Joint Pain May be 'Hangover' from Evolution, say Scientists

Ever wondered why us humans get so much shoulder, hip and knee pain? Scientists from Oxford University say it's due to a hangover from evolution.

More worrying is that the same scientists say future generations could be at even greater risk, if this trend continues.

The scientists studied more than 300 specimens from different species spanning 400 million years to see how bones changed over extremely long periods of time.

Apparently, the changes occurred when man began standing up straight on two legs.

Dr Paul Monk, of the Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Oxford University, who led the research, wanted to discover why patients in his clinic came in with similar orthopaedic complaints.

"We see certain things very commonly in hospital clinics - pain in the shoulder with reaching overhead, pain in the front of the knee, arthritis of the hip, and in younger people we see some joints that have a tendency to pop out," he said.

By analysing detailed CT scans of 300 ancient specimens housed at the Natural History Museum in London and the Smithsonian Institution in Washington, the team was able to create a library of 3D models and identify changes to the shapes of single bones over millennia.

One particular example is how the so-called 'neck' of the human thigh bone grew broader to support the extra weight as humans started walking upright. Studies have shown that the thicker the neck of the thigh bone, the more likely it is to be affected by arthritis. Scientists say this is one potential reason why humans are susceptible to so much hip pain.