The first account of an injury to the talus was from Fabricius of Hilden in 1608, who treated a man whose talus had ruptured its surrounding ligaments and burst out through the skin…..That probably didn’t end well.
As a starting point, I can recommend reading “Aviator’s Astragalus” by WD Coltart, (JBJS, Vol 34-B, No 4, 1952, 545-566), erstwhile Orthopaedic Specialist to the Royal Air Force. It is full of historic pearls such as the one above.
He quotes Anderson’s report of 1919, when he coined the name ‘Aviator’s Astragalus’ for the injury sustained by the foot when World War 1 aviators crashed with their feet on the rudder bar. The mechanism was felt in most cases to be forced dorsiflexion of the talar neck against the anterior lip of the tibia.
Coltart analysed 228 injuries to the talus from the RAF between 1940-1945. Nearly 70% of the severe ones resulted from aviation accidents ( n=106). He described fractures with differing degrees of severity: chip/avulsion/compression fractures of head of talus, fractures & fracture-dislocations of the neck of the talus, fractures & fracture-dislocations of the body of the talus, fractures of the neck with posterior dislocation of the body, total dislocation of the talus, and subtalar dislocation.
This was a pretty creditable effort for those days, and a useful contribution. However, as you will see when you get into this topic, a repeating feature in the literature of talar injury seems to be that no single author/group of authors describes the full spectrum of talar injuries in one paper.
In short, the talus can be fractured in any part, in any combination, with varying degrees of displacement & comminution, and with subluxation or dislocation from any or all the joints it articulates with. Since it is a relatively rare injury, it is not surprising that it has taken a lot of time and the evolution pf better record/Xray systems to reveal the full complexity of these injuries.
Coltart advised urgent reduction, & identified the complications as infection, avascular necrosis (AVN), and degenerative (post-traumatic) arthritis; advising against talectomy and for tibiocalcaneal fusion. These features are still the main problems we face today, although we would probably add non-union.
Leland Hawkins in 1970 made a large contribution to the way we think about these injuries, though he concentrated on vertical fractures of the neck rather than talar body fractures which we now understand to be more numerous in modern series. 1970, Hawkins, ‘Fractures of the Neck of the Talus’. JBJS VOL. 52-A, NO. 5. JULY 1970, 991-1002. n=57 fractures in 55 patients. His classification is the best understood, although it doesn’t cover all talar fractures.
His Group 1 was a vertical fracture of the neck, undisplaced. n=6, no AVN.
His Group 2 was displaced vertical neck fracture, the subtalar joint subluxed or dislocated; the ankle normal. n=24, union in all, but AVN in 42%.
His Group 3 was a vertical fracture talar neck, displaced, the body dislocated from both subtalar and ankle joints. n=27, AVN followed in all but 2 (91%). Non-union occurred in 3, all of whom had talectomy.
His overall incidence of AVN was an impressive 58%. In most recent series the incidence overall tends lower, perhaps ~33%.
Famously, Hawkins described the sign of revascularisation subchondral atrophy visible on the AP radiograph of the ankle; a sign which was said to rule out avascular necrosis.
If patients escaped AVN, patients in Group 1 were excellent or good; in Group 2 two-thirds were excellent or good, one third fair/poor. In Group 3, only 2 patients escaped AVN; one was fair, the other poor.
The large majority of patients with AVN had pain and a fair/poor clinical result.
Hawkins’ sign has been found to have a sensitivity of 100% and a specificity of 57.7%. If a full or partial positive Hawkins sign is detected, it is unlikely that AVN will develop at a later stage after injury. (Tezval, Dumont, Sturmer. ‘Prognostic reliability of the Hawkins sign in fractures of the talus‘. J Orthop Trauma. 2007 Sep;21(8):538-43. doi: 10.1097/BOT.0b013e318148c665.)
1977, J. E. Lorentzen, S. Bach Christensen, O. Krogsøe & O. Sneppen
Fractures of the neck of the talus, Acta Orthopaedica Scandinavica, 48:1, 115-120, DOI: 10.3109/17453677708985121
n=123. Follow-up average 22 months. 54 undisplaced, 53 associated with suhtalar dislocation, 16 associated with dislocation of the talus in both ankle joint and subtalar joint.
Of total 123 patients, 21 per cent (26/123) developed avascular necrosis, a lot lower than Hawkins’ series.
31 per cent (38/123) developed talo-crural and 47 per cent (58/123) subtalar osteoarthrosis.
Fifteen per cent (18/123) of the fractures united with considerable deformity, and four per cent (5/123) exibited non-union of the neck. Out of 63 patients with isolated fracture of the neck of the talus, 65 per cent (41/63) reported moderate or severe complaints, and 52 per cent (33163) complained of functional disability often resulting in a change to lighter work. Even among the 54 undisplaced cases there were unexpected numbers of late sequelae, such as osteoarthrosis, subjective complaints and disablement.
Lars Peterson, Ian F. Goldie & Lars Irstam (1977) Fracture of the
Neck of the Talus: AClinicalStudy, Acta Orthopaedica Scandinavica, 48:6, 696-706, DOI: 10.3109/17453677708994820
n=46; follow up 6 years.
‘At follow-up most of the patients complained of symptoms hampering daily activities. Objectively, excellent to good results were obtained in 75% of the non-displaced fractures and in 42% of the displaccd. Delayed union occurred in 15%. Avascular necrosis was found in 15% and degenerative changes
in 97%.’
Canale & Kelly, ‘Fractures of the Neck of the Talus’. JBJS, VOL. 60.A, NO. 2, MARCH 1978, 143-156.
n=71; follow up average 12.7 years.
AVN of the talar body occurred in 52% of the fractures; 2/13 undisplaced fractures, in half of the fractures with subluxation or dislocation of the subtalar joint, and 16/19 of fractures with complete dislocation of the body of the talus.
‘Many patients with avascular necrosis treated conservatively had satisfactory results. The complications of avascular necrosis, malunion, subtalar arthritis, and infection required twenty-five secondary procedures. Triple arthrodesis, tibiocalcaneal fusion, and dorsal beak resection of the talar neck all resulted in a high percentage of satisfactory results, but talectomy did not.’
Canale & Kelly claimed to have described Type 4, a fracture-dislocation with subluxation of the head of the talus from the talonavicular joint. However Pantazopoulos et al in 1974 had already illustrated the Type 4, and called it Type 4, in 1974. (Th. Pantazopoulos, P. Galanos, E. Vayanos, A. Mitsou & G. Hartofilakidis-Garofalidis (1974) Fractures of the Neck of the Talus, Acta Orthopaedica Scandinavica, 45:1-4, 296-306, DOI: 10.3109/17453677408989150).
de Sousa et al, 2009 , ‘LONG-TERM RESULTS OF BODY AND NECK TALUS FRACTURES’.Rev Bras Ortop. 2009;44(5):432-6.
A small study, retrospective, of 11 patients, but using a widely recognised outcome scale (AOFAS). AOFAS score 19-100, average 72.
Prevalence of associated fractures 60%. AVN & post-traumatic arthritis (PTA) present in half.
The authors concluded: ‘There is a great potential for long term functional impairment due to posttraumatic arthritis and chronic pain in this kind of
fracture. Anatomic surgical reduction is the best chance to avoid them but it is not infallible. The avascular necrosis rate correlates with initial fracture displacement, but its occurrence in each specific case is unpredictable’.
A useful overview of CT-identified talar fracture patterns was published in 2013: Dale, Ha, & Chew, ‘Update on Talar Fracture Patterns: A Large Level I Trauma Center Study’ AJR 2013; 201:1087–1092.
n=132 in 122 patients.
The most common fracture location was the body of talus (61%). The most common body fractures were dome compression (26%), lateral process (24%), and posterior tubercle (21%).
Of the 132 fractures, 62% were comminuted. 21 patients (16%) were vertical neck fractures compatible with the Hawkins-Canale classification.
Both radiography and CT were used in 91%, with CT providing additional information in 112 (93%) cases. By use of CT as the reference standard, the sensitivity of radiography for detecting talar fractures was 74%.
The most common fracture missed by radiography was talar dome compression (31% not seen on radiography).
Talar fractures were associated with adjacent joint subluxation or dislocation in more than 66% of the cases and adjacent fracture in more than 72% of the cases.
The clear conclusion is that CT is more or less mandatory in today’s world.
2016, Stake et al, ‘Surgically treated talar fractures. A retrospective study of 50 patients’. Foot and Ankle Surgery 22 (2016) 85–90. http://dx.doi.org/10.1016/j.fas.2015.05.005
n=52 fractures in 50 patients.
VAS score was 69 +/- 18 (mean +/- SD); AOFAS ankle–hindfoot score was 73 +/-17 (mean +/- SD).
OA was seen in 98% and AVN in 65%. Secondary surgery had been performed in 38% of the feet.
Conclusion: ‘Long-term complications were commonly seen after talar fractures and had a significant impact on daily life activities and quality of life. The need for secondary surgery was high. Prolonged follow-up is necessary to detect long-term complications, and the patients should be offered a low threshold for recontact’.
2018, Braun et al, ‘Long-term pathological gait pattern changes after talus fractures — dynamic measurements with a new insole’. International Orthopaedics
https://doi.org/10.1007/s00264-017-3720-y
n=27, followed up after ORIF talus. Follow up mean 78.3 months (range 21-150 months). Assessment = Continuous dynamic pedobarography with a gait analysis insole was performed on a standardized parcours consisting of different gait tasks and matched to the outcome.
Mean AOFAS and Olerud-Molander scores 66 (range 20–100) and 54
(range 15–100). Significant correlations between fracture classification and osteoarthritis (Hawkins: rs = 0.67 / Marti-Weber: rs =
0.5) as well as several gait differences between injured and healthy foot with correlations to outcome were seen: decreased step
load-integral/maximum-load; associations between centre-of-pressure displacement and outcome as well as between temporospatial measures and outcome. Overall, pressure-distribution was lateralized in patients with subtalar joint injury (Δ: 0.5765 N/cm2, p = 0.0475).
Conclusions: Talus fractures lead to chronic gait changes and restricted function. Dynamic pedobarography can identify patterns associated with poor results. The observed gait patterns suggest that changes can be addressed by physical therapy and customized orthoses to improve overall outcome.
2020, Schwartz et al. ‘Fractures of the Talus: Current Concepts’.Foot & Ankle Orthopaedics 2020, Vol. 5(1) 1-10.
DOI: 10.1177/2473011419900766
I recommend this as a good recent review.
Overall Summary. The talus is definitely a bone you don’t want to break! Apart from minor avulsions etc, it takes quite a lot of force to break it; comminution, associated fractures & dislocations are common. All these injuries apart from the Type 1 fractures require significant urgent attention. The prognosis is significantly affected by initial displacement, so even with excellent treatment there is a significant incidence of fair or poor results because the blood supply to the talus makes it vulnerable to AVN. Post-Traumatic Arthritis (PTA) is common. There is usually a significant level of disability.
Great stuff Richard. I believe Crawford Adams coined the phrase the RAF arthrodesis for PTOA following aviators astragalus and the RAF called it the Crawford Adams arthrodesis.