Lars Blønd

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Patellofemoral Osteoarthritis

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Patellofemoral osteoarthritis is arthritis in the joint between the kneecap and the groove for the kneecap. Sometimes isolated arthritis leads to anterior knee pain. One typical problem is pain during stairclimbing. There are several treatments option for this problem.
Patellofemoral osteoarthritis

If you are troubled by anterior knee pain due to patellofemoral osteoarthritis, you should generally try out non operative treatment before you consider surgery. What is happening is the cartilage in either (or both) on the back site of the kneecap or in groove for the kneecap has weared away to some degree.

Surgery patellofemoral osteoarthritis

The exist many different types of surgery for patellofemoral osteoarthrisis. The right choice of surgery dependens on several factors. Below you can read about some of the surgical possibilities.

Arthroscopic debridement - meaning smoothening by pinhole surgery.

Sometimes an arthroscopy, with smoothening of uneven cartilage and with removal of inflammed synovial tissue, can reduce the catching sensation and reduce pain. However this procedure can´t bring in a new layer of cartilage. Sometimes there is malalignment, meaning the the tracking of the patella into the trochlea is crooked. If this is the case, this eventually need to be fixed concomitantly.


Lateral facetectomy. Means to take away a piece of the outer part of the kneecap. 

Often is the osteoarthritis localised almost on the outsite of the patella. By removing the weared outer part of the patella, the pain can be resolved. This can be done either by open or arthroscopic surgery. On the picture on the right you see such and example. The left picture is before suregery.

Fulkerson osteotomy

By this special surgery, the tibial tubercle (the point of attachment of the patellar tendon) is moved more to the inner site and to the front. This surgery is planned if the patellofemoral joint has nice cartilage on the inner half of the joint and the tibial tubercle is outwards placed. This can be seen on an axial MRI. Often the surgery is combined with a lengthening of the lateral retinaculum.

Patellofemoral Arthroplasty

If you have significant osteoarthritis  between the kneecap a Hemicap Wave prosthesis can be a good option. Just to avoid confusion Patellofemoral arthroplasty, prosthesis or replacement are the same.

In stead of doing a total knee prosthesis this smaller surgery can work out great. Actually the results are better with this lesser surgery, than for a total knee replacement, if you have isolated patellofemoral osteoarthritis. Especially if you osteoarthritis is due to trochlear dysplasia. You can say that the Hemicap Wave is a metal deepening trochleoplasty (a deepening of the groove surgery).

If the kneecap is unstable it can be stabilized by a concomitant MPFL reconstruction using an artificial ligament (FiberTape).

After treatment Patellofemoral prosthesis

After a surgery you are allowed fully weightbearing and free range of movement. You will leave hospital the same day. 

Physiotherapy normally starts after 2 weeks. Car driving can normally be optained after 3-4 weeks. The knee will often be weakened by swolling and pain for several month. You can expect the knee to be better than preoperatively after 3 month.

How long does a Patellofemoral prosthesis last?

Normally about 75% of patient will not have been given neither a patellofemoral replacement or at total knee replacement within 15 Years. Those data are related to so called onlay prosthesis, hopefully inlay prosthesis like the Hemicap Wave will last even longer

This i a knee model demonstrating a Hemicap Wave prosthesis


Patellofemoral prosthesis
Patellofemoral protese

Hemicap Wave patellofemoral protese

At left you see an axial MRI view of a 36 year old women. It demonstrate severe trochlear dysplasia and patellofemoral osteoarthritis. She had severe anterior knee pain for 20 years, before she had a Hemicap Wave. It´s likely that she could have had 20 year with less pain, and perhaps also postponed the time for a PF arthroplasty, if she had undergone a trochleoplasty back in time.


X-Ray demonstrating a Hemicap Wave Patellofemoral prothesis

Squinting Patella – Rotational osteotomies

Squinting Patella - Rotational osteotomies in either your femur (DFO) and/or your tibia (HTO) can be necessary to obtain a good outcome. All of us have variations in the way we are build, however some persons are build rather extreme. If either your femur or you tibia are rotated too much in either directions, this can cause kneecap problems. 
Femoral (DFO) or tibia rotational osteotomies

Are your hip or thigh bone (femur) turned or rotated too much inwards or outwards? If you kneecaps are pointed towards each other you call this squinting patella. For some people this can lead to anterior knee pain (patellofemoral pain) and/or patella instabiity. By clinical examination this can be ruled out like seen below. However clinical examination is difficult. More precisely this torsional abnormalies can be measured by either CT or MRI of femoral neck + knee + ankle. If your rotation is abnormal and you have significantly problems you can be helped out by derotational osteotomies. Sometimes only the femur (Derotational Femoral Osteotomy = DFO) or only the tibia (High Tibia Osteotomy = HTO) needs to be rotated. Eventually both have to rotated simultaneously.

This girl was severely troubled by anterior knee pain for several years and if she turn her feet in frontal direction she have squinting patella. Physiotherapy guided exercises for hip and knee did not work out. She also tried shoes inlay.

Anteversion of hip

This is a typical example of a young women having had anterior knee pain for several years. Notice how much she can rotate in her hips. In one direction it´s too much, while in the other direction it´s too little. This is due to increases femoral anteversion.

On the picture left you can notice that she her knee caps point inwards. On the picture on the right you can notice that her left knee is not that extreme anymore. Her femur and tibia both were rotated 10 degrees. She previously suffered for chronic anterior knee pain. In a case like this you call it 'miserable malaligment' or better 'tetratorsional malalignment'. Since she was desperate, she had visited several doctors, orthopaedic surgeons as well as several physiotherapist. She was tolded that everything was normal. She had several times been told that she was a hypochondriac and she should consult a psychologist.
Picture at left is a CT scan 3D reconstruction. Try to notice the rotation of the left femur. It is rotated too much. The patient have had recurrent patella dislocation. She had previously undergone MPFL reconstruction, however this failed after a couple of years. She had a derotational femoral osteotomy and a revision MPFL reconstruction and responed positively. However she as most others had to have the plate removed when the osteotomy had healed securely. You can see the x-ray on the right, before the plate was removed.

The typical patients with this problem often have a long history, seeing many physiotherapist, doctors and orthopedic surgeons, and have been told nothing is wrong or have undergone failed surgery . Often when the surgery and recovery (often with plate removal as a second surgery) the patients ask me why their problem was not noticed before hand and regret the many years wasted. I naturally understand why they are upset.

This young women above had patellofemoral pain since she was 12 years old and was succesfully operated

This 30 year young man became pain free and active, however he was really sad for the years he felt he had missed

Importantly many patients are told that their tibial tubercle is located to much to the outer site (lateral) and therefore they are offered at medialization of the tibial tubercle. Nevertheless is the problem are commonly a result of an external rotation of the tibia and a rotational osteotomi gives better outcome. So if you is told you have and increased TT-TG distance be aware of this.

Patellofemoral Pain and Trochlear Dysplasia

Patellofemoral knee pain and Trochlear Dysplasia are related and you can read more below.
Patellofemoral knee pain - also called anterior knee pain, is a symptom 

First of all is patellofemoral knee pain a symptom and not a disease. Trochlear Dysplasia means a shallow or flat groove for the kneecap. You might have an MRI that says trochlear dysplasia or dysplastic trochlea, which is the same. It is likely you have no symptoms from this. Nevertheless are a few patients troubled by severe chronic patellofemoral pain and trochlear dysplasia. Trochlear dysplasia increases the cartilage forces in the knee joint. What happens is that the cartilage contact area is too little. This gives high pressure on a little area. Some of these patient might be helped very well by a trochleoplasty surgery since the cartilage is unloaded. Read more on the page for anterior knee pain, the page for trochleoplasty and the page for trochlear dysplasia. It´s important to say that all types of Trochlear Dysplasia predispose to anterior knee pain and that there are several other factors that is involved in patellofemoral pain

Second opinion

Eventually get a second opinion from another patellofemoral surgeon - not just a standard orthopaedic surgeon. You are also welcome to book an online consultation with me for 175 euro prepaid. I need to see you MRI before the meeting. (contact me on [email protected]). Another solution is to accept the pain and reduce your level of activity to a lower level. The knee surgeon, Scott Dye, has for years spoken for the 'functional envelope'. This could be a solution for you. Eventually you can do some reading in the following special issue incl a paper from my hand.

Scientific evidence is slowly increasing

First I published a case report on arthroscopic trochleoplasty for chronic patellofemoral pain and trochlear dysplasia - link here. A new publication confirms that patients having chronic patellofemoral pain and trochlear dysplasia may benefit from a trochleoplasty - link here. 

An example

Left you see a axial view of a 36 year old women. She had severe anterior knee pain for 20 years. During her patellofemoral arthroplasty surgery there were no cartilage left in the patellofemoral joint. If she just have had a trochleoplasty when she was younger, this may have given her 20 years without pain and likely this soulc also have prevented the development of osteoarthritis

Chronic patellofemoral pain

Back in 1998 we did a follow-up on patients having anterior knee pain.We found, that about half of the patients continue to have light to moderate pain for years. About one out of 10 continues to have severe chronic pain. You can download a PDF copy here. Later have these findings been confirmed by several others. 

Is there a relationship between patellofemoral pain and patellofemoral arthritis?

The clinical entity called anterior knee pain (AKP) or patellofemoral pain (PFP) or chondromalacia patellae can leads to arthritis. This relationship has lately been revealed. It seems logic that some severely troubled patients ends up having arthritis. See the study from Conchie et al. 

http://www.ncbi.nlm.nih.gov/pubmed/27180253

Reference

Is there a relationship between anterior knee pain and femoral trochlear dysplasia? Assessment of lateral trochlear inclination by magnetic resonance imaging. Click here

Plica in knee

Plica Syndrome in knee

What is a Plica Syndrome or Plica Synovialis?

There are 5 types of plicae in the knee. The two most well-known plicae are the mediopatellar (medial) plica  placed on the inner site of the kneecap and the other one is the infrapatellar plica (ligamentum mucosum) placed in the front of the knee. All the five plicae have no known functions, but they are residuals from the fetal life.

What is the problem with Plicae? 

An impact on your knee or a wrong use, can cause your plica to get inflamed and then it gets swollen. The medial plica are known to catch between the kneecap and the femoral condyle and this typically causes symptoms of inner site pain and catching. The Infrapatellar plica is attached to the Hoffa Fad and moves significantly when your knee straightens and bends. Sometimes scar tissue in the infrapatellar plica can cause anterior knee pain based upon scar tissue in the plica makes it shorten up.

What is the treatment for Plicae problems?

First of all the treatment focus rest and anti-inflammatory medicine (NSAID or steroids). When your plica has restored it self, a physiotherapist can help by restoring balance and correct movement patterns to prevent recurrence. Sometimes those treatments are not sufficient and your plicae may have to be taken care of by arthroscopic surgery. Here it is very easy to remove. Some call the Infrapatellar plica problems arthrofibrosis and call the procedure arthroscopic removal of the plica - anterior interval release. Personally I do not think this is arthrofibrosis, which is a much more serious condition giving you a stiff knee.  


The other Plicae

The three other plicae are the Suprapatellare plica that occasionally can give rise to pain above the patella in the Quadriceps tendon. The Laterale plica, that can cause outer site pain. And finally there is a plica that is localized in the rear of the knee and act as valve in front of a Baker cyst.

Lars Blønd

There are 5 types of plicae in the knee

Link to a studie about the infrapatellare plica

Link to a video about the infrapatellare plice