title: Biomechanical properties of a new anatomical locking metal block plate for opening wedge high tibial osteotomy: uniplane osteotomy.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the biomechanical properties of a new anatomical locking metal block plate by comparing the initial biomechanical stability of three different fixation constructs for open wedge high tibial osteotomy (HTO).
  
  
  METHODS
  Sawbones composite tibiae were used to make a 10-mm opening osteotomy model with uniplane technique. The osteotomy was secured with three different types of plates: Group I, new osteotomy plate without a metal block (n=5); Group II, new osteotomy plate with a 10-mm metal block (n=5); and Group III, two short metal block plates (n=5). Single load to failure test and staircase load-controlled cyclical failure test were performed. In the single load to failure test, the yield load, maximum failure load, and the displacement of the osteotomy gap were measured. In the staircase cyclical load to failure test, the total number of cycles to failure was recorded. Failure modes were observed during both single and cyclic load tests.
  
  
  RESULTS
  Group II showed the highest yield and ultimate loads (1829±319 N, 3493±1250 N) compared to Group I (1512±157 N, 2422±769 N) and Group III (1369±378 N, 2157±210 N, p<0.05). The displacement of the opening gap in Group II (0.34±0.35 mm) was significantly lesser than the other groups (p<0.05). In the staircase cyclical load to failure test, the total number of cycles to failure was 12,860 at 950 N in Group III, 20,280 at 1,140 N in Group I, and 42,816 at 1,330 N in Group II (p<0.05). All the specimens showed complete fracture of the intact lateral sawbones area and slight displacement of the distal fragment of the specimens in the single load to test. None of the specimens showed deformed or broken screws and plates during the single load to test. During the fatigue test with staircase cyclic loading, no fracture of the lateral sawbones area was observed.
  
  
  CONCLUSIONS
  This study demonstrated that the new anatomical locking metal block plate could provide sufficient primary stability for open wedge HTO. The addition of a metal block to this new plate can increase the stability of the osteotomy compared to the one without a metal block.
authors.affiliation: Department of Orthopaedic Surgery, Korea University Anam Hospital, Seoul, Korea.
authors.forename: Seung-Beom
authors.initials: SB
authors.lastname: Han
authors.affiliation: Department of Orthopaedic Surgery, Korea University Ansan Hospital, Ansan, Korea.
authors.forename: Ji-Hoon
authors.initials: JH
authors.lastname: Bae
authors.affiliation: Department of Biomedical Engineering, Inje University, Gimhae, Korea.
authors.forename: Sung-Jae
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Biomedical Engineering, Inje University, Gimhae, Korea.
authors.forename: Tae-Gon
authors.initials: TG
authors.lastname: Jung
authors.affiliation: Department of Biomedical Engineering, Inje University, Gimhae, Korea.
authors.forename: Kang-Hee
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, Inje University Ilsan Paik Hospital, Ilsan, Korea.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Kwon
authors.affiliation: Department of Orthopaedic Surgery, Inje University Ilsan Paik Hospital, Ilsan, Korea.
authors.forename: Kyung Wook
authors.initials: KW
authors.lastname: Nha
keywords: Anatomical locking metal block plate; High tibial osteotomy; Knee; Stability