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

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.

Keywords: AMADEUS; MOCART 2.0; bone marrow stimulation; cartilage regeneration; chondral defect; injectable PRF; nanofracture.

Figure 1

Arthroscopic images of a Grade IV chondral lesion located on the femoral trochlea of a 42-year-old male patient presenting with chronic anterior knee pain. A ring curette was used to debride unstable cartilage in order to create stable vertical margins. (B) The surface after the calcified cartilage layer has been removed. (A,C) nanofracture awl was used to induce controlled perforations that allowed access to the subchondral bone marrow. (D) Successful subchondral access and marrow stimulation are confirmed by the visible effusion of marrow elements from nanofracture sites.

Figure 2

The WOMAC total scores for both treatment groups pre- and postoperative at 6th 12th and 24th months. Although both groups showed improvement after surgery, Group 1 (i-PRF + nanofracture) consistently had lower (better) WOMAC scores, particularly at 12 and 24 months.

Figure 3

The IKDC scores obtained preoperatively and at 1, 6, 12, and 24 months are shown in the graphical abstract.