Patellafemoral Pain and Replacement

A New and Better Way to Restore Knee Function and Relieve the Pain of Kneecap Arthritis and Wear

Pain and loss of function from kneecap (patella) arthritis and cartilage wear is a common problem afflicting up to 10 % of the population. Often patients undergo multiple operations only to end up with severe disability.This is because many of the traditional solutions have been shown to have fairly high failure rates averaging 30 %. ( Table 1.) See our further discussion on the surgical alternatives to patellofemoral pain.

In addition,establishing the correct cause of kneecap pain and knowing when to perform any one operation and as importantly knowing what operation not to do is critical to successful treatment.

Table 1. Operative approaches for patellofemoral arthritis

  1. Arthroscopic debridement
  2. Microfracture articular restoration
  3. Lateral release
  4. Soft-tissue realignment of the extensor mechanism
  5. Osteotomies of the tibial tubercle
  6. Mosiacplasty/autologous chondrocyte implantation
  7. Lateral patella partial facetectomy
  8. Patellectomy (removal of the kneecap)
  9. Total knee replacement

What does arthritis of the kneecap look like?
Articular cartilage is that tissue covering the ends of bones where they meet to form a joint (think of the knuckle of a chicken drumstick). That precious layer must remain intact ,smooth,and of a proper thickness or your body weight will not be cushioned and the bending of the joint will feel rough with increased mechanical friction.

Degenerative arthritis (also known as osteoarthritis ) is the type of knee arthritis resulting from accumulative wear and tear or direct trauma damage to that joint surface. Knee cap cartilage damage is also called chondromalacia patella (chondro= cartilage;malacia=softening;patella=kneecap). Whatever the reason,once the joint surface deteriorates, the underlying bone is exposed and pain increases due to the overloading of the many underlying nerves .

If the joint surface cannot be fixed or repaired,then the force of the joint must be reduced or the surface artificially protected (replacement). Normal kneecap x-rayArthritic kneecap x-ray

What are the indications for patellofemoral replacement?
The indications for patellofemoral replacement are summarized in Table 2. While operative replacement of any portion of the knee joint is one of the last options,it is often the only good choice left when other treatments fail of result in increased pain. We have found a definite trend of more rapid recovery,better function, more predictable return to work,and decreased dependency on pain medication with this operation. Patients can become very depressed and socially drained by the stress of constant pain and ineffectual prior treatment. Patellofemoral replacement offers more predictable relief from these problems in our experience.

Table 2. Indications for Patellofemoral Replacement

  1. Degenerative osteoarthritis (ie.loss of joint space with osseous deformation ) limited to the patellofemoral joint
  2. Severe symptoms affecting daily activity referrable to patellofemoral joint degeneration unresponsive to lengthy(3 to 6 months) nonsurgical options and/or failed prior conservative procedures(eg.lateral release,arthroscopic debridement,cartilage transplantation)
  3. Post traumatic osteoarthritis
  4. Extensive Grade 3 chondrosis (ie.loss of joint space without osseous deformation of the patellofemoral,joint space , particularly pantrochlear,medial facet,or proximal half of patella
  5. Failed extensor unloading procedure(eg.Maquet,Fulkerson)
  6. Patellofemoral malalignment/dysplasia induced degeneration with or without instability

Are there any contraindications to patellofemoral replacement surgery?
Yes,some patients cannot have this operation either because they wait too long and their knee is too damaged or they have one of the conditions listed in Table 3.

However,most patients should consider this procedure as a possible option for their patella arthritis and get evaluated before choosing a final solution. It is important to seek a surgeon who has experience with patellofemoral replacement,since opinions vary greatly depending upon the individual surgeon' s own preferences .

Table 3. Contraindications to patellofemoral arthroplasty

  1. No attempt at nonoperative care or to rule out other sources of pain
  2. Arthritis involving the tibiofemoral articulation greater than Kellgren Grade I/ II
  3. Systemic inflammatory arthropathy
  4. Osteoarthritis/chondrosis less than Grade 3/4
  5. Patella infera
  6. Uncorrected patellofemoral instability/malalignment
  7. Uncorrected tibiofemoral mechanical malalignment(valgus>80;varus >50)
  8. Active infection
  9. Evidence of chronic regional pain syndrome
  10. Fixed knee range of motion loss ( -100 ext.-1100 flex.minimum)
  11. Psychogenic pain

What other factors can adversely influence the success of patellofemoral replacement ?
Several other factors have been identifies by our research to affect the success of kneecap surgery and particularly patellofemoral replacement. These are summarized in Table 4.

Table 4. Additional factors that may adversely effect patellofemoral arthroplasty outcome

  1. Multiple antecedent procedures or extensive soft-tissue trauma associated with residual quadriceps atrophy
  2. History of prior arthrofibrosis in the same joint or other operative site
  3. Ligamentous tibiofemoral instability
  4. A post menisectomy knee
  5. Chondrocalcinosis
  6. High patient activity or bent knee use
  7. Age under 40
  8. Unrealistic patient expectations
  9. A surgeon with lack of experience in arthroplasty or extensor mechanism realignment
  10. Obesity(BMI >30)
  11. Patella alta
  12. Primary osteoarthritis
  13. Male gender

What can I do if I have been told I have a bad, wornout,or arthritic kneecap and I have to either live with my pain or accept a total knee replacement ?

Patients are often told that there is nothing more that can be done for them and they must live with the pain or worse accept a must larger and potentially complicated total knee procedure.Many patients are younger than 50 and to live with the pain and disability of kneecap arthritis is not an option.These patients are very intimidated by the choices offered to them especially if their surgeon seems to throw up his hands over their problem. Fortunately, our experience and the overall technological progress with patellofemoral replacement, now provides a better answer.

What does a patellofemoral replacement look like ?
Patellofemoral replacement ("kneecap replacement", patellofemoral arthroplasty) is one type of minimally invasive knee surgery. The parts (components) are very small compared to a standard total knee replacement.

Standard Total Knee Replacement
Note : the much greater size of the components which means a larger portion of the normal knee is sacrificed with greater operative risks and a less natural feeling function. If a total knee operation fails or you experience a complication,the solutions in most cases are more complicated than with a patellofemoral replacement.

Steps you should take to obtain additional opinion about your kneecap problem :
At the Center, patients come from across the United States and the World to seek additional opinions. To get the most out of your visit and achieve proper treatment, you must do the following :

  1. Request a copy of your operative reports and medical records from your previous physician.
  2. Bring copies of any X-rays or MRI's
  3. Write a concise history of your problem and it's treatment
  4. You may contact Dr. Leadbetter at 410-601-BONE (2663) (see appointment section on this web site for further details) or go to our parent web site at
  5. When you call for your appointment,our staff will obtain your insurance information and give you additional help.
  6. Directions to the Center for Joint Preservation and Replacement at Sinai Hospital,Baltimore can be found at