Version July 2025
INTRODUCTION —
Joint aspiration (ie, arthrocentesis) and glucocorticoid injections are used for diagnostic and therapeutic purposes in the care of children with arthritis.
This topic reviews the general indications, techniques, and complications of intraarticular aspiration and glucocorticoid injection in children. More information on the approach to these procedures in adults and the use of procedural ultrasound guidance is provided separately:
●(See "Joint aspiration and injection in adults: Indications and technique".)
●(See "Joint aspiration and injection in adults: Complications".)
●(See "Intraarticular and soft tissue injections: What agent(s) to inject and how frequently?".)
The use of joint aspiration and injection in the diagnosis and treatment of various conditions is presented in the respective disease-specific topics.
APPROPRIATE USE OF JOINT ASPIRATION AND INJECTION —
Joint aspiration (ie, arthrocentesis) in children is used primarily to evaluate for infection and can also provide temporary relief from large effusions through decompression of the joint space. Intraarticular glucocorticoid injections are used in the management of many forms of inflammatory arthritis; however, they should not be given if there is a concern for an active infection affecting the area being injected (eg, septic arthritis, overlying cellulitis, bacteremia).
Indications for joint aspiration — Clinical scenarios in which joint aspiration and synovial fluid studies are especially helpful include the following:
●Suspected bacterial arthritis (most common) – Joint aspiration in children is most commonly used to help differentiate septic arthritis from other causes of joint swelling (eg, inflammatory arthritis), based on synovial fluid analysis (see "Bacterial arthritis: Clinical features and diagnosis in infants and children", section on 'Synovial fluid'). Of note, some forms of bacterial arthritis require additional testing to confirm the causative organism (eg, Lyme arthritis, tuberculous arthritis). (See "Diagnosis of Lyme disease", section on 'Early disseminated and late Lyme disease' and "Bone and joint tuberculosis", section on 'Biopsy and culture'.)
Patients with bacterial arthritis classically have acute-onset monoarthritis affecting the lower extremity, accompanied by fever. However, presentations can vary widely based on the causative organism and patient factors that may mask presenting features (eg, patients taking immunosuppressive medications). It is therefore important to maintain a high index of suspicion for bacterial arthritis, even in patients with established inflammatory arthritis. (See "Bacterial arthritis: Clinical features and diagnosis in infants and children", section on 'Clinical features'.)
●Symptomatic relief of large joint effusions – Aspirating fluid from a significantly swollen joint can provide temporary therapeutic relief by decompressing the joint and therefore reducing activation of pressure-sensing nociceptors that innervate the joint capsule [1]. However, fluid is likely to rapidly reaccumulate without targeted treatment of the underlying condition. For children with established inflammatory arthritis, aspiration of large joint effusion is often paired with an intraarticular glucocorticoid injection. For those with septic arthritis, the best options for fluid removal include surgical drainage via either open arthrotomy or serial aspirations [2], particularly if the aspirated synovial fluid is purulent [3,4]. (See "Bacterial arthritis in infants and children: Treatment and outcome", section on 'Drainage'.)
●Evaluating for alternative diagnoses in suspected inflammatory arthritis – Arthrocentesis is of limited diagnostic value in children with suspected inflammatory arthritis. As an example, patients with juvenile idiopathic arthritis (JIA) can usually be diagnosed based on a combination of history, physical examination, and other diagnostic testing. However, when these factors are insufficient to establish the diagnosis, arthrocentesis can help distinguish inflammatory arthritis from noninflammatory causes of joint swelling, such as orthopedic injuries (eg, hemarthrosis) and, more rarely, leukemic synovitis and Charcot arthropathy. Synovial fluid analysis cannot reliably distinguish different subtypes of inflammatory arthritis. (See "Evaluation of the child with joint pain and/or swelling", section on 'Differential diagnosis'.)
●Suspected gout (rare) – Gout can be diagnosed based on the presence of monosodium urate (MSU) crystals in the synovial fluid. This is a common indication for joint aspiration in adults; however, the condition is rare in children and should primarily be suspected when there are strong risk factors for developing gout (eg, advanced kidney function impairment). (See "Gout: Clinical manifestations and diagnosis".)
Indications for joint injection — Intraarticular glucocorticoid injections are often used to treat inflammatory arthritis [5-9], since they offer rapid control of inflammation in the injected joint and spare patients from the adverse effects of systemic glucocorticoids. They are most commonly used as part of the initial management of children with oligoarticular JIA and are also used in other forms of JIA to treat focal disease while initiating or adjusting systemic medication. The use of intraarticular glucocorticoids as adjunctive therapy in children with JIA is discussed in the respective disease-specific treatment topics:
●(See "Oligoarticular juvenile idiopathic arthritis", section on 'Initial treatment'.)
Contraindications — Relative contraindications to joint aspiration include infection of the overlying skin or soft tissue. In such cases, arthrocentesis may still be accomplished by adapting the approach to avoid the affected area (eg, with the use of ultrasound guidance).
For intraarticular glucocorticoid injections, contraindications include the following:
●Concern for septic arthritis
●Infection of the overlying skin or soft tissue
●Bacteremia [10]
●Allergy to the medication being injected
●Anticipated joint replacement of the affected joint in the next three months (rare in children)
Patients who have an increased risk of bleeding (eg, patients taking anticoagulation or with significant thrombocytopenia) can often safely undergo arthrocentesis but may need some additional measures to lower the risk. (See 'Patients with an increased risk of bleeding' below.)
PREPROCEDURAL MANAGEMENT —
Prior to arthrocentesis, we perform a comprehensive joint examination and patient history to help determine the anticipated procedural approach and the need for sedation and/or image guidance.
Patient evaluation — Prior to performing an arthrocentesis, we perform a comprehensive musculoskeletal examination, with particular attention to the affected joint, adjacent joints, and surrounding tissues. This can help identify potential technical challenges (eg, joint contractures), as well as findings that suggest certain time-sensitive diagnoses. As examples, children with early osteomyelitis may develop a sterile, sympathetic effusion (in which the synovial fluid appears benign) in an adjacent joint; similarly, children with an underlying malignancy (eg, leukemia) may also develop sympathetic effusions. (See "Hematogenous osteomyelitis in children: Clinical features and complications", section on 'Clinical features' and "Overview of common presenting signs and symptoms of childhood cancer", section on 'Bone and joint pain'.)
In addition, we obtain a thorough clinical history (eg, surgical, dental, obstetric, traumatic injury, medications, family) to identify factors that may increase the risks of the procedure. If we identify a potential increased risk of bleeding, then we obtain laboratory testing of clotting function [11]. (See "Approach to the child with bleeding symptoms", section on 'Initial laboratory evaluation' and "Procedural sedation in children: Approach", section on 'Contraindications and precautions'.)
Obtaining informed consent — Prior to any procedure, the provider must obtain informed consent/assent from the patient and/or guardian as appropriate for the patient's age. We discuss the reason for the procedure, alternative options, risks of not doing the procedure, anticipated benefits, and potential complications (see 'Complications' below). More information on procedural consent is provided elsewhere. (See "Informed procedural consent".)
When to use procedural sedation — Although many children tolerate arthrocentesis with local anesthesia and appropriate reassurance in an outpatient setting, some may require procedural anxiolysis, moderate or deep sedation, or, rarely, general anesthesia. There is no standardized method for delivering anesthesia to children undergoing joint injections [12]. However, we typically offer options beyond local anesthesia in the following scenarios [13-15]:
●Children who require multiple joint injections, especially in a patient with lower pain tolerance and/or limited ability to cooperate with the procedure.
●Children with underlying neurologic or psychiatric disorders (eg, autism spectrum disorder, posttraumatic stress disorder, conduct disorders, generalized anxiety disorder) that may limit tolerance of nonsedated injections. These patients are at risk for experiencing significant stress during a procedure, which may affect their trust in their clinician and willingness to undergo future procedures.
●Children who have had a prior negative experience with nonsedated procedures.
For children undergoing intraarticular glucocorticoid injections into larger joints (eg, the knee), a minimal anxiolysis/sedation (MAS) protocol is an alternative to general anesthesia. This protocol uses Child Life services, a topical numbing medication, and nitrous oxide and/or intranasal fentanyl administered by a sedation service. One study noted a 33 percent reduction in operating expenses when intraarticular injections were performed in this manner versus in the operating room [15].
Types of procedural sedation are reviewed in greater detail separately. (See "Procedural sedation in children: Approach".)
When to use image guidance — Imaging modalities that can guide accurate intraarticular needle placement for aspiration and/or injection include ultrasonography and, less commonly, computed tomography (CT) and fluoroscopy [16,17]. Potential benefits of performing joint aspiration or injection with imaging guidance include confirmation of an effusion, precise localization of fluid pockets to target, and identification of important structures to avoid (eg, major blood vessels and nerves). These advantages make procedures shorter, less painful, and more accurate [18], which is especially important in children who often have a more limited capacity to tolerate painful procedures compared with adults. However, potential disadvantages include increased healthcare costs and, for ultrasonography, limited availability of trained ultrasonographers.
In general, we use ultrasound guidance rather than CT or fluoroscopy to avoid radiation exposure. We routinely use imaging guidance for aspiration or injection of the following areas:
●Joints that are difficult to access based solely on direct palpation of landmarks, including the temporomandibular [19], shoulder, hip, ankle, sternoclavicular, and sacroiliac joints.
●Joints with several spaces that may not communicate with each other (eg, wrist and ankle joints).
●Tenosynovial effusions.
Additionally, we consider using ultrasound guidance for aspiration of other joints in children when a trained ultrasonographer is readily available as image guidance decreases procedural pain and produces more long-lasting results.
More information on the use of musculoskeletal ultrasonography, including the approach to needle placement in specific joints, is provided separately. (See "Musculoskeletal ultrasonography: Guided injection, aspiration, and biopsy of joints and related structures".)
Patients with an increased risk of bleeding — We implement the following measures to reduce the risk of bleeding in certain patient populations:
●Significant thrombocytopenia – There is a low risk of hemorrhage in patients with significant thrombocytopenia (eg, <50,000/microL). For patients with a critically low platelet count who have an urgent reason to undergo a joint aspiration (eg, concern for septic arthritis), we suggest consulting with a pediatric hematologist and giving a platelet transfusion prior to the procedure. (See "Approach to the child with unexplained thrombocytopenia", section on 'Platelet count and bleeding risk'.)
●Use of anticoagulation – Based on data from adults, most patients taking anticoagulation can still safely undergo joint aspiration or injection [20,21]; however, we counsel patients about the risk of bleeding and use smaller-gauge needles (eg, 22-gauge). We also consider delaying the procedure for patients who are supratherapeutic on warfarin (eg, international normalized ratio [INR] >3.0). (See "Joint aspiration and injection in adults: Indications and technique", section on 'Patients on anticoagulation'.)
●Hemophilia – Patients with hemophilia may require additional precautions for arthrocentesis, such as administration of factor concentrate, which is discussed in detail elsewhere. (See "Acute treatment of bleeding and surgery in hemophilia A and B", section on 'Arthrocentesis (typically not used)'.)
EQUIPMENT AND MEDICATIONS —
Supplies for joint aspiration and/or injection are outlined in the table (table 1) and discussed in more detail below.
Needle and syringe size — Joint aspiration requires a relatively larger-bore needle compared with joint injection, due to the high viscosity of synovial fluid. In addition, the optimal needle gauge and length for joint aspiration and/or injection depends primarily upon the size of the joint, as well as the degree of the effusion and patient body habitus [22]:
●Small joints (eg, wrists, fingers, toes) – For aspiration or injection such joints, we typically use a 25- or 27-gauge needle. Small joints are superficial; when injecting glucocorticoids, using a relatively smaller-bore needle minimizes the risk of skin atrophy and depigmentation that may result from extravasation of glucocorticoid. The needle length may be 1.25 inches long or shorter, depending upon the joint.
●Medium and large joints (eg, shoulder, elbow, hip, knee, ankle) – For aspiration of such joints, we typically use a 20-gauge, 1.5 inch needle. Hip and shoulder aspiration and injection may require longer needles (eg, 2.5- or 3.5-inch spinal needles). If we are aspirating a large knee effusion or a Baker's cyst, then we use a larger-bore needle (ie, 18- or 20-gauge) to facilitate aspiration of synovial fluid, which is often gelatinous and difficult to extract.
For joint aspiration, we pick the syringe based on the anticipated amount of fluid to be aspirated (eg, 5 mL for diagnostic purposes, 20 to 50 mL for therapeutic relief of large effusions). Larger syringes offer a greater amount of suction, which can facilitate aspiration. For injection of intraarticular glucocorticoids, we choose the syringe size selected based on the amount of medication being delivered.
In addition to the above considerations, it is important to recognize that larger syringes and smaller-bore needles produce a higher perceived resistance when depressing the plunger of the syringe. This increased resistance can be misinterpreted as the needle tip being misdirected into a tendon, which provides similarly higher resistance. Providers may therefore benefit from consistently using the same syringe and needle size when possible, so that they become familiar with the expected amount of resistance.
Intraarticular glucocorticoids — We use triamcinolone hexacetonide for intraarticular glucocorticoid injections when it is available; however, triamcinolone acetonide is used most often due to its widespread availability. For smaller joints, we often use methylprednisolone acetate, which is available at a higher concentration. Dosing varies based on the child's age and weight, joint being injected, size of the medication vial, and provider experience. We do not mix glucocorticoids with a local anesthetic (eg, lidocaine) given the risk of chondrotoxicity.
Choice of glucocorticoid — We use triamcinolone hexacetonide when it is available. Otherwise, we use triamcinolone acetonide or, for smaller joint injections, methylprednisolone acetate, which is available at a higher concentration.
Data directly comparing glucocorticoid preparations for intraarticular injections are very limited. Our preference for triamcinolone hexacetonide is based on its longer duration of action and lower risk of developing adverse systemic glucocorticoid effects (eg, adrenal suppression) compared with triamcinolone acetonide [23-28], and greater efficacy compared with methylprednisolone acetate [24,27,29]. This favorable profile is likely related to triamcinolone hexacetonide being a larger molecule with lower solubility; it therefore has a slower release from the joint into systemic circulation. However, the availability of triamcinolone hexacetonide is very limited in the United States, leading to more widespread use of triamcinolone acetonide and methylprednisolone acetate. Notably, other medications with the same chemical formulation have been imported to the United States from Europe under the Food and Drug Administration (FDA) Personal Importation Program (PIP).
Methylprednisolone acetate is available in more concentrated forms, which makes it an appealing choice for the injection of small joints. In addition, it is more soluble and, based on limited data, may be associated with a lower risk of subcutaneous atrophy compared with other glucocorticoid formulations [30].
Key studies comparing types of intraarticular glucocorticoid injections in pediatric patients include the following:
●Two trials have found that response rates are higher for patients with juvenile idiopathic arthritis (JIA) who are treated with triamcinolone hexacetonide compared with triamcinolone acetonide [24,27]. As an example, a double-blind trial identified 37 patients with JIA who had at least one pair of symmetrically affected joints; one joint in the pair was randomly assigned to receive intraarticular triamcinolone hexacetonide (1 mg/kg), while the other received triamcinolone acetonide (2 mg/kg) [24]. Six months after injection, there was a higher response rate in the joints injected with triamcinolone hexacetonide compared with ones injected with triamcinolone acetonide (81 versus 53 percent); these differences persisted at 12 and 24 months.
●In a retrospective review of 79 patients with JIA, the likelihood of prolonged remission for two years after intraarticular glucocorticoid injection was higher for the 34 patients who received triamcinolone hexacetonide compared with those who received methylprednisolone acetate [29].
Dosing and frequency — Intraarticular glucocorticoid dosing is based on the child's age and weight, the size of the affected joint, the size of the medication vial, and the provider's personal experience [26]. General categories of joint sizes include small (eg, hands, feet), medium (eg, elbows, wrists, ankles), and large joints (eg, shoulders, hips, knees). There are no established dosing guidelines for intraarticular glucocorticoid injections in JIA. More information on specific agents is provided below:
●Triamcinolone hexacetonide – Triamcinolone hexacetonide doses vary according to joint: 1 mg/kg up to 40 mg for large joints including the knees, hips, and shoulders; 0.75 mg/kg up to 30 mg for ankles and elbows, 0.5 mg/kg up to 20 mg for wrists; and 5 to 10 mg for the small joints of the hands and foot [25,31]. The maximum dosing per joint of triamcinolone hexacetonide is often used regardless of the age or weight of the patient; this is likely due to the improved adverse effect profile of this drug compared with triamcinolone acetonide, which reflects the slower release of this drug from the joint into systemic circulation [32].
●Triamcinolone acetonide – We typically use triamcinolone acetonide intraarticularly at a dose of 2 mg/kg, up to a maximum dose of 40 mg for medium joints or 80 mg for large joints [31]. In two small observational studies, this dosing led to longer-lasting remission compared with lower dosing [25,26]. Alternatively, triamcinolone acetonide may be given at a lower dose of 1 mg/kg, up to a maximum dose of 5 to 10 mg for small joints, 20 mg for medium joints, and 40 mg for large joints.
●Methylprednisolone acetate – Methylprednisolone acetate is available in more concentrated forms, enabling more medication to be administered into the joint. It is generally used at doses of 5 to 10 mg for small joints and 20 to 40 mg in the subtalar and intertarsal joints [28,31]. We reserve its use for smaller joints where triamcinolone acetonide could leak and cause subcutaneous atrophy.
Whenever possible, we use single-dose medication vials rather than multidose vials to reduce the risk of bacterial contamination [33].
There are also no established guidelines about the number of glucocorticoid joint injections patients with JIA can receive. Most children receive multiple joint injections to more expediently treat their disease while awaiting systemic therapy to take clinical effect [6].
Avoidance of mixing with local anesthetic — We do not routinely mix local anesthetics (eg, lidocaine) with glucocorticoids for intraarticular injections. While such agents can offer limited benefits (eg, temporary pain relief), in our practice we find that they are typically unnecessary and therefore do not merit the potential associated risks, such as chondrotoxicity. However, other UpToDate contributors do mix glucocorticoids with local anesthetic for intraarticular injections in adults. (See "Intraarticular and soft tissue injections: What agent(s) to inject and how frequently?", section on 'Should the glucocorticoid be mixed with a local anesthetic?'.)
Studies on the potential risks of including local anesthetics in intraarticular injections are summarized below:
●Chondrotoxicity – Multiple in vitro and in vivo studies in animal and human tissues have demonstrated a chondrotoxic effect of local anesthetics, which may be present even when using low doses of lidocaine [34,35]. This risk appears to be compounded by coadministration of glucocorticoids [34]. Data are mixed on whether there is an effect after a single intraarticular injection [35,36]. Notably, data are extremely limited about the long-term clinical effects of intraarticular anesthetics in patients with inflammatory arthritis, including children.
●Decreasing sensitivity of synovial fluid cultures – Synovial fluid cultures that contain lidocaine may be less sensitive to detecting septic arthritis because of the lidocaine and methylparaben preservatives [37].
TECHNIQUE —
Both arthrocentesis and intraarticular glucocorticoid injections should be performed by experienced practitioners following the preprocedural management approach outlined above. (See 'Preprocedural management' above.)
Local anesthesia — Various types of local anesthetics are available for children undergoing joint aspiration or injection. There is no standardized method for delivering anesthesia to children undergoing joint injections [12]. For ultrasound-guided injection without aspiration, administration of lidocaine via jet injection (ie, a "J-tip") at the site of needle entry is typically sufficient since ultrasound facilitates an accurate and therefore efficient and less painful procedure. Otherwise, for injection without imaging or any type of joint aspiration, we typically inject lidocaine subcutaneously along the anticipated track. While subcutaneous lidocaine injections are associated with a burning sensation, this strategy may provide more effective pain relief related to the larger-bore needles required for aspiration and the potentially longer time or needle redirection required for procedures without ultrasound guidance.
Information on the administration and supportive data for various forms of local anesthesia is provided below in the setting of joint aspiration and injection and discussed in detail separately (see "Clinical use of topical anesthetics in children" and "Subcutaneous infiltration of local anesthetics"):
●Subcutaneous injection of lidocaine (most common) – The most common approach for local anesthesia during joint aspiration or injection is using a subcutaneous injection of lidocaine 1% without epinephrine at the site of needle entry and along the anticipated needle track. We typically administer 2 to 5 mL of lidocaine, depending on the distance the needle must travel from the skin to the joint (and therefore the age and size of the patient). We use a smaller-gauge needle (eg, 25- to 30-gauge) and choose the length based on the depth of the affected joint (typically 1.5 to 2.5 inches). However, for deeper joints we use a longer, larger-bore (eg, 23- to 25-gauge) needle to reach the appropriate depth and avoid the needle bending or breaking. (See "Subcutaneous infiltration of local anesthetics", section on 'Lidocaine'.)
Subcutaneous lidocaine offers rapid onset of anesthesia after a short period of a burning sensation. Many clinicians use "buffered lidocaine" (ie, lidocaine buffered with sodium bicarbonate), which neutralizes the acidity, thus decreasing the burning sensation [38,39].
As discussed above, we do not mix intraarticular glucocorticoids with lidocaine when doing intraarticular injections in pediatrics. (See 'Avoidance of mixing with local anesthetic' above.)
●Needle-free delivery of lidocaine – There are several needle-free delivery systems for lidocaine, including jet injection (ie, a "J-tip") and iontophoresis (ie, the use of electric currents to drive lidocaine into the skin). Several studies on venipuncture have shown that the jet injection system can reduce procedural pain for children [40,41]. While this system is not painful, we warn patients that it is loud and may startle them. By contrast, iontophoresis is used less often as it can cause burns, is painful, and has a slower onset of action and shallower penetration [12]. (See "Clinical use of topical anesthetics in children", section on 'Needle-free lidocaine delivery' and "Clinical use of topical anesthetics in children", section on 'Lidocaine iontophoresis'.)
●Ethyl chloride spray – Ethyl chloride spray is also commonly used to "freeze" the area of intended needle insertion prior to injection [42]. It can be used together with some other forms of local anesthetic (eg, injectable lidocaine). (See "Clinical use of topical anesthetics in children", section on 'Vapocoolant spray'.)
●EMLA cream – Eutectic mixture of local anesthetics (EMLA) cream (a combination of topical lidocaine 2.5% and prilocaine 2.5%) can be applied topically 30 to 60 minutes before a procedure to decrease the pain of the needle stick. In a randomized trial of 31 children, EMLA was found to be no more effective than placebo for preventing injection site pain [43]. However, despite this finding, some clinicians feel that the placebo effect is helpful [44]. (See "Clinical use of topical anesthetics in children", section on 'Lidocaine-prilocaine'.)
Of note, adequate local anesthesia is important even when patients are sedated for the procedure; an exception is when patients are under general anesthesia.
Site marking and sterilization — After confirming patient identifiers and the laterality for the procedure, we mark the intended procedure site by gently impressing the skin with a hard object (eg, the end of a ballpoint pen with the writing tip retracted, the sterile end of a needle sheath). This allows the mark to remain visible after the subsequent skin preparation.
To sterilize the procedure site, we typically use chlorhexidine or povidone-iodine. Chlorhexidine may be superior to povidone-iodine in preventing skin contamination of the aspirated fluid, based on data from adults who had skin sterilization prior to drawing blood cultures [45]. Of note, needle-free lidocaine delivery systems and EMLA cream are applied and wiped away prior to sterilization, while subcutaneous lidocaine injections and ethyl chloride spray are used after.
During the procedure, most pediatric providers use a sterile technique to minimize the risk of iatrogenic infection, including sterile gloves, drapes, and, if needed, a probe cover for ultrasonography [46]. An alternative approach that is commonly used in adults is a "no-touch" technique, where the provider does not touch the field after sterilization and can therefore use nonsterile gloves. (See "Joint aspiration and injection in adults: Indications and technique", section on 'No-touch technique'.)
More information on standard precautions to prevent infection during injections is discussed separately. (See "Infection control in the outpatient setting", section on 'Safe injection practices' and "Infection prevention: Precautions for preventing transmission of infection", section on 'Standard precautions'.)
Anatomic approaches to specific joints — The provider performing the procedure should have a thorough knowledge of the anatomy of the joint and surrounding structures, such as important blood vessels and nerves that must be avoided. The general principles of choosing an aspiration site in children are the same as those in adults, including optimizing the trajectory to minimize tissue damage and bony obstruction as well as avoiding neurovascular bundles and overlying soft tissue abnormalities (eg, cellulitis, psoriatic plaques). (See "Joint aspiration and injection in adults: Indications and technique", section on 'General principles'.)
The patient positioning, key landmarks, and needle insertion for specific joints in children is similar to that used for adults; this information is provided in detail elsewhere, with important caveats in pediatric patients noted below:
●Sternoclavicular joint – Aspiration and injection of the sternoclavicular joint in children is rare and is typically done with image guidance. (See "Joint aspiration and injection in adults: Indications and technique", section on 'Sternoclavicular joint'.)
●Shoulder (glenohumeral joint) – (See "Joint aspiration and injection in adults: Indications and technique", section on 'Shoulder'.)
●Elbow (ulnohumeral joint) – (See "Joint aspiration and injection in adults: Indications and technique", section on 'Elbow (ulnohumeral joint)'.)
●Wrist – The wrist contains three noncommunicating joint compartments, specifically the distal radioulnar, radiocarpal, and midcarpal joints. In addition, it can be challenging to distinguish arthritis and tenosynovitis of the wrist on physical examination. Ultrasound guidance may therefore be helpful when injecting a wrist joint. (See "Joint aspiration and injection in adults: Indications and technique", section on 'Wrist (distal radioulnar joint)'.)
●Carpometacarpal joint – (See "Joint aspiration and injection in adults: Indications and technique", section on 'Carpometacarpal'.)
●Other finger joints – (See "Joint aspiration and injection in adults: Indications and technique", section on 'Finger'.)
●Hip (femoro-acetabular joint) – Hip aspiration or injection in children is typically done with image guidance by a pediatric rheumatologist or interventional radiologist. (See "Joint aspiration and injection in adults: Indications and technique", section on 'Hip'.)
●Knee (patellofemoral joint) – The most commonly used approach for knee injection and aspiration in children is the medial parapatellar approach; in contrast to the approach outlined in adults, we maintain the knee straight rather than flexed to prevent the effusion from migrating to the suprapatellar recess. An alternative approach when there is a large effusion is to use the lateral suprapatellar approach since this is typically where most of the effusion is located.
We typically use the suprapatellar (SP) approach, as opposed to the infrapatellar (IP) approach, in children for several reasons. Firstly, the fluid in the knee generally aggregates in the suprapatellar region, making it a natural choice for aspiration and injection. Secondly, given the high percentage of cartilage in the distal femur and proximal tibia, the IP approach may lead to inadvertent penetration of the cartilage, putting the patient at risk for cartilage defects, fissures, and delamination. However, the IP approach may be performed cautiously in patients who cannot tolerate the normal supine positions (eg, those with significant knee contractures).
●Ankle (tibiotalar joint) – (See "Joint aspiration and injection in adults: Indications and technique", section on 'Ankle (tibiotalar joint)'.)
●Jaw (temporomandibular joint [TMJ]) – Aspiration and injection of the TMJ is generally performed by an interventional radiologist, maxillofacial surgeon, or rheumatologist who has expertise in injecting this joint. Procedures are done with image guidance (ie, fluoroscopy or ultrasonography) given the potential difficulty accessing this small space. Important risks include damage to the facial nerve, which is very rare, and heterotopic bone formation, which affects approximately 14 percent of children who undergo glucocorticoid injection of the TMJ [47]. The treatment of TMJ arthritis in JIA and associated risks of therapy are discussed in detail separately. (See "Juvenile idiopathic arthritis: Immunizations and complications", section on 'Treatment and prognosis'.)
●Sacroiliac joint – Sacroiliac (SI) joint injections are typically done with image guidance. (See "Musculoskeletal ultrasonography: Guided injection, aspiration, and biopsy of joints and related structures", section on 'Sacroiliac joint'.)
Indications for using image guidance during procedures are discussed above. (See 'When to use image guidance' above.)
Joint aspiration — Once the procedure site is marked, anesthetized, and sterilized, we proceed with joint aspiration. We insert the needle bevel-up to make it easier to puncture the skin. Various aspects of joint aspiration are outlined below:
●Debulking effusions – The amount of fluid to aspirate depends on the indication and the size of the joint and effusion. For patients with large effusions, aspirating more fluid (ie, debulking) may improve their pain. However, we typically avoid debulking in very small children since this requires a larger-bore needle, which can predispose to leakage of medications with subsequent subcutaneous atrophy and skin hypopigmentation In adults, limited data suggest that debulking effusions may make intraarticular glucocorticoid injections more effective; however this has not been studied in children [48].
●Switching syringes – If we need to switch the syringe during the procedure (eg, to aspirate additional fluid or inject medications after aspiration), we grip the distal half of the needle hub with a sterile hemostat. We avoid gripping the proximal, round portion of the hub as this may deform the aperture and damage the connection between the needle and the syringe.
●Dry taps – If fluid cannot be aspirated, providers may need to try an alternative approach and/or add image guidance. The approach to dry taps in children is similar to that in adults, which is discussed in detail elsewhere. (See "Joint aspiration and injection in adults: Indications and technique", section on 'Dry taps'.)
●Preparing samples – Once the procedure is complete, we assemble synovial fluid samples for laboratory analysis. This typically requires the use of two tubes: one for cell count and differential (typically collected in an ethylenediaminetetraacetic acid [EDTA] or heparin tube to prevent clot formation that may interfere with the cell count) and one for Gram stain and culture (collected in a sterile tube). The collection and analysis of synovial fluid are discussed in greater detail separately. (See "Synovial fluid analysis", section on 'Handling specimens'.)
Joint injection — The steps in intraarticular glucocorticoid injection are as follows:
●Aspiration and gross inspection of synovial fluid – We always aspirate synovial fluid prior to injecting glucocorticoids, in order to confirm that the needle is in the correct space [49]. We visually inspect the synovial fluid for color and transparency; if there is any evidence of septic arthritis (ie, purulent or green fluid) or hemarthrosis (ie, significantly bloody fluid that does not clear), the patient requires further evaluation of the underlying cause and should not receive intraarticular glucocorticoids. The optimal amount of fluid to aspirate is described above. (See 'Joint aspiration' above.)
●Glucocorticoid injection – After aspirating fluid, we maintain the needle in the joint space by holding the distal half of the needle hub with a sterile hemostat, remove the syringe used to aspirate fluid, and replace it with the syringe containing the glucocorticoid.
Alternatively, "reciprocating syringes" can be used where two syringes, one for joint aspiration and one for medication injection, are attached to the same needle. Limited data in adults suggest that this approach is associated with shorter procedure time and less procedure-related pain [50]; however, reciprocating syringes are uncommonly used due to limited availability, added expense, and bulky design [51].
●Needle removal – Based on the author's experience, we flush the needle with a small volume of sterile saline before withdrawing it. This can ensure delivery of all the medication and prevent extravasation of glucocorticoid into the surrounding tissues, which may cause skin atrophy and depigmentation. This approach is not possible when injecting small joints that cannot accommodate any additional volume (ie, fingers and toes).
POSTPROCEDURE MANAGEMENT —
We typically advise patients to implement the following measures after joint aspiration and/or injection, which are based on our clinical experience:
●Temporary covering of the procedure site with a sterile bandage.
●Analgesia as needed with nonprescription pain medications, such as acetaminophen and/or a nonsteroidal antiinflammatory drug (NSAID), and cold therapy (eg, application of a cool pack to the affected area for 20 minutes). (See "Pain in children: Approach to pain assessment and overview of management principles", section on 'Nonopioid analgesics'.)
●Avoidance of excessive activity that stresses the affected joint for 24 to 48 hours after the procedure. Of note, data to support this practice in children are very limited, and outcomes after procedures for certain joints (eg, wrists or elbows) in adults appear similar regardless of the use of immobilization [52,53].
●Resumption of regular personal hygiene to keep the area clean, including regular bathing or showering.
If joint aspiration was performed due to a high suspicion for septic arthritis, we promptly administer empiric antibiotic therapy after aspiration and continue therapy until culture results are available. (See "Bacterial arthritis in infants and children: Treatment and outcome", section on 'Empiric parenteral therapy'.)
INTERPRETATION OF SYNOVIAL FLUID —
Certain characteristics (eg, color, clarity, viscosity) and laboratory studies (eg, cell count and differential) of synovial fluid can give the clinician clues about the etiology of arthritis, as summarized in the table (table 2) as well as below and discussed in detail elsewhere (see "Synovial fluid analysis"):
●Noninflammatory fluid – Causes of noninflammatory joint effusions in children include trauma and overuse injuries, hypermobility disorders such as Ehler-Danlos syndrome, degenerative joint disease such as osteochondritis dissecans, avascular necrosis, and, rarely, Charcot arthropathy. Normal synovial fluid is clear or pale yellow, viscous, and usually has less than 200 white blood cells (WBC)/mm3 with <25 percent polymorphonuclear neutrophils (PMNs).
●Inflammatory fluid – More common causes of inflammatory synovial fluid in children include bacterial arthritis and inflammatory arthritis. In inflammatory arthritis, synovial fluid is usually yellow and viscous. The WBC count can range from 2000/mm3 to as high as 75,000/mm3 and typically has a neutrophilic predominance. In septic arthritis, synovial fluid is usually opaque and may be green, with variable viscosity. It can have upwards of 300,000 WBC/mm3, at least 75 percent of which are PMNs. Synovial fluid glucose levels decrease in the setting of infection and are usually <50 percent of serum glucose [54]. (See "Bacterial arthritis: Clinical features and diagnosis in infants and children", section on 'Synovial fluid interpretation'.)
●Bloody fluid – Grossly bloody fluid most often suggests trauma, bleeding diatheses, or neoplasms (eg, tenosynovial giant cell tumor [TGCT], formerly known as pigmented villonodular synovitis [PVNS]). When interpreting the WBC of grossly bloody fluid, some providers adjust according to how many WBC are expected per red blood cell (RBC; with a RBC:WBC ratio of approximately 500 to 1000:1). (See "Overview of hemarthrosis", section on 'Synovial fluid analysis and other laboratory findings'.)
It is important to note that in the presence of clinical signs and symptoms of septic arthritis, a normal synovial fluid cell count and/or a negative Gram stain are insufficient to exclude the possibility of bacterial infection. (See "Bacterial arthritis: Clinical features and diagnosis in infants and children", section on 'Synovial fluid interpretation'.)
COMPLICATIONS —
Complications due to joint aspiration or injections in children are infrequent and rarely serious [55]; they may include infection, bleeding, damage to nearby structures, and glucocorticoid-related adverse effects (eg, postinjection inflammatory reaction, facial flushing, skin atrophy and depigmentation).
Infection — Iatrogenic septic joint after joint aspiration or injection is rare, with only case reports in children [13]. In adult patients, the rate of iatrogenic infection after joint aspiration and/or injection is between 0.001 and 0.0003 percent [56]. (See "Joint aspiration and injection in adults: Complications", section on 'Septic arthritis'.)
Preventive steps to avoid this complication include using aseptic technique and avoiding injection in higher risk scenarios (eg, bacteremia, overlying tissue infection). (See 'Site marking and sterilization' above and 'Contraindications' above.)
Hemorrhage — Patients may bleed following joint aspiration or injection, as is the case with any invasive procedure. Hemarthrosis following joint aspiration or injection are rare. Certain measures may lower this risk for patients who have a tendency to bleed. (See 'Patients with an increased risk of bleeding' above.)
Damage to nearby structures — As with any procedure, there may be damage to surrounding structures when inserting the needle. We minimize the risk of damage by carefully selecting the procedural approach and, when appropriate, using image guidance. (See 'When to use image guidance' above and 'Anatomic approaches to specific joints' above.)
Glucocorticoid-associated toxicity — Intraarticular glucocorticoids may cause certain systemic effects, including transient adrenal suppression and facial flushing. In addition, there is a risk of developing adverse effects from glucocorticoids locally at the injection site, including a postinjection inflammatory reaction and subcutaneous atrophy and depigmentation.
●Systemic effects – Intraarticular glucocorticoids are absorbed systemically to some degree. While this phenomenon may be beneficial for some patients (ie, patients with widespread arthritis who experience improvement in joints that were not injected) [7,8], it can also cause a range of adverse effects typically seen with systemically administered glucocorticoids. In particular, facial and body flushing, emotional lability, menstrual irregularity, sleep disturbance, increased appetite, weight gain, and acne have been reported after intraarticular glucocorticoid injections [57,58]. Patients may develop a neutrophilic leukocytosis and, in those with diabetes, several days of relative hyperglycemia that require adjustment of therapy. In addition, transient suppression of endogenous cortisol has been reported in both adults and children following intraarticular glucocorticoid injection [59,60], as well as Cushing syndrome in patients with juvenile idiopathic arthritis (JIA) who receive intraarticular triamcinolone acetonide or triamcinolone hexacetonide [28,61]. (See "Joint aspiration and injection in adults: Complications", section on 'Facial flushing' and "Joint aspiration and injection in adults: Complications", section on 'Systemic effects'.)
Systemic side effects, particularly adrenal suppression, are more common after intraarticular injection with triamcinolone acetonide or betamethasone compared with triamcinolone hexacetonide [61] due to the relatively higher solubility and resultant peak plasma levels [62,63]. There is a direct relationship between peak plasma glucocorticoid levels and endogenous hydrocortisone suppression [23].
●Postinjection inflammatory reaction – Uncommonly, patients may develop a postinjection inflammatory reaction, which manifests as acute pain, swelling, and redness of the injected joint. There is significant overlap in the clinical manifestations of postinjection inflammatory reaction and iatrogenic septic arthritis; however, the former typically starts and spontaneously resolves within 48 hours of the injection, while the latter usually manifests more than 48 hours after the injection and does not improve without antibiotic therapy. Postinjection inflammatory reactions are thought to be caused by the formation of glucocorticoid crystals that irritate the synovium [64]. Such reactions rarely affect children [65-67]. (See "Joint aspiration and injection in adults: Complications", section on 'Postinjection flare'.)
If there is a concern for a postinjection inflammatory response, we treat with conservative measures (ie, acetaminophen and/or nonsteroidal antiinflammatory drugs [NSAIDs], cold therapy). In addition, if the onset of symptoms is >24 hours after the procedure, we perform a repeat joint aspiration to look for infection.
●Subcutaneous atrophy and depigmentation – Subcutaneous atrophy and depigmentation may occur at the injection site if the glucocorticoid leaks into the surrounding soft tissues [68], and may appear more prominent in patients with more pigmented skin. Such changes usually resolve over one to two years. The reported incidence of this complication varies from 1 to 8 percent of intraarticular glucocorticoid injections [67,69,70]. (See "Joint aspiration and injection in adults: Complications", section on 'Local skin or fat changes'.)
●Intraarticular calcifications – Imaging following intraarticular glucocorticoid injection often demonstrates calcifications located periarticularly or in the joint capsule [71-73]. Almost all patients are asymptomatic [67,71,72]. The pathogenesis of these calcifications is unclear.
Concerns have been raised about the effects of intraarticular glucocorticoids on growing articular cartilage; however, the limited available data do not suggest any long-term negative effects. In a study of 14 children with chronic arthritis who received intraarticular glucocorticoids, there was no evidence of cartilage deterioration or unexpected change in skeletal growth when comparing a baseline magnetic resonance imaging (MRI) of the affected joint to ones obtained seven weeks and 13 months after the procedure [74]. Similarly, a study of 30 children with JIA who received an intraarticular glucocorticoid injection in an affected knee did not find any evidence of cartilage damage on radiographs obtained one year after the injection [75].
SUMMARY AND RECOMMENDATIONS
●Appropriate use of joint aspiration and injection – Joint aspiration (ie, arthrocentesis) in children is used primarily to evaluate for infection and can also provide temporary relief from large effusions through decompression of the joint space. Intraarticular glucocorticoid injections are used in the management of many forms of inflammatory arthritis; however, they should not be given if there is a concern for an active infection affecting the area being injected (eg, septic arthritis, overlying cellulitis, bacteremia). (See 'Appropriate use of joint aspiration and injection' above.)
●Preprocedural management – Prior to arthrocentesis, we perform a comprehensive joint examination and patient history to help determine the anticipated procedural approach and the need for sedation and/or image guidance. (See 'Preprocedural management' above.)
•When to use procedural sedation – Although many children tolerate arthrocentesis with local anesthesia and appropriate reassurance in an outpatient setting, some may require procedural anxiolysis, moderate or deep sedation, or, rarely, general anesthesia. We typically offer options beyond local anesthesia for children when they are unable to tolerate an unsedated procedure due to an underlying neurologic or psychiatric disorder (eg, autism spectrum disorder, generalized anxiety disorder), have a prior negative experience with a nonsedated procedure, require multiple joint injections, and/or have low pain tolerance or limited ability to cooperate with the procedure. (See 'When to use procedural sedation' above.)
•When to use image guidance – Certain imaging modalities can guide accurate intraarticular needle placement. When indicated, we generally use ultrasonography rather than CT or fluoroscopy to avoid radiation exposure. In children requiring aspiration or injection of a joint that is difficult to access based solely on direct palpation of landmarks (eg, temporomandibular joint [TMJ], hip) or that has multiple noncommunicating joint spaces (eg, wrist, ankle), we suggest using ultrasound guidance (Grade 2C). We also use this approach for tenosynovial effusions and consider it for other scenarios when a trained ultrasonographer is readily available. (See 'When to use image guidance' above.)
●Equipment and medications – Supplies for joint aspiration and/or injection are outlined in the table (table 1). (See 'Equipment and medications' above.)
•Needle and syringe size – The optimal needle gauge and length for joint aspiration and/or injection depends upon the size of the joint, the degree of the effusion, and patient body habitus. Joint aspiration requires a relatively larger-bore needle. (See 'Needle and syringe size' above.)
•Intraarticular glucocorticoids – When available, we use triamcinolone hexacetonide for intraarticular injections; otherwise, we use triamcinolone acetonide or, for small joints, methylprednisolone acetate. Dosing varies based on the child's age and weight, joint being injected, size of the medication vial, and provider experience. We do not mix glucocorticoids with a local anesthetic (eg, lidocaine). (See 'Intraarticular glucocorticoids' above.)
●Technique
•Local anesthesia – Options to administer local anesthesia vary based on local availability. We typically administer lidocaine at the anticipated procedure site via needle injection or, in the case of an ultrasound-guided injection without aspiration, jet injection (ie, a "J-tip"). (See 'Local anesthesia' above.)
•Site sterilization – During the procedure, most pediatric providers use a sterile technique to minimize the risk of iatrogenic infection. An alternative approach is a "no-touch" technique, where the provider does not touch the field after sterilization and can therefore use nonsterile gloves. (See 'Site marking and sterilization' above.)
•Anatomic approaches to specific joints – We optimize the needle trajectory to minimize tissue damage and bony obstruction, and we avoid neurovascular bundles and overlying soft tissue abnormalities (eg, cellulitis, psoriatic plaques). (See 'Anatomic approaches to specific joints' above.)
•Joint aspiration – Once the procedure site is marked, anesthetized, and sterilized, we insert the needle bevel-up and aspirate fluid. Only a small amount is required for synovial fluid studies; however, aspirating additional fluid from larger joints may help relieve pressure and subsequent pain. (See 'Joint aspiration' above.)
•Joint injection – We always aspirate synovial fluid prior to injecting glucocorticoids to confirm correct needle placement and grossly inspect fluid. We do not inject glucocorticoids if there is any evidence of septic arthritis (ie, purulent or green fluid) or hemarthrosis (ie, significantly bloody fluid that does not clear). (See 'Joint injection' above.)
After aspirating fluid, we maintain the needle in the joint space, remove the syringe used to aspirate fluid, and replace it with the syringe containing the glucocorticoid. After injecting the glucocorticoid, we flush the needle with a small volume of sterile saline before withdrawing it.
●Complications – Complications in children are infrequent and rarely serious; they may include infection, bleeding, damage to nearby structures, and glucocorticoid-related adverse effects (eg, skin atrophy and depigmentation). (See 'Complications' above.)
ACKNOWLEDGMENT —
The UpToDate editorial staff acknowledges Thomas JA Lehman, MD, who contributed to earlier versions of this topic review.
