title: Comparison between patient-specific instruments and conventional instruments and computer navigation in total knee arthroplasty: a randomized controlled trial.
abstract: OBJECTIVE
  The current study investigated the accuracy in achieving proper lower limb alignment and individual component positions after total knee arthroplasty (TKA) with 3 different instrumentation techniques. It was hypothesized that patient-specific instruments (PSI) would achieve more accurate lower limb alignment and component positions compared to conventional instruments (CON).
  
  
  METHODS
  Ninety knees in 81 patients were randomized in 1:1:1 ratio into CON, computer navigation (NAV) and PSI groups to receive TKA. The surgical routines were standardized. The lower limb mechanical axis and individual component positions were assessed on standard radiographs. Tourniquet time, operation time and patients' functional scores were documented.
  
  
  RESULTS
  Conventional instruments and PSI were more likely to result in an excessively flexed femoral component (p = 0.001) compared to NAV. Number of outliers in postoperative lower limb alignment, and other components positions in the coronal and sagittal plane showed no statistically significant difference. The mean tourniquet time and operation time was significantly shorter in CON and PSI groups than NAV group (p < 0.001). Four early complications occurred in the PSI group (p = 0.015). At 3-month follow-up, there was no difference in terms of the knee range of motion and patients' function among the 3 groups.
  
  
  CONCLUSIONS
  No significant radiological and clinical benefit could be demonstrated in using PSI over CON or NAV in TKA. Routine use of PSI is not recommended because of the extra cost and waiting time.
  
  
  METHODS
  I.
authors.affiliation: Department of Orthopaedics and Traumatology, 5/F, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China. yanchunhoi@gmail.com.
authors.forename: Chun Hoi
authors.initials: CH
authors.lastname: Yan
authors.affiliation: Department of Orthopaedics and Traumatology, 5/F, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China.
authors.forename: Kwong Yuen
authors.initials: KY
authors.lastname: Chiu
authors.affiliation: Department of Orthopaedics and Traumatology, 5/F, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China.
authors.forename: Fu Yuen
authors.initials: FY
authors.lastname: Ng
authors.affiliation: Department of Orthopaedics and Traumatology, 5/F, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China.
authors.forename: Ping Keung
authors.initials: PK
authors.lastname: Chan
authors.affiliation: Department of Orthopaedics and Traumatology, 5/F, Queen Mary Hospital, The University of Hong Kong, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China.
authors.forename: Christian Xinshuo
authors.initials: CX
authors.lastname: Fang
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D061646:Operative Time; D011184:Postoperative Period; D016059:Range of Motion, Articular; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods
keywords: Component position; Computer navigation; Functional outcomes; Lower limb alignment; Patient-specific instrumentation; Total knee arthroplasty