Evaluation of Porosity in Cylindrical Bone Cement Specimen Using Image Analysis System

Song, Joo Hyoun; Kwon, Soon Yong; Koh, Hae Seok; Lee, Han Yong; Lee, Ju Yup; Jeong, Jin Young; Kang, Yong Koo; Song, Ho Wook

Abstract

PURPOSE
The porosity of the bone cement is the most important cause of fatigue failure, the most common mode of failure of bone cement using widely in arthroplasty. It is important to evaluate the porosity of bone cement for improvement or development of bone cement, but the conventional 'stain, 'cut, and 'polish, manual method takes long time and efforts. So it is necessary to develop a new technique for evaluation of porosity of bone cement. We tried a technique using computer image analysis system to evaluate the porosity of bone cement specimen and assess efficacy of the method. Simultaneously we evaluated the relationship between the porosity of bone cement and fatigue failure. MATERIAL AND METHODS: We made 59, 2.5inch-length bone cement specimens(30 Simplex P, 29 Palacos R) using Simplex P and Palaces R which are widely using in clinical situation and checked radiogram using mammography film. After scanning the mammography film, we measured the porosity of the bone cement specimens using NIH(National Institute for Health) Image 1.6 version image analysis program. We also, measured the porosity of the bone cement specimens with conventional 'stain','cut' and 'polish' method, after then compared the results of two methods. Simultaneously, we evaluated the relationship between porosity & fatigue failure by loading 9.0, 10.0, 12.5 and 15.0 MPa load with frequency of 10Hz to the bone cement specimens under the physiologic condition.
RESULTS
The coefficient of relation of simplex P and palaces R was 0.729 and 0.713 respectively, so there was high relationship between the image analysis system method and conventional one. It was easy and took shorter time to measure the porosity of bone cement specimens with image analysis system. There was high correlation between cement porosity and fatigue failure, regardless of level of load.
CONCLUSION
It was very easy and fast to measure the porosity of the bone cement specimens with image analysis system and there was high correlation between cement porosity and fatigue failure.