A six-degree-of-freedom transducer for in vitro measurement of patellofemoral contact forces

Singerman, Robert; Berilla, J.; Kotzar, G. M.; Daly, Janis J.; Davy, Dwight T.

doi:10.1016/0021-9290(94)90213-5

Cited by 35 publications

(18 citation statements)

References 13 publications

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“…Perry et al [22] using an instrumented cadaver estimated patellar forces of 2.1 times body weight at a knee angle of 60°for standing. Cadaver work by Singerman et al [23] established that at 60°of knee flexion a flexion moment of 5.7 N m resulted in a patello-femoral contact force of 160 N. Combining these data with data from the current study (60°of knee flexion: at 47% of the gait cycle; knee moment: 1.1 N m/kg; subject mass: 65 kg) would predict patello-femoral joint contact forces of 30.9 N/kg, which is very close to the 28.7 N/kg average presented here.…”

Section: Contact and Patellar Forcesmentioning

confidence: 99%

Knee and hip kinetics during normal stair climbing

2002

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Understanding joint kinetics during activities of daily living furthers our understanding of the factors involved in joint pathology and the effects of treatment. In this study, we examined hip and knee joint kinetics during stair climbing in 35 young healthy subjects using a subject-specific knee model to estimate bone-on-bone tibiofemoral and patello-femoral joint contact forces. The net knee forces were below one body weight while the peak posterior-anterior contact force was close to one body weight. The peak distal-proximal contact force was on average 3 times body weight and could be as high as 6 times body weight. These contact forces occurred at a high degree of knee flexion where there is a smaller joint contact area resulting in high contact stresses. The peak knee adduction moment was 0.42 (0.15) N m/kg while the flexion moment was 1.16 (0.24) N m/kg. Similar peak moment values, but different curve profiles, were found for the hip. The hip and knee posterio-anterior shear forces and the knee flexion moment were higher during stair climbing than during level walking. The most striking difference between stair ascent and level walking was that the peak patello-femoral contact force was 8 times higher during stair ascent. These data can be used as baseline measures in pathology studies, as input to theoretical joint models, and as input to mechanical joint simulators.

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Section: Contact and Patellar Forcesmentioning

confidence: 99%

Knee and hip kinetics during normal stair climbing

2002

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“…Direct measurement of the compressive patellofemoral force is difficult in the intact joint because of the need to place the measuring device within the joint; [11][12][13][14] this difficulty is compounded by knee replacement. Several authors, however, have reported large increases in anterior patellar strain after arthroplasty.…”

Section: Discussionmentioning

confidence: 99%

In vitro measurement of patellofemoral force after three types of knee replacement

Miller

Goodfellow

Murray

et al. 1998

The Journal of Bone and Joint Surgery. British volume

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U sing a new, non-invasive method, we measured the patellofemoral force (PFF) in cadaver knees mounted in a rig to simulate weight-bearing. The PFF was measured from 20° to 120° of flexion before and after implanting three designs of knee prosthesis.Medial unicompartmental arthroplasty with a meniscal-bearing prosthesis and with retention of both cruciate ligaments caused no significant change in the PFF. After arthroplasty with a posterior-cruciateretaining prosthesis and division of the anterior cruciate ligament, the PFF decreased in extension and increased by 20% in flexion. Implantation of a posterior stabilised prosthesis and division of both cruciate ligaments produced a decrease in the PFF in extension but maintained normal load in flexion.There was a direct relationship between the PFF and the angle made with the patellar tendon and the long axis of the tibia. The abnormalities of the patellar tendon angle which resulted from implantation of the two total prostheses explain the observed changes in the PFF and show how the mechanics of the patellofemoral joint depend upon the kinematics of the tibiofemoral articulation. [Br] 1998;80-B:900-6. J Bone Joint Surg Received 16 October 1997; Accepted after revision 4 June 1998Patellofemoral problems are a common cause of failure after total knee replacement (TKR). Patellar resurfacing implants have often shown loosening or wear of their polyethylene surfaces 1,2 and large increases in anterior patellar strain have been reported after TKR, 3,4 suggesting that joint replacement may have an adverse effect on the mechanics of the extensor mechanism of the knee. We have devised a non-invasive method for measuring the patellofemoral force in a cadaver knee subjected to lifelike loads in a laboratory rig. 5 We now describe the use of that technique to measure changes in the magnitude of the patellofemoral force after the implantation of three designs of knee prosthesis into cadaver joints. Materials and Methods Non-invasive measurement of the patellofemoral force.Three forces act on the patella in the sagittal plane (Fig. 1a). The quadriceps tendon force (QTF) and the patellar tendon force (PTF) are tensile; the patellofemoral force (PFF) is compressive. Equilibrium requires that, if only these three forces act on the patella, they must be coplanar and concurrent at the centre of force of the patella (P). In principle, our method of measurement of the PFF is to replace it with a measured tensile force (TF), applied at point P through a cable attached to the anterior aspect of the bone (Fig. 1b). The tension in the cable is increased until patellar lift-off occurs, at which point TF is deemed to have replaced PFF exactly (Fig. 1c). A detailed description of the testing rig, the method of determining the centre of pressure of the patella and the direction and magnitude of PFF have been published previously. 5Experimental procedure. Eight fresh human cadaver knees were taken at post mortem and quick frozen to -20°C. Immediately before testing each knee was thawed to ro...

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“…Researchers have used ''in vitro'' (cadavers), (Fukubayashi et al, 1982;Goldberg and Henderson, 1980;Hsieh and Walker, 1976;Mahoney et al, 1994;Markolf et al, 1976Markolf et al, , 1979Muller, 1983;O'Connor et al, 1990;Singerman et al, 1994) noninvasive (gait laboratories), (Andriacchi et al, 1986(Andriacchi et al, , 1994Andriacchi, 1993;Draganich et al, 1987;Lafortune et al, 1992;Murphy et al, 1995;Wilson et al, 1996) and in vivo (roentgen stereophotogrammetry and fluoroscopy) (Chao, 1980;Dennis et al, 1998a,b. Kharrholm et al, 1994Nilsson et al, 1991;Sarojak, 1998;Stiehl et al, 1995Stiehl et al, , 1997 approaches to assess human knee motion.…”

Section: Introductionmentioning

confidence: 97%