Peroneal Nerve Dysfunction due to Multiligament Knee Injury: Patient Characteristics and Comparative Outcomes After Posterior Tibial Tendon Transfer.

OBJECTIVE: To objectively compare outcomes of nonoperative management and posterior tibial tendon (PTT) transfer for peroneal nerve injury due to multiligament knee injury (MLI).

DESIGN: Retrospective cohort study with prospective follow-up.

SETTING: Tertiary care institution.

PATIENTS: Ten patients with peroneal nerve injury due to MLI (5 managed nonoperatively, 5 with PTT transfer) were evaluated and a control group of 4 patients without peroneal nerve injury.

INTERVENTIONS: Clinical examination, subjective questionnaires, and 3-D motion capture gait analysis during flat-ground walking and stair descent.

MAIN OUTCOME MEASURES: The primary outcome measure was the result of gait analysis. The results of subjective questionnaires were a secondary outcome measure.

RESULTS: Dorsiflexion was significantly reduced at initial contact and mid-late swing phase in the nonoperative cohort. The PTT transfer cohort demonstrated increased dorsiflexion at each of these time intervals compared with patients managed nonoperatively, restoring symmetry between limbs. The PTT transfer cohort demonstrated similar gait patterns to controls but tended to be more everted. Ground reaction force was increased in the uninvolved limb in the PTT transfer group during gait and step down. There were no statistically significant differences in AOFAS, FAAM, IKDC, or Lysholm results.

CONCLUSIONS: Posterior tibial tendon transfer is an option to restore dorsiflexion and eliminate the need for an orthosis in patients with foot drop due to MLI. Gait analysis demonstrates a significant improvement in sagittal plane ankle kinematics after PTT transfer. The trade-off is subtle instability, highlighting the dynamic stability that the PTT provides.