Anna Sprinchorn: Peroneus longus to brevis tendon transfer – a feasible procedure?

Abstract

The peroneus (also termed fibularis) longus and brevis muscles stabilize the lateral side of the ankle during gait. Both tendons can be injured through ankle supination trauma. In cases of more extensive damage to the tendons, a direct repair is not possible, and surgery with a peroneus longus to brevis tendon transfer has been suggested with an added lateral ankle ligament reconstruction, and sometimes a calcaneal osteotomy, in the case of hindfoot varus. This thesis explores the outcome after this surgery:

• Sixteen patients (17 feet) had a follow-up 2-6.5 years after surgery, that also included an osteotomy to the first metatarsal. The results showed good patient-reported and clinical outcome, but slight residual hindfoot varus.
• The difference in anatomic structure between the two muscles was studied and sixteen cadaver legs dissected. Both muscles are pennate, but the peroneus longus had longer fibre length and is 1.4-4.6 times larger in volume than peroneus brevis. The good holding power of peroneus brevis is not attributable to muscle anatomy.
• Thirty-two patients filled out the Foot and Ankle Outcome Score (FAOS) and SF-36 and conducted a gait analysis before, and at six and 12 months after surgery. The FAOS improved significantly, and the three physical domains in SF-36 improved. In the gait, the peak pressure under the first metatarsophalangeal joint diminished. Compared to a healthy control group, there was no other significant difference in the gait kinematics. The FAOS had a moderate correlation to the velocity.

Drawing on the evidence presented in this thesis we demonstrate that the peroneus longus to brevis tendon transfer, with a lateral ankle ligament reconstruction and additional calcaneal osteotomy, is a surgical procedure that achieves good outcomes in terms of patient-reported outcome and gait in patients with irreparable tears of the peroneus tendons.