title: Fluctuation of Cup Orientation During Press-Fit Insertion: A Possible Cause of Malpositioning.
abstract: We evaluated real-time angular changes during press-fit cup insertion in 70 total hip arthroplasties. Inclination and anteversion cup angles on navigation system were recorded after each procedure of five hammer blows during cup insertion, and maximum deviated inclination (MDI) and anteversion (MDA) angles until the cup was fully seated were measured. We found 1 (1%) and 29 (41%) hips with increases and decreases in MDI of 5° or more, and 13 (19%) and 6 (8%) hips with increases and decreases in MDA of 5° or more, respectively. The MDI in men was significantly lower and the MDA for left-side surgery was significantly higher. Surgeons should pay attention to fluctuation in angular changes during cup insertion and may consider countermeasures to minimize cup malpositioning.
authors.affiliation: Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishii
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakai
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Takao
authors.affiliation: Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sugano
mesh_terms: D000077:Acetabulum / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012737:Sex Factors; D013314:Stress, Mechanical; D025321:Surgery, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed
keywords: computer navigation; cup orientation; malposition; press-fit cup; total hip arthroplasty