Structural Comparison of the Finger Proximal Interphalangeal Joint Surfaces and Those of the Third Toe: Suitability for Joint Reconstruction

Abstract

This study compared the degree of surface structural similarity between finger proximal interphalangeal joints and third toe articular surfaces to assess the appropriateness of using partial toe articular osteochondral grafts for finger joint reconstruction. Computer models were generated from 4 paired cadaver hands and feet and compared the radius of curvature of toe and finger articular surfaces. The angle created by the palmar divergence of adjacent condyles of the same phalanx was also compared and described as the angular difference. The distal articular surfaces of the third toe proximal and middle phalanx were compared to distal articular surfaces of all 4 finger proximal phalanges. The radius of curvature was also compared between the third toe middle phalanx base and those of all 4 fingers. The toe middle phalanx medial and lateral condyles were 66% and 60% the size of the respective finger condyles. The mean angular difference between adjacent condyles of the toe middle phalanx compared to the finger was 20°. The toe proximal phalanx medial and lateral condyles were 75% and 70% the size of the respective finger condyles, with a mean angular difference between adjacent condyles of 6°. The toe middle phalanx medial base was closer in size to that of the finger (95% to 178%) compared to the toe middle phalanx lateral base (205% to 254%). This study revealed that the third toe proximal phalanx distal articular surface more closely matched the geometric characteristics of the finger proximal phalanx distal articular surface than did the toe middle phalanx distal articular surface. The medial base of the toe middle phalanx more closely approximated the size of the finger middle phalanx base than did the lateral toe middle phalanx base. Quantitative data have been provided to help guide third toe osteochondral donor site selection when reconstructing traumatic finger proximal interphalangeal joint defects. Therapeutic IV.