Evaluation of a Novel Use of a Digital Optical Microscope to Assess Bone Ingrowth in Prosthetic Joint Replacements


Douglas E. Padgett, MD

Project Description

Initial fixation of prosthetic implants to bone relied upon the use of acrylic bone cement for fixation. Unfortunately, over time the cement would fatigue and lead to prosthetic loosening.  The development of biologic fixation of implants to bone with the use of porous implants has lead to improved durability.  Recently, there has been a movement to change the shape and texture of the porous implant surface by using more complex 3-dimensional configuration with the hope of enhanced fixation.  Whether this leads to improved fixation is not known. The assessment of the extent of bone ingrowth into traditional porous implants has been determined by detecting back-scattered electrons (BSE) during scanning electron microscopy, an accurate but timely and costly technique.  These 1st generation porous implants were largely made out of titanium alloy and were compatible with this technique.  The recent shift to the 3-D surfaces has employed implants made of both titanium and tantalum, another biologically friendly metal.  Unfortunately, the use of BSE techniques to assess fixation has proven difficult with implants made from tantalum in addition to the time and cost associated. We have recently started investigating the use of a high resolution optical microscope combined with histological staining techniques to determine if the same metrics for evaluation of bone ingrowth, namely extent and depth of penetration of bone into the porous coating, could be attained with this instrument. 

Role of Student:

Learn the basics of the use of the optical microscope. Be exposed to our retrieval lab and understand the types of porous-coated implants that we remove from patients. Using the microscope, assess the regions of interest for bone ingrowth and correlate these with the data from BSE attained with titanium implants.

This position has been filled.