# Comparative Outcomes of Delayed i-PRF Combination with Nanofracture in the Treatment of Large Chondral Defects in the Knee

## TL;DR

Injecting i-PRF three weeks after nanofracture surgery improves knee cartilage repair and pain relief in patients with large cartilage defects.

## Contribution

Demonstrates that delayed i-PRF injection enhances cartilage repair outcomes after nanofracture in large knee defects.

## Key findings

- Group 1 showed significantly better WOMAC scores at final follow-up compared to the control group.
- MRI evaluations showed significantly improved cartilage repair in the i-PRF group (MOCART 2.0 score: 57.1 vs. 50).
- No significant differences were found in IKDC, Tegner scores, or time to return to daily activities between groups.

## Abstract

Background and Objectives: This study aimed to evaluate whether delayed intra-articular application of injectable platelet-rich fibrin (i-PRF) improves clinical and radiologic outcomes compared to nanofracture alone. Materials and Methods: A total of 76 patients with ICRS Grade III–IV femoral condyle or trochlear cartilage defects larger than 2 cm2 were enrolled in this prospective controlled study. Patients were allocated into two groups: Group 1 (n = 40) underwent nanofracture followed by delayed intra-articular i-PRF injection at three weeks postoperatively, while Group 2 (n = 36) underwent nanofracture alone. Preoperative MRI was evaluated using the AMADEUS grading system. Clinical outcomes—including WOMAC and IKDC scores—were assessed at baseline and at 6, 12, and 24 months postoperatively. MOCART 2.0 scoring was used to evaluate cartilage repair at ≥12 months follow-up. Results: Both groups demonstrated significant functional improvement according to the IKDC and WOMAC scores. However, Group 1 showed a significantly greater improvement in WOMAC total score at final follow-up (Group 1: 20.1 ± 4.3 vs. control: 23.2 ± 3.4; p = 0.0008). No statistically significant differences were found between groups in IKDC score (p = 0.238), Tegner score (p = 0.776), or time to return to daily activities (p = 0.401). Baseline demographic, radiological, and intraoperative variables were comparable between groups (p > 0.05 for all). Radiologic outcomes based on the mean MOCART 2.0 scores were 57.1 and 50, respectively, in group 1 and group 2 (p = 0.0316). These results showed significantly improved results in group 1 according to the MRI evaluation. Conclusions: In patients with large chondral defects (>2 cm2), delayed intra-articular i-PRF injection following nanofracture may improve mid-term functional and radiological outcomes, particularly in pain and symptom relief. This regenerative strategy enhances cartilage repair potential during the early healing phase without adding surgical complexity.