Ankle Arthroscopy Technique

The need to perform ankle arthroscopy varies according to the specific condition present. Usually, ankle arthroscopy is indicated after the failure of conservative measures, such as physical therapy, nonsteroidal anti-inflammatory drugs (NSAIDs), ankle braces, heel lifts, or wedges. It is also indicated in cases where symptoms persist and study results are inconclusive.

Although ankle arthroscopy is useful in addressing intra-articular pathology, the underlying cause of this pathology could be extra-articular, and this possibility should also be addressed. Thus, ankle arthroscopy is sometimes performed concomitantly with other procedures to address the underlying pathology. For example, ankle arthroscopy may address soft-tissue impingement or an osteochondral lesion, ^{[31, 30]} but if there is underlying lateral ligament laxity or a hindfoot varus deformity, additional procedures are appropriate.

In a retrospective study of patients treated for acute ankle fracture in the United States from 2007 to 2011, Ackermann et al found that despite the availability of good evidence in favor of performing arthroscopy at the time of ankle fracture treatment, only a small percentage of US surgeons performed these procedures concurrently during this time period. ^[32]

A sterile tourniquet can be used and is usually applied on the leg just above the ankle. However, the ankle joint distention (see below) with the irrigation fluid may be enough to provide a bloodless field and is sufficient in some cases.

A high inflow and outflow system is helpful in obtaining hemostasis; it permits improved visualization and irrigation of debrided material; and it can be adjusted throughout the operative procedure.

In establishing the arthroscopy portals, it is important to be aware of the surface anatomy. A skin marker is used to outline the important neurovascular structures in the vicinity of the portals and the joint line. An 18-gauge needle is introduced medial to the tibialis anterior tendon, and 15-20 mL of saline or 0.25% bupivacaine solution with epinephrine is injected to distend the ankle joint (see the image below).

At the portal site, a No. 11 blade is used to incise the skin layer only, and a fine mosquito hemostat forceps is then used to perform blunt dissection into deeper layers and to enter the capsule.

The two most commonly used anterior portals are the anteromedial and anterolateral portals (see the image below). An anteromedial portal is placed just medial to the anterior tibial tendon at the joint line. An anterolateral portal is placed just lateral to the peroneus tertius tendon; this is at the level of, or slightly proximal to, the joint line.

Posterior portals are also useful during arthroscopy of the ankle. These portals are placed immediately medial or lateral to the Achilles tendon or through its substance just distal to or at the joint line. A posterolateral portal is established in the soft spot just lateral to the Achilles tendon, 1.2 cm (0.5 in.) above the tip of the fibula. Because of the potential for serious complications and the difficulty of maneuvering the arthroscope, trans-Achilles and posteromedial portals are contraindicated in most instances.

Hirtler et al, in a cadaver study using 20 matched pairs (n = 40) of anatomic ankle specimens, evaluated accessibility of the talar dome in neutral position, dorsiflexion, or noninvasive distraction in posterior ankle arthroscopy. ^[33]  In neutral position, 13.7 ± 1.2 mm of the talar dome was reached laterally and 14.0 ± 1.0 mm medially; in maximal dorsiflexion, 19.0 ± 1.1 mm was reached laterally and 19.8 ± 1.4 mm medially; and in noninvasive distraction, 16.1 ± 1.5 mm was reached laterally and 15.7 ± 1.0 mm medially. There was significantly better reach in dorsiflexion laterally and medially. Accessibility of the talar dome in maximal dorsiflexion was superior to that in neutral or in noninvasive distraction.

Transmalleolar portals through either the tibia or the fibula are used in cases where a more direct approach is required—for example, when Kirschner wires are drilled into the talar dome under fluoroscopic and endoscopic control for the purpose of establishing new vascularity in an osteochondral lesion. Transtalar portals can also be used for retrograde drilling and possibly for bone-grafting osteochondral lesions of the talus.

A 30° 2.7-mm arthroscope is used initially, and the ankle is visualized through all portals to perform a systematic examination of the entire ankle joint. Interchangeable cannulas should be used to minimize the trauma associated with the passage of instruments.

Debridement includes removal of the inflamed synovium, thickened adhesive bands, inflamed capsular bands and ligamentous tissue, osteophytes, and loose bodies (see the images below). Debridement is performed to expose the underlying cartilage.

Bony spurs causing impingement are shaved with arthroscopic burrs and shavers. Employ extreme caution when using these instruments; never direct them dorsally into the soft tissues, because doing so may injure the neurovascular structures.

Osteochondral lesions of the talus that are located anterolaterally can be approached through the anterior portals for curettage and for microfracture or drilling. Lesions that are located posteromedially can be visualized with plantarflexion of the ankle. If a direct approach is required for antegrade or retrograde drilling, a microvector drill guide is used to establish a transosseous portal.

Preparation of surfaces for arthroscopic ankle arthrodesis requires thorough denudation of all hyaline cartilage exposure of vascular subchondral bone. In addition, multiple puncture holes in the prepared surfaces allow easy vascular ingress across the surfaces to be fused.

After the arthroscopic procedure has been completed, the joint is thoroughly irrigated, with the remaining fluid expressed out of the joint. The portals are closed with absorbable sutures and covered with sterile gauze and soft, bulky dressing. A posterior splint is applied to provide comfort and allow the portals to heal. Patients are instructed to keep the limb elevated and to exercise the toes, knees, and hips. Cryotherapy can help minimize and reduce the postoperative swelling.

In a review of 53 consecutive ankle arthroscopies, Barber et al reported nine complications (complication rate, 17%), which included permanent dorsal sensory nerve injury (three cases), synovial fistula (two), wound infection (three), and  reflex sympathetic dystrophy (one). ^[34] Other complications identified in a literature review were instrument breakage, synovitis, painful scars and nodules, and fibula fracture.

In a study involving 612 patients undergoing ankle arthroscopy, the overall complication rate was 9.8%. Among these patients, the most common complications were neurologic (49%), primarily involving the superficial peroneal nerve (56%), the saphenous nerve (24%), or the sural nerve (20%). Other complications included superficial infection, deep infection, adhesions, fractures, instrument failure, ligament injury, and incisional pain. ^[14]

Zengerink et al reported on complications in ankle arthroscopy after a review of a consecutive series of patients undergoing ankle arthroscopy in their hospital between 1987 and 2006. ^[35] Anterior ankle arthroscopy was performed by means of a two-portal hindfoot approach with a dorsiflexion method and intermittent soft-tissue distraction. Complications were registered in a prospective national registration system. Apart from this complication registry, patient records, outpatient charts, and operative reports were reviewed. Patients with a complication were asked to visit the hospital for clinical examination and assessment of permanent damage and persisting complaints.

The overall complication rate was 3.5% in 1305 procedures. ^[35] Neurologic complications (1.9%) were related to portal placement. Age was a significant risk factor for complications. Most were transient and resolved within 6 months. Complications did not lead to functional limitations. Residual complaints did not influence daily activities. The authors concluded that the complication rate was less than half of that reported in the literature (3.5% vs 10.3%), that the dorsiflexion method for anterior ankle arthroscopy can prevent a significant number of complications, and that posterior ankle arthroscopy via a two-portal hindfoot approach is safe with a complication rate comparing favorably to anterior ankle arthroscopy.

Zekry et al reviewed the literature on complications following anterior and posterior ankle arthroscopy and identified a total of 107 papers, of which 55 were deemed appropriate for analysis. ^[36] The overall complication rate of ankle arthroscopy was found to be in the range of 3.4-9%. No life-threatening complications were identified with either anterior or posterior ankle arthroscopy. The most common complications after anterior and posterior ankle arthroscopy were superficial peroneal nerve injury and temporary Achilles tendon tightness, respectively.