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Standardized loads acting in knee implants

Standardized loads acting in knee implants
Standardized loads acting in knee implants
The loads acting in knee joints must be known for improving joint replacement, surgical procedures, physiotherapy, biomechanical computer simulations, and to advise patients with osteoarthritis or fractures about what activities to avoid. Such data would also allow verification of test standards for knee implants. This work analyzes data from 8 subjects with instrumented knee implants, which allowed measuring the contact forces and moments acting in the joint. The implants were powered inductively and the loads transmitted at radio frequency. The time courses of forces and moments during walking, stair climbing, and 6 more activities were averaged for subjects with I) average body weight and average load levels and II) high body weight and high load levels. During all investigated activities except jogging, the high force levels reached 3,372–4,218N. During slow jogging, they were up to 5,165N. The peak torque around the implant stem during walking was 10.5 Nm, which was higher than during all other activities including jogging. The transverse forces and the moments varied greatly between the subjects, especially during non-cyclic activities. The high load levels measured were mostly above those defined in the wear test ISO 14243. The loads defined in the ISO test standard should be adapted to the levels reported here. The new data will allow realistic investigations and improvements of joint replacement, surgical procedures for tendon repair, treatment of fractures, and others. Computer models of the load conditions in the lower extremities will become more realistic if the new data is used as a gold standard. However, due to the extreme individual variations of some load components, even the reported average load profiles can most likely not explain every failure of an implant or a surgical procedure.
1932-6203
e86035-[12pp]
Bergmann, Georg
9103a1c1-3bc2-4356-a274-8969fcb1e74b
Bender, Alwina
9ad782aa-94a5-4a06-a908-ccf7344fac74
Graichen, Friedmar
6f000d0a-22ad-4324-9cea-3bd75401b6f3
Dymke, Joern
9d3fa7e5-616f-4182-bb10-0bfc901a38b9
Rohlmann, Antonius
2a29697c-6b23-4b00-a600-593c34315493
Trepczynski, Adam
76476dda-3d55-42d7-844d-566933e97a28
Heller, Markus O.
3da19d2a-f34d-4ff1-8a34-9b5a7e695829
Kutzner, Ines
78d5837f-7c5e-4477-b386-1bb6693e06c1
Bergmann, Georg
9103a1c1-3bc2-4356-a274-8969fcb1e74b
Bender, Alwina
9ad782aa-94a5-4a06-a908-ccf7344fac74
Graichen, Friedmar
6f000d0a-22ad-4324-9cea-3bd75401b6f3
Dymke, Joern
9d3fa7e5-616f-4182-bb10-0bfc901a38b9
Rohlmann, Antonius
2a29697c-6b23-4b00-a600-593c34315493
Trepczynski, Adam
76476dda-3d55-42d7-844d-566933e97a28
Heller, Markus O.
3da19d2a-f34d-4ff1-8a34-9b5a7e695829
Kutzner, Ines
78d5837f-7c5e-4477-b386-1bb6693e06c1

Bergmann, Georg, Bender, Alwina, Graichen, Friedmar, Dymke, Joern, Rohlmann, Antonius, Trepczynski, Adam, Heller, Markus O. and Kutzner, Ines (2014) Standardized loads acting in knee implants. PLoS ONE, 9 (1), e86035-[12pp]. (doi:10.1371/journal.pone.0086035).

Record type: Article

Abstract

The loads acting in knee joints must be known for improving joint replacement, surgical procedures, physiotherapy, biomechanical computer simulations, and to advise patients with osteoarthritis or fractures about what activities to avoid. Such data would also allow verification of test standards for knee implants. This work analyzes data from 8 subjects with instrumented knee implants, which allowed measuring the contact forces and moments acting in the joint. The implants were powered inductively and the loads transmitted at radio frequency. The time courses of forces and moments during walking, stair climbing, and 6 more activities were averaged for subjects with I) average body weight and average load levels and II) high body weight and high load levels. During all investigated activities except jogging, the high force levels reached 3,372–4,218N. During slow jogging, they were up to 5,165N. The peak torque around the implant stem during walking was 10.5 Nm, which was higher than during all other activities including jogging. The transverse forces and the moments varied greatly between the subjects, especially during non-cyclic activities. The high load levels measured were mostly above those defined in the wear test ISO 14243. The loads defined in the ISO test standard should be adapted to the levels reported here. The new data will allow realistic investigations and improvements of joint replacement, surgical procedures for tendon repair, treatment of fractures, and others. Computer models of the load conditions in the lower extremities will become more realistic if the new data is used as a gold standard. However, due to the extreme individual variations of some load components, even the reported average load profiles can most likely not explain every failure of an implant or a surgical procedure.

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e-pub ahead of print date: 23 January 2014
Published date: 23 January 2014
Organisations: Bioengineering Group

Identifiers

Local EPrints ID: 361543
URI: http://eprints.soton.ac.uk/id/eprint/361543
ISSN: 1932-6203
PURE UUID: 555770ac-a342-471a-801b-f0858ca532d8
ORCID for Markus O. Heller: ORCID iD orcid.org/0000-0002-7879-1135

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Date deposited: 27 Jan 2014 14:43
Last modified: 18 Feb 2021 17:19

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