Routine Pathological Examination of Operative Specimens from Primary Total Hip and Total Knee Replacement: Another Look

This issue of The Journal contains two important articles related to the topic of routine pathological examination of operative specimens from patients undergoing total hip or total knee arthroplasty for the treatment of osteoarthritis. As pointed out in the article by Kocher et al., many surgeons believe that routine pathological examination of specimens removed at surgery is mandatory4. However, regulations by the Joint Commission on Accreditation of Healthcare Organizations note that the clinical staff, in consultation with the pathologist, may make an exception to mandatory submission of tissue when certain conditions are met3. These conditions include (1) the quality of care is not compromised by the exemption, (2) another suitable means of verification of removal has been used, and (3) there is an authenticated operative note or other official report that documents tissue removal.

Kocher et al. analyzed a total of 1234 specimens removed at the time of total hip or total knee arthroplasty for the treatment of osteoarthritis4. In each case, the preoperative clinical diagnosis was compared with the final pathological diagnosis obtained after histological evaluation of the resected tissue. The authors used three categories for their comparison: (1) concordant (agreement between the clinical and pathological diagnoses), (2) discrepant (a difference between the clinical and pathological diagnosis but no alteration in patient management), and (3) discordant (a difference between the clinical and pathological diagnoses resulting in alteration of patient management).

The authors found a concordance rate of 97.6 percent. There was a 2.3 percent rate of discrepant diagnoses, which included rheumatoid arthritis, osteonecrosis, pseudogout, pigmented villonodular synovitis, hemochromatosis, hypercellular bone marrow, and gout. The cost to the laboratory per discrepant diagnosis was $4383. Apparently the care of these patients, including those with unexpected osteonecrosis of the femoral head, was not altered by the histological diagnosis. Only one discordant diagnosis (0.1 percent), a case of unexpected and unexplained granulomatous inflammation, was identified. The calculated cost per discordant diagnosis was $122,728. The authors concluded that routine pathological (histological) examination of surgical specimens obtained at primary total hip or total knee arthroplasty may not be justified for patients with the preoperative diagnosis of osteoarthritis since the prevalence of findings that altered patient management in their hospital was so low. On the other hand, they recommended routine histological evaluation of specimens from patients with the preoperative diagnosis of osteonecrosis or inflammatory arthritis.

In a related article, Billings et al. reported the recognition of sarcoma in two routinely evaluated specimens that had been retrieved during primary total hip arthroplasty1. One of the two patients had undergone radiation and chemotherapy for cervical carcinoma. The other patient reported increasing pain and disability associated with Paget disease. Billings et al. emphasized the importance of routine pathological examination of femoral head specimens retrieved during total hip arthroplasty, especially when a patient is at risk for the development of a secondary malignant tumor.

Critical to the calculations described by Kocher et al.4 are the absence of rare diseases in their cohort of 1234 cases and the values used for cost calculation. The routine histological evaluation of specimens obtained at primary arthroplasty in patients with osteoarthritis by one of us (T. B.) yielded rare cases of Paget disease, infection, enchondroma, Gaucher disease, multicentric reticulohistiocytosis, lymphoproliferative disorders, metabolic bone disease (including osteomalacia), crystalline arthropathies, oxalosis, and inflammatory arthropathies other than rheumatoid arthritis. Some of these systemic disorders had been recognized preoperatively, but documention of involvement of the femoral head influenced the care of some patients. Although these cases are rare, some of the diagnoses were important to the individual patients involved.

There are several ways to improve the cost efficiency of tissue evaluation. One way is to reduce the proportion of specimens submitted to the pathology laboratory when a discordant diagnosis is unlikely; another is for the pathology laboratory to reduce costs (and presumably charges). Interestingly, in the series reported by Kocher et al., overall laboratory costs exceeded reimbursement4. It should be noted, however, that the costs, charges, and reimbursement values used in the calculations by Kocher et al. might be unique to their hospital environment. The values quoted for charges, for example, are nearly twice the fees charged at the Cleveland Clinic for similar tests. In order to reduce costs, Kocher et al. recommend not routinely submitting tissue obtained at primary total joint arthroplasty for the treatment of osteoarthritis. However, there may be other options that could limit the potential harm of missing important diagnoses. One such option is to routinely send such tissue to the pathology laboratory but for the pathologist to submit tissue for histological examination only if requested by the surgeon or if gross evaluation of the tissue suggests an unexpected finding. This gives the pathologist the opportunity to look at the synovial tissue and to inspect the cut surface of the femoral head for evidence of osteonecrosis or other abnormality. A charge for a gross diagnosis is made, but it should be substantially less than that for histological evaluation. If gross evaluation reveals an unexpected finding, then representative tissue can be submitted for histological evaluation. It also seems appropriate to perform routine histological evaluation of specimens from patients with osteonecrosis, inflammatory arthropathies, or femoral neck fracture and of specimens obtained at revision arthroplasty.

While reducing costs is an important concern, one should be mindful that the histological study of resected tissue serves many purposes in addition to immediate patient care. As noted by Kocher et al., histological diagnoses also facilitate diagnostic quality assurance and provide insight into the pathogenesis and natural history of disease4. In a previous, related editorial in The Journal, Bullough and Dorfman pointed out that examination of tissue by a trained independent physician is the gold standard of quality assurance2. Furthermore, much of our current understanding about degenerative joint disease, osteonecrosis, and inflammatory arthropathies has been derived from careful but routine evaluation of specimens obtained during total joint replacement. They cautioned that such specimens should not be discarded in a cursory manner2. The value of this process to research and education should not be overlooked. Nevertheless, the take-home message for the practicing orthopaedic surgeon is that the routine histological evaluation of tissue excised from patients with an uncomplicated case of osteoarthritis may not be necessary at all hospitals. On the other hand, when a patient has another disorder that might complicate osteoarthritis, when careful gross examination of synovial tissue or a sectioned femoral head suggests an unexpected finding, or when the results of such analysis are used for ongoing quality-assurance studies, histological examination is warranted.