FLEXIBLE MEDULLO-ENDOSCOPE FOR CEMENT REMOVAL AND BONE BED PREPARATION IN FEMORAL REVISION SURGERY

Abstract

Visualization of the femoral medullar canal is troublesome in revision surgery. To obtain better visual field of the canal and assist cement extraction and following reconstructive procedures, flexible endoscope was applied in femoral revision. Mean age and time to revision of fifteen cemented totally replaced hips were 69.3 (42–83) and 14.9 (3–25) years, respectively. Preoperative status of the revision regarding type of stem loosening was classified as possible in four cases, probable in two, and definite in five classified by Harris et al. No marked finding of loosening was in four. That of bone defect was type I in four cases, Type II in three, and Type III in three by Gustilo. Five cases showed no marked loss of the defect. Extraction of cement mantle was performed under flexible endoscopic inspection. Impaction bone grafting was performed in eight cases. Time for cement removal in association with type of loosening and bone defect were evaluated as well as analysis of periprosthetic complications.

Retained cement mantle was extractable in all cases under good exposure and with maintenance of efficient working space. Interfacial granulation and fibrous tissues between bone and cement were easily removed. Endoscopic time for cement removal was 41.7 ± 10.3 minutes in average. It was 51.8 ± 6.2 minutes in no loosening. 41.3 ± 11.1 minutes in possible loosening, 38.5 ± 9.2 minutes in probable loosening, and 35.4 ± 8.3 minutes in definite loosening, which depended on the status of fixation between bone and cement. Type of bone defect also influenced the time. It was 52.4 ± 5.6 minutes in the cases of no marked bone loss, 43.8 ± 3.5 minutes in Gustilo type I, 28.3 ± 3.5 minutes in Type II, and 34.7 ± 2.5 minutes in Type III. The procedure was effective to prepare suitable bone bed for reconstruction, which allowed proper stem settlement and facilitated recovery of bone stock in the cases of impaction bone grafting. Intra-operative blood loss was 377 ml (212 – 1430) and total amount of blood loss including post surgical drainage was 593 ml (316 – 1680). Type of loosening and bone defect did not affect both whole and intra-operative bleeding volume. However, three occult fractures happened, in which two revealed minor cement leakage and one required additional osteosynthesis with extensive approach.

The data indicated that flexible medullo-endoscope could provide good visual field with maintenance of working space, potentially contributing to less invasive femoral revision surgery, if it would be combined with refined device for cement extraction to improve accuracy of the procedure.