Woodpecker device proven safe, effective in direct anterior hip replacement surgery

A novel pneumatic broaching system, called Woodpecker, has shown favourable safety profile and effectiveness as an alternative tool in minimally invasive direct anterior hip replacement surgery for femoral broaching performed on a standard table, reports a study.

“The Woodpecker pneumatic broaching system facilitates femoral preparation to achieve optimal primary fixation of the stem in direct anterior hip replacement using a standard operating table,” the researchers said. “The high-frequency axial impulses of the device reduce excess bone tension, intraoperative femoral fractures, and overall operating time.”

The Woodpecker device was used in 649 primary elective anterior bikini total hip arthroplasties (THA) over a 5-year period. Patients (n=219) who underwent THA through a different surgical approach, revision THA, or arthroplasties for hip fractures were excluded.

The researchers then analysed pre- and postoperative Harris Hip Scores (HHS) and postoperative radiographs to identify femoral fractures and femoral component positioning. They also examined complications and component survivorship until most recent follow-up.

Of the 649 patients (mean age, 69 years; mean body mass index, 28.3 kg/m²), 317 underwent left THA, 328 right THA, and two bilateral THA. Additionally, 521 patients (80 percent) underwent uncemented and 128 (20 percent) cemented femoral components.

The average time taken to broach the femur using the Woodpecker device was 2.8 min (range, 1.4–7.5 min) in both cemented and uncemented cases. In majority of the patients (91 percent), the templated broach size was achieved with the remaining 9 percent within ±1 size of the planned template. [Orthop Proc 2020;102-B:142]

In radiographic analysis, 67.3 percent of the stems were placed in 0–1.82 degrees of varus and 32.7 percent placed in 0–1.4 degrees of varus. Mean preoperative HHS was 24.4, with robust improvements seen at 6 weeks (80.95), 6 months (91.91), and 12 months (94.18) after surgery. [BMJ Innovations 2021;doi:10.1136/bmjinnov-2020-000536]

During trial reduction, three patients (0.4 precent) had intraoperative femoral fractures; three more patients had periprosthetic postoperative fractures (0.4 percent) from falls, two had stem subsidence (0.3 percent), and two had wound infections (0.3 percent).

Survivorship of the acetabular and femoral components at the most recent follow-up (mean, 2.9 years; range, 0.5–5 years) were 99.7 percent and 99.1 percent, respectively. These intra- and postoperative complications, however, were not directly attributed to the Woodpecker broaching system.

“The skill and experience of the surgeon must be taken into consideration when utilizing new surgical devices,” the researchers said.

A recent study by Alva and colleagues, which analysed the complications, clinical outcomes, and implant survivorship of 865 direct anterior approach (DAA) THAs over 6 years, suggested that the bikini incision DAA technique can be safely used to perform THA. [J Exp Orthop 2021;doi:10.1186/s40634-020-00318-7]

“The Woodpecker device provides uniformity and enhanced control while broaching, optimizing cortical contact between the femur and implant and thereby maximizing prosthetic axial stability and longevity,” the researchers said.