Patients with stage II of the knee osteoarthritis most likely benefit from the intra-articular injections of autologous adipose tissue—from 2 years of follow-up studies
Authors: Bąkowski Paweł , Kaszyński Jakub , Baka Cezary , Kaczmarek Tomasz , Ciemniewska-Gorzela Kinga , Bąkowska-Żywicka Kamilla , Piontek Tomasz 
Published: June 2021

Abstract
Background
Knee osteoarthritis (OA) is a common, chronic, progressive and degenerative disease which affects patients’ quality of life and may cause disability and social isolation. OA is a huge economic burden for the patient and a large strain for the whole healthcare system. Articular cartilage has a small potential to repair, with progressively more clinicians emphasizing cellular therapy. Subcutaneous fat tissue in human body is a large reservoir of mesenchymal stem cells (MSCs) and is been harvested in minimally invasive, simple procedure. The purpose of this study was to define a specific group of patients with knee osteoarthritis, who are the most likely to benefit from the treatment with intra-articular injection of an autologous adipose tissue (AAT).

Methods
From 2016 to 2018, 59 symptomatic bilateral and unilateral knee OA patients were treated with a single intra-articular (IA) injection of an autologous adipose tissue (AAT). Before the treatment and at the follow-up, the participant was asked to fulfill the Knee Injury and Osteoarthritis Outcome Score (KOOS), the International Knee Documentation Committee 2000 (IKDC 2000), The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Health Questionnaire EQ-5D-5L and to quantify the pain in the affected joint with a Numeric Rating Scale (NRS). Moreover, the patients were asked to: (i) assess their satisfaction with the effects of the conducted treatment: from 0 (unsatisfied) to 10 (very satisfied), (ii) describe the rehabilitation, if it was performed (supervised or individual and duration in weeks) and (iii) indicate any additional treatment applied, like IA injections of hyaluronic acid (HA) or platelet-rich plasma (PRP), knee arthroscopy, partial or total knee arthroplasty (TKA) at the follow-up.

Results
The mean age of 37 participants (16 males and 21 females) included into statistical analysis was 57.78 ± 7.39 years, the mean BMI was 31.30 ± 7.51. The questionnaires were fulfilled after the average follow-up time of 27 ± 6.5 months. A significant difference (p < 0.05) compared with the baseline, was observed in pain [NRS], WOMAC, KOOS index, pain, symptoms, ADL, Sport and Rec, QoL, EQ-5D-5L index. The satisfaction in the whole group was 6.16 ± 3.07. There was no significant difference between satisfied and unsatisfied patients in BMI and pain [NRS] at the baseline. 6 out of 7 patients with stage IV in K-L were unsatisfied with the effects of the treatment with AAT.

Discussion
The main conclusion of this study is that the patients with stage II of the knee OA with normal BMI are were most likely to benefit from IA injection of AAT, in contrast to the patients with stage IV, who will not beware not satisfied with the effectiveness of this kind of treatment. There were no adverse events reported at the donor site as well as in the treated knee joints.