Chondromalacia patella (knee pain) is the softening and breakdown of the tissue (cartilage) on the underside of the kneecap (patella). Pain results when the knee and the thigh bone (femur) rub together. Dull, aching pain, and/or a feeling of grinding when the knee is flexed may occur. Chondromalacia patellae are caused by an irritation of the underside of the kneecap. It may be the result of the simple wear-and-tear on the knee joint as we age. In younger people, it is more often due to an acute injury such as a fall or a long-term overuse injury related to sports.
Unlike the damage to cartilage caused by arthritis, damage caused by chondromalacia can often heal. Conservative treatment is usually recommended first since rest and physical therapy may eliminate the symptoms. First, the inflammation caused by chondromalacia must be allowed to subside. The best treatment for patellofemoral syndrome is to avoid activities that compress the patella against the femur with force. This means avoiding going up and downstairs and hills, deep knee bends, kneeling, step-aerobics and high impact aerobics. Do not wear high-heeled shoes. While nutritional supplements such as glucosamine and chondroitin have been shown to ease arthritic joint discomfort and slow down articular cartilage breakdown in some patients, there is no convincing proof yet that they totally halt or reverse chondromalacia
Other Names
- Chondromalacia Patellae (CMP)
- Chondromalacia of the patella
- Patellar chondral defects
- Idiopathic Chondromalacia Patellae
Pathophysiology
- General: Chondromalacia (Main)
- The undersurface of the patella is covered with hyaline cartilage that articulates with the hyaline cartilage femoral groove
- Chondromalacia is defined by softening and then subsequent tearing, fissuring, and erosion of hyaline cartilage
- Causes include post-traumatic injuries, microtrauma wear and tear, and iatrogenic injections of medication
- Pain generation
- Poorly understood and likely multifactorial
Causes
- Iatrogenic
- Chondrotoxic medications include Corticosteroids
- Overuse
- Majority of chondromalacia is associated with repetitive microtrauma of the patellofemoral hyaline cartilage
- Patella Tracking issues
- Lateralization of the patella
- Tight lateral retinaculum
- Lateral synovial plica
- Patella Alta
- Patella Baja
- Other etiologies that can cause quad atrophy
- Complication of knee trauma
- Immobilization
- Surgical procedures
Pathoanatomy
- Patella
- Posterior surface covered with thick articular cartilage (up to 1 cm)
- Extensor Mechanism: Quadriceps Tendon inserts into Patella, Patella Tendon in turn attaches to Tibial Tubercle
- Patellofemoral Joint: Characterized by the articulation of the patella within the condylar groove of the femur
- Biomechanical
- Abnormal Q Angle
- Pes Planus
- Genu Valgus
- Excessive pronation
- Patella Alta
- Muscle
- Tight Rectus Femoris
- Tight Tensa Fascia lata
- Tight Hamstrings
- Tight Gastrocnemius
- Vastus medialis insufficiency
Differential Diagnosis
- Fractures
- Distal Femur Fracture
- Patellar Fracture
- Tibial Plateau Fracture
- Dislocations & Subluxations
- Patellar Dislocation (and subluxation)
- Knee Dislocation
- Proximal Tibiofibular Joint Dislocation
- Muscle and Tendon Injuries
- Quadriceps Contusion
- Iliotibial Band Syndrome
- Quadriceps Tendonitis
- Patellar Tendonitis
- Popliteus Tendinopathy
- Extensor Mechanism Injury
- Patellar Tendon Rupture
- Quadriceps Tendon Rupture
- Patellar Fracture
- Ligament Pathology
- ACL Injury
- PCL Injury
- MCL Injury
- LCL Injury
- Meniscal Pathology
- Posterolateral Corner Injury
- Multiligament Injury
- Arthropathies
- Knee Osteoarthritis
- Septic Arthritis
- Gout
- Bursopathies
- Prepatellar Bursitis
- Pes Anserine Bursitis
- MCL Bursitis
- Infrapatellar Bursitis
- Patellofemoral Pain Syndrome (PFPS)/ Anterior Knee Pain)
- Chondromalacia Patellae
- Patellofemoral Osteoarthritis
- Osteochondral Defect Knee
- Plica Syndrome
- Infrapatellar Fat Pad Impingement
- Patellar Instability
- Neuropathies
- Saphenous Nerve Entrapment
- Other
- Bakers Cyst
- Patellar Contusion
- Pediatric Considerations
- Patellar Apophysitis (Sinding-Larsen-Johansson Disease)
- Patellar Pole Avulsion Fracture
- Tibial Tubercle Avulsion Fracture
- Tibial Tuberosity Apophysitis (Osgood Schalatters Disease)
Diagnosis
- History
- Patients will complain of anterior knee pain
- Worse with stairs, squatting, kneeling, running, prolonged periods of sitting
- May complain of bucking due to quadriceps inhibition reflex
- Onset is insidious
- Physical Exam: Physical Exam Knee
- Quadriceps muscle atrophy may be present
- Tenderness on palpating under the medial or lateral border of the patella
- Crepitus with a range of motion
- Swelling/ effusion is often mild to non-exist
- Special Tests
- Patellar Grind Test: while supine with the knee extended, apply a posteriorly directed force
- Patellar Apprehension Test: apply medial/lateral pressure while flexing/extending the knee
- Passive Patellar Glide: patella is moved medial/lateral with the knee fixed at 30° flexion
- Patella Alta Test
- Patellar Tilt Test: Attempt to lift lateral aspect of the patella with thumb
- Squat Test: The patient is asked to perform repetitive squats
- Vastus Medialis Coordination Test
- Waldrens Test: Palpate patella while the patient performs squats
- Step Down Test: Eccentric step down from an approx. 20 cm box
- Resisted Isometric Quadriceps Contraction
Radiographs
- Standard Knee Radiographs
- Often normal
- May show signs of Patellofemoral Arthritis
- Findings
- Chondroitin
- Shallow sulcus
- Patella Alta or Patella Baja
- Lateral patellar tilt
MRI
- Findings
- Increased signal in cartilage
CT
- Indications
- Fracture
- Evaluate patellofemoral alignment
- Findings
- Trochlear Geometry
- Tibial-tuberosity to trochlear groove distance (TT-TG distance)
Ultrasound
- Ultrasound is generally not indicated
- It May be used to evaluating other causes of anterior knee pain
Classification
Outerbridge Classification
- Describes the severity of the degenerative process
- As seen on arthroscopy or MRI (fat-saturated sequences)
- Often varied within the same knee
- Level 1
- Softening or swelling of the cartilage
- Arthroscopy: focal areas of hyperintensity with normal contour
- Level 2
- Defined by fibrillation, fragmentation of the hyaline cartilage
- Arthroscopy: blister-like swelling/fraying of articular cartilage extending to surface
- Level 3
- Fissuring of the articular cartilage to the level of subchondral bone, crab-meat appearance
- Arthroscopy: partial thickness cartilage loss with focal ulceration
- Level 4
- Burned bone devoid of articular cartilage covering.
- Arthroscopy: cartilage loss with underlying bone reactive changes
Treatment
Prognosis
- There is no definitive cure for chondromalacia patella
Nonoperative
- Indications
- The vast majority of patients
- General
- In most cases, management mirrors Patellofemoral Pain Syndrome
- There is no universally accepted standard of care
- Physical Therapy
- Emphasis on strengthening glutes, medial quadriceps
- Stretching of quadriceps
- Medications
- NSAIDS, Acetaminophen
- Patellar Brace
- Corticosteroid Injection
- Ice Therapy
- McConnel Taping (Kinesiology Taping)
- Foot Orthosis
- It May be useful to correct pronation, internal rotation of the foot, increased Q angle
Regenerative Therapy
- Mesenchymal Stem Cells
- One study of 3 patients showed benefits up to 1 year[1]
- Platelet Rich Plasma
- Prolotherapy
- One retrospective study showed statistically significant improvement in symptoms among patients[2]
Operative
- Indications
- Refractory cases
- Technique
- Chondral debridement
- Plica release
- Lateral retinacular release
- Patellar realignment surgery
Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices.
