Allogenic umbilical cord blood-derived mesenchymal stromal cell implantation was superior to bone marrow aspirate concentrate augmentation for cartilage regeneration despite similar clinical outcomes

Prognostic Factors for Clinical Outcome and Cartilage Regeneration after Implantation of Allogeneic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Large-Sized Cartilage Defects with Osteoarthritis

OBJECTIVE

To analyze the prognostic factors for clinical outcomes and cartilage regeneration after the implantation of allogeneic human umbilical cord blood mesenchymal stem cell (hUCB-MSC) for treating large-sized cartilage defects with osteoarthritis.

DESIGN

This study is a case-series with multiple subgroup analyses that divides the included patients into multiple subgroups based on various factors. Overall, 47 patients who underwent hUCB-MSC implantation were included. The patient-reported outcomes, magnetic resonance imaging (MRI), and second-look arthroscopy were used to assess the outcomes.

RESULTS

Combined realignment surgery significantly correlated with clinical outcomes, particularly pain. No other factors significantly influenced the clinical outcomes in short-term period. Subgroups with large defect sizes or meniscal insufficiency showed significantly poor MRI and arthroscopy outcomes (MRI, P = 0.001, P = 0.001; arthroscopy, P = 0.032, P = 0.042). The logistic regression showed that patients with a 1 cm2 larger defect size were 1.91 times less likely to achieve favorable MRI outcomes (P = 0.017; odds ratio [OR], 1.91). Cut-off value to predict the poor outcome was >5.7 cm2 (area under the curve, 0.756). A cartilage defect size >5.7 cm2 was the major poor prognostic factor for cartilage regeneration on MRI (P = 0.010; OR, 17.46). If the postoperative alignment shifted by 1° opposite to the cartilage defect, it was 1.4 times more likely to achieve favorable MRI outcomes (P = 0.028; OR, 1.4).

CONCLUSION

Combining realignment surgery showed a better prognosis for pain improvement. Cartilage defect size, meniscal function, and postoperative alignment are significant prognostic factors for cartilage regeneration. A cartilage defect size >5.7 cm2 was significantly related to poor cartilage regeneration.

Management of knee osteoarthritis using bone marrow aspirate concentrate: a systematic review

INTRODUCTION

Knee osteoarthritis (OA) is a common degenerative joint condition and a major cause of disability in the general population.

SOURCE OF DATA

Recent published literature identified from PubMed, EMBASE, Google Scholar, and Scopus.

AREAS OF AGREEMENT

Orthobiological therapies try to regenerate articular cartilage and stop the progression of the degenerative lesion. Intra-articular injections of biological derivates have been increasingly used in the last decade.

AREAS OF CONTROVERSY

The indications for the use of bone marrow aspirate concentrate (BMAC) are still unclear.

GROWING POINTS

We systematically reviewed the current literature on BMAC in the management of knee OA, giving an update on the current indications for the selection of the ideal patient and the preparations and efficacy of BMAC compared to other biological alternatives.

AREAS TIMELY FOR DEVELOPING RESEARCH

BMAC is a valuable source of mesenchymal stem cells, offering potential benefits in attenuating the inflammatory pathway associated with knee OA. Intra-articular injection of BMAC has shown effectiveness in clinical trials improving functional outcomes of knee OA patients. The superiority of BMAC over other orthobiological treatments cannot be assessed because of conflicting results.

Intra-articular interventions in osteoarthritis: Navigating the landscape of hyaluronic acid, mesenchymal stem cells, and platelet-rich plasma

Osteoarthritis (OA) poses a substantial burden on patients, leading to pain, functional decline, and reduced quality of life. While conventional treatments focus on symptom management, disease-modifying interventions are yet to be established. This review explores the efficacy of intra-articular interventions, particularly hyaluronic acid (HA), mesenchymal stem cells (MSCs), and platelet-rich plasma (PRP), in the context of OA management. HA injections, with diverse formulations like Hylan G-F20, sodium hyaluronate, and hyaluronan, present varying outcomes, necessitating a nuanced understanding of their effectiveness and timing. MSC therapy, derived from adipose tissue, umbilical cord, or bone marrow, shows promising results in clinical improvement, with adipose-derived MSCs demonstrating efficacy in maintaining benefits over 6 mo. Conversely, bone-marrow-derived MSCs show limited effectiveness, highlighting the need for source-specific considerations. PRP has emerged as a superior option for long-term pain reduction and quality of life improvement, with leukocyte-poor formulations and a critical platelet count of 10 billion demonstrating optimal results. This comprehensive analysis underscores the potential of intra-articular interventions in OA management, emphasizing the need for personalized and evidence-based approaches to enhance treatment efficacy and patient outcomes.

Should I add orthobiologics to my knee osteotomy practice? A systematic review

IMPORTANCE

Orthobiologics has seen a renaissance over the last decade as an adjunct therapy during osteotomy due to the limited inherent regenerative potential of damaged intraarticular tissues.

AIM OR OBJECTIVE

This systematic review aims to present the latest evidence regarding using orthobiologics with simultaneous high tibial osteotomy (HTO) for knee osteoarthritis. The results of this study may guide surgeons to improve their clinical results and clear the air regarding confusion over whether or not to add orthobiologics to HTO in clinical practice backed by scientific evidence.

EVIDENCE REVIEW

According to PRISMA guidelines a systematic search for relevant literature was performed in the PubMed (MEDLINE), Scopus, EMBASE, and Cochrane Library databases of all studies published in English from January 1990 to May 2023. The following search terms were entered into the title, abstract, and keyword fields: "knee" or "osteotomy" AND "valgus" or "varus" AND "regenerative medicine" or "PRP" or "mesenchymal stem cells" or "stem cells" or "BMAC" or "bone marrow" or "growth factors" or "umbilical cord blood-derived mesenchymal stem cell" or "stromal vascular fraction". The AMSTAR-2 checklist was used to confirm the quality of the systematic review. Randomised controlled trials (RCTs), prospective and retrospective comparative cohort studies, case-control studies, and case series were included. Studies that reported clinical outcomes in patients treated with knee osteotomy for varus/valgus knee with concomitant adjunction of regenerative treatment [Platelet-rich plasma (PRP), Adipose-derived stem cells (ADSC), Human Umbilical Cord Blood-Derived (HUCBD), Mesenchymal Stem Cells (MSC), bone marrow aspirate concentrate (BMAC), stromal vascular fraction (SVF)] were included. The outcome measures extracted from the studies were the KOOS score, Lysholm score, Subjective IKDC, WOMAC Score, KSS, Tegner, HSS, radiographic tibiofemoral angle, posterior tibial slope and complications. The current systematic review is registered in the PROSPERO Registry (CRD42023439379).

FINDINGS

Osteotomy for unicompartmental arthritis with adjunction of orthobiologics such as PRP, ADSC, HVCBD, MSC, BMAC, and SVF presents a consistent statistically significant clinical improvement compared to preoperative scores regardless of the treatment modality used and there were no notable complications associated with the use of these novel agents.

CONCLUSIONS AND RELEVANCE

Orthobiologics and knee osteotomies could improve outcomes in patients with knee osteoarthritis desiring Knee preservation surgeries. However, only a few studies are available on the topic to conclude anything with certainty, the patients included in the studies could not be disintegrated based on the grade of osteoarthritis (OA), type, dosage and frequency of administration of orthobiologic and type of additional surgical procedures used. Therefore, better-structured RCTs are required to implement this finding into routine Orthopaedic practice.

LEVEL OF EVIDENCE

Level 4.

Effects of concurrent cartilage procedures on cartilage regeneration in high tibial osteotomy: a systematic review

PURPOSE

This systematic review aimed to evaluate the effects of concurrent cartilage procedures on cartilage regeneration when performed alongside high tibial osteotomy (HTO).

MATERIALS AND METHODS

The systematic review followed the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). A comprehensive search was conducted on databases including PubMed, Embase, Cochrane Library, and Google Scholar, covering articles published until August 31, 2023.

RESULTS

Sixteen studies (1277 patients) revealed that HTO, with or without concurrent cartilage procedures, leads to cartilage regeneration based on the International Cartilage Repair Society (ICRS) grade during second-look arthroscopy. No concurrent procedure showed improvement in ICRS grade (mean difference: - 0.80 to - 0.49). Microfracture (mean difference: - 0.75 to - 0.22), bone marrow aspirate concentrate (BMAC) (mean difference: - 1.37 to - 0.67), and human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) (mean difference: - 2.46 to - 1.81) procedures also demonstrated positive outcomes. Clinical outcome assessments for each cartilage procedure were also improved during postoperative follow-up, and no specific complications were reported.

CONCLUSIONS

HTO with or without concurrent cartilage procedures promotes cartilage regeneration observed during second-look arthroscopy, with improved clinical outcomes. Future randomized controlled trials on the same topic, along with subsequent meta-analyses, are necessary for conclusive findings.

Allogeneic umbilical cord blood-derived mesenchymal stem cell implantation versus microdrilling combined with high tibial osteotomy for cartilage regeneration

This study compared cartilage regeneration outcomes in knee osteoarthritis (OA) using allogeneic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation and microdrilling with high tibial osteotomy (HTO). Fifty-four patients (60 knees) were included: 24 (27 knees) in the hUCB-MSC group and 30 (33 knees) in the microdrilling group. Both groups showed significant improvements in pain and functional scores at 6, 12, and 24 months compared to baseline. At 24 months, the hUCB-MSC group had significantly improved scores. Arthroscopic assessment at 12 months revealed better cartilage healing in the hUCB-MSC group. In subgroup analysis according to the defect site, hUCB-MSC implantation showed superior cartilage healing for anterior lesions. In conclusion, both treatments demonstrated effectiveness for medial OA. However, hUCB-MSC implantation had better patient-reported outcomes and cartilage regeneration than microdrilling. The study suggests promising approaches for cartilage restoration in large knee defects due to OA.

Return to Play After Knee Articular Cartilage Restoration: Surgical Options, Rehabilitation Protocols, and Performance Outcomes

PURPOSE OF REVIEW

Numerous cartilage restoration techniques have proven to be effective in the treatment of articular cartilage defects. The ultimate goal of these procedures is to improve pain and function, thereby increasing the likelihood of a patient's return to physical activity. Postoperative rehabilitation is a key component for a successful and expedient return to activities. The purpose of this article is to review the current literature regarding common surgical options, rehabilitation protocols, and performance outcomes after operative treatment of articular cartilage defects.

RECENT FINDINGS

Studies have demonstrated improved short- to long-term outcomes in a majority of techniques. However, the clinical benefits of microfracture are short-lived, which has led to the use of alternative procedures. Rehabilitation protocols are not standardized, but emphasis has been placed on bracing, weightbearing, early continuous passive range of motion, and strengthening to improve function. There is growing evidence to suggest that accelerated rehabilitation after matrix-induced autologous chondrocyte implantation may result in superior outcomes compared to delayed rehabilitation. Overall, most techniques result in satisfactory rates of return to play, though existing comparative studies typically include patients with heterogeneous pathology, complicating effective synthesis of outcomes data. In appropriately selected patients, cartilage restoration procedures after articular cartilage injury result in favorable patient-reported clinical outcomes and high rates of return to play. While studies emphasize the critical role that rehabilitation plays with respect to outcomes after surgery, there are substantial inconsistencies in protocols across techniques.

Mesenchymal stem cell implantation provides short-term clinical improvement and satisfactory cartilage restoration in patients with knee osteoarthritis but the evidence is limited: a systematic review performed by the early-osteoarthritis group of ESSKA-European knee associates section

PURPOSE

Implantation of mesenchymal stem cells (MSCs) is a potential cell-based modality for cartilage repair. Currently, its clinical use largely surrounds focal cartilage defect repair and intra-articular injections in knee osteoarthritis. The MSCs' implantation efficacy as a treatment option for osteoarthritis remains contentious. This systematic review aims to evaluate studies that focused on MSCs implantation in patients with knee OA to provide a summary of this treatment option outcomes.

METHODS

A systematic search was performed in PubMed (Medline), Scopus, Cinahl, and the Cochrane Library. Original studies investigating outcomes of MSCs implantations in patients with knee OA were included. Data on clinical outcomes using subjective scores, radiological outcomes, and second-look arthroscopy gradings were extracted.

RESULTS

Nine studies were included in this review. In all included studies, clinical outcome scores revealed significantly improved functionality and better postoperative pain scores at 2-3 years follow-up. Improved cartilage volume and quality at the lesion site was observed in five studies that included a postoperative magnetic resonance imaging assessment and studies that performed second-look arthroscopy. No major complications or tumorigenesis occurred. Outcomes were consistent in both single MSCs implantation and concurrent HTO with MSCs implantation in cases with excessive varus deformity.

CONCLUSION

According to the available literature, MSCs implantation in patients with mild to moderate knee osteoarthritis is safe and provides short-term clinical improvement and satisfactory cartilage restoration, either as a standalone procedure or combined with HTO in cases with axial deformity. However, the evidence is limited due to the high heterogeneity among studies and the insufficient number of studies including a control group and mid-term outcomes.

LEVEL OF EVIDENCE

IV.

Biological intra-articular augmentation for osteotomy in knee osteoarthritis: strategies and results : A systematic review of the literature from the ESSKA Orthobiologics Initiative

PURPOSE

To assess whether there is evidence supporting the use of augmentation strategies, either cartilage surgical procedures or injective orthobiologic options, to improve the results of osteotomies in knees with osteoarthritis (OA).

METHODS

A systematic review of the literature was performed on the PubMed, Web of Science and the Cochrane databases in January 2023 on osteotomies around the knee associated with augmentation strategies (either cartilage surgical procedures or injective orthobiologic options), reporting clinical, radiological, or second-look/histological outcomes at any follow-up. The methodological quality of the included studies was assessed with the Coleman Methodology Score (CMS).

RESULTS

Out of the 7650 records identified from the databases, 42 articles were included for a total of 3580 patients and 3609 knees treated; 33 articles focused on surgical treatments and 9 on injective treatments performed in association with knee osteotomy. Out of the 17 comparative studies with surgical augmentation, only 1 showed a significant clinical benefit of an augmentation procedure with a regenerative approach. Overall, other studies showed no differences with reparative techniques and even detrimental outcomes with microfractures. Regarding injective procedures, viscosupplementation showed no improvement, while the use of platelet-rich plasma or cell-based products derived from both bone marrow and adipose tissue showed overall positive tissue changes which translated into a clinical benefit. The mean modified CMS score was 60.0 ± 12.1.

CONCLUSION

There is no evidence to support the effectiveness of cartilage surgical treatments combined with osteotomies in terms of pain relief and functional recovery of patients affected by OA in misaligned joints. Orthobiologic injective treatments targeting the whole joint environment showed promising findings. However, overall the available literature presents a limited quality with only few heterogeneous studies investigating each treatment option. This ORBIT systematic analysis will help surgeons to choose their therapeutic strategy according to the available evidence, and to plan further and better studies to optimize biologic intra-articular osteotomy augmentation.

LEVEL OF EVIDENCE

Level IV.

Medial opening-wedge high tibial osteotomy with microfracture in treatment of varus medial compartmental knee osteoarthritis: clinical outcomes and second-look arthroscopic results

Objective: This study aimed to investigate the clinical outcomes of medial opening high tibial osteotomy (MOWHTO) combined with arthroscopic microfracture in the treatment of varus medial compartmental knee osteoarthritis and to assess cartilage regeneration using second-look arthroscopy. Methods: This study involved 86 patients (86 knees) who underwent MOWHTO and microfracture from August 2016 to August 2020, including 15 men and 71 women with an average age of 55.3 ± 7.6 years (range, 42-71 years). The patients underwent a second-look arthroscopy to evaluate the status of cartilage regeneration at the time of plate removal, an average of 2 years after the initial osteotomy. Clinical and radiological examinations were performed preoperatively and at the final follow-up visit. The radiologic evaluation included the weight-bearing line ratio (WBL ratio), mechanical femorotibial angle (FTA), medial proximal tibial angle (MPTA), posterior tibial slope angle (PTS) and Kellgren-Lawrence (KL) grade. Clinical outcomes were assessed using the Knee Society score (KSS) and International Knee Documentation Committee (IKDC) scores. Arthroscopic findings were assessed by macroscopic evaluation of cartilage repair according to the International Cartilage Repair Society (ICRS) grading system. Results: The mean KSS and IKDC scores significantly improved at the final follow-up compared to the scores obtained preoperatively (p < 0.05). At the time of plate removal, a second-look arthroscopic examination showed that the ICRS grade of the medial femoral condyle was as follows: grade I -11 cases, grade II -56, grade III-12, and grade IV-7, and cartilage regeneration was seen in 85% of knees (73/86). The ICRS grade of medial tibial plateau was grade I-12 cases, grade II-44, grade III-22, and grade IV-8, and cartilage regeneration was seen in 63% of knees (54/86). Significant differences were observed between cartilage regeneration and clinical outcomes (p < 0.05). Clinical results were better in the good cartilage regeneration group (grades I and II) than were in the poor cartilage regeneration group (grades III and IV). Conclusion: MOWHTO combined with arthroscopic microfracture can effectively improve clinical outcomes in the treatment of varus medial compartmental knee osteoarthritis. Cartilage regeneration can be promoted by correcting varus deformities, which affect clinical outcomes.

Therapeutic effects of different intervention forms of human umbilical cord mesenchymal stem cells in the treatment of osteoarthritis

Osteoarthritis (OA) is a common and disabling disease. For advanced OA, surgical treatment is still the main treatment. Human umbilical cord mesenchymal stem cells (hUC-MSCs) are self-regenerative pluripotent cells, that coordinate cartilage regeneration by secreting various trophic factors, which adjust the injured tissue environment. hUC-MSCs secret extracellular vesicles and participates in OA treatment by transmitting bioactive molecules related to migration, proliferation, apoptosis, inflammatory reaction, extracellular matrix synthesis and cartilage repair. In addition, the combination of multiple substances represented by cartilage matrix and hUC-MSCs also have a significant synergistic effect on OA treatment. Because hUC-MSCs have shown considerable promise in cartilage repair, some scholars have proposed transplanting mesenchymal stem cells into damaged cartilage to delay OA progression. This article reviews the application of hUC-MSCs as a treatment for OA. With the continuous development of routine clinical applications, more reliable intervention modalities for hUC-MSCs in OA treatment will be discovered for the time to come.

Adipose-Derived Stromal Vascular Fractions Are Comparable With Allogenic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells as a Supplementary Strategy of High Tibial Osteotomy for Varus Knee Osteoarthritis

Purpose

To compare the clinical, radiologic, and second-look arthroscopic outcomes of high tibial osteotomy (HTO) with stromal vascular fraction (SVF) implantation versus human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSC) transplantation and identify the association between cartilage regeneration and HTO outcomes.

Methods

Patients treated with HTO for varus knee osteoarthritis between March 2018 and September 2020 were retrospectively identified. In this retrospective study, among 183 patients treated with HTO for varus knee osteoarthritis between March 2018 and September 2020, patients treated with HTO with SVF implantation (SVF group; n = 25) were pair-matched based on sex, age, and lesion size with those who underwent HTO with hUCB-MSC transplantation (hUCB-MSC group; n = 25). Clinical outcomes were evaluated using the International Knee Documentation Committee score and Knee Injury and Osteoarthritis Outcome Score. Radiological outcomes evaluated were the femorotibial angle and posterior tibial slope. All patients were evaluated clinically and radiologically before surgery and during follow-up. The mean final follow-up periods were 27.8 ± 3.6 (range 24-36) in the SVF group and 28.2 ± 4.1 (range, 24-36) in the hUCB-MSC group (P = 0.690). At second-look arthroscopic surgery, cartilage regeneration was evaluated using the International Cartilage Repair Society (ICRS) grade.

Results

A total of 17 male and 33 female patients with a mean age of 56.2 years (range, 49-67 years) were included. At the time of second-look arthroscopic surgery (mean, 12.6 months; range, 11-15 months in the SVF group and 12.7 months; range, 11-14 months in the hUCB-MSC group, P = .625), the mean International Knee Documentation Committee score and Knee Injury and Osteoarthritis Outcome Score in each group significantly improved (P < .001 for all), and clinical outcomes at final follow-up further improved in both groups when compared with the values at second-look arthroscopic surgery (P < .05 for all). Overall ICRS grades, which significantly correlated with clinical outcomes, were similar between groups with no significant differences (P = .170 for femoral condyle and P = .442 for tibial plateau). Radiologic outcomes at final follow-up showed improved knee joint alignment relative to preoperative conditions but showed no significant correlation with clinical outcomes or ICRS grade in either group (P > .05 for all).

Conclusions

Improved clinical and radiological outcomes and favorable cartilage regeneration were seen after surgery for varus Knee OA in both SVF and hUCB-MSC groups.

Level of Evidence

Level III, retrospective comparative study.

A systematic review, umbrella review, and quality assessment on clinical translation of stem cell therapy for knee osteoarthritis: Are we there yet?

BACKGROUND

The success of stem cell therapy for knee osteoarthritis (KOA) in preclinical animal models has accelerated the pace of clinical translation. However, it remains uncertain whether the current scientific evidence supports the clinical application of stem cells in treating KOA. A comprehensive evaluation of the safety and efficacy of stem cell therapies and scientific evidence quality is necessary.

METHODS

Using "stem cells" and "knee osteoarthritis" as the search terms, several databases, including PubMed, Web of Science, Cochrane, Embase, and Clinicaltrials.gov, were searched on August 25, 2022, and updated on February 27, 2023. Clinical studies that reported adverse reactions (ARs) of stem cell therapy in KOA patients were included without limiting the type of studies. Quantitative systematic reviews of stem cell therapy for KOA that conducted meta-analysis were included. Two researchers conducted literature screening and data extraction independently, and the evidence quality was evaluated according to the Institute of Health Economics and AMSTAR 2 criteria.

RESULTS

Fifty clinical studies and 13 systematic reviews/meta-analyses (SRs/MAs) were included. Nineteen ARs were reported in 50 studies, including five knee-related ARs, seven common ARs, and seven other ARs. Some studies reported over 10% prevalence of knee pain (24.5%; 95% CI [14.7%, 35.7%]), knee effusion (12.5%; 95% CI [4.8%, 22.5%]), and knee swelling (11.9%; 95% CI [3.5%, 23.5%]). Additionally, two studies have reported cases of prostate cancer and breast tumors, respectively. However, these two studies suggest that stem cell therapy does not bring significant ARs to patients. SRs/MAs results revealed that stem cell therapy relieved pain in patients over time but did not improve knee function. However, current clinical studies have limited evidence regarding study objectives, test designs, and patient populations. Similarly, SRs/MAs have inadequate evidence regarding study design, risk of bias assessment, outcome description, comprehensive discussion, and potential conflicts of interest.

CONCLUSIONS

The inefficacy of stem cells, the risk of potential complications, and the limited quality of evidence from current studies precluded any recommendation for using stem cell products in patients with KOA. Clinical translation of stem cell therapies remains baseless and should be cautiously approached until more robust evidence is available. PROSPERO registration number: CRD42022355875.

Bone Marrow Aspirate Concentrate versus Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells for Combined Cartilage Regeneration Procedure in Patients Undergoing High Tibial Osteotomy: A Systematic Review and Meta-Analysis

Background and objectives: Cartilage regeneration using mesenchymal stem cells (MSCs) has been attempted to improve articular cartilage regeneration in varus knee osteoarthritis (OA) patients undergoing high tibial osteotomy (HTO). Bone marrow aspirate concentrate (BMAC) and human umbilical cord blood-derived MSCs (hUCB-MSCs) have been reported to be effective. However, whether BMAC is superior to hUCB-MSCs remains unclear. This systematic review and meta-analysis aimed to determine the clinical efficacy of cartilage repair procedures with BMAC or hUCB-MSCs in patients undergoing HTO. Materials and Methods: A systematic search was conducted using three global databases, PubMed, EMBASE, and the Cochrane Library, for studies in which the clinical outcomes after BMAC or hUCB-MSCs were used in patients undergoing HTO for varus knee OA. Data extraction, quality control, and meta-analysis were performed. To compare the clinical efficacy of BMAC and hUCB-MSCs, reported clinical outcome assessments and second-look arthroscopic findings were analyzed using standardized mean differences (SMDs) with 95% confidence intervals (CIs). Results: The present review included seven studies of 499 patients who received either BMAC (BMAC group, n = 169) or hUCB-MSCs (hUCB-MSC group, n = 330). Improved clinical outcomes were found in both BMAC and hUCB-MSC groups; however, a significant difference was not observed between procedures (International Knee Documentation Committee score; p = 0.91, Western Ontario and McMaster Universities OA Index; p = 0.05, Knee Society Score (KSS) Pain; p = 0.85, KSS Function; p = 0.37). On second-look arthroscopy, the hUCB-MSC group showed better International Cartilage Repair Society Cartilage Repair Assessment grade compared with the BMAC group (p < 0.001). Conclusions: Both BMAC and hUCB-MSCs with HTO improved clinical outcomes in varus knee OA patients, and there was no difference in clinical outcomes between them. However, hUCB-MSCs were more effective in articular cartilage regeneration than BMAC augmentation.

Allogeneic Umbilical Cord-Blood-Derived Mesenchymal Stem Cells and Hyaluronate Composite Combined with High Tibial Osteotomy for Medial Knee Osteoarthritis with Full-Thickness Cartilage Defects

Background and Objectives: Although the effects of cartilage repair in patients who are undergoing high tibial osteotomy (HTO) remains controversial, cartilage repair may be required for the full-thickness cartilage defect because of a concern of lower clinical outcome. The purpose of this study was to investigate clinical outcome and cartilage repair following implantation of allogeneic umbilical cord-blood-derived MSCs (UCB-MSCs)-hyaluronate composite in patients who received HTO for medial knee osteoarthritis (OA) with full-thickness cartilage defect. Materials and Methods: Inclusion criteria were patients with a medial knee OA, a full-thickness cartilage defect (International Cartilage Repair Society (ICRS) grade IV) ≥  3 cm² of the medial femoral condyle, and a varus deformity  ≥  5°. The full-thickness cartilage defect was treated with implantation of an allogeneic UCB-MSCs-hyaluronate composite following medial open-wedge HTO. Visual analogue scale for pain and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score were assessed at each follow-up. Cartilage repair was assessed by the ICRS cartilage repair assessment system at second-look arthroscopy when the plate was removed. Results: Twelve patients (mean age 56.1 years; mean defect size: 4.5 cm²) were included, and 10 patients underwent second-look arthroscopy during plate removal after a minimum of 1 year after the HTO. At the final follow-up of mean 2.9 years (range; 1-6 years), all clinical outcomes had improved. At second-look arthroscopy, repaired tissue was observed in all cases. One case (10%) showed grade I, seven (70%) cases showed grade II, and two (20%) cases showed grade III according to ICRS cartilage repair assessment system, which meant that 80% showed an overall repair assessment of "normal" or "nearly normal". Conclusion: Allogeneic UCB-MSCs-HA composite implantation combined with HTO resulted in favorable clinical outcome and cartilage repair in all cases. These findings suggest that UCB-MSCs-HA composite implantation combined with HTO would be a good therapeutic option for patients with knee OA and full-thickness cartilage defects.

AAOS Technology Overview Summary: Concentrated Bone Marrow Aspirate for Knee Osteoarthritis

The Concentrated Bone Marrow Aspirate (CBMA) for Knee Osteoarthritis Technology Overview is based on a systematic review of current scientific and clinical research. Through analysis of the current best evidence, this technology overview seeks to evaluate the efficacy of CBMA for patients with knee osteoarthritis. The systematic literature review resulted in 12 articles: three high-quality, four moderate-quality, and five low-quality. The findings of these studies were summarized to present findings on CBMA versus placebo and CBMA versus other treatment modalities. In addition, the work group highlighted areas for needed additional research when evidence proved lacking on the topic and carefully noted the potential harms associated with an intervention, required resource utilization, acceptability, and feasibility.

Cartilage Regeneration Using Human Umbilical Cord Blood Derived Mesenchymal Stem Cells: A Systematic Review and Meta-Analysis

Background and Objectives: Human umbilical-cord-blood-derived mesenchymal stem cells (hUCB-MSCs) have recently been used in clinical cartilage regeneration procedures with the expectation of improved regeneration capacity. However, the number of studies using hUCB-MSCs is still insufficient, and long-term follow-up results after use are insufficient, indicating the need for additional data and research. We have attempted to prove the efficacy and safety of hUCB-MSC treatment in a comprehensive analysis by including all subjects with knee articular cartilage defect or osteoarthritis who have undergone cartilage repair surgery using hUCB-MSCs. We conducted a meta-analysis and demonstrated efficacy and safety based on a systematic review. Materials and Methods: This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. For this study, we searched the PubMed, Embase, Web of Science, Scopus, and Cochrane Library literature databases up to June 2022. A total of seven studies were included, and quality assessment was performed for each included study using the Newcastle−Ottawa Quality Assessment Scale. Statistical analysis was performed on the extracted pooled clinical outcome data, and subgroup analyses were completed. Results: A total of 570 patients were included in the analysis. In pooled analysis, the final follow-up International Knee Documentation Committee (IKDC) score showed a significant increase (mean difference (MD), −32.82; 95% confidence interval (CI), −38.32 to −27.32; p < 0.00001) with significant heterogeneity (I2 = 93%, p < 0.00001) compared to the preoperative score. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at final follow-up were significantly decreased (MD, 30.73; 95% CI, 24.10−37.36; p < 0.00001) compared to the preoperative scores, with significant heterogeneity (I2 = 95%, p < 0.00001). The visual analog scale (VAS) score at final follow-up was significantly decreased (MD, 4.81; 95% CI, 3.17−6.46; p < 0.00001) compared to the preoperative score, with significant heterogeneity (I2 = 98%, p < 0.00001). Two studies evaluated the modified Magnetic Resonance Observation of Cartilage Repair Tissue (M-MOCART) score and confirmed sufficient improvement. In a study analyzing a group treated with bone marrow aspiration concentrate (BMAC), there was no significant difference in clinical outcome or M-MOCART score, and the post-treatment International Cartilage Repair Society (ICRS) grade increased. Conclusion: This analysis demonstrated the safety, efficacy, and quality of repaired cartilage following hUCB-MSC therapy. However, there was no clear difference in the comparison with BMAC. In the future, comparative studies with other stem cell therapies or cartilage repair procedures should be published to support the superior effect of hUCB-MSC therapy to improve treatment of cartilage defect or osteoarthritis.

The Hunt Is On! In Pursuit of the Ideal Stem Cell Population for Cartilage Regeneration

Cartilage injury and degeneration are hallmarks of osteoarthritis (OA), the most common joint disease. OA is a major contributor to pain, loss of function, and reduced quality of life. Over the last decade, considerable research efforts have focused on cell-based therapies, including several stem cell-derived approaches to reverse the cartilage alterations associated with OA. Although several tissue sources for deriving cell-based therapies have been identified, none of the resident stem cell populations have adequately fulfilled the promise of curing OA. Indeed, many cell products do not contain true stem cells. As well, issues with aggressive marketing efforts, combined with a lack of evidence regarding efficacy, lead the several national regulatory bodies to discontinue the use of stem cell therapy for OA until more robust evidence becomes available. A review of the evidence is timely to address the status of cell-based cartilage regeneration. The promise of stem cell therapy is not new and has been used successfully to treat non-arthritic diseases, such as hematopoietic and muscle disorders. These fields of regenerative therapy have the advantage of a considerable foundation of knowledge in the area of stem cell repair mechanisms, the role of the stem cell niche, and niche-supporting cells. This foundation is lacking in the field of cartilage repair. So, where should we look for the ideal stem cell to regenerate cartilage? It has recently been discovered that cartilage itself may contain a population of SC-like progenitors. Other potential tissues include stem cell-rich dental pulp and the adolescent growth plate, the latter of which contains chondrocyte progenitors essential for producing the cartilage scaffold needed for bone growth. In this article, we review the progress on stem cell therapies for arthritic disorders, focusing on the various stem cell populations previously used for cartilage regeneration, successful cases of stem cell therapies in muscle and hemopoietic disorders, some of the reasons why these other fields have been successful (i.e., "lessons learned" to be applied to OA stem cell therapy), and finally, novel potential sources of stem cells for regenerating damaged cartilage in vivo.

Extent of Preoperative Medial Meniscal Extrusion Influences Intermediate-Term Outcomes After Medial Opening-Wedge High Tibial Osteotomy

BACKGROUND

The purpose of the present study was to determine the relationship between preoperative medial meniscal extrusion, as classified according to magnetic resonance imaging (MRI), and medial opening-wedge high tibial osteotomy outcomes at intermediate-term follow-up.

METHODS

We reviewed the records for 212 patients who had undergone medial opening-wedge high tibial osteotomy for the treatment of medial compartment osteoarthritis between January 2009 and September 2014, with a minimum duration of follow-up of 5 years. Patients were divided into 2 groups according to the presence of pathologic medial meniscal extrusion (>3 mm). Moreover, patients were divided into 4 groups according to MRI Osteoarthritis Knee Score (MOAKS) criteria and relative medial meniscal extrusion values. Associations between the extent of preoperative medial meniscal extrusion and clinical outcomes over a mean duration of follow-up of 8.1 years were evaluated with use of Spearman rank correlation analysis. Regression analyses were performed to determine preoperative characteristics relevant to medial meniscal extrusion. Clinical outcomes were assessed with use of the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Tegner activity scale score.

RESULTS

Postoperative KOOS pain scores were significantly different in the pathologic and non-pathologic medial meniscal extrusion groups (69.9 ± 18.0 versus 79.2 ± 11.4, respectively; p < 0.001). Additionally, the degree of preoperative medial meniscal extrusion based on both classification methods and the postoperative KOOS pain score were significantly correlated (r = -0.404 and -0.364; p < 0.001). Despite the inferior clinical outcomes associated with greater preoperative medial meniscal extrusion, medial opening-wedge high tibial osteotomy was associated with significant improvement in all outcome measures between the preoperative and latest follow-up assessments (p < 0.001). Preoperative meniscal patterns, including horizontal flap, complex, and root tears (p = 0.001), and increased Kellgren-Lawrence grade (p < 0.001) were related to the severity of medial meniscal extrusion. The survival rate was 94.8% at a mean of 8.1 years, and survival was not associated with the grade of medial meniscal extrusion as assessed with either classification scheme.

CONCLUSIONS

At intermediate-term follow-up, greater preoperative medial meniscal extrusion was related to inferior postoperative clinical outcomes, specifically pain, after medial opening-wedge high tibial osteotomy. Despite the inferior results associated with preoperative medial meniscal extrusion, medial opening-wedge high tibial osteotomy was associated with a satisfactory survival rate after a mean of 8.1 years, regardless of the extent of medial meniscal extrusion.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Potential New Treatments for Knee OA: A Prospective Review of Registered Trials

We aimed to evaluate potential new treatments for knee osteoarthritis (OA). The National Institute of Health ClinicalTrials.gov database was searched for “Osteoarthritis, Knee”. We found 565 ongoing interventional studies with a total planned enrollment of 111,276 subjects. Ongoing studies for knee OA represent a very small fraction of the registered clinical trials, but they are over a quarter of all knee trials and over two thirds of all OA studies. The most researched topic was arthroplasty, with aspects such as implant design changes, cementless fixation, robotic guidance, pain management, and fast track recovery. Intraarticular injections focused on cell therapies with mesenchymal stem cells sourced from adipose tissue, bone marrow, or umbilical cord. We could see the introduction of the first disease modifying drugs with an impact on knee OA, as well as new procedures such as geniculate artery embolization and geniculate nerve ablation.

Intra-articular injection of orthobiologics in patients undergoing high tibial osteotomy for knee osteoarthritis is safe and effective - a systematic review

Purpose

To qualitatively evaluate the current evidence reporting outcomes of intra-articular injection of orthobiologics in patients undergoing high tibial osteotomy (HTO) for osteoarthritis of the knee.

Methods

A systematic search methodology of the PUBMED, EMBASE, and CINAHL databases was conducted in July 2021. The search workflow was in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The following inclusion criteria were adopted: clinical trials of any level of evidence, reporting outcomes following intra-articular injection of orthobiologics during high tibial osteotomy for knee osteoarthritis, with a minimum number of 10 patients treated. Duplicate data, studies on implanted orthobiologics and articles not written in English were excluded from this review.

Results

Eight studies were included in this review, with a total of 585 patients. Outcomes were discussed based on the types of orthobiologics used: (i) Platelet-Rich Plasma (PRP), (ii) Bone Marrow Aspirate Concentrate (BMAC), and (iii) Injected Mesenchymal Stem Cells (MSCs). Two studies utilised PRP, 4 studies utilised BMAC and 4 studies utilised injected MSCs.. Three studies provided Level II evidence and five studies provided Level III evidence. Statistically significant improvements in outcomes were documented in multiple trials, with few patients experiencing adverse events.

Conclusion

Intra-articular injection of orthobiologics in patients undergoing HTO is safe and effective with good outcomes reported. Due to the lack of high-level evidence, further research is required before this can be considered standard of care.

Level of evidence

III

Cell Sources for Cartilage Repair-Biological and Clinical Perspective

Cell-based therapy represents a promising treatment strategy for cartilage defects. Alone or in combination with scaffolds/biological signals, these strategies open many new avenues for cartilage tissue engineering. However, the choice of the optimal cell source is not that straightforward. Currently, various types of differentiated cells (articular and nasal chondrocytes) and stem cells (mesenchymal stem cells, induced pluripotent stem cells) are being researched to objectively assess their merits and disadvantages with respect to the ability to repair damaged articular cartilage. In this paper, we focus on the different cell types used in cartilage treatment, first from a biological scientist’s perspective and then from a clinician’s standpoint. We compare and analyze the advantages and disadvantages of these cell types and offer a potential outlook for future research and clinical application.