Reliability and validity of the Metrecom Skeletal Analysis System in the assessment of sagittal plane lumbar angles

Seventeen asymptomatic subjects were examined by the Metrecom Skeletal Analysis System and by lateral lumbar radiography. Measurements of sacral base angle, lumbar curve angle, and lumbosacral disc angle were compared with the values derived from the lumbar radiographs. Repeated readings using the Metrecom showed high intraexaminer reliability in measuring these angles. However, the Metrecom values for the lumbar curve and lumbosacral disc angles showed virtually no agreement with those obtained radiographically, while only a weak agreement existed for the sacral base angle. RELEVANCE: Our results suggest that the Metrecom Skeletal Analysis System (version 2.2) is not a valid technique for the determination of either sacral base angle, lumbar curve angle, or lumbosacral angle. It would appear that the values that it generates are more a reflection of back shape than of osseous positioning.