title: Novel, Patient-Specific Instruments for Acetabular Preparation and Cup Placement.
abstract: BACKGROUND
  Patient-specific implants and instruments (PSI) have been used in both knee and shoulder replacements due to the perceived benefits of improved surgical accuracy and efficiency. The proposed benefits of using a PSI in total hip arthroplasty (THA) are numerous and include reduction of operative time and improved mechanical and anatomical alignment leading to increased implant longevity, increased stability, and clinical outcomes. We describe a novel patient-specific instrumentation and a surgical method that may improve directed resection of acetabular bone and accurate cup placement during THA.
  
  
  METHODS
  In this cadaveric study, 14 acetabuli were used. Pre-operative CT or MRI scans were obtained as part of the acetabular jigs Bullseye Hip Replacement Instruments® (Bullseye Hip Replacement, LLC, Las Vegas, Nevada) protocol. Two senior hip surgeons performed all the operations in accordance to the PSI technique. Post-operative CT scans were obtained and acetabular cup orientation was measured by two independent radiologists.
  
  
  RESULTS
  Fourteen acetabuli were implanted using the Bullseye Hip Replacement Instruments®. Acetabular cup anteversion angle as measured on post-operative CT images averaged, for all 14 acetabuli, 15.50. Acetabular cup abduction/inclination angle as measured on post-operative CT images averaged 35.9°. All implanted components' size/diameter matched the preoperative surgical planned implant size.
  
  
  CONCLUSIONS
  The Bullseye Hip Replacement Instruments® show good reproducible acetabular cup placement in both anteversion and abduction angles, and accurate sizing of the acetabular component. .
authors.affiliation: Department of Orthopaedic Surgery, NYU Langone Medical Center Hospital for Joint Diseases, New York, New York.
authors.forename: Ran
authors.initials: R
authors.lastname: Schwarzkopf
authors.affiliation: Desert Orthopedic Center, Eisenhower Medical Center, Rancho Mirage, California.
authors.forename: Erik
authors.initials: E
authors.lastname: Schnaser
authors.affiliation: Department of Radiological Sciences, University of California, Irvine, Orange, California.
authors.forename: Taiki
authors.initials: T
authors.lastname: Nozaki
authors.affiliation: Department of Radiological Sciences, University of California, Irvine, Orange, California.
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Kaneko
authors.affiliation: Restore Orthopedics Orange, Orange, California.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gillman
mesh_terms: D000077:Acetabulum / Q000033:anatomy & histology / Q000601:surgery; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D002102:Cadaver; D006622:Hip Prosthesis; D006801:Humans; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed