Biomaterials and Mesenchymal Stem/Stromal Cells in the Treatment of Knee Articular Surface Lesions

Originally published in 1998, the Knee injury and Osteoarthritis Outcome Score (KOOS) assesses patient pain (9 items), other symptoms (7 items), function in daily living (17 items), function in sport and recreation (5 items), and knee related quality of life (4 items). Scores range from 0 to 100 with a score 0 being the worst score and 100 indicating no impairment.

KOOS subscales postoperative improvements will be calculated as differences between preoperative and postoperative scores at the final follow up. As secondary outcome measures will be calculated all KOOS subscales improvements, beside KOOS subscale Pain, which is determined as the primary outcome measure.

Paired Student t test will be applied to compare preoperative and postoperative values of all KOOS subscales.

Serious adverse events (SAE) are defined as any hospitalization or revision surgery (arthrofibrosis, synovitis, infection, hardware problem, pulmonary embolism, etc.), while graft failures (GF) as revision surgery to the lesion or confirmed indication for it. SAE will be further classified as related (arthrofibrosis, synovitis, graft hypertrophy/delamination, etc.) or unrelated (hardware removal, meniscus or ligament injuries, new cartilage lesions, pulmonary embolism, etc.) to the graft.

Samples for cell counting (100 µl), fibroblast colony forming units (CFU-F) assay (1-2 ml) and flow cytometry (1-2 ml) will be taken before and after BMA processing with filter-based separation device. The total nucleated cell (TNC) count will be determined by counting white blood cells with hematology analyzer COULTER® Ac·T diff2™ (Beckman Coulter, Fullerton, CA, USA). MSCs content will be estimated with flow cytometry (FACSCalibur, BD Biosciences, San Jose, CA, USA) by determining CD271+ and CD45-cells, and concomitant assessment of their viability using 7-amino-actinomycin D (7-AAD) dye. Also, the CFU-F assay, which is a functional assay for measuring the frequency of MSCs with the colony forming abilities, will be performed. Briefly, cells will be seeded at least in duplicates into well culture plates and cultured in standard conditions: 37 °C, 5% CO2. After 14 days, colonies containing ≥ 50 fibroblastic cells will be manually counted under the stereomicroscope.

Tegner Activity Scale (TAS) is a one-item score that graded activity based on work and sports activities on a 11-level scale from 0 to 10. Zero represents disability because of the knee problems and 10 represents national or international level soccer.

TAS postoperative improvement will be calculated as difference between preoperative and postoperative scores at the final follow up.

Paired Student t test will be applied to compare preoperative and postoperative values of TAS.

EQ-5D-3L descriptive system consists of 5 dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression . Each dimension has 3 levels: no problems, some problems, and extreme problems. The respondent is asked to indicate his or her health state by ticking the box that marks the most appropriate level of problems in each dimension. A unique health state can be described according to the responses to the 5 questions. Health states defined in this way may be converted into a single summary index by applying a formula that attaches values to each of the levels in each dimension. States can be converted to a single value where 1 is equivalent to full health and 0 to a state equivalent to death.

EQ-5D-3L postoperative improvement will be calculated as difference between preoperative and postoperative scores at the final follow up.

Paired Student t test will be applied to compare preoperative and postoperative values of EQ-5D-3L .

EQ-VAS records the patient's self-rated health on a vertical visual analogue scale from 0 to 100, where 0 represents the worst health state imaginable and 100 represents the best health state imaginable.

EQ-VAS postoperative improvement will be calculated as difference between preoperative and postoperative scores at the final follow up.

Paired Student t test will be applied to compare preoperative and postoperative values of EQ-VAS5.

Regression models will be used to assess the influence of proposed predictors (patients' demographics, medical history, joint and lesions' characteristics, surgical and cellular parameters) on the postoperative improvements in clinical outcome measures (KOOS subscales, EQ-5D-3L, EQ-VAS, TAS). Statistical analysis will be performed with SPSS (version 25.0; IBM, Chicago, IL, USA).