Anterocentral Portal in Ankle Arthroscopy

Abstract

Background: The anterocentral portal is not a standard portal in anterior ankle arthroscopy due to its proximity to the anterior neurovascular bundle. However, it provides certain advantages, including a wide field of vision, and portal changes become redundant. The purpose of this study was to evaluate the neurovascular complications after anterior ankle arthroscopy using the anterocentral portal.

Methods: We retrospectively identified patients who had undergone anterior ankle arthroscopy with an anterocentral portal at our institution from 2013 to 2018. Medical record data were reviewed and patients were invited for clinical follow-up, where a clinical examination, quantitative sensory testing for the deep peroneal nerve, and ultrasonography of the structures at risk were performed. A total of 101 patients (105 arthroscopies) were identified and evaluated at a mean follow-up of 31.5 ± 17.7 months.

Results: Leading indications to surgery were heterogeneous and included anterior impingement (48.6%), osteochondral lesions of the talus (24.8%), chronic ankle instability (14.3%), and fractures (8.6%). The overall complication rate was 7.6%, and no major complications were observed. In 1.9% (2/105) of the cases, the complications were associated with the anterocentral portal and included injury to the medial branch of the superficial nerve (1/105) and to the deep peroneal nerve (1/105). Injury to the deep peroneal nerve was associated with a loss of detection and nociception. There were no injuries to the anterior tibial artery. In 41.9% (44/105) of the cases, only 1 working portal was used in addition to the anterocentral portal, and in 19% (20/105) the anterolateral portal could be avoided. Ultrasonography confirmed the integrity of the deep peroneal nerve, the medial branch of the superficial peroneal nerve, and the anterior tibial artery in all patients. Patients with nerve injuries associated with the anterocentral portal showed no signs of neuroma or pseudoaneurysm.

Conclusion: Using a standardized technique, the anterocentral portal in ankle arthroscopy is safe with a low number of neurovascular injuries and can be recommended as a standard portal. The anterolateral portal remains associated with a high number of injuries to the superficial peroneal nerve.

Level of evidence: Level III, retrospective cohort study.

Keywords: ankle arthroscopy; anterocentral portal; deep peroneal nerve; nerve injury; neurovascular complication; superficial peroneal nerve.

Figure 1.

(Left) Patient positioning and (right) marked-out anatomical landmarks and arthroscopic portals. The anterocentral portal is located between the extensor hallucis longus and extensor digitorum longus tendon.

Figure 2.

Schematic of the affected skin area of 2 patients with nerve injury associated with the anterocentral portal. The affected area was marked out using the pinprick test. (A) Injury to the deep peroneal nerve (DPN) with hyposensitivity in the first web space. (B) Injury to the medial branch of the superficial peroneal nerve (SPN).

Figure 3.

Box plots for 5 QST parameters (VDT, CDT, WDT, CPT, HPT) of all patients. Values above zero demonstrate a gain of function on the side that has been operated on, whereas values below zero show a loss of function. Outliers were defined as a deviation of Q1 and Q3 of more than 1.5 interquartile ranges. Injury to the DPN resulted in loss of function on VDT, CDT, CPT, and HPT. CDT, cold detection threshold; CPT, pain threshold; HPT, heat pain threshold; QST, quantitative sensory testing; VDT, vibration detection threshold; WDT, warm detection threshold.

Figure 4.

Transverse ultrasound scan of the anterior ankle at the joint level without pathological findings. The anterior neurovascular bundle is located between the extensor hallucis longus (EHL) and extensor digitorum longus (EDL) tendons. The deep peroneal nerve (void arrow) runs together with the anterior tibial artery (ATA) and adjacent veins (VTA). Scale indicates depth in centimeters.

Figure 5.

Ultrasound scan of the anterolateral ankle showing a neuroma of the lateral branch of the superficial peroneal nerve adjacent to the anterolateral portal. Scale indicates depth in centimeters.