Accurate intra-articular knee joint injection in the obese? ’Fat Chance!’—A clinical lesson and recommendations for secondary referral

Figures & data

Figure 1. Postoperative photograph of both knees (anterior view), illustrating the large cavity following surgical incision, drainage and debridement of the abscess secondary to corticosteroid knee joint injection.

Figure 2. Illustration depicting the anterolateral entry point for knee injections; with the knee in 90 degrees of flexion, the needle entry point (just above ‘A’) should be in the palpable soft spot between the patella, lateral femoral condyle and proximal tibia (Gerdy's tubercle).

Table I. For primary care providers: when NOT to inject.

In severe osteoarthritis, injection by specialists may result in more successful intra-articular placement (19,20). For any patient for whom joint replacement may be required in the near future (21). In rheumatoid patients who received immunosuppressive therapy in the past year (22). We further suggest that this high-risk group should include any immunocompromised or diabetic patients. In technically difficult cases, such as in obesity as in the illustration (Figure 1), we suggest referral to specialists in secondary care who are skilled in achieving intra-articular needle placement via various anatomical approaches, frequently perform more complex injections and have access to US-guidance (23).

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