Osamu Tanifuji

Niigata University, Niahi-niigata, Niigata, Japan

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Publications (8)13.7 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of this study was to investigate the hypothesis that a medial unicompartmental knee arthroplasty might restore the functional flexion axis of a knee to normal. The flexion axis can be indirectly identified by tracking the vertical translation of anatomic landmarks that basically move around the flexion axis during a knee motion. If a unicompartmental knee could help restore the normal flexion axis, the anatomic landmarks after the arthroplasty would show the vertical translation similar to those of normal knees during a knee flexion.
    Knee Surgery Sports Traumatology Arthroscopy 09/2014; · 2.68 Impact Factor
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    ABSTRACT: The functional flexion axis (FFA) is the principal axis around which the knee moves and thus, by definition, does not move in vertical displacement relative to the tibia. The transepicondylar axis (TEA) has been reported to coincide with the FFA. If that is not true, the TEA should show vertical displacement during motion, and this hypothesis was investigated. Three-dimensional knee kinematics of 20 healthy volunteers were determined during a squatting motion via a 3-dimensional to 2-dimensional image registration technique by calculating the vertical displacement of the clinical epicondylar axis (CEA) through the full range of motion. From 0° to 90° knee flexion, the average vertical displacement of the lateral end of the CEA was <3 mm, whereas that of the medial end was large (7.6 mm). The large vertical displacement of the medial end of the CEA suggests that the CEA is not the FFA. This finding implies that the CEA may not be an appropriate axis for a TKA prosthesis having a "single radius" design. Level IV.
    Journal of Orthopaedic Science 02/2014; · 0.96 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: It is common to assert that restoration of normal knee kinematics is essential for the best functional result after knee arthroplasty. Previous studies using the progression of the geometric centre axis have suggested that kinematics after unicompartmental arthroplasty is markedly different from the normal. For this study, the transepicondylar axis was used because this axis is closer to the flexion axis and should be a better reference for motion. The following hypothesis was tested: the transepicondylar axis would again show that the postoperative kinematics does not restore normal motion and is closer to that before replacement. Seventeen osteoarthritic knees were tested before and after unicompartmental arthroplasty using a three-dimensional to two-dimensional registration technique tracking the transepicondylar axis to calculate translation and rotation of this axis. Results were compared for the seventeen knees before and after arthroplasty and were compared to the normal knee as measured in our previous study. Similar motion patterns in the pre- and postoperative knees were shown but both the pre- and postoperative motion were markedly different from the normal knee. This result supported our hypothesis. The clinical relevance is that medial unicompartmental arthroplasty cannot restore the motion of the knee to normal in the living knee. Therefore, it would be expected that the patient for unicompartmental knee might not feel normal. It may not be possible depending on ligaments alone to restore the knee to normal, and the changes in the articular shapes and the surgical procedure may also be necessary. LEVEL OF EVIDENCE: IV.
    Knee Surgery Sports Traumatology Arthroscopy 11/2013; · 2.68 Impact Factor
  • Osamu Tanifuji, John David Blaha, Shin Kai
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    ABSTRACT: BACKGROUND: The quadriceps is the primary extensor of the knee. Its vector, which is perpendicular to the flexion axis of the knee, is important in understanding knee function and properly aligning total knee components. Three-dimensional (3-D) imaging enables evaluation using a 3-D model of each quadriceps component. QUESTIONS/PURPOSES: We calculated the direction and magnitude of the quadriceps vector (QV) and the precision of the measurement, and asked whether the QV bears a constant relationship to the femur and is aligned with an anatomically based axis on the femur. METHODS: Using CT data of 14 subjects, we created a 3-D solid model of each quadriceps muscle component. Vectors (3-D direction and length) for each quadriceps component were determined using principal component analysis for muscle direction and volume for magnitude; vector addition established the directional vector of the combined muscle. The combined vector originating in the center of the patella was compared with the shaft, mechanical, and spherical (center femoral head to center medial side of the knee) axes. RESULTS: The QV passed from the patella center proximally crossing the femoral neck between the femoral head and greater trochanter and was most closely aligned with the spherical axis. CONCLUSIONS: The QV axis may be an important reference for alignment of total knee components. CLINICAL RELEVANCE: The spherical axis can be used in aligning total knee components to the flexion axis of the knee.
    Clinical Orthopaedics and Related Research 12/2012; · 2.79 Impact Factor
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    ABSTRACT: BACKGROUND: Pre- and postoperative knee kinematics in unicompartmental knee arthroplasty (UKA) can be theoretically related to clinical outcome and longevity after UKA with regard to ligament function and the degree of arthritic changes. However, the preoperative knee kinematics of patients indicated for UKA remain to be elucidated, and it is also unclear whether the preoperative kinematics can be maintained by the UKA procedure. The objective of this study was to examine the in vivo pre- and postoperative three-dimensional knee kinematics in UKA while referencing the normal knee kinematics reported in our previous study. METHODS: We analyzed the knee kinematics in 17 knees (14 patients) undergoing UKA via a three-dimensional to two-dimensional registration technique employing femoral condylar translation and femoral axial rotation. The pre- and postoperative knee kinematics during squat motion were evaluated in the same subjects, employing consistent evaluation parameters. RESULTS: On average, both pre- and postoperative knee kinematics in the range 10-100° of knee flexion demonstrated near-consistent femoral external rotation and anterior translation of the medial condyle and posterior translation of the lateral condyle. However, the mean femoral external rotation angle and the posterior translation of the lateral condyle postoperatively were significantly smaller than the values observed preoperatively. DISCUSSION: Although the patterns of preoperative knee motion were similar to those seen in normal knees, the magnitude of this motion varied widely between patients, so it was not necessarily representative of normal knees. These variations may be due to the varying degrees of arthritic changes caused by osteoarthritis. Although the patterns of knee kinematics were largely maintained by the UKA procedure, the causes of the significant reductions in the magnitude of motion upon performing the UKA procedure should be investigated in subsequent studies with a larger number of patients.
    Journal of Orthopaedic Science 11/2012; · 0.96 Impact Factor
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    ABSTRACT: PURPOSE: The transepicondylar axis (TEA) has been used as a flexion axis of the knee and a reference of the rotational alignment of the femoral component. However, no study has showed dynamic normal knee kinematics employing TEA as the evaluation parameter throughout the full range of motion in vivo. The purpose of this study was to analyze dynamic kinematics of the normal knee through the full range of motion via the 3-dimensional to 2-dimensional registration technique employing TEA as the evaluation parameter. METHODS: Dynamic motion of the right knee was analyzed in 20 healthy volunteers (10 female, 10 male; mean age 37.2 years). Knee motion was observed as subjects squatted from standing with knee fully extended to maximum flexion. The following parameters were determined: (1) Anteroposterior translations of the medial and lateral ends of the TEA; and (2) changes in the angle of the TEA on the tibial axial plane (rotation angle). RESULTS: The medial end of the TEA demonstrated anterior translation (3.6 ± 3.0 mm) from full extension to 30° flexion and demonstrated posterior translation (18.1 ± 3.7 mm) after 30°, while the lateral end of the TEA demonstrated consistent posterior translation (31.1 ± 7.3 mm) throughout knee flexion. All subjects exhibited femoral external rotation (16.9 ± 6.2°) relative to the tibia throughout knee flexion. CONCLUSION: Compared to previously used parameters, the TEA showed bicondylar posterior translation from early flexion phase. These results provide control data for dynamic kinematic analyses of pathologic knees in the future and will be useful in the design of total knee prostheses.
    Knee Surgery Sports Traumatology Arthroscopy 04/2012; · 2.68 Impact Factor
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    ABSTRACT: Analysis of the movement of anatomically defined reference axes at the femoral condyles relative to the tibia is appropriate for evaluating knee kinematics. However, such parameters have been previously employed only in studies utilizing stop-motion techniques. The purpose of this study was to evaluate in vivo dynamic kinematics for full range of motion in normal knees using the three-dimensional to two-dimensional registration technique and to compare them with previously reported normal knee kinematics obtained via stop-motion techniques. Dynamic motion of the right knee was analyzed in 20 healthy volunteers (10 female, 10 male; mean age 37.2 years). Knee motion was observed when subjects squatted from standing with the knee fully extended to maximum flexion. We determined the following parameters: (1) changes to angles of the geometric center axis (GCA) on the tibial axial plane (rotation angle); (2) anteroposterior translations of the medial and lateral ends of the GCA; and (3) motion patterns in each phase during knee flexion. All subjects exhibited femoral external rotation (26.1°) relative to the tibia throughout knee flexion. The medial femoral condyle demonstrated anterior translation (5.5 mm) from full extension to 100° flexion, and demonstrated posterior translation (3.9 mm) after 100°, while the lateral femoral condyle demonstrated consistent posterior translation (15.6 mm) throughout knee flexion. All subjects showed medial pivot motion from full extension to nearly 120° flexion. From 120° flexion, bicondylar rollback motion was observed. Although the behavior of the medial femoral condyle in our analysis differed somewhat from that seen in previous cadaver studies, the results obtained using dynamic analysis were generally equivalent to those obtained in previous studies employing stop-motion techniques. These results provide control data for future dynamic kinematic analyses of pathological knees.
    Journal of Orthopaedic Science 09/2011; 16(6):710-8. · 0.96 Impact Factor
  • J. David Blaha, Osamu Tanifuji
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    ABSTRACT: Selection of an acetabular component for total hip arthroplasty that can achieve initial stability and then remain stable for long-term fixation to occur requires specific implant design features. In this work, the authors describe the stages of implant fixation for cemented and cementless components, identify the key design characteristics of an acetabular component that will ensure stability as bone remodeling or osseointegration occurs, and review the clinical results of various cup designs. The authors recommend an acetabular component that offers good initial fixation, limits migration during the intermediate stage, provides a mechanism for osseointegration, and resists tensile loads.
    Seminars in Arthroplasty 01/2011; 22(2):85-89.

Publication Stats

10 Citations
13.70 Total Impact Points

Institutions

  • 2012
    • Niigata University
      • Department of Regenerative and Transplant Medicine
      Niahi-niigata, Niigata, Japan
  • 2011–2012
    • University of Michigan
      • Department of Orthopaedic Surgery
      Ann Arbor, MI, United States