title: Patient-specific instrumentation in total knee arthroplasty provides no improvement in component alignment.
abstract: Improved component alignment in TKA remains a commonly cited benefit of MRI based patient-specific instrumentation (PSI). We hypothesized that PSI would lead to improved alignment versus traditional instrumentation (TI) during primary TKA. Fifty-eight knees (54 patients) that underwent TKA with PSI were compared to 62 knees that had previously undergone TKA with TI. Radiographs were evaluated for mechanical axis and alignment of the femoral and tibial components. Alignment was similar between the groups. However, the PSI group showed fewer knees in the target range for posterior tibial slope (PSI 38% vs. TI 61%, P=0.01) in addition to a trend for fewer knees in target range for femoral flexion (PSI 40% vs. TI 56%, P=0.07). This study demonstrated no improvement in overall alignment and perhaps a worsening of the tibial slope.
authors.affiliation: Department of Orthopaedic Surgery, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Stronach
authors.affiliation: University of Utah, University Orthopaedic Center, Salt Lake City, Utah.
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Pelt
authors.affiliation: University of Utah, University Orthopaedic Center, Salt Lake City, Utah.
authors.forename: Jill A
authors.initials: JA
authors.lastname: Erickson
authors.affiliation: University of Utah, University Orthopaedic Center, Salt Lake City, Utah.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Peters
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000592:standards*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery; D007720:Knee Prosthesis / Q000592:standards*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D058996:Quality Improvement; D011859:Radiography; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome
keywords: MRI; femoral component alignment; patient-specific instrumentation; tibial component alignment; total knee arthroplasty