Double-tapered conical taper in primary and revision surgery: rationale and short-term follow-up.

BACKGROUND

: The new double-conical tapered stem is a novel cementless modular system, which is indicated for both primary and revision surgeries. It has been designed with different angles at the proximal (5°) and distal sections (1° 36') in order to obtain optimal fixation by proximal and distal fit and fill of the femoral canal.

AIM:: The aim of this prospective study was to evaluate the short-term clinical and radiographic outcomes of primary and revision hip surgery with the new double-conical stem.

METHODS

: 61 stems were implanted (December 2013 to September 2016) in 42 cases of primary and in 19 cases of revision surgery. The mean age of patients was 64.7 (17-94; standard deviation [SD] 21.9) years.

RESULTS

: The mean body mass index of the patients was 24.6 (17-34.6). In 3 cases of developmental dysplasia of the hip we performed femoral shortening osteotomy. The mean follow-up was 26 (8-40) months. 3 patients died due to causes unrelated to surgery. Postoperative complications included 3 hip dislocations, 2 infections and 1 case of stem explant for metastatic tumour. For all other cases, at the last follow-up radiographs showed no loosening, no radiolucent lines nor subsidence. The mean Harris Hip Score significantly improved from 45 (range 35-58) preoperatively to 87 (range 75-94). Leg length discrepancy was found in 10% of cases but never >1 cm.

CONCLUSIONS

: Radiographic analysis showed the bone-stem contact full at 2 levels of taper. The double-tapered prosthetic stem can therefore be usefully employed both in primary and in revision surgeries.