588381
research-article2015
FAIXXX10.1177/1071100715588381Foot & Ankle InternationalJung et al
Article
Concomitant Ankle Injuries Associated With Tibial Shaft Fractures
Foot & Ankle International® 1–6 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1071100715588381 fai.sagepub.com
Ki Jin Jung, MD1, Chin Youb Chung, MD, PhD2, Moon Seok Park, MD, PhD2, Myung Ki Chung, MD2, Dong Yeon Lee, MD, PhD3, Seungbum Koo, PhD4, and Kyoung Min Lee, MD, PhD2
Abstract Background: Ankle injuries associated with tibial shaft fractures can cause postoperative ankle pain and stiffness even when satisfactory bony union has been achieved. Although several previous studies have described these injuries, they have not been clearly defined or classified in terms of ankle injury type or need for surgical fixation. Methods: Seventy-one consecutive patients (mean ± SD age, 48.3 ± 16.7 years; 37 men and 34 women) with tibial shaft fractures who underwent computed tomography examination were included. Data were collected including age, sex, body mass index, fracture location of the tibia and fibula (in percentile of length), tibial fracture shape (spiral, oblique, transverse), presence and pattern of concomitant ankle injuries (on the distal tibial articular surface), and necessity for surgical fixation of ankle injuries. Factors associated with concomitant ankle injuries associated with tibial shaft fractures were analyzed by logistic regression analysis. Results: A total of 47 (64.7%) of the 71 tibial shaft fractures involved concomitant ankle injuries, including 8 cases of combined lateral malleolar fracture, posterior malleolar fracture, and anterior inferior tibiofibular ligament (AITFL) avulsion fracture; 9 cases of combined posterior malleolar fracture and AITFL avulsion fracture; 6 cases of combined lateral malleolar fracture and posterior malleolar fracture; 1 case of combined lateral malleolar fracture and AITFL avulsion fracture; 10 cases of posterior malleolar fracture; 7 cases of lateral malleolar fracture; 5 cases of AITFL avulsion fracture; and 1 unclassified fracture. Of these, 34 of the ankle injuries required surgical fixation. Spiral-type tibial shaft fracture was significantly associated with concomitant ankle injury (P = .001). Conclusions: Orthopaedic surgeons should be aware that tibial shaft fractures, especially spiral-type fractures, are frequently associated with ankle injuries, such as lateral malleolar fractures, posterior malleolar fractures, and AITFL avulsion fractures. A considerable portion of these cases may necessitate surgical fixation. We recommend all spiral-type tibial shaft fractures routinely undergo computed tomography examination. Level of Evidence: Level III, comparative series. Keywords: concomitant ankle injuries, spiral fracture, tibial shaft fracture, computed tomography Tibial shaft fracture is a common orthopaedic injury requiring surgical treatment. The operative outcome of tibial shaft fractures is usually satisfactory, with a high union rate (over 90%)3; however, some patients complain of unexplained ankle pain and stiffness, even when complete union of the tibia shaft has been achieved. Previous studies have reported that ankle injuries, both occult and apparent, may accompany tibial shaft fractures.1,5-9 Posterior malleolar fractures have been reported as the most frequent ankle injuries associated with tibial shaft fracture, and distal third tibial shaft fractures are the most common type of tibial fractures to involve concurrent ankle injuries.5,6,8,9 Concomitant ankle injuries can be overlooked if patients do not complain of specific ankle pain at the time of injury.9 However, if not appropriately managed, such an injury could
cause long-term sequelae or discomfort of the ankle joint.9 Thus, orthopaedic surgeons managing tibial shaft fractures should be more alert to detect concomitant ankle injuries. The present study aimed to investigate concomitant ankle 1
Department of Orthopaedic Surgery, Soonchunhyang University Cheonan Hospital, Cheonan, Korea 2 Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Korea 3 Department of Orthopaedic Surgery, Seoul National University Hospital, Seoul, Korea 4 School of Mechanical Engineering, Chung-Ang University, Seoul, Korea Corresponding Author: Kyoung Min Lee, MD, PhD, Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, 300 Gumi-Dong, Bundang-Gu, Sungnam, Kyungki 463-707, Korea. Email: [email protected]
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injuries associated with tibial shaft fractures, and it further classified these ankle injuries according to type and surgical indication using computed tomography (CT).
Methods This study was approved by the institutional board at our hospital, and informed consent was waived because of the retrospective nature of the study. All consecutive patients with tibial shaft fractures who were evaluated in our emergency room underwent CT examination between 2009 and 2014. The data were retrospectively collected. Exclusion criteria were as follows: fractures primarily involving the knee joint (tibial plateau fractures); fractures primarily involving the ankle joint (uni-, bi-, and trimalleolar ankle fractures); old fractures or nonunions; congenital anomaly, neuromuscular disease, infection, tumors, and any other diseases that could change the normal anatomy of musculoskeletal structures; crush injuries; bilateral tibial fractures; and CT images that did not include the whole length of the tibia and fibula. A total of 71 patients with tibial shaft fractures who underwent CT examination were ultimately included and analyzed. Their mean ± SD age was 48.3 ± 16.7 years, and there were 37 men and 34 women. Thirty-two fractures were on the right side, and 39 were on the left. Body mass index was 24.1 ± 2.9 kg/m2 for men and 22.8 ± 2.7 kg/m2 for women.
Figure 1. The location of tibial fracture was defined as the midpoint of the fracture line, which was calculated as the percentile between the ankle joint line and knee joint line: A / (A + B) × 100. The location of fibular fracture was calculated using the same method between the distal and proximal tips of fibula.
Presence of Ankle Joint Involvement, Type of Ankle Injury, and Surgical Indication
CT Examination Lower leg CT examinations were performed using Brilliance iCT (Philips Healthcare, Cleveland, OH, USA) with 120 kVP, 150-mm field of view, and 0.5-mm slice thickness. The scanner was calibrated daily. CT examinations were taken with the patient in the supine position. Multidetector CT and 3-dimensional reconstruction were performed. CT images were retrieved using a picture archiving and communication system, and measurements were subsequently carried out on IMPAX software (Agfa Healthcare, Mortsel, Belgium).
Fracture Location and Shape The tibial fracture location was measured on 3-dimensional CT images. The midpoint of the fracture line was defined as the fracture location, and the point was calculated as the percentile between the ankle joint line and knee joint line, where the ankle joint line was 0% and the knee joint line was 100%. Similarly, fibular fracture location was calculated as the percentile between the distal tip and proximal tip of the fibula (Figure 1). Tibial fracture shape was categorized into spiral, oblique, and transverse types (Figure 2). When the fracture was comminuted or had a butterfly fragment, the primary or main fracture line was identified and categorized.
Concomitant ankle injuries with tibial shaft fractures were evaluated on axial, sagittal, and coronal planes. The ankle injuries involving the distal tibial articular surface and lateral malleolar fracture were recorded as concomitant ankle injuries. Fibular fracture lines located in the distal third of the fibula were defined as lateral malleolar fractures. Generally, distal articular surface ankle injuries associated with tibial shaft fractures were classified as posterior malleolar fracture or anterior inferior tibiofibular ligament (AITFL) avulsion fracture or lateral malleolar fracture. Surgical fixation was considered necessary for ankle injuries (distal tibial articular surface) if the fragment involved over 25% of the articular surface and the displacement of the fragment exceeded 2 mm.
Statistics Descriptive statistics including mean, standard deviation, and proportions were calculated. The 2 groups (concurrent ankle injury and without ankle injury) were compared using a t test and a chi-square test according to the data characteristics. To identify the factors that significantly contributed to concurrent ankle injuries with tibial shaft fractures, binary logistic regression was performed. Statistical
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Jung et al Table 1. Data Summary.a Patients Age, y Sex Male Female Side Right Left Body mass index, kg/m2 Fracture location, % Tibial Location Tibial fracture shape Spiral Oblique Transverse
71 48.3 ± 16.7 37 (52.1) 34 (47.9) 32 (45.1) 39 (54.9) 23.5 ± 2.9 32.5 ± 14.3 57.7 ± 26.8 46 18 7
a
Data are presented as n (%) or mean ± SD.
Figure 2. Tibial fracture shape was categorized into transverse (A), oblique (B), and spiral (C) fractures.
analyses were conducted with SPSS (v 20.0; IBM Co, Chicago, IL) and R (v 2.15.1). All statistics were 2-tailed, and P < .05 was considered significant.
Results The mean location of the 71 tibia shaft fractures was 32.5% ± 14.3%, and that of 67 fibular fractures was 57.7% ± 26.8%. Four patients had isolated tibial shaft fractures without concurrent fibular fractures. The most common tibial shaft fracture shape was spiral, in 46 patients (64.8%). Eighteen patients (25.4%) had oblique fractures, and 7 (9.8%) had transverse fractures (Table 1). Of the 71 patients with tibial shaft fractures, 47 (64.7%) were found to have concomitant ankle injuries. Eight patients had combined lateral malleolar fracture, posterior malleolar fracture, and AITFL avulsion fractures. Nine patients had both posterior malleolar fracture and AITFL avulsion fractures (Figure 3). Six patients had both lateral malleolar fracture and posterior malleolar fracture. One patient had both lateral malleolar fracture and AITFL avulsion fracture. Ten patients had only posterior malleolar fractures (Figure 4). Seven patients had only lateral malleolar fractures. Five patients had only AITFL avulsion fractures and 1 patient had an unclassified fracture, which was a very large posterior malleolar fracture extending to the medial malleolus with lateral malleolar fracture. Of these, 34 cases underwent surgical fixation. Of the 46 patients with spiral tibial fractures, 41 (89.1%) had concomitant ankle injuries, 30 of which required surgical fixation. Of the 18 patients with oblique tibial fractures, 6 (33.3%) had concomitant ankle injuries, 4 of which
Figure 3. Ankle injuries classified as combined posterior malleolar fracture (black arrow) and anterior inferior tibiofibular ligament avulsion fracture (black arrowhead) on computed tomography images. Anterior inferior tibiofibular ligament avulsion fracture could be a small fragment (A) or a fragment involving a considerable portion of distal tibial articular surface (B).
required surgical fixation. There were no instances of concomitant ankle injury in the 8 transverse tibial fractures (Figure 5). Tibial fracture location (P < .001) and tibial fracture shape (P < .001) were found to significantly differ between tibial fractures with ankle injuries and those without ankle injuries (Table 2). Binary logistic regression analysis showed that tibial fracture shape was the only significant factor associated with concomitant ankle injuries in tibial shaft fractures (P = .001; Table 3).
Discussion This study showed that tibial shaft fractures were frequently associated with ankle injuries, constituting 64.7%
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Figure 4. Ankle injuries classified as posterior malleolar fracture (black arrow). Posterior malleolar fragment could be small such that it does not need surgical fixation (A) or large such that does need surgical fixation (B; ie, it involves more than 25% of the distal tibial articular surface and is displaced more than 2 mm).
Figure 5. According to tibial fracture shape, our cohort consisted of 46 spiral, 18 oblique, and 7 transverse fractures.
of the tibial shaft fractures in our study cohort. Of these cases, 72.3% needed surgical treatment for ankle injuries along with fixation of tibial shaft fractures. Most of the ankle injuries associated with tibial shaft fractures were lateral malleolar fracture, posterior malleolar fractures, and AITFL avulsion fractures. Spiral-type tibial shaft fractures were significantly associated with concomitant ankle injuries. Some limitations should be addressed before discussing the study results in detail. First, the number of cases is somewhat small to generalize the study results. Second, concomitant ankle injuries were confined to bony structures because this study was based on CT examination. Soft tissue injuries, which require magnetic resonance imaging to detect, were not evaluated.
Previous studies investigating concurrent ankle injuries with tibial shaft fractures have reported that distal third tibial shaft fractures or spiral tibial fractures were associated with posterior malleolar fractures,6,8-10 which is consistent with our study results. We found that spiral fracture was associated with ankle injuries and that the mean location of spiral tibial shaft fractures with concurrent ankle injuries was 28.5%. Previous studies also suggested a relationship of tibial shaft fracture with (1) medial and lateral malleolar fractures and (2) syndesmosis injuries,7-9 which is similar to our results. However, we could observe only 1 case of atypical medial malleolar fracture that was continuous with a posterior malleolar fracture. We believe the reason to be the different characteristics of our study cohort compared to those of previous studies that included direct and crush injuries.7-9 Our study essentially investigated the tibial shaft fractures caused by indirect injury. In this study, we defined ankle injuries as involving the lateral malleolar fracture and distal tibial articular surface and systematically categorized ankle injuries into posterior malleolar and AITFL avulsion fracture. We statistically analyzed the factors associated with concomitant ankle injuries in tibial shaft fractures. The most common type of tibial shaft fracture in our cohort was distal third spiral tibial fractures with proximal third fibular fractures, which composed 28 of the 46 spiral tibial fractures. This type of spiral tibial fracture is believed to result from torsional force on nearly the entire lower leg, and the distance between the tibial and fibular fractures represents the extent of tissue damage. This extensive torsional force could increase the possibility of concomitant ankle injuries,9 exerting tension force on the AITFL attachment and compression or shear force on the posterior malleolus via the talus at the ankle joint. However, this hypothesis requires further investigation in a biomechanical study. Concurrent fibular fracture could indicate the amount of exerted force and extent of tissue damage. Of the 4 tibial shaft fractures without fibular fractures in this cohort, 3 did not have concomitant ankle injuries, and the remaining 1 had only a small AITFL avulsion fracture that did not require surgical fixation. The reported incidence of concomitant ankle injuries in tibial shaft fractures has increased with the introduction of additional CT examinations beyond simple radiographs.1,2,6-8,11 CT is believed to have increased the sensitivity of detecting occult ankle injury detection in tibial fractures. Although the clinical significance of concomitant occult ankle injuries has not been clarified in terms of treatment plan and prognosis, these injuries need to be detected preoperatively and managed appropriately using CT to reduce possible long-term sequelae. Undisplaced occult ankle fractures, if neglected, could risk being further displaced intraoperatively during intramedullary nail fixation,4 and postoperative rehabilitation strategies might change
Downloaded from fai.sagepub.com at CAMBRIDGE UNIV LIBRARY on August 7, 2015
5
Jung et al Table 2. Comparison Between Groups: Concurrent Ankle Injury and Without Ankle Injury.a Concurrent Ankle Injury
Without Ankle Injury
P Value
47 53.7 ± 14.5
24 51.2 ± 19.7
22 25
15 9
23 24 23.8 ± 2.9
9 15 22.9 ± 2.9
27.6 ± 6.8 54.8 ± 29.2 31.6 ± 23.5
42.2 ± 19.5 63.9 ± 19.7 26.5 ± 21.2
NA .541 .211 .360 .241
research-article2015
FAIXXX10.1177/1071100715588381Foot & Ankle InternationalJung et al
Article
Concomitant Ankle Injuries Associated With Tibial Shaft Fractures
Foot & Ankle International® 1–6 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1071100715588381 fai.sagepub.com
Ki Jin Jung, MD1, Chin Youb Chung, MD, PhD2, Moon Seok Park, MD, PhD2, Myung Ki Chung, MD2, Dong Yeon Lee, MD, PhD3, Seungbum Koo, PhD4, and Kyoung Min Lee, MD, PhD2
Abstract Background: Ankle injuries associated with tibial shaft fractures can cause postoperative ankle pain and stiffness even when satisfactory bony union has been achieved. Although several previous studies have described these injuries, they have not been clearly defined or classified in terms of ankle injury type or need for surgical fixation. Methods: Seventy-one consecutive patients (mean ± SD age, 48.3 ± 16.7 years; 37 men and 34 women) with tibial shaft fractures who underwent computed tomography examination were included. Data were collected including age, sex, body mass index, fracture location of the tibia and fibula (in percentile of length), tibial fracture shape (spiral, oblique, transverse), presence and pattern of concomitant ankle injuries (on the distal tibial articular surface), and necessity for surgical fixation of ankle injuries. Factors associated with concomitant ankle injuries associated with tibial shaft fractures were analyzed by logistic regression analysis. Results: A total of 47 (64.7%) of the 71 tibial shaft fractures involved concomitant ankle injuries, including 8 cases of combined lateral malleolar fracture, posterior malleolar fracture, and anterior inferior tibiofibular ligament (AITFL) avulsion fracture; 9 cases of combined posterior malleolar fracture and AITFL avulsion fracture; 6 cases of combined lateral malleolar fracture and posterior malleolar fracture; 1 case of combined lateral malleolar fracture and AITFL avulsion fracture; 10 cases of posterior malleolar fracture; 7 cases of lateral malleolar fracture; 5 cases of AITFL avulsion fracture; and 1 unclassified fracture. Of these, 34 of the ankle injuries required surgical fixation. Spiral-type tibial shaft fracture was significantly associated with concomitant ankle injury (P = .001). Conclusions: Orthopaedic surgeons should be aware that tibial shaft fractures, especially spiral-type fractures, are frequently associated with ankle injuries, such as lateral malleolar fractures, posterior malleolar fractures, and AITFL avulsion fractures. A considerable portion of these cases may necessitate surgical fixation. We recommend all spiral-type tibial shaft fractures routinely undergo computed tomography examination. Level of Evidence: Level III, comparative series. Keywords: concomitant ankle injuries, spiral fracture, tibial shaft fracture, computed tomography Tibial shaft fracture is a common orthopaedic injury requiring surgical treatment. The operative outcome of tibial shaft fractures is usually satisfactory, with a high union rate (over 90%)3; however, some patients complain of unexplained ankle pain and stiffness, even when complete union of the tibia shaft has been achieved. Previous studies have reported that ankle injuries, both occult and apparent, may accompany tibial shaft fractures.1,5-9 Posterior malleolar fractures have been reported as the most frequent ankle injuries associated with tibial shaft fracture, and distal third tibial shaft fractures are the most common type of tibial fractures to involve concurrent ankle injuries.5,6,8,9 Concomitant ankle injuries can be overlooked if patients do not complain of specific ankle pain at the time of injury.9 However, if not appropriately managed, such an injury could
cause long-term sequelae or discomfort of the ankle joint.9 Thus, orthopaedic surgeons managing tibial shaft fractures should be more alert to detect concomitant ankle injuries. The present study aimed to investigate concomitant ankle 1
Department of Orthopaedic Surgery, Soonchunhyang University Cheonan Hospital, Cheonan, Korea 2 Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Korea 3 Department of Orthopaedic Surgery, Seoul National University Hospital, Seoul, Korea 4 School of Mechanical Engineering, Chung-Ang University, Seoul, Korea Corresponding Author: Kyoung Min Lee, MD, PhD, Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, 300 Gumi-Dong, Bundang-Gu, Sungnam, Kyungki 463-707, Korea. Email: [email protected]
Downloaded from fai.sagepub.com at CAMBRIDGE UNIV LIBRARY on August 7, 2015
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Foot & Ankle International
injuries associated with tibial shaft fractures, and it further classified these ankle injuries according to type and surgical indication using computed tomography (CT).
Methods This study was approved by the institutional board at our hospital, and informed consent was waived because of the retrospective nature of the study. All consecutive patients with tibial shaft fractures who were evaluated in our emergency room underwent CT examination between 2009 and 2014. The data were retrospectively collected. Exclusion criteria were as follows: fractures primarily involving the knee joint (tibial plateau fractures); fractures primarily involving the ankle joint (uni-, bi-, and trimalleolar ankle fractures); old fractures or nonunions; congenital anomaly, neuromuscular disease, infection, tumors, and any other diseases that could change the normal anatomy of musculoskeletal structures; crush injuries; bilateral tibial fractures; and CT images that did not include the whole length of the tibia and fibula. A total of 71 patients with tibial shaft fractures who underwent CT examination were ultimately included and analyzed. Their mean ± SD age was 48.3 ± 16.7 years, and there were 37 men and 34 women. Thirty-two fractures were on the right side, and 39 were on the left. Body mass index was 24.1 ± 2.9 kg/m2 for men and 22.8 ± 2.7 kg/m2 for women.
Figure 1. The location of tibial fracture was defined as the midpoint of the fracture line, which was calculated as the percentile between the ankle joint line and knee joint line: A / (A + B) × 100. The location of fibular fracture was calculated using the same method between the distal and proximal tips of fibula.
Presence of Ankle Joint Involvement, Type of Ankle Injury, and Surgical Indication
CT Examination Lower leg CT examinations were performed using Brilliance iCT (Philips Healthcare, Cleveland, OH, USA) with 120 kVP, 150-mm field of view, and 0.5-mm slice thickness. The scanner was calibrated daily. CT examinations were taken with the patient in the supine position. Multidetector CT and 3-dimensional reconstruction were performed. CT images were retrieved using a picture archiving and communication system, and measurements were subsequently carried out on IMPAX software (Agfa Healthcare, Mortsel, Belgium).
Fracture Location and Shape The tibial fracture location was measured on 3-dimensional CT images. The midpoint of the fracture line was defined as the fracture location, and the point was calculated as the percentile between the ankle joint line and knee joint line, where the ankle joint line was 0% and the knee joint line was 100%. Similarly, fibular fracture location was calculated as the percentile between the distal tip and proximal tip of the fibula (Figure 1). Tibial fracture shape was categorized into spiral, oblique, and transverse types (Figure 2). When the fracture was comminuted or had a butterfly fragment, the primary or main fracture line was identified and categorized.
Concomitant ankle injuries with tibial shaft fractures were evaluated on axial, sagittal, and coronal planes. The ankle injuries involving the distal tibial articular surface and lateral malleolar fracture were recorded as concomitant ankle injuries. Fibular fracture lines located in the distal third of the fibula were defined as lateral malleolar fractures. Generally, distal articular surface ankle injuries associated with tibial shaft fractures were classified as posterior malleolar fracture or anterior inferior tibiofibular ligament (AITFL) avulsion fracture or lateral malleolar fracture. Surgical fixation was considered necessary for ankle injuries (distal tibial articular surface) if the fragment involved over 25% of the articular surface and the displacement of the fragment exceeded 2 mm.
Statistics Descriptive statistics including mean, standard deviation, and proportions were calculated. The 2 groups (concurrent ankle injury and without ankle injury) were compared using a t test and a chi-square test according to the data characteristics. To identify the factors that significantly contributed to concurrent ankle injuries with tibial shaft fractures, binary logistic regression was performed. Statistical
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3
Jung et al Table 1. Data Summary.a Patients Age, y Sex Male Female Side Right Left Body mass index, kg/m2 Fracture location, % Tibial Location Tibial fracture shape Spiral Oblique Transverse
71 48.3 ± 16.7 37 (52.1) 34 (47.9) 32 (45.1) 39 (54.9) 23.5 ± 2.9 32.5 ± 14.3 57.7 ± 26.8 46 18 7
a
Data are presented as n (%) or mean ± SD.
Figure 2. Tibial fracture shape was categorized into transverse (A), oblique (B), and spiral (C) fractures.
analyses were conducted with SPSS (v 20.0; IBM Co, Chicago, IL) and R (v 2.15.1). All statistics were 2-tailed, and P < .05 was considered significant.
Results The mean location of the 71 tibia shaft fractures was 32.5% ± 14.3%, and that of 67 fibular fractures was 57.7% ± 26.8%. Four patients had isolated tibial shaft fractures without concurrent fibular fractures. The most common tibial shaft fracture shape was spiral, in 46 patients (64.8%). Eighteen patients (25.4%) had oblique fractures, and 7 (9.8%) had transverse fractures (Table 1). Of the 71 patients with tibial shaft fractures, 47 (64.7%) were found to have concomitant ankle injuries. Eight patients had combined lateral malleolar fracture, posterior malleolar fracture, and AITFL avulsion fractures. Nine patients had both posterior malleolar fracture and AITFL avulsion fractures (Figure 3). Six patients had both lateral malleolar fracture and posterior malleolar fracture. One patient had both lateral malleolar fracture and AITFL avulsion fracture. Ten patients had only posterior malleolar fractures (Figure 4). Seven patients had only lateral malleolar fractures. Five patients had only AITFL avulsion fractures and 1 patient had an unclassified fracture, which was a very large posterior malleolar fracture extending to the medial malleolus with lateral malleolar fracture. Of these, 34 cases underwent surgical fixation. Of the 46 patients with spiral tibial fractures, 41 (89.1%) had concomitant ankle injuries, 30 of which required surgical fixation. Of the 18 patients with oblique tibial fractures, 6 (33.3%) had concomitant ankle injuries, 4 of which
Figure 3. Ankle injuries classified as combined posterior malleolar fracture (black arrow) and anterior inferior tibiofibular ligament avulsion fracture (black arrowhead) on computed tomography images. Anterior inferior tibiofibular ligament avulsion fracture could be a small fragment (A) or a fragment involving a considerable portion of distal tibial articular surface (B).
required surgical fixation. There were no instances of concomitant ankle injury in the 8 transverse tibial fractures (Figure 5). Tibial fracture location (P < .001) and tibial fracture shape (P < .001) were found to significantly differ between tibial fractures with ankle injuries and those without ankle injuries (Table 2). Binary logistic regression analysis showed that tibial fracture shape was the only significant factor associated with concomitant ankle injuries in tibial shaft fractures (P = .001; Table 3).
Discussion This study showed that tibial shaft fractures were frequently associated with ankle injuries, constituting 64.7%
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Foot & Ankle International
Figure 4. Ankle injuries classified as posterior malleolar fracture (black arrow). Posterior malleolar fragment could be small such that it does not need surgical fixation (A) or large such that does need surgical fixation (B; ie, it involves more than 25% of the distal tibial articular surface and is displaced more than 2 mm).
Figure 5. According to tibial fracture shape, our cohort consisted of 46 spiral, 18 oblique, and 7 transverse fractures.
of the tibial shaft fractures in our study cohort. Of these cases, 72.3% needed surgical treatment for ankle injuries along with fixation of tibial shaft fractures. Most of the ankle injuries associated with tibial shaft fractures were lateral malleolar fracture, posterior malleolar fractures, and AITFL avulsion fractures. Spiral-type tibial shaft fractures were significantly associated with concomitant ankle injuries. Some limitations should be addressed before discussing the study results in detail. First, the number of cases is somewhat small to generalize the study results. Second, concomitant ankle injuries were confined to bony structures because this study was based on CT examination. Soft tissue injuries, which require magnetic resonance imaging to detect, were not evaluated.
Previous studies investigating concurrent ankle injuries with tibial shaft fractures have reported that distal third tibial shaft fractures or spiral tibial fractures were associated with posterior malleolar fractures,6,8-10 which is consistent with our study results. We found that spiral fracture was associated with ankle injuries and that the mean location of spiral tibial shaft fractures with concurrent ankle injuries was 28.5%. Previous studies also suggested a relationship of tibial shaft fracture with (1) medial and lateral malleolar fractures and (2) syndesmosis injuries,7-9 which is similar to our results. However, we could observe only 1 case of atypical medial malleolar fracture that was continuous with a posterior malleolar fracture. We believe the reason to be the different characteristics of our study cohort compared to those of previous studies that included direct and crush injuries.7-9 Our study essentially investigated the tibial shaft fractures caused by indirect injury. In this study, we defined ankle injuries as involving the lateral malleolar fracture and distal tibial articular surface and systematically categorized ankle injuries into posterior malleolar and AITFL avulsion fracture. We statistically analyzed the factors associated with concomitant ankle injuries in tibial shaft fractures. The most common type of tibial shaft fracture in our cohort was distal third spiral tibial fractures with proximal third fibular fractures, which composed 28 of the 46 spiral tibial fractures. This type of spiral tibial fracture is believed to result from torsional force on nearly the entire lower leg, and the distance between the tibial and fibular fractures represents the extent of tissue damage. This extensive torsional force could increase the possibility of concomitant ankle injuries,9 exerting tension force on the AITFL attachment and compression or shear force on the posterior malleolus via the talus at the ankle joint. However, this hypothesis requires further investigation in a biomechanical study. Concurrent fibular fracture could indicate the amount of exerted force and extent of tissue damage. Of the 4 tibial shaft fractures without fibular fractures in this cohort, 3 did not have concomitant ankle injuries, and the remaining 1 had only a small AITFL avulsion fracture that did not require surgical fixation. The reported incidence of concomitant ankle injuries in tibial shaft fractures has increased with the introduction of additional CT examinations beyond simple radiographs.1,2,6-8,11 CT is believed to have increased the sensitivity of detecting occult ankle injury detection in tibial fractures. Although the clinical significance of concomitant occult ankle injuries has not been clarified in terms of treatment plan and prognosis, these injuries need to be detected preoperatively and managed appropriately using CT to reduce possible long-term sequelae. Undisplaced occult ankle fractures, if neglected, could risk being further displaced intraoperatively during intramedullary nail fixation,4 and postoperative rehabilitation strategies might change
Downloaded from fai.sagepub.com at CAMBRIDGE UNIV LIBRARY on August 7, 2015
5
Jung et al Table 2. Comparison Between Groups: Concurrent Ankle Injury and Without Ankle Injury.a Concurrent Ankle Injury
Without Ankle Injury
P Value
47 53.7 ± 14.5
24 51.2 ± 19.7
22 25
15 9
23 24 23.8 ± 2.9
9 15 22.9 ± 2.9
27.6 ± 6.8 54.8 ± 29.2 31.6 ± 23.5
42.2 ± 19.5 63.9 ± 19.7 26.5 ± 21.2
NA .541 .211 .360 .241
