The science of walking sticks and related matters

Joe Perry of Aerosmith genuinely uses a walking stick!

A minority of orthopaedic surgeons are entirely at ease with biomechanics, I would say. I am in the slightly perturbed majority. However, all orthopaedic 'exit exams' of which I'm aware will include it, reasonably enough. Drawing free body diagrams, explaining joint reaction forces, discussing the rationale of prosthetic design etc

Happily, as Isaac Newton has amply demonstrated, the principles have been established for centuries, and so the two papers here, from 1959 and 1997, seem bang up to date.

The first, by Robin Denham, one of the relatively unsung heroes of British orthopaedics, is as nice an exposition of basic hip mechanics as you could wish for. He references Blount's classic JBJS article "Don't Throw Away the Cane", and the end of Denham's piece has a great little exposition of the use of a walking stick (cane), which includes why patients will intuitively hold it in the opposite hand from the affected hip. The final 9 points in the summary are in a way all you need to understand for both clinical practice and exams.




The second paper, from Richard Brand in Iowa, is more about osteotomies, and relating the mechanics to the biology. Proximal tibial osteotomy for knee arthritis is definitely on the way up again, and periacetabular osteotomy in adults is an essential part of the hip repertoire now. Proximal femoral osteotomy in adults though is not really on the same page. There seem to be very few patients in whom it would be a better bet than a hip replacement. The last one I did was for a varus proximal femur causing stress fractures, ages ago (it did work). The bottom line is, if you absorb these two papers you know a lot about hip mechanics. if you're like me, and you get most of the content, that's enough to function perfectly well.

If you add in Charnley's stuff on wear and head size, you're almost an expert. Almost