Morphologic analysis of the distal humerus with special interest in elbow implant sizing and alignment.

This study determined the relationship between the medullary canal axis and the flexion-extension axis of the distal humerus as they relate to implant selection and design for elbow arthroplasty. Computed tomography scans of 40 fresh-frozen cadaveric specimens were analyzed with computer-aided design software. The anterior offset and cubital angle were measured between the 2 axes, and the cross-sectional area and diameter were measured for the medullary canal at various intervals. The anterior offset of the flexion-extension axis from the medullary canal axis was proportional to the length of canal used to determine the stem axis. No correlation was established among the width of the articular surface, anterior-posterior canal curvature, and cubital angle. These findings suggest that modular implants that allow for the variability in the natural anterior bow and articular offset of the distal humerus may enhance proper restoration of the flexion-extension axis of the elbow.

[1]  James A. Johnson,et al.  Variability and repeatability of the flexion axis at the ulnohumeral joint , 2003, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[2]  B. Morrey,et al.  Complications of total elbow arthroplasty. , 1982, Clinical orthopaedics and related research.

[3]  J T Bryant,et al.  Geometry of the humeroulnar joint , 1988, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[4]  B. G. Evans,et al.  A comparison of the mechanical designs of articulating total elbow prostheses , 1988 .

[5]  J. London Kinematics of the elbow. , 1981, The Journal of bone and joint surgery. American volume.

[6]  H E Veeger,et al.  Determination of the optimal elbow axis for evaluation of placement of prostheses. , 1999, Clinical biomechanics.

[7]  James A. Johnson,et al.  Application of screw displacement axes to quantify elbow instability. , 2003, Clinical biomechanics.

[8]  E Y Chao,et al.  Three-dimensional rotation of the elbow. , 1978, Journal of biomechanics.

[9]  E. Chao,et al.  Passive motion of the elbow joint. , 1976, The Journal of bone and joint surgery. American volume.

[10]  T D Brown,et al.  Radiographic determinants of the elbow rotation axis: Experimental identification and quantitative validation , 2000, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[11]  F. Smith,et al.  Measurement of the bony anatomy of the humerus using magnetic resonance imaging , 2002, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[12]  A. Lundberg,et al.  Variation in the position and orientation of the elbow flexion axis. , 2003, The Journal of bone and joint surgery. British volume.

[13]  A. Inglis,et al.  A critical analysis of alignment factors affecting functional outcome in total elbow arthroplasty. , 1986, The Journal of arthroplasty.

[14]  D D Robertson,et al.  Three-Dimensional Analysis of the Proximal Part of the Humerus: Relevance to Arthroplasty* , 2000, The Journal of bone and joint surgery. American volume.

[15]  K N An,et al.  Carrying angle of the human elbow joint , 1984, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[16]  T. Thornhill,et al.  Revision of unstable capitellocondylar (unlinked) total elbow replacement. , 2005, The Journal of bone and joint surgery. American volume.

[17]  Justin Hertzler,et al.  Fatigue crack growth rate does not depend on mantle thickness: an idealized cemented stem construct under torsional loading , 2002, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[18]  J. Nishino,et al.  Total elbow arthroplasty with use of a nonconstrained humeral component inserted without cement in patients who have rheumatoid arthritis. , 1999, The Journal of bone and joint surgery. American volume.

[19]  B F Morrey,et al.  Loose-hinge total elbow arthroplasty. An experimental study of the effects of implant alignment on three-dimensional elbow kinematics. , 1995, The Journal of arthroplasty.

[20]  Peter S. Walker,et al.  Biomechanical basis for elbow hinge-distractor design. , 1987 .

[21]  F. P. Mall On the angle of the elbow , 1905 .