TRAIN CERTIFY MAINTAIN
Acute Care Musculoskeletal (AC 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).