title: Minimizing alteration of posterior tibial slope during opening wedge high tibial osteotomy: a protocol with experimental validation in paired cadaveric knees.
abstract: BACKGROUND
  The High Tibial Osteotomy (HTO) is a reliable procedure in addressing uni- compartmental arthritis with associated coronal deformities. With osteotomy of the proximal tibia, there is a risk of altering the tibial slope in the sagittal plane. Surgical techniques continue to evolve with trends towards procedure reproducibility and simplification. We evaluated a modification of the Arthrex iBalance technique in 18 paired cadaveric knees with the goals of maintaining sagittal slope, increasing procedure efficiency, and decreasing use of intraoperative fluoroscopy.
  
  
  METHODS
  Nine paired cadaveric knees (18 legs) underwent iBalance medial opening wedge high tibial osteotomies. In each pair, the right knee underwent an HTO using the modified technique, while all left knees underwent the traditional technique. Independent observers evaluated postoperative factors including tibial slope, placement of hinge pin, and implant placement. Specimens were then dissected to evaluate for any gross muscle, nerve or vessel injury.
  
  
  RESULTS
  Changes to posterior tibial slope were similar using each technique. The change in slope in traditional iBalance technique was -0.3° ±2.3° and change in tibial slope using the modified iBalance technique was -0.4° ±2.3° (p=0.29). Furthermore, we detected no differences in posterior tibial slope between preoperative and postoperative specimens (p=0.74 traditional, p=0.75 modified). No differences in implant placement were detected between traditional and modified techniques. (p=0.85). No intraoperative iatrogenic complications (i.e. lateral cortex fracture, blood vessel or nerve injury) were observed in either group after gross dissection.
  
  
  CONCLUSIONS
  Alterations in posterior tibial slope are associated with HTOs. Both traditional and modified iBalance techniques appear reliable in coronal plane corrections without changing posterior tibial slope. The present modification of the Arthrex iBalance technique may increase the efficiency of the operation and decrease radiation exposure to patients without compromising implant placement or global knee alignment.
authors.affiliation: University of Iowa Hospitals and Clinics Department of Orthopaedics and Rehabilitation.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Westermann
authors.affiliation: New England Musculoskeletal Institute UConn Health Center.
authors.forename: Thomas
authors.initials: T
authors.lastname: DeBerardino
authors.affiliation: University of Iowa Hospitals and Clinics Department of Orthopaedics and Rehabilitation.
authors.forename: Annunziato
authors.initials: A
authors.lastname: Amendola
mesh_terms: D000328:Adult; D000368:Aged; D006801:Humans; D007717:Knee / Q000601:surgery*; D007719:Knee Joint / Q000601:surgery*; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D013977:Tibia / Q000601:surgery*