title: Impingement-free range of movement, acetabular component cover and early clinical results comparing 'femur-first' navigation and 'conventional' minimally invasive total hip arthroplasty: a randomised controlled trial.
abstract: We report the kinematic and early clinical results of a patient- and observer-blinded randomised controlled trial in which CT scans were used to compare potential impingement-free range of movement (ROM) and acetabular component cover between patients treated with either the navigated 'femur-first' total hip arthroplasty (THA) method (n = 66; male/female 29/37, mean age 62.5 years; 50 to 74) or conventional THA (n = 69; male/female 35/34, mean age 62.9 years; 50 to 75). The Hip Osteoarthritis Outcome Score, the Harris hip score, the Euro-Qol-5D and the Mancuso THA patient expectations score were assessed at six weeks, six months and one year after surgery. A total of 48 of the patients (84%) in the navigated 'femur-first' group and 43 (65%) in the conventional group reached all the desirable potential ROM boundaries without prosthetic impingement for activities of daily living (ADL) in flexion, extension, abduction, adduction and rotation (p = 0.016). Acetabular component cover and surface contact with the host bone were > 87% in both groups. There was a significant difference between the navigated and the conventional groups' Harris hip scores six weeks after surgery (p = 0.010). There were no significant differences with respect to any clinical outcome at six months and one year of follow-up. The navigated 'femur-first' technique improves the potential ROM for ADL without prosthetic impingement, although there was no observed clinical difference between the two treatment groups.
authors.affiliation: Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077 Bad Abbach, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Renkawitz
authors.affiliation: Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077 Bad Abbach, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Weber
authors.affiliation: Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077 Bad Abbach, Germany.
authors.forename: H-R
authors.initials: HR
authors.lastname: Springorum
authors.affiliation: Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077 Bad Abbach, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Sendtner
authors.affiliation: Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077 Bad Abbach, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Woerner
authors.affiliation: Technische Universität München, Institut für Medizinische Statistik und Epidemiologie, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Ulm
authors.affiliation: Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077 Bad Abbach, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Weber
authors.affiliation: Regensburg University Medical Centre, Asklepios Klinikum Bad Abbach, Kaiser-Karl V.-Allee 3, 93077 Bad Abbach, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Grifka
mesh_terms: D000077:Acetabulum; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D005269:Femur; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D011446:Prospective Studies; D011474:Prosthesis Design; D016059:Range of Motion, Articular
keywords: THA; combined anteversion; computer-assisted orthopaedic surgery