Wrist Arthrocentesis

Anatomy and Physiology

Anatomic structures to consider while performing wrist arthrocentesis are the following: 

• Distal radius
• Anatomic snuffbox
• Extensor carpi radialis brevis
• Extensor pollicis longus

The joint space can be palpated distal to the radius and ulnar to the anatomic snuffbox on the dorsal aspect of the wrist, avoiding extensor carpi radialis brevis and extensor pollicis longus. Additionally, the joint space can be approached from the ulnar aspect. From the ulnar approach, space can be palpated distally to the distal ulna.[1]

Indications

Wrist arthrocentesis can be both therapeutic and diagnostic. Indications for procedure include:

• Septic arthritis (including its response to treatment)
• Acute monoarticular arthritis
• Inflammatory joint effusion
• Intra-articular injection of medications
• Aspiration of large painful joint effusions
• Recurrent aspiration[1][2]

Contraindications

There are no absolute contraindications for wrist arthrocentesis. Relative contraindications include overlying cellulitis, bacteremia, overlying skin lesions, a joint prosthesis (preferably using aseptic technique by surgeons), unstable joint, and acute fracture. Coagulopathic/bleeding disorders, thrombocytopenia, or anticoagulant use should be considered prior to the procedure. The procedure can be performed with precautions by reversal agent administration or addressing the specific coagulopathy.[1][2]

Equipment

General equipment includes:

• Betadine or chlorhexidine
• Sterile gloves/drape
• Sterile gauze
• Skin marking pen
• Lidocaine
• 25-27 gauge sterile needle for local anesthesia
• 20-21 gauge sterile needle for aspiration
• 2-5 ml syringes 
• Specimen tubes[1][3]

A reciprocating syringe can be used in place of a conventional syringe resulting in improvement of physician performance in arthrocentesis. The reciprocating syringe allows the physician to perform the procedure one-handed while reducing significant pain and procedure time.[4]

The utility of ultrasound has shown success in the evaluation of joint effusions and arthrocentesis. With its ability to identify joint anatomy and fluid collections, ultrasound improves aspiration rates and results in fewer complications, especially in small joints.[5][6][7][8]

Personnel

Wrist arthrocentesis can be performed by medical care professionals in the emergency department or in an outpatient setting. This procedure does not require additional personnel for assistance.

Preparation

Informed consent must be obtained from the patient prior to performing the procedure. The patient should be placed in a supine position with the wrist slightly palmar flexed. A rolled sheet or towel can be placed under the wrist for proper positioning. All landmarks are identified with the needle site marked. The area can be cleaned with either betadine or chlorhexidine. Lidocaine 1% or 2% can be used for local anesthetic. However, some clinicians choose to use a topical ethyl chloride alone or no local anesthesia at all.

Technique or Treatment

The landmarks need to be palpated prior to cleansing the skin. The joint space can be palpated distal to the distal radius and ulnar to the anatomic snuffbox, making sure to avoid the associated extensor tendons. For the radial approach, the needle should be inserted dorsally perpendicular to the skin. If the needle hits the bone, then it should be withdrawn and redirected towards the thumb.[1]

The ulnar approach uses the same positioning. The joint space in this approach is identified by palpating distal to the distal ulna. The needle is inserted dorsally in a radial direction.[1]

Upon entering the joint space, a pop or give is felt. The synovial fluid can now be withdrawn. Some resistance might be noted determined by the needle size, viscosity of the fluid, amount of fluid, and presence of fibrin clots. If resistance is noted, rotating the needle or withdrawing it slightly could be helpful. If medication is to be injected, the syringe has to be removed while keeping the needle secure and the medication injected. Once completed, the needle should be removed, and light pressure should be applied to the insertion site. The synovial fluid obtained should be transferred to specimen tubes testing for cell count, glucose, protein, LDH, lactate, crystals, and culture.

Ultrasound is a helpful tool to identify joint effusions and perform arthrocentesis.[7][8] When using an ultrasound, the patient is positioned in a similar palmar flexed fashion. The ultrasound probe should have a sterile probe cover to ensure proper sterile technique. The ultrasound probe is placed in a sagittal view over the distal radius until the joint space between either radius and scaphoid or radius and lunate can be noted. A hypoechoic fluid collection above the carpal bone will be noted if an effusion is present. Using an in-plane distal to proximal approach, the needle should be advanced while aspirating until the needle tip can be seen in the effusion. Aspirating will cause a decrease in the effusion size on ultrasound.

Complications

Complications can arise from the procedure itself or as an adverse effect to the compound injected into space.

Procedural complications can include damage to surrounding structures such as tendon rupture or local nerve injury, infection such as septic arthritis, pain, hemarthrosis, and re-accumulation of effusion. Septic arthritis is a rare but significant complication. Using a sterile technique minimizes the risk; however, the patient may be placed on prophylactic antibiotics if the risk is determined to be higher.[2]

Possible corticosteroid injection complications include procedural complications and allergic reaction, diabetic hyperglycemia, steroid flare, tendon, or local skin atrophy.[2]

Clinical Significance

Arthrocentesis is both a therapeutic and diagnostic procedure. It can be performed for pain relief from the drainage of large effusions, injection of medications, or to obtain a synovial fluid for testing. Learning an appropriate technique specific to the joint minimizes the risk of complications.

While history and physical exams are helpful adjuncts, the analysis of synovial fluid has the highest effect on the diagnosis of septic arthritis. The likelihood and sensitivity for the diagnosis of septic arthritis are as follows:

• White blood cell count (WBC) of more than 100,000 microliters (positive likelihood ratio 28, sensitivity 13-40)
• WBC more than 50,000 (positive likelihood ratio 7.7, sensitivity 50-70)
• WBC more than 25,000 (positive likelihood ratio 2.9, sensitivity 63-88)
• PMN more than 90% (positive likelihood ratio 3.4, sensitivity 57-92)
• Low glucose (positive likelihood ratio 3.4, sensitivity 38-64)
• Protein more than 3 g/dL (positive likelihood ratio 0.90, sensitivity 48-50)
• Lactate dehydrogenase level (LDH) more than 250 units/L (positive likelihood ratio 1.9, sensitivity 100)[9]

Synovial fluid analysis showing elevated WBC count or a high percentage of polymorphonuclear cells significantly increases the likelihood of a diagnosis of septic arthritis resulting in orthopedic consultation, antibiotic therapy, and admission.[9] Septic arthritis can be confirmed with a positive Gram stain and culture, which will help guide antibiotic therapy. The most common organism for wrist infection is Staphylococcus aureus. There is no organism identified in up to 40% of cases, possibly secondary to an inadequate amount of synovial fluid for analysis.[10][11]

Crystalline arthropathy affects the wrist joint frequently. The presence of crystals in synovial fluid does not rule out septic arthritis. The type of crystal formation can help differentiate between inflammatory joint disease. In gout, synovial fluid is positive for negatively birefringent urate crystals, whereas pseudogout shows positively birefringent calcium pyrophosphate crystals.[10][11]

Enhancing Healthcare Team Outcomes

Wrist arthrocentesis is a procedure that can be performed by an emergency physician, primary care physician, orthopedic surgeon, or nurse practitioner. Complications can be limited by understanding anatomy, using a sterile technique, and appropriate post-procedural care.

The procedure is usually performed in the emergency department or outpatient setting; further management is determined by the results of the synovial fluid analysis. Delaying the start of antibiotic therapy for suspicion of septic arthritis can be harmful. While many organisms can be the cause, an increased likelihood of Staphylococcus aureus as the most common cause should guide antibiotic choice.[10][11] Gram stain and culture results can assist pharmacists further with appropriate antibiotic coverage. 

Management of confirmed septic arthritis includes orthopedic consultation for joint aspiration and/or surgical drainage with antibiotics and temporary immobilization. Recovery has been shown to be good to excellent when surgical drainage has been performed within 10 hours of diagnosis. The standard surgical management involves open arthrotomy. Arthroscopic drainage has been shown to be beneficial as well due to shorter hospital stays, better joint visualization, and smaller incision sites. Needle aspiration is also a viable option; however, some surgeons suggest it should be used if the patient cannot undergo surgical intervention. Others have found serial needle aspiration with medical management to be a more beneficial management strategy for the patient. The procedure can be done bedside, require decreased staff and equipment, and shorter hospital stays without a difference in long-term outcomes.[10][11][12]

Nurses are critical members of the interprofessional team. Nurses will provide post-procedural/post-operative care by monitoring vital signs, assessing for evidence of wound infection, or worsening pain, and are vital for patient education. 

Interprofessional collaboration has shown to be cost-effective as well as increase staff satisfaction and provide a better understanding of patient care.[13] [Level 2] Implementing interprofessional interventions such as multidisciplinary meetings or interdisciplinary rounds could further improve healthcare processes and outcomes such as patient care and length of stay.[14] [Level 2]