Trapeziometacarpal Joint (TMC joint or 1st CMC joint) Injection
|Trapeziometacarpal Joint (TMC joint or 1st CMC joint) Injection|
|Needle||25-27 gauge 1 inch needle|
Indications and Efficacy
TMC joint injection may be indicated with failure of first line treatments to treat chronic pain e.g. fromosteoarthritis, and/or to ascertain whether the joint is a significant pain generator.
- Topical steriliser
- 3mL syringe with a 25 gauge 1 inch needle
- 0.5mL 1% lidocaine
- 0.5mL of 40mg/mL (20mg) triamcinolone or equivalent
- Ultrasound machine if using
The following is a technique described by Umphrey et al. In their cadaver study they found an accuracy of 94% (16 out of 17 cadavers). One of the cadavers had contrast in the STT joint with the operator deviating from the below technique and had the field of view set too narrow.
- Position forearm supinated, with the patient's digits directed towards the clinician
- Identify the TMC joint
- Palpate the volar-radial aspect of the thumb from distal to proximal
- Place the transducer parallel to the thumb metacarpal along its volar-radial aspect
- Slowly advance the transducer proximally under the TMC joint is visualised as a hypoechoic cleft between the base of the thumb metacarpal and the distal aspect of the trapezium
- Move the transducer to the centre of the joint on the screen
- Needle approach
- Use an out-of-plane approach
- Centre the needle directly perpendicular to the transducer
- Angle the needle 30 to 45 degrees relative to the transducer
- Advance the needle under direct sonographic visualisation into the TMC joint cleft until a soft "pop" and loss of resistance is felt representing capsular penetration.
- Inject 0.5-1mL of solution
- Note, in the presence of severe osteophytosis, the approach may need to be adjusted slightly.
Ultrasound transducer over TMC joint. Needle is positioned on the volar side of the transducer at the midpoint of the transducer’s long axis. Path of entry is 30° to 45° relative to the transducer.
Ultrasound-guided injection of the TMC joint. A hypoechoic cleft is visualised between the trapezium (left) and first metacarpal (right) defining the joint space. The needle tip is visualised in the centre of the joint space.
Accuracy is 100%. The TMC joint is small and so the contrast needed significantly reduces the volume of injected medication which could reduce the therapeutic outcome.
Landmark guided injection accuracy is 58-100%. Some experienced clinicians may be able to inject the joint via landmark guidance nearly 100% of the time.
- Position the patients hand in a mid supinated position with the thumb up. Ask the patient to apply traction to their thumb.
- Identify the joint by finding a gap of joint space at the apex of the snuff box on the dorsum of the wrist, between the extensor pollicis longus and extensor pollicis brevis tendons.
- Moving the thumb can help better identify the joint
- Insert the needle perpendicularly into the gap on the ulnar side of the extensor pollicis brevis tendon to avoid the radial artery.
- It may be necessary to anaesthetise the capsule before intraarticular injection
- If the needle doesn't enter the joint then walk the needle until it enters the space, feeling a distinct pop as it penetrates the capsule of the joint.
- Inject the solution
Radial artery puncture, skin atrophy, infection
Tape the thumb using a spica technique for a few days. Then begin gentle active and passive mobilisation exercises within pain-free range. Advise to contact you if any signs of infection.
- Reviews from the last 7 years: review articles, free review articles, systematic reviews, meta-analyses, NCBI Bookshelf
- Articles from all years: PubMed search, Google Scholar search.
- TRIP Database: clinical publications about evidence-based medicine.
- Other Wikis: Radiopaedia, Wikipedia Search, Wikipedia I Feel Lucky, Orthobullets,