title: Hip and knee effects after implantation of a drop foot stimulator.
abstract: BACKGROUND
  An active ankle dorsiflexion is essential for a proper gait pattern. If there is a failure of the foot lifting, considerable impairments occur. The therapeutic effect of an implantable peroneus nerve stimulator (iPNS) for the ankle dorsiflexion is already approved by recent studies. However, possible affection for knee and hip motion after implantation of an iPNS is not well described.
  
  
  OBJECTIVE
  The objective of this retrospective study was to examine with a patient cohort whether the use of iPNS induces a lower-extremity flexion withdrawal response in the form of an increased knee and hip flexion during swing phase.
  
  
  METHODS
  Eighteen subjects (12 m/6 w) treated with an iPNS (ActiGait®, Otto Bock, Duderstadt, Germany) were examined in knee and hip motion by gait analysis with motion capture system (Vicon Motion System Ltd®, Oxford, UK) and Plug-in-Gait model after a mean follow up from 12.5 months. The data were evaluated and compared in activated and deactivated iPNS.
  
  
  RESULTS
  Only little changes could be documented, as a slight average improvement in peak knee flexion during stand phase from 1.0° to 2.5° and peak hip flexion in stance from 3.1° to 2.1° In contrast, peak knee flexion during swing appeared similar (25.3° to 25.7°) same as peak hip flexion during swing. In comparison with the healthy extremity, a more symmetric course of the knee flexion during stand phase could be shown.
  
  
  CONCLUSIONS
  No statistical significant improvements or changes in hip and knee joint could be shown in this study. Only a more symmetric knee flexion during stand phase and a less hip flexion during stand phase might be hints for a positive affection of iPNS for knee and hip joint. It seems that the positive effect of iPNS is only based on the improvement in ankle dorsiflexion according to the recent literature.
authors.affiliation: Department of Orthopaedic Surgery, Hannover Medical School, Hannover 30625, Germany.|Department of Orthopaedic Surgery, Hannover Medical School, Hannover 30625, Germany.
authors.forename: Daiwei
authors.initials: D
authors.lastname: Yao
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, University Hospital Bochum, Bochum 44791, Germany.|Department of Orthopaedic Surgery, Hannover Medical School, Hannover 30625, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Lahner
authors.affiliation: Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Hannover 30625, Germany.
authors.forename: Eike
authors.initials: E
authors.lastname: Jakubowitz
authors.affiliation: Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Hannover 30625, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Thomann
authors.affiliation: Department of Orthopaedic Surgery, Hannover Medical School, Hannover 30625, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Ettinger
authors.affiliation: Clinical Trail Management, Hannover Medical School, Hannover 30625, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Noll
authors.affiliation: Department of Orthopaedic Surgery, Hannover Medical School, Hannover 30625, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Stukenborg-Colsman
authors.affiliation: Sporthopaedicum Straubing, Foot and Ankle Surgery, Straubing 94315, Germany.
authors.forename: Kiriakos
authors.initials: K
authors.lastname: Daniilidis
mesh_terms: D000328:Adult; D004599:Electric Stimulation Therapy / Q000379:methods; D004567:Electrodes, Implanted; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D006615:Hip / Q000503:physiopathology*; D006801:Humans; D007717:Knee / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D010543:Peroneal Nerve / Q000503:physiopathology; D016059:Range of Motion, Articular / Q000502:physiology; D012189:Retrospective Studies; D020521:Stroke / Q000150:complications
keywords: Stroke; gait pattern; implantable peroneus nerve stimulator; knee and hip motion