Chondromalacia: Causes, Symptoms and Treatment

What is Chondromalacia?

Chondromalacia (from Greek chondros = cartilage, malakia = softness) is a pathological softening and structural deterioration of cartilage tissue. The most commonly affected form is chondromalacia patellae, which involves damage to the cartilage on the underside of the kneecap (patella). However, the condition can develop in any joint lined with cartilage.

The disease progresses through several stages and, if left untreated, can eventually lead to osteoarthritis. It is particularly common in younger, physically active individuals and in people with certain lower limb malalignment conditions.

Causes

The causes of chondromalacia are diverse and often multifactorial:

• Overuse: Repetitive mechanical stress from intense physical activities such as running, cycling, or squatting can damage cartilage over time.
• Malalignment: Improper tracking of the kneecap within the groove of the femur (e.g., knock-knees) increases pressure on specific cartilage areas.
• Muscle imbalances: Weakness or tightness in the thigh muscles can cause the patella to track incorrectly.
• Trauma: Direct injury to the joint or kneecap from falls or blows.
• Age-related wear: Natural decline in cartilage quality and resilience with advancing age.
• Genetic predisposition: A family history of cartilage weakness may increase the risk.

Grades of Severity

Chondromalacia is classified into four grades according to the internationally recognized Outerbridge Classification:

• Grade I: Softening and swelling of the cartilage with an intact surface.
• Grade II: Superficial fibrillation and fissuring of the cartilage surface (diameter less than 1.5 cm).
• Grade III: Deep fissuring and fragmentation of the cartilage (diameter greater than 1.5 cm).
• Grade IV: Full-thickness cartilage loss exposing the underlying bone (subchondral bone).

Symptoms

Symptoms of chondromalacia can vary depending on the severity and location of the cartilage damage:

• Dull, aching pain behind or around the kneecap
• Worsening pain when climbing stairs, squatting, walking downhill, or sitting for prolonged periods
• Grinding, clicking, or grating sensations in the knee (crepitus)
• Swelling and warmth around the knee joint
• A feeling of knee instability or giving way
• Pain following physical activity or prolonged exertion

Diagnosis

Diagnosis of chondromalacia is made through a combination of clinical examination and imaging:

• Medical history and physical examination: Assessment of pain characteristics, triggers, and duration; specific clinical tests such as the patellar compression test or the Clarke test.
• X-ray: Used to assess bone structure and joint space; cartilage damage itself is not directly visible on plain X-rays.
• MRI (Magnetic Resonance Imaging): The gold standard for visualizing cartilage changes; allows accurate assessment of the extent and severity of damage.
• Arthroscopy: Direct inspection of the cartilage through minimally invasive joint surgery; therapeutic intervention can be performed simultaneously.

Treatment

Conservative Treatment

In most cases, chondromalacia is first managed with non-surgical approaches:

• Rest and activity modification: Avoiding activities that trigger or worsen pain.
• Physiotherapy: Targeted strengthening of the thigh muscles (especially the vastus medialis obliquus) to stabilize the kneecap.
• Orthotic support: Patellar braces or custom insoles help to center the kneecap and reduce pressure on the damaged cartilage.
• Medication: Pain relievers and anti-inflammatory drugs (NSAIDs) to reduce acute discomfort and swelling.
• Physical therapy modalities: Ice application, ultrasound therapy, or electrotherapy to support tissue healing.

Surgical Treatment

For advanced cases or when conservative treatment is insufficient, surgical options may be considered:

• Arthroscopic chondroplasty: Removal of damaged cartilage fragments and smoothing of the cartilage surface.
• Microfracture surgery: Small holes are drilled into the bone to stimulate the formation of fibrocartilage repair tissue.
• Autologous chondrocyte implantation (ACI): Cartilage cells are harvested from the patient, expanded in a laboratory, and then implanted into the defect.
• Realignment procedures: In cases of structural malalignment, corrective surgery can normalize the biomechanical load on the cartilage.

Prevention

The following measures may help prevent the development or progression of chondromalacia:

• Regular but moderate exercise with adequate recovery periods
• Strengthening programs targeting the muscles that stabilize the knee joint
• Appropriate footwear and orthopedic insoles where indicated
• Weight management to reduce joint loading
• Warm-up and stretching routines before physical activity

References

1. Outerbridge RE. - The etiology of chondromalacia patellae. Journal of Bone and Joint Surgery, 1961.
2. Buckwalter JA, Mankin HJ, Grodzinsky AJ. - Articular cartilage and osteoarthritis. Instructional Course Lectures, 2005.
3. Brittberg M, Lindahl A, Nilsson A, et al. - Treatment of deep cartilage defects in the knee with autologous chondrocyte transplantation. New England Journal of Medicine, 1994.