Examination begins with observation, especially when you have the opportunity to watch the patient walk into the exam room. Having the patient walk as part of the exam is informative, and observing overall lower extremity alignment and gait pattern is critical. Restricted ankle motion leads to early heel rise and a bent knee gait. The posture of the forefoot when it strikes the ground should be noted, as excessive forefoot varus or valgus is important to consider in surgical planning. Upon standing, the position of the hindfoot should be recorded as well. External rotation of the lower extremity is a common feature of patients with ankle arthritis.

The seated exam includes evaluation of range of motion in the ankle, hindfoot, midfoot, and forefoot. Ankle stability should be assessed by drawer testing, with the foot in both plantarflexion and neutral position. This investigates the competence of the anterior talofibular ligament (ATFL) and CFL, respectively. Talar tilt should also be assessed. Foot alignment is important as deformity in the foot may cause secondary ankle disease. For example, pes planus with medial column instability may be associated with secondary ankle valgus and eventual degenerative change. Conversely, realignment of a deformed ankle can alter the foot position and adversely or positively affect function of other joints, particularly the subtalar joint. If compensatory foot deformities are noted on exam, their passive correctability has to be assessed. Tendons should be palpated to identify potential confounding sources of pain. Furthermore, finding the point of maximal tenderness during the exam may help in diagnosis if there are multiple degenerative joints. A vascular exam should be performed with palpation of pulses and assessment of the distal capillary refill. The exam is completed with a neurologic assessment looking for motor or sensory deficits.

Weight-bearing radiographs will better elicit deformity or soft tissue instability and should be obtained if possible. The four radiographic views we use in our clinic to evaluate ankle pain include the anteroposterior, lateral, mortise, and hindfoot alignment view. Radiographs of the degenerative ankle will show joint space narrowing, osteophyte formation, subchondral sclerosis, and subchondral cysts. When considering arthroscopic tibiotalar arthrodesis,
increased scrutiny should be applied to evaluating these standard radiographs. Anterior subluxation of the talus should be noted. Significant anterior subluxation will be difficult to correct with the limited capsular releases afforded during an arthroscopic approach. Special attention should be directed toward assessing degeneration of the distal tibiofibular joint and the formation of osteophytes in the medial and lateral gutters of the ankle. Failure to identify bony impingement in these areas can result in the inability to correct deformity or result in persistent pain postoperatively. If there is concern that these areas cannot be dealt with adequately through an arthroscopic approach, then open tibiotalar arthrodesis should be pursued.

The hindfoot alignment view is important in the evaluation hindfoot varus/valgus and ankle coronal plane deformity (Fig. 93.2) (15). It is taken with the patient standing on a platform facing a collector that angles away from the platform at 20°. The X-ray tube is posterior to the ankle with the beam perpendicular to the plane of the film at the level of the ankle. On average, the most inferior aspect of the calcaneus is centered along the longitudinal mid-axis of the tibia.

CT is an excellent adjunct to standard radiographs to better delineate the three-dimensional bony anatomy. Arthroscopic tibiotalar arthrodesis may be difficult in the setting of significant bone loss or collapse, and CT allows for better evaluation of the bony structures. In addition, due to the high prevalence of posttraumatic tibiotalar arthritis, there is often orthopedic hardware from previous interventions present, and unlike MRI, cCTallows for visualization near hardware. Noninvasive joint distraction plus air-contrast arthrography enhances visualization of the ankle articular features, and can be used if there is a need to delineate between focal and global ankle arthritis (16). MRI has limited use unless one suspects an osteochondral lesion of the talus, osseous necrosis or ligamentous abnormality that will alter patient care. In such cases, MRI arthrography may be advantageous.

Selective fluoroscopically guided injections can also be helpful in patients who have clinical or radiographic findings that suggest more than one source of pain. It is reasonable to expect 75% pain relief in an area that is injected (17). It is important to identify the patients’ ankle pain as global (affecting a majority of the joint) or focal (specific region), as this distinction may guide the treatment options. It is particularly important to identify patients with coexisting subtalar pain as that population needs to be counseled more intensely about the risks of residual pain and progression of adjacent joint arthritis.

An arthroscopic ankle arthrodesis can be completed through either anterior or posterior arthroscopic portals. The anterior approach is favored for most cases, unless a subtalar fusion is also considered or there are soft tissue reasons (e.g., free flap, severe burns) not to do an anterior approach. In this situation, prone positioning and posterior portals would allow for arthroscopic preparation of both the tibiotalar and subtalar joints. For an anterior arthroscopic approach, the patient is placed in a supine position on the operating table with the operative leg in either a well leg holder (Fig. 93.3) or flat on the operative table depending on the type of external distractor used. When the leg is left out of the well leg holder, the bed can be adjusted (combination of reflex, Trendelenberg, and leg lowering) to create countertraction. Invasive distraction with a calcaneal or talar “skinny” wire or noninvasive distraction with an ankle strap can be used to facilitate joint visualization. If external strapping techniques are used to distract the joint, the force (generally <25 lb [11.3 kg]) should be decreased during preparation of the anterior talar dome, as this takes tension off the anterior capsule, allowing for easier access to talar dome. Use of thigh tourniquet is optional; we always place a tourniquet in case needed, and rarely inflate it. Prepping above the knee allows for assessment of rotational alignment. Prior to portal creation, we mark out landmarks including malleoli, palpable branches of the superficial peroneal nerve, and the expected level of the tibiotalar joint space.

For anterior arthroscopy, standard anteromedial and anterolateral portals are created. The joint is insufflated by injecting approximately 20 cc (20 mL) of normal saline using an 18G needle placed anteromedially into the joint. The anterolateral portal is created after needle localization under direct arthroscopic visualization (Fig. 93.4). Both portals are created using the “nick and spread” technique to minimize the risk of injury to branches of the superficial peroneal nerve. For arthroscopic arthrodesis, the portals should be made larger than would normally be done for standard arthroscopy. The larger portals aid in the introduction of larger instruments that will facilitate a timely arthroscopic debridement. To enhance visualization and fluid flow, a 4.0-mm scope is routinely used for arthroscopic visualization. An arthroscopic pump is typically used to distend the joint; the pump is set at the lowest pressure needed to achieve visualization, and is generally adjusted several times in the operation to reduce tissue edema. It is not uncommon to have a significant amount of anterior capsular scarring and synovitis, which can make access to the joint difficult. This synovitis and scarring should be removed to facilitate visualization (Fig. 93.4).