title: Three-dimensional remodelling to determine best fit for hemihamate autograft arthroplasty.
abstract: OBJECTIVE
  To determine the best fit of a hamate osteochondral graft to reconstruct a palmar defect of a middle phalanx articular fracture using three-dimensional remodelling.
  
  
  METHODS
  The proximal middle phalanx and distal hamate articular surfaces of 10 cadaveric right hands were scanned using a three-dimensional laser scanner. A defect was marked on the middle phalanx digital image to simulate a 50% palmar lip fracture. A hemihamate autograft surgical procedure was simulated by aligning the middle phalanx and hamate digital articular surfaces. In addition to the second digit measurements, the midpoint distances of the central ridge of proximal articular surface of the middle phalanx digital image for digits 3, 4 and 5 were recorded for reference value, as well as the offset distances for the long and small finger.
  
  
  RESULTS
  The mean midpoint distance for the index finger was 2.96 mm (95% CI 2.71 mm to 3.21 mm). The mean angle of offset was 20.09° (95% CI 15.54° to 24.64°). The mean graft offset distance was prominent by 1.23 mm (95% CI 0.57 mm to 1.89 mm). The reference values for the third, fourth and fifth middle phalange midpoint distances were 3.26 mm (95% CI 3.09 mm to 3.43 mm), 3.13 mm (95% CI 2.93 mm to 3.33 mm) and 2.48 mm (95% CI 2.33 mm to 2.63 mm), respectively. The offset distances for digits 3 and 5 were 1.24 mm (95% CI 0.48 mm to 2.00 mm) and 1.08 mm (95% CI 0.48 mm to 1.68 mm), respectively.
  
  
  CONCLUSIONS
  The present study provides information about best fit for placing a hamate autograft for the hemihamate arthroplasty procedure. In this model, the hamate graft must be offset to recreate the curvature of the middle phalanx.
authors.affiliation: Division of Plastic & Reconstructive Surgery, University of Toronto, Toronto, Ontario.
authors.forename: Jessica
authors.initials: J
authors.lastname: Shih
authors.affiliation: Division of Plastic & Reconstructive Surgery, University of Toronto, Toronto, Ontario.
authors.forename: Dale
authors.initials: D
authors.lastname: Podolsky
authors.affiliation: Division of Plastic & Reconstructive Surgery, University of Toronto, Toronto, Ontario.
authors.forename: Paul
authors.initials: P
authors.lastname: Binhammer
keywords: 3D remodelling; Hamate arthroplasty; Middle phalanx fracture; Osteochondral graft; Phalanx reconstruction