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The primary objective of this study was to observe and compare the radiographic and clinical outcomes among three different approaches which are anteromedial, anterolateral and combined approach in patients of talar neck fractures. The secondary objective was to observe various complications.
Material and method
A total of 30 patients underwent open reduction and internal fixation (ORIF) from September 2018 to march 2020 were selected retrospectively. 10 patients were there in each group. Talar neck fractures were classified according to Hawkins classification. All patients underwent ORIF with 4 mm Herbert screws. The follow-up examination included radiological evaluation, clinical and functional outcomes according to American Orthopaedic Foot and Ankle Society hind-foot score (AOFAS).
Results
30 patients were followed up for an average of 20.85 months (range 16–24). The mean time to bony union was 17.25 weeks, 17.35 weeks and 15.92 weeks in groups operated with anteromedial approach, anterolateral approach and combined approach respectively. The mean AOFAS hind-foot score was 76.34, 77.16 and 78.34 at 18th month follow-up in all three groups respectively. In each group, 1 patient had deep wound infection and 2 patients had superficial wound infection. Subtalar arthritis was the most common complication.
Conclusion
There is no significant difference between the three groups in terms of AOFAS hind-foot score, further combined approach provides better visualization of talus fractures and early bony union but it takes longer duration of surgery with increased post-operative complications in comparison with other two groups.
Fractures of talus are infrequent and deeming for approximately 0.1% of all fractures. Fractures and dislocations of the talus are challenging injuries to orthopaedic trauma surgeons due to its unique structure.
Talus has characteristic tenuous blood supply with tarsal canal artery (branch of posterior tibial artery) supplies the most of the talar body, whereas branches of dorsalis pedis artery and sinus tarsi artery supplies talar head and neck. Talus is mostly covered by articular cartilage for about 70% without any muscle attachment. Talus also gets blood supply from joint capsules and thickened ligaments of the talus, therefore any capsular disruption, soft tissue handling, initial fracture displacement and timing of surgery are all potential factors affecting blood supply preceding to avascular necrosis (AVN) of talus.
They occur when a person sustains forced dorsiflexion of the foot due to high velocity trauma as in parachutists and pilots of the Royal Air Force who sustained these injuries upon impact with ground and termed as aviator's astragalus.
In cancellous bones like talus which heals by endosteal type of callus and not visible on x-ray film therefore fracture healing is assessed by clinical factors like absence of pain on movement and during weight bearing with absence of tenderness on palpation.
Complications such as osteonecrosis (AVN) of talus and posttraumatic arthritis such as subtalar arthritis, tibiotalar arthritis and talonavicular arthritis are common in talar injuries. Other complications such as mal-union and non-union are less frequently seen.
The evidence of preserved vascularity of the talus seen in radiograph consisting of patchy subchondral osteopenia which is seen at 6–8 weeks after the injury is termed as Hawkins sign. The presence of Hawkins sign is a reliable predictor of AVN talus.
Fractures of talus can be fixed using K-wires, cannulated screws and plates, but in our study, we used cannulated screws in all patients. In our study talus neck fractures are classified according to Hawkins classification modified by Canale and Kelly.
Talus body fractures are basically intra-articular including fractures of the talar dome, lateral and posterior process of the talar body and classified according to Sneppen classification.
To our knowledge there are few studies engaging different surgical approaches in the treatment of talus fractures, so our study was conducted to compare clinical outcome and postoperative complications among three surgical approaches namely anteromedial, anterolateral and combined approach in the treatment of talus neck fractures.
2. Materials and methods
A comparative retrospective study was conducted at level 1 trauma centre involving consecutive 30 patients from September 2018 to March 2020. All patients were divided into three groups with 10 patients in each group based on surgical approach method (group A – anteromedial approach, group B- anterolateral approach, group C – anteromedial and anterolateral approach). Allocation to the particular group was done by the patient after informed consent. Randomization done by a person not involving in operation team, by choosing a sealed envelope out of A/B/C signifying a particular approach. Further choosing an envelope is done by patient himself before the surgery. All surgeries are done by different surgeons of above the level of assistant professors in a tertiary care centre. Patients with talus neck fractures, compound fractures up-to grade 1 of Gustilo-Anderson classification and patients aged above 18 years were included. Patients with associated fractures like vertebrae, medial malleolus, metatarsals and calcaneus were also included. Patients with talus body, uncontrolled diabetes mellitus, psychiatric illness and severe cardiac illness were excluded. Appropriate anteroposterior (AP) radiograph, lateral radiograph, Canale view and CT scan were taken and the limb was immobilized in below knee slab.
2.1 Surgical technique
All patients were given preoperative antibiotics. All cases were managed under spinal anaesthesia in supine position. An image intensifier with c-arm was used in all cases to provide fluoroscopic guidance.
2.2 Anteromedial approach
An incision of 10 cm long, beginning at the lower third of the leg 1 cm lateral to the anterior crest of the tibia, running downwards and medially to midway between the tip of the medial malleolus and the navicular tubercle was given. Malleolar osteotomy was done to improve the exposure if required. The fracture was fixed with two Kirschner wires for temporary reduction. Then 4 mm Herbert screws or cannulated screws were used in either anterior to posterior direction or vice-versa. The osteotomised medial malleolus was fixed with k-wire Tension band wiring (TBW). The saphenous nerve and vein were at risk during this procedure.
2.3 Anterolateral approach
A curved incision of 15 cm long on anterolateral aspect of ankle, starting 5 cm proximal to the ankle joint and 2 cm anterior to the anterior border of the fibula was given. Then curving the incision down 2 cm crossing the ankle joint medial to the lateral malleolus and terminating 2 cm medial to fifth metatarsal base. In the deep dissection superior and inferior retinacula were cut then extensor digitorum brevis was retracted medially. Fat pad was preserved to prevent ugly skin dimple and to improve wound healing.
2.4 Combined approach
Here both above mentioned anteromedial and anterolateral approaches were used.
2.5 Postoperative evaluation
A well-padded below knee slab was used in ankle neutral alignment, strict limb elevation and active toe movements advised. Sutures were removed after 14 days of surgery. Patients were followed up both clinically and radiologically at 4, 8 and 16 weeks and every 6 months thereafter. Data was collected by verbal communication, clinical examination and radiographic features. Patients were assessed for AOFAS hind-foot score,
bony union and complications regularly. Regular physiotherapy was conducted simultaneously at appropriate follow-ups with help of dedicated physiotherapy team. Partial weight bearing lasted for about 12 weeks. The range of motion and any deformity were assessed. On periodic radiographs AVN of talus, ankle arthritis, and subtalar arthritis, non-union and mal-union were recorded. AOFAS hind-foot survey included total 9 questions related to pain (1 question; 40 points), function (7 questions; 50 points) and alignment (1 question; 10 points). A score of 90–100 was considered as excellent result, 75–89 as good, 50–74 as fair and less than 49 as poor outcome. Statistical analysis was performed with the SPSS version 21 for Windows statistical software package (SPSS inc., Chicago, IL, USA). The categorical data was compared among groups using Chi square test. The quantitative data was compared by student t-test and ANOVA test. Probability was considered to be significant, if p value is less than 0.05.
3. Results
In this retrospective study of 30 patients who had talus neck fractures and operated by three different approaches. 26 patients were available with us till the final follow-up. In our study mean age was 35.04 years, 34.88 years and 34.32 years in group A, B and C respectively (Range 18–59 years). 73.3% of patients were male and 26.7% were female. 84% of patients suffered fracture due to road traffic accident and rest 16% due to fall from height. 88% of patients had closed fractures and 12% had open fractures. On classifying the patients under Hawkins classification 33%, 44.7%, 17% and 5.3% had Hawkins type 1, 2, 3 and 4 fractures (p-value>0.05). The time interval between the injury and surgery was ranging from 1 to 30 days. The mean time interval was 7.72 days, 8.28 days and 8.32 days in group A, B and C respectively (p > 0.89). The mean operating time was 75, 74.60 and 111.52 min in group A, B and C respectively (p < 0.001). (Fig. 1).
Fig. 1A bar graph showing Interval between injury and surgery (days) and duration (minutes) among different groups.
Mean AOFAS hind-foot score in group A, B and C was 32, 26.64 and 27.52 respectively at 3rd month follow-up. Mean AOFAS hind-foot score in group A, B and C was 45.08, 44.08 and 34.80 respectively at 6th month follow-up. Mean AOFAS hind-foot score in group A, B and C was 64.96, 65.16 and 66.48 respectively at 12th month follow-up (Fig. 2). Mean AOFAS hind-foot score in group A, B and C was 75.23, 78.44 and 77.52 respectively at 18th month follow-up. The results were statistically significant during all assessments except at 12th and 18th month follow-up (p < 0.001). On intra-group comparison, AOFAS hind-foot score was statistically significant in all comparison. The mean time to bony union was 17.25, 17.88 and 15.92 weeks in group A, B and C respectively (p > 0.05). In group A, 2 patients had excellent results, 4 had good results, 16 had fair results and 3 had poor outcome with AOFAS hind-foot grading. In group B, 1 patient had excellent results, 9 had good results, 8 had fair results and 7 had poor outcome with AOFAS hind-foot grading. In group C, 1 patient had excellent results, 9 had good results, 9 had fair results and 6 had poor outcome AOFAS hind-foot grading.
Fig. 2A bar graph showing AOFAS hind-foot score in successive follow-up among different groups.
In group C, 2 patients showed deep wound infection. Further 1 patient in each group showed superficial wound infection. All patients were successfully treated with intravenous antibiotics. Arthritis was the most common complication in our study (28%). Subtalar arthritis (18%) was the most common among arthritis group then tibio-talar arthritis (8%) and talo-navicular arthritis (2%). There were 6 patients with both subtalar and tibio-talar arthritis in our study. AVN of talus (18.7%) was the second most common complication. Arthritis with AVN of talus was seen in 8 patients (Fig. 3, Fig. 4). Non-union (4%) and mal-union (4%) were other late complications.
Fig. 3a) Preoperative AP and lateral radiograph of talus neck fracture (Hawkins type 2) with medial malleolus fracture, b) Post-operative AP and lateral radiograph of talus neck with two 4 mm Herbert screw fixation from posterior to anterior direction with k-wire TBW of medial malleolus.
Fig. 4a) Postoperative radiographs at 6th month follow-up showing united talus and medial malleolus fracture. b) Postoperative radiograph at 12th month follow-up showing changes of osteonecrosis of talus and subtalar arthritis, c) Postoperative radiograph at 18th month follow-up showing marked changes of subtalar arthritis and osteonecrosis.
The treatment of talus fractures usually requires open reduction and internal fixation, as most of the patients develop AVN talus inevitably. The blood vessels supplying to talus gets blocked by contusion and compression by dislocated fractures. Surgical intervention must be meticulous in dissecting the soft tissues and protecting the deltoid ligament especially for deltoid branch of posterior tibial artery.
Basically four surgical approaches are used in talus surgeries namely anteromedial, anterolateral, posteromedial and posterolateral approaches. In our study group C patients were operated with dual approach of anteromedial and anterolateral to maximize anatomical reduction. Many authors recommend dual approach as it exposes both medial and lateral aspect of talus and maintains axial alignment of talus.
Although there is a controversy regarding dual approach in preserving blood supply by meticulous dissection between neurovascular bundle and disruption of blood supply by excessive soft tissue dissection based on operating surgeon.
The incidence of AVN coincides with severity of injury and ranges from 0 to 15% in Hawkins type 1 fractures, 18–71% in Hawkins type 2 fractures to 69–100% in Hawkins type 3 and 4 fractures.
In our study surgical time interval was from 1 to 30 days. Patients with association of multiple fractures like vertebrae and blisters over fractures were operated at late interval. Open fractures were treated within 1–5 days. There was no statistically significant association between timing of surgery and complications. In agreement with many authors surgical timing had no influence on clinical complications like AVN of talus.
Given that, we included talus fractures with other associated fractures surgical timing interval with complications was statistically insignificant was the potential limitation to our study as we did not get results for exclusive talus fractures. In our study we did not use plate fixation or external fixators although few biomechanical studies demonstrated equal rotational resistance and anti-shearing forces comparable to absorbable screws, cancellous screws and cannulated lag screws with plate-screw construct.
Charlson et al. in their biomechanical study showed that plate-screw construct was better than screw only construct in comminuted talus neck fractures.
Herbert screws have advantage of countersinking resulting in minimal damage to joint surface with similar stability compared with plate in talus neck fractures. Further plate application increases the risk of AVN in talus due to stripping of soft tissues.
So we opted for Herbert screw fixation in all patients. Limitations to our study were short duration of follow-up and we used single outcome score to analyse patients. In our study no patients were operated with secondary procedures like arthrodesis or ankle replacement.
5. Conclusion
In the opinion of authors, talar fractures can be managed by different approaches provided operating surgeons have meticulous knowledge about blood supply of talus. There is no significant difference between three different groups in context of AOFAS scoring at final follow-up. A long-term study with large sample size is required to substantiate our results.
Availability of data and material
Not applicable.
Code availability
Not applicable.
Funding
No funding was required in this study.
Authors’ contributions
All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Dr Siddharath Sharanappa Parmeshwar and Dr Shyoji Lal Sharma. The first draft of the manuscript was written by Dr Siddharath Sharanappa Parmeshwar and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.
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