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Function of the screw home mechanism following bone-tendon bone reconstructive surgery

1 May 1995


The purpose of this study was to determine the number of patients who had a properly functioning SHM, in the open and closed chain positions, following an ACL reconstructive surgery. A second purpose was to determine the intra-tester reliability of the Helfet test, for measuring presence and amount of external tibial rotation at terminal extension of the knee. Terminal knee extension (using a goniometer) and tibial rotation (using the Modified Helfet test) measurements were taken in the standing and supine positions, of the involved and non-involved extremities of 13 subjects. The subjects ranged in age from 17 to 45 years of age (mean = 30), and were between 2 months and 14 months (mean = 7 months) post ACL reconstructive surgery. No significant differences in amount of extension or tibial rotation were found between supine and standing positions. however, significant differences were found between the amount of external tibial rotation of the involved extremity when compared to the non-involved extremity (p= .0001), and in the degree of extension of the involved extremity as compared to the non-involved extremity (p=.0002). In both cases the ranges were limited to the involved extremity.

Test-retest measurement of knee extension using a goniometer was found to be reliable (ICC= .76). The Modified Helfet test was found to be unreliable (ICC= .52) for measuring the amount of external tibial rotation.


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