I wonder if the necrosis is the right diagnosis. There  are no sufficient subchondral bone lesions to explain the "flattened cartilage". Maybe is it simply a patella femoral syndrome .

Thank you Olivier. In fact, I also wonder if it is the right diagnosis or if it is a bone marrow edema in reaction to a cartilage injury.

Nevertheless, it seems to be affecting greatly the patient, with limping, affecting the sleep, not very usual for a patellofemoral syndrome. Have you seen this type of images for that pathology?

Arthroscopic look will give more details. Anyway, early stage of Koenig's disease is possible.

What else would you do in the arthroscopy Panayot? Core decompression? 

night pain Is common in PF syndrome. Artroscopy is not recommended in This case. According the Poor information given by Mri and the absence of any severity and gravity You Will have nothing to see during arthroscopy. I would propose to xzir before to propose any agressive treatment

Dear Juan, 

Core decompression is not applicable for medial condyle osteonecrosis at all? We are talking about the knee not the femoral head, don't we? Arthroscopy  may reveal idiopathic chondrolysis for example or other initial cartilage damage ? May be used for shaving or Pridie's piercing of the lesion. 

Dear Juan, I am agree with Olivier,

Dear colleagues,

The information about this case is really insufficient. The duration of complaints is also relatively short. I do not accept the hypothesis of patellofemoral pain syndrome at all.  Sorry, but night pain is not typicall.  The leading symptom of patellofemoral pain syndrome is knee pain around the patella, especially when the patient is sitting with bent knees, squatting, jumping, or using the stairs (especially going down stairs). The patients may also experience occasional knee giving away, in which the knee unexpectedly buckles and does not support your body weight. It is also common to have a catching or grinding sensation when you are walking or when you are moving your knee. This symptom together with pain can be provoked when the physician presses the upper pole of the patella and urges the patient to actively contract the femoral quadriceps muscle. In this case one should focus on the changes in the medial condyle and eventually put them under monitoring. I am curious to see control images in 2 months, because the MRI changes at the moment are really very obscure.  

I agree with Dr Tanchev,  The notable point is relatively healthy medial knee compartment sans osteoarthrosis changes given the age of patient and that may predict better recovery whatever the treatment.

I would observe the patient while protecting weight bearing .I've a patient who presented like this who went on to devevope avascular necrosis of MFC. The  diagnosis was Polycythemia previously undiagnosed. He did extremely well following core decompression and medical management. Followup MRI is negative repeated twice.

I don't agree with Dr Tanchev on one pint : night pain is common (but not constant) in patellofemoral syndrome for one obvious reason : many people sleep with flexed knees,  this creates the same situation as sitting position. But patients don't speak spontaneously. The rest of description of PF syndrome is absolutely correct.

Not sure the diagnosis is osteonecrosis. The oedema is mostly as it is shown in the pictures mostly just over the anterior third of the medial meniscus, as a mirror view, suggesting a mechanical influence of this structure. It reminds me the postmeniscectomy oedema sometimes we see, o those due to an hypermobile meniscus. I would just quit the load, may be PRP without leucocytes, and repeat the MRI in 3-4 weeks.

I had experience with hialuronic acid and repeat the MRI one year after.

I have seen numerous cases like this.  My approach would be to perform an intraarticular saucerization (reshaping of the medial femoral condyle) using superior and inferior arthroscopic portals.  Debridement of the meniscus.  Chondroplasty of the condyle and patella.  Aspiration of bone marrow from the ipsilateral iliac crest (you may concentrate....but usually not necessary).  I would then inject the BMA into the edema site causing the fat to be expressed therefrom.  Close my incisions and place the knee in a brace with a valgus load.  Keep the knee extended for 3 weeks with toe-touch WB.  

Injecting these lesions with cement provides immediate relief in some patients, but the symptoms usually recur.  These knees need an all biologic solution.

don't Forget gentlemen That we have a patient with one month duration pain and not really consistent anatomical lésions. In absenceof any emergencyI suggest to wait to months before any "agressive" therapeutic décision.

Again, I have many many years experience with these kinds of lesions.  This is Atypical Avascular Necrosis (Osteonecrosis).  The problem is most orthopedic surgeons do not make this diagnosis with VERY obvious findings are observed.  The images posted do NOT show the findings that would allow me to conclude that osteonecrosis is present.  I look for "mixed-signal heterogeniety" on the sagittal T1 weighted images.  There will be a salt-and-pepper appearance in the distal femoral sulcus.  This area represents occluded marrow spaces.  These occluded marrow space induce collateralized blood flow that is observed as "oedema."  This is what is observed on MRI and the real cause of the edema goes unnoticed.

I agree with Dr James, but can we use PRP for this edema site? @james

Greetings,  the dialogue is good.  I do NOT recommend PRP.  There is insufficient data to support PRP, and although the same is BMA, its use would be considered more reasonable.  One must avoid injecting cement into these lesions.  Some may argue that the cement is "resorbable," the problem is it was deficient biology that led to the lesion.  Thus, it would be unreasonable to expect that sufficient biology would exist in a diseased knee to resorb the cement.  I have had many years of experience with these lesions and the case shown demonstrates the described findings as well as medial subluxation of the meniscus with ANTEROMEDIAL impingement.  I would suspect a degree of hyperextension of this knee.  If these kinds of considerations are NOT considered, these knees do NOT do well irrespective of what is done surgically.  I would additionally note that the degree of impingement has contributed to the oedema.

Notice that the x-rays also show the osteochondral lesion. I thank all of you for comments. The patient doesn't want surgery and he is getting better with conservative management. He has decreased activities, decreasing weightbearing.

I think that the symptoms are related to this non-traumatic osteochondral lesion. The meniscus has little extrusion but doesn't have any tear.

I have one question for you. Do you think the osteochondral injury happened first and we are looking at bone marrow edema secondary to it, or do you think this is osteonecrosis with secondary chondral involvement?

The temporal relationship is important, but if it does not alter the way we think about these lesions, such determination loses value and simply becomes talking points.  My first post noted that this case is consistent with Atypical AVN.  The cancellous bone with occluded marrow spaces goes unnoticed because it does NOT have the classic Steinberg findings....that said, the cartilage changes result from the brittle necrotic bone.  As suggested in the 70's by Pugh, Radin, and Rose at Harvard, the loss of ductility of cancellous bone (thickened trabeculae) may contribute to the destruction of the overlying cartilage.  The problem has been the diagnosis of OCD by most, as a PRIMARY problem.  While this may be true, it is not common, and I would not suspect such in a 60 yo patient.  That said, my focus is on the underlying bone and unless there are specific traumatic events, the patient is considerable athlete.....the articular disease is secondary to the primary bony disease.  I note the substantial osteopenia along the medial femoral condyle in the posted x-ray....all of which is consistent with my initial post.  A period of NWB is expected to be beneficial.  The meniscus is subluxing because osteophytes are developing along the medial femoral condyle

AVN early stage. First ischaemia or venous stasis of subchondral bone, then cartilage engagement.

Is the meniscal root intact? 

So...Bone marrow oedema....Stage-I of AVN

My first thought, because there is no trauma, is that this is "pain of unknown origin" and that the knee pain is a symptom and not necessarily where the problem really lies.

First thing I would do is check out the hip joints, both sides, for any restriction in hip flexors (extension motion) or external rotators (internal rotation motion).  Knee pain is frequently a result of limitations in the hip joint including (usually) motion of the opposite hip. 

I would also check out knee extension for any tightness of the hamstrings at insertion and gastrocnemius at origin.  I do this side-lying on opposite side of symptomatic knee, bottom leg straight (for starters) and in neutral hip, symptomatic leg resting on a roller or pillows high enough for hip to be in neutral vis a vis hip ab/adduction., knee flexed at 90 if possible.  Have patient actively straighten knee and measure lack of extension.  Then, because there is usually limitation, extend the hip for a few degrees and measure.  Keep doing this until knee can extend fully.  This is side-lying straight leg raising.  Once you can extend  knee fully, bring knee into full extension and have patient dorsiflex same ankle by pressing out through heel.  Chances are there is tightness at origin of gastrocnemius. Just to be complete, do testing on other side also.  If the knee checks out ok with the opposite leg straight, bend the opposite knee to full motion and try again.  This makes a difference in knee extension on the other side.

I would then prescribe exercises to correct limitations, strengthen musculature of hip and knee.

There is more to this but this is where I would begin.   I have found many, many patients with knee pain of unknown origin who have significant restriction in the posterior knee and also of opposite hip.

Thanks for the opportunity to share.

Sara Meeks

I think it is bone marrow edema