[54] KNEE JOINT LOAD MEASURING
INSTRUMENT AND JOINT PROSTHESIS
[75] Inventor: Nebojsa Kovacevic, Plymouth, Minn.
[73] Assignee: N. K. Biotechnical Engineering Co.,
Minneapolis, Minn.
[21] Appl. No.: 681,099
[22] Filed: Apr. 5,1991
[51] Int. CI.5 A61B 5/103
[52] U.S. a 128/782; 128/774;
606/53; 623/18; 623/20
[58] Field of Search 128/774, 782; 606/90,
606/91, 99, 61, 53; 623/16, 17, 18, 20, 22
[56] References Cited
U.S. PATENT DOCUMENTS
3,916,451 11/1975 Buechel et al 623/18
4,206,517 6/1980 Pappas et al 623/18
4,211,228 7/1980 Cloutier 606/102
4,309,778 1/1982 Buechel et al 623/20
4,340,978 7/1982 Buechel et al 623/20
4,426,884 1/1984 Polchaninoff 73/172
4,501,266 2/1985 McDaniel 606/90
4,503,705 3/1985 Polchaninoff 73/172
4,619,658 10/1986 Pappas et al 623/22
4,624,674 11/1986 Pappas et al 623/22
4,712,542 12/1987 Daniel et al 606/96
4,795,473 1/1989 Grimes 623/23
4,804,000 2/1989 Lamb et al 128/774
4,808,186 2/1989 Smith 623/23
4,822,362 4/1989 Walker et al 623/20
4,834,057 5/1989 McLeod, Jr 128/782
4,932,974 6/1990 Pappas et al 623/16
Primary Examiner—Max Hindenburg
Assistant Examiner—Guy V. Tucker
Attorney, Agent, or Firm—Kinney & Lange
[57] ABSTRACT
A system is disclosed for measuring dynamically forces applied to a prosthetic joint. The system comprises a first support member attached to an outer surface of a first bone, a second support member attached to an outer surface of a second bone and a transducer secured to the second support member and engaging the first support member. The transducer measures forces applied to the first and second support member as the prosthetic joint is articulated and provides a representative force output signal. In the preferred embodiment, the transducer comprises a central body having plurality of integrally formed flexure members, each flexure member defined by a corresponding cavity in the body and defining a force responsive flexure section. A plate is secured to the transducer with support posts to localize forces onto the flexure members. Although the assembly forms components for implementation of a knee prosthetic, the present invention can be adapted to any particular joint of the body.
21 Claims, 4 Drawing Sheets
