Patellofemoral Pain Syndrome and chondromalacia patella
Ross Hauser, MD
In this article, we will explore the various treatment options that can help people today with chondromalacia patella, patellofemoral pain syndrome, or “runner’s knee” get back to their sport or activities. We will discuss the various causes of a traumatic knee injury, degenerative arthritis, sudden onset from overtraining, and the development of the pain syndrome following arthroscopic knee surgery.
- At some point, you decide that you can no longer manage this pain on your own with over-the-counter pain relief medications, knee braces, and ace bandages so you go to a health care provider.
- I do not understand what my at my problem is. “No matter what you call it, you have pain.”
- Doctors are more aware that patellofemoral pain is a confusing diagnosis.
- The many problems in the knee that surround a patella diagnosis.
- A pain that no one understands and in some cases, no one believes.
- This study’s aim was to “determine whether the evidence supports manifestations of central sensitization in individuals with Patellofemoral pain. (Simply, is this real?)
- Intent to study neurophysiological changes of brain and spinal cord in individuals with patellofemoral pain.
- Patellofemoral Pain Syndrome – Why women feel more pain.
- You may be surprised that the health care provider is recommending the same over-the-counter pain medications and knee braces and other knee pain , treatments you tried on your own that did not work for you.
- Physical therapy will typically fail if the strong connective ligament and tendons needed to provide resistance to maximize muscle gain and knee stability are not strong enough.
- Exercise can work in some with Patellofemoral pain
- Using painkillers – Doctors issue concerns and warnings – Approximately one in five adolescents with longstanding knee pain reported pain medication use.
- Patients waiting for an MRI delay exercise and physical therapy while waiting outcomes. Some researchers say this is no good.
- The MRI will not see your knee pain getting worse and it will confuse you and your doctor.
- Will a knee brace or tape hold my knee together, even with “appropriate caution?”
- Retraining the way you run? A new study kicks off to explore gait training.
- “The patient often bounces from practitioner to practitioner, physiotherapist as well as surgeon, for some relief of symptoms.”
- When knee pain is worse than it should be and nothing is working, what next?
- Hip and knee strengthening (physical therapy and exercise) may not be adequate to heal the problem. Are they actually making it worse? Especially in women?
- Patellofemoral pain syndrome impacts the whole body.
Surgery and other treatments
- Patellofemoral cartilage surgery?
- Research: Unrealistic expectations of patella pain syndrome surgical success are common and will lead to disappointment.
- The prevalence and change in neuropathic pain or pain catastrophizing before and 12 months following patellar stabilization surgery for patellofemoral instability
- “This rise in surgical intervention has brought about various complications.”
- Younger patients have better surgical results, but what do you do with older patients? Patellofemoral arthroplasty?
- Botulinum toxin injections as a salvage therapy.
- Solving Patellofemoral Pain Syndrome is recognizing the problem of knee instability.
- You must treat the whole knee to fix the problem of patella pain.
- Comprehensive Prolotherapy for Patellofemoral Pain Syndrome – treating the whole knee.
- Platelet Rich Plasma Therapy.
- Discussion of stem cell therapy.
You started experiencing knee pain, your kneecap is sliding out of place, you can no longer exercise or walk down a flight of stairs without pain. You need help.
Above I discussed the various ways your knee pain may have developed. Over the years we have heard many stories and case histories from people about their knee pain and have been able to provide a composite view of the challenges many people face.
If you are like the many patients we see, you started experiencing knee pain and that pain became the first step in a long journey of treatments. At first, it was not quite a sharp pain but rather a chronic dull pain that seemed to center on the front of your knee around the knee cap. Then it started to get worse and it started to affect the way you move, work, and participate in sport or exercise.
- If you are athletic, run, and work out, you may have suffered a spike in pain and discomfort especially after running or playing in sports involving jumping. Especially if you are running downhill. You will also notice the same pain when walking down a flight of stairs, The key to your pain seems to be when you are moving downward.
- You may have suffered a spike in pain during exercises involving the use of “squats.”
- Pain may have become intense if you decide to drastically change your sports activity or exercise to be “more challenging.” At some point, intensive workouts or running had to be stopped.
- You feel as if your kneecap slides around too much.
- Younger athletes, too young to have severe osteoarthritis, may have some upper and outer knee pain and they will seek physical therapy. This is a clue of kneecap instability. In this case, physical therapy is being used to strengthen the surrounding muscles, the quadriceps, to keep the knee cap correctly tracking. These younger athletes are in our office because physical therapy is not helping as much as they need it to.
You may have been suggested to exercise and get physical therapy, and were told this will probably help you. You may have been the person that it did not help. Your story may go something like this:
I have chondromalacia patella. It has been bothering me for a year and a half. I have been doing the strengthening exercises that were recommended to me but I am not getting results or relief from the pain. At first, it was only my left knee that was the problem. Now I have swelling and discomfort in my right knee too. My situation is getting worse day by day. I have pain when I walk long distances or stand still for a while. I have avoided all my sports activities. All of this occurred when I started to run long distances on the treadmill.
What would we do in a case like this? This is explained below.
But I am not an athlete, it hurts just the same:
- In non-athletic patients, a vicious cycle may have started. You had knee pain and the knee pain makes you sit for prolonged periods of time.
- The pain is getting worse and your sitting becomes much more frequent. When you try to get up from a chair your knee pops and cracks and there can be intense pain on standing. You sit back down.
- Your situation is in a downward spiral of intense and frequent knee pain. Worse, your doctor may not believe how bad your knee hurts. See below.
The development of Patellofemoral Pain Syndrome after arthroscopic knee surgery will be discussed below.
What are we seeing in this image? A source of knee pain.
This simple illustration may explain a lot of complex pain. On the left, we have a normal knee joint. On the right, we see inflamed chondral cartilage, the cartilage of the back of the knee cap, and in the knee groove where the knee cap is supposed to slide.
At some point, you decide that you can no longer manage this pain on your own with over-the-counter pain relief medications, knee braces, and ace bandages so you go to a health care provider.
You may have a discussion with your healthcare provider, in this discussion, he/she may discuss with you chondromalacia patella. (Chondro means cartilage, malacia means breakdown, and patella means kneecap.) Thus, chondromalacia patella refers to cartilage breakdown underneath the kneecap. Your health care provider may also call this, patellofemoral dysfunction or patellar-tracking dysfunction. If your pain is severe, he/she may discuss with you Patellofemoral Pain Syndrome. If you are an athlete, your clinician may call your condition “runner’s knee,” which is simply a broad description of knee pain that is coming from the knee cap area attributed to overuse.
Whatever it is called, this problem you have is a problem that began as a patellar-tracking problem. You are having pain when the underside of the kneecap is abnormally rubbing against the thigh bone.
I don’t understand what my problem is. “No matter what you call it, you have knee pain.”
People who have patella-related pain are sometimes confused by diagnosis, treatment plan, and a general understanding of what is going on in their knee. Their frustration in multiple diagnoses and a lot of testing is in fact displayed in the statement, “whatever you call it, I have pain.”
A study in the journal Clinics in Sports Medicine (1) offered this challenge to doctors and patients in understanding problems of the knee centered on the patella.
“Patellofemoral pain syndrome is a frequently encountered overuse disorder that involves the patellofemoral region and often presents as anterior (front) knee pain. Patellofemoral pain can be difficult to diagnose. Not only do the etiology, diagnosis, and treatment remain challenging, but the terminology used to describe Patellofemoral pain is used inconsistently and can be confusing. Patellofemoral pain syndrome (PFPS) seems to be multifactorial, resulting from a complex interaction among intrinsic anatomic and external training factors. Although clinicians frequently make the diagnosis of Patellofemoral pain syndrome, no consensus exists about its etiology or the factors most responsible for causing pain.”
That study was published in 2010 and reflects a problem in 2010. Certainly, things have changed in eleven years. Perhaps what has changed is that doctors are more aware that Patellofemoral pain is a confusing diagnosis. But confusion is still there in 2022 as we will see below.
Doctors are more aware that Patellofemoral pain is a confusing diagnosis
In 2017, building on this theme, of difficulty in diagnosis and difficulty in understanding how to stop the progression of knee deterioration and provide treatment, doctors wrote in the Open Access Journal of Sports Medicine,(2) of the problems that need to be recognized in athletes.
“Patellofemoral pain is a very common problem in athletes who participate in jumping, cutting, and pivoting sports. Several risk factors may play a part in the pathogenesis of Patellofemoral pain. Overuse, trauma, and intrinsic risk factors are particularly important among athletes. Physical examination has a key role in Patellofemoral pain diagnosis. Furthermore, common risk factors should be investigated, such as hip muscle dysfunction, poor core muscle endurance, muscular tightness, excessive foot pronation, and patellar malalignment. Imaging is seldom needed in special cases. Many possible interventions are recommended for patellofemoral pain management. Due to the multifactorial nature of patellofemoral pain, the clinical approach should be individualized, and the contribution of different factors should be considered and managed accordingly. In most cases, activity modification and rehabilitation should be tried before any surgical interventions.”
In April 2022, a paper in the journal Musculoskeletal science & practice (35) lead by researchers in Queen Mary University London showed that little by way of understanding patellofemoral pain had been made and that doctors were relying on best hope treatments. This is what they wrote:
“Patellofemoral pain is common and has a poor long-term prognosis. There is a lack of clarity about the clinical reasoning of recognized inter-disciplinary experts in the published literature.”
What they are saying is that patellofemoral pain do not have a clear path of treatment. The best treatment plan involves (according to a survey of 19 clinical experts with about 19 years of experience from different medical specialties) the following:
- First, the assessment and diagnosis process should include a thorough history and examination to rule in Patellofemoral pain.
- Secondly, information provision should aim to increase patients’ understanding, aid in controlling symptoms, and facilitate behavior change.
- Thirdly, active rehabilitation, which was a salient theme and included advocacy of combined hip and knee exercise that is adapted to the individual.
- Finally, treatment adjuncts, which can be used selectively to modify symptoms, may include running retraining, taping, or foot orthoses.
We will discuss these treatments below.
The many problems in the knee that surround a patella diagnosis
Typically a patient with knee problems will include among the problems just mentioned in the above research study, other problems including a meniscus tear, knee bursitis, developing osteoarthritis along with a patella diagnosis in their medical history. They will also have, in many cases, a corresponding treatment program for each individual problem.
Other patients we see will simply report that want to be treated for “patellofemoral syndrome,” or “chondromalacia in my patella.” Usually, they contact us after conservative treatments and physical therapy have not helped enough. Sometimes they even contact us after a surgery such as a patella debridement, a tibial tubercle osteotomy, or a patellofemoral ligament reconstruction were tried. (We discuss these procedures below). So their medical history up until the point of contacting our center is one of continued and in some cases severe knee pain, chronic knee swelling, walking difficulties, problems walking up and downstairs, and the near or total inability to run or jump.
A knee pain that no one understands and in some cases, no one believes
Sometimes people will report pain that no one understands and in some cases, no one believes. While we will discuss this at length below, we want to touch on a November 2020 study (3) here to highlight and address this problem.
In this study, researchers at the University of Wisconsin-Milwaukee, Concordia University Wisconsin, and Marquette University outlined the problems of “more pain than the patient with patella disorder should have,” and what may cause it.
- Patellofemoral pain has high recurrence rates and minimal long-term treatment success.
- Central sensitization (heightened pain) occurs when the nervous system, nociceptive neurons (nerve sensation cells) become hyper-responsive.
This study’s aim was to “determine whether the evidence supports manifestations of central sensitization in individuals with Patellofemoral pain. (Simply, is this real?)
- “Strong evidence supports lower local and remote pressure pain thresholds, impaired conditioned pain modulation, and facilitated temporal summation in individuals with Patellofemoral pain compared to pain-free individuals.” (These people do have heightened pain).
- Conflicting evidence is presented for the heat and cold pain thresholds.
- Pain mapping demonstrated expanding pain patterns associated with long Patellofemoral pain symptom duration. (it spreads)
Intent to study neurophysiological changes of brain and spinal cord in individuals with patellofemoral pain
Research has shown that chronic pain changes brain function. Research also suggests that patellofemoral pain can significantly alter brain function as demonstrated by the above research on Central sensitization (heightened pain). In July 2021 (4) researchers announced their intent to study neurophysiological changes of brain and spinal cord in individuals with patellofemoral pain. This is what the research authors wrote: “Reduced neuromuscular control due to altered neurophysiological functions of the central nervous system has been suggested to cause movement deficits in individuals with patellofemoral pain (PFP). However, the underlying neurophysiological measures of the brain and spinal cord in this population remain to be poorly understood. ” The intent of this research is to understand it better.
Patellofemoral Pain Syndrome – Why women feel more pain
In April 2017, Brazilian and English researchers combined to publish research in the Journal of Science and Medicine in Sport suggesting a serious problem for female runners.
- Women who had a lower pain threshold in their knees found themselves with heightened pain throughout their bodies.
- Additionally, this heightened pain, which is related to self-reported knee function, appears to be increased by greater running volumes. (24)
We touched on this briefly above, overtraining, physical therapy, the continuance of running may make for more pain than the damage should be creating.
A combined research team from the University of Kentucky and the University of Iowa wrote in the Clinical Journal of Pain:
- Little is understood of how pain processing is changed with Patellofemoral Pain Syndrome and how a patient can suffer from hyperalgesia or hypoesthesia (a reduced sense of pain) and what type of alterations to natural knee movement can cause these changes.
In their study, the researchers looked at twenty females diagnosed with Patellofemoral Pain and 20 age-matched pain-free females participated in this study. What they found was the frontal plane knee angle (an unnatural knee alignment) existed in the Patellofemoral Pain group which was not present in the control group.
- This suggested that Patellofemoral Pain Syndrome is characterized by an increase in both localized and centralized pain sensitivity that is related to movement mechanics. Knee pain and knee instability caused greater and heightened pain. (25)
In March 2022 doctors writing in the Journal of sport rehabilitation (37) evaluated brain activity during experimental knee pain and its relationship to kinesiophobia in patients with patellofemoral pain. They were looking specifically at young females. What they found was greater kinesiophobia was positively associated with greater brain activity and associated with alterations in central nociceptive processing.
What are we seeing in this chart? You cannot grow knee cartilage in ibuprofen
The simple explanation of this chart is that researchers took dog cartilage cells and tried to grow more cartilage in an ibuprofen solution to test the effect of ibuprofen on cartilage. What did they find out? Ibuprofen reduced the concentration of cartilage glycosaminoglycan. It reduces cartilage growth.
So what do you do about it? You may be surprised that the health care provider is recommending the same over-the-counter pain medications and knee braces and knee pain treatments you tried on your own that did not work for you.
Some patients report the frustration of going from specialist to specialist and still getting the same recommendations for treatment, or better understood as “pain management,” that has not worked for them before and is in fact part of the reason they are going from specialist to specialist.
Suggested treatments that you may be recommended over and over.
- RICE and PRICE
- The RICE Protocol is Rest, Ice, Compression, and Elevation
- The PRICE Protocol adds Protection (brace or cast), Rest, Ice, Compression, and Elevation
- For many athletes, a doctor’s recommendation of the RICE protocol for healing their sports-related soft tissue issue injury was seen as the gold standard of care. However, this treatment is now under criticism. Please see our article for why we do not typically recommend RICE or PRICE.
- NSAIDs are also something we would not typically recommend as chronic non-steroidal anti-inflammatory drugs (NSAIDs) usage can make the pain worse in the long term. Please see our article, When NSAIDs make the pain worse. Regardless, you may have tried to give these treatments one more chance. When they continue to fail, then you decide something more needs to be done. You get a prescription for physical therapy.
Physical therapy? Physical therapy will typically fail if the strong connective ligament and tendons needed to provide resistance to maximize muscle gain and knee stability are not strong enough.
What are we seeing in this image?
The patella is pulled and pushed in all directions. It is pulled by the Iliotibial band, it is stabilized in place by the lateral patellar retinaculum and the medial patellar retinaculum. The quadriceps move the patella upwards, the patellar ligament moves it downward. When one of these structures is weakened or damaged through degenerative wear and tear, the knee cap becomes unstable.
Physical therapy is a very appealing option because it is exercise and people believe exercise is always beneficial. If you are reading this article physical therapy has likely failed you as well.
- Physical therapy includes leg extensions and stretching exercises to help strengthen the thigh muscle, so the patellae or kneecap, tracks better on the femur – it doesn’t scrape the thigh bone.
- Physical therapy seeks to strengthen the quadriceps as these muscles are the main stabilizers of your kneecap. Physical therapy will have limited or no success if the quadriceps tendon, the tendon that connects the “quads,” the vastus lateralis, vastus medialis, vastus intermedius, and the rectus femoris muscles to the knee cap are weakened. For physical therapy to work, there must be some resistance between muscle and bone. If the quadriceps tendon is damaged, injured, stretched, or harmed in a significant way, physical therapy will have limited if no success.
- Physical therapy will also not work if the ligaments of the knee are compromised or weakened. Ligaments, such as the anterior cruciate ligament (ACL), Medial Collateral Ligament (MCL), Posterior Cruciate Ligament (PCL), hold the knee together by connecting the bones.
- Muscle-strengthening exercises may improve the relative location of the patella upon movement, but do not improve the tendons, ligaments, or cartilage.
Physical therapy will typically fail if the strong connective ligament and tendons needed to provide resistance to maximize muscle gain and stability are not strong enough. We will address this problem and offer our evidence for regenerative medicine injections to correct this problem below.
Exercise can work in some
Doctors at the School of Sport and Exercise Sciences, Liverpool John Moores University examined the effectiveness of exercise in patients in 27 patients with patellofemoral pain. To see if the exercise program was effective they looked for pain reduction, improvement in function, a reduction in kinesiophobia (our fear of movement) among signs that symptoms were getting better.
These are the results they published in the journal Physical Therapy in Sport (5) July 2021. “The results of this study demonstrate that the current exercise recommendations can improve function and kinesiophobia and reduce pain and atherogenic muscle inhibition (a weakness or atrophy in the quadriceps muscle) in individuals with patellofemoral pain. There is a need for reconsideration of the current exercise guidelines (look for more aggressive exercise types) in stronger individuals with patellofemoral pain.
In November 2021, doctors writing in The Journal of the Pakistan Medical Association (6) examined the effects of tibiofemoral (thigh-shin articulation or bend) joint mobilization on pain and range of motion in patients with patellofemoral pain syndrome. In this paper, doctors found “Tibiofemoral joint mobilizations with hip and knee stretching and strengthening exercises were found to be more effective in reducing pain, and increasing range of motion as well as pressure pain threshold. ”
Using painkillers – Doctors issue concerns and warnings – Approximately one in five adolescents with longstanding knee pain reported pain medication use.
A December 2021 study from Aalborg and Southern Denmark Universities in Denmark published in the medical review Scandinavian Journal of Pain (7) has doctors expressing concerns that “the prevalence of pain medication use for adolescent knee pain and factors associated with use are not well understood.” In other words, there is a problem specifically in adolescents (age 10-19) with longstanding knee symptoms.
- In this paper 323 adolescents (73% female), 84% had patellofemoral pain (peri- or retro-patellar pain during loaded bending of the knee).
- Twenty-one percent of adolescents reported pain medication use for their knee pain.
- Adolescents with patellofemoral pain reported greater usage than their counterparts with Osgood-Schlatter Disease.
“whether pharmacological therapy is the best pain management option at this young age is debatable”
Conclusions: “Approximately one in five adolescents with longstanding knee pain reported pain medication use, particularly in adolescents with patellofemoral pain. Knee-related symptoms most consistently associated with the use of pain medications in this population . . .Self-reported pain medication use is common in adolescents with longstanding knee pain, even though whether pharmacological therapy is the best pain management option at this young age is debatable. Reliance on pain medication at an early age could potentially hamper the development of healthy pain coping strategies and increase the risk of dependence and misuse later in life.”
Patients waiting for an MRI delay exercise and physical therapy while waiting outcomes. Some researchers say this is no good
In July 2021 doctors at the Science in Physical Therapy, Bellin College, The University of Newcastle, Tufts University School of Medicine, and Baylor University say routine knee radiographs should be discouraged for individuals with non-traumatic knee pain, but they are often still ordered despite limited evidence for their value in guiding treatment choices. Writing in the PM & R: The Journal of Injury, Function, and Rehabilitation, (8) they further suggest: “Radiograph utilization may delay the use of physical therapy, which has been associated with improved outcomes. . . The research concludes: Routine use of radiographs for PFP is not warranted, and can potentially delay appropriate treatment.”
The MRI will not see your knee pain getting worse and it will confuse you and your doctor
When we talk about MRIs it is often best to listen to radiologists and the surgeons that rely on the MRI for surgical or non-surgical recommendations. In 2012 Doctors at the Finish Institute of Military Medicine published research (9) that found that MRI was ineffective in helping doctors determine the extent of injury in instances of chondromalacia patellae.
In 2018, as well as in 2020, the problem remained. In The Eurasian Journal of Medicine, (10) doctors in Turkey announced: “as chondromalacia stage advances, the symptom severity worsens and knee functions decline; however, MRI measurements do not show the difference between early and advanced stage chondromalacia patella patients.”
Will a knee brace or tape hold my knee together, even with “appropriate caution?”
In physical therapy, strong connective ligaments and tendons are needed to provide resistance. In normal everyday movement, strong connective ligaments and tendons are needed to hold the knee stable and together. Some believe an external brace or tape may help do this job:
Research in the medical journal Joints, (11) suggests that you may benefit from a knee brace or some type of elastic knee sleeve for your patella-related knee pain and help you return to your sport. Many of you reading this article are probably behind a knee brace or sleeve helping.
Doctors at Queen Mary University of London wrote in the medical journal Sports Medicine (12) that doctors “with appropriate caution” should consider brace and taping:
- Offer taping for those patients with greater pain,
- Offer orthoses (knee braces) for older individuals and exercise for younger individuals, and
- Offer orthoses (foot inserts) intervention for patients with greater forefoot and rearfoot abnormalities.
Why the caution? Because there is no good evidence that these treatments work for everyone. Further taping and bracing provide a false sense of stability and can lead to greater knee damage.
Knee braces do provide relief from fear
Some people will need a knee brace but it may be more of a physiological than functional need. In April 2020, researchers published in the Archives of Physical Medicine and Rehabilitation (13) the outcomes of people with patellofemoral pain wearing a knee brace for two weeks compared to a group of people who had patellofemoral pain and did not wear a knee brace for two weeks. Results found that knee braces reduced kinesiophobia (fear of movement) in people with patellofemoral pain after two weeks of wearing one and at a six-week follow-up. The researchers concluded that “a knee brace may be considered within clinically reasoned paradigms to facilitate exercise therapy interventions for people with Patellofemoral Pain.” In other words, if the knee brace gives them the confidence to exercise, that would be okay.
Retraining the way you run? A new study kicks off to explore gait training
In May 2021 researchers announced their intent to study the effectiveness of gait training in patients with Patellofemoral pain. (14) Here is the rationale for this study.
“Patellofemoral pain (PFP) is highly prevalent in runners. Physical therapies were proved to be effective in the treatment of Patellofemoral pain. Gait retraining is an important method of physical therapy, but its effectiveness and safety for Patellofemoral pain remained controversial. The previous review suggests gait retraining in the treatment of Patellofemoral pain warrants consideration. However, recent publications of randomized controlled studies and case series studies indicated the positive effect of gait retraining in clinical and functional outcomes, which re-raise the focus of gait retraining.
(The study’s aim) is to publish findings that will provide information about the safety of gait retraining and their effect on relieving pain and improving the function of the lower limb on runners with Patellofemoral pain.
The interest in gait retraining is summarized in a December 2019 study in The American Journal of Sports Medicine (15). This study investigated whether a 10% increase in the running step rate influences frontal-plane kinematics of the hip and pelvis as well as clinical outcomes in runners with Patellofemoral pain.
- Gait retraining consisted of a single session where the step rate was increased by 10% using an audible metronome.
- After gait retraining, significant improvements in running kinematics and clinical outcomes were observed at 4-week and 3-month follow-up.
- These improvements were maintained at a 3-month follow-up. It is important to assess for aberrant running kinematics at baseline to ensure that gait interventions are targeted appropriately.
“Unsatisfactory long-term prognosis of conservative treatment of patellofemoral pain syndrome”
Why consider these treatments if your chances are 1 in 4 that they will work for you and less that they will get you back to your sport?
In 2018, these same researchers made clear in the journal Physical Therapy in Sport (16) that: “Long-term (traditional) treatment outcomes of (Patellofemoral pain) are poor, with estimates that more than 50% of people with the condition will report symptoms beyond 5 years following diagnosis. Additionally, emerging evidence indicates that PFP may be on a continuum with patellofemoral osteoarthritis.”
So why are these things not working? The heading above is the title of a research paper from Danish researchers published in the Journal of the Danish Medical Association. (17)
- In this study, the Danish team looked at military personnel, athletes, and the general public to offer doctors a clue to how well or unwell conservative treatments work for patellofemoral pain syndrome.
- Only 29% of soldiers,
- Only 27.8% of sports-active and
- Only 24,7% of the general public will become pain-free after they are diagnosed with patellofemoral pain syndrome.
- 21.5% of sports-active and 23% of the general public diagnosed with patellofemoral pain syndrome will stop participating in sports because of knee pain.
These are very low numbers. Why consider these treatments if your chances are 1 in 4 that they will work for you and less that they will get you back to your sport?
As mentioned above, supportive knee braces, arch supports, and taping may also be recommended to improve the alignment of the kneecap. The problem with this approach is that they do not repair the deteriorated cartilage in the patellae.
Unexplained and significant elevation in knee pain that your doctor may not believe
Something is going on beyond normal biomechanical problems
Your doctor is looking at your MRI. Your knee does not look worse. But your pain is. You are confusing your health care providers as nothing seems to work for you. Maybe this is “all in your head?” because it is not on your MRI.
You may also be researching for your son or daughter who is confusing their doctors with a description of elevated pain that “should not be there.”
Doctors writing in the journal Physical Therapy in Sport, (18) wrote that what your son or daughter is trying to describe as heightened pain, is real. Read this:
“Adolescent athletes presented higher levels of pain and lower physical function status compared with physically active non-athletes. This provides an important insight into the management of (Patellofemoral Pain Syndrome) in adolescent athletes as the worst functional status is linked with poor prognosis in patients with Patellofemoral Pain Syndrome.”
Something is causing more pain in the athletes than the non-athletes.
“The patient often bounces from practitioner to practitioner, physiotherapist as well as surgeon, for some relief of symptoms”
Physiotherapist Jenny McConnell wrote in the medical journal Manual Therapy:(19)
“Although the management of Patellofemoral Pain has improved greatly, there is still a category of patient who tends to have recalcitrant (non-responsive) symptoms, which are difficult to manage. The patient often bounces from practitioner to practitioner, physiotherapist as well as surgeon, for some relief of symptoms. However, often the underlying source of the pain is not well understood, so treatment can aggravate the symptoms.”
When knee pain is worse than it should be and nothing is working, what next?
Leading university researchers in the United Kingdom and Denmark, working within the UK’s National Health Services at Derby, made some observations of the patient’s mindset in regard to his/her diagnosis of Patellofemoral Pain Syndrome. (20) These published 2018 findings are similar to what we see in patients here at Caring Medical. Something is going on beyond normal biomechanical problems. Here is the UK research:
- Participants offered rich and detailed accounts of the impact and lived experience of Patellofemoral Pain Syndrome, including:
- loss of physical and functional ability;
- loss of self-identity;
- pain-related confusion and
- difficulty making sense of their pain;
- pain-related fear, including fear-avoidance and ‘damage’ beliefs;
- inappropriate coping strategies and fear of the future.
The researchers concluded: “The current consensus that best-evidence treatments consisting of hip and knee strengthening (physical therapy and exercise) may not be adequate to address the fears and beliefs identified in the current study.
Hip and knee strengthening (physical therapy and exercise) may not be adequate to heal the problem. Are they actually making it worse? Especially in women?
Doctors in the Netherlands writing in the medical journal Pain Medicine, (21) reviewed the theory that repeated stress and overloading on a knee with patellofemoral pain may sensitize nociceptors (nerve cell endings) to be even more sensitive to painful stimuli (hyperalgesia).
- Let’s sidetrack for a moment. The person with patellofemoral pain may have gotten that way because of repeated overload, as in running. He/she may have embarked on an aggressive physical therapy campaign to get themselves back to running. Their symptoms got worse. See below for how this impacts women runners.
Here is the conclusion from this research: “Local and generalized pressure hyperalgesia, suggesting alterations in both peripheral and central pain processing (you feel pain more), were present in patients with patellofemoral pain, though females with patellofemoral pain were most likely to suffer from generalized hyperalgesia.”
- In women, the pain became more generalized and pain spread beyond the knee.
Patellofemoral pain syndrome impacts the whole body
In a third 2018 study, doctors at the Erasmus University Medical Center in The Netherlands published findings that help understand patellofemoral pain syndrome impacting the whole body. Publishing in the journal Pain Medicine,(22) the Dutch team found knee and generalized (whole-body) stress and overload hyperalgesia in these patients suggesting the knee pain caused alterations in both peripheral (musculoskeletal nerves outside of the brain and spinal cord) and central pain (nerves in the central nervous system) processing.
- What this all means is that continued stress on the knee accelerated pain sensitivity. You feel more pain than the damage to the knee should be causing.
These troubling findings were expanded on in research published in May 2017 in the British Journal of Sports Medicine where the physiological component of Patellofemoral Pain Syndrome was examined:
- “Anxiety, depression, catastrophizing and fear of movement may be elevated in individuals with Patellofemoral Pain Syndrome and correlate with pain and reduced physical function.”(23)
Patellofemoral cartilage surgery?
For many people, surgery may or “will have to be recommended.” For many people, surgery will be a successful procedure and meet their expectations and hope. We typically do not see patients who had successful surgery. We see the patients who did not, have lingering complications or a general sense of instability about the knee.
For a frustrated athlete, the call of surgery is strong. Surgery, however, is usually not indicated for Patella Pain Syndrome unless the non-surgical treatment options we explored earlier in this article have been exhausted.
When we discuss surgery it is always best to bring in surgical consults from medical research.
“Unrealistic expectations are common and will lead to disappointment.”
In June 2018, research led by Harvard Medical School published in the journal Current Reviews in Musculoskeletal Medicine (26) warned surgeons and patients, especially athletes, to have a realistic expectation of what cartilage repair in the patellofemoral joint surgery can really offer them:
“Cartilage repair in the patellofemoral joint has demonstrated increasingly good outcomes in patients with patellofemoral cartilage defects after conservative treatment has failed. . . It is of utmost importance to discuss with the patient current functional limitations in sports and activities of daily living, to elucidate the patient’s goals and expectations, and to go over the rehabilitation and recovery time.
Unrealistic expectations are common and will lead to disappointment.
Careful evaluation of the knee and lower extremity, through physical examination and imaging studies, is crucial. This will allow planning a comprehensive treatment approach for the cartilage repair procedure, as well as any additional pathology that needs to be addressed in a staged or concomitant fashion.”
What is being said here is that the surgery is usually successful as far as surgery goes. But it is usually not successful in helping the patient/athlete with their goals have had the surgery. To get back to sports or work quickly. “Unrealistic expectations are common and will lead to disappointment.”
The prevalence and change in neuropathic pain or pain catastrophizing before and 12 months following patellar stabilization surgery for patellofemoral instability
A July 2021 paper in the journal International orthopaedics lead by University of Oxford (36) attempted to determine the prevalence and change in neuropathic pain or pain catastrophizing before and 12 months following patellar stabilization surgery for patellofemoral instability.
- Data from 84 patients with patellofemoral instability requiring stabilization were analyzed.
- Fifty percent (42/84) underwent Medial Patellofemoral Ligament (MPFL) reconstruction alone, and
- 16% (13/84) had both trochleoplasty (surgery that creates or deepen the groove in the trochlea to prevent recurrent patella dislocations) and MPFL reconstruction.
- At 12 months post-operatively there was a statistically significant reduction in average Pain Catastrophizing Scores but no change in average pain scores. There was a statistically significant improvement in better stability and function scores.
- The prevalence of pain catastrophizing decreased from 31% pre-operatively to 24% post-operatively, whereas the prevalence of neuropathic pain remained consisted (10-11%).
- Neuropathic pain and catastrophizing symptoms are not commonly reported and did not significantly change following patellofemoral stabilization surgery. Whilst low, for those affected, there remains a need to intervene to improve outcomes following patellofemoral instability surgery.
“This rise in surgical intervention has brought about various complications.”
In the journal Sports Medicine and Arthroscopy Review, (March 2017) (27) Dr. Nick Caplan Ph.D., wrote:
“In recent years, surgical interventions for patellofemoral joint instability have gained popularity, possibly revitalized by the recent advances in our understanding of patellofemoral joint instability and the introduction of a number of new surgical procedures. This rise in surgical intervention has brought about various complications.”
Dr. Caplan and his associates went on to describe the various complications associated with certain surgeries including:
- Patella-medial patellofemoral ligament reconstruction
- This is a surgery usually reserved for knee cap dislocation. As patella pain syndrome may have patellar maltracking is a cause, this is where the patella moves out of its groove resulting in damage to the cartilage that covers its back, it is thought that surgical replacement of the patella-medial patellofemoral ligament will provide ample stability to the knee cap and alleviate pain.
- While we agree that the patella-medial patellofemoral ligament plays a major role in providing pain-free knee movement. We do not agree that surgery is the best way to repair it unless there is a complete “disintegration” injury. In this type of injury, the ligament literally explodes and there is nothing left to repair.
- We have an extensive article on Surgery and non-surgical treatments for acute and chronic knee cap dislocation that explains this procedure further.
- Tibial tubercle osteotomy
- In this surgery, the patella tendon is moved by slicing off the bone it attaches to, moving it on the shin bone (tibia), and then reattaching the bone with the tendon to the shin bone with a screw.
- The goal of this surgery is to provide stability to the knee by using the re-positioned tendon to hold the patella in the correct position on the knee.
Younger patients have better surgical results, but what do you do with older patients? Patellofemoral arthroplasty?
In November 2019, (28) orthopedists at the State University of New York at Buffalo published a study suggesting “that patients have improved clinical outcomes after microfracture of symptomatic patellofemoral chondral lesions at midterm follow-up. Our review also found some evidence to suggest that younger patients may have improved clinical outcomes that are more durable over time compared with older patients. However, we could not draw any definitive conclusions regarding the effect of location, size, or severity of the chondral lesion.”
Older patients may not fare as well. So what do we do with them? Knee cap replacement?
Patellofemoral arthroplasty or “knee cap replacement,” is a surgery that can be performed in isolation if the patella osteoarthritis is the main cause of a patient’s pain. It is usually reserved for older patients for whom microfracture or arthroscopic patella surgery was not or is deemed to not be successful.
Botulinum toxin injections as a salvage therapy
An October 2021 study (29) from leading Israeli universities and New York University NYU Langone Orthopedic Hospital and published in the journal Knee surgery & related research examined the imbalance between the vastus medialis oblique (one of the four quadricep muscles) and the vastus lateralis (the largest of the quadriceps muscles). It is this imbalance that can lead to patella malalignment and considerable pain and reduced quality of life. This study tried to determine the effectiveness of botulinum toxin injections in patients, average age 50, treated with a botulinum toxin injection and then physical therapy. What the researchers found that in selected patients a single intervention of botulinum toxin injection to the vastus lateralis muscle combined with physiotherapy is beneficial for the treatment of patients with persistent and difficult to treat Patellofemoral Pain Syndrome.
What this study expressed is a problem of instability and imbalance because one muscle tugged harder on the patella than the other. The same can be true for ligaments.
Solving Patellofemoral Pain Syndrome is recognizing the problem of knee instability
We are going to look at the problem of Patellofemoral Pain Syndrome as a problem of knee instability. A problem that can be treated with regenerative medicine injections beyond botulinum toxin injection.
In the research above we mentioned that knee braces or sleeves could provide some temporary relief especially psychologically. Medical university researchers shared their observations on what a knee brace could do for patellofemoral pain symptoms.
Writing in the European journal Gait Posture published by Oxford University, the researchers discovered that the most beneficial aspect of wearing a brace was during walking and that the brace helped coordinate muscle activity around the knee. (30) This theory was tested among 12 women aged 20-30 years with a diagnosis of patellofemoral pain.
- What is this study suggesting the knee brace provides stability so the muscles could function correctly. Of course, knee braces are not long-term treatments for knee cap instability. Treatments that stabilize the knee by strengthening the ligaments and tendons are.
You must treat the whole knee to fix the problem of patella pain
A November 2017 study in the journal Radiology and Oncology (31) discussed what radiological findings revealed in 100 patients with patella problems.
- Mild osteoarthritis (grade I and II) was determined in 55 patients
- Severe osteoarthritis (grade III and IV) in 45 cases.
- The cartilage behind the knee cap at the retropatellar joint:
- 25 patients were assessed as normal cartilage,
- 29 patients were diagnosed with mild chondromalacia patella (grade I and II) and
- 46 with severe chondromalacia patella (grade III and IV).
- Medial meniscus tear was determined in 51 patients.
- Severe osteoarthritis and chondromalacia patella were positively correlated with a meniscal tear. (If you have chondromalacia patella you likely have a meniscus tear).
- The researchers observed a greater prevalence of bursitis in the medial compartment of the knee in patients with severe osteoarthritis and medial meniscus tear.
Comprehensive Prolotherapy for Patellofemoral Pain Syndrome – treating the whole knee
Research: “. . . patients with chondromalacia patella who received Prolotherapy reported a significant decrease in their levels of pain at rest, normal activity, and exercise, in addition to an improvement of range of motion, decrease in knee stiffness, and reduction in crepitus.”(29)
In this section, we will explain the regenerative injection treatment Prolotherapy
When we examine a patient with patellofemoral pain syndrome, we can see that the patella is usually “tracking laterally.” This means that the knee cap is slightly out of the central groove it normally sits in and has moved to one side. This is reflected on x-ray such as the one below.
We explain to the patient that our goal of treatment is to get the kneecap back into its groove with simple dextrose injections targeting the muscle attachments that connect the muscle to the knee cap (the quadriceps tendon at the patella tendon). We also explain that we want to target the various ligaments in the knee, to strengthen them, and help pull the knee back into correct anatomical alignment.
The treatment is demonstrated and explained in the video above.
In 2014, our staff at Caring Medical published research findings in a paper entitled: Outcomes of Prolotherapy in Chondromalacia Patella Patients: Improvements in Pain Level and Function in the medical journal Clinical Medicine Insights Arthritis and Musculoskeletal Disorders. (32)
In this paper, our team evaluated the effectiveness of Prolotherapy in resolving pain, stiffness, and crepitus, and improving physical activity in chondromalacia patients. We examined and treated Sixty-nine knees with Prolotherapy in 61 patients (33 female and 36 male) who were 18–82 years old (average, 47.2 years).
Following Prolotherapy treatments:
- Patients experienced statistically significant decreases in pain
- Stiffness and crepitus decreased after Prolotherapy,
- Range of Motion increased.
- Patients reported improved walking ability and exercise ability after prolotherapy.
- No side effects of prolotherapy were noted.
- Only 3 of 69 knees were still recommended for surgery after Prolotherapy.
- Prolotherapy decreased chondromalacia patella symptoms and improved physical ability.
- Patients experience long-term improvement without requiring pain medications.
Demonstration of the treatment with Ross Hauser, MD
A summary explanation and learning points of this video are presented below:
- The patient in this video has joint hypermobility syndrome. She has had many different body parts treated with Prolotherapy. We have had good success with Prolotherapy treatments providing her joint stability and pain relief. She has had her shoulders, ankles, and lower back treated.
- The patient is an avid hiker and has a new onset of pain in the knee.
The treatment begins at 1:50 of the video
- This is a comprehensive Prolotherapy treatment of the whole knee.
- The patient tolerates the treatment very well
- Treatment of the knee’s lateral side at 2:10. The LCL is addressed.
- At 2:20 Most of the time the patella tracking issues are more of a medial knee ligament laxity problem as the patella tracks laterally. So we have to tighten medial ligaments, attachments, and stabilizers.
- At 3:00 injections into the ligaments and tendon attachments that connect the patella to the femur. The patellofemoral ligaments including the medial patellofemoral ligament which provides the patella from tracking sideways when it is strong or strengthened.
- At 3:20 addressing the problem of patella tendinosis.
Recommendation to a third knee surgery: When the patella pain does not respond to conservative care treatments
In the image below we see an x-ray revealing chondromalacia patella and bone spur in a 66 year-old female patient who was seeking treatment for knee osteoarthritis pain and a grinding sensation under her kneecap. Patient had two previous knee surgeries. She was getting minimal improvement from Prolotherapy treatments, To assess her situation, an x-ray was ordered. The x-ray revealed minimal joint space under her kneecap consistent with chondromalacia patella and the grinding sensation she experienced. Notice also the hook bone spur offer patella. Because of the abnormality of the bone spur, continuing Prolotherapy was not the best treatment option for her and despite two previous surgeries, she needed an orthopedic consult.
PRP and Prolotherapy
- PRP treatment takes your blood, like going for a blood test, and re-introduces the concentrated blood platelets from your blood into areas of chronic joint and spine deterioration.
- Your blood platelets contain growth and healing factors. When concentrated through simple centrifuging, your blood plasma becomes “rich” in healing factors, thus the name Platelet RICH plasma.
- The procedure and preparation of therapeutic doses of growth factors consist of an autologous blood collection (blood from the patient), plasma separation (blood is centrifuged), and application of the plasma rich in growth factors (injecting the plasma into the area.) In our office, patients are generally seen every 4-6 weeks. Typically three to six visits are necessary per area.
PRP as we perform it is NOT a single injection. It is a comprehensive treatment that addresses problems, weakness, and instability of the whole knee capsule.
- We typically treat the anterior and posterior of the knee (the front and back)
- Some injection areas included in the treatments are at the lateral condyle of the tibia to get to one of the attachments of the anterior cruciate ligament.
- Knee instability is a common condition that causes chronic knee pain so when a person is getting treated for knee instability you have to make sure that the various ligaments that are causing the instability are being treated.
- Other attachments of the anterior cruciate ligament are treated.
- Platelet-rich plasma is very effective at helping resolve any issues that relate to knee instability especially of the cruciate ligament specifically the anterior cruciate ligament as well as meniscal tears and degenerated meniscus.
- This particular person has knee instability from primarily the anterior cruciate ligament being lax or injured. That injury will also cause instability to occur in the medial-lateral collateral ligament. This is why we treat the lateral knee and the medial knee and the attachments of the medial collateral ligament.
Continuing research 2018, The Use of Prolotherapy for Chondromalacia Patella (Patellofemoral Pain Syndrome)
In 2018, our research team published new findings in the Journal of Prolotherapy. (33) Here we found:
- In summary, the outcomes of this study illustrated that Prolotherapy may be an effective treatment for reducing the symptoms of chondromalacia patella.
- The observed decreases in symptoms of patients who received Prolotherapy were shown to be highly significant.
- The patients in this study who received Prolotherapy improved in the overall level of pain, function, and mobility in the case of chondromalacia patella.
- These improvements were seen in varying durations of initial pain and treatment and gender.
- Improvements observed with Prolotherapy were seen in patients of all ages, making the potential benefits of Prolotherapy generalizable to the majority of the U.S. adult population.
Bone Marrow Aspirate or Bone Marrow Stem Cell Therapy.
Stem cell therapy can be an effective treatment for some patients, it can also easily fail as a treatment in some patients. We have two extensive articles on our website that can explain who stem cell therapy can and cannot help and why the treatment may fail. Please see When stem cell therapy works and does not work for your knee pain and Does stem cell therapy for knee meniscus tears and post-meniscectomy work?
An example of why or why not the treatment did not work is typically seen in emails we get.
I was diagnosed with patella femoral pain syndrome and chondromalacia and was recommended by an orthopedic to get Stem Cell injections (from bone marrow). After the injections, my condition worsen. I now have lateral tilting and subluxation of both patellas. Before I only had pain during weight-bearing activities and now I have chronic discomfort when sitting, standing, and sleeping. Several orthopedists have now recommended hyaluronic acid injections but I am not hesitant to inject anything else into my knees.
In this situation did the stem cells make the pain worse or did the ineffectiveness of the treatment prevent the continued deterioration of the knee joints. In many cases stem cell therapy is tried, it is given as a single cortisone-like injection with the promise that the stem cells injected will rebuild the knee and the patient and doctor wait for the results. While they are waiting, the knee continues to worsen because the treatment was not sufficient to treat the problem.
We have seen good success in selecting patients with knee problems using bone marrow-derived stem cell therapy. We say select because we do not find it necessary to offer this treatment to every patient.
A July 2021 study in the journal Stem Cell Research & Therapy (34) offers support for the use of stem cell therapy for chondromalacia patella and pain in the patellofemoral joint.
“(Various treatments) are conventionally proposed to treat cartilage lesions in the patellofemoral joint, but none have emerged as a gold standard, neither to alleviate symptoms and function nor to prevent osteoarthritis degeneration. Recently, researchers have been focused on cartilage-targeted therapy. Various efforts including cell therapy and tissue emerge for cartilage regeneration exhibit as the promising regime, especially in the application of mesenchymal stem cells (MSCs). Intra-articular injections of variously sourced MSC are found safe and beneficial for treating chondromalacia patella with improved clinical parameters, less invasiveness, symptomatic relief, and reduced inflammation. The mechanism of MSC injection remains further clinical investigation and is tremendously promising for chondromalacia patella treatment.”
Can we help you?
If this article has helped you understand treatment options for Patellofemoral Pain Syndrome and chondromalacia patella and you would like more information, you can get help and information from our specialists
1 Collado H, Fredericson M. Patellofemoral pain syndrome. Clinics in sports medicine. 2010 Jul 1;29(3):379-98. [Google Scholar]
2 Halabchi F, Abolhasani M, Mirshahi M, Alizadeh Z. Patellofemoral pain in athletes: clinical perspectives. Open access journal of sports medicine. 2017;8:189. [Google Scholar]
3 Sigmund KJ, Hoeger Bement MK, Earl-Boehm JE. Exploring the pain in patellofemoral pain: A systematic review and meta-analysis examining signs of central sensitization. Journal of Athletic Training. 2020 Nov 25. [Google Scholar]
4 Liang JN, Budge S, Madriaga A, Meske K, Nguyenton D, Ho KY. Neurophysiological changes of brain and spinal cord in individuals with patellofemoral pain: a systematic review and meta-analysis protocol. BMJ Open. 2021;11(7):e049882. Published 2021 Jul 26. doi:10.1136/bmjopen-2021-049882
5 Greaves H, Comfort P, Liu A, Herrington L, Jones R. How effective is an evidence-based exercise intervention in individuals with patellofemoral pain?. Physical Therapy in Sport. 2021 Jul 13. [Google Scholar]
6 Fatimah I, Waqqar S. Effects of tibiofemoral mobilization in patients of Patellofemoral pain syndrome. JPMA. The Journal of the Pakistan Medical Association. 2021 Nov 1;71(11):2506-10.
7 Andreucci A, Roos EM, Rasmussen S, Olesen JL, Hölmich P, Thorborg K, Rathleff MS. Analgesic use in adolescents with patellofemoral pain or Osgood–Schlatter Disease: a secondary cross-sectional analysis of 323 subjects. Scandinavian Journal of Pain. 2021 Dec 3. [Google Scholar]
8 Young JL, Snodgrass SJ, Cleland JA, Rhon DI. The relationship between knee radiographs and the timing of physical therapy in individuals with patellofemoral pain. PM&R. [Google Scholar]
9 Aysin IK, Askin A, Mete BD, Guvendi E, Aysin M, Kocyigit H. Investigation of the Relationship between Anterior Knee Pain and Chondromalacia Patellae and Patellofemoral Malalignment. The Eurasian journal of medicine. 2018 Feb;50(1):28. [Google Scholar]
10 Ferreira AS, de Oliveira Silva D, Del Priore LB, Garcia CL, Ducatti MH, Botta AF, Waiteman MC, de Azevedo FM. Differences in pain and function between adolescent athletes and physically active non-athletes with patellofemoral pain. Physical Therapy in Sport. 2018 Sep 1;33:70-5. [Google Scholar]
11 Uboldi FM, Ferrua P, Tradati D, Zedde P, Richards J, Manunta A, Berruto M. Use of an Elastomeric Knee Brace in Patellofemoral Pain Syndrome: Short-Term Results. Joints. 2018 Jun 22. [Google Scholar]
12 Lack S, Barton C, Vicenzino B, Morrissey D. Outcome predictors for conservative patellofemoral pain management: a systematic review and meta-analysis. Sports Medicine. 2014 Dec 1;44(12):1703-16. [Google Scholar]
13 Priore LB, Lack S, Garcia C, Azevedo FM, de Oliveira Silva D. Two weeks of wearing a knee brace compared to minimal intervention on kinesiophobia at 2 and 6-weeks in people with patellofemoral pain: A randomized controlled trial. Archives of Physical Medicine and Rehabilitation. 2019 Dec 10. [Google Scholar]
14 Xiao H, Li Z, Lei S. Gait retraining for runners with patellofemoral pain: A protocol for systematic review and meta-analysis. Medicine. 2021 May 14;100(19). [Google Scholar]
15 Bramah C, Preece SJ, Gill N, Herrington L. A 10% increase in step rate improves running kinematics and clinical outcomes in runners with patellofemoral pain at 4 weeks and 3 months. The American journal of sports medicine. 2019 Dec;47(14):3406-13. [Google Scholar]
16 Lack S, Neal B, Silva DD, Barton C. How to manage patellofemoral pain–Understanding the multifactorial nature and treatment options. Physical Therapy in Sport. 2018 Jul 1;32:155-66. [Google Scholar]
17 Rathleff MS, Rasmussen S, Olesen JL. Unsatisfactory long-term prognosis of conservative treatment of patellofemoral pain syndrome. Ugeskrift for laeger. 2012 Apr;174(15):1008-13. [Google Scholar]
18 Mattila VM, Weckström M, Leppänen V, Kiuru M, Pihlajamäki H. Sensitivity of MRI for articular cartilage lesions of the patellae. Scandinavian Journal of Surgery. 2012 Mar;101(1):56-61. [Google Scholar]
19 McConnell J. Management of a difficult knee problem. Man Ther. 2012 Jun 27. [Google Scholar]
20 Smith BE, Moffatt F, Hendrick P, Bateman M, Rathleff MS, Selfe J, Smith TO, Logan P. The experience of living with patellofemoral pain—loss, confusion and fear-avoidance: a UK qualitative study. BMJ open. 2018 Jan 1;8(1):e018624. [Google Scholar]
21 van der Heijden RA, Rijndertse MM, Bierma-Zeinstra SM, van Middelkoop M. Lower Pressure Pain Thresholds in Patellofemoral Pain Patients, Especially in Female Patients: A Cross-Sectional Case-Control Study. Pain Medicine. 2017 Apr 6;19(1):184-92. [Google Scholar]
22 van der Heijden RA, Rijndertse MM, Bierma-Zeinstra SM, van Middelkoop M. Lower Pressure Pain Thresholds in Patellofemoral Pain Patients, Especially in Female Patients: A Cross-Sectional Case-Control Study. Pain Med. Epub 2017 Apr 6 Jan 2018 [Google Scholar]
23 Maclachlan LR, Collins NJ, Matthews MLG, Hodges PW, Vicenzino B. The psychological features of patellofemoral pain: a systematic review. Br J Sports Med. 2017 May;51(9):732-742. [Google Scholar]
24 Pazzinatto MF, de Oliveira Silva D, Pradela J, Coura MB, Barton C, de Azevedo FM. Local and widespread hyperalgesia in female runners with patellofemoral pain are influenced by running volume. J Sci Med Sport. 2017 Apr;20(4):362-367. [Google Scholar]
25 Noehren B, Shuping L, Jones A, Akers DA, Bush HM, Sluka KA. Somatosensory and Biomechanical Abnormalities in Females With Patellofemoral Pain. Clin J Pain. 2016 Oct;32(10):915-9. [Google Scholar]
26 Mestriner AB, Ackermann J, Gomoll AH. Patellofemoral Cartilage Repair. Current reviews in musculoskeletal medicine. 2018 Jun 1;11(2):188-200. [Google Scholar]
27 Caplan N, Nassar I, Anand B, Kader DF. Why do patellofemoral stabilization procedures fail? Keys to success. Sports medicine and arthroscopy review. 2017 Mar 1;25(1):e1-7. [Google Scholar]
28 Van der List JP, Chawla H, Zuiderbaan HA, Pearle AD. Survivorship and functional outcomes of patellofemoral arthroplasty: a systematic review. Knee Surgery, Sports Traumatology, Arthroscopy. 2017 Aug 1;25(8):2622-31. [Google Scholar]
29 Kesary Y, Singh V, Frenkel-Rutenberg T, Greenberg A, Dekel S, Schwarzkopf R, Snir N. Botulinum toxin injections as salvage therapy is beneficial for management of patellofemoral pain syndrome. Knee Surgery & Related Research. 2021 Dec;33(1):1-8.
30 Sker FS, Anbarian M, Yazdani AH, Hesari P, Babaei-Ghazani A. Patellar bracing affects sEMG activity of leg and thigh muscles during stance phase in patellofemoral pain syndrome. Gait & Posture. 2017 Jun 29. [Google Scholar]
31 Resorlu M, Doner D, Karatag O, Toprak CA. The relationship between chondromalacia patella, medial meniscal tear and medial periarticular bursitis in patients with osteoarthritis. Radiology and oncology. 2017 Nov 29;51(4):401-6. [Google Scholar]
32 Hauser RA. Outcomes of Prolotherapy in Chondromalacia Patella Patients: Improvements in Pain Level and Function. Clin Med Insights Arthritis Musculoskelet Disord. 2014; 7: 13–20. [Google Scholar]
33 Maddela HS, Hauser RA. The Use of Prolotherapy for Chondromalacia Patella (Patellofemoral Pain Syndrome). Journal of Prolotherapy. 2018;10:e1000-e1008.
34 Zheng W, Li H, Hu K, Li L, Bei M. Chondromalacia patellae: current options and emerging cell therapies. Stem Cell Research & Therapy. 2021 Dec;12(1):1-1. [Google Scholar]
35 Curran AJ, Neal BS, Barber P, Bartholomew C, Morrissey D, Lack SD. Clinicians’ experience of the diagnosis and management of patellofemoral pain: A qualitative exploration. Musculoskeletal Science and Practice. 2022 Apr 1;58:102530. [Google Scholar]
36 Smith TO, Choudhury A, Fletcher J, Choudhury Z, Mansfield M, Tennent D, Hing CB. Changes in pain catastrophization and neuropathic pain following operative stabilisation for patellofemoral instability: a prospective study with twelve month follow-up. International Orthopaedics. 2021 Jul;45(7):1745-50. [Google Scholar]
37 Foss KD, Slutsky-Ganesh AB, Diekfuss JA, Grooms DR, Simon JE, Schneider DK, Jayanthi N, Lamplot JD, Hill D, Pombo M, Wong P. Brain Activity During Experimental Knee Pain and Its Relationship With Kinesiophobia in Patients With Patellofemoral Pain: A Preliminary Functional Magnetic Resonance Imaging Investigation. Journal of Sport Rehabilitation. 2022 Mar 12;1(aop):1-0. [Google Scholar]
This article was updated March 28, 2022