Peroneal tendon disorders are fairly common after ankle inversion injuries or in patients who have chronic wear and tear associated with the pes cavus foot type. Peroneus brevis tendon partial tears and tendinosis seem to be more prevalent than peroneus longus tendon disorders. I want to dedicate this blog to a simple yet effective surgery for severe tendinosis and/or complete rupture of the peroneus longus tendon.
The peroneus longus muscle originates at the lateral condyle of the tibia and fibular head. The peroneus longus tendon courses behind the peroneus brevis tendon at the ankle and inferior to the peroneal tubercle. The tendon then makes a sharp turn at the level of the cubital tunnel to course under the tarsal bones to attach to the plantar aspect of the first metatarsal and medial cuneiform. The peroneus longus everts and plantarflexes the foot. In addition, the muscle will plantarflex the first ray.
As I alluded to in prior blogs, patients with metatarsus adductus and a cavus foot type are predisposed to having lateral ankle and foot pain syndromes. When I have a patient who has a peroneus longus tendon rupture, he or she usually has a pes cavus foot type.
I feel that peroneus brevis tendon disorders are more common in foot types other than pes cavus. Inversion ankle sprains are common in the general population and affect individuals with all foot types. The peroneus brevis tendon is more likely to become damaged than the peroneus longus tendon due to anatomic considerations. I believe the peroneus longus tendon is better insulated distally in the cubital tunnel and therefore, there is more strain effect against the peroneus brevis tendon during an inversion event.
When I have a patient with symptomatic pain and dysfunction with the peroneus longus tendon, I am more likely than not going to excise the tendon. Biomechanically, it actually helps in the pes cavus foot type as you reduce pull of the first metatarsal in plantarflexion. The peroneus brevis tendon is a major antagonist to the tibialis posterior tendon and if one removes that tendon, an adductovarus condition will develop. Therefore, unlike the peroneus longus tendon, the peroneus brevis tendon needs anatomic repair.
The surgical excision of the peroneus longus tendon may seem radical but it is funny how we think sometimes. For example, when I talk to colleagues about a flatfoot surgery, fusion of the first metatarsocuneiform joint often comes up as it is a good way to stabilize the medial column. However, a common response is, “I hate to fuse a normal joint.” These are the same people who do not think twice about doing a Lapidus bunionectomy. That is destruction of the joint as well but it seems to be more accepted.
In cavus foot surgery, a peroneal stop procedure has been popular to address the excessive plantarflexion of the first ray, assuming that it is a flexible deformity. As you know, the procedure involves anastomosing the longus tendon with slack to the brevis tendon under tension. In essence, that is what I am doing when I excise the peroneus longus tendon. I cut out the diseased portion of the tendon, which is typically between the lateral malleolus and the cubital tunnel. The brevis and longus tendons are anastomosed in the retromalleolar region. That way, the patient still has ankle flexor forces and the procedure may help reduce forefoot valgus.
In summary, consider excision of diseased peroneus longus tendon versus reconstruction in patients that have a pes cavus foot type and/or excessive flexible plantarflexion of the first ray (forefoot valgus).