The Watson Extraction System for removal of well-fixed femoral stems: A retrospective review of 10 cases

Revision of well-fixed cementless femoral stems is a challenging and time-consuming aspect of revision hip arthroplasty. The Watson Extraction System (WES) is a novel, size-specific 3-D fabricated instrument that mimics the outer geometry of the implanted femoral stem. The device acts to cut circumferentially around the stem as it is impacted into place, effectively disrupting the bone-implant interface. This is a retrospective review assessing the experience of 3 fellowship-trained adult reconstruction surgeons who used the WES to extract 10 well-fixed femoral stems during rTHA between 11/7/2020 and 11/7/2022. Outcomes and measures included: ability to remove the stem without a femoral osteotomy, femoral stem extraction time, incidence of femoral fracture, stem type used for reconstruction, blood loss, total surgical time, post-operative complications. No femoral osteotomies were required. The mean time for stem extraction was 7 min (range, 2–13), and there were 2 (20%) intra-operative femoral fractures. The stem type utilized for reconstruction included: 4 (40%) modular, tapered style stems, 3 (30%) antibiotic spacers, 2 (20%) primary style stems, and 1 (10%) ream and broach proximally porous stem. The mean blood loss was 425 ml (range, 200–800), total surgical time was 160 min (range, 107–232), and duration of follow-up was 7 months (range, 2–22 months). The WES may mitigate the need for femoral osteotomy, reduce femoral stem extraction and overall intraoperative time, and decrease blood loss in rTHA. Further, reduced bone loss with use of this device may permit final reconstruction with a primary style stem.