Description
Purpose: To evaluate the clinical and MRI results of nanofat injection in patients with knee arthrosis (OA). The hypothesis of the study was that injection of nanofat close to Hoffa´s fat pad relieves pain, decreases functional disability and delays development of intraarticular degenerative changes.
Material: 10 patients (5 male, 5 female); mean age 48.9 years (range 30 - 61) were included in the study.
Patients with Kellgren grade 2 - 3 knee OA, who had not responded to intraarticular injections of PRP, hyaluronic acid and cortisone together with a physiotherapy program during three months were included in the study. 9 of 10 had undergone arthroscopic surgery previously. All patients were on the waiting list for total knee arthroplasty.
Methods: The intraarticular nanofat injections were done under arthroscopic visualization close to the Hoffa’s fat pad. The knee was immobilized after the injection with a compression bandage in the straight position for 3 days. Clinical evaluation was performed using VAS, Oxford and KOOS scoring systems at inclusion 3, 6, 12 months after nanofat injection. MRI was performed in 8 patients and evaluated using the Osteoarthritis Score (MOAKS), before and 12 months after injection.
Results: Significant improvements compared with the preoperative findings were found in VAS (p= 0.002), KOOS symptoms (p=0.008) and KOOS pain (p=0.038) scores after 6 months. At 12 months no further improvements were found. No significant improvements over time were found in terms of range of motion and isokinetic strength in extension for the treated knee.MRI revealed increase in the size of cartilage damage area in 1 of 8 patients, bone marrow edema was increased in 3 of 8 and decreased in 2 of 8, synovial effusion was increased in 2 of 8 and decreased in 2 of 8 patient and Hoffa’s fat pad edema was increased in 2 of 8 and decreased in 2 of 8 patients. No complications related to the injection were registered.
Conclusion: Intraarticular nanofat injection close to Hoffa’s fat pad significantly improves pain at 6 and 12 months, without complications. In most patients no increase in intraarticular degenerative findings were found on MRI. It appears that the procedure can delay total knee arthroplasty in some patients.
