Inclusion Criteria - Phase 1
- 21-65 years.
- Body Mass Index (BMI) ≤ 35.
- Singular treatable joint surface lesion, ICRS Grade 3 or 4, located on the medial or lateral femoral condyle.
- Symptomatic, single treatable area 1 - 3.8cm2.
- Knee Injury and Osteoarthritis Outcome Score (KOOS) pain subscale score between 20 and 65.
- Stable knee.
- Non-responsive to a minimum of 3 weeks of conservative treatment, consisting of non-steroidal anti-inflammatory drugs and/or physical therapy.
Inclusion Criteria - Phase 2
- 21-65 years.
- Body Mass Index (BMI) ≤ 35.
- Up to three treatable joint surface lesion(s), ICRS Grade 3 or 4, located on the medial or lateral femoral condyle(s).
- Symptomatic total treatable area 1 - 10cm2.
- Knee Injury and Osteoarthritis Outcome Score (KOOS) pain subscale score between 20 and 65.
- Stable knee.
- Non-responsive to a minimum of 3 weeks of conservative treatment, consisting of non-steroidal anti-inflammatory drugs and/or physical therapy.
Exclusion Criteria - Phase 1 & 2
HYALEX Implant, Surgical Technique, and Lesion Site Exclusions:
- Known allergy to polyurethanes, bone cement, acrylic, or titanium.
- Lack of 2mm of healthy cartilage (ICRS Grade 0 or 1) and 2mm of vital bone wall on all sides of the implant site.
- Osteochondral defect affecting subchondral bone more than 11mm in depth from adjacent non-defect articular surface.
- Bipolar cartilage lesions involving patellar or tibial lesions ICRS Grade 3 - 4 opposite the lesion intended for treatment.
- Insufficient bone stock or bone density determined intra-operatively preventing implant press fit.
Patient Orthopaedic Health Exclusions:
- Kellgren and Lawrence (KL) grade 3 or 4 on standing radiographs as defined:
- Hip-knee-ankle (HKA) angle of greater than +/- 5 degrees (varus or valgus malalignment > 5 degrees) on standing X-ray.
- Lack of normally functioning contralateral knee that restricts activity.
- Insufficiency fracture of the femoral condyle or tibial plateau.
- Recent Osteochondritis Dissecans within 1 year.
- Diagnosis of a concomitant knee injury which the investigator believes may interfere with study participation or confound effectiveness assessment.
- Any known systemic cartilage and/or bone disorder, such as but not limited to osteoporosis, chondrodysplasia or osteogenesis imperfecta.
- A symptomatic musculoskeletal condition in the lower limbs that could impede effectiveness measurements in the target knee.
- Any known tumor of the treatment knee.
- Prior radiation therapy to the knee joint.
- Clinically significant or symptomatic vascular or neurological disorder of the lower extremities affecting gait or function.
- Untreated ACL and/or PCL deficiency or complex ligamentous instability of the study knee according to IKDC Grade C (abnormal) or D (severely abnormal).
Previous Surgery and Intervention Exclusions:
Previous surgery in the past 6 months on the index knee except for:
- Diagnostic knee arthroscopy and/or debridement / chondroplasty, and
- Meniscectomy
Previous intra-articular injections, including HA and steroids, within the last 3 months prior to the date of surgery.