Biomechanical Analysis of Peri-acetabular Lesions to Predict Pathologic Fracture
Main Article Content
Abstract
The classification and treatment of pathologic peri-acetabular lesions was initially described by Harrington5. However, the ability to predict impending pathologic fractures is difficult. Proposed treatment in the literature has included external beam radiation and cemented total hip arthroplasty. Based on a cadaveric biomechanical model, our goal is to delineate the risk of pathologic fracture in contained Harrington class 1 lesions.
Eight paired hemi-pelvises were utilized to create peri-acetabular defects with its paired side to serve as a control. Volumetric measurements were taken via computed tomography then converted to a percentage of the peri-acetabular volume. Each paired specimen was axially loaded to catastrophic failure via Material Testing System (MTS, Minneapolis, MN).
The results demonstrate that larger (>40%) contained peri-acetabular defects can support significant less load than an intact acetabulum. Smaller defects did not fail at significantly less load, and their location of failure was not consistent. Though the load to failure was significantly less than the intact controls, the levels were found to be nearly 2.5 times the normal physiologic loads that the hip encounters at its peak3. These results do indicate that volumetric measurements via CT scan is a simple technique, and its clinical relevance as a tool to predict pathologic fracture of peri-acetabular lesions must be further investigated.
Article Details
The Medical Research Archives grants authors the right to publish and reproduce the unrevised contribution in whole or in part at any time and in any form for any scholarly non-commercial purpose with the condition that all publications of the contribution include a full citation to the journal as published by the Medical Research Archives.
References
2. Assessment of fracture risk and its application to screening for post-menopausal osteoporosis. Geneva: World Health Organization; 1994, Technical Report Series, No. 843.
3. Bergmann G, Deuretzbacher G, Heller M, et al. Hip contact forces and gait patterns from routine activities. J Biomechanics 2001;34:859-71
4. Dalstra M, Huiskes R. Load Transfer across the pelvic bone. J Biomechanics 1995;28:714-24
5. Harrington KD. The management of acetabular insufficiency secondary to metastatic malignant disease. JBJS 1981;63A:653-64
6. Levine RG, Renard R, Behrens FF, et al. Biomechanical consequences of secondary congruence after both-column acetabular fracture. J. Orthop Trauma 2002:2:87-91
7. Marco RA, Dhiren SS, Boland PJ, et al. Functional and oncological outcome of acetabular reconstruction for the treatment of metastatic disease. JBJS 2000;82A:642-51
8. Olson SA, Matta JM. The computerized tomography subchondral arc: A new method of assessing acetabular articular continuity after fracture ( a preliminary report). J Orthop Trauma 1993:7:402-13
9. Patterson FR, Peabody TD. Operative management of metastases to the pelvis and acetabulum. OCNA 2000;31:623-31
10. Vena VE, Hsu J, Rosier RN, et al. Pelvis reconstruction for severe periacetabular metastatic disease. CORR 1999;362:171-80