The OSSIOfiber® Trimmable Fixation Nails are indicated for maintenance of alignment and fixation of bone fractures, osteotomies, arthrodesis and bone grafts in the presence of appropriate additional immobilization (e.g., rigid fixation implants, cast, brace). Our hypothesis is that the use of OSSIOfiber® Trimmable Fixation Nails for treating subchondral insufficiency of the knee will result in improvement of patient-reported outcomes and imaging findings. The primary objective of this study is to evaluate the effectiveness of implanting bio-integrative OSSIOfiber® Trimmable Fixation Nails, organized in a bi-cortical rafter formation within the tibia or femur for the management of subchondral insufficiency. The OSSIOfiber® Trimmable Fixation Nails used in this study will be considered on-label.

Inclusion Criteria:

• Agree to study participation and consent obtained.
• Able to attend all postoperative clinical visits, undergo imaging procedures, and complete relevant questionnaires.
• Subjects between the ages of 18 to 75 years.
• Body Mass Index < 40.
• Has knee pain in the study knee lasting at least 3 months and has had at least moderate pain recorded on a standard of care (SOC) preoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) and/or Numeric Pain Reported Scale (0-10) questionnaire. The study team may utilize these verbal pain scores collected during the clinic intake process for screening purposes. If the patient was not administered the verbal pain score, the patient will be consented, administered the pain survey, and withdrawn if moderate pain score was not recorded.
• At least 3-months without steroid injection or any other non-surgical intervention administered to study knee.
• Candidate for knee arthroscopy due to meniscal tear, loose body, unstable articular cartilage or mechanical symptoms.
• Uni-compartmental Kellgren-Lawrence grade 2-3 osteoarthritis in the study tibia or femur.
• Bone Marrow Lesion (BML) confirmed on magnetic resonance imaging in the femur, tibia or both.
• Cartilage lesion on the tibial or femoral condyle(s) of a grading ≤4 by either the International Cartilage Repair Society or Outerbridge classifications verified at the time of arthroscopy.

Exclusion Criteria:

• Imaging evidence of the study knee that includes any of the following:

  1. Kellgren-Lawrence grade 4 osteoarthritis.
  2. Collapse of subchondral bone.
  3. Avascular Necrosis (AVN).
  4. Osteochondral defect overlying the BML
  5. BML located at ACL or PCL insertions

• Clinical evidence of the study knee that includes any of the following:

  1. History of rheumatoid arthritis, septic arthritis, reactive arthritis, gout or pseudogout, secondary arthropathy (e.g., hemochromatosis, hemophilia, or psoriasis).
  2. Osteochondritis dissecans.
  3. Frank ligamentous instability.
  4. Neuromuscular deficiency or other that would limit the ability to do a functional assessment.

• Bi-cortical nail implantation cannot be achieved, including where the required nail length is not yet available.

• Current tobacco use or has quit within 3 months of study enrolment.

• Substance abuse history.

• Diabetes mellitus, HbA1c>8

• High surgical risk due to pre-existing conditions.

• Currently pregnant or has plans to become pregnant prior to surgery.

• Active infection or history of chronic infection in study knee.

• Will require concomitant procedures within study knee, including but not limited to ligament reconstruction, tendon repair, meniscus repair, microfracture, osteotomy, or osteochondral transplantation (Meniscal tears, including chronic, are acceptable if no repair is required)

• Significant malalignment (varus or valgus) of the knee (>8°)

• Use of augmentation or concomitant biologic therapy during surgery.

• Contraindications to magnetic resonance imaging.

• Any condition which in the view of the treating physician makes it inadvisable for the subject to participate in the study.