title: Changes in Patellar Height After Opening Wedge and Closing Wedge High Tibial Osteotomy: A Meta-analysis.
abstract: To test that patellar height decreases (patellar baja) after opening wedge high tibial osteotomy (HTO) and increases (patellar alta) after closing wedge HTO. In addition, this meta-analysis evaluated whether the method of measuring patellar height affected the change in patellar height after opening and closing HTO.
  
  
  
  Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, all studies comparing pre- and postoperative patellar height using various indices, including the Insall-Salvati index (ISI), Blackburne-Peel index, and Caton Deschamps index, in patients who underwent opening or closing wedge HTO were included. The main outcome of this meta-analysis, mean change in patellar height from before to after surgery, was analyzed with a random effects model. Publication bias was evaluated using funnel plots and Egger's test.
  
  
  
  Twenty-three studies were included in the meta-analysis. Pooled data, including subgroups of the 3 measurement methods, showed that patellar height decreased 7% after opening wedge HTO (95% confidence interval [CI]: 0.05 to 0.10; P < .001), except when patellar height was assessed by ISI (95% CI: -0.02 to 0.06; P = .34), but that there was no change in patellar height after closing HTO (95% CI: -0.01 to 0.04; P = .29).
  
  
  
  The patellar height decreased after opening wedge HTO, except when assessed by ISI. In contrast, patellar height was unchanged after closing wedge HTO, regardless of the measurement method.
  
  
  
  Level II, meta-analysis of Level I and II studies.
authors: Department of Orthopedic Surgery, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors: Seong-Il
authors: SI
authors: Bin
authors: Department of Preventive Medicine, Korea University College of Medicine, Seoul, Republic of Korea.
authors: Hyun-Jung
authors: HJ
authors: Kim
authors: Department of Preventive Medicine, Korea University College of Medicine, Seoul, Republic of Korea.
authors: Hyeong-Sik
authors: HS
authors: Ahn
authors: Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, U.S.A.
authors: Daniel Sungku
authors: DS
authors: Rim
authors: Department of Orthopaedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: eoak22@empal.com.
authors: Dae-Hee
authors: DH
authors: Lee
mesh_terms: D006801:Humans; D020370:Osteoarthritis, Knee / Q000601:surgery; D010027:Osteotomy / Q000379:methods*; D010329:Patella / Q000033:anatomy & histology*; D011184:Postoperative Period; D013977:Tibia / Q000601:surgery*