Biomedical subjects

R Nagamine

Publications and source records attributed to R Nagamine.

21 records · Page 2Linked to original sources

PubMed1995

Effect of rotational malposition of the femoral component on knee stability kinematics after total knee arthroplasty.

Excessive external rotation of the femoral component can cause an abnormally tight popliteus tendon complex, which induces loss of rotational laxity of the knee in the late phase of knee flexion after total knee arthroplasty. This study evaluated the effect of popliteus tendon release on rotational and varus-valgus laxity of implanted knees with an excessively externally rotated femoral component. Rotational and varus-valgus laxity was measured with a knee kinematics testing device before and after total knee arthroplasty. External rotational positions of the femoral component of 5 degrees and 8 degrees were compared, and the effects of popliteus tendon release on rotational and varus-valgus laxity were evaluated. To further investigate this question, the effect of a conforming articular design was compared with that of a flat tibial surface. External rotational position of 5 degrees did not change rotational or varus-valgus laxity of the knee. With an 8 degrees external rotational position, however, external rotational laxity significantly decreased in knees with a conforming surface at angles of 30 degrees, 45 degrees, 60 degrees, and 90 degrees. After popliteus tendon release, external rotational laxity significantly improved at 90 degrees flexion and was identical to that of the normal knee. Internal rotational range was similar before and after popliteus tendon release. Popliteus tendon release did not affect the varus-valgus laxity (stability) with either articular surface.

Biophysical Phenomena↗

PubMed1994

Patellar tracking after total knee arthroplasty. The effect of tibial tray malrotation and articular surface configuration.

The effect of total knee arthroplasty (TKA) with neutrally aligned and malrotated tibial trays was studied in five fresh anatomic specimen knees. Patellar shift, tilt, and rotation, and the rotational position of the tibia were measured in normal knees and after TKA with the Ortholoc Modular knee system. Both semiconstrained and unconstrained articular surfaces were assessed in the neutral position and at anatomic, 15 degrees internal, and 15 degrees external rotation of the tibial tray. After TKA, the patellae shifted slightly medially in the early phase of knee flexion because the anterior lateral flange of the femoral component was longer than the lateral trochlea of the femur and because the tibia rotated internally. The raised lateral flange on the femoral component tilted the patella medially at full extension after TKA. The semiconstrained tray allowed minimal tibial rotation because of its articular configuration. As much as 15 degrees malrotation of the unconstrained tibial tray did not affect patellar tracking. The semiconstrained tibial tray in the neutral position had almost the same patellar tracking as the unconstrained tray, but at 15 degrees external rotation, the semiconstrained tray internally rotated the tibia, leading to medial shift of the patella. Although 15 degrees internal rotation caused external rotation of the tibia, the patella did not shift as much laterally, despite the increase in the Q angle.

Biomechanical Phenomena↗

PubMedDate not supplied

Factors affecting depression and anxiety in female Japanese patients with rheumatoid arthritis.

OBJECTIVE: In this study, we attempted to identify which background factors were the most important indicators regarding such psychological problems as depression and anxiety in female rheumatoid arthritis (RA) patients. METHODS: Among female RA patients aged 20 and older, who visited the outpatient clinic, and who met the Revised Criteria of the American Rheumatism Association for RA (ARA1987), 101 Class I and II patients were selected as subjects for the present study. Specially designed questionnaires and psychological tests were given to those subjects who had given their written consent for such testing, and a stepwise multiple logistic regression analysis was carried out on the 85 patients who returned all written forms. Those factors affecting psychological problems at a significance level of 5% or less were identified. RESULTS: It was shown that among sociodemographic factors, "a decrease in the frequency of going out socially after having RA" and "a higher education" worked as significantly associated variables for depression, while "a decrease in the number of friends after having RA" served as a significantly associated variable for trait anxiety. Significantly associated variables for state anxiety included "a decrease in the frequency of going out socially after having RA" and "a willingness to join an RA study group". CONCLUSION: The present study demonstrated that factors related to social interactions were significantly associated with depression and anxiety in Class I and II female RA outpatients.

Adult↗