Proof-of-concept of a robotic-driven photogrammetric scanner for
intra-operative knee cartilage repair
Abstract
This work present a proof-of-concept of a robotic-driven intra-operative
scanner designed for knee cartilage lesion repair, part of a system for
direct in vivo bioprinting. The proposed system is based on a
photogrammetric pipeline, which reconstructs the cartilage and lesion
surfaces from sets of photographs acquired by a robotic-handled
endoscope, and produces 3D grafts for further printing path planning. A
validation on a synthetic phantom is presented, showing that —despite
the cartilage smooth and featureless surface— the current prototype
can accurately reconstruct osteochondral lesions and their surroundings
with mean error values of 0.199 ± 0.096 mm but with noticeable
concentration on areas with poor lighting or low photographic coverage.
The system can also accurately generate grafts for bioprinting, although
with a slight tendency to underestimate the actual lesion sizes,
producing grafts with coverage errors of -12.2 ± 3.7, -7.9 ± 4.9 and
-15.2 ± 3.4 % for the medio-lateral, antero-posterior and craneo-caudal
directions respectively. Improvements in lighting and acquisition for
enhancing reconstruction accuracy are planned as future work, as well as
integration into a complete bioprinting pipeline and validation with ex
vivo phantoms.