Compressive osseointegration into a custom acetabular implant masquerading as tumor recurrence: a case report.
BACKGROUND
Compressive osseointegration is a durable method of method of achieving fixation in long-bone reconstruction, and radiographic findings are well described. The radiographic appearance of integration into the pelvis is poorly defined in the available literature.


METHODS
We describe a 50-year-old man with a localized chondrosarcoma of the pelvis treated with wide resection and reconstruction using a custom acetabular device that used compressive osseointegration for fixation. A linear area of sclerosis was identified at the patient's 3-month followup surveillance film, which was concerning for tumor recurrence. We used PET-CT to document the absence of worrisome hypermetabolism and to support our suspicion that the abnormalities seen on a surveillance CT scan represented bony integration into the custom acetabular component rather than tumor recurrence.


METHODS
The use of FDG-PET for staging and surveillance of chondrosarcoma is presently evolving. Several articles suggest it may be useful in differentiating low-grade chondrosarcoma from benign lesions.


CONCLUSIONS
We found PET-CT useful to differentiate the midterm radiographic appearance of the remodeling produced by compressive implant osseointegration from local recurrence.
Department of Orthopaedic Surgery, Mayo Clinic Arizona, 5777 E Mayo Boulevard, Phoenix, AZ 85054, USA. schwartz.adam@mayo.edu
Adam J
AJ
Schwartz
Christopher P
CP
Beauchamp
D000077:Acetabulum / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D002813:Chondrosarcoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D003937:Diagnosis, Differential; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D016348:Osseointegration; D010027:Osteotomy; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D019651:Plastic Surgery Procedures / Q000295:instrumentation*; D012598:Sclerosis; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome