Genicular Artery Embolization for the Treatment of Symptomatic Knee Osteoarthritis

Abstract

Genicular artery embolization (GAE) is a novel therapy to treat patients with symptomatic knee osteoarthritis (OA) by reducing synovial arterial hypervascularity. This study evaluates the safety and efficacy of GAE for the treatment of symptomatic knee OA.

Methods: A prospective, single-center, open-label U.S. Food and Drug Administration-approved investigational device exemption study was conducted. Patients enrolled in the study were 40 to 80 years old, with moderate or severe knee OA (Kellgren-Lawrence grade 2, 3, or 4), who previously had failure of conservative therapy. Baseline pain (visual analog scale [VAS]) and symptom scores (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]) were assessed. After femoral arterial access was achieved, GAE of 1, 2, or 3 genicular arteries supplying the location of the subject's pain, as determined by digital subtraction angiography and cone-beam computed tomography, was performed using 100-μm particles. Adverse events and symptoms scores were assessed at 1 week, 1 month, 3 months, 6 months, and 1 year after GAE.

Results: Over a 10-month period, 40 subjects were enrolled. The median age was 69 years (range, 49 to 80 years). The median body mass index was 29 kg/m² (range, 19 to 44 kg/m²). Knee OA severity was grade 2 in 18% of the patients, grade 3 in 43%, and grade 4 in 40%. Technical success was achieved in 100% of the subjects. Transient skin discoloration and transient mild knee pain after the procedure were common and expected. Treatment-related adverse events included a groin hematoma requiring overnight observation in 1 subject, self-resolving focal skin ulceration in 7 subjects, and an asymptomatic small bone infarct on magnetic resonance imaging at 3 months in 2 subjects. The WOMAC total and VAS pain scores decreased by 61% and 67% at 12 months from a median baseline of 52 (of 96) and 8 (of 10), respectively. Twenty-seven patients (68%) had a reduction of ≥50% in both WOMAC total and VAS pain scores.

Conclusions: This prospective trial demonstrates that GAE is effective and durable in reducing pain symptoms from moderate or severe knee OA that is refractory to other conservative therapy, with an acceptable safety profile.

Level of evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Fig. 1

CONSORT (Consolidated Standards of Reporting Trials) flow diagram.

Fig. 2-A

Fig. 2-A Knee radiograph showing joint-space narrowing of the medial compartment, consistent with Kellgren-Lawrence grade-3 OA.

Fig. 2-B

Fig. 2-B Access was obtained in the right femoral artery with a 3-French sheath.

Fig. 2-C

Fig. 2-C Angiogram of the distal superficial femoral artery with a radiopaque marker placed at the site of the pain, showing hypervascularity along the medial joint space.

Fig. 2-D

Fig. 2-D Rotational 3D reconstructed angiogram identifies the descending genicular artery as coursing toward the region of pain.

Fig. 2-E

Fig. 2-E Selective catheterization and digital subtraction angiogram of the descending genicular artery confirms the presence of hyperemia in the medial joint space.

Fig. 2-F

Fig. 2-F After embolization with Embozene microspheres, a postembolization angiogram shows vessel patency with the absence of hyperemia.

Fig. 3

Mean WOMAC total scores over time. The I-bars indicate the upper and lower limits of the 95% confidence interval (CI), which were calculated with formula: 95% CI = the mean ± 1.96 × standard error of the mean.

Fig. 4

Univariate analysis. An odds ratio (OR) of >1 favors clinical success (defined as ≥50% reduction in WOMAC at 12 months).