All-inside arthroscopic modified Brostrom operation for chronic ankle instability: a biomechanical study

Abstract

The all-inside arthroscopic modified Brostrom operation has been developed for lateral ankle instability. We compared the biomechanical parameters of the all-inside arthroscopic procedure to the open modified Brostrom operation. Eleven matched pairs of human cadaver specimens [average age 71.5 (range 58-98) years] were subject to the arthroscopic modified Brostrom operation using a suture anchor and the open modified Brostrom operation. The ligaments were loaded cyclically 20 times and then tested to failure. Torque to failure, degrees to failure, and stiffness were measured. A matched-pair analysis was performed. There was no significant difference in torque to failure between the open and arthroscopic modified Brostrom operation (19.9 +/- A 8.9 vs. 23.3 +/- A 12.1 Nm, n.s). The degrees to failure did not differ significantly between the open and arthroscopic modified Brostrom operations (46.8 +/- A 9.9A degrees vs. 46.7 +/- A 7.6A degrees, n.s). The working construct stiffness (or stiffness to failure) was no significant difference in the two groups (0.438 +/- A 0.21 vs. 0.487 +/- A 0.268 Nm/deg for the open and arthroscopic modified Brostrom operations, respectively, n.s). The all-inside arthroscopic modified Brostrom operation and the open modified Brostrom operation resulted in no significantly different torque to failure, degrees to failure, and working construct stiffness with no significant differences (n.s, n.s, and n.s, respectively). Our results indicate that the arthroscopic modified Brostrom operation is a reasonable alternative procedure for chronic ankle instability.