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Papers by Kristen Hovinga

Research paper thumbnail of Using Force and Kinematic Driven Finite Element Models to Analyze Contact Pressure Distributions on the Tibial Plateau

ASME 2007 Summer Bioengineering Conference, 2007

ABSTRACT Finite element (FE) models have become an effective tool in studying soft tissue behavio... more ABSTRACT Finite element (FE) models have become an effective tool in studying soft tissue behavior in the knee joint, including meniscal translation and deformation, as well as articular cartilage contact [1–2]. These models are also useful in osteoarthritis research and implant design [3–4]. Our group has previously used a kinematic-driven FE analysis to study the effect of weightbearing on the load distribution of tibio-menisco-femoral contact using MR imaging [5].

Research paper thumbnail of Anatomic variations between Japanese and Caucasian populations in the healthy young adult knee joint

Journal of Orthopaedic Research, 2009

Our objective was to characterize variations in mechanical knee alignment, tibial torsion, tibial... more Our objective was to characterize variations in mechanical knee alignment, tibial torsion, tibial width, and ACL laxity measurements between Japanese and Caucasian populations in the healthy, young adult knee joint. Seventy young adult subjects participated in this study, including 23 Japanese and 47 Caucasian subjects. Coronal magnetic resonance images of the hip, knee, and ankle were acquired for analysis. Japanese subjects had a significantly higher (p = 0.04) varus alignment (1.64 +/- 0.43 degrees standard error) than Caucasians (0.55 +/- 0.33 degrees), while women exhibited a more valgus alignment (0.16 +/- 0.52 degrees) than men (0.94 +/- 0.42 degrees, p = 0.04). Significant differences were found in tibial torsion and ACL laxity (p < 0.01) between ethnicities, with Japanese exhibiting lower tibial torsion (33.4 +/- 10.0 degrees) and higher ACL laxity (7.5 +/- 0.4 mm) measurements compared to Caucasians (38.9 +/- 9.5 degrees and 5.7 +/- 0.3 mm, respectively). Significant differences between genders were found in hip-knee-ankle alignment (p = 0.04), tibial width (p < 0.0001), and ACL laxity (p < 0.01) measurements. Measurements were reliable between observers and for repeated positioning. Our study provides new insight into anatomical and geometric differences in the knee joint between Japanese and Caucasians, as well as between females and males. Further consideration of these results may improve development of implants to accommodate for these differences, and understanding of characteristics leading to increased prevalence of knee OA in certain populations. The use of magnetic resonance imaging to obtain these measurements also allows soft tissue structure characterization without exposure to ionizing radiation.

Research paper thumbnail of Magnetic resonance image analysis of meniscal translation and tibio-menisco-femoral contact in deep knee flexion

Journal of Orthopaedic Research, 2008

The purpose of this study was to clarify meniscal displacement and cartilage-meniscus contact beh... more The purpose of this study was to clarify meniscal displacement and cartilage-meniscus contact behavior in a full extension position and a deep knee flexion position. We also studied whether the meniscal translation pattern correlated with the tibiofemoral cartilage contact kinematics. Magnetic resonance (MR) images were acquired at both positions for 10 subjects using a conventional MR scanner. Subjects achieved a flexion angle averaging 1398 AE 38. Both medial and lateral menisci translated posteriorly on the tibial plateau during deep knee flexion. The posterior translation of the lateral meniscus (8.2 AE 3.2 mm) was greater than the medial (3.3 AE 1.5 mm). This difference was correlated with the difference in tibiofemoral contact kinematics between medial and lateral compartments. Contact areas in deep flexion were approximately 75% those at full extension. In addition, the percentage of area in contact with menisci increased significantly due to deep flexion. Our results related to meniscal translation and tibio-menisco-femoral contact in deep knee flexion, in combination with information about force and pressure in the knee, may lead to a better understanding of the mechanism of meniscal degeneration and osteoarthritis associated with prolonged kneeling and squatting.ß

Research paper thumbnail of In Vivo Normal Knee Kinematics: Is Ethnicity or Gender an Influencing Factor?

Clinical Orthopaedics and Related Research®, 2011

Background In vivo studies have suggested Caucasians achieve lower average knee flexion than non-... more Background In vivo studies have suggested Caucasians achieve lower average knee flexion than non-Western populations. Some previous studies have also suggested gender may influence condylar AP translation and axial rotation, while others report an absence of such an influence. Questions/purposes We determined whether different ethnic and gender groups residing in the United States had different knee translations and rotations. Methods Three-dimensional knee rotations and translations were determined for 72 healthy subjects (24 Caucasian men, 24 Caucasian women, 13 Japanese men, 11 Japanese women) from full extension to maximum flexion using a fluoroscopic technique, under in vivo, weightbearing conditions. Results Although we observed substantial variability in all groups, small differences between groups were found, especially in deep flexion. Japanese women and men and Caucasian women achieved higher maximum flexion (153°, 151°, and 152°, respectively) than Caucasian men (146°). External rotation was higher for these three groups than for Caucasian men. The medial condyle remained more anterior for Caucasian women and all Japanese subjects than for Caucasian men, possibly leading to greater axial rotation and flexion, observed for these three groups.

Research paper thumbnail of Using Force and Kinematic Driven Finite Element Models to Analyze Contact Pressure Distributions on the Tibial Plateau

ASME 2007 Summer Bioengineering Conference, 2007

ABSTRACT Finite element (FE) models have become an effective tool in studying soft tissue behavio... more ABSTRACT Finite element (FE) models have become an effective tool in studying soft tissue behavior in the knee joint, including meniscal translation and deformation, as well as articular cartilage contact [1–2]. These models are also useful in osteoarthritis research and implant design [3–4]. Our group has previously used a kinematic-driven FE analysis to study the effect of weightbearing on the load distribution of tibio-menisco-femoral contact using MR imaging [5].

Research paper thumbnail of Anatomic variations between Japanese and Caucasian populations in the healthy young adult knee joint

Journal of Orthopaedic Research, 2009

Our objective was to characterize variations in mechanical knee alignment, tibial torsion, tibial... more Our objective was to characterize variations in mechanical knee alignment, tibial torsion, tibial width, and ACL laxity measurements between Japanese and Caucasian populations in the healthy, young adult knee joint. Seventy young adult subjects participated in this study, including 23 Japanese and 47 Caucasian subjects. Coronal magnetic resonance images of the hip, knee, and ankle were acquired for analysis. Japanese subjects had a significantly higher (p = 0.04) varus alignment (1.64 +/- 0.43 degrees standard error) than Caucasians (0.55 +/- 0.33 degrees), while women exhibited a more valgus alignment (0.16 +/- 0.52 degrees) than men (0.94 +/- 0.42 degrees, p = 0.04). Significant differences were found in tibial torsion and ACL laxity (p < 0.01) between ethnicities, with Japanese exhibiting lower tibial torsion (33.4 +/- 10.0 degrees) and higher ACL laxity (7.5 +/- 0.4 mm) measurements compared to Caucasians (38.9 +/- 9.5 degrees and 5.7 +/- 0.3 mm, respectively). Significant differences between genders were found in hip-knee-ankle alignment (p = 0.04), tibial width (p < 0.0001), and ACL laxity (p < 0.01) measurements. Measurements were reliable between observers and for repeated positioning. Our study provides new insight into anatomical and geometric differences in the knee joint between Japanese and Caucasians, as well as between females and males. Further consideration of these results may improve development of implants to accommodate for these differences, and understanding of characteristics leading to increased prevalence of knee OA in certain populations. The use of magnetic resonance imaging to obtain these measurements also allows soft tissue structure characterization without exposure to ionizing radiation.

Research paper thumbnail of Magnetic resonance image analysis of meniscal translation and tibio-menisco-femoral contact in deep knee flexion

Journal of Orthopaedic Research, 2008

The purpose of this study was to clarify meniscal displacement and cartilage-meniscus contact beh... more The purpose of this study was to clarify meniscal displacement and cartilage-meniscus contact behavior in a full extension position and a deep knee flexion position. We also studied whether the meniscal translation pattern correlated with the tibiofemoral cartilage contact kinematics. Magnetic resonance (MR) images were acquired at both positions for 10 subjects using a conventional MR scanner. Subjects achieved a flexion angle averaging 1398 AE 38. Both medial and lateral menisci translated posteriorly on the tibial plateau during deep knee flexion. The posterior translation of the lateral meniscus (8.2 AE 3.2 mm) was greater than the medial (3.3 AE 1.5 mm). This difference was correlated with the difference in tibiofemoral contact kinematics between medial and lateral compartments. Contact areas in deep flexion were approximately 75% those at full extension. In addition, the percentage of area in contact with menisci increased significantly due to deep flexion. Our results related to meniscal translation and tibio-menisco-femoral contact in deep knee flexion, in combination with information about force and pressure in the knee, may lead to a better understanding of the mechanism of meniscal degeneration and osteoarthritis associated with prolonged kneeling and squatting.ß

Research paper thumbnail of In Vivo Normal Knee Kinematics: Is Ethnicity or Gender an Influencing Factor?

Clinical Orthopaedics and Related Research®, 2011

Background In vivo studies have suggested Caucasians achieve lower average knee flexion than non-... more Background In vivo studies have suggested Caucasians achieve lower average knee flexion than non-Western populations. Some previous studies have also suggested gender may influence condylar AP translation and axial rotation, while others report an absence of such an influence. Questions/purposes We determined whether different ethnic and gender groups residing in the United States had different knee translations and rotations. Methods Three-dimensional knee rotations and translations were determined for 72 healthy subjects (24 Caucasian men, 24 Caucasian women, 13 Japanese men, 11 Japanese women) from full extension to maximum flexion using a fluoroscopic technique, under in vivo, weightbearing conditions. Results Although we observed substantial variability in all groups, small differences between groups were found, especially in deep flexion. Japanese women and men and Caucasian women achieved higher maximum flexion (153°, 151°, and 152°, respectively) than Caucasian men (146°). External rotation was higher for these three groups than for Caucasian men. The medial condyle remained more anterior for Caucasian women and all Japanese subjects than for Caucasian men, possibly leading to greater axial rotation and flexion, observed for these three groups.