Characterization of plantaris tendon constructs for ankle ligament reconstruction.

BACKGROUND

Many techniques have been described for lateral ligament reconstruction. One frequently overlooked autograft option is the plantaris tendon, potentially due to the paucity of data on its mechanical characteristics. This study examined the structural properties of double and quadruple plantaris tendon constructs.

METHODS

Plantaris tendons were harvested from 35 fresh-frozen human cadaver specimens (mean age, 66 years [range, 43-89 years]; 17 female, 13 male). The tendon ends were sutured in a running locking technique and then woven onto a template board to create double or quadruple graft constructs with a 20-mm functional length. If additional tendon length remained, a single 40-mm specimen was isolated to provide tissue material properties. Structural properties were calculated from the results of cyclic and failure uniaxial tensile tests.

RESULTS

Quadruple-strand constructs had a tensile strength of 205.8 ± 68.2 N and a stiffness of 133.1 ± 46.3 N/mm. Single strands had a tensile strength of 66.9 ± 26.3 N and a stiffness of 43.8 ± 14.7 N/mm. Material properties were similar to a prior study.

CONCLUSIONS

The average maximum tensile strength for the quadrupled plantaris grafts exceeded the strength of the intact anterior talofibular ligament of 139 to 161 N; therefore, the quadruple plantaris construct may be a viable autograft for foot and ankle ligament reconstruction.

CLINICAL RELEVANCE: The tensile strength of the plantaris tendon is comparable to, or stronger than, other grafts already in use and offers a donor site that may result in negligible loss of strength.