematoma (anechoic collection near field to cortex).
- If SAX anterior only other view option:
- Look for a step off in the cortical line.
- Look for hematoma.
b. Image interpretation
The following areas should be evaluated and a binary yes/no conclusion made:
i. Femoral shaft fracture? (YES/NO).
a. Remember that most femoral shaft fracture patients will present with affected hip and thigh in some degree of external rotation and abduction making LAX lateral difficult or impossible to obtain.
b. You might also not be able to obtain a good LAX medial view due to pain and position issues.
c. Rotate probe in transverse to identify femoral cortex.
d. Modify depth and probe frequency as needed.
a. Technique
i. Failure to image in both LAX anterior and medial (or lateral) can miss fractures. Think about X-rays and their standard 2 views of most things: AP and lateral (or medial). We are aiming for the same principle here. In addition, you can also confirm fractures in SAX in the same planes.
ii. Patient might be unable to tolerate positioning for assessment without analgesia. Use copious amounts of gel to minimize pressure on tender areas and float the probe!
b. Image interpretation
i. Imaging bone in only one plane can miss fractures. Ultrasound only gives information about the interrogated bone surface: if the anterior bone surface is evaluated, only anteroposterior abnormalities (step off, angulation, displacement) can be appreciated. Always think about looking on the lateral (or medial) side of the femur in coronal (long axis) and transverse (short axis) planes to complete evaluation.
ii. Femur width might not be as large as expected. It is easy to lose sight of the cortex if probe only moves a few millimeters lateral or medial in the sagittal plan.
c. Clinical integration
i. Most patients with femoral shaft fractures will present with a clear clinical exam and telltale thigh deformity. Put your probe down and give them analgesia! Attempt reduction and traction as needed as per local protocols.
ii. Unconscious polytrauma patients can’t tell you where it hurts and CT pan-scans won’t pick-up most femoral shaft fractures. Think about using this scan as a screening test for long bone fractures of the lower extremity in the trauma bay.
iii. Pediatric patients can present with fracture patterns different than adults. Greenstick, torus (buckle) and growth plate fractures are harder to identify on ultrasound. Look for near field hematomas, scrutinize point of maximal tenderness or… get X-ray!
iv. Open fractures should not be scanned with ultrasound.
v. Clinical correlation needed! If high suspicion remains, use other modalities to further assess for femoral shaft fracture.
a. Pay attention to the site of maximal tenderness. If patient is able to tell you where it hurts, start there as it will save you tons of time!
b. Transverse plane is very useful to differentiate bone cortex (curvy) from soft tissue.
a. For a negative scan:
i. Must image the well-defined femoral cortex from the proximal external landmark to the patella (or knee joint) in 2 planes.
ii. No fracture is identified.
b. For a positive scan:
i. Must image the well-defined femoral cortex from the proximal external landmark to the patella (or knee joint) in 2 planes.
ii. A fracture is identified.
Document as per CPoCUS guidelines for positives and negatives according to clinical indications:
a. Femoral shaft fracture + or –
b. Indeterminate
Prerequisites
Appropriate didactic and practical introduction to technique that must include written materials covering all relevant ultrasound physics, anatomy and theory, a minimum of 30 minutes of live or on-line lectures, and at least 5 introductory proctored femoral shaft scans.
The introductory scans do not count towards certification and do not need to be determinate.
Logged scan requirements
- 3 femoral shaft determinate scans supervised directly by a CPoCUS MSK Track Instructor for the entirety of the scan.
- Determinate scans are defined in ‘Determinate scan requirements’.
- A minimum of x scans (to be determined) must be done ‘unassisted’.
- An unassisted scan is one in which the learner generates a determinate image and uses appropriate troubleshooting maneuvers without any assistance (verbal or physical) from the instructor.
- There is no requirement for a minimum number of positive scans.
- All scans must be recorded in a CPoCUS logbook.
Examinations
Pass mark on CPoCUS femoral shaft written, practical, and visual examinations PLUS appropriate prerequisites AND logged scans as above.
Note: Prerequisites and/or logged scan requirements may be waived if a candidate is awarded a CPoCUS Exception to Certification (see website for application details).