Interface Stability on Insufficient Coverage of Non-cemented Acetabular Cup with Screw Fixations / 대한정형외과학회잡지

PURPOSE: To analyze the effects of various amount of peripheral defect of the acetabulum in terms of the stability of the acetabular cup with screw fixation. MATERIALS AND METHODS: The porous coated acetabular cup of Trilogy was press-fitted with 3 screw fixations after 2 mm undersized reaming into the distal part of 100 bovine femurs, but with insufficient peripheral coverage of 0%, 5%, 10%, 15% and 20% respectively. The micromotions of the acetabular cups were measured under the axial loads of 50, 100, 150, 200, 250, and 300 Kp, and torques were measured at 1degrees to 5degrees of cup rotation under applied rotational force in 10 specimens in each of five groups. RESULTS: The micromotion between the cup and bone interface increased proportionally with peripheral coverage insufficiency and the torque values in the five groups increased in proportion to the rotation degree and were inversely proportinal peripheral coverage insufficiency. CONCLUSION: 15% or less coverage insufficiency of the acetabular cup may be acceptable as the average micromotion is less than 150micrometa and compatible with biologic fixations.

Non-union of Scaphoid Fracture: Comparison according to the Method of Operation / 대한정형외과학회잡지

PURPOSE: To evaluate the operative methods which can induce an early uinon and better functional outcome in the non-union of scaphoid fracture. MATERIALS AND METHODS: We evaluated 16 patients (16 cases) who had taken autogenous iliac bone graft and internal fixation with compression screws or K-wires for the treatment of scaphoid fracture non-union. The average follow-up period was 21.1 months. Anteroposterior, lateral and scaphoid views were taken at last follow-up for the purpose of evaluating radiological results. The ranges of wrist motion and grip strength were measured to evaluate functional results, and the patient's subjective responses were also evaluated. RESULTS: Radiological unions were obtained in 15 cases (93.8%) with the average time to union at 3.2 months (2~7 months) . Radio-ulnar deviation arcs and grip strength were better in the cases fixated with compression screws than K-wires. Twelve patients (75%) showed satisfactory subjective results at the time of last follow up. CONCLUSION: The iliac bone graft is a good treatment method for scaphoid fracture non-union. We think that the compression screw, which has better stability, is a more profitable fixation device for improved functional recovery.