The study will be a prospective, multicenter clinical study evaluating clinical and patient reported outcome measures of subjects receiving IOBP® surgical technique using Angel cPRP and BMA processing system to treat subchondral bone pathology (SBP).

The study will be a prospective, multicenter, clinical study, enrolling both male and female patients. Subjects will be identified among the investigators' patient population scheduled for the IOBP® procedure and as being diagnosed with symptomatic SBP that have failed conservative management. IRB approval will be obtained by each participating institution.

The primary outcome measure is adverse event evaluation to determine whether IOBP® can prevent further surgical intervention (i.e., knee replacement surgery, HTO, or calcium phosphate stabilization of SBP) when used to treat symptomatic SBP of the knee.

Inclusion Criteria:

1. Able to read, understand, sign and complete informed consent
2. Male or female subject between the ages of 18-60 years
3. Subject has had pain for greater than three months
4. Subjects with single SBP in tibia or femur confirmed by minimum 1.5T MRI (including coronal, axial, sagittal, lateral femur, and lateral tibia views) and are candidates for an IOBP® procedure
5. Subject has stable ligaments
6. Subject has neutral alignment (max 5° varus or valgus)
7. Subject has a VAS score greater than or equal to five
8. Subject is scheduled to undergo surgical intervention using IOBP®

Exclusion Criteria:

1. Subject has diabetes Type I, Type II uncontrolled, or Type II insulin dependent
2. Subject has had lower extremity surgery within six months
3. Subject has had more than two prior surgical procedures in the operative leg
4. Subject has a neuromuscular condition
5. Subject has a current infection
6. Subject has a BMI >35
7. Subject has subchondral bone collapse or Kellgren Lawrence grade IV osteoarthritis
8. Subject has joint surface collapse in late stage avascular necrosis
9. Subject has majority of pain associated with alternate conditions
10. Subject has had subchondral bone pathology caused by acute trauma
11. Subject is not neurologically intact.
12. Subject has history of invasive malignancy (except non-melanoma skin cancer)
13. Subject that has a planned or scheduled additional surgery within the course of the study (lower extremity)
14. Subject has an active substance abuse problem
15. Subject is currently taking narcotic pain medication
16. Subject is pregnant or planning to become pregnant
17. Subject is on worker's compensation
18. Subject has a concomitant procedure not including meniscectomy, synovectomy, chondroplasty, or removal of loose body
19. Inability to complete study requirements and follow-up visits
20. Subject that has a bone marrow aspiration that does not meet 60cc

Subjects will be identified among the investigators' patient population scheduled for the IOBP® procedure and as being diagnosed with symptomatic SBP that have failed conservative management.