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(A) Anteroposterior (AP) radiograph of the pelvis obtained before a primary THA. (B) Postoperative AP radiograph obtained immediately after primary THA using cementless implants. (C) Postoperative AP radiograph obtained 14 years after surgery. No remarkable changes were noted compared with the radiograph immediately after surgery. (D) Postoperative AP radiograph obtained 19 years after surgery. Although the acetabular side was almost the same as in (C), atrophic changes in the medullary canal (asterisk) and focal ballooning of the cortical bone (white arrow) were noted in the femur at the level of the middle part of the stem. (E) Postoperative AP radiograph obtained 20 years after surgery. Change in the femoral side was more noticeable, and patchy opacity became visible around the cup. (F) Postoperative AP radiograph obtained 21 years after the surgery. The patchy opacity around the cup has the cotton wool appearance characteristic of PDB.
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Her past medical history included renal sclerosis treated with hemodialysis for 15 years, a dissecting aortic aneurysm (DAA) for which she was treated conservatively, and osteoarthritis secondary to developmental dysplasia of the hip, which was treated with a total hip arthroplasty (THA) when she was 48 years old (Fig. 1A,B). The patient was temporarily lost to follow-up but started annual check-ups at our out-patient clinic ten years after the THA (Fig. 1C). She complained of right leg pain again at her 19-year postoperative annual check-up, but an anteroposterior (AP) pelvic radiograph showed no change from her 14-year check-up (Fig. 1D). AP pelvic radiograph showed an expanded mixed osteolytic and osteosclerotic lesion around the neck of the femoral stem (Fig. 1E). At the 21-year postoperative check-up, an AP pelvic radiograph showed further extension of the lesion (Fig. 1F). We reevaluated the x-ray obtained 21 years after the initial THA and recognized that the rapid-onset atypical osteolytic change around the cup without severe polyethylene wear showed a cotton wool appearance characteristic of PDB (Fig. 1F).
(A) Bone scintigraphy obtained 14 years after the primary THA showed slight bone tracer accumulation in the right proximal femur but no obvious accumulation in the anterior pelvic wing or around the cup. Increased activity was noted in the skull. (B) Bone scintigraphy obtained 20 years after the primary THA showed considerable accumulation in the anterior pelvic wing, more than in the circumference of the cup. (C-E) Computed tomography showing mixed osteosclerotic and osteolytic changes in the right iliac wing (arrowheads).
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Technetium-99 m bone scintigraphy showed focal areas of increased activity in the anterior part of the right iliac wing that had not been noted 6 years previously (Fig. 2A,B), and computed tomography (CT) showed mixed osteosclerotic and osteolytic changes in the right iliac wing (Fig. 2C-E). Of interest, although unnoticed when evaluating the patient for the first cup revision arthroplasty, increased activity in the skull was seen on the bone scan taken 14 years after the primary THA (Fig. 2A).
(A) Postoperative AP radiograph obtained immediately after revision arthroplasty using a jumbo trabecular cup. (B) Postoperative AP radiograph obtained one year after revision arthroplasty with the jumbo trabecular cup, showing obvious dislodgement of the cup.
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A cementless jumbo cup (Zimmer 56-mm Trabecular cup) was implanted with a 32-mm cobalt-chromium femoral head and a highly cross-linked polyethylene liner (Fig. 3A).
Histologically, thick cement lines were noted that demarcate randomly oriented lamellar bone characterized as a mosaic pattern, indicating a mix of findings compatible with PDB. (Hematoxylin and eosin stain).
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However, a mosaic pattern with thick cement lines demarcated randomly oriented lamellar bone, a pathognomonic histologic finding of Paget's disease (Fig. 4).
(A) A 3D-printed acetabular model generated using computed tomographic data from the patient. Notable bone defects in the acetabulum were noted, although bone deficiency had not yet led to pelvic discontinuity. (B) Preoperative planning for acetabular reconstruction using a crouton-size allograft and molded half femoral head allograft with a Kerboull-type reinforcement device. (C) Intraoperative photos showed severe bone deficiency in the acetabulum. (D) The acetabulum was reconstructed successfully by using a structural allograft and a Kerboull-type reinforcement device. (E) Postoperative AP radiograph obtained immediately after the re-revision arthroplasty.
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Because of the severity of the acetabular bone defect, we prepared a 3D-printed model of this patient's acetabulum when planning the re-revision (Fig. 5A,B). WNL. We removed the trabecular cup and reconstructed the acetabulum, which had severe bone deficiency, by using a structural allograft and a Kerboull-type reinforcement device (Fig. 5C-E).