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

Abstract

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.