Arthroscopic Repair of Ankle Instability With All-Soft Knotless Anchors

Abstract

In recent years, arthroscopic and arthroscopically assisted techniques have been increasingly used to reconstruct the lateral ligaments of the ankle. Besides permitting the treatment of several comorbidities, arthroscopic techniques are envisioned to lower the amount of surgical aggression and to improve the assessment of anatomic structures. We describe our surgical technique for arthroscopic, two-portal ankle ligament repair using an all-soft knotless anchor, which is made exclusively of suture material. This technique avoids the need for classic knot-tying methods. Thus it diminishes the chance of knot migration caused by pendulum movements. Moreover, it avoids some complications that have been related to the use of metallic anchors and some currently available biomaterials. It also prevents prominent knots, which have been described as a possible cause of secondary complaints.

Fig 1

Skin tears caused by knot tying (arrows) after arthroscopic surgery.

Fig 2

Patient positioning showing left ankle surgery, with a sandbag under the ipsilateral buttock for internal rotation of the limb (A). Correct placement of the medial portal is a key to success. (B, C) The contour of the medial malleolus is drawn on the skin up to the joint line (yellow arrows). (B) In plantar flexion, the tibialis anterior tendon has a more medial position (entrapped between surgeon's fingers), whereas (C) in dorsiflexion, it slides to the center of the joint (between the red arrows).

Fig 3

Creation of medial portal in a left ankle. (A) In dorsiflexion, at the level of the joint line (red line), a soft spot can be felt just medial to the tibialis anterior tendon (blue lines). Notice that in plantar flexion position the tendon is considerably more medial (dashed lines). The medial portal is created medial to the intersection of the tibialis anterior tendon and the joint line. (B) A surgical blade is used to cut the skin. (C, D) A mosquito clamp is used to bluntly dissect the soft tissue until reaching inside the joint. The ankle is kept in dorsiflexion at all times to open the anterior “working area,” diminish tension of the surrounding structures, and protect the joint cartilage.

Fig 4

(A) As shown in a left ankle, a 22-gauge needle is used to assist in portal placement 1.0 to 1.5 cm anterior to the tip of the fibula while transillumination is used to protect the superficial peroneal nerve. (B) The tip of the lateral malleolus (blue arrow) and the remnant of the anterior talofibular ligament (yellow arrow) are identified. The talus is also visible (asterisk). (C, D) The surgical blade is used to cut the skin, and blunt dissection by a mosquito clamp is used to penetrate the joint, lowering the risk of iatrogenic injuries.

Fig 5

(A, B) Arthroscopic view of the lateral gutter of a left ankle through the anteromedial portal. The quality of the anterior talofibular ligament remnant (yellow arrows) must be inspected, and the contour of the tip of the medial malleolus (blue arrows) is identified. (C) A key to success is for the surgeon to prepare the tip of the lateral malleolus using a shaver blade until reaching bleeding bone before inserting the anchor (black arrow). (D) JuggerKnotless anchor (Zimmer Biomet) placement through the lateral portal. (E) Inside view of the anchor guide (the arthroscope is in the medial portal). (F) Introduction of the anchor. (G) Verification that both ends of the anchor are adequately sliding. (H) Confirmation of the pullout resistance of the anchor by raising the leg from the table while pulling through the anchor wires.

Fig 6

(A) An 18-gauge needle with a No. 3-0 nylon loop is introduced through the accessory lateral portal and serves as a suture passer. (B) Two anchors have been inserted in the lateral malleolus (red arrows). The needle (yellow arrow) trespasses the proximal half of the anterior talofibular ligament remnants. (C) A grasper is used to retrieve the nylon loop. (D) By use of the grasper, the nylon loop is retrieved outside the joint and the solid-blue wire from the first anchor is passed through. The nylon loop (including the solid-blue wire) is then pulled out through the skin. (E, F) Retrieval of the solid-blue wire through the accessory lateral portal with a hook probe. (G) The solid-blue wire of the anchor is passed through the nitinol loop of the deployment device of the anchor. (H) A second, blue-white loop is detached and slides over the solid-blue wire. Soft tissue is tensioned against the footprint by pulling the solid-blue wire. A small pull on the blue-white wire locks the mechanism.

Fig 7

Left ankle with the arthroscope through the medial portal. (A) The anterior talofibular ligament remnant (yellow arrows) is reattached to the footprint (black arrow) by the first anchor. (B) Final tensioning of the anterior talofibular ligament remnant is achieved in one single continuous movement. (C) The free space in the lateral gutter has diminished. There are no bulky knots around the anchor attachment (black arrow), and the two ends of the second anchor are visible (orange arrows). These are used to perform a pants-over-vest reinforcement with the inferior extensor retinaculum. (D) The second anchor (orange arrow) is also pulled in a continuous movement to tension the tissue of the inferior extensor retinaculum toward the lateral malleolus (red chevrons).

Fig 8

(A, B) Computed tomography evaluation of a left ankle showing the small defects (yellow arrows) caused by the 2.1-mm anchors 2 months postoperatively. (C, D) Magnetic resonance imaging T1 evaluation of left ankle 2 months postoperatively. Some signal changes are explained by the short interval from surgery. (D) On the sagittal view, both tunnels can be identified (blue and yellow arrows).