Single Injection Reduces Pain in Severe Knee Arthritis Patients

85% of Patients Avoided Knee Replacement at One Year

This Croatian study followed 20 patients with severe knee osteoarthritis who received a single injection of their own processed fat tissue. All patients had advanced disease—80% had the most severe grade (Kellgren-Lawrence grade IV). After one year, 17 of 20 patients (85%) had improved enough to avoid total knee replacement surgery. Only three patients (15%) went on to have their knees replaced during the study period.

Pain Scores Dropped by More Than Half

Patients experienced substantial pain relief across all measures used in the study. The visual analog scale (a simple pain rating) decreased by 54% to 82% from baseline. The WOMAC score, which measures pain, stiffness, and physical function, improved by 40% to 45%. These improvements were statistically significant, meaning they were unlikely to occur by chance.

• Pain during daily activities decreased substantially

• Stiffness improved noticeably

• Physical function scores showed meaningful gains

Processed Fat Contains Multiple Healing Cell Types

Researchers analyzed what was actually in the injected material. They found three main cell types that may contribute to healing:

• Pericytes (helper cells that support blood vessel repair)

• Endothelial progenitor cells (cells that help form new blood vessels)

• Adipose stromal cells (supportive cells from fat tissue)

These cells work together through natural signaling processes. They may help reduce inflammation and support tissue repair in the damaged joint.

Knee Function Improved Significantly Across All Measures

The KOOS score (Knee Injury and Osteoarthritis Outcome Score) improved dramatically—between 46% and 176% compared to baseline measurements. This score evaluates five areas: pain, other symptoms, activities of daily living, sports and recreation, and quality of life. All improvements were statistically significant with P values less than 0.001.

What This Means for Patients With Severe Arthritis

This study is notable because it focused on patients with late-stage disease. Most regenerative treatments are tested on mild or moderate arthritis. These patients had severe cartilage damage and were typically considered candidates for knee replacement.

The procedure itself is minimally invasive. Fat tissue is harvested from the patient's own body, processed using the Lipogems® system to create micro-fragmented adipose tissue, and then injected into the knee joint. Because the tissue comes from your own body (autologous), there is minimal risk of rejection or allergic reaction.

Important Limitations to Consider

This was a small study with only 20 patients and no control group for comparison. Without a placebo group, researchers cannot rule out that some improvement came from the placebo effect or natural disease fluctuation. The 12-month follow-up period also limits our understanding of long-term benefits.

However, the researchers note this is among the first studies to show positive effects specifically in patients with late-stage knee osteoarthritis. For patients facing joint replacement surgery, this treatment may offer an option to delay or potentially avoid that major procedure.

Source: Hudetz et al., Croatian Medical Journal, 2019.