Presentation
Recent fall, injured left hip. Known metastatic breast carcinoma.
Patient Data
Dislocation and dissociation of the left hip tumor prosthesis. The acetabular cup and femoral head have dissociated and migrated intrapelvic. The prosthesis is otherwise intact. There is the fragmentation of the cerclage wiring.
There are suspicious lucencies (right femoral neck and left superior/inferior pubic rami) consistent with known breast carcinoma and lytic metastases.
There are healed left superior and inferior pubic rami fractures.
There are bilateral SI and right hip joint degenerative changes.
Case Discussion
The patient has known metastatic breast carcinoma.
Teaching point: there is a special type of hip prosthesis in this case, specifically a 'tumor prosthesis', utilized for the surgical management of known left hip metastases.
Lytic and lucent lesions may be difficult to differentiate on plain films in the background of osteoporosis as in this instance, however, the presence of the tumor prosthesis should alert to a more sinister pathology.