bone biopsy ?

[malleolusman]

if u were trying to distinguish between charcot foot or osteomyelitis (where bone is not exposed)

if that patient is diabetic & has poor wound healing & vascular issues, i guess a bone biopsy is out of the question--

what options are available to make a reliable diagnoses?

---

Members don't see this ad.

 

[Feli]

You can do a core cut needle bone biopsy with a 5-10mm incision and about 15min of OR time... wouldn't say it's ever "out of the question."

You can do a labeled nuclear med scan if you really think surgery is contra-indicated, but a good clinical history is probably your best diagnosis in the majority of cases:
Does the patient have a history of prior osteomyelitis, hardware, or open chronic wounds near the area of XR changes?
Is there new fragmentation at a high motion joint (ankle/STJ/midtarsal) with no prior history of wound/surgery nearby?
Has he been a neuropathic diabetic for years with poor control and Charcot of either foot in the past? Alk phos?
Are there any constitutional symptoms? Antibiotic failure? WBC or left shift? ESR? Fever, tach, etc?

 

[krabmas]

if u were trying to distinguish between charcot foot or osteomyelitis (where bone is not exposed)

if that patient is diabetic & has poor wound healing & vascular issues, i guess a bone biopsy is out of the question--

what options are available to make a reliable diagnoses?

I agree with feli.

and what exactly do you mean by poor wound healing? vascular issues?

it is arguable that all diabetics have poor wound healing compared to a normoglycemic person, and those with an elevated HbA1c have even more wound healing problems, and then those with ABIs <0.8, and low PPM/TcPO2 have even more wound healing problems.

Typically charcot patients have bounding pulses, but occasionally you do run into the calcified vessels and poor vascular perfusion with charcot.

Can you give some more info into your clinical question? Is there an ulcer? what is the HbA1c? What are the ABIs, TBIs, TcPO2...? Has the patient had an angiogram?

 

[malleolusman]

I agree with feli.

and what exactly do you mean by poor wound healing? vascular issues?

it is arguable that all diabetics have poor wound healing compared to a normoglycemic person, and those with an elevated HbA1c have even more wound healing problems, and then those with ABIs <0.8, and low PPM/TcPO2 have even more wound healing problems.

Typically charcot patients have bounding pulses, but occasionally you do run into the calcified vessels and poor vascular perfusion with charcot.

Can you give some more info into your clinical question? Is there an ulcer? what is the HbA1c? What are the ABIs, TBIs, TcPO2...? Has the patient had an angiogram?

No specific case,- my question was stemming from a lecture we had on OM and how one of the differentials is charcot. I just figured a bone biopsy might be contraindicated if you knew the patient had poor wound healing, poor/no pulse, high HbA1c.

Thanks for the thorough responses

 

[diabeticfootdr]

No specific case,- my question was stemming from a lecture we had on OM and how one of the differentials is charcot. I just figured a bone biopsy might be contraindicated if you knew the patient had poor wound healing, poor/no pulse, high HbA1c.

Thanks for the thorough responses

If there is no break in the dermal envelope (ulcer) or history of such, the likelihood of OM is extremely low and can almost be ruled out on clinical grounds.

The most complex cases have an ulcer and radiographic changes in the bone near the ulcer. In these cases it can be Charcot, OM, or both. MRI is not a good tool to distinguish Charcot from OM. If you are using an MRI, you need to consider "secondary signs". 1. OM usually affects only 1 bone, Charcot a joint or several joints. 2. OM usually affects the forefoot or calcaneus, Charcot the midfoot or ankle. 3. OM usually has a visible tract on MRI from the skin to the bone.

Another good way to determine Charcot from OM, is by using combination bone scans. Tech99 and In111 or Ceretec. Tech99 and Ceretec can't be done on the same day, but Ceretec is a better WBC scan than In111.

We have been using PET scan as a single test to differentiate Charcot from OM. There are a few articles on this from Germany. So far, we've found the SUV is able to differentiate based on uptake.

I wrote an article on this topic which we review all the imaging tests and their sensitivities/specificities for Charcot: Imaging of the Charcot Foot. Clin Podiatr Med Surg 2008;25:263-274

Bone biopsy is fine, but can get contaminated, and should be done under fluoro.

In summary, it is a combination of clinical exam and imaging tests that provide the most accurate results.