Patellofemoral osteoarthritis is arthritis that affects the joint between the kneecap and the groove at the front of the thigh bone. In simple words, it is wear and degeneration involving the underside of the patella and the trochlear groove where the kneecap moves during bending and straightening.[1] In my practice, I often explain to Bangladeshi patients that this problem usually causes pain in the front of the knee rather than deep pain on the inside or outside of the knee.
This condition can make daily activities surprisingly difficult. Many patients feel more pain while going up or down stairs, rising from a chair, kneeling, squatting, or sitting for a long time with the knee bent.[1][2] In Dhaka and other parts of Bangladesh, this matters a lot because many patients regularly use stairs, sit in crowded transport with bent knees, pray in kneeling positions, or continue household and work duties that repeatedly load the front of the knee.
What Happens in Patellofemoral Osteoarthritis
The kneecap normally glides inside the trochlear groove with the help of smooth articular cartilage. This cartilage acts like a protective low-friction surface.[1] In patellofemoral osteoarthritis, that cartilage gradually becomes worn, frayed, and inflamed. In more advanced disease, the joint space narrows, bone spurs can form, and movement of the kneecap over the femur becomes painful.[1][3]
One important point I want Bangladeshi patients to understand is that arthritis does not always begin as a severe deformity. It often starts as activity-related pain, stiffness, crepitus, and discomfort during movements that place load on the kneecap.
Common Symptoms
The main symptom is pain in the front of the knee, often behind or around the kneecap.[1] Patients may also notice:
- pain while climbing or descending stairs
- discomfort after prolonged sitting with the knee bent
- pain during squatting, kneeling, or rising from a chair
- grinding, crackling, or crepitus
- swelling or stiffness
- reduced walking tolerance
- occasional feeling of weakness or buckling[1][2][3]
AAOS notes that patellofemoral arthritis commonly makes kneeling, squatting, and stair activity difficult.[1] General knee osteoarthritis can also cause clicking, snapping, grinding, stiffness, swelling, and reduced movement.[3]
Why It Happens
Patellofemoral osteoarthritis is not caused by only aging. In many patients, there are underlying mechanical or structural reasons that increase stress on the kneecap joint.
Maltracking and Dysplasia
If the kneecap does not fit or move properly in the trochlear groove, the cartilage experiences abnormal pressure over time.[1] AAOS explains that dysplasia and poor patellar fit in the groove increase stress and gradually wear the cartilage down.[1]
Previous Instability or Dislocation
A history of kneecap instability, subluxation, or dislocation can damage cartilage and change the way load passes through the front of the knee.[4] Over time, that can contribute to patellofemoral arthritis.
Previous Fracture or Trauma
Patellar fractures may heal, but the smooth joint surface may no longer be normal. AAOS notes that this can lead to friction and later arthritis in the patellofemoral compartment.[1]
General Osteoarthritis Risk Factors
MedlinePlus notes that osteoarthritis risk increases with age, excess body weight, prior injuries, and repeated joint loading.[2] Activities or occupations involving repeated kneeling, squatting, climbing, or heavy joint stress may also contribute.[2]
In Bangladesh, these everyday load factors are often important. I see many patients who have to continue physically demanding work long after symptoms begin.
How Patellofemoral Osteoarthritis Differs From Other Knee Problems
Not every front-of-knee pain is arthritis. Some patients with pain around the kneecap actually have:
- patellar maltracking
- patellofemoral pain syndrome
- plica irritation
- meniscus-related symptoms
- tendon-related pain
- inflammatory arthritis
That is why careful diagnosis matters. Patellofemoral osteoarthritis becomes more likely when symptoms are chronic, load-related, associated with stiffness or crepitus, and supported by examination and imaging findings.[1][3]
How I Evaluate This Problem
When I assess a patient with suspected patellofemoral osteoarthritis, I try to understand both the symptoms and the mechanics.
History
I ask:
- where exactly the pain is felt
- whether stairs worsen the pain
- whether there is prolonged-sitting pain
- whether there is crepitus, stiffness, or swelling
- whether there was any previous kneecap dislocation, fracture, or major knee injury
- whether the symptoms are affecting daily function and work
Physical Examination
Clinical examination usually includes checking:
- tenderness around the kneecap
- swelling or joint fluid
- knee range of motion
- patellar alignment and tracking
- crepitus during movement
- gait pattern
- muscle weakness around the thigh and hip[1][3]
Imaging
X-rays are often very useful because they may show narrowing of the patellofemoral joint space, bone spurs, or alignment problems.[1] In selected patients, MRI can help if the diagnosis is unclear or if I need better assessment of cartilage, other compartments of the knee, or associated soft-tissue problems.
Non-Surgical Treatment
Many patients improve without surgery, especially when the condition is recognized early and treated systematically.
