Long-term clinical and radiological assessment of untreated severe cartilage damage in the knee: a natural history study

Focal resurfacing of the knee - A systematic review and meta-analysis

PURPOSE

In order to assess the published validity of focal resurfacing of the knee, a systematic review and meta-analysis were conducted to (i) evaluate revision rates and implant survival of focal resurfacing of the knee; (ii) explore surgical complications; and (iii) evaluate patient reported clinical outcome measures.

METHODS

PubMED, Cochrane Library and Medline databases were searched by 2 independent reviewers in February 2022 for prospective and retrospective cohort studies evaluating any of the following implant types: HemiCAP®, UniCAP®, Episealer® or BioBoly®. Data on incidence of revision, complications and various patient reported outcome measures, such as Knee Society Score (KSS) or Knee Injury and Osteoarthritis Outcome Score (KOOS) was sourced.

RESULTS

A total of 24 published studies were identified with a total of 1465 enrolled patients. A revision rate of 12.97% over a 5.9 year weighted mean follow-up period was observed across all implant types. However, in one series a Kaplan-Meir survival as high as 92.6% at a 10-year follow-up period was noted. A statistically significant improvement was documented across multiple subjective clinical outcomes scores, for example a mean 4.56 point improvement of the VAS (0-10) pain score. The Kellgren-Lawrence score was used to evaluate the radiological progression of osteoarthritis and showed a small significant reduction in all anatomical locations, hence not supporting the hypothesis that focal femoral implants can lead to the progression of osteoarthritis in the affected compartment. There was a low reported incidence of post-operative complications such as aseptic loosening or deep wound infection.

CONCLUSIONS

Focal femoral resurfacing appears to be a viable treatment option for focal symptomatic chondral lesions in patients beyond biological reconstruction, with low revision rates and high patient satisfaction especially at short and medium length follow-up.

The Large Focal Isolated Chondral Lesion

Focal chondral defects (FCDs) of the knee can be a debilitating condition that can clinically translate into pain and dysfunction in young patients with high activity demands. Both the understanding of the etiology of FCDs and the surgical management of these chondral defects has exponentially grown in recent years. This is reflected by the number of surgical procedures performed for FCDs, which is now approximately 200,000 annually. This fact is also apparent in the wide variety of available surgical approaches to FCDs. Although simple arthroscopic debridement or microfracture are usually the first line of treatment for smaller lesions, chondral lesions that involve a larger area or depth require restorative procedures such as osteochondral allograft transplantation or other cell-based techniques. Given the prevalence of FCDs and the increased attention on treating these lesions, a comprehensive understanding of management from diagnosis to rehabilitation is imperative for the treating surgeon. This narrative review aims to describe current concepts in the treatment of large FCDs through providing an algorithmic approach to selecting interventions to address these lesions as well as the reported outcomes in the literature.

Matrix-assisted autologous chondrocyte transplantation for treatment of focal chondral lesions in the knee: the Hospital Israelita Albert Einstein experience

Objective

Phase 1 clinical trial to determine feasibility, safety, and efficacy of a new advanced cell therapy product for treatment of knee articular cartilage injuries.

Methods

Three participants with knee focal chondral lesions were included, with no signs of osteoarthritis. Chondrocytes were obtained through knee arthroscopy, cultured in collagen membrane for 3 weeks at the laboratory, subjected to tests to release the cell therapy product, and implanted. All patients underwent a specific 3-month rehabilitation protocol, followed by assessments using functional and imaging scales. The main outcome was the incidence of severe adverse events.

Results

Three participants were included and completed the 2-year follow-up. There was one severe adverse event, venous thrombosis of distal leg veins, which was no associated with therapy, was treated and left no sequelae. The clinical and radiological scales showed improvement in the three cases.

Conclusion

The preliminary results, obtained with the described methodology, allow concluding that this product of advanced cell therapy is safe and feasible. ReBEC platform registration number: RBR-6fgy76

Modulation of Inflamed Synovium Improves Migration of Mesenchymal Stromal Cells in Vitro Through Anti-Inflammatory Macrophages

OBJECTIVE

Inflammation is known to negatively affect cartilage repair. However, it is unclear how inflammation influences the migration of mesenchymal stromal cells (MSCs) from the underlying bone marrow into the defect. We therefore aimed to investigate how synovial inflammation influences MSC migration, and whether modulation of inflammation with triamcinolone acetonide (TAA) may influence migration.

DESIGN

Inflamed human osteoarthritic synovium, M(IFNγ+TNFα) pro-inflammatory macrophages, M(IL4) repair macrophages, M(IL10) anti-inflammatory macrophages, or synovial fibroblasts were cultured with/without TAA. Conditioned medium (CM) was harvested after 24 hours, and the effect on MSC migration was studied using a Boyden chamber assay. Inflammation was evaluated with gene expression and flow cytometry analysis.

RESULTS

Synovium CM increased MSC migration. Modulation of synovial inflammation with TAA further increased migration 1.5-fold (P < 0.01). TAA significantly decreased TNFA, IL1B, and IL6 gene expression in synovium explants and increased CD163, a gene associated with anti-inflammatory macrophages. TAA treatment decreased the percentage of CD14+/CD80+ and CD14+/CD86+ pro-inflammatory macrophages and increased the percentage of CD14+/CD163+ anti-inflammatory macrophages in synovium explants. Interestingly, MSC migration was specifically enhanced by medium conditioned by M(IL4) macrophages and by M(IL10) macrophages treated with TAA, and unaffected by CM from M(IFNγ+TNFα) macrophages and synovial fibroblasts.

CONCLUSION

Macrophages secrete factors that stimulate the migration of MSCs. Modulation with TAA increased specifically the ability of anti-inflammatory macrophages to stimulate migration, indicating that they play an important role in secreting factors to attract MSCs. Modulating inflammation and thereby improving migration could be used in approaches based on endogenous repair of full-thickness cartilage defects.

Ultrasound-Based Quantification of Cartilage Damage After In Vivo Articulation With Metal Implants

OBJECTIVE

This study aims to evaluate the applicability of the ultrasound roughness index (URI) for quantitative assessment of cartilage quality ex vivo (post-mortem), after 6 months of in vivo articulation with a Focal Knee Resurfacing Implant (FKRI).

DESIGN

Goats received a metal FKRI (n = 8) or sham surgery (n = 8) in the medial femoral condyles. After 6 months animals were sacrificed, tibial plateaus were stained with Indian ink, and macroscopic scoring of the plateaus was performed based on the ink staining. The URI was calculated from high-frequency ultrasound images at several sections, covering both areas that articulated with the implant and non-articulating areas. Cartilage quality at the most damaged medial location was evaluated with a Modified Mankin Score (MMS).

RESULTS

The URI was significantly higher in the FKRI-articulating than in the sham plateaus at medial articulating sections, but not at sections that were not in direct contact with the implant, for example, under the meniscus. The mean macroscopic score and MMS were significantly higher in the FKRI-articulating group than in the sham group (P=0.035, P<0.001, respectively). Correlation coefficients between URI and macroscopic score were significant in medial areas that articulated with the implant. A significant correlation between URI and MMS was found at the most damaged medial location (ρ=0.72,P=0.0024).

CONCLUSIONS

This study demonstrates the potential of URI to evaluate cartilage roughness and altered surface morphology after in vivo articulation with a metal FKRI, rendering it a promising future tool for quantitative follow-up assessment of cartilage quality.

Editorial Commentary: Third-Generation Autologous Chondrocyte Implantation-Are Cells Seeded Onto the Scaffold Itself in It for the Long Run?

Autologous chondrocyte implantation (ACI) is an increasingly performed procedure, with rapidly evolving technology. First-generation ACI used a periosteal patch, leading to the second generation, in which a type I-type III collagen membrane is used to cover the autologous chondrocytes, and ultimately the third generation, in which autologous chondrocytes are seeded onto the scaffold itself. As third-generation, scaffold-based ACI techniques are becoming more widely available, interest in the long-term clinical and radiographic outcomes continues to grow, especially given the high costs associated with these procedures. Several studies have now shown persistently improved clinical outcomes at long-term follow-up, which support the increasing utilization of third-generation ACI techniques. However, it is important to continue to develop our understanding of the limitations of and expectations with third-generation ACI, particularly regarding reoperation, as well as to continue to design high-quality long-term studies that can evaluate differences in technology.

Therapeutic Potential of Dental Pulp Stem Cells and Leukocyte- and Platelet-Rich Fibrin for Osteoarthritis

Osteoarthritis (OA) is a degenerative and inflammatory joint disorder with cartilage loss. Dental pulp stem cells (DPSCs) can undergo chondrogenic differentiation and secrete growth factors associated with tissue repair and immunomodulation. Leukocyte- and platelet-rich fibrin (L-PRF) emerges in regenerative medicine because of its growth factor content and fibrin matrix. This study evaluates the therapeutic application of DPSCs and L-PRF in OA via immunomodulation and cartilage regeneration. Chondrogenic differentiation of DPSCs, with or without L-PRF exudate (ex) and conditioned medium (CM), and of bone marrow-mesenchymal stem cells was compared. These cells showed differential chondrogenesis. L-PRF was unable to increase cartilage-associated components. Immature murine articular chondrocytes (iMACs) were cultured with L-PRF ex, L-PRF CM, or DPSC CM. L-PRF CM had pro-survival and proliferative effects on unstimulated and cytokine-stimulated iMACs. L-PRF CM stimulated the release of IL-6 and PGE2, and increased MMP-13, TIMP-1 and IL-6 mRNA levels in cytokine-stimulated iMACs. DPSC CM increased the survival and proliferation of unstimulated iMACs. In cytokine-stimulated iMACs, DPSC CM increased TIMP-1 gene expression, whereas it inhibited nitrite release in 3D culture. We showed promising effects of DPSCs in an in vitro OA model, as they undergo chondrogenesis in vitro, stimulate the survival of chondrocytes and have immunomodulatory effects.

Optimization of TGF-β1-transduced chondrocytes for cartilage regeneration in a 3D printed knee joint model

A cell therapy product of transforming growth factor (TGF)-β1-transduced chondrocytes has been commercialized to treat osteoarthritis of the knee via intra-articular injection. The need for arthroscopic application of the cells to simultaneously treat intra-articular pathologies of knee osteoarthritis is increasingly urgent. The purpose of this study was to optimize TGF-β1-transduced chondrocytes for arthroscopic application. The optimal composition of chondrocytes and thrombin was initially determined by measuring the consolidation time of a diverse ratio of chondrocytes and thrombin mixed with 1 ml of fibrinogen. The consolidation time of the diverse ratio of fibrinogen and atelocollagen mixed with the determined optimal ratio of chondrocytes and thrombin was evaluated. The mixture of the determined optimal ratio of TGF-β1-transduced chondrocytes, atelocollagen, fibrinogen, and thrombin was applied to the cartilage defect of the 3D printed knee joint model arthroscopically. The status of the mixture in the defect was then evaluated. Chondrogenic activities of TGF-β1-transduced chondrocytes mixed with atelocollagen were evaluated. The determined ratio of TGF-β1-transduced chondrocytes to thrombin was 8:2 and that of fibrin to atelocollagen was also 8:2. Excellent maintenance of conformation of the mixture of TGF-β1-transduced chondrocytes, atelocollagen, fibrinogen, and thrombin in the cartilage defect of the 3D printed knee joint model was observed arthroscopically. Increased chondrogenic activities were observed in the group of TGF-β1-transduced chondrocytes mixed with atelocollagen. TGF-β1-transduced chondrocytes can be applied arthroscopically to treat cartilage defects of the knee at an optimized mixing ratio of atelocollagen, fibrinogen, and thrombin.

Do Focal Chondral Defects of the Knee Increase the Risk for Progression to Osteoarthritis? A Review of the Literature

Background:

Focal chondral defects (FCDs) of the knee are believed to contribute to the development of osteoarthritis (OA), resulting in pain and dysfunction.

Purpose:

To investigate whether untreated FCDs of the knee progress to radiographically evident OA over time.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

A literature review was performed by searching the PubMed, Embase, and Cochrane Library databases to locate studies evaluating clinical and/or radiological outcomes of patients with FCDs that were diagnosed by arthroscopic surgery or magnetic resonance imaging (MRI) and were left untreated with a minimum 2-year follow-up. Additionally, studies were included if there was a radiographic assessment of OA. Search terms used were “knee,” “focal,” “isolated,” “chondral,” “cartilage,” and “osteoarthritis.” Studies were evaluated based on clinical/radiological outcomes and OA risk factors. The study methodology was assessed using the modified Coleman Methodology Score.

Results:

Eight studies comprising 1425 knees met the inclusion criteria. All studies were of level 3 evidence. The risk of incident cartilage damage (enlargement of original FCDs or incidence of additional FCDs) at latest follow-up was assessed in 3 studies, while 1 study only reported the incidence of cartilage damage at follow-up. All 4 studies noted an increased progression of cartilage damage at follow-up. The progression of cartilage damage was most commonly seen in the patellofemoral joint and medial femoral condyle but was not associated with the development of knee OA based on the Kellgren-Lawrence grade. MRI of the FCDs revealed increased water content, cartilage deterioration, and proteoglycan loss within the medial and lateral compartments.

Conclusion:

Patients with untreated FCDs of the knee joint are more likely to experience a progression of cartilage damage, although the studies included in this review did not demonstrate the development of radiographically evident OA within 2 years of follow-up.

Functional outcomes after patellar autologous osteochondral transplantation

PURPOSE

The aim of the present study was to assess clinical evaluation of patients who underwent autologous osteochondral transplantation of the patella.

METHODS

This prospective study assessed outcomes of 20 patients who underwent patellar autologous osteochondral transplantation at four time-points: preoperatively, 3 days, 6 months, and 2 years after surgery. The following outcomes were assessed at each time-point: pain (VAS), gait, swelling, trophic status, muscle strength, patellar mobility, and range of motion. The Tegner scale was also applied for each time-point.

RESULTS

All parameters improved, except for patellar mobility, which did not show any change. Pain score decreased from 7.1 (SD 2.3) to 2.4 (SD 2.6) at the 2-year assessment; limping decreased from 70 % before surgery to 15 % 2 years later; swelling scores decreased from an average of 1.8 (SD 0.8) 3 days after surgery to 0.5 (SD 0.7) at the 2-year assessment; muscle strength increased from 3.9 (SD 0.8) to 4.7 (SD 0.7) points at final follow-up; and the range of motion increased from 84 (SD 16.2) to 132 (SD 10.7) degrees 2 years later. Tegner score before surgery ranged from 0 to 5, and after 2 years, it ranged from 5 to 9.

CONCLUSION

Autologous osteochondral transplantation for the treatment of patellar chondral lesion was associated with significant improvement in pain, gait, swelling, and range of motion 2 years after surgery, achieving scores similar to uninjured knees. Most of them were able to return to sports activity after 6 months (recreational level) and 2 years (competitive level).

LEVEL OF EVIDENCE

IV.

Effect of Human Adipose Tissue Mesenchymal Stem Cells on the Regeneration of Ovine Articular Cartilage

Cell therapy is a promising approach to improve cartilage healing. Adipose tissue is an abundant and readily accessible cell source. Previous studies have demonstrated good cartilage repair results with adipose tissue mesenchymal stem cells in small animal experiments. This study aimed to examine these cells in a large animal model. Thirty knees of adult sheep were randomly allocated to three treatment groups: CELLS (scaffold seeded with human adipose tissue mesenchymal stem cells), SCAFFOLD (scaffold without cells), or EMPTY (untreated lesions). A partial thickness defect was created in the medial femoral condyle. After six months, the knees were examined according to an adaptation of the International Cartilage Repair Society (ICRS 1) score, in addition to a new Partial Thickness Model scale and the ICRS macroscopic score. All of the animals completed the follow-up period. The CELLS group presented with the highest ICRS 1 score (8.3 ± 3.1), followed by the SCAFFOLD group (5.6 ± 2.2) and the EMPTY group (5.2 ± 2.4) (p = 0.033). Other scores were not significantly different. These results suggest that human adipose tissue mesenchymal stem cells promoted satisfactory cartilage repair in the ovine model.

Matrix-Applied Characterized Autologous Cultured Chondrocytes Versus Microfracture: Two-Year Follow-up of a Prospective Randomized Trial

BACKGROUND

Randomized controlled trials studying the efficacy and safety of matrix-applied characterized autologous cultured chondrocytes (MACI) versus microfracture (MFX) for treating cartilage defects are limited.

PURPOSE

To compare the clinical efficacy and safety of MACI versus MFX in the treatment of patients with symptomatic cartilage defects of the knee.

STUDY DESIGN

Randomized controlled clinical trial; Level of evidence, 1.

METHODS

Patients enrolled in the SUMMIT (Demonstrate the Superiority of MACI implant to Microfracture Treatment) trial had ≥1 symptomatic focal cartilage defect (Outerbridge grade III or IV; ≥3 cm(2)) of the femoral condyles or trochlea, with a baseline Knee Injury and Osteoarthritis Outcome Score (KOOS) pain value <55. The co-primary efficacy endpoint was the change in the KOOS pain and function subscores from baseline to 2 years. Histological evaluation and magnetic resonance imaging (MRI) assessments of structural repair tissue, treatment failure, the remaining 3 KOOS subscales, and safety were also assessed.

RESULTS

Of the 144 patients treated, 137 (95%) completed the 2-year assessment. Patients had a mean age of 33.8 years and a mean lesion size of 4.8 cm(2). The mean KOOS pain and function subscores from baseline to 2 years were significantly more improved with MACI than with MFX (pain: MACI, 37.0 to 82.5 vs MFX, 35.5 to 70.9; function: MACI, 14.9 to 60.9 vs MFX, 12.6 to 48.7; P = .001). A significant improvement in scores was also observed on the KOOS subscales of activities of daily living (MACI, 43.5 to 87.2 vs MFX, 42.6 to 75.8; P < .001), knee-related quality of life (MACI, 18.8 to 56.2 vs MFX, 17.2 to 47.3; P = .029), and other symptoms (MACI, 48.3 to 83.7 vs MFX, 44.4 to 72.2; P < .001) for patients treated with MACI compared with MFX. Repair tissue quality was good as assessed by histology/MRI, but no difference was shown between treatments. A low number of treatment failures (nonresponders: MACI, 12.5% vs MFX, 31.9%; P = .016) and no unexpected safety findings were reported.

CONCLUSION

The treatment of symptomatic cartilage knee defects ≥3 cm(2) in size using MACI was clinically and statistically significantly better than with MFX, with similar structural repair tissue and safety, in this heterogeneous patient population. Moreover, MACI offers a more efficacious alternative than MFX with a similar safety profile for the treatment of symptomatic articular cartilage defects of the knee.

Imaging of cartilage and osteochondral injuries: a case-based review

Current high-field magnetic resonance imaging (MRI) techniques provide a sensitive and reliable diagnostic tool for the evaluation of cartilage and osteochondral injury. This article summarizes technical factors for optimal MRI evaluation of articular cartilage of the knee. There is emphasis on the important correlation of the MRI signal to the structure of the type II collagen matrix in normal cartilage, with an understanding that alterations in this signal pattern can be an important sign of cartilage injury. Finally, specific patterns of cartilage injury and application of MRI in evaluating cartilage repair are illustrated through a series of selected cases.

Biomechanical considerations in the pathogenesis of osteoarthritis of the knee

Osteoarthritis is the most common joint disease and a major cause of disability. The knee is the large joint most affected. While chronological age is the single most important risk factor of osteoarthritis, the pathogenesis of knee osteoarthritis in the young patient is predominantly related to an unfavorable biomechanical environment at the joint. This results in mechanical demand that exceeds the ability of a joint to repair and maintain itself, predisposing the articular cartilage to premature degeneration. This review examines the available basic science, preclinical and clinical evidence regarding several such unfavorable biomechanical conditions about the knee: malalignment, loss of meniscal tissue, cartilage defects and joint instability or laxity. Level of evidence IV.

General principles for the regeneration of bone and cartilage

For the regeneration of bone and cartilage, mesenchymal stem cells are currently used invitro and in-vivo. For bone, the existence of viable cells, scaffolds, mechanical environment, growth factors and vascularization are of paramount importance. Mesenchymal stem cells can be harvested from the bone marrow using minimally invasive techniques. Centrifugation can increase the number of transplanted cells per volume. The use of cell therapy is under current clinical investigation and the benefit from these systems has to be proven in level I studies. For cartilage, current techniques recruiting stem cells from the subchondral bone have been demonstrated to be nearly as effective as autologous chondrocyte transplantation, requiring less invasive surgery. The efficacy of mesenchymal stem cell concentrates remains to be proven. There is high potential for tissue engineered joint surfaces to become an option for joint surface defects and degeneration.

Staging and comorbidities

Articular cartilage lesions of the distal femur and patella are common. To provide an accurate diagnosis of a clinically symptomatic cartilage lesion and subsequent appropriate planning for potential treatment options, a proper staging is required. This includes clinical exam, radiographic imaging as well as arthroscopy. Once the staging is completed, other comorbidities may need to be addressed that may require additional surgical procedures. These can either be planned as staged procedures or concomitantly with a cartilage repair procedure. This article will discuss this staging and evaluation process in depth to serve as a guideline to the orthopaedic surgeon engaged in the treatment of cartilage defects in patients with early posttraumatic osteoarthritis (OA).

Stem cell therapy for articular cartilage defects

BACKGROUND

Stem cells are easily accessible and have great potential for healing articular cartilage defects. These features make stem cell therapy an appealing approach for treating severely impaired joint function.

SOURCES OF DATA

Clinical and basic research articles and literature reviews.

AREAS OF AGREEMENT

Stem cells possess the potential to build articular cartilage. Malalignment and instability corrections and proper rehabilitation are crucial prerequisites for surgical procedures involving stem cell therapy. Smoking reduces the result.

AREAS OF CONTROVERSY

Ethical concerns remain unresolved. No standards are established for inducing stem cell potential, optimizing culturing media or harvesting. The risk of failure has not been determined.

GROWING POINTS

Surgical scaffolds can improve results. Care givers should focus on re-educating patients. Improved funding is needed for developing the therapy.

AREAS TIMELY FOR DEVELOPING RESEARCH

Define guidelines for stem cell therapy and demonstrate effectiveness.