Nine things you need to know about joint injection

1. Know which conditions are most likely to respond to injection

Indications for injections include arthritis, bursitis, tendinopathy and tenosynovitis, enthesopathy, neuromas, entrapment and impingement syndrome.¹ Although pain relief is the most common indication for injection, there are other potential benefits, e.g. neuropathic symptoms in carpal tunnel syndrome.

2. There are contraindications to injection

These include local skin infection and systemic infection where the patient is unwell, allergy, active rash (e.g. eczema or psoriasis) or broken skin at the site of injection, uncontrolled coagulopathy, fracture or unstable joint, tendons that are high risk of rupture (e.g. Achilles tendon) and injection into a prosthetic joint.

3. It’s essential that patients give informed consent

Ensure that patients are informed of the potential risks of injection. This should be documented clearly in the notes.² It is good practice to give the patient information about the risks and benefits of injection and time to consider these. Providing this in a leaflet can help patients to absorb the information given.

Risks include infection, tendon rupture, tendon atrophy, nodule formation, skin hypopigmentation, lipoatrophy, post injection flare of symptoms, flushing, menstrual irregularities and elevated blood sugar levels in diabetic patients.³ Although the consequence of infection can be very serious, it’s a rare complication. Studies have quoted risks from 1:3000 to 1:50000.¹ The use of aseptic technique during the procedure can help reduce this risk.

4. The content of the injection can vary

Hydrocortisone acetate, methylprednisolone and triamcinolone acetonide are common steroids used for joint and soft tissue injections in the UK. Triamcinolone is the least soluble and theoretically lasting longer at the injection site, giving rise to a longer therapeutic action.^1,4 Before injection, the steroid is frequently diluted with equal volume of anaesthetic. The immediate analgesic effects may help confirm the placement and potentially increase the spread of steroid.⁴

Anaesthetics commonly used are lidocaine and bupivacaine. Lidocaine acts faster (within 2-5 minutes of injection) with the effects lasing up to two hours. On the other hand, bupivacaine has a slower onset of action (5-10 minutes) but its effects lasts longer for up to 4-8 hours.⁴ There is no clear evidence in the literature on the optimum dose and frequency of steroid injections, however, there is evidence that steroid injections too soon before joint replacement may increase infection risk.⁵ Therefore, consider not performing an injection within the three months prior to a patient’s planned surgery.

5. Anticoagulation doesn’t need to stop but take into account the timing of the dose

For patients on warfarin, ensure that recent INR levels are below 4.5. Evidence suggests that risk of significant haemorrhage is very low below this level.⁶ Many patients are currently taking DOACs and information from DOAC manufacturers suggests that anticoagulation need not be interrupted when performing an injection. These agents have a shorter half-life than warfarin, and consideration should be given to not performing injections during peak drug activity, e.g. 2-4 hours after last dose of rivaroxaban.

6. Do not inject into tendons

When injecting for tendinopathy, inject around the tendon, either in the tendon sheath or around the tendon sheath. Do not perform an intratendinous injection. Be slow and gentle to keep the pressure of injection low when injecting into the tendon sheath to reduce risk of avascular necrosis of the tendon.

7. Evidence of therapeutic benefit is not always strong in some conditions

The use of corticosteroid injections to treat lateral epicondylitis is increasingly discouraged⁷, as increasing evidence shows high recurrence rate and limited long-term benefits of steroid injection. It has short-term benefits in terms of pain relief and this window of opportunity can be used for physiotherapy exercises, which will improve the condition in the long run.⁸ Similarly, in impingement syndrome and adhesive capsulitis, the role of injection is to provide pain relief in order to aid physiotherapy exercises, which is crucial to the recovery process.

8. Joint injections can be used as a diagnostic tool

When there is an overlap of conditions that could potentially cause pain in an anatomical area, a diagnostic injection can exclude one or the other condition. For example, injection into the subacromial space can help differentiate subacromial impingement from adhesive capsulitis or glenohumeral joint osteoarthritis.

9. Patients must be provided with aftercare instructions

The Resuscitation Council UK website states that cardiopulmonary arrest can occur between two minutes and 20 minutes of an injection. Therefore, consider asking the patient to remain at site 20 minutes after the injection. It is also advisable to ask patients to avoid strenuous activity for two weeks post-injection since the risk of tendon rupture may be increased in that time. Explain immediate aftercare instructions to the patient and longer term rehab instructions, including exercises and activity modification specific to the condition being treated. An aftercare instruction leaflet is a useful aid memoire for the patient.

Dr Jean Wong is a GPSI in sports and musculoskeletal medicine in Loughborough and an RCGP sports and exercise medicine rep.

Dr. Sukhman Kalra is a GPSI in musculoskeletal medicine at the Telford Musculoskeletal Service (TEMS) and GP principal at Rothwell and Desborough Healthcare Group.

The Primary Care Rheumatology Society runs a joint injection workshop in their annual conference in November, which can be useful for refreshing knowledge of regional joint anatomy.

References

Douglas L. Joint and Soft Tissue Injections. MDDUS. October 2014
https://www.mddus.com/resources/publications-library/fyi/issue-08/informed-consent. Accessed August 2018
Aleem AW, Syed UAM, Nicholson T, et al. Blood Glucose Levels in Diabetic Patients Following Corticosteroid Injections into the Subacromial Space of the Shoulder. Archives of Bone and Joint Surgery. 2017;5(5):315-321.
https://now.aapmr.org/steroids-and-corticosteroids/. Accessed August 2014
Marsland D, Mumith A, Barlow IW. Systematic Review : the safety of intraarticular corticosteroid injection prior to total knee arthroplasty. Knee. 2014 Jan;21(1):6-11. doi: 10.1016/j.knee.2013.07.003. Epub 2013 Aug 12
Douketis JD. Pharmacologic properties of the new oral anticoagulants: a clinician-oriented review with a focus on perioperative management. Curr Pharm Des 2010;16(31):3436-41.
Coombes BK, Bisset B, Brooks P, Khan A, Vicenzino B. Effect of Corticosteriod Injection, physiotherapy, or Both on Clinial Outcomes in Patients with Unilateral Lateral Epicondylalgia. A randomized Controlled Trial. JAMA. 2013;309(5):461-469. doi:10.1001/jama.2013.129
Olaussen M, Hlmedal O, Lindbaek M, Brage S, Solvang H. Treating lateral epicondylitis with corticosteroid injections or non-electrotherapeutical physiotherapy: A systematic review.