TRAIN CERTIFY MAINTAIN
Family Medicine Musculoskeletal (FM MSK)
CURRICULUM
Advanced skills for certification
a. Probe
b. Knobology
i. Preset. MSK or small parts.
ii. Depth. Start at around 15 cm in larger adults with curvilinear probe. Start at 8-10 cm with linear probe. 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
a. Image generation
i. Landmark
- Start the scan just below the scapular line at the medial aspect of the humeral head.
- Find the GHJ—area of articulation between humeral head and glenoid (bony cortices must appear well-defined aka thin and bright white).
- End the scan after sweeping through GHJ in transverse.
ii. Optimize image
Adjust depth to centre image.
Increase probe frequency to increase image resolution.
iii. Technique
Remember that this is a POSTERIOR scan.
Start the scan with probe in transverse just below the scapular line at the medial aspect of the humeral head.
- Find the hyperechoic rounded bony cortex of the humeral head by sliding lateral to medial.
- Sweep or slide cephalad to caudad to visualize a well-defined rounded humeral cortex (thin and bright white).
- Try to keep probe steady and parallel to infraspinatus muscle fibers by slightly rotating probe if needed.
- Slide probe cephalad (or caudad) until V-shaped joint space visible.
- Make sure to appreciate relationship between glenoid and medial aspect of humeral head in the same plane when no dislocation present.
- Sweep cephalad to caudad to ensure bony cortices are well-defined.
- Center GHJ by sliding side to side if needed.
- Sweep GHJ looking for an effusion.
iv. Interrogate AOI
Sweep probe cephalad to caudad when evaluating for a GHJ effusion.
Small amount of fluid may only be visible with the shoulder in external rotation.
a. Use dynamic active or passive testing by gently making patient rotate their arm externally (if possible).- Assess for continuity between glenoid and humeral head:
a. Humeral head seen near field to glenoid represents a POSTERIOR shoulder dislocation.
b. Humeral head seen far field to glenoid represents an ANTERIOR shoulder dislocation.
b. Image interpretation
The following areas should be evaluated, and a binary yes/no conclusion made:
i. GHJ effusion? (YES/NO).
ii. GHJ dislocation? (YES/NO). If yes, specify if dislocation is anterior or posterior
a. Use curved array probe in larger patients and linear probe in smaller or pediatric patients.
b. Increase depth when using linear probe in larger patients.
c. Decrease depth and increase probe frequency when using the curvilinear probe to increase image resolution.
a. Technique
i. Starting scan too lateral or too cephalad or caudad can result in a waste of time: remember your external landmarks!
b. Image interpretation
i. Small amount of fluid may only be visible with shoulder in external rotation: use dynamic testing to make sure not to miss anything!
c. Clinical integration
i. Remember that fluid in the GHJ can be present in a large array of clinical presentations. Clinical suspicion is paramount to help differentiate between traumatic effusions, OA effusions, septic joint, etc. When high clinical suspicion for a septic GHJ is present, tapping joint under real-time US-guidance can help confirm diagnosis.
ii. When shoulder dislocation is seen on POCUS, GHJ can be injected with local anesthetics under US-guidance to provide analgesia prior to reduction attempt.
iii. NERD ALERT! US-guided aspirations and injections of the GHJ are a great way to refine your differential, relieve patients’ acute pain (hemarthrosis aspiration prior to GHJ block) and chronic pain GHJ OA (cortisone injection) and it’s a big ‘target’ for your needle. If possible, using a linear probe will make visualization of the needle trajectory easier and more intuitive for the beginner MSK-POCUS provider.
iv. Remember to call your orthopedic surgeon before attempting an arthrocentesis in patients with a prosthetic shoulder.
a. Scanning pre and post reduction
i. You can assess for shoulder reduction before analgesia wears off by rescanning the GHJ and seeing the humeral head’s relationship with the glenoid restored.
ii. If still dislocated, you can reattempt reduction while patient still sedated and reassess with POCUS after other attempts until reduction successful.
iii. Dynamic testing by gently rotating shoulder externally while adducted can facilitate GHJ integrity assessment. When in doubt compare with unaffected side.
b. Procedural POCUS: GHJ US guided arthrocentesis
i. Put patient in a lateral recumbent position with affected side up.
ii. Transducer will be in a transverse oblique plane (parallel to fibers of infraspinatus tendons).
iii. Needle approach will be lateral to medial in an ‘in-plane’ orientation to visualize needle trajectory.
iv. Target of needle will be the posterior GHJ between humeral head and glenoid labrum.
c. NERD ALERT!
i. If injecting local anesthetics or cortisone, always aspirate before injecting and see fluid spread in the GHJ posterior fossa as you inject.
a. For a negative scan:
i. Must image GHJ with the glenoid and humeral head relationship visualized in the same plane if no dislocation present.
ii. Must sweep GHJ looking for effusion.
iii. Must externally rotate shoulder of patient to assess for smaller effusion (if patient’s condition allows).
b. For a positive scan:
i. Humeral head displaced in relationship to the glenoid at the GHJ.
ii. Must image GHJ with the glenoid and humeral head relationship NOT visualized in the same plane if dislocation IS present.
iii. Must sweep GHJ looking for effusion.
iv. GHJ effusion present and\or:
- If dislocation present, must specify if dislocation of humeral head is anterior or posterior.
Document as per CPoCUS guidelines for positives and negatives according to clinical indications:
a. GHJ effusion      + or –
b. GHJ dislocation   + 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 GHJ scans.
The introductory scans do not count towards certification and do not need to be determinate.
Logged scan requirements
- 7 GHJ 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 GHJ 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
Patient seated upright with shoulder fully exposed and arm dangling by their side or gently resting on their lap.
d. Probe orientation
Transverse plane with indicator directed toward patient’s right.
e. Probe grip
a. External landmark
ACJ at lateral end of clavicle.
b. Internal landmark
Bony processes of acromion and clavicle.
c. Relevant anatomy
Clavicle, AC joint, and acromion.
d. Area of interest
AC joint.
e. Adequate view
Centered ACJ with hyperechoic and well-defined clavicle (thin, bright white cortex)Â and acromion.
a. Image generation
i. Landmark
- Start scan by palpating ACJ externally and put probe on top of it in transverse.
- End scan when ACJ centered on screen.
ii. Optimize image
Adjust depth to centre image.
Increase gain if needed.
- Increase probe frequency to increase image resolution.
iii. Technique
Start scan by finding ACJ externally.
Place probe in transverse on top of clavicle close to ACJ.
- Slide probe medial to lateral to center ACJ on screen.
- Sweep to obtain hyperechoic and well-defined (thin and bright white) cortices of clavicle and acromion.
- Rotate if needed to center ACJ and have clavicle and acromion appear in line on screen (true transverse view of ACJ).
- Keep probe steady and perpendicular to the clavicle and acromion cortices (using your second hand might help in steadying scanning hand.
- End scan when ACJ is V-shaped and both bony cortices are well-defined.
- Measure ACJ widening from acromion to clavicle.
- Sweep ACJ to assess for effusion if desired and reassess with dynamic testing.
iv. Interrogate AOI
Measure distance between end of clavicle and acromion.
Assess for the presence of ACJ effusion.
b. Image interpretation
The following areas should be evaluated and a binary yes/no conclusion made:
i. ACJ widening? (YES/NO).
ii. ACJ effusion? (YES/NO).
a. Make sure to slide probe anterior to posterior to get best view of joint.
b. Imagine looking caudally (downwards) through the ACJ and orient probe accordingly.
c. Rotate probe slightly to image ACJ in its true transverse plane.
d. Sweep probe slightly to interrogate joint at 90 degrees (bony cortices should appear well-defined).
e. Use additional gel if area very tender.
a. Technique
i. Imaging ACJ in transverse oblique instead of true transverse can result in erroneous measurements.
b. Image interpretation
i. ACJ effusions presenting with the Geyser’s sign (when edematous bursa and fluid extrude out of the ACJ space with dynamic testing) can be missed if joint is only assessed through static testing
c. Clinical integration
i. ACJ widening
- Radiographic ACJ horizontal widening limit is 6 mm.
- Measurements of up to 10 mm can be found in normal individuals on US. Comparison with unaffected side may help with evaluation.
- Suggested ACJ measurement on US is called the AC index.
- AC Index = Unaffected side (mm) divided by affected side (mm). Ratio should be close to 1. The smaller the AC index, the larger the ACJ widening.
ii. ACJ effusion
- Ultrasound cannot reliably distinguish between a septic or an aseptic effusion. Clinical suspicion and correlation are paramount to making the right diagnosis and arthrocentesis is recommended to help refine diagnosis and treatment if clinician is worried about a septic joint.
iii. NERD ALERT! Many patients have ACJ OA that can DECREASE the width between acromion and clavicle! Osteophytes and ‘ratty’ bony cortices will help with diagnosis. US- guided corticosteroids injection of the ACJ in these circumstances can be considered.
a. When in doubt, compare with unaffected side.
b. Have patient hold 10-20 lbs weights on affected side to see if increased widening of ACJ.
c. In most 2nd and 3rd degree ACJ injuries, width exceeds 10-20 mm.
d. Dynamic testing by having patient cross their arm over to their contralateral shoulder can help with evaluation of ACJ widening.
e. Dynamic testing can also help assess for an ACJ effusion with presence of Geyser’s sign.
a. For a negative scan:
i. ACJ centred with acromion and clavicle cortices well defined.
ii. No widening of joint found.
iii. No effusion identified after dynamic testing.
b. For a positive scan:
i. ACJ centred with acromion and clavicle cortices well-defined and
ii. ACJ widening present or\and
iii. ACJ effusion identified.
Document as per CPoCUS guidelines for positives and negatives according to clinical indications:
a. ACJ widening      + or –
b. ACJ 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 ACJ scans.
The introductory scans do not count towards certification and do not need to be determinate.
Logged scan requirements
- 5 ACJ 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 ACJ 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).