Several people on the list have talked about decalcification techniques in 
clinical practice. Let me contribute experience of a small-laboratory 
surgical pathologist laboring in his last years of practice under Managed 
Care. In these circumstances we cannot hope for new technology, but we can 
sometimes salvage old technology. In many of the small laboratories I work 
in, decalcification skills are being lost.

As to turnaround time: I wish I knew what TAT large orthopedic specimens 
(mostly hips and knees) require. If they need a surgical pathology report for 
billing purposes, they need it in a bit less than a week. 

If I receive a femoral head on Monday, I can slab it, fix the slabs 
overnight, and decalcify a piece of a slab over another night - that means I 
have slides Thursday morning. To take a day off of this, somebody has to move 
the specimen from fixative to decalcifying solution late at night.

The elegant radiographic technique one of you described would be nice to 
have, but I've seen an in-department radiographic unit (Faxitron) in exactly 
one of perhaps forty surgical pathology labs I've worked in since residency. 
If I had this technique, I'd use it, though I suspect its yield of clincally 
useful information would be small. My normal special tools for slabbing heavy 
bone are a dime-store hacksaw and a wad of paper towels - a Satterlee saw 
(from Lipshaw) is usually many managers away.

For clinical purposes, gross diagnosis is often adequate for joint 
replacement specimens done for osteoarthritis. The description and gross 
diagnosis are simple once you know what to look for. The high school dropouts 
who decide whether or not surgeons get paid are programmed to recognize the 
following string: "eburnation and osteophyte formation consistent with end 
stage osteoarthritis", and those exact words should appear in the diagnosis 
line. 

Osteophytes are the mounds of cartilage and distorted bone that appear at the 
edges of articular surfaces. Eburnation is the baring of bone (the word 
originally meant "turning into ivory") by the erosive process. The point of a 
knife will not enter an eburnated surface, as it will even the thinnest of 
abraded articular cartilage. Eburnated surfaces are usually oval and often 
grooved.

I would describe such a specimen as "Received in formalin is 120 grams of 
products of a total knee replacement, including an intact tibial plateau, 
fragments of femoral condyles, loose osteophytes, menisci, and fatty 
synovium. The condylar fragments show oval areas of grooved eburnated bare 
bone as much as 30 mm wide, and smaller eburnated foci are present on the 
tibial surface also. Osteophytes up to 10 mm wide surround the articular 
surfaces. No sections are submitted." (Victoria Ryder, is this the question 
you wanted an answer to?)

If the laboratory's ritual requires decalcified sections, I painfully slab 
out sections of eburnated bone. Real men use an oscillating (Stryker) saw for 
this purpose, but this technique is thoroughly unsafe, and would not be 
permitted if people anybody gave a damn about were doing the gross 
examination.

Fractured femoral heads need microscopic examination, because metastatic 
cancer occasionally causes fractures ("pathologic fractures") and needs to be 
identified. (Remember that the pathologist is working without the patient's 
history.) Usually the osteoporotic bone is easy to slab with a hacksaw, 
though some of them indeed are hand-hurters. If the service is well enough 
managed that the pathologist or assistant is working entirely without the 
patient's history, the 10 mm wide hemorrhagic fracture zone in the otherwise 
dull yellow cancellous bone identifies a recent fracture.

Obviously I'm describing clinical techniques, not research. I prefer to do my 
own decalcification, though many pathologists prefer to hand it to the 
technologist. The important thing is to decide who's going to do it, so that 
the decalcifying specimen doesn't go astray - and pathologists are notorious 
for mislaying them.

Arthroscopic specimens need microscopic examination, though many pathologists 
are required to gross-only these specimens. The diagnostic yield on 
arthroscopic specimens is quite high, even though in a well run hospital it 
is impossible for the pathologist to obtain clinical history or arthroscopic 
findings. It's usually acceptable to avoid gross bone fragments in selecting 
arthroscopic tissue for microscopic examination.

Gayle Callis mentions "For articular cartilage in osteoarthritic knees, 
safranin O/Fast Green is commonly used, and toludine blue may also be 
useful." The safranin O trichrome variant - basically it's in Lillie's 3rd 
ed. - would be nice to have for arthroscopic material, but I have never seen 
it. Gayle, are the complex techniques you describe designed for routine 
clinical use, or for research purposes?

Bob Richmond
Samurai Pathologist
Knoxville TN