Fluoroscopy Confirms Effective Distribution of Hyaluronic Acid from Ultrasound-Guided Knee Injection: Study

"Future research should investigate whether the volume of injectate present in the tibiofemoral joint correlates with patient outcomes," the researchers wrote in Interventional Pain Medicine.

Viscosupplement injections are a widely used treatment for knee osteoarthritis. However, there is limited understanding of how the injected material disperses within the knee joint after the procedure. To fill this knowledge gap, Caroline Varlotta, Department of Rehabilitation and Human Performance, Mount Sinai Hospital, New York, NY, USA, and colleagues aimed to evaluate, using ultrasound and fluoroscopy, whether the injectate administered into the suprapatellar recess effectively disperses into the tibiofemoral joint.

For this purpose, the researchers conducted a descriptive case series and a reliability test-retest study at an outpatient rehabilitation center within an academic teaching hospital. The study involved 14 adults, aged 44 to 80, with knee osteoarthritis classified as grade 2-4 on the Kellgren and Lawrence scale, all of whom were candidates for hyaluronic acid injections.

Participants received ultrasound-guided knee injections of hyaluronic acid combined with contrast into the suprapatellar recess. After the injections, fluoroscopic images were taken to visualize the initial distribution of the injectate. The participants followed a walking protocol, after which additional fluoroscopic images were captured to assess how the injectate dispersed.

The main outcomes measured included determining whether the injectate introduced into the suprapatellar recess was localized to the tibiofemoral joint following the walking test. Additionally, the study assessed the interrater agreement among two radiologists and one interventional physiatrist regarding the location of the injectate.

The following were the key findings of the study:

• Injectate placed in the suprapatellar recess using an ultrasound-guided technique will disperse to a varying extent from the suprapatellar recess into the tibiofemoral or patellofemoral joint after a brief bout of walking.
• Images of US-guided knee injections identified by an experienced interventionalist to represent correct needle placement and injectate location, confirmed by reference-standard fluoroscopy, can be corroborated by a blinded radiologist and are, therefore, reliable.

The prospective case series reveals that injectate administered into the suprapatellar recess disperses into the tibiofemoral and patellofemoral joints. The accuracy of this observation was confirmed using ultrasound and fluoroscopic imaging, with inter-rater reliability demonstrated through agreement among two radiologists and one interventional physiatrist.

"Future research should explore additional factors that may influence dispersion, such as the severity of osteoarthritis, the viscosity of the injectate, and the precise location of the injection," the researchers concluded.

Reference:

Varlotta, Caroline, et al. "Accuracy of Ultrasound-guided Knee Injections Confirmed By Fluoroscopy." Interventional Pain Medicine, vol. 2, no. 1, 2023, p. 100174.