HyaloFAST Trial for Repair of Articular Cartilage in the Knee

* Prospective, randomized, active treatment-controlled, evaluator-blinded (radiologist reviewer and physician evaluator) multicenter study (up to 40 sites in the US and EU). * All subjects that meet preoperative screening eligibility criteria will be randomized to treatment with Hyalofast® with BMAC or Microfracture. * Hyalofast® is a sterile, biodegradable non-woven pad (2 x 2 cm or 5 x 5 cm) that is composed of HYAFF-11®, a benzyl ester of hyaluronic acid. Hyalofast® acts as a biodegradable support for the autologous bone marrow aspirate concentrate. Hyalofast® is soft and conformable and can easily be cut to fit the lesion size. * Autologous bone marrow is harvested from the subject intraoperatively during the Index Procedure. Approximately 60 mL of bone marrow will be aspirated from the subject's iliac crest using the SmartPrep 2 Bone Marrow Processing Pack. The cellular rich portion will be concentrated via the SmartPrep BMAC 2 Centrifuge System at point-of-care to provide 7 mL of bone marrow aspirate concentrate (BMAC). 1 - 2 mLs will be used for post-procedure testing of total nucleated cells, cell viability, and sterility. * Hyalofast® with BMAC is implanted during either a standard knee arthroscopy or min-arthrotomy depending upon surgeon preferences and intra-operative findings. The lesion to be treated will be debrided to a stable cartilage margin. The defect will be sized and Hyalofast® will be cut to fit the lesion area. If necessary, more than one Hyalofast® pad can be overlapped to cover the lesion. 2 mL of BMAC will be loaded per Hyalofast® scaffold and then implanted to cover the defect. Hyalofast® with BMAC readily adheres to the site of application, but, if necessary, can be secured to the defect margins with an FDA-approved fibrin glue. * All subjects will be assessed at intervals post-procedure (1 month, 3 months, 6 months, 12 months, 24 months, and 36 months). * Subjects will be required to follow a strict pre-specified post-surgery rehabilitation protocol specific to the defect location. * Measures to assess effectiveness will be conducted at follow-ups, with the primary effectiveness endpoint assessment done at the 24 month timepoint. * Evaluators doing efficacy assessments of the subject and administering subject-reported outcome instruments will be blinded to the treatment. * Safety will be assessed by the collection of adverse events at all timepoints. * Magnetic Resonance Imaging (MRI) will be conducted at Screening, 1 month, 12 months, 24 months, and 36 months. Evaluation of the MRIs, including the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score, will be done by blinded radiologist reviewers. The one month MRI will be used as the baseline MRI for evaluation of treatment effectiveness.