Comparison of biomechanics of common compression plate and locking plate fixation for middle and lower complex humeral shaft fracture in the elderly

Zhao Feng-feng

doi:10.3969/j.issn.2095-4344.2016.26.017

Abstract：BACKGROUND:The lower and middle humeral shaft fractures are common upper limb fractures. Incidence rate and recurrence rate were high in the elderly population. However, there is a lack of a method with ideal curative effect. OBJECTIVE:To compare andanalyze the biomechanical differences between common compression plate and locking plate fixation in the repair of middle and lower complex humeral shaft fracture in the elderly. METHODS:30 pairs of antiseptic elderly humerus specimens were selected to make models of middle and lower humeral shaft fracture. Two humeri from the same individual were randomly assigned to two groups, and subjected to locking plate and common compression plate fixation. Experimental mechanics models were used to determine displacement and torsion angle under compression, bending and torsion. Data were analyzed and compared between the two groups. RESULTS AND CONCLUSION:(1) After exclusion of relevant factors, specimens with high bone density and excelent quality were selected from al specimens. (2) Under axial load of 500N, the bending load of 7.0N?m and torsional load of 3N?m or less, the strain was smaler in locking plate group than in common compression plate group under compression, bending and torsion (P< 0.05). Relative displacement under the above loading was smaler in locking plate group than in common compression plate group (P< 0.05). (3) Above data suggested that locking plate has good compressive, flexural and torsional rigidity, can ensure the stability and integrity of the fracture connection.