Knee cartilage injuries involve damage to the articular cartilage that lines the ends of the femur, tibia, and patella. Because cartilage has no blood supply and limited capacity to repair itself, even localized injuries can progress to chronic pain and early arthritis. Treatment depends on defect size, depth, location, and patient factors, with preservation and restoration techniques used whenever the defect allows.
What Are Knee Cartilage Injuries?
The articular cartilage of the knee is a thin, durable layer covering the ends of the femur and the top surface of the tibia, with a separate layer on the undersurface of the patella. It allows the joint surfaces to glide across each other almost frictionlessly. Cartilage receives its nutrition from joint fluid rather than from blood vessels, which explains its limited healing capacity.
Cartilage injuries take several forms:
- Focal chondral defects from acute trauma (the pivot or impact that takes a divot out of the cartilage)
- Osteochondral fractures, in which cartilage and underlying bone are both damaged
- Osteochondritis dissecans, a fragment of cartilage and underlying bone that loses blood supply and may separate
- Chondromalacia, softening and fraying of cartilage often behind the patella
- Diffuse cartilage wear as part of early osteoarthritis
Location matters clinically. Defects on the weight-bearing surfaces of the femur and tibia produce different symptoms and require different treatment than defects behind the patella.
Causes and Risk Factors
- Acute impact or shear injuries during sport or trauma
- ACL or other ligament injuries, which commonly produce associated cartilage damage
- Chronic instability (ACL deficiency, patellar instability) with repetitive cartilage loading
- Prior meniscus surgery, which alters load distribution
- Malalignment of the knee that concentrates load on one area
- Post-traumatic changes after fractures involving the joint surface
Symptoms
- Deep knee pain with activity
- Catching, clicking, or locking in some cases
- Swelling with increased activity
- Crepitus with joint motion
- Loss of motion in end ranges
- Symptoms that do not fit a clear meniscus or ligament pattern
Diagnosis
Dr. Chudik’s evaluation includes the mechanism (if any) and the pattern of pain. Physical examination assesses motion, crepitus, alignment, and rule-out of other knee pathology. X-rays evaluate for osteochondritis dissecans, loose bodies, and early arthritic changes; weight-bearing views are preferred. MRI is the imaging study of choice and characterizes cartilage defects, their size, depth, and any associated subchondral bone changes. Arthroscopy provides the most definitive assessment and is both diagnostic and therapeutic. The Westmont office has on-site high-field MRI and X-ray.
Treatment
Non-surgical treatment is appropriate for smaller lesions and early disease. Options include activity modification, anti-inflammatory medication, a targeted physical therapy program for quadriceps and core strengthening, unloading bracing when indicated, and corticosteroid or hyaluronic acid injections for pain control.
Surgical treatment is considered for symptomatic lesions that do not respond to non-surgical care or for larger defects at risk of progression. Dr. Chudik performs arthroscopic cartilage procedures including:
- Debridement of unstable cartilage flaps
- Microfracture for small full-thickness defects, which stimulates fibrocartilage formation from marrow elements
- Osteochondral autograft transfer (OATS) for small to medium defects, using plugs from less loaded areas of the joint
- Osteochondral allograft transplantation for larger defects, using donor cartilage with underlying bone
- Autologous chondrocyte implantation (ACI) or matrix-assisted techniques for selected cases
- Removal of loose bodies from osteochondritis dissecans when indicated
The choice of procedure depends on defect size, location, depth, and patient age and activity level.
Recovery and Outcomes
Recovery depends on the procedure. Debridement allows return to activity within weeks. Microfracture typically requires four to six weeks of protected weight-bearing followed by progressive loading, with return to sport at four to six months. Osteochondral transplantation and ACI have longer recoveries, typically with return to sport at six to nine months or longer.
Outcomes for focal cartilage procedures are best when the defect is identified and treated early, before it enlarges or produces secondary damage to the opposing surface. Concomitant alignment correction or ligament reconstruction, when indicated, improves outcomes by correcting the underlying mechanical load.
When to See Dr. Chudik
Schedule an evaluation if knee pain does not fit a clear meniscus or ligament pattern, if you have catching or locking with motion, or if prior imaging has identified a cartilage defect. Call 630-324-0402 or request an appointment online.