Since NPs and PAs have historically played a prominent role with intraarticular joint injections and may perform even more of these procedures in the future, this author intertwines key principles, pertinent pearls and an informative case study to help facilitate improved results.

Intraarticular injections are a safe and effective modality for painful, swollen joints due to a “flare” of osteoarthritis, inflammatory arthritis or gout.1 Injections are also useful in improving impaired mobility due to joint pain and swelling.2 Additionally, researchers of one randomized study have found that intraarticular injections of hyaluronic acid (Hyalgan) or viscosupplementation are more effective than Naprosyn for managing joint pain from osteoarthritis of the knee.3

While many believe intraarticular injections are primarily performed by physicians, nurse practitioners (NPs) and physician assistants (PAs) have been administering this type of treatment as part of routine office procedures for decades.

Given the emerging trends in rheumatology practice, this practice may become even more common for knee and shoulder injections. As Jane Denay, BSN, MSN, CFNP, pointed out in a lecture at the American College of Rheumatology (ACR) conference, there is a critical shortage of rheumatologists in the United States.4 It is anticipated that this shortfall will only get worse with the aging of the population and an expected increase in the number of people with rheumatologic diseases. One solution, as stated by the ACR and the Association of Rheumatology Health Professionals (ARHP), is an increased emphasis on collaborative practices between rheumatologists, NPs and PAs, which could produce more accessible, high quality care for these patients.4

Here is the anterior approach to the “Dry-Tap” intraarticular injection of the knee.

The literature is sparse when it comes to supporting or disputing the roles of NPs and PAs in performing joint injections. However, literature in the United Kingdom has assessed the role of nurses in performing corticosteroid injections for patients with rheumatologic disorders.5,6 The nurses had attended a five- to six-month training program for joint injections. When researchers surveyed the patients, the patients felt that the nurses delivered safe and effective injections. A subsequent audit by the researchers of the study confirmed that the nurses performed the majority of the injections at the facility and that their standards were at least as good as the standards of the physicians.5,6

Indeed, joint arthrocentesis and injection allow practitioners to help patients receive timely, efficient care and pain management. Timely administration of these procedures may also facilitate referrals for further rheumatologic and or surgical evaluation as needed.

Reviewing The Indications For Intraarticular Injections
In order to provide safe, efficient care for patients who are in need of an intraarticular injection, it is important to be aware of the diagnostic and therapeutic indications for such procedures. Therapeutic indications of joint arthrocentesis and intraarticular injection include:

• decompression of a painful and tense effusion;
• facilitating range of motion after the draining of a painful hemarthrosis; and
• administration of a potent antiinflammatory such as a corticosteroid.

Diagnostic indications include ruling out infection, crystal-induced effusion, hemarthrosis and providing an overall diagnosis during the initial evaluation.7

In my experience, I found that a combined corticosteroid and lidocaine method of injection is an efficient method of providing an antiinflammatory bolus to a patient in pain. In order to assess a patient’s pain level, one may utilize a visual analog scale (VAS). Assessing pain levels before and after with the VAS enables clinicians to assess the effectiveness of the injection.

Absolute contraindications for corticosteroid injections include an infected joint, a history of allergies or anaphylaxis, and joint prosthesis. Relative contraindications include hypercoagulapathy states, minimal relief from two previous injections, uncontrolled diabetes and an inaccessible joint.8

A Primer On Corticosteroid Injections
When inflammation in a joint occurs, there is an immune process causing a proliferation of leukocytes. With increased blood flow, there is a transport of polymorphnuclear leukocytes, macrophages and plasma proteins to the joint. There is an interruption of arteriolar blood flow, which results in hypoxia. All of the above result in a painful, swollen joint.9

Accordingly, the purpose of performing a corticosteroid injection to a joint is to apply an antiinflammatory mechanism. After the injection, there are: alterations in chemotaxis and function; increased viscosity of synovial fluid; stabilization of cellular lysosomal membranes; alterations in hyaluronic acid production; alterations of synovial permeability; and changes in synovial fluid leukocyte count and activity.8

Injectable corticosteroid solutions are described as short, intermediate and long-acting solutions. In our institution, we use intermediate acting solutions. The solutions are further defined in terms of solubility. The duration of effect is inversely related to solubility. The less soluble the agent, the longer it remains in the joint, thereby providing a longer effect.

One can see the preparation for a subacromial injection into the right shoulder as the clinician cleans the area with iodine solution.

The shorter acting solutions are less irritating and typically cause less of a “post-injection” flare than the intermediate and long-acting solutions. One would typically administer the short-acting solutions in smaller joints.

Potential systemic side effects of steroid injections include flushing of the skin, menstrual irregularities, muscle wasting and myopathy (chronic use), impaired glucose tolerance (unlikely), osteoporosis, psychological upset, steroid arthropathy and adrenal suppression. Local side effects may include subcutaneous atrophy, skin depigmentation and tendon rupture. Another local side effect is infection but this is reportedly very rare, occurring once out of every 10,000 injections.

In order to avoid or reduce the risks of possible side effects, clinicians should consider the following guidelines. The maximum amount of fluid allowed per joint is 10 cc for the shoulder (although one should limit this to no greater than 3 cc in the subacromial bursa) and knee, 5 cc for the elbow and hip, 3cc for the ankle, 2 cc for the wrist, 1.5 cc for the toes and 1 cc for the thumb and fingers.

In regard to intermediate acting corticosteroids, Depo-Medrol (methyl prednisone acetate) has intermediate potency and duration. Approximate dosing per joint for this agent ranges from 40 to 80 mg for the shoulder and knee; 10 to 40 mg for the wrist, ankle and elbow; and 5 to 10 mg for the PIP joints of the fingers and toes. Kenalog (triamcinolone acetonide) has intermediate potency and duration. For this agent, approximate dosing per joint is 2 to 10 mg for small joints and 10 to 80 mg for large joints.

As for the needle size, one should employ a 18 to 22-gauge needle for knee and shoulder injections; a 22 to 25-gauge needle for wrist, ankle and elbow injections; and a 25 to 30-gauge needle for injections of the fingers and interphalangeal joints.

How To Inform The Patient And Obtain Consent
It is helpful to have a standard protocol to review with patients prior to performing any intraarticular injection or arthrocentesis. Clinicians should obtain verbal and written consent. When explaining the injection procedure to patients, I will tell them that the purpose of a steroid injection is to give them an immediate bolus of an antiinflammatory. I compare the injection to taking Motrin but I let patients know the injection is much more effective and provides quicker relief. It is also helpful to let patients know that injections have very little systemic effects.

Before clinicians can administer the corticosteroid injection, it is important to be absolutely sure the patient does not have an infection. Accordingly, I explain to the patient that I need to take some fluid out of his or her knee to check for the possibility of infection (see “A Guide To Synovial Fluid Analysis” on page 24). If the knee does not appear infected, I tell the patient I can proceed to give him or her the corticosteroid injection, which will include a lidocaine or anesthetic solution that will help the patient with immediate pain relief.

I explain to the patient that he or she may have more pain tomorrow and the day after, and then the steroid solution will begin to work over the next week or two. Clinicians should let patients know that some people have an inflammatory reaction that will respond well to ice and Tylenol or antiinflammatories. I also advise patients to rest for a few days and ice the injected knee. Then they can gradually increase their activity as tolerated but they should avoid knee bending, twisting and squatting for three to five days. I tell these patients to avoid vigorous sports for a month.

We also let patients know that if the injection has no impact in six weeks, we can try a second injection. However, we try to limit injections to every three months or three or four times per year. We try not to inject more than that due to a possible theoretical risk of articular surface damage. However, there is currently no study to support this theory.

In fact, there is one randomized double-blind study that evaluated the safety and efficacy of long-term, intraarticular corticosteroid injections for knee osteoarthritis.10 Using the medication triamcinolone, the authors of the study reported significant reductions in pain and no long-term intraarticular cartilage damage. One may also give the patient an ACR “fact sheet” on these injections.11

Case Study: When A Patient Presents With Two Weeks Of Knee Pain
Ensuring a thorough patient history and physical is critical prior to considering a joint injection. Recently, a 57-year-old male hiker presented with right knee pain and swelling. He has had the pain for two weeks after a long hike. He says it is painful to climb the stairs and also experiences pain with prolonged sitting. The patient is an engineer who works at a desk all day and has very stiff knees by the end of the day. He believes he has a history of arthritis but is not sure. He did have a prior sports-related injury to the knee and notes that “some cartilage” was removed.

The patient did not complain of any “catching” or “locking” in the knee. He says there is some morning stiffness but it does not last longer than 30 minutes. The patient has no fever, chills, constitutional or systemic complaints, or nighttime pain. There is no unexplained weight loss or fatigue. There are no insect bites or tick exposure. The patient has no significant past medical history. There is no history of cancer or bleeding disorders. The patient is married and notes no history or present complaints of sexually transmitted disease. There is no family history of knee problems.

This type of subacromial injection is the most common approach and safest to the subacromial space.

Aside from medications for his knee pain, the patient is not currently taking any other medications. In regard to the knee pain, the patient is has taken one 200 mg tablet of Motrin a day for two weeks with no side effects. He says he has iced his knee a couple of times but he is not sure what to do now.

During the physical examination, the patient walks with a non-antalgic gait. He has patellofemoral pain but no joint line pain. His lower limb alignment reveals genus varus. With the patient in a sitting position, I can assess for any pain coming from the lumbar spine. One can also check for patellofemoral crepitation and motor strength. When the patient is lying down, one can assess for an effusion. Clinicians may also check for the presence of a ballotable patella, cellulitis, skin rash, abrasions, bursa swelling or clinical signs of infection.
One should proceed to check active and passive range of motion (ROM). After a patient relaxes and demonstrates full unrestricted ROM with passive ROM, the etiology of pain is most likely extraarticular.

Clinicians should then check for ligamentous stability or meniscus involvement with McMurray’s maneuver. Proceed to perform a complete musculoskeletal review, assessing for any active synovitis, skin rash and strength testing. Also assess for any atrophy, particularly atrophy of the quadriceps muscles including the vastus medialis oblique (VMO).

This patient has a small effusion to his right knee. He lacks full extension in his knee by 5 degrees, and full flexion to 160 degrees. There is no evidence of warmth, cellulitis or lymphadenopathy. Weightbearing plain X-rays reveal moderate degenerative joint disease (DJD). While the DJD affects all three compartments of the knee, it appears to be worse in the medial compartment and the patellofemoral joints.

At this point, the findings, which include a history of remote injury to his knee, reveal pain that is getting worse and effusion with overuse activity. While there are no clinical signs of an infection in the knee of this patient, I feel an aspiration is needed to confirm this.

I proceed to discuss the possibility of a joint injection with the patient. I do note that it is possible to treat his DJD with conservative treatments including corticosteroid injections, physical therapy, NSAIDs, offloading braces for his malalignment issues and possible orthotics with a lateral wedge. However, before we can proceed with a therapeutic joint injection, we need to rule out a possible infection in the knee.

Pearls For Using Aspiration To Assess For Infection
In our institution, we use two different types of medium-acting or intermediate to long-acting corticosteroid solutions. They are Depo-Medrol (methyl prednisone acetate) 40 mg/cc and Kenalog (triamcinolone acetonide) 40 mg/cc.

When it comes to corticosteroid injections, it is best to have the patient lying down or in a sitting position. For the case study patient, we attempted a supine approach to the lateral border of the knee. While this is a safe and effective approach, it may be difficult in this case given this patient’s degree of patellofemoral DJD.
First, I anesthetize the subcutaneous tissue/skin by using a 25-gauge needle with 1 to 2 cc of 1 percent lidocaine without epinephrine. One would insert the needle about 2 cm proximal and lateral to the superior lateral border of the patella. Proceed to spray the skin with methyl chloride. I prefer to have the knee flexed about 20 degrees. Using a rolled towel or gown can facilitate this.

I use two separate syringes for the anesthethia and the corticosteroid. You need to find the anatomical markings before applying the local anesthethia. Find the anatomical landmarks by locating the lateral superior border of the patella. At about 2 cm and a 45 degree angle, insert the needle into the lateral retinaculm of the patellofemoral joint. If one encounters bony resistance of the patella, pull back and redirect the bevel of the needle until you feel a slight popping sensation. This is the feel of the needle entering the joint/synovial capsule.

Holding some vacuum pressure on the needle allows clinicians to aspirate any synovial fluid for analysis. Additionally, one will need to pull back on the syringe to assess for placement and to ensure there is no puncturing of a blood vessel. I obtain a yellow colored aspirate of approximately 12 ccs from the patient. There is no evidence of purulence or foul odor. The fluid is non-cloudy and has some viscosity to it. I am now confident there is no infection.

At this point, one can hold the test tube against typed text. If you can see the text without difficulty, this connotes “clear fluid” in regard to the degree of clarity of synovial fluid and whether there is a concern of infection or not.

How To Ensure The Success Of Corticosteroid Injections
After determining that the patient did not have an infection, I can proceed to the therapeutic corticosteroid injection. Using a sterile technique with a sterile Kelly clamp, I proceed to inject a mixture of 1 percent lidocaine and 1 cc of Depo-Medrol into the knee. One should proceed to cleanse the area with alcohol and then cover the injection area with a band-aid and ace wrap.

I ask the patient to ice the area with an ice pack at least four times a day for the next few days. This is usually effective for swelling management. One may also have the patient take Tylenol ES bid or an NSAID. While I encourage the patient to begin gentle isometric quadriceps strengthening exercises, I ask him to avoid kneeling, squatting, deep knee bends and stair climbing for three to five days. I also ask the patient to avoid hiking for another month and encourage a follow-up visit in two weeks. I also order an offloading brace for this patient in order to support the degree of DJD medial compartment involvement. The patient also could benefit from a lateral wedge foot orthotic for the aforementioned malalignment issues.

Two days after the procedure, the patient complains of increased pain. Yet he has no redness in the knee, cellulitis or fever. However, the longer acting corticosteroids can create a “crystal synovitis” approximately 24 hours after the injection.1 Knowing this, I emphasize icing and antiinflammatory treatment. I tell the patient we can also try a short course of a narcotic analgesic if necessary.

At the two-week follow-up appointment, the patient notes he is feeling great. While he can proceed with cycling and swimming at this time, I still have him restrict activity at the gym and avoid stair climbing and hiking.

During subsequent follow-up appointments for this patient, clinicians may consider discussing viscosupplementation as an adjunct to his treatment plan. In small clinical studies, researchers have shown that viscosupplementation decreases joint pain, improves viscoelasticity and decreases inflammation. Some studies have shown effectiveness of up to six months to a year. Clinicians can administer viscosupplementation safely as it has little known side effects. In order to use this modality, there must be documented OA changes on plain radiographs. In regard to viscosupplementation, focal skin reactions can occur. In order to minimize this effect, clinicians can emphasize icing after injections and activity limitations for three weeks.

Shoulder Injections: What You Should Know
When it comes to performing shoulder injections of the glenohumeral joint, one can safely perform these either anteriorly or posteriorly. However, posterior injections are preferred due to a safer approach and ease of injection.

With the posterior approach to the shoulder joint, one should internally rotate the humeral head. Then proceed to find the bony landmarks. Palpate the very distal aspect of the acromion place one finger breath below this site and make a mark with a depressed pen or nail marker. After applying local anesthesia and methyl chloride spray, use the aseptic technique. Utilizing a 22 gauge, 1.5-in. needle, insert the bolus of 1 cc of methyl prednisone and 2 cc of 1 percent lidocaine without epinephrine. One should direct the injection medially and posteriorly. If you encounter bony resistance or any resistance, pull back and reattempt the injection.

One clinical pearl is trying some very gentle pendulum swings immediately following the injection and applying ice for five to 10 minutes. This allows one to monitor the effect of the injection and reassess the patient’s reaction. Five minutes after the injection, I reexamine the patient’s pain with a VAS scale and also reexamine his or her active and passive range of motion.

In Conclusion
Given the changing demographics in the country as well as emerging trends among health care providers in the rheumatology arena, it is more than likely that nurse practitioners and physician assistants will play a larger role in administering intraarticular injections for patients with rheumatologic disorders. By having a strong grasp of the key principles and an awareness of the issues that may arise with these injections, clinicians should be able to provide timely and effective injections for those with musculoskeletal complaints in a confident and collaborative manner.

When one performs a “Dry Tap” knee intraarticular injection superior lateral, one may feel a slight “pop” sensation as the needle enters the area.