Long-term effects of infrapatellar fat pad SVF infiltration in knee osteoarthritis management: A prospective cohort study

Background

Knee osteoarthritis (OA) is a prevalent and debilitating condition that significantly impacts patients' quality of life and poses a substantial socioeconomic burden. Current treatments, including nonsteroidal anti-inflammatory drugs (NSAIDs) and physical therapy, often provide only temporary relief and fail to halt disease progression, particularly in advanced stages where knee replacement surgery becomes the primary option. Regenerative cell therapies, particularly those utilizing mesenchymal stem cells (MSCs), have emerged as promising alternatives due to their anti-inflammatory and regenerative properties. This study investigates the efficacy of stromal vascular fraction (SVF) derived from autologous adipose tissue when injected into the infrapatellar (Hoffa's) fat pad, an approach that leverages the rich vascular and stem cell environment of the fat pad to potentially modulate inflammation and promote tissue repair.

Methods

Patients receiving therapy with SVF were invited to participate in the study. Inclusion criteria encompassed male and female patients aged 18 years or older with a Kellgren-Lawrence score up to 4, while exclusion criteria included malignant tumors, sepsis, or skin lesions at the site of collection or injection. A total of 25 patients were included in the study cohort, with two patients receiving bilateral treatment, resulting in 27 knees analyzed.

For the correlation analysis, an additional four patients who had only completed the six-month follow-up were included, one of whom underwent bilateral treatment. This extended the correlation analysis cohort to 29 patients and 32 knees. However, these four patients were excluded from the final study analysis as they had not completed the two-year follow-up. Consequently, the final analysis focused exclusively on the 25 patients (27 knees) who completed the full two-year follow-up.

Results

Significant improvements were observed in VAS pain scores and KOOS subscales for pain, activities of daily living (ADL), and quality of life (QOL) at 6 and 24 months (p < 0.05). The correlation between the number of injected cells and functional improvements was significant for ADL at 6 months (Spearman's rho = 0.31, p = 0.044). This time point was prioritized to evaluate early therapeutic responses, as it represents a critical window when cellular activity and therapeutic effects are believed to peak. Focusing on the six-month follow-up allowed for a detailed assessment of these early impacts while minimizing potential confounding factors observed in later stages. No major complications were reported.

Conclusion

SVF infiltration into the infrapatellar fat pad shows promising long-term benefits in pain relief and functional improvement for knee OA patients. Despite the lack of blinding and a control group, these findings suggest that SVF therapy could be a viable minimally invasive alternative to more invasive surgical interventions.