Patellofemoral Knee Arthritis

Patellofemoral knee arthritis affects the joint between the underside of the kneecap and the trochlear groove at the front of the thigh bone. It commonly causes front knee pain during stairs, chair rise, squatting, kneeling and prolonged sitting. Some patients have isolated patellofemoral disease, while others also have medial or lateral compartment arthritis.

Front knee pain is not automatically patellofemoral arthritis. Patellofemoral pain without established arthritis, tendon problems, muscle weakness, kneecap instability, previous trauma and referred pain can produce a similar pattern. Diagnosis therefore requires the symptoms, examination and appropriate imaging to agree.

For the broader symptom differential, read Front Knee Pain.

Quick Answer: What Is Patellofemoral Knee Arthritis?

• Arthritic change affects the underside of the kneecap and the femoral groove

• Pain is commonly felt at the front of the knee or behind the kneecap

• Stairs, chair rise, deep bending and prolonged sitting often provoke symptoms

• Grinding or crepitus may occur, but noise alone does not determine severity

• Dedicated kneecap X-ray views help assess the compartment

• Many patients can be managed without surgery

• Surgery depends on whether disease is isolated or part of wider knee arthritis

How the Kneecap Joint Works

The patella sits within the quadriceps mechanism and glides through the trochlear groove as the knee bends and straightens. It improves the leverage of the thigh muscles. The area of contact and force between the patella and femur changes with knee angle, muscle effort, speed and external load.

Stairs, squatting and rising from a low chair require greater quadriceps force and deeper knee bending than level walking. These activities can therefore reveal symptoms earlier. The presence of pain does not mean that every bend is causing new damage; it indicates that the current task exceeds the tolerance of the joint or supporting system.

What Causes Patellofemoral Arthritis?

• Age-related osteoarthritis and cumulative joint change

• Previous patellar dislocation or recurrent instability

• Previous fracture involving the kneecap or trochlea

• Trochlear dysplasia or abnormal kneecap tracking

• Previous knee surgery or cartilage injury

• Inflammatory or crystal arthritis in selected patients

• Arthritis progressing from or occurring with other knee compartments

Muscle weakness and movement control can increase symptoms but should not be simplistically described as the sole cause of structural arthritis. Pain can also create weakness and altered movement, so assessment should avoid blaming the patient’s technique without considering the joint.

Typical Symptoms and Activity Patterns

Front knee pain

Pain may be felt behind the kneecap, around its edges or diffusely at the front. The exact location is not always precise because patellofemoral pain, tendon pain and general arthritis may overlap.

Stair pain

Descending may be more difficult because the quadriceps must control the body while the knee bends. Climbing requires greater power to lift the body. Pain on stairs is common but not specific to patellofemoral arthritis; weakness, tibiofemoral arthritis and meniscal or tendon problems can contribute.

Pain after prolonged sitting

Some patients develop aching after sitting with the knee bent in a car, theatre, flight or office chair. The first few steps may feel stiff. This pattern is sometimes called the theatre or movie sign, but it can also occur with non-arthritic patellofemoral pain.

Chair rise and low-seat difficulty

A low sofa, toilet or car seat requires greater knee flexion and quadriceps force. Patients may push on the armrests, lean forward or shift to the other leg. Read Knee Pain While Getting Up From a Chair.

Squatting, kneeling and floor sitting

Deep bending increases patellofemoral demand. Difficulty with squatting or cross-legged sitting alone is not an indication for replacement. The clinical importance depends on pain, broader daily function and the activities that matter to the patient.

Grinding, clicking or crepitus

Noise can occur with normal tissue movement, patellofemoral pain or arthritis. Painless crepitus is not proof of severe damage. Grinding accompanied by pain, swelling, loss of movement or functional decline is more clinically relevant.

Patellofemoral Arthritis or Patellofemoral Pain Syndrome?

Patellofemoral pain syndrome

Patellofemoral pain is a clinical pain condition that can occur without established osteoarthritis, often after activity changes or with reduced load tolerance and movement control. It is common in younger adults but also occurs in non-athletes and older people.

Patellofemoral arthritis

Patellofemoral arthritis involves structural degeneration of the patellar and trochlear surfaces. It is more likely when appropriate X-rays show joint-space narrowing, osteophytes and bone changes that fit the symptoms and examination.

The two conditions can overlap. An X-ray abnormality can be incidental, and pain without radiographic arthritis is still genuine. Treatment is based on the complete clinical picture.

Other Causes of Front Knee Pain

• Patellar or quadriceps tendon overload

• Hoffa fat-pad irritation

• Synovial plica or local soft-tissue irritation

• Patellar instability or previous dislocation

• Meniscal or tibiofemoral compartment disease

• Hip or lumbar spine referred pain

• Inflammatory arthritis, gout or infection

How Patellofemoral Arthritis Is Diagnosed

History and examination

Assessment includes pain location, stairs, chair rise, sitting tolerance, squatting, swelling, instability, previous dislocation, trauma, surgery and symptoms in the inner and outer knee. Examination assesses gait, alignment, kneecap tracking, tenderness, crepitus, swelling, movement, quadriceps and hip strength, ligament stability and hip or spine findings.

X-rays

Standing front and side X-rays assess the rest of the knee. A dedicated patellofemoral or skyline view helps show joint-space narrowing, tilt, osteophytes and the relationship between the patella and trochlea. The entire knee must be reviewed because arthritis outside the patellofemoral compartment changes surgical options.

MRI

MRI is not routinely required when the symptoms, examination and X-rays provide a clear diagnosis. It may be useful when the X-rays are inconclusive, cartilage or soft-tissue injury is suspected, instability requires further definition or the result is likely to change treatment.

Non-Surgical Treatment

Activity modification without complete avoidance

During a flare, temporarily reduce repeated deep squats, painful stairs, prolonged kneeling or high-load exercises. Use a railing, divide stair trips and choose a higher chair when needed. The long-term goal is safe capacity and useful activity, not permanent avoidance of all knee bending.

Therapeutic exercise

A programme may include quadriceps and hip strengthening, movement control, knee and hip mobility, balance and gradual exposure to stairs or chair rise. Exercise should be progressed rather than repeatedly forced through escalating pain or swelling. Initial discomfort does not necessarily mean harm, but persistent substantial flare requires adjustment.

Weight management and medicines

For people living with overweight or obesity and osteoarthritis, sustainable weight reduction can improve pain and function. Topical or oral pain medicines may support activity after considering stomach, kidney, heart, liver and medication risks.

Taping, braces and footwear

Taping or a brace may help selected patients with pain or tracking-related symptoms, but neither is a permanent structural cure. Footwear should be comfortable and secure. No insert can replace assessment when symptoms are persistent or progressive.

For the complete pathway, read Non-Surgical Knee Arthritis Treatment in Mumbai.

What Role Do Injections Have?

A corticosteroid injection may provide short-term relief for selected osteoarthritis patients, particularly when pain or swelling prevents rehabilitation. Evidence and recommendations differ for hyaluronic acid, PRP, GFC and other injections. The response depends on diagnosis, arthritis distribution, stage and patient factors.

No injection can guarantee cartilage regeneration, correct significant maltracking or permanently prevent surgery. An injection should not be used as a substitute for assessing instability, widespread arthritis or another source of front knee pain.

When Is Surgery Considered?

Surgery is considered when structural disease is clearly defined, symptoms and functional loss are substantial, appropriate non-surgical treatment is ineffective or unsuitable, and the expected benefit justifies the risks. The operation depends on whether disease is isolated to the patellofemoral compartment or affects the rest of the knee.

Option A: Patellofemoral replacement

Patellofemoral replacement is a compartment-specific procedure that resurfaces the patella and trochlear groove while preserving the medial and lateral compartments. Careful selection is essential. The clinically important arthritis must be isolated to the patellofemoral compartment, and the remaining joint, ligaments, alignment, tracking, movement and patient factors must be suitable.

A disadvantage is that arthritis may later progress in the unreplaced compartments, potentially requiring further surgery. Significant stiffness, ligament damage, major deformity, inflammatory arthritis, crystal arthritis or poor tracking may make this procedure unsuitable.

Option B: Total knee replacement

Total knee replacement is more commonly considered when clinically important arthritis extends into the medial or lateral compartments, when deformity is substantial, when isolated patellofemoral replacement is unsuitable or when the broader knee pattern requires resurfacing.

Which option is better?

Neither is universally better. Patellofemoral replacement preserves more of the native knee but has narrower indications and can be affected by progression elsewhere. Total replacement treats wider disease but resurfaces more of the joint. The correct choice follows the complete disease pattern and informed patient preference.

What Robotic Assistance and the Mini-Subvastus Approach Mean

Robotic assistance is relevant only after the decision for a suitable replacement procedure has been made. It can support planning and execution in selected operations, but it does not diagnose patellofemoral arthritis, decide the correct procedure or operate independently.

Dr. Mayur Rabhadiya’s standard total-knee-replacement positioning combines robotic planning with a minimally invasive mini-subvastus, muscle-sparing approach when clinically suitable. The robot concerns planning and execution; the mini-subvastus approach concerns how the surgeon accesses the joint. Neither guarantees painless surgery, rapid recovery or a particular flexion result.

Warning Signs That Need Prompt or Urgent Assessment

• A sudden patellar dislocation or visible deformity

• Inability to bear weight after a fall, twist or direct injury

• A hot, red and rapidly swollen knee, especially with fever

• True locking or inability to straighten the knee

• Repeated kneecap instability, buckling or falls

• Sudden calf swelling, chest pain or breathlessness

Questions Patients Commonly Ask

Why are stairs painful with patellofemoral arthritis?

Stairs require greater quadriceps force and knee bending, which increases demand through the patellofemoral joint. Weakness and movement control can further influence symptoms.

Why is going downstairs often worse?

Descending requires the quadriceps to control the body while the knee bends. Patellofemoral load, weakness, balance and fear of falling may all contribute.

Does grinding mean the cartilage is completely gone?

No. Crepitus can occur with normal tissue movement, patellofemoral pain or arthritis. Its importance depends on pain, swelling, function and imaging.

Can patellofemoral arthritis occur without tibiofemoral arthritis?

Yes. Arthritis can be isolated to the kneecap compartment, although the medial and lateral compartments must be assessed carefully.

Can young adults have patellofemoral arthritis?

Yes, particularly after instability, fracture, cartilage injury or abnormal trochlear anatomy. Many young adults with front knee pain have patellofemoral pain without established arthritis, so diagnosis matters.

Can strengthening wear out the kneecap faster?

Appropriately dosed quadriceps and hip strengthening is commonly used to improve load tolerance and function. The exercise range and load should be modified when symptoms repeatedly flare.

Should I avoid all squats and stairs?

Not necessarily. Temporary reduction may be useful during a flare, followed by graded exposure. The appropriate range and volume depend on symptoms and goals.

Do I need an MRI?

Usually not when the diagnosis is clear from examination and appropriate X-rays. MRI is used when it is likely to answer a specific question and change treatment.

Can injections repair kneecap cartilage?

No injection has been established as a guaranteed method to restore normal established patellofemoral cartilage. Selected injections may provide temporary symptom relief.

Does patellofemoral arthritis always require knee replacement?

No. Many patients are managed non-surgically. Surgery is considered only when symptoms and functional loss remain substantial and the disease pattern supports a suitable procedure.

What is patellofemoral replacement?

It is a compartment-specific partial replacement that resurfaces the patella and trochlear groove while preserving the remaining knee. It is suitable only for carefully selected isolated disease.

Why might patellofemoral replacement later need another operation?

Arthritis can progress in the medial or lateral compartments, or another problem may develop. Some patients may later require conversion to total knee replacement.

When is total knee replacement preferred?

It is more appropriate when clinically important arthritis affects other compartments, when deformity or stiffness is substantial, or when isolated patellofemoral replacement is unsuitable.

Can robotic assistance decide which replacement I need?

No. Procedure selection is a clinical decision made by the surgeon and patient. Robotic assistance may support planning and execution after the operation has been chosen.

Clinical References and Further Reading

AAOS OrthoInfo: Patellofemoral Pain Syndrome

AAOS OrthoInfo: Patellofemoral Replacement

NICE NG226: Osteoarthritis in over 16s—diagnosis and management

AAOS: Management of Osteoarthritis of the Knee Clinical Practice Guideline

About Dr. Mayur Rabhadiya

Dr. Mayur Rabhadiya is an Orthopedic and Joint Replacement Surgeon in Mumbai. His focused knee practice includes diagnosis-first evaluation, stage-wise knee arthritis care, selected non-surgical treatment and minimally invasive mini-subvastus robotic knee replacement when clinically indicated. His qualifications are MBBS, D’Ortho, DNB (Orthopedics), MNAMS (Orthopedics) and FIJR (Robotic & Navigation).

Last medically reviewed: 24 July 2026. Medical reviewer: Dr. Mayur Rabhadiya.

Book a Front-Knee-Pain or Arthritis Assessment in Mumbai

Patients with persistent front knee pain, stair difficulty, painful chair rise, kneecap grinding or uncertainty about patellofemoral surgery can consult Dr. Mayur Rabhadiya in Ghatkopar East or Ghatkopar West, Mumbai. Bring current and previous X-rays, MRI scans, prescriptions and operation records when available. Call or WhatsApp +91 84249 03913 or +91 96113 30063, or use the orthopedic appointment page.

Medical Disclaimer

This guide is for general education and does not replace an individual clinical assessment. Front knee pain and suitability for patellofemoral or total knee replacement depend on symptoms, examination, medical history and appropriate imaging. Seek urgent care for severe injury, inability to bear weight, a hot swollen knee with fever, patellar dislocation, true locking, sudden calf swelling, chest pain or breathlessness.