Axisymmetric Contact Stress analysis of an Artificial Hip Joint of the Conical Fitting Type / 대한정형외과학회잡지

The purpose of this study is to investigate the effect of the ball-cone contact interface variation on the ceramic ball stress which is the dominant factor of the design of the moldular artificial hip joint. A contact stress analysis problem is formulated using the optimization principle and finite element analysis technique on the ball-cone system of three dimensional axi-symmetrical model, Numerical procedure is employed to get the solution for varying angles of cones and angular mismatches between the ball and cone interfaces. There is a fair amount of friction in the interface and included in the analysis model.

Comparative Analysis of Simultaneous and Staged Bilateral Total Knee Arthroplasty / 대한정형외과학회잡지

Between January 1982 and September 1986, at the Department of Orthopaedic Surgery of Kyung Hee University Hospital, 82 total knee arthroplasties were performed in 57 patients. We studied 25 patients (50 Knees) who had been operated by bilateral total knee arthroplasties to compare one stage and two stage operations. The follow-up ranged from 10 months to 5 years and 7 months (average 1 year and 8 months). All operations were performed by one of the authors (D.K.B.), but the follow-up study and the entire medical record were independently evaluated by another authors. The clinical results of preoperative and postoperative assessments and rehabilitation processes are as follows; 1. Group I (10 patients) had both kness replaced by one stage simultaneous operation under same anesthesia, and Group II(15 patients) had replaced by two stage operation at the intervals of 2 weeks. 2. The periods required to do bilateral weight bearing were 10.3 days for Group I, 23.6 days for Group II. 3. Complications in one stage operation was no more than the in two stage operation. 4. The postoperative pain and ROM were not significantly different in both groups. 5. Using the hospital for special surgery rating system, we found the clinical results to be similar in both groups. 6. Comparing to two stage operation, the advantages of one stage operation were shorter operative and tourniquet time, lesser use of antibiotics, reduced medical cost and hospital stay. In conclusion, if patient conditions do not prevent prolonged anesthetic time and surgeons have good surgical techniques, we recommend one stage simultaneous operation in bilateral total knee replacement.