Chondromalacia Patella Classification and Management

Classification and Diagnosis

The Outerbridge Classification system is used to classify chondromalacia patella, with grades ranging from 0 (normal cartilage) to 4 (loss of cartilage and exposed subchondral bone), where Grade 2 involves fragmentation and fissuring involving area <1.5 cm in diameter, Grade 3 involves area >1.5 cm in diameter, and Grade 4 involves loss of cartilage and exposed subchondral bone, as defined by the American Academy of Orthopaedic Surgeons 1

The American College of Rheumatology/Arthritis Foundation does not recommend stem cell injections for cartilage regeneration in osteoarthritis due to concerns regarding heterogeneity and lack of standardization, with a strength of evidence considered low due to the limited number of studies 2
Long-term monitoring is important as chondromalacia may progress to osteoarthritis if not properly managed, with a moderate strength of evidence supporting the need for ongoing monitoring, as recommended by the American Academy of Orthopaedic Surgeons 1

The Outerbridge Classification is used to grade severity and guide treatment decisions, with Grade 1 characterized by cartilage softening and swelling, according to the American Academy of Orthopaedic Surgeons 3

Microfracture is recommended for contained, full-thickness defects in patients with minimal osteoarthritis (Tönnis grade ≤1), as stated by the American Academy of Orthopaedic Surgeons 3, 4
For lesions 2-6 cm², microfracture remains first-line for acetabular lesions, and mosaicplasty or single-plug osteochondral allograft is considered for femoral head lesions, according to the American Academy of Orthopaedic Surgeons 4
For lesions >6 cm², conversion to total hip arthroplasty should be considered in appropriate candidates, as recommended by the American Academy of Orthopaedic Surgeons 4

The American College of Rheumatology recommends paracetamol (acetaminophen) as the preferred first-line oral analgesic for pain control in patients with chondromalacia patellae, though efficacy is uncertain and likely small 5
The American College of Rheumatology suggests that NSAIDs can be used when paracetamol is insufficient, but long-term use carries gastrointestinal and cardiovascular risks 5

The American College of Rheumatology conditionally recommends patellofemoral braces for patients with patellofemoral knee osteoarthritis causing significant impact on ambulation, joint stability, or pain 6
The American College of Rheumatology conditionally recommends kinesiotaping for knee joint involvement 6
Optimal management with bracing requires clinician familiarity with various brace types and expertise in fitting, as recommended by the American College of Rheumatology 6

Conservative treatment should be attempted first, though it serves primarily as a temporizing measure and does not address the underlying cartilage defect, as recommended by the American Academy of Orthopaedic Surgeons 7

For patients with focal, contained lesions <4 cm² with minimal osteoarthritis, microfracture is indicated, with a technique involving debridement of friable cartilage, creation of a perpendicular edge of healthy cartilage, and creation of 3-4mm deep holes spaced 3-4mm apart in subchondral bone to bring marrow cells and growth factors into the defect, resulting in a mean 93% ± 17% fill at second-look arthroscopy with good-quality cartilage macroscopically 7, 8, 9