John Paul obituary

John Paul lecturing engineering students at the Royal School of Science and Technological innovation (now the University of Strathclyde) in the early 1950s

The biomedical engineer John Paul, who has died aged 86, played a crucial role in the improvement of trustworthy complete hip substitute implants, which have improved the lives of excellent numbers of people. John produced the very first sensible estimate of the forces that act on the hip joint throughout perform this information was crucial for the design and style of secure implants and of machines to test them in the laboratory.

In the early 1960s John Charnley, an orthopaedic surgeon, introduced a metal and plastic artificial hip joint with an unnaturally tiny femoral head to decrease the result of friction, ideas incorporated into the productive joints in present use. The very first joints had a metal femoral part and a polytetrafluoroethylene (PTFE) socket fixed to the pelvis. However the PTFE was unsatisfactory and wore out quickly. Employing ultra-substantial molecular weight polyethylene developed considerably much less wear, but numerous of the joints broke, simply because they had been made utilizing unrealistic estimates of the forces that would act on them during perform.

John set out to supply much more reliable estimates of these forces and was in a position to do so because of his deep insight into the engineering rules essential to solve the issue and his meticulous experimental perform.

The forces transmitted across the hip joint are created by the excess weight of the entire body, the accelerations of the entire body and the power in the muscle tissue that generate movement or stability. John designed and developed an instrument to measure the forces made by the body bodyweight. He obtained the accelerations from recording moving volunteers using two cine cameras at right angles. These have been digitised and then analysed.

John identified it more difficult to decide the force in each muscle that affected the joint, which remains a dilemma, but was capable to estimate the forces by grouping together muscle tissues that had a related effect. He showed that the forces on the hip were many instances better than the bodyweight of the body. The magnitude of the joint forces and their variation during walking is recognized as the Paul Cycle, which was, and is, used in the design and style of hip implants.

He was born in Sunderland, exactly where his father, William, was doing work as an engineering draughtsman. John grew up in Outdated Kilpatrick, in the west of Scotland, close to the shipyards in which his father worked, except for the second world war years, which he invested in Aberdeen with two elderly aunts. He was educated at Allan Glen’s college in Glasgow, excelling each academically and on the rugby discipline. He studied mechanical engineering at the Royal School of Science and Engineering (now the University of Strathclyde). The Royal University was unable to award degrees as it was not a university, so John had to consider his BEng finals at Glasgow University. A query came back to the university from the examiners, who asked if there was a possibility of his obtaining cheated, simply because they could not feel that an undergraduate could know so much.

In 1962 he was a founding member of the bioengineering unit at the University of Strathclyde with Robert Kenedi and Tom Gibson. I met John in 1966 when I studied for an MSc at the unit he was one of the supervisors of my analysis thesis. In 1970 I joined the workers. John was head of the unit from 1977 till he retired from the university in 1992. His published research on hip joint forces, such as his PhD thesis, are classic reference operates. With colleagues at the unit he extended his perform to the knee, ankle and elbow joints.

The bioengineering unit rapidly became an internationally popular centre of excellence and John started to travel the world to present his investigation and motivate the advancement of fledgling bioengineering centres. John was chairman of the global standard organisation committee on bone and joint replacement and the equivalent committees of the European and British common organisations. He was president of the Global Society of Biomechanics (1987-90) and a fellow of the Royal Academy of Engineering and the Royal Society of Edinburgh. He continued these routines until just ahead of his death.

John’s popularity is based mostly on function that he initiated 50 many years ago, but which remains relevant these days. The Paul Cycle is the canonical information used for developing implants. These days implants extremely seldom break, but fail due to particles developed by dress in, which can be investigated employing joint simulators based mostly on his perform.

John’s wife, Bette, whom he married in 1956, died in 2004. He is survived by his kids, Gillian, Graham and Fiona, and 5 grandchildren.

• John Poskitt Paul, bioengineer, born 26 June 1927 died 13 November 2013

John Paul obituary