Rethinking Viscosupplementation: Ultrasound- Versus Landmark-Guided Injection for Knee Osteoarthritis

Objectives: Viscosupplementation, intra-articular injection of hyaluronic acid (HA), for knee osteoarthritis has fallen somewhat out of favor, with studies failing to show consistent benefits in pain reduction. Hyaluronic acid must enter the joint space to be beneficial; however, landmark-guided injection can be substantially inaccurate, especially in obese patients. We aimed to determine whether ultrasound (US) guidance to ensure needle placement for HA knee injection resulted in improved outcomes as reflected by surgery-free survival compared to landmark-guided HA knee injection.

Methods: All community-dwelling patients in 6 contiguous surrounding counties receiving HA knee injection either by landmark guidance (n = 647) or by US guidance (n = 500) were analyzed for the degree of arthritis, body mass index, follow-up injection, and subsequent need for knee arthroplasty. A subgroup analysis of obese patients was also performed.

Results: The US- and landmark-guided HA injection cohorts were similar with respect to sex, body mass index, and the degree of arthritis. Of 1147 patients receiving knee HA injection, 462 subsequently underwent knee arthroplasty. Significantly fewer patients in the US-guided HA injection cohort went to surgery (33.2%) compared to the landmark-guided cohort (45.8%; P < .001). The subgroup analysis for obese patients showed even larger differences (34.8% versus 51.8%; P < .001).

Conclusions: Knee osteoarthritis treatment by viscosupplementation can be optimized by US guidance, ensuring intra-articular needle placement. Using an objective surgical outcome, our study shows that rethinking viscosupplementation to ensure intra-articular delivery improves effectiveness. Patients receiving US-guided knee HA injection were significantly less likely to undergo subsequent knee arthroplasty than patients receiving landmark-guided HA injection.