Objectives

Knee osteoarthritis (OA) is a debilitating joint disorder affecting tens of millions of people worldwide. Nonoperative treatment options have variable efficacy and none stop or reverse the progression of OA. Furthermore, there is a lack of literature supporting the efficacy of intra-articular corticosteroids, one of the most common treatment options. The purpose of this study is to evaluate pain relief and functional improvement after knee OA treatment with a novel therapeutic intervention, microfragmented adipose tissue, in comparison to a saline placebo and gold-standard corticosteroid injections.

Methods

Patients with radiographic knee OA, a minimum pain score of 3 on the visual analog scale (VAS), and no prior knee injection were eligible for inclusion. Patients were randomized to one of three treatment groups: microfragmented adipose tissue (MFAT), corticosteroid (CS), or saline placebo (P) injection. Both the practitioner and patient were blinded to the injection in the CS and P groups. A sham liposuction procedure was not performed. For the MFAT group, both an orthopaedic surgeon and plastic surgeon performed the lipoaspiration portion together under local anesthesia. The VAS pain scale, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Knee Injury and Osteoarthritis Outcome Score scale (KOOS) were recorded pre-procedure and at specified time points post-procedure up to one year.

Results

A total of 62 patients have been enrolled (92% follow-up), with a study goal of 75 total patients to achieve power. Patients were randomized to: MFAT = 22, CS = 21, P = 19. A preliminary analysis of these 62 patients was completed to compare post-procedure outcomes to pre-procedure pain and functionality. The WOMAC score improved in the MFAT group by a mean of 30 points at 1 year follow-up, compared to 10 in the CS and 11 in the P groups (p = 0.01). The KOOS pain score improved in the MFAT group by a mean 32 points at 1 year follow-up, compared to 8 in the CS and 11 in the P groups (p=0.03). VAS scores improved across all groups with average changes: MFAT 3.4, CS 1.5, P 1.4 (p = 0.14). When a linear mixed effects model was used to quantify changes in outcomes over the 1 year post-procedure period, the MFAT group demonstrated a consistently positive improvement across all five outcomes measures, whereas no consistent trend was noted in the P group and a negative trend was noted in the CS group after the initial 2 week improvement. Patients with more severe radiographic knee OA had poorer outcome scores in all groups. No complications were noted in any of the study patients with the exception of mild expected donor site morbidity of minor pain and ecchymosis in the MFAT group.

Conclusions

Nonoperative knee OA treatment options are limited with variable efficacy. It is critical to evaluate patient outcomes rigorously prior to instituting novel procedures or treatments. Preliminary data show the microfragmented adipose tissue injection group demonstrated consistently the largest improvement in outcome scores at 6-12 month follow-up compared with the placebo and corticosteroid groups.