title: [Function of prosthesis components in lower limb amputees with bone-anchored percutaneous implants : Biomechanical aspects].
abstract: BACKGROUND
  Bone anchorage of an artificial limb has been proven to be an alternative intervention for amputees when prosthesis use is seriously reduced because of stump problems. Little is known about how prosthesis components interact with bone and joints and which potential the optimum use provides with respect to quality of treatment of leg amputees.
  
  
  OBJECTIVE
  Does osseointegration influence the motor activity of residual limbs differently compared with socket prostheses? How should prosthesis components be aligned? What type of prosthetic knee joints should be preferred in transfemoral amputees?
  
  
  METHODS
  Transfer of biomechanical knowledge of socket prosthetics to bone-anchored prostheses. Pilot studies with a limited number of amputees.
  
  
  RESULTS
  Force transmission at the interface between the prosthesis and residual limb stump is completely different for osseointegrated fixation and socket design; however, the number of muscles available for control remains unchanged. Because the iliotibial tract is missing, bending moments of the femur are expected to be greater. Prosthetic alignment is very critical for gait pattern and the basic rules seem to be the same as for socket design. The foot position determines the knee function for below-knee amputees. The position of the femur influences the gait pattern of above-knee amputees. The lowest risk of falls and best functional properties are shown by microprocessor controlled knee joints.
  
  
  CONCLUSIONS
  Osseointegrated leg prostheses have some biomechanical advantages over the socket design. Since rehabilitation quality is clearly affected the prosthetic alignment has to be done carefully and precisely. As a rule microprocessor controlled knee joints are indicated.
authors.affiliation: ZHT Zentrum für Healthcare Technology, PFH Private Hochschule Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Deutschland. blumentritt@pfh.de.
authors.forename: S
authors.initials: S
authors.lastname: Blumentritt
mesh_terms: D000671:Amputation, Surgical / Q000295:instrumentation / Q000534:rehabilitation; D000672:Amputation Stumps / Q000601:surgery*; D019643:Arthroplasty, Replacement / Q000295:instrumentation / Q000379:methods; D001186:Artificial Limbs; D000069343:Bone-Implant Interface; D019245:Compressive Strength / Q000502:physiology; D000067190:Exoskeleton Device; D006621:Hip Joint / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007595:Joint Prosthesis; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D007866:Leg / Q000503:physiopathology / Q000601:surgery; D008954:Models, Biological; D016348:Osseointegration; D010865:Pilot Projects; D020127:Recovery of Function / Q000502:physiology; D053441:Suture Anchors; D016896:Treatment Outcome; D016474:Weight-Bearing / Q000502:physiology*
keywords: Biomechanics; Force transmission; Knee joint; Prosthesis alignment; Prosthesis components