Osteoarthritis is a leading cause of pain and disability across the world. With an aging population its prevalence is likely to further increase. Current accepted medical treatment strategies are aimed at symptom control rather than disease modification. Surgical options including joint replacement are not without possible significant complications. A growing interest in the area of regenerative medicine, led by an improved understanding of the role of mesenchymal stem cells in tissue homeostasis and repair, has seen recent focused efforts to explore the potential of stem cell therapies in the active management of symptomatic osteoarthritis. Encouragingly, results of pre-clinical and clinical trials have provided initial evidence of efficacy and indicated safety in the therapeutic use of mesenchymal stem cell therapies for the treatment of knee osteoarthritis. This paper explores the pathogenesis of osteoarthritis and how mesenchymal stem cells may play a role in future management strategies of this disabling condition.

Introduction The management of intra-articular chondral defects in the knee remains a challenge. Inadequate healing in areas of weight bearing leads to impairment in load transmission and these defects predispose to later development of osteoarthritis. Surgical management of full thickness chondral defects include arthroscopic microfracture and when appropriate autologous chondrocyte implantation. This latter method however is technically challenging, and may not offer significant improvement over microfracture. Preclinical and limited clinical trials have indicated the capacity of mesenchymal stem cells to influence chondral repair. The aim of this paper is to describe the methodology of a pilot randomised controlled trial comparing arthroscopic microfracture alone for isolated knee chondral defects versus arthroscopic microfracture combined with postoperative autologous adipose derived mesenchymal stem cell injections. Methods and analysis A pilot single-centre randomised controlled trial is proposed. 40 participants aged 18–50 years, with isolated femoral condyle chondral defects and awaiting planned arthroscopic microfracture will be randomly allocated to a control group (receiving no additional treatment) or treatment group (receiving postoperative adipose derived mesenchymal stem cell treatment). Primary outcome measures will include MRI assessment of cartilage volume and defects and the Knee Injury and Osteoarthritis Outcome Score. Secondary outcomes will include further MRI assessment of bone marrow lesions, bone area and T2 cartilage mapping, a 0–10 Numerical Pain Rating Scale, a Global Impression of Change score and a treatment satisfaction scale. Adverse events and cointerventions will be recorded. Initial outcome follow-up for publication of results will be at 12 months. Further annual follow-up to assess long-term differences between the two group will occur. Ethics and dissemination This trial has received prospective ethics approval through the Latrobe University Human Research Ethics Committee. Dissemination of outcome data is planned through both national and international conferences and formal publication in a peer-reviewed journal. Trial registration number Australia and New Zealand Clinical Trials Register (ANZCTR Trial ID: ACTRN12614000812695).

A prospective analysis of the effect of autologous adipose derived mesenchymal stem cell (MSC) therapy in the treatment of an osteochondral defect of the knee with early progressive osteoarthritis following unsuccessful surgical intervention of osteochondritis dissecans (OCD). After failed conventional management of OCD a patient undergoes intra-articular MSC therapy. Patient outcome measures included the Numeric Pain Rating Scale (NPRS), the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Structural outcome was assessed using MRI with the novel technique of T2 mapping used to indicate cartilage quality. Following MSC therapy the patient reported improvement in pain and function as measured by NPRS, WOMAC and KOOS. Repeat MRI analysis showed regeneration of cartilage. MRI T2 mapping indicated hyaline like cartilage regrowth. In this report, the use of MSCs, after unsuccessful conventional OCD management, resulted in structural, functional and pain improvement. These results highlight the need to further study the regenerative potential of MSC therapy. Australian and New Zealand Clinical Trial Registry Number - ACTRN12615000258550 (Date registered 19/03/2015 – retrospectively registered).

Objective: To evaluate the long-term safety and efficacy of adipose-derived mesenchymal stem cell (ADMSC) therapy in the treatment of knee osteoarthritis (OA). Methods: 329 participants with knee O... Plain language summary The aim of this study was to assess the benefit of stem cell therapy in the treatment of mild to severe knee osteoarthritis. A total of 329 study participants with painful kn...

To assess the safety and efficacy of an allogeneic adipose-derived mesenchymal stem cell preparation (MAG200) in the treatment of knee osteoarthritis over 12 months. A single-centre, double-blind, ascending dose, randomised controlled trial. 40 participants with moderate knee osteoarthritis were randomised to receive a single intra-articular injection of MAG200 (dose cohorts:10, 20, 50, 100 ​× ​10⁶ ​cells) or placebo. Primary objectives were safety and efficacy according to a compound responder analysis of minimal clinically important difference in pain (numerical pain rating scale [NPRS]) and function (Knee Injury and Osteoarthritis Outcome Score - Function in Daily Living subscale [KOOS_ADL]) at month 12. Secondary efficacy outcomes included changes from baseline in patient reported outcome measures and evaluation of disease-modification using quantitative MRI. Treatment was well tolerated with no treatment-related serious adverse events. MAG200 cohorts reported a greater proportion of responders than placebo and demonstrated clinical and statistically significant improvement in pain and clinically relevant improvement in all KOOS subscales. MAG200 demonstrated a reproducible treatment effect over placebo, which was clinically relevant for pain in the 10 ​× ​10⁶ dose cohort (mean difference NPRS:-2.25[95%CI:-4.47,-0.03, p ​= ​0.0468]) and for function in the 20 ​× ​10⁶ and 100 ​× ​10⁶ dose cohorts (mean difference KOOS_ADL:10.12[95%CI:-1.51,21.76, p ​= ​0.0863] and 10.81[95%CI:-1.42,23.04, p ​= ​0.0810] respectively). A trend in disease-modification was observed with improvement in total knee cartilage volume in MAG200 10, 20, and 100 ​× ​10⁶ dose cohorts, with progression of osteoarthritis in placebo, though this was not statistically significant. No clear dose response was observed. This early-phase study provides supportive safety and efficacy evidence to progress MAG200 to later-stage trial development. ACTRN12617001095358/ACTRN12621000622808.

Aim: To evaluate the safety and efficacy of adipose-derived mesenchymal stem cell (ADMSC) therapy in combination with arthroscopic abrasion arthroplasty (AAA) in advanced knee osteoarthritis (OA). Materials & methods: 27 patients with Grade IV OA of the knee underwent AAA and ADMSC therapy (50 × 106 ADMSCs at baseline and 6 months). Clinical outcome was assessed over 36 months. Structural change was determined using MRI. Results: Treatment was well tolerated with no serious adverse events. Clinically significant improvements in pain and function were observed. Reproducible hyaline-like cartilage regeneration was seen in all participants. Conclusion: ADMSC therapy combined with AAA in Grade IV OA results in reproducible pain, functional and structural improvements. This represents a joint preservation technique for patients with advanced OA of the knee. Trial registration number: ACTRN12617000638336.