Regenerative cell therapies have emerged in recent years as promising treatments for numerous musculoskeletal conditions, including OA. This study showed that the administration of MAT to patients with early-stage hip OA can relieve pain and provide functional improvement without causing any complications or side effects. Overall, participants reported that they were satisfied with the MAT procedure for hip OA, and in our study, we found a reduction in the amount of analgesic drug used by patients at the 3rd month of follow-up compared to the preprocedure.
MSCs were first discovered in adipose tissue in 2001 and have since been recognized as a viable cell source for regenerative medicine [13]. In studies carried out in the following years, it was reported that MSCs showed both anti-inflammatory and chondroprotective activities [14]. Although the number of studies on the ADSC procedure, especially in the treatment of knee OA, has increased in recent years, most studies in the literature have inconsistent protocols and formulations of ADSC, and this is the most important factor that makes it difficult to compare results between studies. The use of unexpanded versus expanded cells is one of the major discrepancies in research. The former allows for a heterogeneous cell suspension in the form of SVF or microoil, which may be used in a one-step technique, while the latter relates to ADSC in vitro culture, which produces more homogeneous cells. However, this method necessitates a two-step process. Although SVF showed poorer regeneration at first (4 weeks of follow-up) than ADSC cultured in a pilot trial of a focal osteochondral lesion in a goat knee without OA, SVF tended to show better regeneration later (4 months follow-up) [15]. This is due to the fact that the diverse cell population of the main effect of SVFs is to promote the microenvironment that allows regeneration rather than differentiation. However, more research is needed to identify the most accurate animal model and the most favorable cell model for treating OA.
Six patients with hip OA were treated with intraarticular injections of autologous ADSC, according to Dall'Oca et al. [16] patients had improved Harris hip score (67.2 vs 84.6, p < 0.001), WOMAC score (36.3 vs 19.8, p < 0.001), and VAS score mean values (4.6 vs 1.5, p < 0.001) at 6-month follow-up. In our study, we obtained similar results, although the patients had a shorter follow-up period.
Centeno et al. in 2006, conducted a study in which a patient with hip OA administered two injections of autologous bone marrow mononuclear cells into the hip joint within one month [17]. They reported partial neocortex regeneration on the surface of the hip joint on MRI images eight weeks after injections and reported that the patient's range of motion of the hip joint improved significantly. In a study published by Centeno et al. in 2014, they examined autologous bone marrow concentrate (BMAC) injections in hip OA and reported that the mean improvement of the Oxford Hip Score was 6.4 points (p < 0.001) at a mean follow-up of 4.9 months [18]. In a prospective cohort study published in 2018, 63% of 25 patients with early stage hip OA who received BMAC injections were satisfied at 6 months of follow-up after the procedure and reported a significant improvement in the WOMAC index [19]. Similar findings were observed in a study that followed patients with osteoarthritis of the hip, knee, and ankle for 30 months treated with bone marrow-derived mesenchymal stem cells (BM-MSC) [20]. However, the hip OA patients in this study comprised a small proportion of cases, making it difficult to generalize the findings to hip OA specifically. BM-MSCs are traditionally extracted from cancellous bone at the iliac crest, proximal tibia, proximal humerus, and calcaneal tuberosity. Concerns about the high cost of enzymatic processing, as well as senescence and loss of multipotency, have encouraged SVF derived from subcutaneous abdominal fat to be injected intraarticularly into idiopathic osteoarthritic knees in a clinical investigation that included 18 patients (ages 18 to 75) [21]. Articular cartilage regeneration was observed in the medial femoral and tibial condyles, as well as the lateral femoral and tibial condyles, as well as an increase in cartilage volume in the medial femoral and tibial condyles, according to an MRI examination. The primary distinction between SVF and microfat is that SVF is a suspension of various cell populations without tissue matrix (or only in a small quantity), whereas microfat is made up of purified and resized AT, which preserves the stem cell niche. Because direct comparative studies have not yet been conducted, the impact of this biological difference on clinical outcomes has not yet been confirmed. The use of collagenase enzymatic digestion is one of the production systems required to make SVF, which makes it more than "minimal manipulated cells" according to FDA criteria. Its usage is restricted in various countries throughout the world due to manipulation of its cell content for regulatory and ethical reasons [22].
Although no serious adverse reactions have been reported, fat-derived treatments also have the potential for adverse reactions, including inflammation and infection. n patients with knee osteoarthritis, Jo et al. [21] found a very low infection rate (0.002%) after intra-articular injection of autologous adipose tissue-derived MSC. Except for a few individuals who encountered minor localized adverse effects such as rash and erythema, Emadedin et al [23]. observed no significant side effects. In our research, there were no problems or adverse events in the abdomen where fat was harvested or the area of the hip where the injection was administered.
This study lacked placebo control due to its retrospective nature. Also, the sample size is small. The relationship between age, sex, and severity of OA and the procedure has not been clearly established. Furthermore, it does not include pre- and post-procedure MRI evaluation of patients or other scaling methods to measure cartilage regeneration after treatment.