Closed synovial biopsy of the various joints has been one of the diagnostic techniques in difficult rheumatological cases. Patients with synovitis of undetermined etiology may require tissue evaluation for diagnosis. Recent reviews have reinforced the opinion that it is not helpful in distinguishing amongst the common inflammatory arthritic disorders. However, the finding of lymphoid follicles in the synovium still appears to be restricted to rheumatoid arthritis.
The particular value of synovial biopsy remains in the diagnosis of the rare conditions such as hemochromatosis, ochronosis, cocidioidmycosis, tuberculosis synovitis, and amyloidosis. Other diagnostic possibilities are polarized light microscopic identification of various crystals like monosodium urate and calcium pyrophosphate. Rare disorders such as Whipple's disease and multicentric reticulohistiocytosis can also be identified. The need for careful tissue fixation, eg, absolute alcohol for gouty and calium pyrophosphate deposits and special stain (example: congo red for amyloidosis), is evident. Ultra structural electron microscopic analysis may be helpful in some diseases like Whipple's disease.
There are several reports of different types of needles and techniques for synovial biopsy. There has been difficulty with the popular Parker-Pearson needle, with the tip of the needle breaking within the joint capsule. This has necessiated open procedures or arthroscopic removal of the foregin body.
Advent of New Needle
With the advent of the new Tru-Cut needle, which has been used in the past several years by nephrologists for closed renal biopsy, needles have become more sophisticated and easier to use. This needle has even replaced the traditional Mengini needle for biopsy fo the liver. I have personally used a Tru-Cut needle for synovial biopsies in two cases in the past several months with successful results. This is a disposable needle of very small cost. It comes in 4- and 6-inch lengths. A 4-inch needle should be adequate.
Biopsy procedure, as usualy, must be performed using appropriate aseptic techniques. It is important (as when using a Parker-Pearson needle) to cut a 3 mm incision with a scalepl in and through the skin. Sterile normal saline can be injected inot the joint in order to exapnd the joint capsul. After removing the protective sleeve from the needle assembly, one has to check for proper function and alignment of the sliding and the cannula (outer hollow needle).
The Biopsy Technique
For usual biopsy procedures, the ensuing technique may be followed:
- Prepare the skin. For percutaneous procedures, assure adequate anesthesia.
- Incise the skin with a scalpel.
- With the obturator fully retracted to cover the specimen notch, hold cannula hub and insert the needle assembly so that the specimen notch is within the tissue to be biopsied.
- Without moving the obturator, retract the cannula to expose the specimen notch by pulling outward on the larger T-shaped cannula handle.
- To cut the tissue which has prolapsed into the specimen notch, quickly advance the T-shaped cannula handle.
- Withdraw the needle assembly with the cannula still advanced over the obturator.
- Advance the obturatory to remove biopsy specimen from the specimen notch
Post biopsy patient care is as usual, and within a couple of hours the patient can be weight bearing. This simplified technique and equipment will allow more diagnostic synovial biopsy to be performed in the future.
(Orthopaedic Review 1982; 11:139-140)
