This Article Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal My Folders Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Yuan, X. Articles by Lidgren, L. Search for Related Content PubMed PubMed Citation Articles by Yuan, X. Articles by Lidgren, L.

Roentgen single-plane photogrammetric analysis (RSPA)

A NEW APPROACH TO THE STUDY OF MUSCULOSKELETAL MOVEMENT

Imaging Laboratory, The John P. Robarts Research Institute, London, Ontario, Canada.

L. Ryd, MD, PhD, Associate Professor, Head

Department of Orthopaedics, University Hospital, S-581 85 Linköping, Sweden.

K. E. Tanner, D Phil, Professor of Biomedical Materials

Queen Mary & Westfield College, University of London, London, UK.

L. Lidgren, Professor and Chairman

Department of Orthopaedics, University Hospital, S-221 85 Lund, Sweden.

Correspondence should be sent to Dr L. Ryd.

We present a new approach for the accurate reconstruction of three-dimensional skeletal positions using roentgen single-plane photogrammetric analysis (RSPA). This technique uses a minimum of three markers embedded in each segment which allow continuous, real-time, internal skeletal movement to be measured from single-plane images, provided that the precise distance between the markers is known.

A simulation study indicated that the error propagation in this approach is influenced by focus position, object position, the number of control points, the accuracy of the previous measurement of the distance between markers and the accuracy of image measurement. For reconstruction of normal movement of the knee with an input measurement error of SD = 0.02 mm, the rotational and translational differences between reconstructed and original movement were less than 0.27° and 0.9 mm, respectively.

Our results showed that the accuracy of RSPA is sufficient for the analysis of most movement of joints. This approach can be applied in combination with force measurements for dynamic studies of the musculoskeletal system.