title: A matched-pair comparison of two different locking plates for valgus-producing medial open-wedge high tibial osteotomy: peek-carbon composite plate versus titanium plate.
abstract: OBJECTIVE
  The first purpose of this study was to compare the clinical and radiographic outcome of two different locking plates used for valgus-producing medial open-wedge high tibial osteotomy (HTO). The second purpose was to histologically evaluate peek-carbon wear for biocompatibility.
  
  
  METHODS
  Twenty-six consecutive patients undergoing open-wedge HTO using the first-generation PEEKPower HTO-Plate® (Group I) were matched with 26 patients after open-wedge HTO with the TomoFix™ plate (Group II). Clinical scores (visual analogue scale for pain, WOMAC, Lysholm score) were obtained preoperatively and at a minimum follow-up of 24 months postoperatively. Fixation stability was evaluated radiographically by comparing the medial proximal tibial angle (MPTA) and tibial slope 2 days after open-wedge HTO and after implant removal. Tissue samples of Group I were collected at the time of implant removal for histologic evaluation.
  
  
  RESULTS
  Implant-related complications occurred in 15 % (n = 4) of Group I and 0 % of Group II. Out of them, 3 implant replacements were excluded from statistical analyses. After a final median follow-up of 25 months (range 24-31), the clinical scores in both groups showed significant improvements compared to preoperatively (visual analogue scale, WOMAC, Lysholm score; p < 0.001), without significant group differences (visual analogue scale, n.s.; WOMAC, n.s.; Lysholm score, n.s.). No significant differences between baseline and follow-up measurements for MPTA and tibial slope were observed within each group (MPTA: Gr. I, n.s.; Gr. II, n.s.; tibial slope: Gr. I, n.s.; Gr. II, n.s.) or between the two groups (MPTA, n.s.; tibial slope, n.s.). In histologic samples, CF PEEK abrasion did not induce inflammation or tissue necrosis.
  
  
  CONCLUSIONS
  The first-generation PEEKPower HTO-Plate® provided a higher rate of implant-related complications compared to the TomoFix™ plate at a minimum follow-up of 24 months after valgus-producing open-wedge HTO. Therefore, it is not recommended to use the first-generation PEEKPower HTO-Plate® in the clinical practice.
  
  
  METHODS
  III.
authors.affiliation: Department of Orthopaedic Sports Medicine, Technical University of Munich, Ismaningerstr. 22, 81675, Munich, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Cotic
authors.forename: Stephan
authors.initials: S
authors.lastname: Vogt
authors.forename: Stefan
authors.initials: S
authors.lastname: Hinterwimmer
authors.forename: Matthias J
authors.initials: MJ
authors.lastname: Feucht
authors.forename: Julia
authors.initials: J
authors.lastname: Slotta-Huspenina
authors.forename: Tibor
authors.initials: T
authors.lastname: Schuster
authors.forename: Andreas B
authors.initials: AB
authors.lastname: Imhoff
mesh_terms: D000328:Adult; D001577:Benzophenones; D001860:Bone Plates / Q000009:adverse effects; D002244:Carbon; D020878:Device Removal; D004867:Equipment Design; D005260:Female; D006801:Humans; D007659:Ketones; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D010027:Osteotomy / Q000295:instrumentation*; D011092:Polyethylene Glycols; D011108:Polymers; D011183:Postoperative Complications; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D014025:Titanium
chemical_list: D001577:Benzophenones; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D002244:Carbon; D014025:Titanium