Corticosteroid Injections for Osteoarthritis

Corticosteroids, also known as glucocorticoids, mimic cortisol – a hormone naturally produced by the adrenal glands to regulate stress and inflammation [7]. When injected intra-articularly, they bind to cytoplasmic receptors in synovial cells and chondrocytes, translocating to the nucleus to suppress inflammatory gene transcription. This multifaceted action inhibits phospholipase A2, reducing arachidonic acid metabolites, including prostaglandins and leukotrienes that drive pain and swelling [8][9].

These medications excel where oral non-steroidal anti-inflammatory drugs (NSAIDs) fail – gastrointestinal intolerance, renal impairment, or cardiovascular contraindications limit systemic therapy for many osteoarthritis patients. 

This is because intra-articular (IA) corticosteroids deliver the drug directly to the inflamed joint, achieving higher local bioavailability than systemic administration. This reduces the dose needed and limits side effects like GI or CV risks associated with oral NSAIDs. Studies confirm IA routes provide superior synovial fluid levels with <10% systemic circulation [10].

This targeted delivery means injections are delivered by specialists using evidence-based guidance. Superficial targets include anatomical landmarks – bone prominences, joint lines, muscle bellies. Deeper structures benefit from ultrasound guidance, where precision delivery is considered even more accurate [11][12].

Considering Corticosteroid Injections’ Indications and Suitability 

Specifically, corticosteroid injections treat mild-to-moderate osteoarthritis across weight-bearing and upper limb joints, plus related tendinopathies including lateral epicondylitis (tennis elbow), plantar fasciitis, patellar tendinopathy, shoulder/hip/knee tendinopathy, and Achilles tendinopathy [13] [14].

Optimal candidates exhibit persistent pain despite optimised oral/topical therapy, joint effusion limiting physiotherapy progress, symptom flares blocking sleep, work, or caregiving, or NSAID contraindications such as GI bleed history, renal impairment, or heart failure [15][16].

NICE guidelines (UK’s gold-standard recommendations) endorse intra-articular corticosteroid injections precisely for these scenarios – when oral treatments fail, prove unsuitable, or cause side effects [16]. This is because they offer reliable pain relief across the knee, hip, hand and other joints, empowering individuals to re-engage with essential physiotherapy and restore function.

In this way, injections prove strategic within stepped-care pathways: first-line paracetamol/exercise, second-line topical NSAIDs/physiotherapy, third-line injections bridging to viscosupplementation, bracing, or surgical evaluation. 

Examining the Clinical Evidence and Outcomes For Corticosteroid Injections

Studies and systematic reviews provide robust evidence for corticosteroid injections in osteoarthritis management.  For example, a landmark analysis of 27 randomised controlled trials involving 2,267 patients demonstrated that intra-articular knee injections reduced pain by 2.0 points on a 10-point visual analogue scale at one month compared to placebo, with a number-needed-to-treat of just 5 for clinically meaningful improvement [17].

This efficacy extends across multiple joints. Shoulder injections improve range of motion by 25-35 degrees within two weeks, while hip injections reduce WOMAC pain scores by 28% at three months. Pain reduction manifests rapidly; 50-70% improvement emerges within 72 hours, peaking at 70-85% by week two. Functional gains follow closely; timed up-and-go tests improve by 2.5 seconds and 6-minute walk distances increase by 35 metres [9].

Trials combining injections with structured exercise demonstrate 40% greater functional gains versus exercise alone, as reduced pain enables higher training intensity and better compliance. Sleep disturbance resolves among 75% within one week, enhancing work capacity and caregiving ability [9][17].

This efficacy comes at the same time as proven safety. Controlled trials show no accelerated cartilage damage, with complication rates under 1% when using ultrasound guidance (>95% accuracy vs 70-85% blind). At the same time, systemic effects remain minimal compared to oral steroids, making injections ideal for NSAID-intolerant patients [18].