Funding restrictions

Femoroacetabular impingement (FAI) is a hip disorder resulting from a mismatch of the hip joint, resulting in hip pain and can potentially cause osteoarthritis. As the head of the femur (ball of the hip) and the acetabulum (socket of the hip) impinge or rub together with this mismatch, patients can suffer damage to their articular cartilage which covers both. Currently, the standard of care to surgically treat articular cartilage damage is a procedure called 'microfracture' - where the surgeon makes multiple holes in the bone under the defects causing bone marrow cells and blood from the holes to combine to form a "super clot" that covers the damaged area and is meant to be the basis for new tissue formation or 'fibrocartilage'. However, native articular cartilage is made of hyaline, rather than fibrocartilage, which is a more flexible and durable tissue able to withstand a great deal of force on the hip when it moves. Therefore, a more recently developed strategy that has gained popularity for use in the repair of articular cartilage in the knee involves the implantation of bone marrow aspirate (BMA) along with a scaffold made of hyaluronic acid (HA) in a single-step procedure, with the goal of promoting new hyaline-like tissue. While this has shown promising results in treating knee cartilage damage, this treatment method has yet to be studied in the hip. This randomized controlled trial will evaluate in patients with painful articular cartilage damage of the hip, the effect of implantation of an HA scaffold along with BMA in comparison to microfracture on hip pain and function, cartilage regeneration, and any complications at 24 months post-surgery.

Inclusion Criteria:

1. Male and female patients aged 18-40 years
2. Hip pain lasting 6 months or more with no relief from documented non-operative modalities
3. Cam, Pincer, or Mixed FAI
4. Focal articular cartilage defects of the acetabulum on MRI, confirmed to be full thickness (International Cartilage Regeneration and Joint Preservation Society (ICRS) grade 3 or 4) during arthroscopic examination
5. Focal acetabular articular cartilage lesions measuring between 1x1 cm2 and 5x5 cm2 on MRI and confirmed on arthroscopic examination
6. Patient agrees to participate in the study-specific postoperative rehabilitation protocol
7. Patient can speak, read, and understand the language of the site
8. Patient has provided informed consent

Exclusion Criteria:

1. Cartilage defects of the femoral head
2. Previous surgery on the study hip
3. Traumatic chondral injury of the hip from a single event
4. Presence of advanced osteoarthritis (Tonnis grade 2 or 3)
5. Known hypersensitivity or allergy to hyaluronate
6. Evidence of hip dysplasia (i.e. lateral centre edge angle < 20˚)
7. Evidence of acetabular over coverage such as coxa profunda or coxa protrusion
8. Immunosuppressive or anti-proliferative medication use
9. Chronic pain syndromes
10. Significant medical co-morbidities (requiring assistance for activities of daily living (ADLs))
11. History of paediatric hip disease
12. Uncontrolled diabetes
13. Contraindications to MRI imaging (e.g. claustrophobia)
14. Patient is involved in ongoing legal or workplace claims
15. Patient is incarcerated
16. Patient who will likely have problems, in the judgement of the investigator, with maintaining follow-up

The outcome assessors and those performing data entry and analysis will be blinded to the treatment allocation. Although patients will not be told which treatment they received, blinding may not be feasible given the intervention group will have an additional bone marrow harvest site incision at the iliac crest.