title: Aperture fixation instead of transverse tunnels at the patella for medial patellofemoral ligament reconstruction.
abstract: OBJECTIVE
  Medial patellofemoral ligament (MPFL) reconstruction is an effective option for the treatment of recurrent patellar instability. Most techniques utilize the passage of a tendon graft through tunnels at the patella with the risk of patellar fracture. The purpose of this study was to investigate the strength of the recent MPFL reconstruction techniques (transverse tunnel, interference screw, anchor, and docking technique).
  
  
  METHODS
  Thirty-six saw bones were divided into four groups (transverse tunnel, interference screw, anchor fixation, and docking technique) with nine patellae in each. Patella-tendon constructs were pre-loaded to 10 N and cyclically loaded for 20 cycles from 2 to 30 N under load control at a rate of 5 N/sec. The construct was then tested to failure at a constant displacement rate of 6 mm/sec. Ultimate load (N), stiffness (N/mm), and failure mode were recorded for each specimen.
  
  
  RESULTS
  The docking group had lower ultimate load [106 (SD 41) N] and stiffness [14 (SD 2) N/mm] values than the other groups tested (P = 0.007). The anchor group had lower stiffness [21 (SD 6) N/mm] values than the tunnel group [28 (SD 3) N/mm (P = 0.01)] and the interference screw group [31 (SD 6) N/mm, (P = 0.004)]. There was no significant difference in the ultimate load between anchor [299 (SD 116) N], tunnel [304 (SD 140) N], and interference screw groups [241 (SD 103) N] (n.s.).
  
  
  CONCLUSIONS
  Aperture fixation techniques, especially interference screw fixation, were as strong as the technique utilizing tunnels in the patella for MPFL reconstruction.
authors.affiliation: Department of Orthopaedic Surgery, Mustafa Kemal University, Antakya, Hatay Province, Turkey. onurhapa@gmail.com
authors.forename: Onur
authors.initials: O
authors.lastname: Hapa
authors.forename: Ertuğrul
authors.initials: E
authors.lastname: Akşahin
authors.forename: Raif
authors.initials: R
authors.lastname: Özden
authors.forename: Murad
authors.initials: M
authors.lastname: Pepe
authors.forename: Ahmet Nedim
authors.initials: AN
authors.lastname: Yanat
authors.forename: Yunus
authors.initials: Y
authors.lastname: Doğramacı
authors.forename: Ergun
authors.initials: E
authors.lastname: Bozdağ
authors.forename: Emin
authors.initials: E
authors.lastname: Sünbüloğlu
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D007593:Joint Instability / Q000209:etiology / Q000601:surgery; D008023:Ligaments, Articular / Q000293:injuries / Q000601:surgery*; D010329:Patella / Q000502:physiology / Q000601:surgery*; D031222:Patellar Dislocation / Q000150:complications; D057071:Patellofemoral Joint / Q000293:injuries / Q000502:physiology / Q000601:surgery*; D013710:Tendons / Q000502:physiology / Q000601:surgery / Q000637:transplantation*; D053656:Tenodesis / Q000295:instrumentation / Q000379:methods*; D016474:Weight-Bearing