All posts by Lars Blønd

MPFL reconstruction

MPFL reconstruction is a reconstruction of the Medial Patellofemoral Ligament

What is an MPFL reconstruction?

By MPFL reconstruction surgery your injured inner ligament for the kneecap (MPFL) is replaced by a stronger ligament that keeps the patella (kneecap) in place. The ligament goes from the inner site of the patella and the quadriceps tendon towards the medial femoral condyle. The ligament is typically harvested from the back site of the thigh, by an incision over the inner site of the tibia.

Many surgeons say that you will just need an MPFL reconstruction and there is no reason do for example a trochleoplasty.

It can be right that MPFL reconstructions are very good in most situations. Nevertheless is the MPFL reconstruction just a new ligament and just like a shoelace, there is risk that it will not last more than a few years. This can be the case if there is trochlear dysplasia etc.

Is MPFL reconstructions always a good solution?

Unfortunately I see a number of patients who had MPFL reconstruction that re-rupture. I also see a number of patients who just have pain at the inner site of the knee, based on too strong forces on the ligament. Therefore make sure that you have an MRI scan and that your surgeon knows how to look for trochlear dysplasia and patella alta and increased TT-TG distance. Eventually read more here

New data indicate that the long term results are not as good as we had hoped. Check here 

This demonstrates how the new MPFL ligament looks like from the side.

Left is an example that demonstrates how an MPFL reconstruction can be performed - the picture shows how it looks just before inserting the screw that is going to secure the ligament until it has grown tight to the bone after a few months.

After the operation?

What are you allowed to do and what can you do after an MPFL reconstruction? Normally do I never prescript braces after an MPFL reconstruction. You are allowed full weight bearing and free range of movement. Already a few days after the surgery I recommend that you start to do physiotherapy guided exercises in order to regain strength and ability to bend your knee

Sick Leave after MPFL reconstruction?

For how are you going to stay away from school or work? This is a very good question, since there is huge individual variation. Some will be already back after a week, while for those have heavy physical work it may take 2-3 month. Another thing of importance is how you transport yourself from home to school or work 

Sport

When are you allowed to return to sport? This depends on what type of sport you participate. If  it is contact sport you have to wait until the muscles are finally back in force and balance, however you always need to wait at least 4 month..​


What safety level of activity is recommended after MPFL reconstruction?Normally I do not use any brace or limitation in range of movement and I allow full weight bearing. A few days after surgery physiotherapy-guided exercises are recommended.

Shoulder Compendium

While learning about shoulder evaluation, I felt a need to make sense of all the many tests - and this 'Compendium' is the result of my efforts.

One hundred and sixty-five shoulder tests!

LARS BLØND SHOULDER COMPENDIUM


Again, apologies that this is still only available in Danish. I will get around to translating them one of these days...

Trochleoplasty – The arthroscopic version

This page is about the Trochleoplasty operation. This surgery deepen the groove in which the kneecap glides. Noteworthy the surgery can be done by arthroscopic technique. 

Background

Trochleoplasty is a surgery for the Trochlear groove, a groove that helps the kneecap (the Patella) to stay in place. By this surgery a new and a deeper groove is created to normalize your anatomy. 

Why am I going to have a groove operation?

If you are troubled by unstable kneecap or chronic anterior knee pain, you might also have an abnormal groove. This means that the groove for your kneecap is more shallow than normal or it can be even flat or convex. In short, when your knee groove is too shallow, this tends to make you kneecap unstable. It basically means that it might either go half the way out (called subluxation) or it even dislocate. The condition of having a shallow groove is called trochlear dysplasia (abnormal groove). In these cases were you groove is flat, this special operation might be the best option for you.

If you have a shallow groove

We know when your groove is shallow or flat, it is a result of too much bone in the center of the groove. This basically means that you have too little bony support for the kneecap. 

The Surgery 

The principle of the groove surgery is basically to deepen the groove. First is the cartilage released from the groove. Subsequently excessive bone is removed. This is followed by creation of an outer bony wall to support the patella. After that, when the groove has been deepened and re-shaped, the cartilage is re-located by means of a special blue or white bands. Those tapes or bands are later resolved. You can find picture examples by the images below. Certainly the groove operation is, from a mechanical point of view, the most anatomically correct operation to perform, if you have an abnormal groove.

History

After having invented the technique, I started out 11 years ago doing arthroscopic deepening trochleoplasty procedures. I used to do the groove procedure openly by the Bereiter method. I have stopped to do the open surgery. since it leaves a bigger scar, and in addition it is more painful and I believe that I can obtain better results by doing it arthroscopic in most situations.  

More about the groove surgery

By using the pinhole technique (arthroscopic), consequently the surgery becomes less traumatic for your knee , and therefore the rehabilitation is likely to become accelerated. To notice is the groove operation mostly done in combination with a reconstruction of the inner ligament for the kneecap (MPFL reconstruction).

Why go for arthroscopic trochleoplasty instead of open trochleoplasty?

By using the pinhole technique (arthroscopic), consequently the surgery becomes less traumatic for your knee , and I have had no case of excessive scar tissue (arthrofibrosis). Doing open trochleoplasty it´s a well known risk - read more here 

Why also MPFL reconstruction?

Why is the groove surgery not enough? And why should you also have reconstructed the MFPL? (mediale patellofemoral ligament = inner ligament for kneecap). That is first of all because the MPFL is always torn when the kneecap dislocate. It does not heal normally and therefore it has to be reconstructed. Moreover it also so, that the trochlear groove, do not provide stability to your kneecap, before the kneecap reach the trochlea. Importantly this first happens after your knee is bend about 20 degrees. This means that the MPFL is needed to provides stability to your kneecap from full straightened knee and until your kneecap reach the new groove at 20 degrees of bending. Read more about MPFL reconstruction here

Arthroscopic trochleoplasty and no MPFL reconstruction. 

If you problem is chronic anterior knee pain as a consequence of a too shallow groove, and your kneecap is stable, likewise you do not need to have the ligament to stabilize the kneecap reconstructed - eventually read more in the page about anterior knee pain.

I am Lars Blond pioneer on the arthroscopic trochleoplasty. Eventually go to the front page or read my CV or download scientific papers

Trochleoplasty by pinholes = Arthroscopic Trochleoplasty

Patients have been coming from abroad to undergo the surgery. In addition I travel to where you live.

Until now I have operated patients from 12 different countries:

Skype

In case you would like a second opinion regarding your MRI or just your general knee situation, I do Skype consultations. The cost is 150 euro - email [email protected]

Facebook

You can eventually go to Facebook. Check out either "Lars Blond + Trochleoplasty" or just "Trochleoplasty". Here you can notice more details and recent updates

The company Arthrex that help me develop the technique have now also produced at video in 4K quality - see it here

Video

Eventually read what some patients says in the testimonial page - or see this Youtube video called trochleoplasty gathering (Danish language but English text)

KneeGuru

What does KneeGuru say about arthroscopic trochleoplasty? - Read here

Frequently asked questions:
  • The surgery typically last 1½- 2½ hours.
  • When can you fly back? This depends on the distance but this is from 3 - 10 days. A seat with the possibility to straighten the leg is needed.
  • Crutches are used for 2-4 weeks - with huge individual differences
  • No brace is needed after this type of surgery and full weight bearing is allowed
  • Some think - should I start with one type of minor surgery and if I do not work, then try another surgery - I my view only one surgery should be necessary if the right one is done from the start.
  • Only one knee is operated (in one out of three both knees are involved)
  • How long is the recovery?
    The knee will improve the first one or two years

More freguently asked questions:
  • When can I return to sport or job - this has very huge individual differences and if you have an sedentary job it is about 4 weeks and lighter sports is after approx. 3 month
  • Will my insurance pay? Normally they will pay for the surgery and travelling expences (still cheaper than similar surgery in US)
  • The price for a Skype consultation incl evaluation of MRI? 150 Euro.
    MRI scans can be posted by mail, by Dropbox or webtransfer or similar (E-mail: [email protected])
  • The price for combined arthroscopic trochleoplasty and MPFL reconstruction is approx. 11000 euro incl implants (implant cost alone is 2000 euro)
  • For physiotherapy and exercises Physiotherapist Dorte Nielsen (Proalign.dk) has a huge experience of training patients troubled by patellar instability, and has seen several patients after arthroscopic trochleoplasty. Dorte Nielsen has uploaded videos on YouTube.
About Aleris-Hamlet Parken

Aleris-Hamlet Parken has very high safety. A rate of infection close to zero and with high cleanliness and has undergone accreditation after the highest international standards and use the latest technologies. All doctors are experienced doctors. All personnel speaks English.

Rehabilitation protocol after Arthroscopic Trochleoplasty and MPFL reconstruction - by Dorte Nielsen

Rehabilitation trochleoplasty
Example of an "Arthroscopic Deepening Trochleoplasty".

Before (left) and after (right). The blue band dissolves after 6 weeks and is therefore only temporary until the cartilage has healed.

MRI before (left) and after (right)
Trochlea before and and after the groove surgery 

- "It is difficult to balance a tennis ball on a football"

Second look

Two different examples of how it looks in-site the knee 3 months after a groove surgery. If you notice has the cartilage healed very nicely and blue bands/tapes are dissolved.

Second look - 3 years after

Illustration showing the tapes in place after arthroscopic trochleoplasty

Nice small scars after combined arthroscopic trochleoplasty and MFPL reconstruction

The scars after Arthroscopic Trochleoplasty and reconstruction of the medial patellofemoral ligament eight weeks postoperatively

Eight weeks after the surgery and the scars will become much more nice over time. I recommend you to use tape in the first month after surgery, since this will reduce traction in the scars. Hence you can avoid that the scars becomes wide.

Video arthroscopic trochleoplasty

Kenneth doing well one year after

Why should I also have a groove surgery and not just MPFL reconstruction?

That is a good question and some surgeon argue that it is not necessary. Maybe it is not 100% necessary if you just want stability, but if you also want a knee without anterior knee pain, trochleoplasty have to be done. Also, sometimes I see patients having trochlear dysplasia and who have had an MPFL reconstruction only. Then after some years the kneecap starts to becomes loose again because the MPFL reconstruction get loose by time. Therefore if you visit a surgeons, who do not do trochleoplasty surgery, and you do have this flatt groove. Most importantly try to get a second opinion in case this surgeon tells you that the surgery is rare, dangerous and complicated surgery since this is not correct. 

Case Study - Mikkel

Mikkel was the first patient who was operated upon with an Arthroscopic Trochleoplasty, and this was back in March 2008. Previously he had unsuccessful kneecap-stabilizing surgery and by doctor and physiotherapist he was told that he would never be able to sports again. Most noteworthy Mikkel had been troubled in both his knee since he was 8 years old and had never been able to run. Finally he underwent surgery on both his knees with the groove surgery at 29 years old. Meaning 21 years without running. 

Follow-up on Mikkel

Today is Mikkel doing well in his knees and he is running and playing soccer. He claims that the only annoyance is the sound from the knees, when he climbs stairs. Go to YouTube and listen to his and other stories during the trochleoplasty gathering in 2014. Many thanks to Asker Blønd - my son - who created this video. Click here trochleoplasty gathering.or check this video

Outcome after trochleoplasty

Generally the outcomes after groove surgery is very good, with less than 2 percent new dislocations. Consequently is the quality of life dramatically better. I have followed all my arthroscopic trochleoplasty patients for now more than 10 years and in average there as been improvements in all measured parameters and high satisfaction.  Both the technique and the results of this operation, have been published in peer reviewed journals. Today I have presented "The Arthroscopic Deepening Trochleoplasty" technique in the United States, Japan, Netherlands, UK, Sweden, Norway, Poland, Germany, Austria, Portugal and China. Moreover has the surgery been adopted by other surgeons and is now performed in ten differnet countries world wide.

Tibial Tubercle Transfer =TT?

What about having a TT osteotomy instead of a groove surgery? The fact is that no surgeon know what exactly what is best since the science has not yet given a final answer to that question. However is there many indications that the groove surgery gives better results. In addition we know that trochleoplasty surgery normalize the anatomy. Moreover does we know that patients, who have had TT surgery after a decade are having declining results. The first trochleoplasty patients I operated more than 13 years ago are still doing fine. So based on this and my clinical experience by doing both many tibial tubercle osteotomies an trochleoplasty surgeries, I prefer to do trochleoplasty if you are having severe trochlear dysplasia.

Here is the latest paper on arthroscopic deepening trochleoplasty here or simply go the page where you can find all my scientific papers

Comments on LinkedIn 2018 and more than 5000 views

Photo library with some examples of arthrocopic trochleoplasty
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Trochlear Dysplasia

Trochlear Dysplasia means that the groove (trochlea) for the kneecap (patella) is too flat or even dome-shaped. This knee condition is the single most important factor for having a loose kneecap. 
Definition Trochlear Dysplasia

Trochlear dysplasia basically means that the groove for the kneecap have not become deep enough, since there is too much bone volume in the top of the groove. The definiton for trochlear dysplasia is an abnormal shallow, flat or even dome shaped groove. If you have trochlear dysplasia this can lead to both patella dislocation, anterior knee pain and cartilage breakdown. Your tendency to cartilage breakdown is based on too much load in this special part of the knee. Cartilage breakdown predispose to osteoarthritis. 

Why did you get trochlear dysplasia?

Basically we do not have the answer for this yet. However there is some heredity involved. But breech position during foetal life may also play a role. Once I was told by a patient having trochlear dysplasia and loose kneecaps, that in her family, loose kneecaps could be traced seven generations back. Sheila Strover can explain so it is more easy to understand - Click here.

Why is it of importance with this shallow groove?

Since humans are walking upright we have developed from other animals, and the result is that the thigh muscle constantly is pulling the kneecap outwards. To compensate for this high force, humans have developed this groove to provide the kneecap stability and containment. If the groove is missing the kneecap tends to go to the outer site - called a kneecap dislocation.

​Lateral Trochlea Inclination angle

The lateral trochlea inclination angle is regarded as the most important measurement for evaluation of Trochlear dysplasia. This angle says something about the osseous support for the kneecap. This is the angle of the outer part of the groove (Trochlea), compared to line in the back of the knee between the two femur condyles. In other words the more steep the outer edge of groove, the more stability it provides for the kneecap. A high angle prevents the kneecap for coming out of the joint. Further if the angle is below 11 degress it means trochlear dysplasia (shallow groove). Please notice the examples below - left is normal - right demonstrates trochlear dysplasia. Read more here.

Trochlear depth and trochlear asymmetry

If the trochlear depth is less than 3 mm or if the trochear asymmetry is less than 40% the trochlea is dysplastic. A trochlear bump may also involved in some cases.

Dejour Classification

Dejour is a very experienced and skilled orthopedic surgeon. He has made a classification based upon x-rays, having four subgroups. It contains Dejour type A,B,C and  D. Today we mainly uses MRI or CT scans instead of x-rays. And also since the classification is not so precise, it is slowly out-faded. Instead the lateral trochlea inclination angle have been more accepted. Also some other measurements can be used.

Patella Tilt

When your kneecap tilts, it is sometime because the outer kneecap ligament is to tight, but actually quite rare. Importantly your tilt is most often caused by trochlear dysplasia. When you have too much bone in the trochlea, consequently this causes your kneecap only to articulate on the outer part, as you might see below. Moreover this typically gives anterior knee pain or hyperpressure syndrome, based on to much pressure in the patellofemoral joint. In these cases trochleoplasty could be the right solution for you, since it reduces the pressure by unloading your joint. I some more rare cases is the patella tilt caused by increased femoral torsion - also called increased femoral anteversion.

Normal knee

Patella tilt - Trochlear dysplasia

Another Patella tilt - Trochlear dysplasia

TT-TG distance

This means Tuberositas Tibia - Trochlear Groove distance. The measure is done by CT or MRI scans. It explain how much offset the groove has in relation to where the patella tendon attaches to the tibia (Tuberositas Tibia). TT-TG distance is normally about 9 mm and if it´s more than 14 mm on MRI scans or 15-20 mm on CT scans, it´s too high. 

No Trochlear dysplasi

This is a MRI picture that demonstrates a slice of a normal knee, demonstrating the kneecap and the trochlear groove

Severe increased TT-TG distance on a CT scan in a knee having a degree of trochlear dysplasia

A drawing of how you measure the TT-TG distance. Two axial slices from the MRI or CT scan are overlapping or superimposed and thereby you can measure the distance.

Just a drawing of the same picture at left, demonstrating a TT-TG distance above 40 mm which is extreme. Dejour type D.


Bieder Anterior Posterior measurement

When you have trochlear dysplasia and you are troubled by patellar instability read more here if you are troubled by anterior knee pain read more here

If you want to read a scientific paper about the evaluation of trochlear dysplasia you can read this paper PDF Version

Cruciate Ligament Instability

The Anterior Cruciate ligament is a ligament that prevent the shin (tibia) to glide forward in relation to the thighbone when sudden changes of direction is done

Lesion to the anterior cruciate ligament do normally not heal by itself, unless it is sutured and enforced also called primary ACL repair. However some people are able to have a good active life with an ACL lesion. If correct physiotherapy is carried out, with good exercises in the correct order, it can be possible to improve both balance and reflexes to a degree that makes it possible to come back to previous level of sporting activity. Despite putting a lot of efforts into the rehabilitation, some patient will never reach sufficient stability and in those cases it is recommended to undergone reconstruction of the ligament. Today we know that those undergoing a reconstruction will have less risk of meniscal and cartilage lesions and less will need a total knee replacement compared to those who is not reconstructed. This is the background for patients below 18 years should have a reconstruction.

It can be difficult to make the diagnosis of ACL tears, but an experienced sports surgeon can often by only listen to the history and symptoms and do a ligamentous examination, and measure the site to site laxity difference with a device, give a precise diagnosis (see figure right). An alternative to this is an MRI scan, and by this also meniscal tears and cartilage lesions can be diagnosed

In Denmark approximately 2500 ACL reconstructions are done annually and the success rate is around 90 percent. The surgery is done by keyhole surgery. The most commonly used graft material is one or two tendons (Semitendinosis and Gracillis) also called the hamstrings tendon from the rear of the thigh.. Also the Patella tendon or Quadrips tendons are commonly used. Several other methods exist and here among Allograft tissue, however this is rarely used in Denmark.

The new ACL graft is pulled into the bone sockets in the femur and tibia. The graft can be fixed in many ways and continuously new improvements are done. This is the All insite ACL technique from Arthrex, using only the semitendinosus graft - see video

When can you do what after an ACL reconstruction? This is naturally individual, but typically crutches are used for the first 1 to 2 weeks after the surgery and full weight bearing is allowed. After 3 weeks it is normally safe to obtain car driving. Exercise bike can be started after 2 month and easy running after 4 month. It is not recommended to obtain contact sports before after 9-12 month and the physiotherapist needs to say OK.

Revision ACL reconstruction
Unfortunately a reconstructed ACL can get to long or brake. The most common reason for this is incorrect placement. In Zealand University Hospital, Koege and Aleris-Hamlet Parken, do we have the special assignment from the Health authorities to do these special revision ACL reconstructions. It is always more technically demanding, and commonly this requieres two surgeries. The methods for the surgery varies a lot and several factors play a role.


Every year 3000 to 4000 Danish inhabitants incur an ACL tear. Most commonly this occurs during soccer, handball or alpine skiing. The ACL rupture happens during a forceful twist.

Typically, it happens in soccer by a rapid change of direction in connection with a feint or during landing in handball after a jump shot or in twisting the knee during skiing, where bond is not triggered. Most feel a pop or snap in the knee and are rarely able to continue.

Over the next hour the knee will get significantly swollen. At the emergency room it can be difficult to diagnose cruciate ligament rupture and it is a type of injury that is often overlooked.

Video demonstrating a second look operation after primary repair of ACL six month beforehand. The anterior cruciate ligament has healed and the patient is happy and stable. The technique used is by Fibertape and Tightrope developed by professor Gordon McKay. 

Patellar Instability Overview

Patellar Instability Overview

A lax kneecap is a common disorder, and in the following text and subpages you can learn about this problem, but naturally it is not necessary for you to know everything there is to know in order to get treatment. (so warning - this is nerdy)
Symptoms of unstable kneecap

For some patients with kneecap laxity the kneecap will goes out once and they will experience no further problems. Others, however, may go on to experience repeated dislocations. If the kneecap has gone out more than once, it will have a tendency to out again and again. Then things may become quite disabling. The problem can occur while doing activities, like changing direction such as in sport or dancing. For others the kneecap just seems to go out without much provocation. This can happen while walking on uneven or slippery surfaces. In some of the worst cases you need to concentrate on avoiding the kneecap popping out the groove while kneeling. In some it can be a problem while jumping in and out of a car or even during sexual activity. 

Quality of life

Your quality of life can be significantly affected, since a lot of simple daily activities must be avoided. Sometimes your disorder also might cause pain during daily life. It is very important if you are going for surgery to rule out what cause your instabiliy. Your surgery should correct the identified abnormality (or abnormalities, since there may be several factors involved).

Why me?

It is very important to find out why your kneecap dislocated. This is since you can undergo so many treatments and in order for you to have the right one, this have to be examined. This is rather complicated. I have made a site only for explaining this in order for you to ask you surgeon the critical questions - click here

The many myths

Many myths exist about loose kneecap, and one is that you will grow out of it. Mostly this disorder is worse during the teenage years. Then you learn to be more cautious and reduce your level of activity. There is furthermore a tendency for the joint to get less flexible as you age and this helps the kneecap to stay in the groove. So many grownups do not actually grow out of the condition, but they just learn to avoid the activities that provoke the dislocation.

It is just going to be trained away

Another myth is that the disorder just needs to be trained away. This is only partially true. Some may perhaps be able to avoid surgery by learning to use their knee in a more correct way. This can be via physiotherapy and by strengthening the quadriceps and gluteal muscles. A special brace that supports the kneecap can stabilize the patella. There is yet no scientific documentation that say that physiotherapy can prevent further dislocations

Easy to treat - you just need a MPFL reconstruction

The next myth is that surgery can easily treat the disorder. A significant number of patients undergo surgery only to experience that the surgery did not work as intended. As previously mentioned, is of importance to explore the reason why the kneecap dislocates. I suggest that you as a minimum have an MRI can. Then your surgery can be individualized and thereby work efficiently.

It is hereditarily

The next myth is this disorder is inherited. Actually this is true in several cases, and sometimes a dislodged kneecap can be traced back several generations.

Sorry you surgery did not work

A further myth is that if you had once undergone surgery, and it did not work, that you just need to live with it. Unfortunately this is a disorder where many patient have undergone surgery using an insufficient method. This explains why it did not help or maybe even worsened the situation. Knowledge about this disorder has changed radically over recent years. If the right surgery is done, there is a very good chance for your knee to become significantly better.

What happens when the kneecap dislocate

When the kneecap jumps out it is naturally a very unpleasant experience. Often the kneecap has to be manipulated back at the emergency department. The first time the kneecap dislocates, a ligament on the inner side is torn. This is called the Medial Patellofemoral ligament or just MPFL. Such an injury causes a lot of pain and swelling. Sometimes a fragment of the knee cartilage is loosened. In some cases a loosened piece of cartilage requires surgery to fix the piece back in place or to remove it.

How much will I get troubled?

For those troubled by a continuously loose kneecap there will be a huge variability how much distress this actually causing. However questionnaires have been developed to help both patient and surgeon to elucidate the extent of the problem. Please see an example of a questionnaire here. As previously mentioned is it not always that the kneecap jumps out again. Nevertheless it can still be very troublesome since you may experience that it nearly jumps out. This is called subluxation.

The treatment of loose kneecap

The very first time the kneecap goes out, the treatment is likely to just consist of rest, ice, compression and elevation (RICE). You should be allowed full weightbearing and full range of movement. In past years a brace for support and immobilisation was generally used. Recent research has shown that it does not have any real impact. If the knee does not get the stability wanted and the kneecap continuously is feeling loose, a kneecap stabilizing brace or surgery should be considered. Physiotherapy has also been an important part of the treatment in improving muscle balance. Still we need studies that demonstrate that it has a positive effect. Please read more about surgery here; MPFL reconstruction - Elmslie-Trillat surgery - Trochleoplasty

The many names for unstable kneecap

The condition of a loose kneecap has many names and here you can learn more about: dislocating kneecap, kneecap out of its groove, kneecap out of its socket, kneecap malalignment, slipped kneecap, jiggly kneecap, unstable kneecap, recurrent patellar instability, episodic patellar instability, luxating patella, unstable patella...


The condition of a loose kneecap has many names and here you can learn more about: Dislocating kneecap, kneecap out of groove, kneecap out of socket, kneecap malalignment, slipped kneecap, jiggly kneecap, unstable kneecap, recurrent patellar instability, episodic patellar instability, luxating patella, unstable patella

Knee Injury Overview

Below you can read about the most common knee injuries other than meniscal tears, which are covered in a separate section.

Side ligaments
The inner side and outer side ligaments are also referred to as the medial and lateral collateral ligaments (MCL and LCL). Those two ligaments gives sideways stability - and those can be partially or totally torn by a knee twist. The treatment of the two ligament injuries is different.

The mediale collateral ligament normal heals sufficiently by itself in opposition to the lateral collateral ligament. The MCL tear is treated by a site to site stabilising brace, having normal range of movement and full weight support. Normally the MCL ligament is sufficiently healed to remove the brace after 6 weeks. The LCL is typically injured together with the ACL and the recommendation is always repair/reconstruct since the tears seldom heal by themselves.

Another ligament that has been given much attention lately is the Antero Laterale Ligament (ALL) and that is an important ligament that protects the knee towards too much rotation in relation to the femur. It can sometimes be needed to reconstruct that ligament simultaneous to the ACL reconstruction​.

Cartilage lesions
Cartilage lesions in the knee are common.The cartilage is a very important surface covering the bone. The cartilage is surprisingly most of all made of water and is extremely slippery in order to make the joint go smoothly and the cartilage is an important shock absorber. It is difficult to compare the cartilage with anything we know from daily life, but think about it as the peel from an orange. The cartilage can be torn off by a sudden twist or hit. The cartilage flake can float around in the knee as a loose body and cause sudden locking when it catches. The area where the cartilage is missing is a cavity, and potentially this can cause pain and mostly the knee will becomes swollen. Many cartilage lesions will slowly recover without any treatment, however some lesions continue to cause knee pain. Osteoarthritis in the knee is also a kind of cartilage lesion, however in this situation this is more a kind of cartilage thinning, based on decreased cartilage quality over time causing the cartilage to fragment and wear.

So at one end of the spectrum we do have cartilage lesions in the very young with fresh cartilage, and in the other end of the spectrum there is older people, where the cartilage starts to breakdown for more or less unknown reasons. In the middle between those types are all kind of variations. The treatment of the different types are different and this naturally makes this area of treatment very complicated. A lot of science is ongoing but still the big breakthrough is lacking. I am personally working with a study on Lipogems for treatment of osteoarthritis. This is micro-fragmented adipose tissue containing stemcells.

Treatment of cartilage lesions
Cartilage lesion in younger people (here is meant below 40 years) is typically treated by microfracture (Steadmann).

This is a treatment based on arthroscopic cleaning of the lesion and then small holes in the bone is applied to the button of the lesion directly into the bone. This causes some of the bone marrow and blood to float into the defect and fill it. Over time this will mature into some cartilage looking scar tissue. When such a treatment is done, the knee must not be loaded for 8 weeks, since the area has to mature in order to stand the forces. It normally takes one year before the repair tissue is 100 % healed. Unfortunately does about ⅓ not heal and in those cases a lot of advanced methods exist.

The most famous is cartilage transplantation (autologous chondrocyte transplantation - ACI). This method was started already in 1987 by Mats Brittberg and is therefore a well known technique that has been refined many times. Most people ask why not start with this instead of microfracture? The short answer is that it is troublesome and very costly and the results are only minimally better. By cartilage transplantation we harvest some cartilage and this is then regrown for some months, and then the cartilage cells are transplanted into the defect by another operation.There has been attention drawn to the issue that some cartilage lesions never heal because of underlying malalignment and axis deviations. Those knees must have they imbalances simultaneous corrected by osteotomies - see for example tibia osteotomy or trochleoplasty or tibial tubercle osteotomy.

Plica synovialis enlarged

All knees do have a plica placed on the inner site of the kneecap (parapatellar) and one in the front of the knee (infrapatellar). The inner plica has no know function, but is a residual from the fetal life. Sometimes a knee impact or wrong use of the knee can cause this plica to get inflammed and the it gets swollen and catch between the kneecap and the femoral condyle. The treatment focus rest and antiinflammatory medicine (NSAID or steroids. When the plica has restored it self, a physiotherapis can help by restoring balance and correct movement patterns to prevent recurrence. Sometimes those treatments are not sufficient and the medial plica has to be taken care of by arthroscopic surgery, where it easily can be removed.

The infrapatellar plica is attached to the Hoffa Fad and moves significantly when the knee straightens and bends. Sometimes scar tissue in the plica can cause anterior knee pain based upon scar tissue in the plica - read more here

Plica synovialis
Osteoarthritis in the knee

Osteoarthritis in the knee means wear and damage of the cartilage. For more or less known and unknown factor the cartilage becomes thinner and in a bad quality situation. Some people seems not to be very affected until it gets really severe, while others are very troubled already when the wear situation starts. In my opinion this can be explained how the synovial tissue, that contains all the nerve endings, responds when the microscopic cartilage particles are going to be reabsorbed from the knee. For a small proportion of people, the synovial tissue will get swollen and painful already when it gets in contact with a small amount of cartilage particles and for those the symptoms of osteoarthritis will start concomitantly to the wear starts. This can be very frustrating since you cannot see the osteoarthritis in X-rays and MRI in the early phase of osteoarthritis. For most people the symptoms of osteoarthritis will first appear when the wear is more pronounced. The typically symptoms will then be pain after activity and night pain  Many known and unknown risk factors for osteoarthritis exist. First of all is previous injuries such as meniscal tears, cruciate ligament tears, cartilage lesions, bowed legs and fractures of importance. Also more intrinsic factors like heritage and nutrition (D-vitamin) are of importance. 

Prevention of osteoarthritis in the knee

How can you prevent further degenerative changes in the knee? First of all are you going to live a healthy live and keep your weight down. You shall avoid activities that implies a lot of stresses in the same part of knee. This could for example be walking long distances or running, when the forces are applied to the same small spot in the knee for every step. Contrary to this is activities like bicycling, rowing and swimming that are much more healthy for the knee. Actually is activity of importance for bringing fresh joint fluid to the cartilage and for this is bicycling very healthy. In cases with malalignment, meaning that something in loaded in the wrong way, it can be preventive to have surgical correction of the deformity. This is the situation when you are bowlegged or when you kneecap is tracking crooked or irregular. See Tibial osteotomy or anterior knee pain 

Loose body

This is a little piece of cartilage that is floating in the knee. It can sometimes be caught between the condyles. It can easily be removed by an arthroscopy. It can not alway be seen on MRI´s or X-rays

Baker cyst

Baker cyst´s or Popliteal cyst´s are liquid in the rear site of the knee Are you troubled by a Baker cyst there is about 90 % risk, that it is caused by a knee injury, such as a meniscal tear, cartilage lesion or an ACL rupture. If you are one of those without such an injury, don't let anyone remove your Baker cyst by open technique from the rear site of the knee, since there is a 60 % risk of relapse. The background for developing the cyst is a plica in the rear site of the knee, that both produce liquid and act as a valve, meaning that the liquid runs to the rear site into the cyst, but it cannot escape. If the cyst does not disappear by empty it and installing steroid, you need to have the cyst removed. For this you need to have a special arthroscopic procedure with removal of the plica in the rear site of the knee. Eventually read more here

Kneeguru have made a little paper on this - just click here​

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There exist many types of knee injuries and here is anterior knee pain, jumpers knee, runners knee and pes anserinus pain, some of the most common, and those could be caused by overuse.

Dislocating Patella

Unstable kneecap or dislocating patella is a common disorder and here you can read more about why your kneecap has become unstable.

For some patients it happens once in a lifetime and after that they have no problems.

For others the kneecap continuously dislocates or subluxate. If the kneecap has been dislocated more than once, it tends to become dislocated again and again, and then of course it becomes quite troublesome. Here you can read more about why you kneecap becomes unstable

I recommend you to either before or after having read this - go to the section Patellar Instability overview.

Why does the kneecap dislocate?

There are many reasons why the kneecap becomes unstable and the four most important will be explained beneath. Some very complicated words are involved like Trochlear Dysplasia, Patella Alta, Increased TT-TG distance and increased Femoral Antetorsion, but as said this will be explained. Occasionally the kneecap is struck by a foot or something else on the inner side so hard that it pushes the kneecap out, but mostly it is a sudden twist or turn that makes the kneecap go out.

Here you can download a PDF file from a Webinar

Here you can see and listen to the Webinar - Link


Flat groove - Trochlear Dysplasia

 The most common reason for the kneecap to dislocate is that the groove (trochlea) which patella runs in when the knee is bent is either shallow, not deep enough, or dome shaped (this is called trochlear dysplasia and there is a section only for this). If the kneecap is not contained (kept in place in the groove), the patella will have a tendency to jump out, to the outside of the knee. Among those who have experienced the first kneecap dislocation and who have a shallow groove (trochlear dysplasia) two-thirds will experience another dislocation. If you have a normal groove, in contrast, the risk will only be one-third.

Why the trochlear groove is flat is that it for unknown reasons at birth it is filled with too much bone underneath the cartilage.

3D reconstructions of a normal knee to the left and a knee with a shallow groove on the right.
MRI demonstrating two different knees. On the left it is normal and on the right the groove for the kneecap is missing (Dysplastic)
Patella Alta

Patella Alta means that the patella is too high and this is an important factor for loose kneecap. If the patella is too high there is a huge risk that, at the point where it should locate itself in the groove, it will instead go to the outer side of the groove, and dislocate. Below you can see an MRI scan with a high riding kneecap.

MRI and Patella Alta

High kneecap

Distalisation of the Tibial Turbercle for normalizing anatomy

Distalisation Tibial Turbercle
Increased TT-TG distance

Increased TT-TG distance means that the Tibial Tubercle is unusually far to the outer side of the shinbone and that causes the kneecap to track outwards. This will give a tendency to pull the kneecap out of the groove and thereby dislocate or subluxate. Often the increased TT-TG distance is caused by Trochlear Dysplasia since this makes the groove go towards the inner side (yes it is right inner side and that makes the TT-TG distance increase). In those cases where the Tibial Tubercle is rotated outwards, the treatment will consist of a Tibial Tubercle Osteotomy

Increased TT-TG distance
Trochlear dysplasia

This demonstrates and axial view on CT scan or MRI scan were both the Trochlear Groove (TG) and the Tibial Tubercle (TT) are visualised. The distance between those is normally close to 9 mm - if it is above 20 mm it is far to high.

Increased Femoral Antetorsion

In some cases the patella dislocates secondary to a malrotated hip which makes the knee go inwards (increased anteversion of the femur). By clinical examination this can be suspected and in these cases a CT or MRI scan can confirm the diagnosis. The malrotation can be corrected by a femoral rotational osteotomy. Beneath you see a figure demonstrating a left femur with severe increased internal rotation, causing the patella to dislocate. The patient had previously had a failed MPFL reconstruction. She responded very well to a combined femoral rotational osteotomy and a revision MPFL, and her pain resolved completely when the internal fixation device was removed a year after.


Typically the kneecap dislocate doing activities with changing direction, such as sports or dance. In others, it feels as if the kneecap is coming out just by walking on uneven surfaces. At worst you should concentrate if not kneecap is out of joint when doing squat or getting into and out of a car. Quality of life can be significantly affected because it discourages one from many activities.

MYTHS OR REALITIES?

It is a myth that it is easy to deal with by doing an operation. Quite a few patients have been operated unsuccessfully, and some even several times. It is therefore important to find the true cause of the kneecap is out of joint by an MRI scan and X-rays. Then the operation can be individualized in order to reestablish normal anatomy and then the operation will be effective.

Another myth is that it is hereditary and this is in fact often not a myth but true. Sometimes dislocating kneecap can be traced several generations back.

The next myth is that you just have to live with the problem, if it is the case that you already had surgery and the surgery has not worked as intended. Knowledge about the cause of the disorder and the treatment of it has changed radically over the last few years.

Anterior Knee Pain – can it be treated surgically?

The condition of having anterior knee pain is a very common disorder. The majority of patients can successfully be treated without surgery.

First of all is Anterior knee pain a symptom and not a disease. Today we have identified many reasons to have anterior knee pain. Initial treatments of your Anterior Knee Pain (AKP) or Patellofemoral Pain (PFP) consists two thing. First of all is a reduction of level of activity. Next is a mixture of physiotherapy-guided quadriceps and hip exercises, core stability training, and eventually foot orthoses, braces and tape, can be helpful. If you are have chronic anterior knee pain for several years you should read further. You have likely been told to live with your pain by your doctor. Or an orthopedic surgeon have introduced the good model "Functional Envelope" developed by Scott Dye. But in your specific case you think, that is not the best option. If so you should read more since surgery might be scary but it could be an option. 

Surgery for anterior knee pain?

Surgery for anterior knee pain is very complicated and you should look for a surgeon with a special interest in the patellofemoral joint. It has to be a surgeon who you can trust. The surgeon also have to examine you competently. Also the surgeon needs to explain to you exactly the MRI. I normally say that "there is nothing you cannot operate on without risk of making it worse". So be alert and skeptical to what your surgeon might suggest you.

Second opinion

Eventually get a second opinion from another patellofemoral surgeon - not just a standard orthopaedic surgeon. You are also welcome to book at Skype or Whatsapp consultation with me for 150 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.

Possible surgical solutions
  1. Arthroscopic debridement
  2. Arthroscopic plica resection (read here) 
  3. Lateral retinaculum lengthening (or lateral release) - se below
  4. Tibial tubercle medialisation (Fulkerson osteotomy)
  5. Distalisation of the tibial tubercle
  6. Arthroscopic trochleoplasty
  7. ​Lateral patella facetectomy
  8. Femoral derotation osteotomy - se below
  9. Tibial derotation osteotomy
  10. Patellofemoral cartilage restoration
  11. Resection arthroplasty
  12. Patellofemoral arthroplasty
Arthroscopic debridement

Arthroscopic debridement can occasionally be a solution. If the knee is locking or catching and there is no malalignment. This means that the kneecap is tracking normally in the groove.


Chronic anterior knee 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. For a group of patients having severe chronic pain, a number of anatomical factors can cause the patella to maltrack or cause the pressure in the patellofemoral joint to increase. These issues can stress the cartilage (chondromalacia patellae) and this can cause inflammation or increased pressure that eventually leads to pain.

In case you would like a second opinion regarding your MRI or just your general knee situation, I do Skype consultations. The cost is 150 euro - email [email protected]

Is there a relationship between AKP 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

The Scandinavian Congress on Sports Medicine 2018 - take a look at the symposium on anterior knee pain on this youtube video

Lateral retinaculum lengthening

If you are one of those troubled by chronic anterior knee pain it might be that you are having hyperpressure syndrome. This is mostly caused by a tight lateral retinaculum (a kind of ligament that stabilise the patella - see image). 

Tilt of your kneecap

When your retinaculum is tight, this can cause the patella to tilt. Often this tilt can be seen on an MRI scan. A lateral lengthening can in these situations often help to unload the cartilage forces and thereby reduce the pain. You should always undergo an MRI scan to rule out if the tilt is caused by trochlear dysplasia. If you have a lateral release in these cases, there is a risk of making the kneecap unstable, making it subluxate or even dislocate.

The medial and lateral retinacula (singular=retinaculum) help to stabilise the patella

Lateral lengthening technique

Lateral lengthening or release is a name of an operating technique. Here the outer ligament for the kneecap - which has two layers - is lengthened. You see the technique below, first is both layers splitted. Then they are cut in different places, so that the final result is a lengthening.

Anterior knee pain and tibial tubercle osteotomy

Anterior knee pain can in some cases be helped by unloading the patellofemoral joint via the procedure of transposition of the tibial tubercle (TTT), either medially (Elmslie Trillat osteotomy) or anteriorly (Fulkerson osteotomy) - again depending on the MRI findings. If the tibial tubercle is externally rotated, it can be a good idea to have this corrected.

In some patient anterior knee pain is caused by a high riding kneecap (patella alta) and this can also be corrected by doing a distalisation of the tibial tubercle, ,that is moving it downwards.

Fulkerson Osteotomy
Fulkerson Osteotomy candidate

Here you see light patellofemoral osteoarthritis and patella tilt and patellar overhang. The patient responded well on a Fulkerson Osteotomy and lengthening of the laterale retinaculum

Patella Alta

Patella Alta means a high riding patella. The result is that on bending your knee the kneecap reaches the trochlea groove too late, and the result is increased wear of your cartilage on the rear of the kneecap - this causes pain. The problem can be helped out with a distalisation of your tibial tubercle, efficiently pulling the kneecap down into a better position to engage in the groove at the right time. So your pain starts since there is too much stress on your cartilage between the patella and the groove for the kneecap. When your patella sits high, there will be very little overlap between your patella and the trochlear groove, this means that your pressure per square centimeter of cartilage is very high. When your patella is brought back into the trochlear groove, your pressure is actually reduced - and this is in opposition what you as well as many surgeons may think. Read more here

Hoffa Fat Pad Impingement

Hoffa Fat Pad Impingement is a very common explanation for having anterior knee pain. However Hoffas Fat Pad Impingement is not a diagnosis, but something seen on MRI. Hoffa Fat Pad Impingement is cause by maltracking of the patella into the trochlear groove and in most circumstances is based upon Patella Alta or trochlear dysplasia.

Plica Synovialis The parapatellar plica and Infrapatellar plica is closely related to the Hoffa Fat Pad and often the pain is more related to those two plicaes and not the Hoffa. Read a little more about the plicaes here

Fad Pad Impingement - see more here

Corpus Hoffa is seen as orange

References for Hoffa Fat Pad Impingement

1            Matcuk GR, Cen SY, Keyfes V, et al. Superolateral Hoffa fat-pad edema and patellofemoral maltracking: Predictive modeling. Am J Roentgenol 2014;203:207–12.

2            Tsavalas N, Karantanas AH. Suprapatellar fat-pad mass effect: Mri findings and correlation with anterior knee pain. Am J Roentgenol 2013;200:291–6.

3            Widjajahakim R, Roux M, Jarraya M, et al. Relationship of Trochlear Morphology and Patellofemoral Joint Alignment to Superolateral Hoffa Fat Pad Edema on MR Images in Individuals with or at Risk for Osteoarthritis of the Knee: The MOST Study. Radiology 2017;284:806–14.

4            Luyckx T, Didden K, Vandenneucker H, et al. Is there a biomechanical explanation for anterior knee pain in patients with patella alta?: influence of patellar height on patellofemoral contact force, contact area and contact pressure. J Bone Joint Surg Br 2009;91:344–50.

5            AL-Sayyad MJ, Cameron JC. Functional outcome after tibial tubercle transfer for the painful patella alta. Clin Orthop Relat Res 2002:152–62.

6            Jibri Z, Martin D, Mansour R, et al. The association of infrapatellar fat pad oedema with patellar maltracking: A case-control study. Skeletal Radiol 2012;41:925–31.

Anterior Knee Pain and increased femoral anteversion and/or increased tibial external rotation

A malrotated hip, making the knee go inwards (increased anteversion of the femur) can also lead to anterior knee pain due to increased forces on the joint. It needs to be ruled out by clinical examination and in severe cases by a CT scan or special MRI scan. The malrotation can be corrected by a femoral derotational osteotomy. Beneath you see a figure demonstrating a left femur with severe increased internal rotation, causing the patella to dislocate or maltrack causing pain on the outer site of the kneecap. Sometimes the tibia is also involved having too much outer rotation and this also needs correction by a tibia derotational osteotomy - either alone or in combination with a femoral rotational osteotomy.

A malrotated hip, making the knee go inwards (increased anteversion of the femur), can also lead to anterior knee pain due to increased forces on the joint. It needs to be ruled out by clinical examination and in severe cases by a CT scan or special MRI scan. The malrotation can be corrected by a femoral rotational osteotomy. Beneath you see a figure demonstrating a left femur with severe increased internal rotation, causing the patella to dislocate or maltrack causing pain on the outer site of the kneecap.

This image is looking up the femur bone, from the knee up to the pelvis. The left femur (to the right of the image) shows that the shaft of the femur is rotated inwards compared to the other side. The this patient responded well on femoral rotation osteotomy.

Arthroscopic trochleoplasty 

Maybe your Anterior knee pain is caused by severe trochlear dysplasia. If you have trochlear dysplasia you are having too much bone in the groove containing the patella. The groove can be flat or dome shaped and consequently this can increase your pressure in the joint. By unloading the joint pressure by an arthroscopic trochleoplasty this can likely reduce the pressure and consequently your anterior knee pain. Please check this paper

Arthroscopic Trochleoplasty

Trochlear Dysplasia 

Before trochleoplasty

Imidiately after trochleoplasty

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

Patellofemoral resurfacing prosthesis

The Hemicap wave prosthesis in an inlay type. It is my experience that by reaching the knee from a lateral approach (outer site of the knee cap) you will get fast recovery and there is full weightbearing from day one. The surgery is performed as one day surgery and often you will be able to drive a car safely after 3-4 weeks. Read more here

Patellofemoral prosthesis Hemicap Wave

Below you see the Hemicap Wave prosthesis for severe patellofemoral osteoathritis. I have very good experience using the inlay prosthesis. The surgery is performed by one day surgery and you are allowed free range of movement and full weight bearing from day one. Read more here

Patellofemoral osteoarthritis

In cases of symptomatic osteoarthritis in the patellofemoral joint, several options exist. Some patient may have symptoms relief by a lateral lengthening, a lateral patella facetectomy, a TTT or a trochleoplasty or cartilage procedures such as microfracture or autologous cartilage transplantation and finally some patients needs to be treated by a patellofemoral prosthesis. Treatments with stemcells is on the exprimental level and right now we are testing adipose stem cell transplantations.

Anterior Knee Pain and Trochlear Dysplasia and osteoarthritis

In some special selected cases I have done a "Resection Arthrosplasty". This is in cases with severe anterior knee pain, trochlear dysplasia and arthritis. Alternative to a prosthesis, a new groove to the patella is made. Apparently this unloads the patella in such a degree that the pain diminishes significantly. Download the Editorial paper from the KSSTA journal by clicking below.  

Resection Arthroplasty

before

after