Evaluating the Effectiveness of Subchondroplasty for Treating Bone Marrow Lesions of the Knee

The primary objective of this randomized pilot study is to evaluate whether subchondroplasty combined with knee arthroscopy is more effective at reducing knee pain and improving knee function compared to knee arthroscopy alone. All knee function outcomes will be assessed at initial presentation, 3 months, 6 months, 12 months, and 24 months following surgery using validated questionnaires. Patient-reported pain will also be recorded at 2 weeks after surgery.

The secondary objective of the study is to determine whether the subchondroplasty and knee arthroscopy group has better bone quality and bone micro-architecture compared to the group receiving knee arthroscopy alone. Bone quality/micro-architecture will be evaluated at baseline, 3 months, and 12 months following surgery using Magnetic resonance imaging (MRI) and High-Resolution Peripheral Quantitative CT (HR-pQCT) imaging and at baseline, 3 months, 12 months, and 24 months after surgery using X-rays.

The investigators hypothesize that patients receiving subchondroplasty combined with arthroscopy will have reduced knee pain, improved knee function, and improved bone quality and micro-architecture compared to patients receiving arthroscopy alone who have symptomatic early osteoarthritis with the presence of at least one BML observed on MRI.

Patients who provide informed consent to enroll in the study will be scheduled for knee surgery and randomized to receive subchondroplasty and arthroscopy or arthroscopy alone. Knee function outcomes will be assessed at initial presentation, 3 months, 6 months, 12 months, and 24 months following surgical intervention. Patient-reported pain will also be recorded at 2 weeks following surgical intervention. The evaluation of bone quality and micro-architecture will occur at baseline, 3 months, and 12 months following surgical intervention. X-rays will also be evaluated at the 24-month time-point.

Eligibility Criteria:
Inclusion Criteria:

1. 40 years of age or older
2. Kellgren-Lawrence grade 1-3 osteoarthritis in the affected knee
3. Has experienced pain in the affected knee for at least 3 months
4. Candidate for knee arthroscopy (moderate to severe symptoms, lack of response to non-operative care, and/or mechanical symptoms)
5. Stable ligament exam
6. No additional injuries affecting the study knee or contralateral knee
7. Candidate for MRI (no pacemaker, aneurysmal clip, eye prosthesis, pregnancy, neurostimulator, implanted stimulator \[e.g. diabetes pump\])
8. Confirmed visualization of at least 1 bone marrow lesions using T2 weighted MRI

Exclusion Criteria:

1. Determined to not be a surgical candidate
2. Kellgren-Lawrence grade 4 osteoarthritis
3. Unable to fit in XtremeCT scanner (based on measurement at time of recruitment)
4. Contraindications to MRI
5. Any hardware present in either knee that could interfere with MRI signal
6. Bone marrow lesion(s) caused by acute trauma prior to enrolment
7. Radiographic mal-alignment defined by obvious valgus \> 7° or obvious varus \> 7° on measured hip-knee-ankle angle
8. No bone marrow lesion detected on baseline (pre-operative) MRI
9. Rheumatoid arthritis
10. Septic arthritis
11. Reactive arthritis
12. Gout
13. Osteochondritis dissecans of knee resulting in significant bone loss
14. Collapse of subchondral bone
15. Restricted knee range of motion: passive flexion \< 110° or a flexion contracture \> 30°
16. Ligament instability in either knee
17. History of other arthropathies (e.g. sickle cell or autoimmune disease)
18. History of uncontrolled diabetes: HbA1C level of 8 or higher, measured within 3 months of enrollment
19. Unable to perform a functional assessment of either knee
20. Current smoker or stopped smoking for less than 3 months
21. History of invasive malignancy (Unless treated in the past and has had no clinical signs or symptoms of malignancy for 5 years or longer)
22. Has a primary bone tumor in the knee or adjacent to the knee
23. Having surgery on another part of the lower limb in addition to the study procedure
24. Taking prescription pain medication other than NSAIDs or acetominophen
25. Active infection or a history of joint infection
26. Pursuing action through the Workers' Compensation Board - Alberta
27. BMI \> 40