Preliminary Report on the Time‐Related Effect of a Single Autologous Adipose‐Derived Mesenchymal Stem Cells Injection in Hip Osteoarthritis: A Retrospective Observational Study

<b>Background:</b> Recently, intra-articular injection of mesenchymal stem cells (MSCs) had been proposed as a conservative treatment for hip osteoarthritis (HOA). Adipose tissue was demonstrated as a viable source of MSCs because of the high concentration of cells and the easy access to the donor site. The purpose of this study was to evaluate the time-related results of a single intra-articular injection of autologous adipose-derived stem cells (aASCs) in a series of patients with HOA. <b>Methods:</b> A retrospective study was conducted on 30 patients with HOA, who underwent an intra-articular injection of aASCs between September 2018 and January 2021. Inclusion criteria for the procedure were as follows: onset of symptoms of the affected hip in the prior six or more months ago, failure of the conservative treatment (NSAIDs and/or physiotherapy) and age > 18 years. Exclusion criteria were trauma in the affected hip occurred in the previous 3 months, recent arthroscopic treatment, infectious joint disease, chondromatosis of the hip or any other secondary HOA, malignancy, hyaluronic acid or other injections in the previous 6 months and incomplete follow-up. Because a low BMI makes extremely difficult to harvest enough adipose tissue, patients with a BMI < 18 were also excluded. The Oxford Hip Score, the 12-item Short Form Survey and Visual Analogue Scale were used to evaluate the results of the proposed treatment at regular intervals. <b>Results:</b> In 27/30 patients, a constant improvement in pain relief, hip function and quality of life was observed during the entire follow-up period of 12 months. Two patients underwent a subsequent total hip arthroplasty. <b>Conclusion:</b> The single injection of aAMSCs seems to be a valuable treatment for HOA. A constant amelioration of pain and function could be observed in most patients at 12 months of follow-up.