"One-step" bone marrow-derived cells transplantation and joint debridement for osteochondral lesions of the talus in ankle osteoarthritis: clinical and radiological outcomes at 36 months

[Mid- and long-term effectiveness analysis of distraction arthroplasty in treatment of moderate to severe ankle arthritis]

OBJECTIVE

To investigate the mid- and long-term effectiveness of external fixator distraction arthroplasty in the treatment of moderate to severe ankle arthritis.

METHODS

The clinical data of 23 patients with moderate to severe ankle arthritis treated with external fixation distraction arthroplasty who met the selection criteria between January 2007 and November 2019 were retrospectively analyzed. There were 20 males and 3 females; the age ranged from 21 to 65 years, with an average age of 43.7 years. Etiology included 8 cases of primary ankle arthritis, in which 5 cases combined with varus deformity; 15 cases of traumatic ankle arthritis, the cause of injury was 5 cases after ankle fracture surgery, 3 cases after Pilon fracture surgery, 5 cases of chronic ankle instability and repeated sprain, and 2 cases of other causes. According to Takakura staging system, there were 4 cases of stage ⅢA, 12 cases of stage ⅢB, and 7 cases of stage Ⅳ; according to Giannini staging system, there were 5 cases of stage Ⅱ and 18 cases of stage Ⅲ; according to Cheng staging system, 16 cases were in stage Ⅲ, and 7 cases stage Ⅳ. American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and visual analogue scale (VAS) score were used to evaluate the improvement of ankle pain and function before operation and at last follow-up, and the data were analyzed according to different etiological groups. At last follow-up, the surgical results were evaluated subjectively and objectively. The changes of ankle joint space before operation and at last follow-up were compared. The patients were divided into two groups according to their age: ≤45 years old group [young group, 10 cases, aged (35.62±7.41) years old] and >45 years old group [middle-aged and elderly group, 13 cases, aged (54.20±6.20) years old]. The AOFAS ankle-hindfoot score and VAS score were compared before and after operation between the two groups, and the influence of age on distraction arthroplasty was analyzed.

RESULTS

The external fixator was removed after 3 months of continuous distraction,12 patients got infection around the wire tunnels. All the 23 patients were followed up 13-143 months, with an average of 56.9 months; the follow-up time was (43.46±32.77) months and (69.80±37.79) months in the young group and middle-aged and elderly group, respectively. At last follow-up, the AOFAS ankle-hindfoot score and VAS score significantly improved when compared with those before operation ( P<0.05). According to etiological analysis, there was no significant difference in AOFAS ankle-hindfoot score and VAS score before and after operation ( P>0.05) in Pilon fracture patients, while the significant difference was found in remaining patients ( P<0.05). There was significant difference in AOFAS ankle-hindfoot score before operation between the young group and the middle-aged and elderly group ( t=2.110, P=0.040), but no significant difference in preoperative VAS score and the differences in VAS score and AOFAS ankle-hindfoot score before and after operation between the two groups ( P>0.05). The subjective and objective results of pain evaluation at last follow-up showed that 4 patients had no pain, 12 patients had moderate pain relief, 5 patients had mild pain relief, and 2 patients had no significant pain relief; among the 10 patients who were followed up more than 5 years, there were 2, 5, 2, and 1 patient, respectively; 2 patients who were followed up more than 10 years had moderate pain relief. At last follow-up, the ankle joint space was (3.7±0.4) mm, which significantly increased when compared with before operation [(1.5±0.2) mm] ( t=1.791, P=0.002). The ankle joint space was (2.9±0.5) mm in 10 patients who were followed up more than 5 years, and 3.3 mm and 3.0 mm in 2 patients who were followed up more than 10 years.

CONCLUSION

Distraction arthroplasty of the ankle joint can achieve satisfactory results in patients with moderate to severe ankle arthritis (except for arthritis caused by Pilon fracture), and age has no significant effect on distraction arthroplasty.

Outcomes of bone marrow aspirate concentrate and matrix-induced chondrogenesis (BMIC) for treatment of osteochondral lesions of the talus

BACKGROUND

To analyze the outcomes of Bone marrow aspirate concentrate and Matrix-Induced Chondrogenesis (BMIC) in Osteochondral Lesions of the Talus (OLTs).

METHODS

Patients with OLTs treated with BMIC from June 2013 to July 2020 were included. Visual Analogue Scale (VAS), Foot Function Index (FFI), and Foot Ankle Outcome Score (FAOS) before treatment and at last follow-up were subjected to analysis.

RESULTS

Forty-five patients were included and mean follow-up was 39.1 months (range, 13-97 months). Mean lesion size and depth were 180.7 ± 110.4 mm² and 9.6 ± 3.7 mm, respectively. BMIC was performed without malleolar osteotomy in 36 patients (80%) and bone graft was performed in 42 (93.3%). VAS, FFI, and FAOS improved significantly. No complication occurred and no revision was required.

CONCLUSIONS

The BMIC procedure is feasible and should be considered a viable treatment option for OLTs associated with large subchondral bone defects.

One-year follow-up data from the German Cartilage Registry (KnorpelRegister DGOU) in the treatment of chondral and osteochondral defects of the talus

INTRODUCTION

Chondral and osteochondral lesions of the talus (OLTs) remain a challenging issue with numerous operative treatments proposed to date. The aim of this study was to evaluate 1-year follow-up data in the German Cartilage Registry (KnorpelRegister DGOU).

METHODS

Among 401 patients in the database, 114 patients with a complete 1-year Foot and Ankle Outcome (FAOS) score for subscale Pain as the primary variable were included. A total of 12 different surgical treatments were performed. However, 8 techniques were carried out in negligible numbers of patients (n = 1-3), leaving 89 patients treated with the following techniques: arthroscopic antegrade bone marrow stimulation (group A; n = 32), autologous chondrocyte implantation with autologous cancellous bone grafting (group B; n = 9), matrix-augmented bone marrow stimulation (group C; n = 22), and matrix-augmented bone marrow stimulation with autologous cancellous bone grafting (group D; n = 26). Group differences and possible influencing variables such as age and sex were evaluated. Level of significance was set at p < 0.05 for all statistical tests.

RESULTS

All four treatment groups showed significant improvement of the FAOS scores at 1 year postoperatively compared with their preoperative scores. No significant differences were found with respect to score changes among the groups. A positive correlation between FAOS subscale Pain improvement and defect size volume and negative correlations between increasing age and FAOS subscales Sports/Rec and QoL were found. Concomitant ankle stabilization led to greater improvement in FAOS subscales Symptoms and ADL than in patients with no stabilization. FAOS subscale Pain showed greater improvement in women than in men.

CONCLUSION

All analyzed treatment options were effective for treatment of OLTs. In particular, large defects appeared to benefit from treatment. In the presence of concomitant ankle instability, a stabilizing procedure appeared to have a positive impact on the outcome.

Bone marrow aspirate concentrate and scaffold for osteochondral lesions of the talus in ankle osteoarthritis: satisfactory clinical outcome at 10 years

PURPOSE

To evaluate at long-term follow-up patients undergoing a one-step procedure of debridement and BMAC seeded in situ onto a scaffold for the treatment of osteochondral lesions of the talus (OLT) in ankles affected by osteoarthritis (OA), documenting the duration of the clinical benefit and its efficacy in postponing end-stage procedures.

METHODS

This series included 56 consecutive patients. Patients were evaluated preoperatively and up to a mean of 10 years of follow-up with the AOFAS score and the AOS scale, including pain and disability subscales. Furthermore, patients were asked to rate the satisfaction and failures were documented as well.

RESULTS

The AOFAS score improved from 52.3 ± 14.3 to 73.5 ± 23.1 at 10 years (p  < 0.0005); the AOS pain and disability subscales decreased from 70.9 ± 14.1 to 37.2 ± 32.7 and from 69.0 ± 14.8 to 34.2 ± 29.3, respectively (both p < 0.0005). The overall rate of satisfaction was 61.8 ± 41.2 and 68.6% of patients would undergo again the surgical procedure. A total of 17 failures was documented, for a failure rate of 33.3%. Older patients and those with more complex cases requiring previous or combined surgeries had lower outcomes, as well as those affected by grade 3 OA, who experienced a high failure rate of 71.4%.

CONCLUSIONS

This one-step technique for the treatment of OLT in OA ankles showed to be safe and to provide a satisfactory outcome, even if patients with end stage OA presented a high revision rate at 10 years. Moreover, this procedure was effective over time, with overall good results maintained up to a long-term follow-up. However, older age, more complex cases requiring previous or combined surgeries, and advanced OA led to an overall worst outcome and a significantly higher failure rate.

Chondral Lesions of the Knee: An Evidence-Based Approach

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Management of chondral lesions of the knee is challenging and requires assessment of several factors including the size and location of the lesion, limb alignment and rotation, and the physical and mental health of the individual patient.

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There are a multitude of options to address chondral pathologies of the knee that allow individualized treatment for the specific needs and demands of the patient.

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Osteochondral autograft transfer remains a durable and predictable graft option in smaller lesions (<2 cm2) in the young and active patient population.

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Both mid-term and long-term results for large chondral lesions (≥3 cm2) of the knee have demonstrated favorable results with the use of osteochondral allograft or matrix-associated chondrocyte implantation.

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Treatment options for small lesions (<2 cm2) include osteochondral autograft transfer and marrow stimulation and/or microfracture with biologic adjunct, while larger lesions (≥2 cm2) are typically treated with osteochondral allograft transplantation, particulated juvenile articular cartilage, or matrix-associated chondrocyte implantation.

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Emerging technologies, such as allograft scaffolds and cryopreserved allograft, are being explored for different graft sources to address complex knee chondral pathology; however, further study is needed.

Two-Year Follow-Up and Remodeling Kinetics of ChonDux Hydrogel for Full-Thickness Cartilage Defect Repair in the Knee

OBJECTIVE

To determine performance and repair kinetics of the ChonDux hydrogel scaffold for treating focal articular cartilage defects in the knee over 24 months.

DESIGN

This assessor-blinded trial evaluates ChonDux hydrogel scaffold implantation in combination with microfracture in 18 patients across 6 sites. Male and female patients 18 to 65 years of age with full-thickness femoral condyle defects 2 to 4 cm² in area were enrolled. Eligible patients received ChonDux treatment followed by rehabilitation. Defect volume fill was evaluated after 3, 6 (primary outcome), 12, 18, and 24 months by assessor blinded magnetic resonance imaging (MRI) analysis. Secondary outcomes were T2-weighted MRI relaxation time and patient surveys via visual analogue scale (VAS) pain and International Knee Documentation Committee (IKDC) knee function scoring.

RESULTS

ChonDux maintained durable tissue restoration over 24 months with final defect percent fill of 94.2% ± 16.3% and no significant loss of fill volume at any time points. Tissues treated with ChonDux maintained T2 relaxation times similar to uninjured cartilage between 12 and 24 months. VAS pain scoring decreased between 1 and 6 weeks, and IKDC knee function scores improved by approximately 30.1 with ChonDux over 24 months.

CONCLUSION

ChonDux treatment is a safe adjunct to microfracture therapy and promotes stable restoration of full thickness articular cartilage defects for at least 24 months.

Surgical treatment of talar osteo-chondral lesions with micro-fractures, mesenchymal cells grafting on membrane, or allograft: Mid-term clinical and magnetic resonance assessment

Talar dome osteo-chondral lesions (OCL) are defects of the cartilaginous surface and subchondral bone often associated with sport practice. This retrospective observational work has the purpose of assessing: a) The clinical outcomes in the patients study group and in the three sub-groups; b) medium-term morphological and qualitative outcomes of the newly formed tissue by magnetic resonance imaging; c) if there is the correlation between new formed tissue clinical, morphological RM evaluation and qualitative clinical outcomes.

The efficacy of different sources of mesenchymal stem cells for the treatment of knee osteoarthritis

Osteoarthritis (OA) is a common cause of chronic pain and disability. Regenerative therapies using mesenchymal stem cells (MSCs) provide an option for OA treatment as it could potentially regenerate the damaged cartilage. Bone marrow, adipose tissue and synovium are common MSC sources. The aim is to compare the therapeutic effect of MSCs from bone marrow, adipose tissue and synovium; combining its differentiation potential and accessibility, to decide the optimal source of MSCs for the treatment of knee OA. A comparison of preclinical and clinical studies using MSCs has been made with regard to treatment outcomes, isolation procedure and differentiation potential. All types of MSCs are effective at improving the clinical and structural condition of OA patients, but the longevity of the treatment, i.e. an effect that is maintained for at least 2 years, cannot be guaranteed. This review highlighted great variations in selection criteria and culture expansion conditions of MSCs between the literature and clinical trials. It also emphasised a substantial diversity and lack of consistency in the assessment mythology of clinical outcome after completion of MSC therapies procedures. A more cohesive methodology is required to evaluate the outcome of MSC treatments using quantitative and standardised frameworks in order to be able to directly compare results. Larger population of patients are recommended to assess the quality of MSC when designing studies and clinical trials to reaffirm the efficacy of MSC treatment prior to and within the clinical trials and follow up studies.

Stability of supramalleolar osteotomies using different implants in a sawbone model

BACKGROUND

With ankle arthritis often affecting young patients, joint-sparing treatments instead of total joint replacement should be considered. Only a few implants were specially developed for supramalleolar osteotomies (SMOT). This study was performed to analyse the stability of different implants and their appropriateness for SMOT.

METHODS

Twenty-five bone models (Sawbone Europe, Malmö, Sweden) were used for biomechanical testing. SMOT were performed as a uniplanar osteotomy, leaving 5 mm of lateral bone intact with a standardized gap of 8 mm. Five different plates commonly used for SMOT were assessed. For axial stability, the constructs were tested during 100 cycles for each load (150N and 800N) at a rate of 0.5 Hz. For rotational stability, each construct was subject to 100 cycles of 5 Nm torque at a rate of 0.25 Hz, performing three runs with an axial preload of 0N, 150N, or 800N. Ultimate axial load was performed for one-half and ultimate rotational load was performed for the other half of the constructs. In addition, the stiffness of the different constructs after failure was tested.

RESULTS

All constructs showed high stability and could be tested until maximum cyclic load. There was no significant difference between the five plates, neither for stiffness (axial or rotational) nor for failure load (axial or rotational). One plate indicated superiority in axial failure testing without any significant difference.

CONCLUSION

All implants could be tested until maximum load. The intact hinge apparently provides enough support to compensate for lower moment of inertia of some plates.

LEVEL OF EVIDENCE

Not applicable.

Stem Cells in Osteochondral Tissue Engineering

Mesenchymal stem cells (MSCs) are pluripotent stem cells with the ability to differentiate into a variety of other connective tissue cells, such as chondral, bony, muscular, and tendon tissue. Bone marrow-derived MSCs are pluripotent cells that can differentiate among others into osteoblasts, adipocytes and chondrocytes.Bone marrow-derived cells may represent the future in osteochondral repair. A one-step arthroscopic technique is developed for cartilage repair, using a device to concentrate bone marrow-derived cells and collagen powder or hyaluronic acid membrane as scaffolds for cell support and platelet gel.The rationale of the "one-step technique" is to transplant the entire bone-marrow cellular pool instead of isolated and expanded mesenchymal stem cells allowing cells to be processed directly in the operating room, without the need for a laboratory phase. For an entirely arthroscopic implantation are employed a scaffold and the instrumentation previously applied for ACI; in addition to these devices, autologous platelet-rich fibrin (PRF) is added in order to provide a supplement of growth factors. Results of this technique are encouraging at mid-term although long-term follow-up is still needed.

How far have biological therapies come in regenerative sports medicine?

INTRODUCTION

Regular engagement in sports produces many health benefits, but also exposes to increased injury risk. The quality of medical care available is crucial not only for sports trauma but also to avoid overuse syndromes and post-traumatic degenerative conditions.

AREAS COVERED

We provide background information on some clinical needs in sport injuries and describe the main families of biological products used in clinical practice. We also discuss limitations of the current clinical experience.

EXPERT OPINION

Sport and exercise impairment affects different segments of the population with different needs. The exceptional demands of elite athletes and subsequent media coverage have created hype around regenerative therapies. Statistical evidence, whether weak (cell products) or moderate (PRPs), is not enough to drive medical decisions because of the heterogeneity of the biological products available and their application procedures. Moreover, the specific needs of the different segments of the population along with the available clinical evidence for each musculoskeletal condition should be considered in the decision-making process. There is urgent need to develop regenerative protocols combined with post-intervention rehabilitation, and gather meaningful clinical data on the safety and efficacy of these interventions in the different populations segments.

Biological Therapies in Regenerative Sports Medicine

Regenerative medicine seeks to harness the potential of cell biology for tissue replacement therapies, which will restore lost tissue functionality. Controlling and enhancing tissue healing is not just a matter of cells, but also of molecules and mechanical forces. We first describe the main biological technologies to boost musculoskeletal healing, including bone marrow and subcutaneous fat-derived regenerative products, as well as platelet-rich plasma and conditioned media. We provide some information describing possible mechanisms of action. We performed a literature search up to January 2016 searching for clinical outcomes following the use of cell therapies for sports conditions, tendons, and joints. The safety and efficacy of cell therapies for tendon conditions was examined in nine studies involving undifferentiated and differentiated (skin fibroblasts, tenocytes) cells. A total of 54 studies investigated the effects of mesenchymal stem-cell (MSC) products for joint conditions including anterior cruciate ligament, meniscus, and chondral lesions as well as osteoarthritis. In 22 studies, cellular products were injected intra-articularly, whereas in 32 studies MSC products were implanted during surgical/arthroscopic procedures. The heterogeneity of clinical conditions, cellular products, and approaches for delivery/implantation make comparability difficult. MSC products appear safe in the short- and mid-term, but studies with a long follow-up are scarce. Although the current number of randomized clinical studies is low, stem-cell products may have therapeutic potential. However, these regenerative technologies still need to be optimized.

Osteoarthritis and stem cell therapy in humans: a systematic review

OBJECTIVE

Osteoarthritis (OA) is a leading cause of disability in the world. Mesenchymal stem cells (MSCs) have been studied to treat OA. This review was performed to systematically assess the quality of literature and compare the procedural specifics surrounding MSC therapy for osteoarthritis.

DESIGN

PubMed, CINAHL, EMBASE and Cochrane Central Register of Controlled Trials were searched for studies using MSCs for OA treatment (final search December 2017). Outcomes of interest included study evidence level, patient demographics, MSC protocol, treatment results and adverse events. Level I and II evidence articles were further analyzed.

RESULTS

Sixty-one of 3,172 articles were identified. These studies treated 2,390 patients with osteoarthritis. Most used adipose-derived stem cells (ADSCs) (n = 29) or bone marrow-derived stem cells (BMSCs) (n = 30) though the preparation varied within group. 57% of the sixty-one studies were level IV evidence, leaving five level I and nine level II studies containing 288 patients to be further analyzed. Eight studies used BMSCs, five ADSCs and one peripheral blood stem cells (PBSCs). The risk of bias in these studies showed five level I studies at low risk with seven level II at moderate and two at high risk.

CONCLUSION

While studies support the notion that MSC therapy has a positive effect on OA patients, there is limited high quality evidence and long-term follow-up. The present study summarizes the specifics of high level evidence studies and identifies a lack of consistency, including a diversity of MSC preparations, and thus a lack of reproducibility amongst these articles' methods.

Percutaneous Ultrasound-Guided Musculoskeletal Applications of Autologous Bone Marrow Aspirate Concentrate: Preliminary Experience From a Single Institution

Emerging musculoskeletal applications for local administration of autologous bone marrow aspirate concentrate (BMAC) include treatment of fractures, osteonecrosis, osteochondral injuries, osteoarthritis, ligament injury, tendon injury, and tendonopathies. Ultrasound-guided technique for various BMAC injection sites is detailed in this technical report and our preliminary clinical experience outlined.Five patients, 1 woman and 4 men, were treated with 6 peri/intratendinous (n = 4) or intraarticular (n = 2) BMAC injections between July 5, 2015 and December 31, 2016 for the clinical indications of common hamstrings origin tendinosis (n = 4), hip labral tear (n = 1), and osteochondral lesion of the talus (n = 1).All procedures were technically successful, with BMAC locally administered to the therapeutic target and no procedural complications observed. Clinical follow-up was available for 5 of 6 procedures. Four of 5 injections resulted in self-reported symptomatic improvement (clinical follow-up range, 2-12 months). One 72-year-old man with right common hamstrings origin tendinosis reported no improvement after BMAC injection.The technology is now available to support ultrasound-guided, autologous BMAC administration by the musculoskeletal interventionalist for common indications. Our initial clinical experience is consistent with early reports in the literature. This technique is well tolerated by symptomatic patients on an outpatient basis, and rates of self-reported symptomatic relief are high. Mechanism of action, long-term safety, and long-term clinical efficacy remain largely undefined.

Distraction arthroplasty compared to other cartilage preservation procedures in patients with post-traumatic arthritis: a systematic review

Post-traumatic arthritis (PTA) is characterized by the deterioration of articular cartilage temporally associated with an articular injury. With a paucity of literature comparing joint preservation techniques, we performed a systematic review of the literature intending to describe and summarize the results of ankle distraction arthroplasty as it compares with studies on tibio-talar microfracture, allograft, and autograft for ankle joint preservation in the post-traumatic population under 50 years of age. Research databases were searched and abstracts screened for relevance on our topic of interest. Abstracts meeting screening criteria with high interobserver reliability underwent full-manuscript review and coding for pertinent citation, study level, treatment, and outcome variables. Outcome variables for patient-reported pain scales, validated outcome measurement tools, radiographic progression, reoperation/re-treatment rates, and complication rates were recorded. Out of 105 unique citations, 10 publications were included. The distraction arthroplasty studies had 36 out of 181 patients requiring reoperation for complications (19.9%), while other joint-preserving procedures studies had 40 out of 177 patients requiring reoperations for complications (22.6%). Clinical outcome scores at mean follow-up time ranging from 2 to 10 years between studies were similar. Reported results for a variety of cartilage preservation procedures, including distraction arthroplasty, are satisfactory and reoperation rates for complication are similar. Limitations in available data and underlying study quality affect synthesis of the results therein. While distraction arthroplasty is an option for cartilage preservation in patients with PTA of the ankle, the technique is highly specialized which may affect the external validity.

Level of evidence: III.

[Therapeutic utilization of stem cells in orthopedics]

Stem cells are becoming increasingly more important in the field of regenerative medicine. Adult mesenchymal stem cells (MSCs) are harvested predominantly from bone marrow or adipose tissue, are already being used in the clinical setting and have a low potential for side effects. In orthopedics, experience has been gained in the treatment of bone defects, non-unions, cartilage defects, osteoarthritis and tendon pathologies. The current data are derived from case studies and randomized controlled trials are missing; therefore, there are many open questions concerning the optimal cell source, number of cells, administration technique (e.g. injections and matrices) or combinations with growth factors; however, it is evident from the data that MSCs have a positive effect on tissue regeneration and are safe to use.

Comparative Clinical Observation of Arthroscopic Microfracture in the Presence and Absence of a Stromal Vascular Fraction Injection for Osteoarthritis

Osteoarthritis (OA) is a degenerative cartilage disease that is characterized by a local inflammatory reaction. Consequently, many studies have been performed to identify suitable prevention and treatment interventions. In recent years, both arthroscopic microfracture (AM) and stem cell therapy have been used clinically to treat OA. This study aimed to evaluate the clinical effects of AM in the presence and absence of a stromal vascular fraction (SVF) injection in the management of patients with OA. Thirty patients with grade 2 or 3 (Lawrence scale) OA of the knee participated in this study. Placebo group patients (n = 15) received AM alone; treatment group patients (n = 15) received AM and an adipose tissue‐derived SVF injection. The SVF was suspended in platelet‐rich plasma (PRP) before injection into the joint. Patient groups were monitored and scored with the Western Ontario and McMaster Universities Arthritis Index (WOMAC), Lysholm, Visual Analog Pain Scale (VAS), and modified Outerbridge classifications before treatment and at 6, 12, and 18 months post‐treatment. Bone marrow edema was also assessed at these time points. Patients were evaluated for knee activity (joint motion amplitude) and adverse effects relating to surgery and stem cell injection. Treatment efficacy was significantly different between placebo and treatment groups. All treatment group patients had significantly reduced pain and WOMAC scores, and increased Lysholm and VAS scores compared with the placebo group. These findings suggest that the SVF/PRP injection efficiently improved OA for 18 months after treatment. This study will be continuously monitored for additional 24 months. Stem Cells Translational Medicine2017;6:187–195

Stem cells in articular cartilage regeneration

Mesenchymal stem cells (MSCs) have emerged as a promising option to treat articular defects and early osteoarthritis (OA) stages. However, both their potential and limitations for a clinical use remain controversial. Thus, the aim of this systematic review was to examine MSCs treatment strategies in clinical settings, in order to summarize the current evidence of their efficacy for the treatment of cartilage lesions and OA.Among the 60 selected studies, 7 were randomized, 13 comparative, 31 case series, and 9 case reports; 26 studies reported the results after injective administration, whereas 33 used surgical implantation. One study compared the two different modalities. With regard to the cell source, 20 studies concerned BMSCs, 17 ADSCs, 16 BMC, 5 PBSCs, 1 SDSCs, and 1 compared BMC versus PBSCs. Overall, despite the increasing literature on this topic, the evidence is still limited, in particular for high-level studies. On the other hand, the available studies allow to draw some indications. First, no major adverse events related to the treatment or to the cell harvest have been reported. Second, a clinical benefit of using MSCs therapies has been reported in most of the studies, regardless of cell source, indication, or administration method. This effectiveness has been reflected by clinical improvements and also positive MRI and macroscopic findings, whereas histologic features gave more controversial results among different studies. Third, young age, lower BMI, smaller lesion size for focal lesions, and earlier stages of OA joints have been shown to correlate with better outcomes, even though the available data strength does not allow to define clear cutoff values. Finally, definite trends can be observed with regard to the delivery method: currently cultured cells are mostly being administered by i.a. injection, while one-step surgical implantation is preferred for cell concentrates. In conclusion, while promising results have been shown, the potential of these treatments should be confirmed by reliable clinical data through double-blind, controlled, prospective and multicenter studies with longer follow-up, and specific studies should be designed to identify the best cell sources, manipulation, and delivery techniques, as well as pathology and disease phase indications.