Document Detail

Biomechanical assays for the study of the effects of hip prostheses: application to the reconstruction of bone defects with femoral allografts.
MedLine Citation:
PMID:  23275030     Owner:  NLM     Status:  Publisher    
There is a need to study and validate the mechanical behavior of the bone-implant total hip prosthesis and the treatment of its complications with experimental studies due to the limitations showed by numerical methods. Epoxy resin replicas of a femur (stereolithography) and a mechanical validation were performed. We studied three cases: intact femur (Case 1); non-defective femur with non-cemented LD primary stem (Case 2); and femur with a cavitary defect, short cemented stem over an impacted allograft (Case 3). The test pieces were connected to 7 strain gauges. Three assays per piece were carried out with a vertical and oblique load (load-unload curves after a sequence between 0 and 145.9 N). We measured the k coefficient (distance from the natural state of the strains) and stability of the stem (flexion-compression by strain gauges 1, 2, 5, and 7 and transversal lengthening by strain gauges 3, 4, and 6). Results of the strain gauge analysis revealed linearity of results in all cases, and more so in load than in unload. Gauge 7 (proximal) revealed shortening in all cases. Gauges 2 and 5 provided qualitatively similar data due to a significant increase in rigidity. K coefficients were obtained with a nonsignificant difference when each of the test pieces was compared with Case 2. The results were reproducible in all 7 gauges. Observation of the load-unload curves in all the test pieces assayed shows that there are no variations in the pattern of behavior (when comparing the stability of a primary stem and a stem in the simulated reconstructed femoral defect. If these reconstructions are considered theoretically appropriate for giving primary stability to the stem-a sine qua non for the success of replacement surgery-then our study is novel.
Alberto Francés; Rafael Claramunt; Juan-Luis Cebrian; Fernando Marco; Yaiza Lópiz; Ramon Muiña Rullanç; Antonio Ros; Luis López-Durán
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-12-30
Journal Detail:
Title:  Musculoskeletal surgery     Volume:  -     ISSN:  2035-5114     ISO Abbreviation:  Musculoskelet Surg     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-12-31     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101498346     Medline TA:  Musculoskelet Surg     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Servicio de Cirugía Ortopédica y Traumatología, Hospital Clínico San Carlos, C/Río Pisuerga n° 16, Boadilla del Monte, 28669, Madrid, Spain,
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