89 - Genicular Artery Caliber in Patients with Chronic Pain after Knee Arthroplasty: An Age-Matched Case-Control Study

Over 1 million knee replacements are performed each year with approximately 20% of these patients experiencing chronic post-knee replacement pain (CPKRP) {1}. While genicular artery embolization (GAE) is being used to treat the neovascularity and hyperemia in painful knee osteoarthritis, less is known about GAE and vascular changes in patients with CPKRP {2,3,4}. This study aimed to evaluate genicular artery caliber in a CPKRP cohort as compared to knee replacement subjects with no chronic pain (NCP).

Materials and Methods:

A retrospective review of lower extremity computed tomography angiograms (CTA) was performed between January 2024 and August 2024. Utilizing double orthogonal measurements, the diameter, circumference, and cross-sectional area of the descending genicular artery (DGA) origin and adjacent superficial femoral artery (SFA) were measured. Superior medial (SMGA) and superior lateral genicular artery (SLGA) diameters were measured. Measurements were performed independently by two readers and intraclass correlation coefficients (ICC) were obtained. Body mass index (BMI) and number of days between arthroplasty and CTA were recorded. Comparison was made using paired t-tests.

Results:

Twenty-two patients were identified (11 with CPKRP and 11 age-sex matched subjects without chronic pain). Mean age in the CPKRP and NCP were 64 (53-73) and 67 years (64-78), respectively. 8/11 patients in each cohort were female (73%). Patients with chronic pain exhibited relatively larger DGA diameters (p< 0.01), circumferences (p< 0.01), and areas (p< 0.05) when controlling for SFA diameter, circumference, and area, respectively. No significant differences were found for the SMGA or SLGA measurements, for BMI, or for days between surgery and CTA. ICCs for DGA and SFA measurements were excellent (0.92, 0.91), moderate for the SLGA (0.59) and poor for the SMGA (0.28). 

Conclusion:

These findings suggest that patients with chronic refractory post-knee replacement pain have relatively enlarged DGAs as compared to age-sex matched patients without chronic knee pain. This data suggests that chronic genicular artery changes may be occurring in CPKRP, warranting further investigation into angiogenesis and neovascularity in CPKRP, as well the potential utility of GAE for this challenging population.