title: Progression of bone ingrowth and attachment strength for stability of percutaneous osseointegrated prostheses.
abstract: BACKGROUND
  Percutaneous osseointegrated prosthetic (POP) devices have been used clinically in Europe for decades. Unfortunately, their introduction into the United States has been delayed, in part due to the lack of data documenting the progression of osseointegration and mechanical stability.
  
  
  OBJECTIVE
  We determined the progression of bone ingrowth into porous-coated POP devices and established the interrelationship with mechanical stability.
  
  
  METHODS
  After amputation, 64 skeletally mature sheep received a custom porous-coated POP device and were then randomized into five time groups, with subsequent measurement of percentage of bone ingrowth into the available pore spaces (n = 32) and the mechanical pullout force (n = 32).
  
  
  RESULTS
  Postimplantation, there was an accelerated progression of bone ingrowth (~48% from 0 to 3 months) producing a mean pullout force of 5066 ± 1543 N. Subsequently, there was a slower but continued progression of bone ingrowth (~23% from 3 to 12 months) culminating with a mean pullout force of 13,485 ± 1855 N at 12 months postimplantation. There was a high linear correlation (R = 0.94) between the bone ingrowth and mechanical pullout stability.
  
  
  CONCLUSIONS
  This weightbearing model shows an accelerated progression of bone ingrowth into the porous coating; the amount of ingrowth observed at 3 months after surgery within the porous-coated POP devices was sufficient to generate mechanical stability.
  
  
  CONCLUSIONS
  The data document progression of bone ingrowth into porous-coated POP devices and establish a strong interrelationship between ingrowth and pullout strength. Further human data are needed to validate these findings.
authors.affiliation: Bone and Joint Research Laboratory, George E. Wahlen Department of Veterans Affairs Medical Center, Veterans Affairs Salt Lake City Health Care System, 500 Foothill Drive, Salt Lake City, UT, 84148, USA.
authors.forename: Sujee
authors.initials: S
authors.lastname: Jeyapalina
authors.forename: J Peter
authors.initials: JP
authors.lastname: Beck
authors.forename: Roy D
authors.initials: RD
authors.lastname: Bloebaum
authors.forename: Kent N
authors.initials: KN
authors.lastname: Bachus
mesh_terms: D000671:Amputation, Surgical / Q000009:adverse effects / Q000534:rehabilitation*; D000818:Animals; D001186:Artificial Limbs / Q000009:adverse effects; D001842:Bone and Bones / Q000473:pathology / Q000601:surgery*; D020099:Coated Materials, Biocompatible; D005260:Female; D005552:Forelimb; D008297:Male; D023421:Models, Animal; D016348:Osseointegration; D016062:Porosity; D011474:Prosthesis Design; D011475:Prosthesis Failure; D017755:Prosthesis Fitting; D019919:Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D012756:Sheep; D013314:Stress, Mechanical; D013997:Time Factors; D016474:Weight-Bearing
chemical_list: D020099:Coated Materials, Biocompatible