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I am curious to know if forum members are performing Arthrocentisis on foot joints to investigate joint effusions suspicious for crystal deposition arthritis. Most of the literature I have read indicates that microscopy of synovial fluid is by far most reliable diagnostic approach yet I have yet to come across a patient who has a reported history of foot involvement with gout, who recalls having had a aspiration of the foot joints. Whenever I refer a patient with suspicion of gout to primary care physician a blood test for uric acid level is ordered and diagnosed seemingly based on this.

So my question is: as podiatrists if we perform arthocentisis and microscopic examination with polarised light microsope for presence of crystals what might our medico-legal postion be regarding training and accreditation for this proceedure. I was not taught this in my undergrad training and I reason that this is the only reason that I do not perform this test presently. The microscopy seems quite straightforward ard I would think this would be an easy test to learn and be accredited for. Are the DPMs out there doing this as routine part of their practice, if so both specimin collection and microscopy?


cheers



Martin

The St. James Foot Clinic
1749 Portage Ave.
Winnipeg
Manitoba
R3J 0E6
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

The various crystaline arthropathies can be verified via synovial fluid analysis or primary inspection.
Many,of course, need only clinical examination, especially when acute. Acute gouty arthritis is pretty hard to confuse with anything else. When surgically debriding 1st MTPJs or ankles, it is always obvious if the patient has gout. Not only because of tophi but the cartilage has unique silver/white scales.
Dr S Arbes

Dr S Arbes thanks for your reply.

You mention that you feel gout is easily diagnosed by clinical exam.

How would you differentiate the following case of acute onset monoarthritis which I saw in my clinic last week.

42 yrs old male warehouse worker - occupation requires constant standing and walking at work, sudden onset right foot 2nd metatarso-phalangeal joint pain 2 days AFTER stressing foot, patient reports "feeling something give" at site, prior history of gout in knee several years ago not taking allopurinol. denies STDs

O: right foot dorsal 2 and 3rd metatarso-phalangeal joint redness and swelling. Pain at extreme of 2nd metatarso-phalangeal joint range of motion which is very limited. no pain with resistance testing of intrinsic toe flexors/extensors which show normal strength. radiographs showed no significant findings, Diagnostic ultrasound exam shows significant 2nd metatarso-phalangeal joint effusion with flow with power doppler. blood work showed no significant findings for uric acid or sed rate.

A: differential diagnosis; gout, CPPD or other crystal deposition, traumatic arthritis, infection

thanks

Martin

I have found the clinical signs of acute gouty arthritis rather distinctive. The color; red/purple/shiny/localized to joint area cannot be confused with infection/cellulitis (at least after you have seen a few hundred!)
Historically your patient has a traumatic etiology; perhaps stress fracture which has progressed to a true fracture; acute flare-up of a previous osteochondral defect or fracture; isolated acute tenosynovitis, etc.......
Frequently I have found the UA level DURING an acute attack to be normal (since much of the excess Uric Acid is now intra-articlular). I normally inject 3 cc's of 2% xylocaine plain around the Posterior tibial artery at the level of the tarsal tunnel (for acute gout) - the vasodilatory effect of the xylocaine helps decrease the amount of intra-articular UA (and it's nice to have the foot numb for instant relief.)
Pain around the 2nd MTPJ can usually be classified as articlular or, more commonly, plantarly at the level of the 2nd proximal phalangeal base. Palpation of the base, plantarly, will usually send the patient off the exam table!
In addition, merely chronic synovitis as you know, can have an acute episode. I frequently, after all else fails to render long term relief, surgically debride these. It's always amazing how much synovitis can fit into a small MTPJ.
Hope this helps...let me know how your patient does.
Feel free to continue our dialog.
Steve

Hi Steve

Thanks for your thoughts.

My clinical reasoning to date is as follows;

Precipitating cause of problem appears to be trauma (see prior description).
Diagnostic ultrasound exam is fairly unequivocal but non specific for arthritis.

I have attached annotated diagnostic ultrasound images to show this, power doppler shows flow within hypoechoic area, which is compressible and has no communication with EHL tendon sheath. Peri-articular structures including plantar plate appear normal.

An interesting feature of the Diagnostic ultrasound exam, which I am not able to interpret confidently, is a hyperechoic fragment dorsal to metatarsal head within joint effuion. With motion of phalanx on metatarsal head this fragment doesn’t move in relation to metatarsal head ie the phalanx moves away from it with plantarflexion and towards with dorsiflexion. I have annotated this region.

My thoughts are that it is most likely an osteochondral defect not seen on Xray, possibly calcification response to uric acid which you mentioned seeing on debridement, or less likely evidence of CPPD. Lack of fragment movement within joint space make this feature unlikely to be an avulsed marginal ostophyte or other floating fragment within joint.

Physical exam is negative for pain with palpation of plantar 2nd or 3rd metatarsal heads or resistance testing of intrinsic or extrinsic dorsiflexors/plantar flexors which show normal strength. There is no pain with application of C128 tuning fork to dorsal metatarsal shaft which I normaly use for evidence of possible stress fracture.

Patient is self medicating with diclofenec 50mgs TID for past week, pain has reduced somewhat but swelling /redness still obvious.

So far as far as I can see imaging and exam suggest synovitis but the underlying cause is not determined. This is why I feel arthrocentisis in this instant would be helpful if not essential in identifying cause of problem and I can’t see any other test which would give this information.

Any suggestions with reasoning welcomed.

Cheers

Martin

Attached Images

Knight Vince May-18-07 img3 anotated.jpg (61.6 KB, 216 views)

Hi Martin:
Looks like a small exostosis on the metahead with synovitis. Very common. As I mentioned previously, he may also have an OCD or merely degenerative arthritis from a biomechanic fault, injury, etc........ I think you're complicating this. NSAI's with some local therapy (US, Phono, ICE, Padding to reileve pressure, intraarticlular cortisone injection) should help. If there is a mechanical fault and his condition recurs then that will need to be addressed. If he has an articlular pathology that is not responding to conservative treatment then surgical debridement is indicated. If the metatarsal is pathologically long then a shortening osteotomy is in order. He may have a hypermobile first ray causing displacement of weight to the second. There may be early contraction of the 2nd MTPJ with secondary plantar flexion (or a combination)..etc.........
Bottoms up!
Steve

One more thought..........he may have the start of symptoms of a Freiberg's infarction.

Steve

Thanks for your further thoughts and I can appreciate your reasoning. I take your point regarding my overcomplicating the issue but still I am asking myself the question regarding importance of investigating possibility of crystal deposition disease (CCD) when there is reasonable suspicion for this, how this might affect treatment plan and outcome and hence the original point of this thread regarding arthrocentesis.

In this case my suspicion for CDD is based on; prior history of gout, evidence of acute synovitis from imaging, symptoms and physical exam. There has been modest response to oral diclofenec after one week. To my knowledge 2nd metatarso-phalangeal joint is not a common site for gout, but could have been triggered by trauma.

So what now? Treat as simply mechanical issue, or investigate possible complication of metabolic problem? Perhaps prescription for imdomethacin should take care inflammation from gout in short term and addition mechanical approach required if simply mechanical cause.

What has stimulated a renewed interest in this area for me is becoming reasonably proficient using high quality diagnostic ultrasound and being able to use it to get an instant answer to question “is this patient’s pain related to synovitis”.

What I am finding over the past several months is conformation of more monoarthritis of forefoot joints than I noticed before and I suspect this is simply because I can identify arthritis more confidently. It strikes me that in cases of suspicion of gout I should be able to able to determine this definitively.

I am not because I have not taken any training for arthrocentisis or associated microscopy, which appears a straightforward technique. Also because other healthcare professionals who I would normally refer on to do not seem to be following recommendations in the literature, ie blood chemistry in not reliable to rule out CDD.

So back to original inquiry regarding how others approach this situation and perhaps it would be pertinent to expand that discussion to include;

Do podiatrists have a role in performing this test?

What are the indications for performing arthrocentisis for foot arthritis?

If not trained in this can it be safely and reliably be self taught, or require some training?

Should there be an accreditation process to ensure reliability?

How to deal with the possibility that presence of microscopically identifyable crystals does not rule out concurrent infection; in other words where do the boundries of podiatry clinic and pathology lab become seperated?


Cheers



Martin

Anyone following this thread might be interested in following the case I used for clinical discussion.

I saw the gentleman again yesterday; essentially his presentation was unchanged except for slight reduction in pain.

Repeat diagnostic ultrasound exam showed increased joint effusion/synovitis of 2nd metatarso-phalangeal joint. I decided to aspirate the joint and removed approx 0.5ml fluid which was cloudy.

Examined with non polarized light microscopy I was able to detect needle shaped crystals which matched those I found of monosodium urate in synovial fluid samples illustrated in the literature. Discussion subsequently with pt’s new physician reported significantly raised serum uric acid from more recent blood workup and he will now take over this problem.

Over the past week I have done a fairly compressive review of literature specific to microscopy of synovial fluid and crystal deposition disease (CDD). If there is any interest if I get time I will attempt to consolidate and post a lit review as I see it.

A simplified impression which I have formed is that;

Arthrocentisis/microscopy is highly indicated with reasonable suspicion of CDD, this is not a difficult or time consuming procedure but rarely seems to be performed for the foot.

Use of a combination of polarized and normal light microscopy can easily identify and differentiate MSU from CPPD as cause of arthropathy.

I cannot see any reason (other than possibly need for accreditation of microscope examination technique/accuracy) that this could not be performed by podiatrists with basic training.

The literature shows concern regarding issue of lack of consistency between different observers and training therefore is important.

Although we do not treat gout or CPPD arthropathy, it must be on many a podiatrist’s differential diagnosis list on a regular basis.

Is this diagnostic procedure being taught presently as part of any podiatry curriculum around the globe?

If not is there good reason or is this simply oversight?

Cheers

Martin

Martin,

I perform arthrocentesis whenever a patient presents with gout-like signs/symptoms and has not previously been diagnosed with gout. It is a relatively fast, easy procedure.

First, for patient comfort I anesthetize the area. For a 1st MTPJ arthrocentesis, I perform a Mayo block to surround the first metatarsal.

I then grab the biggest syringe/needle I can find (our office buys 10cc/20ga syringes). The bigger the syringe, the better "pull" of joint fluid you'll get. Anything smaller than 10cc probably will fail.

I prep the skin with Betadine.

Once anesthetized, with one hand I forcefully distract the hallux and look for a puckering of the skin to reveal the joint space. Then with the other hand I insert the needle into the joint then withdraw fluid. Expect to get only a few drops at the most.

My view is that the Primary Care doctor is drawing blood for a uric acid because he or she is uncomfortable with aspirating a joint, not because it's a better test.

Nat

Hi Nat:
I have found that injecting a small amount of 1 or 2% xylocaine into the joint makes it easier to perform the arthrocentesis.
I normally just use a small (25 G) needle to raise a wheel just medial to the EHL then inject some of the xylocaine into the joint. I then use an 18 G needle on a 5cc syringe to aspirate. It should not be painful. The extra intraarticlular xylocaine helps increase the volume and pressure and makes it easier to aspirate.
I use this same method on ankle joints and ganglions.
Dr. Steve

If the patient is acute (red, hot, exquisitely tender), I prefer the proximal block rather than sticking a needle into an already painful area. They are less anxious about the procedure ("My joint kills and you want to stick a needle into it?!?!") and I find it gives them some degree of pain relief afterwards too.

Nat

Nat and Steve

who does your microscopy, how reliable to you consider the results and do you concurrently look for evidence of septic arthritis?

thanks

Martin

I send the specimen to the lab at the hospital and have them look at it. I don't also ask for bacterial culture or draw labs unless the history and physical somehow places infection in the differential Dx.

The lab has not given me any reason to doubt their reliability. If patients respond to NSAIDS and the exam reveals crystals, I feel confident in the Dx. and refer them to a Rheumatologist for medical management.

Nat

appears to be intraarticular joint fragment /loose body.There doesnt appear to be hyperechoic speckling with in the hypoechoic area of effusion that usually is seen when preforming dx ultrasound on gouty patients confirimed by athrocentesis. serum uric acid may be normal during acute episode .Have seen normal uric acid levels even when tophi evident on plain films Nerve block/vasodilation hyperermia effect followed by nsaid usually help. Referral to pcp for medical management 24 hour urine analysis determine overproducer .under secretor kidney stones one of the concern if improperly treated. orthotic shoe modification to decrease trauma to joint area.

Assuming you are refering to #5 image.

Agreed regarding lack of "speckling" or complex and inhomogenous hypoechoic appearance typical in suspected gouty joints. I am curious regarding your interpretation of loose body though; I mentioned in the description that the hyper echoic fragement did not move in relation to MTH with sagital motion of prox phalanx - how would you reconcile this apparent attatchement?


cheers

Martin

I t is approximately eighteen months since starting this thread.

During that time I have satisfied myself that I can competently perform ultrasound guided arthrocentesis, and using polarized light microscopy identify uric acid crystals from a single drop of synovial fluid extracted with a 27 gauge needle with minimal discomfort from suspect lesser toe metatarso-phalangeal joints.

I continue to discover undiagnosed gouty arthritis which is missed by others simply because typical symptoms are not present and/or serum uric acid is not elevated and gout has been regarded as unlikely by them.

I saw a good example this week and felt inclined add this post to encourage others to consider adding to their clinical skills testing to allow definitive approach. Some technical conciderations are added at end of post too.

brief case history;

Hx of complaint; 66 year old male, patient reports to be in good general health, history of right foot 2nd metatarsal head AVN 10 years ago, no intervention uneventful for problems until 6 weeks ago, he stepped awkwardly, pain developed following day, with swelling erythema, weight-bearing pain, no rest pain or bruising.

Patient reported initially seeing primary care physician subsequent to radiographic exam being told that it showed no significant findings. Pt was put on oral abiotics because suspicion of cellulitis. Symptoms were non responsive, had athrocentesis attempted at outpatient care to rule out infective arthritis, aborted because” unable to get fluid” was put on parental antibiotics for four days, unresponsive. patient reported that extensive blood work up results –ve for evidence of gout or infection. He was then referred to orthopedic surgeon, no diagnosis explained to patient and but put in total contact cast for seven days then BKW for two weeks, reduction in pain but not swelling. He was then advised to return to normal foot-wear and prescribed naproxen and appt to review progress after three months.

I saw him last week. Patient reported slight worsening of symptoms from onset was limping badly.

Diagnostic ultrasound exam showed severe acute synovitis of 2nd metatarso-phalangeal joint. I did ultrasound guided arthrocentesis which was unequivocal for gout. Since then after 5 days of indomethacin he is almost pain free. Recent blood workup showed slightly elevated serum uric acid and was prescribed allupurinol too.

Lessons are;

literature unequivocal for needing arthrocentesis vs serum uric acid for definitive diagnosis, apart from my own testing I have never seen a patient who has had this done for foot joints.

So why is this?

I can only assume that health care providers are not aware of diagnostic criteria, or are unable/uncomfortable to perform arthrocentesis in foot joints.

There is in my experience a problem doing arthrocentesis on small joints.

They do not contain much fluid, so needle placement needs to be very accurate, this is very hard with a swollen foot because joint outline is obscured and site may be very tender to palpate.

All that is needed is a single drop but the slide needs immediate preparation because fluid will either dry or if containing platelets clot and be useless. If this drop is diluted in anticoagulant fluid the density of crystals or solubility may be sufficient to ruin sample.

This is why I feel that this is best done right in the office.

Ultrasound guidance take the guess work out of location of the fluid and in this instance I think allows obtaining sample straightforward vs difficult and potentially uncomfortable.

The skills can be self taught ( I simply created my own samples using slightly saturated solution of reagent uric acid, and self review of good microscope setup and technique which is really important), better still should be added to undergrad curriculum and supervised and tested.

The critical and essential study is synovial fluid analysis to identify urate crystals.

Finding intracellular urate crystals with polarizing light microscopy firmly establishes the diagnosis of gouty arthritis.

Urate crystals are shaped like needles or toothpicks with pointed ends.

Urate crystals are negatively birefringent, meaning that the crystals are yellow when aligned parallel to the slow ray of the compensator and that they are blue when they are perpendicular.

Pseudogout crystals (calcium pyrophosphate) are rod-shaped with blunt ends.

Pseudogout crystals are positively birefringent.

Pragmatically, this means that their colors are opposite those of gout.

Thus, pseudogout crystals are blue when aligned parallel to the slow ray of the compensator and yellow when they are perpendicular.


good demo of PL microscopy @

http://www.olympusmicro.com/primer/j...ion/index.html

Crystals need to be distinguished from birefringent cartilaginous or other debris.

Debris may have fuzzy borders and may be curved, whereas crystals have sharp borders and are straight.

Images below to illustrate some important features of this case.


appearance.JPG

without power dopper it is clear that the synovial envelope is grossly abnormal


US no PDI.jpg

adding PDI shows clearly extensive motion within synovium which is caused by RBCs within proliferatively neovascularised synovial tissue.

US with PDI.jpg

examination of drop of synovial fluid (contaminated with blood from synovial tissue). with no polarisation it is difficult/ impossible to see crystals especially with the RBCs complicating image.

1.jpg

note how large cluster of crystals becomes quite obvious once polarised light axes are aligned perpendicularly. in second image.


2.jpg

these images are 100X. Unfortunately my digital microscope camera has very lossy definition, couple that with compression of images to enable upload, the quality is severly reduced from what is actually seen in the microscope. However the features are intelligable.

I will post continuation because I have maxed out this post for uploads.


hope this informative

cheers

Martin


The St. James Foot Clinic
1749 Portage Ave.
Winnipeg
Manitoba
R3J 0E6
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

Hi Martin:

Thanks so much for taking the time to upload these images and share them.
You're quite diligent.

Question:

Have you attempted to dilute then aspirate a gouty joint therapeutically?

Thanks again

Steve

__________________
DrSArbes
Fellow American College of Foot & Ankle Surgeons
Board Certified Foot & Ankle Surgery, ABPS
Green Bay, Wisconsin, USA

Hi Steve

No I have not tried this.

I wonder how effective this would be since I suspect much of the pain problem may be associated with the synovial proliferation and likley not readily irrigated.

Anyone try this, what results?

cheers

Martin

Here is rest of microscopy series


400X no PL

4.jpg


400X with 45 degree axis PL

5.jpg


400X 90 degrees axis PL


6.jpg


where's Nemo?

7.jpg



all over the place


8.jpg



cheers

Martin

The St. James Foot Clinic
1749 Portage Ave.
Winnipeg
Manitoba
R3J 0E6
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

Hi Martin:
Again, just really nice slides.
You may talk me into purchasing a microscope!

Re: flushing.....I've injected a few ankles over the years with plain xylocaine then aspirated / back and forth with no real quantitative value in mind other than feeling that I've flushed it out well. My last injection is always Marcaine. It seems to help, of course no way to really know if I'm just anesthetizing the area for a day or really decreasing the pain due to crystal removal.

Thanks again

Steve

__________________
DrSArbes
Fellow American College of Foot & Ankle Surgeons
Board Certified Foot & Ankle Surgery, ABPS
Green Bay, Wisconsin, USA

Hi Steve

The patients I have examined (both +ve and -ve for evidence with microscopy) are very pleased to get this done, particularly if, like this patient, they have eluded prior diagnosis and really suffered uneccessarily.

I use an inexpensive Olympus CH1 binocular microscope ($400 used from ebay) and retrofitted it with polarising filters ($100 from microscopesindia.com) which is more than adequate for this task.

The key for me establishing reliable technique was using some reagent to familiarise myself with microscopic appearance of crystals, and carefully refreshing knowledge of how to optimise set up of microscope. I had advantage in prior brief career as biochemist learning importance of optimising focus and aperture of condenser, this is vital since this needs fine tuning to optimise detection.

The example I used here was easy because the sample was heavily loaded with crystals. I have seen others where it was neccessary to scan the entire field carefully at 100X to locate crystals before using 400X to carefully identify morphology.

I think I already outlined the major pitfalls of misinterpretation.

Perhaps we are not taught this at undergrad level because the small joints would be tricky without US, however an ankle doesnt really need guidance so there must be some other reason.

This is a basic useful test which seems neglected by all health care providers where I practice and I suspect generally.

Perhaps it should be taught . . . any course curriculum planners care to comment?

Like you, I top up with marcaine just to give some temporary relief before Imdomethacin kicks in.

cheers

Martin


The St. James Foot Clinic
1749 Portage Ave.
Winnipeg
Manitoba
R3J 0E6
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

Hi Martin:
Thanks again.

On a practical level, how long does it take you from aspiration to microscope examination?

Steve

__________________
DrSArbes
Fellow American College of Foot & Ankle Surgeons
Board Certified Foot & Ankle Surgery, ABPS
Green Bay, Wisconsin, USA

Anyone interested in published reference for sonograhic imaging of crystal deposition disease check out this fabulous book.

Musculoskeletal Sonography 1.pdf


Interesting description used of“urate sand” almost poetic, nicely descriptive, I wish I had coined this!

I have attatched a couple of pertinent pages to give a taste of the quality of this book, if you have any interest in MSK US go order it

Musculoskeletal Sonography 177.pdf

cheers

Martin

The St. James Foot Clinic
1749 Portage Ave.
Winnipeg
Manitoba
R3J 0E6
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

Hi Steve
I noticed that my reply form yesterday seems to have not posted - hope I did n to inadvertently sent it to wrong thread!
Time taken depends entirely on presence and density of crystals. The example I posted with images took less than 1 minute simple because of high density of crystals.
I will spend perhaps 3 or 4 minutes carefully scanning a slide at 100x when there are no or very few crystals. If there is debris which creates birefringence it needs examining for morphology and this will add a bit of time to change and refocus objective to 400x and optimize image with diaphragm and filters.
I keep a digital image of anything of interest which I make available to primary care physician.
On average I would say I spend around 15 minutes to examine slide, store and label digital image and create report. For entire exam including Diagnostic ultrasound exam and joint aspiration and microscopy I allow 30 minutes, since this is usually mono articular this would be per joint.
If you decide to give this a try and need further advice I’d be glad to see if I can help.
Cheers

Martin

The St. James Foot Clinic
1749 Portage Ave.
Winnipeg
Manitoba
R3J 0E6
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

1: Ann Rheum Dis. 2008 Feb;67(2):273-5. Epub 2007 Jun 8. Links
First metatarsophalangeal joint aspiration using a 29-gauge needle.Sivera F, Aragon R, Pascual E.
Rheumatology Unit, Hospital General Universitario de Alicante, Universidad Miguel Hernándes, Spain.

OBJECTIVES: To asses the clinical feasibility of aspirating symptomatic and asymptomatic first metatarsophalangeal (MTP) joints with a 29-gauge needle in order to obtain a synovial fluid (SF) sample. METHODS: All consecutive aspirations of first MTP joints performed within our department were prospectively recorded. The procedure was considered successful if SF volume was enough to perform a crystal search. Crystals were identified using a polarised light microscope (magnification x400) with a first order red compensator. Pain was recorded on a 10-cm visual analogue scale (VAS). RESULTS: Aspirations were attempted in 33 first MTP joints in 31 patients. SF was drawn from 30 of the joints (91%), with little difference between asymptomatic (89%) and inflamed joints (93%). The technique was well tolerated (mean VAS 1.74). Urate monosodium crystals were identified in 22 samples (73%) and another sample contained calcium pyrophosphate dihydrate crystals. CONCLUSIONS: A 29-gauge needle allows easy aspiration of the first MTP joint with only modest discomfort for the patients, and generally yields a SF sample of sufficient volume for crystal detection and identification.

example of polarised light Ca pyrophosphate crystal

Attached Images

Ca pyrophosphate image.jpg (18.5 KB, 10 views)