Histopathology of femoral head donations: a retrospective review of 6161 cases

Routine Histopathologic Examination of Bone Obtained During Elective Primary Total Knee Arthroplasty May Not Be Necessary

Background

Many institutions require the routine collection of pathology samples from every primary total knee arthroplasty (TKA) performed. These policies are controversial, and their cost-effectiveness is difficult to define. We sought to judge the cost-effectiveness of one such policy according to World Health Organization recommendations.

Methods

We analyzed 3200 consecutive primary TKAs, comparing our presumed preoperative diagnoses against the diagnoses made by the pathologist. Diagnoses were categorized as concordant (matching), discrepant (not matching but without impact to patient management), or discordant (not matching and resulting in a direct change to patient management). An incremental cost-utility ratio analysis was performed to determine the cost-effectiveness of our institution's policy to routinely collect pathology samples from every primary TKA performed. Cost-effectiveness was defined by World Health Organization guidelines as a cost of less than $228,090 per quality-adjusted life year gained.

Results

Twelve pathology samples were lost before reaching a pathologist. From the remaining 3188 samples, we identified 3158 concordant cases, 29 discrepant diagnoses, and 1 discordant diagnosis. It cost an estimated $10,522.60 to identify each discrepant diagnosis and an estimated $305,155.36 to diagnose one discordant case in our cohort. Our incremental cost-utility ratio analysis revealed that we spent $305,155.36 to gain 0 quality-adjusted life years for our patients.

Conclusions

Routine histopathologic analysis of TKA samples was cost-ineffective in our patient cohort and may not be necessary during routine TKA.

Routine Histopathologic Analysis of Hip and Knee Bone Specimens After Total Joint Arthroplasty

Total hip and total knee arthroplasties (THA/TKA) are some of the most common elective surgeries done in the United States. Routine histopathologic analysis of hip and knee bone specimens after total joint arthroplasty commonly occurs to identify unexpected pathologic findings and serves as a quality assurance measure. As the most common indication for THA and TKA is osteoarthritis, the practice of routine histopathologic analysis may not be routinely warranted. There is no clear consensus on the cost-effectiveness of this practice, and the literature has questioned both the clinical relevance of discrepancies between surgeon diagnosis and histopathological diagnosis and raised concerns about variance in the histological evaluation of resected specimens by pathologists. Femoral head analysis in the setting of femoral neck fractures has been previously reported, yet there is no clear overview for this topic in the setting of elective THA. The histopathologic features of bone specimens during routine total joint arthroplasty, the cost-effectiveness, and current recommendations will be reviewed.

Selective pathological examination following hip arthroplasty: A retrospective cohort study

BACKGROUND

Pathological examination of the femoral head after hip arthroplasty is often performed routinely. The cost-effectiveness of the examination with regard to identifying clinically relevant diagnoses has been a point of discussion. To date, recommendations on performing pathological examination based on patient characteristics, disease history or radiographic findings are scarce. The aim of this study was to gain insight in when to select a patient for pathological examination of the femoral head by means of the following research questions: "How many clinically relevant diagnoses does selective pathological examination identify?" "Which factors contribute to selection of the femoral head for conducting pathological examination?" "What are the costs of selective pathological examination for identifying clinically relevant diagnoses?"

HYPOTHESIS

Selective pathological examination of the femoral head results in higher ratios of identified clinically relevant diagnoses against substantially lower costs.

METHODS

A retrospective cohort study was performed over the period of 2010-2015. All pathological reports were collected from our hospital and screened for resected femoral heads after primary total hip arthroplasty (THA) or primary hemiarthroplasty (HA). The coherence between preoperative diagnosis and postoperative pathological diagnosis was defined as concordant, discrepant or discordant. The aim was to perform logistic regression analysis.

RESULTS

In total, 164 patients were included of 3998 hip arthroplasties performed during the study period with a mean age of 74±12.3 years including 54 (33%) male and 110 (67%) female of whom 112 (68%) underwent THA and 52 (32%) HA. A discrepancy in diagnosis was found in nine patients (6%) and discordance in three patients (2%). The most frequently reported reasons to perform pathological examination were malignancy in medical history n=86 (53%), avascular necrosis n=22 (13%), bone abnormality perioperatively n=19 (11%) and pathological fracture n=13 (8%). The factors that identified the unexpected clinically relevant diagnoses were pathological fracture (3 cases out of 13), bone abnormality perioperatively (2 out of 19), abnormalities on preoperative radiographs (1 out of 9) and to a lesser extent malignancy in history (2 out of 86). With costs of pathological examination of approximately €163 per femoral head, performed in 164 patients, the total costs of pathological examination resulted in €26,732. The cost per discrepant case (n=9) was €2970 and the cost per discordant case (n=3) was €8910.

CONCLUSION

Selective pathological examination of the femoral head following hip arthroplasty results in higher ratios of discrepant and discordant cases against substantially lower costs. Factors that identify clinically relevant diagnoses are pathological fracture, perioperative bone abnormality, abnormalities on preoperative radiographs and to a lesser extent malignancy in history.

LEVEL OF EVIDENCE

III; retrospective cohort study.

Evaluation of the Cost Effectiveness of Routine Histopathologic Femoral Head Analysis in Hip Arthroplasty

Purpose

Histopathologic analysis of femoral head specimens following total hip arthroplasty (THA) is a routine practice that represents a significant use of health care resources. However, it occasionally results in discovery of undiagnosed hematopoietic malignancy and other discrepant diagnoses such as avascular necrosis. The purpose of this study was to determine the rate of discordant and discrepant diagnoses discovered from routine histopathological evaluation of femoral heads following THA and perform a cost analysis of this practice.

Materials and Methods

A review of patients undergoing primary THA between 2004-2017 was conducted. A comparison of the surgeon’s preoperative and postoperative diagnosis, and the histopathologic diagnosis was performed. In cases where the clinical and histopathology differed, a review determined whether this resulted in a change in clinical management. Medicare reimbursement and previously published cost data corrected for inflation were utilized for cost calculations.

Results

A review of 2,134 procedures was performed. The pathologic diagnosis matched the postoperative diagnosis in 96.0% of cases. Eighty-three cases (4.0%) had a discrepant diagnosis where treatment was not substantially altered. There was one case of discordant diagnosis where lymphoma was diagnosed and subsequently treated. The cost per discrepant diagnosis was $141,880 and per discordant diagnosis was $1,669 when using 100% Medicare reimbursement and Current Procedural Terminology (CPT) code combination 88304+88311.

Conclusion

Histopathologic analysis of femoral head specimens in THAs showed an association with high costs given the rarity of discordant diagnoses. Routine use of the practice should be at the discretion of individual hospitals with consideration for cost and utility thresholds.

Unexpected Primary Extranodal Marginal Zone Lymphoma of Bone in Amputation and Arthroplasty Specimens

OBJECTIVES

Amputation due to gangrene and arthroplasty for degenerative joint disease are common orthopedic procedures and are expected to increase as populations age. Histopathologic examination of these specimens can identify unsuspected diseases.

METHODS

We reviewed gangrenous amputations and large joint arthroplasty specimens for diagnosis of unexpected lymphoma, January 2014 to January 2020. Pathology and medical records were reviewed to determine diagnosis, treatment, and outcome.

RESULTS

Five cases (0.08%) of unexpected primary extranodal marginal zone lymphoma (MZL) centered in bone were identified in 1,624 amputations for gangrene and 4,163 arthroplasty specimens. The female-to-male distribution was 3:2. Median age was 71 years (range, 62-87). The 3 cases arising in the setting of gangrene involved the first toe phalanges and metatarsals, and the femoral head was involved in all cases of joint disease (2 cases). The bone showed variable (10%-80%) infiltration by dense populations of small lymphoid cells with MZL immunophenotype. One patient died from sepsis 18.5 months after diagnosis; all others are alive with a median follow-up of 27.45 months.

CONCLUSIONS

Histopathologic examination of nonneoplastic orthopedic specimens identifies unexpected primary bone extranodal MZL in a small percentage of cases. This neoplasm may be the result of chronic antigenic stimulation in some circumstances.

Pathology Assessment of Femoral Head Resection Specimens: An Important Quality Assurance Procedure

CONTEXT.—

Decisions to perform hip arthroplasty rely on both radiographic and clinical findings. Radiologists estimate degree of osteoarthritis (OA) and document other findings. Arthroplasty specimens are sometimes evaluated by pathology.

OBJECTIVE.—

To determine the frequency of pathologic changes not recognized clinically.

DESIGN.—

Nine hundred fifty-three consecutive femoral head resections performed between January 2015 and June 2018, with recent radiologic and histologic study, were reviewed. We compared severity of OA reported by radiology and pathology. Findings unrecognized radiographically but recorded pathologically, and discrepancies between clinical diagnosis and pathology diagnosis, were tabulated.

RESULTS.—

Twenty-one cases of osteomyelitis were diagnosed radiographically or pathologically. Eight discrepancies were present. Fourteen osteomyelitis cases were recognized clinically. Pathology recognized 2 neoplasms missed radiographically. Avascular necrosis was diagnosed on pathology but not radiology in 25 cases, and 35 cases of avascular necrosis were seen radiographically but not pathologically. Osteoarthritis was graded both radiographically and pathologically from 0 to 3. Five hundred ninety-one of 953 cases (62%) were grade 3. Pathologists and radiologists had perfect agreement in 696 of 953 cases (73%). When grade of OA seen at pathology was correlated with surgeon, 2 groups of surgeons were detected: one with a low threshold for performance of hip arthroplasty (23%-28% low-severity OA) and the second with a high threshold (2%-5% low-severity OA).

CONCLUSIONS.—

Correlation between radiology and pathology diagnoses is high. Degree of OA present varies significantly between surgeons. Pathology discloses findings not recognized clinically.

Neck of femur fracture: Previous history of malignancy is not an indication to send femoral head for routine histology

BACKGROUND

Neck of femur fractures is the most common fractures associated with low-velocity injury in the elderly. Some patients may require further histological examination of the femoral head due clinical suspicion of malignance as a cause of fracture.

OBJECTIVES

To review whether standard screening question(s) could be used to identify patients that require histological examinations following neck of femur fracture.

STUDY DESIGN AND METHODS

Femoral heads sent for histological examination over a period of 5 years were identified from hospital database. All patients presenting acutely with neck of femur fracture above the age of 70 were included, and their case notes were retrospectively reviewed. Reason for histopathological examination were categorised into three screening questions: (Q1) clinical suspicion based on history alone, i.e. neck of femur fracture with no clear history of fall or trauma or preceding hip pain, (Q2) radiological evidence of suspicious abnormality on admission radiographs, (Q3) previous history of malignancy or concurrent malignancy or (Q4) combination of above.

RESULTS

In total, 119 samples of femoral head were sent and 18 patients had a positive histology. The sensitivity and specificity of these questions individually showed very poor correlation to positive histology with lowest for (Q3) previous history of malignancy (0.39 and 0.51, respectively). However, combining Q1 and Q2 the sensitivity is improved to 1.0 (95% CI 1.0-1.0) and specificity to 0.35 (95% CI 0.25-0.44) with a positive predictive value of 0.21 (95% CI 0.13-0.30) and negative predictive value of 1.00 (95% CI 1.00-1.00).

CONCLUSION

History of previous malignancy poorly correlates with positive histology. Routine request based on these screening criteria is not cost-effective in patient management.

LEVEL OF EVIDENCE

Prognostic level III.

Unsuspected Malignancies in Routine Femoral Head Histopathologic Examination During Primary Total Hip Arthroplasty: Cost-Effectiveness Analysis

BACKGROUND

Routine femoral head histopathology during primary total hip arthroplasty (THA) has been recently reported as a potentially useful screening tool for bone- and bone marrow-associated malignancies. However, cost-effectiveness of routine histopathology during THA remains unclear due to low prevalence of significant medical findings which alter patient management. The aim of this study was to evaluate the cost-effectiveness of routine histopathology in diagnosing unsuspected malignancy in patients undergoing primary THA.

METHODS

From 1993 to 2011, we retrospectively analyzed routine histopathologic findings of 3200 femoral head specimens from 2725 patients that underwent primary THA. Preoperative and postoperative diagnoses were classified into concordant (clinical diagnosis concurred with pathologic diagnosis), discrepant (differing diagnosis with no resultant impact on patient management), and discordant (differing diagnosis with subsequent change in patient management). Cost-effectiveness analysis was performed using the incremental cost-utility ratio.

RESULTS

A total of 3055 of 3200 pathologic samples were concordant with the preoperative diagnosis (95.4%), 140 of 3200 were discrepant (4.4%), and 5 of 3200 were discordant (0.2%). Routine histopathology revealed 1 unsuspected malignancy out of 640 (5 of 3200) femoral heads. The total cost of histopathologic screening was $614,664.80. The average cost to identify a discrepant case was $4390.46, and the cost to identify a discordant case was $122,932.96. The incremental cost-utility ratio was $49,569.74 per quality-adjusted life year (QALY) gained.

CONCLUSION

Our study indicates routine femoral head histopathology may be cost-effective in diagnosing unsuspected malignancy at $49,569.74/QALY gained (less than World Health Organization recommended threshold $159,000/QALY gained), providing useful clinical information for surgeons considering the value of routine femoral head histopathology in patients undergoing THA.

Metal-on-metal joint bearings and hematopoetic malignancy

This is a review of the hip arthroplasty era. We concentrate on new metal bearings, surface replacements, and the lessons not learned, and we highlight recent reports on malignancies and joint implants. A low incidence of blood malignancies has been found in bone marrow taken at prosthetic surgery. The incidence is increased after replacement with knee implants that release very low systemic levels of metal ions. A carcinogenic effect of the high levels of metal ions released by large metal-on-metal implants cannot be excluded. Ongoing Swedish implant registry studies going back to 1975 can serve as a basis for evaluation of this risk.