TRAIN CERTIFY MAINTAIN
Acute Care Musculoskeletal (AC MSK)
CURRICULUM
Advanced skills for certification
a. Probe
Linear probe or high frequency probe of choice (10 MHz or more).
b. Knobology
i. Preset. Small parts or soft tissue.
ii. Depth. Minimal.
iii. Gain. Default. Adjust as needed.
c. Patient positioning
d. Probe orientation
e. Probe grip
Pencil grip or c-grip.
a. External landmark
b. Internal landmark
c. Relevant anatomy
Metacarpal, metacarpophalangeal joint
(MCPJ) space, proximal phalanx, medial phalanx, flexor tendon (FT), soft tissue.
d. Area of interest
e. Adequate view
a. Image generation
i. Landmark
- Start scan on metacarpal bone.
- Slide distally to proximal phalanx and again to medial phalanx.
- End scan when MCPJ space centred (MCPJ scan) or when FT centred on screen (FTS scan).
ii. Optimize image
- Use water bath to improve your view.
- Use minimal depth.
- Adjust probe frequency to its highest setting.
iii. Technique
- Start scan at metacarpal bone in long axis (probe marker towards patient’s head). Keep the bone cortex well-defined (bright white and thin) by sweeping or sliding side to side.
- Slide distally towards the proximal phalanx.
- Centre the MCPJ space on screen.
- Sweep to assess for effusion. Rotate probe 90 degrees into transverse to confirm impression.
- Re-centre and rotate probe back to sagittal
- Slide distally towards medial phalanx.
- Centre FT on screen.
- Assess for presence or absence of fluid surrounding the tendon by sweeping.
- Rotate probe 90 degrees to obtain transverse view and confirm impression.
- Compare with contralateral side or unaffected digit if unsure.
iv. Interrogate AOI
- Sweep MCPJ space looking for an effusion (MCPJ scan) in both axes.
- Sweep FT looking for fluid surrounding the tendon (FTS scan) in both axes.
b. Image interpretation
The following areas should be evaluated and a binary yes/no conclusion made:
i. Is there an effusion in the MCPJ space? (YES/NO).
ii. Is there fluid surrounding the FT? (YES/NO).
a. Use highest frequency possible.
b. Use water bath to improve visualization and alleviate the need to press on very tender areas.
a. Technique
i. Failure to centre joint can miss an effusion.
b. Image interpretation
i. Small amounts of fluid can be harder to detect. Compare to an unaffected digit.
ii. Cellulitis and cobblestone appearance of soft tissue can be mistaken for fluid around the FT. Remember your soft tissue layers.
c. Clinical integration
i. MCPJ scan:
- Impossible to distinguish on ultrasound between a septic or an aseptic effusion. Clinical correlation is paramount and tapping the joint recommended for final diagnosis if in doubt.
ii. FTS scan:
- FTS can also be non-infectious (ex: RA patient). Clinical correlation needed!
- Infectious FTS is a surgical emergency. Kanavel’s signs and clinical suspicion should guide your assessment. Call your hand surgeon early!
a. USE A WATER BATH to help with visualization.
b. Use gentle dynamic testing to locate FT. Can be used as Kanavel’s fifth sign!
c. Scrutinize area of maximal tenderness.
a. For a negative MCPJ scan:
i. MCPJ centred and swept in both axes and no effusion found.
b. For a positive MCPJ scan:
i. MCPJ centred and swept in both axes and effusion present.
c. For a negative FTS scan:
i. FT centred and swept in both axes and no fluid found around tendon.
d. For a positive FTS scan:
i. FT centred and swept in both axes and fluid around tendon present.
Document as per CPoCUS guidelines for positives and negatives according to clinical indications:
a. MCPJ space effusion    + or –
b. FTS                     + 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 MCPJ/FTS scans.
The introductory scans do not count towards certification and do not need to be determinate.
Logged scan requirements
- 5 hand MCPJ/FTS 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 MCPJ/FTS 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 small parts, or soft tissue.
ii. Depth. Start at depth of 5 cm. Adjust as needed.Â
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
Calcaneus, Achilles tendon, retro-calcanea bursa, retro-Achilles bursa (seen only in pathologic states), Kager’s fat pad, planters tendon (if present), gastrocnemius muscles, soles muscle.
d. Area of interest
e. Adequate view
a. Image generation
i. Landmark
- Start the scan just at the calcaneus in the sagittal plane with probe marker towards patient’s head.
- End the scan when the tendon is no longer well-defined and becomes part of the muscle bellies underneath.
ii. Optimize image
- Adjust depth to centre image.
- Increase probe frequency to increase image resolution.
iii. Technique
- Start the scan just at the calcaneus in LAX on the midline with ankle dorsiflexed.
- Centre calcaneus on screen by sliding probe side to side.
- Sweep or rock probe to image a well-defined calcaneus cortex.
- Slide probe cephalad to image Achilles tendon.
- Rock probe to obtain fibrillar, well-defined image of Achilles tendon fibers.
- Slide side to side to interrogate AOI at its insertion point (2-6 cm cephalad from calcaneus).
- Slide proximally keeping tendon centred and well-defined until myotendinous junction is reached.
- Slide side to side to interrogate myotendinous junction.
- Rotate probe 90 degrees in SAX and repeat interrogation.
- Slide caudally until insertion is reached and AOI interrogated.
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iv. Interrogate AOI
- Slide to interrogate well-defined centred tendon at 2 main sites of rupture in 2 planes.
- Insertion (2-6 cm from calcaneus).
- Myotendinous junction.
- Any area of discontinuity, loss of volume, swelling, hematoma or darkness within or around the tendon should prompt heightened scrutiny.
b. Image interpretation
The following areas should be evaluated and a binary yes/no conclusion made:
i. Evidence of Achilles tendon tear? (YES/NO).
a. Make sure to keep the tendon centred all throughout scanning.
b. Be prepared for anisotropy! Especially in and around the area close to the tendon insertion on the calcaneus.
c. Use dynamic testing to enhance tear detection.
d. Start scan at area of maximal tenderness if calf very swollen.
a. Technique
i. If ankle in plantar flexion, scanning the Achilles tendon will be very difficult. Dorsiflex patient’s ankle to 90 degrees as tolerated to flatten scanning surface.
b. Image interpretation
i.Tears can be filled with debris and be hard to assess. Dynamic testing of area by squeezing the calf (Thompson’s) or by flexing-dorsiflexing the ankle can help reveal partial and full thickness tears.
ii. Partial tears can be harder to diagnose than full-thickness tears.
- Remember that partial tears have:
- Well-defined hypoechoic or anechoic clefts.
- Incomplete disruption of tendon fibers.
- Tendon sheath anteriorly or posteriorly can remain intact.
- Full-thickness tears present with:
- Complete disruption of tendon architecture.
- Retraction of torn ends (shadowing artifact possible).
iii. It can be difficult to differentiate partial tears from tendonitis. Characteristics suggesting a tear are:
- Hypoechoic or anechoic zone disrupting tendon.
- Retraction of torn ends in complete tears.
- Heterogenous aspect of hemorrhage.
- Jagged edges and refraction shadowing at the retracted torn tendon stumps.
- Neovascularity seen on color Doppler from chronic wear can be present in both entities.
iv. Up to 3 mm of fluid can be seen in the retrocalcaneal bursa in a normal patient. When in doubt, compare with unaffected side.
v. Plantaris tendon can sometimes be seen far field in the presence of a complete Achilles tears (up to 20% of patients have a plantaris tendon).
vi. Retro-Achilles bursa (near field to Achilles tendon) is seen only in pathological states.
vii. Tendon AP diameter should only be measured in SAX.
- Normal is less than 2 cm in adults.
- Tendon thickening is found in chronic wear diseases.
viii. NERD ALERT! Size of tear. Once a full-thickness tear has been found, you can measure size of tear by measuring separation between the retracted ends with calipers in LAX. You can also measure cm from tear found to tendon insertion. Fluid in the bursas can be acute or chronic. Clinical correlation needed!
c. Clinical integration
i. Achilles tears found on POCUS warrant a rapid orthopedic consult and immobilization of patient’s leg according to local practice.
ii. Partial tears may be hard to detect even with ultrasound. Clinical judgment reigns supreme and diagnostic adjuncts are recommended when clinical suspicion remains high.
a. Put lots of US gel to ensure good probe contact and minimize applied pressure to tender areas.
b. Apply higher scrutiny to area of maximal tenderness.
c. Start scan at area of maximal tenderness if calf very swollen.
a. For a negative scan:
i. Must image a centred and well-defined Achilles tendon from its calcaneal insertion to its myotendinous junction in both long and short axis.
ii. Must interrogate AOI completely at 2 most frequent rupture points: 2-6 cm from insertion and myotendinous junction.
iii. No tendon tear identified.
b. For a positive scan:
i. Must image a centred and well-defined Achilles tendon from its calcaneal insertion to its myotendinous junction in both long and short axis.
ii. Must interrogate AOI completely at 2 most frequent rupture points: 2-6 cm from insertion and myotendinous junction.
iii. A tendon tear is identified.
Document as per CPoCUS guidelines for positives and negatives according to clinical indications:
a. Achilles tendon tear    + 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 Achilles scans.
The introductory scans do not count towards certification and do not need to be determinate.
Logged scan requirements
- 8 Achilles 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 1 scan 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 AC MSK Achilles 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).