Three-dimensional reconstruction of joint surfaces using a microcomputer.

A microcomputer was used to analyse the surface characteristics and geometry of articulating joints. Both hardware configuration and software organisation were described. Data used in this analysis were obtained by sequential resection of entire joints (elbows, metatarsophalangeal joints and knees) secured in an embedding medium. The exposed joint profile after each resection in a bone milling machine was recorded photographically. Each record of freshly cut profile was manually digitised and automatically processed with a desktop microcomputer. The complete structure of these articulating surfaces was reconstructed in three dimensions to be displayed in any desired orientation as a series of parallel, consecutive and uniformly spaced sections. These data have been used to derive information on cartilage thickness, underlying bone structure, orientation and anatomical shape of the joint surfaces. The stored surface geometry may be retrieved at any time for related studies of joint kinematics, joint sizing and prosthetic joint design.