Response of Articular Cartilage to Hyperosmolar Stress: Report of an Ex Vivo Injury Model.

BACKGROUND: Physiological 0.9% saline is commonly used as an irrigation fluid in modern arthroscopy. There is a growing body of evidence that a hyperosmolar saline solution has chondroprotective effects, especially if iatrogenic injury occurs. PURPOSE: To (1) corroborate the superiority of a hyperosmolar saline solution regarding chondrocyte survival after mechanical injury and (2) observe the modulatory response of articular cartilage to osmotic stress and injury. STUDY DESIGN: Controlled laboratory study. METHODS: Osteochondral explants were isolated from bovine stifle joints and exposed to either 0.9% saline (308 mOsm) or hyperosmolar saline (600 mOsm) and then damaged with a sharp dermatome blade to attain a confined full-thickness cartilage injury site, incubated in the same fluids for another 3 hours, and transferred to chondropermissive medium for further culture for 1 week. Chondrocyte survival was assessed by confocal imaging, while the cellular response was evaluated over 1 week by relative gene expression for apoptotic and inflammatory markers and mediator release into the medium. RESULTS: The full-thickness cartilage cut resulted in a confined zone of cell death that mainly affected superficial zone chondrocytes. Injured samples that were exposed to hyperosmolar saline showed less expansion of cell death in both the axial (P < .007) and the coronal (P < .004) plane. There was no progression of cell death during the following week of culture. Histological assessment revealed an intact cartilage matrix and normal chondrocyte morphology. Inflammatory and proapoptotic genes were upregulated on the first days postexposure with a notable downregulation toward day 7. Mediator release into the medium was concentrated on day 3. CONCLUSION: This in vitro cartilage injury model provides further evidence for the chondroprotective effect of a hyperosmolar saline irrigation fluid, as well as novel data on the capability of articular cartilage to quickly regain joint homeostasis after osmotic stress and injury. CLINICAL RELEVANCE: Raising the osmolarity of an irrigating solution may be a simple and safe strategy to protect articular cartilage during arthroscopic surgery.

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.

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.

The Validity of Motion Capture Analysis System against the Gold Standard Long-Standing Radiography in the Measurement of Lower Extremity Alignment.

Motion capture analysis (MCA) has the advantage of providing a static and dynamic leg axis analysis without radiation. Nevertheless, there is a lack of evidence regarding the accuracy of this technique. To test whether mechanical femorotibial axis angle (MAA) measurement recorded with a non-invasive MCA system is equal to the gold standard static long-standing full-leg radiographs (LSX) and if the degree of malalignment or other parameters (BMI, body mass, height, age) influence the accuracy, a total of 102 consecutive patients were examined using LSX and MCA. Static as well as all gait motion phases at 3 km/h were analyzed regarding the difference between the two angles. There was no statistical difference for MAA between LSX (MAArad) and MCA (MAAstat) (p = 0.091). There was a strong correlation (rs = 0.858, p < 0.001) between the two methods. The highest accuracy was detected for values of standing MCA. Also, the gait MCA values showed strong correlation with LSX but weaker correlation compared to standing MCA (initial swing rs = 0.549; terminal stance rs = 0.815; p < 0.001). BMI, body mass, and height did not influence the accuracy of MCA. MCA enables frontal alignment analysis with high accuracy and without the side effect of radiation.

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.

Triple Hybrid Tibial Anterior Cruciate Ligament Graft Fixation.

Optimal graft fixation in anterior cruciate ligament reconstruction is critical. Several direct and indirect methods of graft fixation exist, each with advantages and disadvantages. This Technical Note describes a tibial hybrid anterior cruciate ligament graft fixation technique combining direct and indirect fixation methods, including autologous bone augmentation of the drill tunnel using cancellous bone fragments.

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.

[Cartilage chip transplantation for cartilage defects of the first metatarsophalangeal joint]. / Minced Cartilage bei Knorpeldefekten am Großzehengrundgelenk.

OBJECTIVE: Treatment of circumscribed cartilage defects in the first metatarsophalangeal joint (MTP1) using autologous cartilage fragments. INDICATIONS: Full thickness cartilage defects (ICRS IV) or focal osteoarthritis in combination with hallux rigidus. CONTRAINDICATIONS: Pre-existing ankylosis of the metatarsophalangeal joint; global osteoarthritis of the joint; advanced osteoarthritis of the sesamoidal articulation; osteonecrotic cysts in the head of the first metatarsal bone. SURGICAL TECHNIQUE: Preparation of the metatarsophalangeal joint. Mobilization of the first metatarsal head. Harvesting of the cartilage fragments from the dorsal rim portion as part of the cheilectomy. Mincing the cartilage fragments with a 3.0 mm shaver in sterile conditions. Augmenting the cartilage fragments with autologous conditioned plasma (ACP). Preparing the defect area and creation of a "contained" defect. Replantation of the resulting minced cartilage mass into the defect of the articular surface on the first metatarsal head. POSTOPERATIVE MANAGEMENT: Immobilization of the MTP1 for 48 h. Intensive physiotherapy for 3 months. Full weight bearing after reduced swelling. RESULTS: In 2020, 5 patients were treated with the method described and followed up for a period of 1 year. All patients were subjectively satisfied with the result of the operation. There were no relevant surgery-associated complications.

Minced Cartilage Implantation for a Cystic Defect on the Femoral Head-Technical Note.

Chondral injuries of the femoral head and their possible progression to osteoarthritis is well known. Regarding focal lesions in young patients, microfracturing or autologous chondrocyte implantation (ACI) are the most frequent used techniques to address them. Although ACI provides the better tissue quality, it is a two-step procedure and needs a lot of resources. Mincing cartilage is an old technique that has become popular again over the last few years, with good short-term results in threatening cartilage lesion in the knee. It seems intriguing to transfer this technique to the hip because you can harvest good-quality cartilage from the cam lesion, and it is a one-step procedure using autologous thrombin and fibrin. This technical note describes the repair of a parafoveal chondral defect using minced cartilage via surgical dislocation of the hip.

[Patellofemoral cartilage repair]. / Therapie patellofemoraler Knorpelschäden.

Anterior knee pain is a frequent symptom in young athletes. Symptomatic patellofemoral cartilage defects can occur after trauma, especially after patellar dislocation. Numerous cartilage repair methods are currently available. Due to co-pathologies, the outcome after patellofemoral cartilage repair is inferior to the treatment of cartilage defects of the tibiofemoral joint. Adequate addressing of coexisting pathologies is essential for treatment success. This review provides an overview of the different techniques of patellofemoral cartilage repair.

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.

Towards planning of osteotomy around the knee with quantitative inclusion of the adduction moment: a biomechanical approach.

PURPOSE: Despite practised for decades, the planning of osteotomy around the knee, commonly using the Mikulicz-Line, is only empirically based, clinical outcome inconsistent and the target angle still controversial. A better target than the angle of frontal-plane static leg alignment might be the external frontal-plane lever arm (EFL) of the knee adduction moment. Hypothetically assessable from frontal-plane-radiograph skeleton dimensions, it might depend on the leg-alignment angle, the hip-centre-to-hip-centre distance, the femur- and tibia-length. METHODS: The target EFL to achieve a medial compartment force ratio of 50% during level-walking was identified by relating in-vivo-measurement data of knee-internal loads from nine subjects with instrumented prostheses to the same subjects' EFLs computed from frontal-plane skeleton dimensions. Adduction moments derived from these calculated EFLs were compared to the subjects' adduction moments measured during gait analysis. RESULTS: Highly significant relationships (0.88 ≤ R2 ≤ 0.90) were found for both the peak adduction moment measured during gait analysis and the medial compartment force ratio measured in vivo to EFL calculated from frontal-plane skeleton dimensions. Both correlations exceed the respective correlations with the leg alignment angle, EFL even predicts the adduction moment's first peak. The guideline EFL for planning osteotomy was identified to 0.349 times the epicondyle distance, hence deducing formulas for individualized target angles and Mikulicz-Line positions based on full-leg radiograph skeleton dimensions. Applied to realistic skeleton geometries, widespread results explain the inconsistency regarding correction recommendations, whereas results for average geometries exactly meet the most-consented "Fujisawa-Point". CONCLUSION: Osteotomy outcome might be improved by planning re-alignment based on the provided formulas exploiting full-leg-radiograph skeleton dimensions.

Arthroscopic Minced Cartilage Implantation for Chondral Lesions at the Talus: A Technical Note.

In the past few years, autologous chondrocyte implantation has been shown to be the most suitable cartilage reconstructive technique with the best tissue quality. Although this method is part of the standard surgical repertoire in the knee joint, it has so far not been an established method in the ankle because there are no prospective randomized controlled studies to prove a significant advantage over alternative methods of cartilage repair. The methods most frequently used in this context (e.g., marrow stimulation techniques) can, however, at most generate hyaline-like and thus biomechanically inferior regenerates. Minced cartilage implantation, on the other hand, is a relatively simple and cost-effective 1-step procedure with promising biological potential and-at least in the knee joint-satisfactory clinical results. We present an arthroscopic surgical technique by which the surgeon can apply autologous chondrocytes in a 1-step procedure (AutoCart; Arthrex, Munich, Germany) to treat articular cartilage defects in the ankle joint.

Arthroscopic Minced Cartilage Implantation (MCI): A Technical Note.

Articular cartilage lesions are identified with increasing frequency. Several cartilage repair techniques are available to treat symptomatic cartilage defects. The ultimate goal of any cartilage repair procedure is the prevention of premature osteoarthritis. Autologous chondrocyte implantation provides the best tissue quality. However, 2 operations and a resource-intense culturing process with high regulatory demands are disadvantages of this cartilage repair procedure. Furthermore, cellular dedifferentiation and senescence display further cell culture-associated drawbacks that hamper the procedure. Minced cartilage implantation is a relatively simple and cost-effective one-step procedure with promising biologic potential and satisfying clinical results. We present an arthroscopic surgical technique where the surgeon can apply autologous chondrocytes in a one-step procedure to treat articular cartilage defects at the knee joint.

Comparison of Human Articular Cartilage Tissue and Chondrocytes Isolated from Peripheral versus Central Regions of Traumatic Lesions.

OBJECTIVE: Cellular and molecular events occurring in cartilage regions close to injury are poorly investigated, but can possibly compromise the outcome of cell-based cartilage repair. In this study, key functional properties were assessed for cartilage biopsies collected from the central part of traumatic joint lesions (central) and from regions surrounding the defect (peripheral). These properties were then correlated with the quality of the initial cartilage biopsy and the inflammatory state of the joint. DESIGN: Cartilage samples were collected from knee joints of 42 patients with traumatic knee injuries and analyzed for cell phenotype (by reverse transcriptas-polymerase chain reaction), histological quality, cellularity, cell viability, proliferation capacity, and post-expansion chondrogenic capacity of chondrocytes (in pellet culture). Synovium was also harvested and analyzed for the expression of inflammatory cytokines. RESULTS: Cartilage quality and post-expansion chondrogenic capacity were higher in peripheral versus central samples. Differences between these 2 parameters were more pronounced in joints with high inflammatory features characterized by >100-fold difference in the mRNA levels of IL6 and IL8 in the corresponding synovium. Peripheral chondrocytes isolated from good- versus bad-quality biopsies expressed higher levels of collagen II/I and aggrecan/versican and lower levels of MMP13 and ADAMTS5. They also exhibited reduced proliferation and enhanced cartilage-forming capacity. CONCLUSIONS: Chondrocytes at the periphery of traumatic lesions better maintain properties of healthy cartilage compared to those isolated from the center, even when derived from bad-quality tissues harvested from highly inflamed joints. Future studies are necessary to investigate the change of functional properties of peripheral chondrocytes over time.

Synovial Fluid Biomarkers in Knee Osteoarthritis: A Systematic Review and Quantitative Evaluation Using BIPEDs Criteria.

OBJECTIVE: The aim of this systematic review was to analyze the evidence about the efficacy of the several synovial fluid (SF) biomarkers proposed for knee osteoarthritis (OA), categorizing them by both molecular characteristics and clinical use according to the BIPEDs criteria, to provide a comprehensive and structured overview of the current literature. DESIGN: A systematic review was performed in May 2020 on PubMed, Cochrane Library, and Embase databases about SF biomarkers in patients with knee OA. The search was limited to articles in the last 20 years on human studies, involving patients with knee OA, reporting SF biomarkers. The evidence for each selected SF biomarker was quantified according to the 6 categories of BIPEDs classification. RESULTS: A total of 159 articles were included in the qualitative data synthesis and 201 different SF biomarkers were identified. Among these, several were investigated multiple times in different articles, for a total of 373 analyses. The studies included 13,557 patients with knee OA. The most promising SF biomarkers were C4S, IL-6, IL-8, Leptin, MMP-1/3, TIMP-1, TNF-α, and VEGF. The "burden of disease" and "diagnostic" categories were the most represented with 132 and 106 different biomarkers, respectively. CONCLUSIONS: The systematic review identified numerous SF biomarkers. However, despite the high number of studies on the plethora of identified molecules, the evidence about the efficacy of each biomarker is supported by limited and often conflicting findings. Further research efforts are needed to improve the understanding of SF biomarkers for a better management of patients with knee OA.

Autologous Minced Cartilage Implantation for Treatment of Chondral and Osteochondral Lesions in the Knee Joint: An Overview.

Cartilage defects in the knee are being diagnosed with increased frequency and are treated with a variety of techniques. The aim of any cartilage repair procedure is to generate the highest tissue quality, which might correlate with improved clinical outcomes, return-to-sport, and long-term durability. Minced cartilage implantation (MCI) is a relatively simple and cost-effective technique to transplant autologous cartilage fragments in a single-step procedure. Minced cartilage has a strong biologic potential since autologous, activated non-dedifferentiated chondrocytes are utilized. It can be used both for small and large cartilage lesions, as well as for osteochondral lesions. As it is purely an autologous and homologous approach, it lacks a significant regulatory oversight process and can be clinically adopted without such limitations. The aim of this narrative review is to provide an overview of the current evidence supporting autologous minced cartilage implantation.

Is There a Scientific Rationale for the Refixation of Delaminated Chondral Flaps in Femoroacetabular Impingement? A Laboratory Study.

BACKGROUND: Debonding of the acetabular cartilage is a characteristic type of hip damage found in cam-type femoroacetabular impingement (FAI), which remains a treatment challenge. In addition to resection, refixation of these flaps using fibrin sealants has been recently suggested. However, there is only limited evidence available that the proposed refixation method results in sufficient viable cartilage formation to ensure long-term flap grafting and restored tissue function. QUESTIONS/PURPOSES: To determine the flap tissue characteristics that would justify refixation of delaminated chondral flaps with a fibrin sealant, we characterized (1) the extracellular matrix (ECM) of chondral flaps in terms of chondrocyte viability and distribution of ECM components and (2) the chondrogenic potential of resident cells to migrate into fibrin and produce a cartilaginous matrix. METHODS: Ten acetabular chondral flaps and three non-delaminated control cartilage samples were resected during surgery. Chondrocyte viability was quantified using a live-dead assay. To assess the ECM, histological staining of glycosaminoglycans, collagen II, and collagen I allowed the qualitative study of their distribution. The ability of chondrocytes to migrate out of the ECM was tested by encapsulating minced flap cartilage in fibrin gels and semi-quantitatively assessing the projected area of the gel covered with migrating cells. The potential of chondrocytes to produce a cartilaginous matrix was studied with a pellet assay, a standard three-dimensional culture system to test chondrogenesis. Positive controls were pellets of knee chondrocytes of age-matched donors, which we found in a previous study to have a good capacity to produce cartilage matrix. Statistical significance of controlled quantitative assays was determined by the Student's t-test with Welch's correction. RESULTS: The proportion of viable chondrocytes in flaps was lower than in nondelaminated cartilage (50% ± 19% versus 76 ± 6%; p = 0.02). Histology showed a disrupted ECM in flaps compared with nondelaminated controls, with the presence of fibrillation, a loss of glycosaminoglycan at the delaminated edge, collagen II throughout the whole thickness of the flap, and some collagen I-positive area in two samples. The resident chondrocytes migrated out of this disrupted ECM in all tested samples. However in pellet culture, cells isolated from the flaps showed a qualitatively lower chondrogenic potential compared with positive controls, with a clearly inhomogeneous cell and matrix distribution and an overall smaller projected area (0.4 versus 0.7 mm; p = 0.038). CONCLUSION: Despite the presence of viable chondrocytes with migration potential, the cells resided in a structurally altered ECM and had limited capacity to deposit ECM, leading us to question their capacity to produce sufficient ECM within the fibrin sealant for stable long-term attachment of such flaps. CLINICAL RELEVANCE: The characterization of delaminated cartilage in cam FAI patients suggests that the refixation strategy might be adversely influenced by the low level of ECM produced by the residing cells.

Patient Expectations about Communication in the Perioperative Setting of Elective Knee Surgery - a Questionnaire-based Cross-sectional Study.

BACKGROUND: Patient expectations are an issue which is attracting increased interest in outcome research for knee surgery procedures. So far, research into patient expectations has mainly focused on the procedure and postoperative functional improvements. The purpose of this study was to identify patient expectations in the perioperative setting. MATERIAL AND METHODS: This was a single-center prospective study. A 17-item questionnaire (ordinal answer scale) about patients' perioperative expectations was developed and completed by patients undergoing elective joint-preserving knee surgery. The study covered a period of 3 months and included all patients consecutively undergoing knee surgery. Subgroup analysis was performed for gender, age and type of insurance. RESULTS: 111 consecutive patients completed the questionnaire on admission. Significant preferences for one answer option were found for 13 out of 17 items. Patients considered it "unimportant" whether or not the physician wore a white coat during the consultation and "very important" that the first medical consultation after the patient was discharged from hospital was with the surgeon who had performed their operation. A concise explanation of the surgical procedure using images, talking to the surgeon the day before surgery and immediately after surgery, having their wound personally inspected by the surgeon, and, finally, the availability of the surgeon by phone were regarded as "important". There were no differences in patient responses between the different subgroups. CONCLUSION: Patients expect a high personal commitment and availability of the surgeon during the entire perioperative setting, starting from the first consultation and continuing during follow-up examinations.