Equipment
Aspiration of the wrist does not require specialized equipment.
Sterile technique must be followed during the procedure. Some experienced operators do not use sterile gloves. In this case, a no-touch technique is employed, in which palpation and marking of the puncture site precede application of the antiseptic. After the initial marking, the area is not touched. If the no-touch technique is used, nonsterile gloves should still be worn to protect the operator. Relatively inexperienced operators should wear sterile gloves.
A 20-gauge needle should be used. For septic arthritis, an 18-gauge needle may occasionally be required, if the fluid is too viscous to allow aspiration through a smaller needle.
A 5-mL syringe is usually the most appropriate size. A "reciprocating syringe" has been developed to improve procedural performance. Some randomized data suggest that these syringes have benefits when compared with conventional syringes for joint aspiration. [12]
Forceps may be useful for holding the needle when changing the syringe between aspiration of the joint and injection of medication into the synovial cavity.
Patient Preparation
Anesthesia
For local anesthesia (see Local Anesthetic Agents, Infiltrative Administration), the skin and subcutaneous tissues may be infiltrated down to the level of the periarticular lesion or joint capsule with 1% or 2% lidocaine via a small needle (25 or 27 gauge). However, many experienced clinicians prefer to use topical ethyl chloride or no anesthetic at all. This is often appropriate for joint aspiration because anesthetizing the capsule is difficult. A single quick needle thrust may be much less painful than the administration of local anesthesia.
Positioning
The patient should be placed in a comfortable supine or recumbent position. This enhances relaxation and guards against possible fainting. The wrist should be slightly palmarflexed to facilitate the performance of the procedure.
The skin must be carefully cleaned with an antiseptic agent. Before this is done, bone and other landmarks must be identified by means of palpation, and the needle site must be marked (eg, with a thumbnail imprint in the skin or a skin marker).
-
Injection of wrist joint.
-
Arthrocentesis of wrist: medial and lateral approaches.
Tables
Parameter |
Normal |
Osteoarthritis |
Rheumatoid and Other Inflammatory Arthritis |
Septic Arthritis |
Gross appearance |
Clear |
Clear |
Opaque |
Opaque |
Volume, mL |
0-1 |
1-10 |
5-50 |
5-50 |
Viscosity |
High |
High |
Low |
Low |
Total white blood cell count, cells/μL |
< 200 |
200-10,000 |
500-75,000 |
>50,000 |
Polymorphonuclear cells, % |
< 25 |
< 50 |
>50 |
>75 |
