Biomechanical analysis of Brostrom versus Brostrom-Gould lateral ankle instability repairs.

BACKGROUND: The traditional Brostrom repair and the modified Brostrom-Gould repair are 2 historically reliable procedures used to address lateral ankle instability. The purpose of this study was to evaluate the biomechanical stability conferred by the Brostrom repair as compared to the Brostrom-Gould modification in an unstable cadaveric ankle model.

METHODS: A total of 10 cadaveric specimens were placed in a Telos ankle stress apparatus in an anterior-posterior position and then in a lateral position, while a 170 N load was applied to simulate anterior drawer (AD) and talar tilt (TT) tests, respectively. In both circumstances, the ankle was held in 15 degrees of plantarflexion, neutral, and 15 degrees of dorsiflexion, while the movement of the sensors was measured using a video motion analysis system. Measurement of the translation between the talus and tibia in the AD test and the angle between the tibia and talus in the TT test were calculated for specimens in the (1) intact, (2) sectioned (division of the ATFL and CFL), (3) Brostrom repair and (4) Gould modification states.

RESULTS: When compared to both the repaired states and the intact states, the sectioned state demonstrated increased inversion and translation at all ankle positions during TT and AD testing. Furthermore, no significant differences were found between the intact state and either of the repaired states. Finally, no difference in the biomechanical stability could be identified between the traditional Brostrom repair and the modified Brostrom-Gould procedure.

CONCLUSIONS: Our findings indicate that there is no significant biomechanical difference in initial ankle stability conferred by augmenting the traditional Brostrom repair with the Gould modification in this time-zero cadaveric model.

CLINICAL RELEVANCE: These data suggest that the additional reinforcement of an ankle's lateral ligament complex repair of the ankle with the inferior extensor retinaculum may be marginal at the time of surgery.