title: Does computer-assisted surgery improve postoperative leg alignment and implant positioning following total knee arthroplasty? A meta-analysis of randomized controlled trials?
abstract: OBJECTIVE
  Computer-assisted surgery has been proposed as a technique to improve implant alignment during total knee arthroplasty (TKA). However, there is still a debate over the accuracy of placing the femoral and tibial components using computer-assisted systems in TKA. The aim of this study is to establish whether computer-assisted surgery leads to superior mechanical leg axis and implant positioning than conventional technique in patients with primary TKA.
  
  
  METHODS
  Major electronic databases were systematically searched to identify relevant studies without language restriction. A meta-analysis of 41 randomized controlled trials (RCTs) or quasi-RCTs was performed in a random effects model. A subgroup analysis was conducted by type of navigation system to explore the clinical heterogeneity between these trials. The following radiographic parameters were used to compare computer-assisted surgery with conventional technique: (1) mechanical leg axis, (2) femoral component coronal alignment, (3) tibial component coronal alignment, (4) femoral component sagittal alignment, and (5) tibial component sagittal alignment.
  
  
  RESULTS
  For the mechanical leg axis and coronal positioning of femoral and tibial components, there are statistically significant reductions in the number of patients with malalignment in the CAS group if the outlier cutoff value is ±3 or 2° in the coronal and sagittal planes, respectively. Subgroup analysis demonstrates that CT-free navigation systems provide better alignment than conventional techniques in the coronal and sagittal alignment of femoral components within ±3 and 2°. If the outlier cutoff value for the tibial sagittal alignment is ±2°, the outlier percentages are higher in the CT-free navigation group than in the conventional group. However, there was no significant difference in the tibial sagittal alignment at ±3°.
  
  
  CONCLUSIONS
  Computer-assisted surgery does improve mechanical leg axis and component orientation in TKAs. However, high-quality RCTs are necessary to determine whether surgeons could use computer-assisted techniques to achieve a targeted tibial slope in TKA.
  
  
  METHODS
  Therapeutic study (Systematic review of Level I/II studies), Level II.
authors: Department of Orthopaedic Surgery, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University School of Medicine, 600 Yisan Road, Shanghai, 200233, People's Republic of China.
authors: Tao
authors: T
authors: Cheng
authors: Song
authors: S
authors: Zhao
authors: Xiaochun
authors: X
authors: Peng
authors: Xianlong
authors: X
authors: Zhang
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D005269:Femur / Q000000981:diagnostic imaging; D006801:Humans; D007720:Knee Prosthesis; D017755:Prosthesis Fitting; D015641:Radiography, Interventional; D016032:Randomized Controlled Trials as Topic; D025321:Surgery, Computer-Assisted; D013977:Tibia / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed