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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. But why do I have this strange pain? Can something be done? Are you curious, then read more.
Anterior knee pain - a disease?

First of all is frontal 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 ( also called Patellofemoral Pain consists two things. First of all you should try to reduce your level of activity. Next you have to try a mixture of physiotherapy-guided quadriceps and hip exercises. You should also train core stability, and eventually foot orthoses. Braces and tape, might be helpful. If you have tried all that, and that you still have chronic anterior knee pain you should read further.  

Living with pain

I guess You have been told several times to live with your pain since there is nothing wrong. Eventually you have been introduced to the model "Functional Envelope" developed by Scott Dye, or you have just by experience automatically adopted your level of activity. That solution might be fine, but in your specific case you might think, that if something could be done that would be great. It´s likely that you often have been deprecated surgery.

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 - if it´s difficult to find someone locally try www.kneeguru.co.uk and ask for help in the community.

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. Tibial varus osteotomy
  11. Patellofemoral cartilage restoration
  12. Resection arthroplasty
  13. Patellofemoral arthroplasty
  14. Lateral release reversal

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.

What causes the pain

For a group of patients having severe chronic pain, a number of anatomical factors can cause the patella to track in a wrong way. Sometimes also the pressure in the patellofemoral joint is increased. Together can these issues stress the cartilage (chondromalacia patellae). This can cause inflammation that eventually leads to pain.

KneeGuru.co.uk have in cooperation with me created an Ebook, describing things much better than I am able to do - download this from free here

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. 


Arthroscopic debridement

Arthroscopic debridement can occasionally be a solution. If the knee is locking or catching and there is no malalignment. (Meaning that the kneecap is tracking normally in the groove.)  Sometimes the cartilage on the rear side of the patella is uneven and the it might help to smoothen the cartilage. During the arthroscopy concomitantly plica resection can also be carried out (read here) , Arthroscopy is a very minor surgery and a skillful arthroscopist seldom makes things worse. Ask the surgeons about infrapatellar and lateral plica - if the surgeon ignores you, consider finding another surgeon.

Lateral retinaculum lengthening

If you are one of those troubled by chronic anterior knee pain it might be that you are having hyperpressure syndrome. In hyperpressure situations you typically have anterior knee pain, when your knee is bent for too long. This is mostly caused by a tight lateral retinaculum. (a kind of ligament that stabilise the patella - see image). Previously we did lateral releases, but today we try to avoid this. Instead we now use lengthening, since this gives better results. This is small surgery and seldom things get worse. Read more about kneecap tilt and the procedure below.

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.

Lateral release reversal

Lateral release can sometimes result in medial patella instability. For the patient, this is a very troublesome situation. Luckily is lateral release a more and more seldom procedure. The clinical diagnosis is very easy if the surgeon gets the idea and know what to look for, nevertheless is this condition of medial instability often overlooked. The lateral release reversal is a relative simple surgical procedure, with reconstruction of the lateral retinaculum by using a part of the tratus ileotibialis tendon.

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.

Relative often anterior knee pain is caused by a high riding kneecap (patella alta). This can 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. This increases tje wear of your cartilage on the rear of the kneecap. This causes pain. There is too little overlap on your cartilage between the patella and the groove for the kneecap. See figure on the right. This means that your pressure per square centimeter of cartilage is too high. Similar to high heeled shoes that spoils the flooring. When your patella is brought back into the trochlear groove, your pressure is actually reduced. This is in opposition what you as well as many surgeons may think. Read more here

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.

The yellow demonstrate the overlap between the cartilage on the lower part of the patella and the cartilage on the trochlea groove. If the overlap is little will the pressure on the cartilage be high. Some might think that the pressure increase when the kneecap is pulled down - however it is just opposite.

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

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

A malrotated hip, making the knee go inwards (increased/decreased 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 a 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.

Chronic patellofemoral pain

This young woman had chronic anterior knee pain. I asked her to put the kneecaps in the front. She was not aware her legs were a different from others.

Chronic AKP

This young woman had chronic patellofemoral pain for years based upon 'miserable malalignment' also called 'torsional malaligment' She had been referred to a psychologist since she nothing was wrong. 

Increased femoral anteversion examination

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.

Tibia varus osteotomy

In seldom cases can a person who are kneed be troubled by anterior knee pain and pain on the outer joint line. Here can an osteotomy that makes the leg straight be a good option.

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