Complications
Osteoarthritis
Osteoarthritis (OA), most frequently of the subtalar joint, is the most common overall complication after talar neck and body fractures.[15] OA is also the complication most likely to lead to secondary reconstructive surgery after talar neck fracture,[9,13] accounting for 18 of 26 secondary surgeries in the 2004 series by Sanders et al,[13] Published series with long-term follow-up data report subtalar arthritis developing eventually in most of the cases of the talar neck fracture.[15] Tibiotalar arthritis occurs approximately half as frequently as subtalar arthritis, typically in conjunction with subtalar arthritis rather than in isolation.[1,13] In talar body fractures, isolated tibiotalar arthritis does occur; the rate of tibiotalar arthritis in the 2003 series by Vallier et al[12] after a mean 33-month follow-up was 65%, with 35% exhibiting subtalar arthritis.
Treatment options for tibiotalar arthritis include arthrodesis and total ankle arthroplasty (Table 1). Total ankle arthroplasty has been favored in some studies relative to arthrodesis with improved functional outcomes and better capacity to restore optimal gait mechanics than arthrodesis,[34] although the rates of subsequent surgery may be higher after arthroplasty relative to arthrodesis.[35] The preferred approach for subtalar arthritis is arthrodesis. A recent retrospective review of 121 cases comparing arthroscopic with open techniques demonstrated improved pain and function in both groups, equivalent union and complication rates, and earlier return to work and activities of daily life in the arthroscopic group.[36]
An emerging solution for pantalar OA is total ankle arthroplasty with total talar prosthesis. In 22 patients with a mean 35-month follow-up treated with this technique, functional scores, pain, and range of motion improved markedly.[37] This remains to be compared with combination subtalar fusion and total ankle arthroplasty, which has also demonstrated favorable functional outcomes in small series.[38]
Osteonecrosis
Osteonecrosis or avascular necrosis has long been the most dreaded complication in the treatment of talus fractures, albeit second to subtalar arthritis in frequency. A 2015 systematic review of 26 studies with 980 fractures demonstrated osteonecrosis in 31% overall, with rates of 10%, 27%, and 53% across Hawkins types I through III, respectively.[15] Looking specifically at studies published after 2000, the overall rate was 25%, with 8%, 21%, and 45% across types I though III, suggesting that improved techniques may have slightly decreased the rate of osteonecrosis.[15]
Talar dome subchondral lucency, the Hawkins sign, is a reassuring sign of talar revascularization seen on radiographs in some patients at the 6 to 9 week time point (Figure 5).[39] The presence of a Hawkins sign is considered to reliably exclude the possibility of osteonecrosis, although its absence is nonspecific.[39]
Figure 5.
Radiograph showing the Hawkins sign present in a 46-year-old man 2 months after the treatment of a talar neck fracture.
The most common diagnostic criterion for osteonecrosis is increased radiodensity of the talus relative to adjacent osseous structures.[15] The mean time point for this appearance in one recent series was 6.9 months, with a range from 3 to 9 months.[9] MRI may permit earlier diagnosis but can be confounded by metallic artifact. With no agreed on interventions for early osteonecrosis, MRI has not yet become widely favored.
Little consensus exists regarding the treatment of osteonecrosis.[40] Although a period of prolonged non-weight-bearing (beyond 3 months) was encouraged historically, this was not shown to prevent progression or collapse and has largely fallen out of favor.[40] Other nonsurgical treatments include patellar tendon-bearing bracing treatment that has demonstrated limited efficacy in isolation and extracorporeal shock wave therapy, which has shown promising results in a single trial but remains experimental.[40] A period of initial observation may be warranted. After the initial diagnosis of osteonecrosis, many patients may eventually demonstrate revascularization without collapse, as did 44% of osteonecrosis cases in a 2014 series.[9] In addition, many patients with radiographic osteonecrosis may be asymptomatic. In one review of 114 fractures with a mean 9-year follow-up, osteonecrosis occurred in 39, 16 were symptomatic, and eight were found to have talar dome collapse by the final follow-up.[10]
Persistent symptomatic osteonecrosis may be treated surgically (Table 1). Three general categories of procedures are available: joint-sparing (core decompression and vascularized bone grafting), joint-sacrificing (talar replacement), and salvage (arthrodesis).[40] Joint-sparing procedures aim to preserve native talus anatomy by inducing healing of the devascularized area. Core decompression has been shown to improve functional outcomes in patients with atraumatic osteonecrosis; however, there is little documented experience in posttraumatic cases.[40] A more promising joint-sparing treatment may be vascularized bone grafting from the cuboid. In a recently reported series of 13 patients who underwent this treatment, notable improvement in health-related quality of life was demonstrated with treatment failure in 2 of 13.[41] Postoperative MRI demonstrated partial return of the marrow signal in the necrotic talus, indicating some revascularization.
Two research groups in Japan and Thailand have investigated a joint-sacrificing, but motion-sparing, treatment of talar osteonecrosis, talar body, or total talar prostheses.[42,43] Harnroongroj and Harnroongroj[42] reported 10- to 36-year follow-up data on 33 stainless steel talar body prostheses, 26 of which treated posttraumatic osteonecrosis. At the final follow-up, 5 prostheses had failed and 28 were still in place. All 28 patients with the prosthesis still in place could use a bicycle, walk on a smooth surface, and ascend and descend stairs. Taniguchi et al designed an alumina ceramic total talar prosthesis, custom-made based on a contralateral talus CT. They reported 2- to 8-year follow-up data in a 2015 study.[43] The range of motion was maintained with a mean 5.4° of dorsiflexion and 32° of plantar flexion; all patients reportedly had returned to work and activities of daily living, pain scores improved, and no infections were found.
Despite these promising early results with joint-sparing and joint-sacrificing treatments, the most common surgical treatment of talar osteonecrosis remains salvage treatment with arthrodesis (Figure 6). One option for talar osteonecrosis involving the ankle joint is tibiotalar fusion, either open or arthroscopic-assisted. Current data slightly favor the arthroscopic-assisted technique; a 2018 systematic review reported improved clinical scores and decreased complication rates with the arthroscopic technique, although union rates were similar.[44] Kendal et al[45] reported on 15 patients with talar osteonecrosis treated with the arthroscopic-assisted technique, resulting in successful fusion in all cases and resolution of pain in 13 of 15. Three patients required a second surgery for subtalar arthrodesis.
Figure 6.
The patient is a 56-year-old man presenting with osteonecrosis of the right talar body. A, AP radiograph of the talar neck fracture with subsequent osteonecrosis of the talar body. Lateral radiograph showing osteonecrosis of the talar body. B, AP radiograph 2 years after hindfoot fusion nail and iliac crest bone graph demonstrating a fused tibiotalar joint. Lateral radiograph showing a fused tibiotalar joint.
The most common arthrodesis technique for talar osteonecrosis in recent series has been tibiotalocalcaneal (TTC) fusion with a retrograde intramedullary rod.[40,46–48] This can be combined with the use of structural femoral head allograft,[40] autograft from the fibula,[49] or posterior iliac crest autograft[48] to address large bone defects. Functional results are overall favorable with TTC arthrodesis. Tenenbaum et al[47] reported on 14 posttraumatic cases with mean a 26-month follow-up. All achieved bony union, 42% needed an ambulatory aid, and the mean American Orthopaedic Foot and Ankle Society (AOFAS) scores improved from 33 to 72. Abd-Ella et al[48] reported a 23-month follow-up of 12 posttraumatic cases and reported initial osseous union in 67%, subsequent union after revision surgery in an additional 25%, and improvement in mean AOFAS scores from 39 to 77. In addition to favorable subjective functional outcomes, TTC arthrodesis improves objective gait measures such as gait velocity and ankle moment.[50]
J Am Acad Orthop Surg. 2020;28(20):e878-e887. © 2020 American Academy of Orthopaedic Surgeons
