Arthroscopic Minced Cartilage Implantation (MCI): A Technical Note

[Autologous minced cartilage implantation for focal cartilage lesions of the humeral capitellum]

OBJECTIVE

The goal of minced cartilage implantation (MCI) is to restore an intact cartilage surface in focal osteochondral lesions of the humeral capitellum.

INDICATIONS

The indications for MCI are limited osteochondral lesions at the humeral capitellum, also at the head of the radius, with intact cartilage border as well as in situ or a completely detached fragment, and free joint bodies (grade II-grade V according to Hefti).

CONTRAINDICATIONS

Contraindications for MCI are already concomitant or associated cartilage damage as well as bilateral osteochondral lesions and insufficient available cartilage material.

SURGICAL TECHNIQUE

After diagnostic arthroscopy to detect possible concomitant pathologies and to exclude already corresponding cartilage lesions, the arthroscope is flipped posterolaterally over the high posterolateral portal and a second portal is created under visualization via the soft spot. Initially, debridement of the focal cartilage defect, assessment of the marginal zone, and/or salvage of free joint bodies. Using a smooth shaver and the filter provided, the partially or even completely detached cartilage fragment is unidirectionally fragmented under continuous suction. The remaining defect with a stable marginal zone is cleanly curetted, and the joint is completely dried. The fragmented cartilage collected in the filter is bonded to a membrane using autologous conditioned plasma (ACP) and then arthroscopically applied to the defect via a cannula, sealed using thrombin and fibrin.

POSTOPERATIVE MANAGEMENT

Postoperative immobilization in a cast for at least 24 h is required. Afterwards, free exercise of the joint is possible, but no loading should be maintained for 6 weeks. Return to sport after 3 months.

RESULTS

Good to very good clinical and MRI morphologic results are already evident in the short-term course. Prospective and retrospective multicenter studies are needed to evaluate future long-term results.

Autologous Minced Repair of Knee Cartilage Is Safely and Effectively Performed Using Arthroscopic Techniques

Articular cartilage defects in the knee are common and possess limited ability to inherently heal. Many of the surgical management options for cartilage repair that result in a hyaline or hyaline-like chondral surface have donor site morbidity, are resource intensive, are costly, and may require multiple surgeries. Autologous minced cartilage implantation is an encouraging, single-stage technique that can be safely and efficiently performed arthroscopically to address focal chondral defects in the knee. The limited morbidity and cost-effective nature of using autograft tissue has clear advantages, including an ability to treat patients at the time a clinically relevant defect is identified, increased availability of tissue, reduced patient morbidity with the use of an arthroscopic harvest technique, and the production of a hyaline cartilage repair product with active chondrocytes. Clinically, it has been demonstrated to be superior to microfracture. However, mincing technique may compromise cell viability. A recent porcine model investigation demonstrated that arthroscopic cartilage harvest using a shaver, contains a significantly lower median number of viable chondrocytes compared to open scalpel harvest, resulting in reduced proteoglycans, glycosaminoglycans, aggrecan, and COL2A1 expression, a result of fewer viable chondrocytes. The authors suggest that traditional open scalpel harvest results in a superior single-stage autologous minced cartilage transplantation product with more hyaline-like tissue compared to arthroscopic mincing techniques. However, the findings of the study regarding cell viability after arthroscopic harvest are in stark contrast to previous findings, including our prior work. Pending future research, it is our view that an arthroscopic single-stage autologous cartilage transplant is more reproducible, efficient, and of lower morbidity than open harvest, and we and others have shown the arthroscopic technique to be both safe and effective.

Comparison of Minced Cartilage Implantation with Autologous Chondrocyte Transplantation in an In Vitro Inflammation Model

The current gold standard to treat large cartilage defects is autologous chondrocyte transplantation (ACT). As a new surgical method of cartilage regeneration, minced cartilage implantation (MCI) is increasingly coming into focus. The aim of this study is to investigate the influence of chondrogenesis between isolated and cultured chondrocytes compared to cartilage chips in a standardized inflammation model with the proinflammatory cytokine TNFα. Articular chondrocytes from bovine cartilage were cultured according to the ACT method to passage 3 and transferred to spheroid culture. At the same time, cartilage was fragmented (<1 mm3) to produce cartilage chips. TNFα (20 ng/mL) was supplemented to simulate an inflammatory process. TNFα had a stronger influence on the passaged chondrocytes compared to the non-passaged ones, affecting gene expression profiles differently between isolated chondrocytes and cartilage chips. MCI showed less susceptibility to TNFα, with reduced IL-6 release and less impact on inflammation markers. Biochemical and histological analyses supported these findings, showing a greater negative influence of TNFα on the passaged pellet cultures compared to the unpassaged cells and MCI constructs. This study demonstrated the negative influence of TNFα on chondrogenesis in a chondrocyte spheroid culture and cartilage fragment model. Passaged chondrocytes are more sensitive to cytokine influences compared to non-passaged cells and chondrons. This suggests that MCI may have superior regeneration potential in osteoarthritic conditions compared to ACT. Further investigations are necessary for the translation of these findings into clinical practice.

Operative management of osteochondral lesions of the talus: 2024 recommendations of the working group 'clinical tissue regeneration' of the German Society of Orthopedics and Traumatology (DGOU)

The working group 'Clinical Tissue Regeneration' of the German Society of Orthopedics and Traumatology (DGOU) issues this paper with updating its guidelines. Literature was analyzed regarding different topics relevant to osteochondral lesions of the talus (OLT) treatment. This process concluded with a statement for each topic reflecting the best scientific evidence available with a grade of recommendation. All group members rated the statements to identify possible gaps between literature and current clinical practice. Fixation of a vital bony fragment should be considered in large fragments. In children with open physis, retrograde drilling seems to work better than in adults, but even there, the revision rate reaches 50%. The literature supports debridement with bone marrow stimulation (BMS) in lesions smaller than 1.0 cm² without bony defect. The additional use of a scaffold can be recommended in lesions larger than 1.0 cm². For other scaffolds besides AMIC®/Chondro-Gide®, there is only limited evidence. Systematic reviews report good to excellent clinical results in 87% of the patients after osteochondral transplantation (OCT), but donor site morbidity is of concern, reaching 16.9%. There is no evidence of any additional benefit from autologous chondrocyte implantation (ACI). Minced cartilage lacks any supporting data. Metallic resurfacing of OLT can only be recommended as a second-line treatment. A medial malleolar osteotomy has a minor effect on the clinical outcome compared to the many other factors influencing the clinical result.

Does AMIC® provide improvements at least two years after surgery for knee osteochondral lesions? A multicentre retrospective study of 101 patients

BACKGROUND

Osteochondral defects of the knee due to trauma or osteochondritis are associated with osteoarthritis in the medium term. Defects 2 to 8cm2 in size can be managed by autologous matrix-induced chondrogenesis (AMIC®), in which sub-chondral micro-fractures are created within the lesion and the defect is then covered by a matrix of type I and type III collagen to induce de novo cartilage formation. Although promising outcomes have been observed in small single-centre cohorts, the medium-term clinical and radiological effectiveness of AMIC® remains to be demonstrated in larger populations. The objective of this study was to evaluate outcomes of patients at least 2 years after AMIC® for knee osteochondral defects.

HYPOTHESIS

AMIC® is associated with clinical and radiological improvements after at least 2 years.

MATERIAL AND METHOD

This multicentre (16 centres), multisurgeon (18 senior orthopaedic surgeons), retrospective study included consecutive patients who underwent AMIC® with Chondro-Gide® membrane implantation between September 2011 and January 2020. The 36-item Short Form quality-of-life (SF-36) score, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) score were determined before the procedure and during follow-up. The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was assessed by magnetic resonance imaging 2 years after the procedure.

RESULTS

In total, 101 patients aged 12 to 60 years were included. Mean follow-up was 30 months. Mean defect size was 3.44cm2 (range, 2-8cm2). Significant improvements were documented in the SF-36 score, KOOS, and IKDC score. The mean MOCART score at 2 years was 75% (range, 20-100).

DISCUSSION

The AMIC® procedure was associated with significant improvements at 2.5 years in patients treated for knee osteochondral defects measuring 2 to 8cm2. This method seems to provide similar outcomes to those of other available methods with the advantages of single-step surgery and elimination of osteochondral graft donor-site complications.

LEVEL OF EVIDENCE

IV, retrospective observational cohort study.

Suitable characteristics in the selection of human allogeneic chondrocytes donors to increase the number of viable cells for cartilage repair

Autologous chondrocyte implantation has shown optimal long-term outcomes in the treatment of cartilage lesions. The challenge for a single-stage approach lies in obtaining sufficient number of cells with high viability. The answer could lie in supplementing or replacing them with allogenic chondrocytes coming from cadaveric donors. In the present work, we aimed to compare the number of viable cells isolated from cartilage of live and cadaveric donors and to determine the suitable characteristics of the best donors. A total of 65 samples from donors aged from 17 to 55 years, either women or men, were enrolled in this study (33 living vs. 32 cadaveric). The mean time of hours from death to processing samples in cadaveric donors was higher compared to live donors (64.3 ± 17.7 vs. 4.6±6.4). The number of isolated chondrocytes per gram of cartilage was higher in cadaveric donors (5.389 × 106 compared to 3.067 × 106 in living donors), whereas the average of cell viability was comparable in both groups (84.16% cadaveric, 87.8% alive). It is possible to obtain viable chondrocytes from cartilage harvested from cadaveric donors, reaching a similar cell number and viability to that obtained from the cartilage of living donors.

Autologous minced cartilage repair for chondral and osteochondral lesions of the knee joint demonstrates good postoperative outcomes and low reoperation rates at minimum five-year follow-up

PURPOSE

Minced cartilage is a one-step, autologous procedure with promising short-term results. The aim of the present study was to evaluate mid-term results in a patient cohort with chondral and osteochondral lesions in the knee joint treated with minced cartilage.

METHODS

From 2015 through 2016, a total of 34 consecutive patients were treated with a single-step, autologous minced cartilage for knee chondral and osteochondral lesions. Numeric analogue scale (NAS) for pain and knee function were obtained prior to surgery and at 12, 24 and 60 months postoperatively. Secondary outcomes, including Lysholm score, Tegner activity score, and the International Knee Documentation Committee (IKDC) score, were recorded at final follow-up. MRI examinations of patients with unplanned radiological follow-up were analysed using the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score.

RESULTS

A total of 28 patients (44.1% females, age at surgery: 29.5 ± 11.5 years) were available at a mean follow-up of 65.5 ± 4.1 months. Mean defect size was 3.5 ± 1.8 cm2. NAS for pain decreased from a median of 7 (range: 2-10) preoperatively to 2 (0-8) postoperatively. NAS knee function improved from a median of 7 (range: 2-10) to 3 (0-7) after five years, respectively. Satisfactory Lysholm (76.5 ± 12.5), IKDC (71.6 ± 14.8) and Tegner activity (4, range 3-9) scores were reported at final follow-up. Of all patients, 21(75%) and 19 (67.9%) reached or exceeded the PASS for the IKDC- and Lysholm score at final follow-up, respectively. The average overall MOCART 2.0 scores for all postoperatively performed MRIs (n = 23) was 62.3 ± 17.4. Four (14.2%) postoperative complications were directly linked to minced cartilage, one (3.5%) of which required revision surgery.

CONCLUSION

One-step, autologous minced cartilage repair of chondral and osteochondral lesions of the knee without the necessity for subchondral bone treatment demonstrated good patient-reported outcomes, low complication rates, and graft longevity at mid-term follow-up. Minced cartilage represents a viable treatment option to more traditional cartilage repair techniques even in mid-term.

LEVEL OF EVIDENCE

Level III.

Single-stage autologous cartilage repair results in positive patient-reported outcomes for chondral lesions of the knee: a systematic review

AIM

This article aims to perform a systematic review of the clinical literature regarding the efficacy of single-stage autologous cartilage repair.

METHODS

A systematic review of the literature was performed using PubMed, Scopus, Web of Science, and the Cochrane Library. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed.

RESULTS

Twelve studies were identified; however, due to overlapping patient cohorts, nine studies were included for data extraction and analysis. Six studies applied minced cartilage, while three studies utilized enzymatically processed cartilage. Two authorship groups described single-stage techniques that exclusively utilized cartilage from the debrided lesion rim, while the remaining groups either utilized healthy cartilage or combined healthy cartilage with cartilage debrided from lesion rim. Among the included techniques, scaffold augments were used in four studies, and three studies implemented bone autograft augmentation. When summarizing patient reported outcome measures for the included studies, single-stage autologous cartilage repair demonstrated an average improvement ranging from 18.7 ​± ​5.3 to 30.0 ​± ​8.0 amongst the Knee Injury and Osteoarthritis Outcome Scores subsections, 24.3 ​± ​10.5 for the International Knee Documentation Committee subjective score, and 41.0 ​± ​10.0 for Visual Analogue Scale-Pain.

CONCLUSION

Single-stage autologous cartilage repair is a promising technique with positive clinical data to date. The current study highlights the overall improvement in patient reported outcomes after repair for chondral defects to the knee with average follow-up ranging from 12 to 201 months and also the heterogeneity and variability of the single-stage surgical technique. Further discussion on the standardization of practices for a cost-effective single-stage augmented autologous cartilage technique is needed. In the future, a well-designed randomized controlled trial is needed to explore the efficacy of this therapeutic modality relative to established intervention.

LEVEL OF EVIDENCE

Systematic review; Level IV.

Treatment of Chondral Lesions in the Knee

Articular cartilage injuries are common and lead to early joint deterioration and osteoarthritis. Articular cartilage repair techniques aim at forming a cartilaginous neo-tissue to support the articular load and prevent progressive degeneration. Several techniques are available for this purpose, such as microfracture and chondrocyte transplantation. However, the procedural outcome is often fibrocartilage, which does not have the same mechanical resistance as cartilaginous tissue. Procedures with autologous osteochondral graft have a morbidity risk, and tissue availability limits their use. As such, larger lesions undergo osteochondral transplantation using fresh or frozen grafts. New techniques using minced or particulate cartilage fragments or mesenchymal stem cells are promising. This paper aims to update the procedures for treating chondral lesions of the knee.

The Influence of Arthroscopic Shaver Mincing and Platelet-Rich Plasma on Chondrocytes of Intraoperatively Harvested Human Cartilage

BACKGROUND

Minced cartilage implantation (MCI) has seen a renaissance in recent years. In this evolved technique, human articular cartilage is harvested with an arthroscopic shaver, augmented with platelet-rich plasma (PRP), and implanted with autologous thrombin. This modified technique combines the possibility of cell-based surgical cartilage repair with a minimally invasive autologous 1-step procedure. However, evidence on cell survival and preserved function after shaver-based mincing and PRP supplementation is limited.

PURPOSE

To evaluate the effects of arthroscopic shaver mincing and augmentation with PRP on human cartilage tissue.

STUDY DESIGN

Controlled laboratory study.

METHODS

Standardized samples were taken from 12 donors during autologous MCI. A comparison of cell outgrowth, cell viability, proliferation capacity, and ability to produce extracellular matrix-specific proteoglycans after chondrogenic redifferentiation was made between cartilage taken by curettage from the border of the cartilage defect, cartilage tissue minced by an arthroscopic shaver, and cartilage tissue minced by an arthroscopic shaver that was additionally augmented with autologous PRP.

RESULTS

There was no difference between all 3 groups in terms of cell outgrowth or proliferation capacity. Metabolic activity relative to the cell number of chondrocytes isolated from shaver-minced cartilage was higher compared with chondrocytes isolated from cartilage that was derived by curettage or shaver-minced cartilage that was augmented with PRP. After chondrogenic stimulation, the normalized proteoglycan content was higher in spheroids of cells derived from shaver-minced cartilage augmented with PRP than in spheroids of cells derived from curettage. A high correlation of cell outgrowth, proliferation capacity, and viability between isolated cells from all 3 groups taken from an individual donor was observed.

CONCLUSION

Chondrocytes isolated from human cartilage tissue that was harvested and minced with an arthroscopic shaver remained viable and proliferative. The augmentation of shaver-minced cartilage with PRP led to the enhanced proteoglycan production of chondrogenic spheroids in vitro, pointing toward the development of a cartilage-specific extracellular matrix. This in vitro study yields promising results regarding the use of an arthroscopic shaver and augmentation with PRP in the context of MCI.

CLINICAL RELEVANCE

Knowledge that shaver mincing and augmentation with PRP are feasible for processing articular cartilage during MCI is highly relevant for surgical cartilage repair.

Retrograde "Sandwich" Technique and Implantation of Minced Cartilage in a Hyaluronic Acid Scaffold for Deep Osteochondral Knee Lesions

The management of deep osteochondral lesions is a subject of great controversy. Despite multiple studies and research efforts, it has not been possible to establish an ideal technique for their treatment. The main goal of all available treatments is to avoid the progress toward early osteoarthritis. Hence, this article will present a one-step technique for the handling of osteochondral lesions with a depth equal to or greater than 5 mm, with retrograde subchondral bone grafting to reconstruct the subchondral bone, seeking the greatest possible preservation of the subchondral plate, and implantation of autologous minced cartilage plus a hyaluronic acid-based scaffold (HyaloFast; Anika Therapeutics) under arthroscopic surgery.

Empfehlungen der AG Klinische Geweberegeneration zur Behandlung von Knorpelschäden am Kniegelenk

The Working Group of the German Orthopedic and Trauma Society (DGOU) on Tissue Regeneration has published recommendations on the indication of different surgical approaches for treatment of full-thickness cartilage defects in the knee joint in 2004, 2013 and 2016. Based upon new scientific knowledge and new developments, this recommendation is an update based upon the best clinical evidence available. In addition to prospective randomised controlled clinical trials, this also includes studies with a lower level of evidence. In the absence of evidence, the decision is based on a consensus process within the members of the working group.The principle of making decision dependent on defect size has not been changed in the new recommendation either. The indication for arthroscopic microfracturing has been reduced up to a defect size of 2 cm² maximum, while autologous chondrocyte implantation is the method of choice for larger cartilage defects. Additionally, matrix-augmented bone marrow stimulation (mBMS) has been included in the recommendation for defects ranging from 1 to 4.5 cm². For the treatment of smaller osteochondral defects, in addition to osteochondral transplantation (OCT), mBMS is also recommended. For larger defects, matrix-augmented autologous chondrocyte implantation (mACI/mACT) in combination with augmentation of the subchondral bone is recommended.

Biologic principles of minced cartilage implantation: a narrative review

Cartilage tissue has a very limited ability to regenerate. Symptomatic cartilage lesions are currently treated by various cartilage repair techniques. Multiple treatment techniques have been proposed in the last 30 years. Nevertheless, no single technique is accepted as a gold standard. Minced cartilage implantation is a newer technique that has garnered increasing attention. This procedure is attractive because it is autologous, can be performed in a single surgery, and is therefore given it is cost-effective. This narrative review provides an overview of the biological potential of current cartilage regenerative repair techniques with a focus on the translational evidence of minced cartilage implantation.

Autologous Minced Cartilage Implantation for Arthroscopic One-Stage Treatment of Osteochondritis Dissecans of the Elbow

This Technical Note describes the full arthroscopic one-stage treatment of high-grade osteochondritis dissecans of the humeral capitellum of the elbow joint by means of minced cartilage implantation.

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.

Minced Cartilage Procedure for One-Stage Arthroscopic Repair of Chondral Defects at the Glenohumeral Joint

Chondral defects of the glenohumeral joint are common but still remain a diagnostic and management challenge. Whereas arthroplasty is a reasonable treatment option in the elderly and low-demand population, joint preservation should be aimed for the remaining patients. For larger defects the current gold standard of treatment is autologous chondrocyte implantation. However, disadvantages such as high cost, the restriction in availability of specialized laboratories, and the 2-stage surgical design need to be accounted for if choosing this option. Showing first good clinical results for the knee joint, minced cartilage implantation is moreover a cost-effective procedure bringing autologous cartilage chips harvested from the defect walls and bringing them into the area of damage in a single-step open or arthroscopic approach. We describe an arthroscopic strategy of this technique to treat chondral defects at the glenohumeral joint.

Reconstruction of Large Osteochondral Lesions in the Knee: Focus on Fixation Techniques

Large (>3 cm²), focal osteochondral lesions (OCL) may result in poor functional outcomes and early secondary osteoarthritis of the knee. The surgical management of these OCL remains challenging. The treatment strategy must be tailored to various aspects, including lesion-specific (e.g., size, location, chronicity), joint-specific (e.g., instability, limb alignment, meniscal status), and patient-specific factors (e.g., age, activity level, comorbidities). Simple chondroplasty and bone marrow stimulation (BMS) techniques should be reserved for smaller lesions, as they only realize midterm clinical benefits, related to inferior wear characteristics of the induced fibrocartilage (type I collagen). Therefore, much attention has been focused on surgical restoration with hyaline cartilage (type II collagen), based on chondrocyte transplantation and matrix-assisted autologous chondrocyte implantation (MACI). Limited graft availability, staged procedures (MACI), and high treatment costs are limitations of these techniques. However, acute traumatic OCL of the femoral condyles and patellofemoral joint may also be suitable for preservation by surgical fixation. Early detection of the fragment facilitates primary repair with internal fixation. The surgical repair of the articular surface may offer promising clinical and cost-effective benefits as a first-line therapy but remains under-investigated and potentially under-utilized. As a unique characteristic, the fixation technique allows the anatomic restoration of the hyaline articular surface with native cartilage and the repair of the subchondral bone. In this manuscript, we present a case series of large OCL around the knee that were preserved by surgical fixation. Furthermore, various implants and techniques reported for this procedure are reviewed.