What is a cartilage defect?
A focal cartilage defect is localized damage to the smooth articular cartilage of the knee — distinct from the widespread wear of arthritis. It commonly results from a single traumatic injury, repetitive stress, or osteochondritis dissecans (OCD), and disproportionately affects younger, active patients. Because cartilage has almost no blood supply, it has little capacity to heal itself once damaged — untreated defects can enlarge and progress toward early arthritis.
Typical symptoms are deep, localized knee pain with activity, swelling after activity, and catching or locking if a fragment is loose.
How is it diagnosed?
MRI is the key tool for sizing and characterizing a cartilage defect and checking the underlying bone. Defect size, location, and depth — along with your age, alignment, and activity goals — determine which restoration procedure is most appropriate.
Treatment options
Smaller defects may respond to activity modification and unloading strategies. When surgery is indicated, Dr. Pettit selects from the full menu of cartilage restoration procedures:
- Microfracture — a minimally invasive, single-stage arthroscopic option for small defects: tiny holes in the underlying bone release marrow cells that form repair tissue.
- OATS (osteochondral autograft) — transfers a plug of your own healthy cartilage and bone from a low-load area of the knee into the defect, providing immediately durable, native cartilage in a single stage.
- Osteochondral allograft — matched donor cartilage and bone for larger defects that an autograft can't cover, with no donor-site morbidity.
- MACI — a two-stage biologic option: your own cartilage cells are harvested arthroscopically, grown on a collagen scaffold in a lab, then implanted to fill moderate-to-large defects with durable, hyaline-like tissue.
When malalignment is overloading the damaged compartment, cartilage restoration is often combined with a realignment osteotomy — see the knee osteotomy guide.
Recovery & return to activity
Cartilage procedures share a staged recovery that protects the healing surface: protected weight-bearing for roughly the first 6 weeks (often with a brace, and a CPM machine for some procedures), progressive strengthening over months 2–4, and a gradual return to impact activity from months 4–9. Restored cartilage keeps maturing for up to a year — with MACI and allograft procedures, return to higher-impact and pivoting sport is typically 9–12 months, guided by graft maturation rather than the calendar.
Frequently asked questions
Why can't cartilage just heal on its own?
Cartilage has very limited blood supply, so it lacks the natural healing capacity that bone and other tissues have — which is why focal defects tend to persist or enlarge without treatment.
Which cartilage procedure is right for me?
It depends on the size, depth, and location of your defect, along with your age and activity goals. Small contained defects may do well with microfracture or OATS; larger defects are usually better served by MACI or an osteochondral allograft. Dr. Pettit walks through the options at your visit.
Why does MACI require two surgeries?
The first (arthroscopic) surgery harvests a small cartilage sample so your own cells can be grown on a scaffold in the lab; the second implants the mature graft into the defect.
How long until I can play sports again?
Most cartilage restoration patients return to impact activity gradually between months 4 and 9, with full return to higher-impact and pivoting sport at 9-12 months for MACI and allograft procedures, guided by healing on exam and imaging.
See Dr. Pettit
5 locations across Cincinnati & Northern Kentucky · (513) 354-3700