A Comparison of JointRep® and Microfracture in Repair of Cartilage Lesions on the Femoral Condyle or Trochlea,

Inclusion Criteria: * Be between 18-65 years old * Have one or two focal articular cartilage lesion(s) (ICRS Grade 3 or 4A) on the femoral condyles or trochlea of the index knee; patellar tracking must be normal if the index lesion(s) is on the trochlea. Individually, a lesion can be between 1-7cm2. If more than one lesion is present, the sum of the two lesions should not exceed 10cm2. * Within 6 months prior to treatment, have a Magnetic Resonance Imaging (MRI) or arthroscopic confirmation of lesion(s) in the index knee. * For patients older than 40 y.o, to have a radiological Kellgren and Lawrence (K\&L) grading from a standing knee radiograph taken less than 6 months previously, Grade 1 or * If not, an actual test will be performed as part of the visit 1 procedures. * Have a clinically stable knee, with no ligament deficiencies (\<5mm side-to-side difference on Lachman and varus/valgus stress testing \& Grade 0 or 1 on Pivot shift test) and the meniscal rims are intact (a maximum of 50% resection is allowed) * Be able to give voluntary, written informed consent to participate and have signed an Informed Consent Form specific to this study * VAS pain great than or equal to 4 in the last week. * Be willing and able to comply with all study procedures including all preoperative, post-operative and rehabilitation requirements * If female and of child-bearing potential, must report double-barrier, contraceptive use (e.g. use of birth-control pill and condom) for at least 2 months prior to treatment and in the 12 months following treatment. * If female and of child-bearing potential, have a negative pregnancy test prior to the surgical procedure and no intention of becoming pregnant in the 12 months following treatment. Exclusion Criteria: * Have a Body Mass Index (BMI) \>35kg/m2 * Have more than two lesions (ICRS grade 3 or 4A) on any surface in the index knee * Have "kissing" or opposing lesion(s) (ICRS grade 3 or 4A) of the condyle, tibia or patella in the index knee; additional linear lesions which bear Grade 3 or 4 characteristics may be acceptable if they are determined by the Investigator to be incidental, not clinically relevant, and consistent with the subject demographic * Have malalignment of \>5 degrees varus or valgus in the index knee based on standard AP x-rays requiring an osteotomy * Have had any surgical treatment for cartilage repair in the index knee within 1 year prior to treatment * Have had intra-articular injections within 3 months in the index knee * Have a diagnosis of a concomitant knee injury which may confound assessment of the index knee (e.g., important meniscal injury) * Have significant pain emanating from other lower body joints in the ipsilateral (hip, ankle) or contralateral (hip, knee, ankle) limb. * Have known allergies to shellfish * Have a known history of crystalloid or inflammatory arthropathy * Have any condition that is unrelated to the index knee and significantly impairs walking ability (e.g., spinal stenosis, sciatica) * Have advanced musculoskeletal disease * Have active coagulation disorders * Are currently using antibiotics * Are participating concurrently in another clinical investigation, or have participated in a clinical investigation within the last 90 days, or intend to participate in another clinical investigation during the course of the study * Are currently abusing drugs or alcohol or have a history of the same within the last 12 months * Have any mental or psychological disorder that would impair their ability to complete the study questionnaires * Are currently breastfeeding or planning to breastfeed any time during the course of the study * Are currently a prisoner * Have significant comorbidities or conditions associated with high-risk for surgical or anesthetic survival (e.g., renal failure, peripheral vascular disease, unstable cardiac disease, poorly controlled diabetes, immunosuppression, etc.) * Have any medical condition or other circumstances, in the judgment of the investigator, that might interfere with the ability to return for follow-up visits, including any systemic illness, neuromuscular, neurosensory, or musculoskeletal deficiency that would render the subject unable to perform appropriate post-operative rehabilitation * Have any condition which, in the judgment of the Investigator, would preclude adequate evaluation of the device's safety and performance Intra-operative Exclusion Criteria: Subjects who meet any of the following intra-operative screening criteria will be excluded from participation in this study: * Have lesion(s) in the index knee that are not contained (intact shoulders) and/or exceed 7 cm² in total size after debridement for a single lesion and 10cm2 for more than one lesion, if within the same condyle or the trochlea. If only a single lesion suitable to be included is identified, it might be between 1-7cm2. * Minor concomitant procedures are allowed such as, but not limited to: 1. Removal of loose bodies 2. Plica excision 3. Minor synovial removing 4. Minor chondroplasty (debridement) 5. Lysis of adhesions 6. Meniscal trimming/suturing which respects the exclusion criteria.