- Email: [email protected]
Syndesmosis Fixation in Unstable Ankle Fractures Using a Partially Threaded 5.0-mm Cannulated Screw
ARTICLE IN PRESS The Journal of Foot & Ankle Surgery ■■ (2017) ■■–■■
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery j o u r n a l h o m e p a g e : w w w. j f a s . o r g
Original Research
Syndesmosis Fixation in Unstable Ankle Fractures Using a Partially Threaded 5.0-mm Cannulated Screw Seung Yeol Lee, MD 1, Sang Young Moon, MD 2, Moon Seok Park, MD 3, Byung Chae Jo, MD 4, Hyunseok Jeong, MD 5, Kyoung Min Lee, MD 6 1Clinical
Associate Professor, Department of Orthopaedic Surgery, Ewha Womans University Mokdong Hospital, Seoul, Republic of Korea Seocho Gangnam Yeok Orthopedic Clinic, Seoul, Republic of Korea Professor, Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Republic of Korea 4 Orthopedist, Department of Orthopaedic Surgery, Seoul Jaeil Hospital, Kyungki, Republic of Korea 5Orthopedist, Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Republic of Korea 6 Clinical Associate Professor, Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Republic of Korea 2Orthopedist, 3Clinical
A R T I C L E
I N F O
Level of Clinical Evidence: 4
Keywords: cannulated screw mortise syndesmosis injury
A B S T R A C T
The present study evaluated the radiographic outcomes of syndesmosis injuries treated with a partially threaded 5.0-mm cannulated screw. The present study included 58 consecutive patients with syndesmosis injuries concurrent with ankle fractures who had undergone operative fixation with a partially threaded 5.0-mm cannulated screw to repair the syndesmosis injury. Radiographic indexes, including the medial clear space, tibiofibular overlap, tibiofibular clear space, and fibular position on the lateral radiograph, were measured on the preoperative, immediate postoperative, and final follow-up radiographs. The measurements were compared between the injured and intact ankles. All preoperative radiographic indexes, including the medial clear space (p < .001), tibiofibular overlap (p < .001), tibiofibular clear space (p < .001), and fibular position on the lateral radiograph (p = .026), were significantly different between the injured and intact ankles. The medial clear space of the injured ankle was significantly wider than that of the intact ankle preoperatively (p < .001) and had become significantly narrower immediately postoperatively (p < .001). Finally, the medial clear space was not significantly different between the injured and intact ankles at the final follow-up examination (p = .522). No screw breakage or repeat fractures were observed. A 5.0-mm partially threaded cannulated screw effectively restored and maintained the normal relationship between the tibia and fibula within the ankle mortise with a low risk of complications. This appears to be an effective alternative technique to treat syndesmosis injuries concurrent with ankle fractures. © 2018 by the American College of Foot and Ankle Surgeons. All rights reserved.
Syndesmosis injuries are relatively common with athletic activity, accounting for ≤18% of all ankle sprains (1). They often occur concurrently with ankle fractures and aggravate the instability of the fracture. The key to treating this type of injury is anatomic reduction and effective stabilization of the ankle mortise, which permits the healing of the syndesmotic ligaments. When uncorrected, chronic syndesmotic instability can result in pain during walking, the ankle “giving way,” and, possibly, early degenerative arthritis (2–6). Financial Disclosure: This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) (NRF-2017R1D1A1B03033913) and the Ministry of Agriculture, Food and Rural Affairs (MAFRA) (117051-3). Conflict of Interest: None reported. Address correspondence to: Kyoung Min Lee, MD, Department of Orthopedic Surgery, Seoul National University Bundang Hospital, 300 Gumi-Dong, Bundang-Gu, Sungnam, Kyungki 463-707, Republic of Korea. E-mail address: [email protected] (K.M. Lee).
Several fixation devices have been used to hold the syndesmosis in position, including syndesmotic screws, bioabsorbable screws, Kirschner wires, and the TightRope system (Arthrex, Naples, FL). Of these, syndesmotic screw fixation is the current standard treatment (7–9). However, no general consensus has been reached regarding the technical aspects of syndesmotic screw fixation. The screw type, screw size, number of cortices engaged, the use of 1 or 2 screws, the position of the ankle during screw fixation, the time required before allowing weightbearing, and the time to screw removal have all been debated. A survey of orthopedic trauma and foot and ankle fellowship directors and members of the Orthopaedic Trauma Association and the American Orthopaedic Foot and Ankle Society found that the most common method for treating syndesmosis injuries involved using one or two 3.5-mm cortical screws engaging 4 cortices, which are removed at 3 months postoperatively (10). However, screw breakage occasionally
1067-2516/$ - see front matter © 2018 by the American College of Foot and Ankle Surgeons. All rights reserved. https://doi.org/10.1053/j.jfas.2017.12.012
ARTICLE IN PRESS 2
S.Y. Lee et al. / The Journal of Foot & Ankle Surgery ■■ (2017) ■■–■■
Fig. 1. Radiographic indexes measured on (A) anteroposterior and (B) lateral view. Medial clear space (a) is the distance between the articular surface of the medial malleolus and the medial talar articular surface. Tibiofibular overlap (b) is the overlap of the lateral malleolus and the anterior tibial tubercle, measured where the overlap is the largest. The tibiofibular clear space (c) is the distance between the medial border of the fibula and the lateral border of the posterior tibia as it extends into the incisura fibularis, measured 1 cm proximal to the plafond. Fibular position on the lateral view (d/e) is the relative position of the fibular center (d) on a length (e) between the anterior and posterior margins of the tibial plafond.
occurs, necessitating removal of the syndesmotic screw before weightbearing (11). Therefore, we modified the syndesmotic screw fixation technique to minimize the risks of breakage. The aim of the present study was to evaluate the radiographic outcomes of syndesmosis injuries treated with a partially threaded 5.0-mm cannulated screw. We hypothesized that the screw could effectively restore and maintain the normal relationship between the tibia and fibula within the ankle mortise.
through the plate hole across the syndesmosis, engaging 4 cortices, 1 to 1.5 cm above the tibia plafond with the ankle in 5° of dorsiflexion. The guide pin facilitated the placement of the screw in the correct position. The deltoid ligament was left unrepaired. Postoperatively, the patients were placed in a well-padded short-leg cast with the ankle in neutral dorsiflexion and instructed to maintain non-weightbearing status for the first 6 weeks. The patients were then placed in a removable short-leg splint, and ankle movement throughout the entire range of motion was encouraged from 2 weeks postoperatively onward. Tolerable and progressive weightbearing was allowed from 6 weeks postoperatively, and then patients were allowed to walk without any limitations.
Patients and Methods
Ankle radiographs of the anteroposterior, mortise, and lateral views were obtained using a UT 2000 x-ray machine (Philips Research, Eindhoven, The Netherlands) at a source-to-image distance of ~100 cm with the patient in the supine position. The radiograph setting depended on the patient’s body size, with a range of 46 to 50 kVp and 4.5 to 5 mA. Radiographic images were retrieved using a picture archiving and communication system, and measurements were subsequently performed using picture archiving and communication system software (IMPAX; Agfa Healthcare, Mortsel, Belgium). Radiographic indexes, including the medial clear space, tibiofibular overlap, tibiofibular clear space, and fibular position on the lateral view (Fig. 1), were measured on the preoperative, immediate postoperative, and final follow-up radiographs for the injured ankle. Those indexes were also measured once for the intact ankle.
The institutional review board of our institute approved the present study. Consecutive patients who had undergone operative treatment with a partially threaded 5.0-mm cannulated screw for syndesmosis injuries concurrent with ankle fractures from May 2009 to December 2013 were enrolled in the present study. All the patients underwent preoperative ankle radiographs, including anteroposterior, lateral, and mortise views. The demographic data, including age, sex, height, and weight, were recorded. The exclusion criteria were as follows: (1) ankle fractures from a direct blow; and (2) abnormal ankle anatomy from a congenital anomaly, previous surgery, trauma, infection, or tumor.
Radiographic Examinations and Measurements
Operative Technique and Postoperative Management
Statistical Analysis
All operations were performed by 2 of us (M.S.P., K.M.L.) with the same treatment policy. The patients underwent operative reduction and internal fixation using a onethird tubular plate and screws for the lateral malleolus and one or two 5.0-mm cannulated screws or tension band wiring for the medial malleolus. The posterior malleolus was fixed using a 5.0-mm cannulated screw if surgical fixation was indicated. Unstable syndesmosis injuries were evaluated using a lateral stress test intraoperatively (12) after all fractures had been internally fixed. Unstable injuries were defined as those with a ≥5 mm tibiofibular clear space on the fluoroscopic lateral stress test (5,13). The syndesmosis was held in place with a large reduction clamp to compress the tibia and fibula. To avoid oblique malreduction, the clamp tips were placed on the lateral malleolar ridge of the fibula, which is the insertion of the peroneal retinaculum, and the center of the anteroposterior width of the medial tibial cortex 10 mm above the ankle joint line. Next, a partially threaded 5.0-mm cannulated screw was placed
Descriptive statistics, including the mean, standard deviation, and proportion, were calculated. A Kolmogorov-Smirnov test was used to verify the normality of the distribution of the continuous variables. Comparisons between the injured and intact ankles were conducted using a t test, paired t test, or Mann-Whitney U test according to the data characteristics. Statistical analyses were conducted using SPSS, version 20.0 (IBM, Armonk, NY) and R, version 2.15.1 (R Foundation, Vienna, Austria). p Values < .05 were considered statistically significant.
Results A total of 58 patients were included in the present study. The mean age of the patients at surgery was 39.9 ± 14.4 years. Of the 58 patients,
ARTICLE IN PRESS S.Y. Lee et al. / The Journal of Foot & Ankle Surgery ■■ (2017) ■■–■■
Table 1 Data summary Variable
Value
Patients Age (y) Sex Male Female Height (cm) Weight (kg) BMI (kg/m2) Follow-up duration (mo) Lauge-Hansen classification SA PER PA PER Fracture extent Unimalleolar Bimalleolar Trimalleolar
58 39.9 ± 14.4 45 13 169.6 ± 8.1 72.2 ± 11.5 25.0 ± 2.8 14.4 ± 5.1 0 32 10 16 12 28 18
Data presented as mean ± standard deviation or n. Abbreviations: BMI, body mass index; PA, pronation-abduction; PER, pronationexternal rotation; SA, supination-adduction; SER, supination-external rotation.
45 were male (78%) and 13 were female (22%; Table 1). The LaugeHansen classification was as follows: supination-external rotation in 32 patients (55%), pronation-abduction in 10 patients (17%), and pronation-external rotation in 16 patients (28%). Of the 58 patients, 12 (21%) had a unimalleolar fracture, 28 (48%) had a bimalleolar fracture, and 18 (31%) had a trimalleolar fracture. All radiographic indexes measured on the preoperative radiographs, including the medial clear space, tibiofibular overlap, tibiofibular clear space, and fibular position on the lateral view, were significantly different between the injured and intact ankles (Table 2). The medial clear space and tibiofibular clear space of the injured ankle were significantly narrower than those of the intact ankle immediately postoperatively (p < .001). The tibiofibular overlap and fibular position on the lateral view showed no significant differences between the injured and intact ankles immediately postoperatively (Table 3). At the final follow-up examination, the medial clear space and tibiofibular clear space of the injured ankle had become wider compared with those observed on the radiographs obtained immediately
Table 2 Preoperative comparison of radiographic index measurements between injured and intact ankles (N = 58 ankle fractures in 58 patients) Variable
Injured Ankle
Intact Ankle
p Value
Medial clear space (mm) Tibiofibular overlap (mm) Tibiofibular clear space (mm) Fibular position on lateral radiograph
7.9 ± 3.8 4.8 ± 3.3 5.5 ± 2.3 0.64 ± 0.18
3.6 ± 1.0 7.9 ± 2.6 4.2 ± 0.9 0.56 ± 0.08
<.001 <.001 <.001 .026
Data presented as mean ± standard deviation.
Table 3 Comparison of radiographic index measurements between injured and intact ankles immediately postoperatively (N = 58 ankle fractures in 58 patients) Variable
Injured Ankle
Intact Ankle
p Value
Medial clear space (mm) Tibiofibular overlap (mm) Tibiofibular clear space (mm) Fibular position on lateral radiograph
3.2 ± 0.7 7.7 ± 2.8 3.3 ± 1.5 0.58 ± 0.08
3.6 ± 1.0 7.9 ± 2.6 4.2 ± 0.9 0.56 ± 0.08
<.001 .568 <.001 .160
Data presented as mean ± standard deviation.
3
Table 4 Comparison of radiographic index measurements between injured and intact ankles at final follow-up point (14.4 months postoperatively) (N = 58 ankle fractures in 58 patients) Variable
Injured Ankle
Intact Ankle
p Value
Medial clear space (mm) Tibiofibular overlap (mm) Tibiofibular clear space (mm) Fibular position on lateral radiograph
3.8 ± 0.9 6.6 ± 3.1 4.8 ± 1.6 0.57 ± 0.06
3.6 ± 1.0 7.9 ± 2.6 4.2 ± 0.9 0.56 ± 0.08
.522 .003 .013 .347
Data presented as mean ± standard deviation.
postoperatively. The medial clear space and fibular position on the lateral view showed no significant differences between the injured and intact ankles (Table 4). Discussion We evaluated the radiographic outcomes of syndesmosis injuries concurrent with ankle fractures treated with a partially threaded 5.0mm cannulated screw. Mild overcompression was observed immediately postoperatively; however, the ankle mortise had recovered its width by the final follow-up examination (Fig. 2). The present study had some limitations. First, the data were collected retrospectively, introducing the possibility that a strictly uniform protocol might not have been maintained. Second, the follow-up period was relatively short, and longer term follow-up is required. Finally, the present study evaluated the radiographic outcomes alone. Evaluation of both clinical and radiographic outcomes would be more clinically meaningful. However, we believe the results gained from evaluating the radiographic outcomes alone are meaningful because the present study is, to the best of our knowledge, the first report of this fixation technique for syndesmosis injury. The syndesmosis consists of the anterior inferior tibiofibular, interosseous, posterior inferior tibiofibular, and inferior transverse ligaments. Disruption of this complex can lead to diastasis of the fibula from the tibia, which results in a lateral shift of the talus. A lateral shift of the talus as little as 1 mm reduces the contact area of the tibiotalar joint by 42%, which can result in an abnormal pressure distribution and, ultimately, arthritis (14). Therefore, anatomic reduction and effective fixation of the syndesmosis is the most important aspect of syndesmotic fixation. In a survey of orthopedic trauma and foot and ankle fellowship directors and members of the Orthopaedic Trauma Association and the American Orthopaedic Foot and Ankle Society, the most common method for syndesmosis treatment was the use of one or two 3.5mm cortical screws engaging 4 cortices, with removal at 3 months (10). However, screw breakage can occur (11), and screw removal can increase the costs and risks associated with an additional surgery, including infection. In contrast, a partially threaded 5.0-mm cannulated screw does not need to be removed. The partial threads of the screw cause mild overcompression immediately postoperatively. However, the smooth shank with normal fibula motion will loosen the lateral tibial cortex and has no deleterious effect on ankle motion. According to our medical record review, the patients did not complain of ankle stiffness or restriction of activity. In addition, measurement of the radiographic indexes showed that the ankle mortise recovered its width as time progressed (Fig. 3). In general, larger screws are more likely to break than to loosen; however, the smooth shank loosened the screw. No screw breakage occurred in the present study. Screw breakage can result in patient dissatisfaction; thus, reducing the incidence of this complication is highly relevant. Even if screw breakage occurs, the engagement of the screw in 4 cortices would facilitate its removal from
ARTICLE IN PRESS 4
S.Y. Lee et al. / The Journal of Foot & Ankle Surgery ■■ (2017) ■■–■■
Fig. 2. A case of ankle fracture with syndesmosis injury in a 23-year-old male patient. (A) Anteroposterior ankle radiograph showing widened medial clear space (black arrowhead) of the injured ankle compared with the intact ankle. (B) Widened medial clear space (black arrowhead) and tibiofibular clear space (black arrow) are more prominent on the mortise view. (C) The lateral view shows the fibular fracture and concomitant posterior malleolar fracture. (D) Mild overcompression (black arrow) of syndesmosis is observed on the immediate postoperative radiographs. (E) The ankle mortise recovered its width by 1 year postoperatively, as demonstrated by the slightly widened tibiofibular clear space (black arrow). Loosening around the smooth shank (black arrowheads) of the partially threaded screw was considered to have resulted from motion between the tibia and fibula.
the threaded portion. In addition, no infection or repeat fracture was reported as a surgical complication in our cohort. Recently, several studies have reported favorable results with TightRope (Arthrex) fixation. TightRope (Arthrex) has potential advantages over syndesmotic screws, including no hardware removal, no osteolysis, a shorter time to weightbearing, shorter rehabilitation, and improved anatomic motion of the ankle joint (15–17). The less rigid fixation with the TightRope system (Arthrex) stabilizes the syndesmosis, which allows for physiologic motion at the syndesmosis. In addition, Westermann et al (18) reported that the suture button’s dynamic syndesmotic fixation can mitigate clamp-induced malreduction. In contrast, DeCoster (19) argued that the suture button’s dynamic syndesmotic fixation could also lead to the displacement of a well-reduced syndesmosis. However, the large size, 4-cortex engagement, and mild overcompression with the use of a partially threaded 5.0-mm
cannulated screw provides more rigid fixation that maintains the anatomic reduction of the syndesmosis that is crucial in the treatment of syndesmosis injuries. Tornetta et al (9) reported that, in a cadaveric study, ankle dorsiflexion was not limited in 19 ankles despite maximum syndesmotic overcompression with a 4.5-mm lag screw with the ankle in plantarflexion. This suggests that when the syndesmosis was anatomically reduced, overtightening of the ankle joint was not possible, and mild overcompression at the syndesmosis did not have a serious effect on ankle motion. In conclusion, a 5.0-mm partially threaded cannulated screw effectively restored and maintained the normal relationship between the tibia and fibula within the ankle mortise, with little risk of screw breakage or restriction of ankle motion. This appears to be an effective alternative technique for treating syndesmosis injuries concurrent with ankle fractures.
ARTICLE IN PRESS S.Y. Lee et al. / The Journal of Foot & Ankle Surgery ■■ (2017) ■■–■■
5
Fig. 3. Graphs showing the chronologic pattern of the radiographic index measurements of the injured ankles compared with the intact ankles. Radiographic measurements was performed preoperatively (preOp), immediate postoperatively (ImmPo), and at the final follow-up examination (Final). (A) The medial clear space of the injured ankles was significantly wider than that of the intact ankles preoperatively and had become narrower than that immediately postoperatively, and had been restored to a width similar to the intact ankle at the final follow-up point. The (B) tibiofibular overlap, (C) tibiofibular clear space, and (D) fibular position on the lateral view showed a similar tendency.
References 1. Jones MH, Amendola A. Syndesmosis sprains of the ankle: a systematic review. Clin Orthop Relat Res 455:173–175, 2007. 2. Grass R, Rammelt S, Biewener A, Zwipp H. Peroneus longus ligamentoplasty for chronic instability of the distal tibiofibular syndesmosis. Foot Ankle Int 24:392–397, 2003. 3. Harper MC. Delayed reduction and stabilization of the tibiofibular syndesmosis. Foot Ankle Int 22:15–18, 2001. 4. Morris MW, Rice P, Schneider TE. Distal tibiofibular syndesmosis reconstruction using a free hamstring autograft. Foot Ankle Int 30:506–511, 2009. 5. van den Bekerom MP. Diagnosing syndesmotic instability in ankle fractures. World J Orthop 2:51–56, 2011. 6. van den Bekerom MP, de Leeuw PA, van Dijk CN. Delayed operative treatment of syndesmotic instability: current concepts review. Injury 40:1137–1142, 2009. 7. Beumer A, Campo MM, Niesing R, Day J, Kleinrensink GJ, Swierstra BA. Screw fixation of the syndesmosis: a cadaver model comparing stainless steel and titanium screws and three and four cortical fixation. Injury 36:60–64, 2005. 8. Hoiness P, Stromsoe K. Tricortical versus quadricortical syndesmosis fixation in ankle fractures: a prospective, randomized study comparing two methods of syndesmosis fixation. J Orthop Trauma 18:331–337, 2004. 9. Tornetta P III, Spoo JE, Reynolds FA, Lee C. Overtightening of the ankle syndesmosis: is it really possible? J Bone Joint Surg Am 83A:489–492, 2001.
10. Bava E, Charlton T, Thordarson D. Ankle fracture syndesmosis fixation and management: the current practice of orthopedic surgeons. Am J Orthop (Belle Mead NJ) 39:242–246, 2010. 11. Bell DP, Wong MK. Syndesmotic screw fixation in Weber C ankle injuries—should the screw be removed before weight bearing? Injury 37:891–898, 2006. 12. Choi Y, Kwon SS, Chung CY, Park MS, Lee SY, Lee KM. Preoperative radiographic and CT findings predicting syndesmotic injuries in supination-external rotation-type ankle fractures. J Bone Joint Surg Am 96:1161–1167, 2014. 13. Stoffel K, Wysocki D, Baddour E, Nicholls R, Yates P. Comparison of two intraoperative assessment methods for injuries to the ankle syndesmosis: a cadaveric study. J Bone Joint Surg Am 91:2646–2652, 2009. 14. Ramsey PL, Hamilton W. Changes in tibiotalar area of contact caused by lateral talar shift. J Bone Joint Surg Am 58:356–357, 1976. 15. Espinosa N, Smerek JP, Myerson MS. Acute and chronic syndesmosis injuries: pathomechanisms, diagnosis and management. Foot Ankle Clin 11:639–657, 2006. 16. Fites B, Kunes J, Madaleno J, Silvestri P, Johnson DL. Latent syndesmosis injuries in athletes. Orthopedics 29:124–127, 2006. 17. Qamar F, Kadakia A, Venkateswaran B. An anatomical way of treating ankle syndesmotic injuries. J Foot Ankle Surg 50:762–765, 2011. 18. Westermann RW, Rungprai C, Goetz JE, Femino J, Amendola A, Phisitkul P. The effect of suture-button fixation on simulated syndesmotic malreduction: a cadaveric study. J Bone Joint Surg Am 96:1732–1738, 2014. 19. DeCoster TA. Is “loose” fixation of the syndesmosis really better? Commentary on an article by Robert W. Westermann, MD, et al.: “the effect of suture-button fixation on simulated syndesmotic malreduction: a cadaveric study”. J Bone Joint Surg Am 96:e179, 2014.
Contents lists available at ScienceDirect
The Journal of Foot & Ankle Surgery j o u r n a l h o m e p a g e : w w w. j f a s . o r g
Original Research
Syndesmosis Fixation in Unstable Ankle Fractures Using a Partially Threaded 5.0-mm Cannulated Screw Seung Yeol Lee, MD 1, Sang Young Moon, MD 2, Moon Seok Park, MD 3, Byung Chae Jo, MD 4, Hyunseok Jeong, MD 5, Kyoung Min Lee, MD 6 1Clinical
Associate Professor, Department of Orthopaedic Surgery, Ewha Womans University Mokdong Hospital, Seoul, Republic of Korea Seocho Gangnam Yeok Orthopedic Clinic, Seoul, Republic of Korea Professor, Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Republic of Korea 4 Orthopedist, Department of Orthopaedic Surgery, Seoul Jaeil Hospital, Kyungki, Republic of Korea 5Orthopedist, Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Republic of Korea 6 Clinical Associate Professor, Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Kyungki, Republic of Korea 2Orthopedist, 3Clinical
A R T I C L E
I N F O
Level of Clinical Evidence: 4
Keywords: cannulated screw mortise syndesmosis injury
A B S T R A C T
The present study evaluated the radiographic outcomes of syndesmosis injuries treated with a partially threaded 5.0-mm cannulated screw. The present study included 58 consecutive patients with syndesmosis injuries concurrent with ankle fractures who had undergone operative fixation with a partially threaded 5.0-mm cannulated screw to repair the syndesmosis injury. Radiographic indexes, including the medial clear space, tibiofibular overlap, tibiofibular clear space, and fibular position on the lateral radiograph, were measured on the preoperative, immediate postoperative, and final follow-up radiographs. The measurements were compared between the injured and intact ankles. All preoperative radiographic indexes, including the medial clear space (p < .001), tibiofibular overlap (p < .001), tibiofibular clear space (p < .001), and fibular position on the lateral radiograph (p = .026), were significantly different between the injured and intact ankles. The medial clear space of the injured ankle was significantly wider than that of the intact ankle preoperatively (p < .001) and had become significantly narrower immediately postoperatively (p < .001). Finally, the medial clear space was not significantly different between the injured and intact ankles at the final follow-up examination (p = .522). No screw breakage or repeat fractures were observed. A 5.0-mm partially threaded cannulated screw effectively restored and maintained the normal relationship between the tibia and fibula within the ankle mortise with a low risk of complications. This appears to be an effective alternative technique to treat syndesmosis injuries concurrent with ankle fractures. © 2018 by the American College of Foot and Ankle Surgeons. All rights reserved.
Syndesmosis injuries are relatively common with athletic activity, accounting for ≤18% of all ankle sprains (1). They often occur concurrently with ankle fractures and aggravate the instability of the fracture. The key to treating this type of injury is anatomic reduction and effective stabilization of the ankle mortise, which permits the healing of the syndesmotic ligaments. When uncorrected, chronic syndesmotic instability can result in pain during walking, the ankle “giving way,” and, possibly, early degenerative arthritis (2–6). Financial Disclosure: This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) (NRF-2017R1D1A1B03033913) and the Ministry of Agriculture, Food and Rural Affairs (MAFRA) (117051-3). Conflict of Interest: None reported. Address correspondence to: Kyoung Min Lee, MD, Department of Orthopedic Surgery, Seoul National University Bundang Hospital, 300 Gumi-Dong, Bundang-Gu, Sungnam, Kyungki 463-707, Republic of Korea. E-mail address: [email protected] (K.M. Lee).
Several fixation devices have been used to hold the syndesmosis in position, including syndesmotic screws, bioabsorbable screws, Kirschner wires, and the TightRope system (Arthrex, Naples, FL). Of these, syndesmotic screw fixation is the current standard treatment (7–9). However, no general consensus has been reached regarding the technical aspects of syndesmotic screw fixation. The screw type, screw size, number of cortices engaged, the use of 1 or 2 screws, the position of the ankle during screw fixation, the time required before allowing weightbearing, and the time to screw removal have all been debated. A survey of orthopedic trauma and foot and ankle fellowship directors and members of the Orthopaedic Trauma Association and the American Orthopaedic Foot and Ankle Society found that the most common method for treating syndesmosis injuries involved using one or two 3.5-mm cortical screws engaging 4 cortices, which are removed at 3 months postoperatively (10). However, screw breakage occasionally
1067-2516/$ - see front matter © 2018 by the American College of Foot and Ankle Surgeons. All rights reserved. https://doi.org/10.1053/j.jfas.2017.12.012
ARTICLE IN PRESS 2
S.Y. Lee et al. / The Journal of Foot & Ankle Surgery ■■ (2017) ■■–■■
Fig. 1. Radiographic indexes measured on (A) anteroposterior and (B) lateral view. Medial clear space (a) is the distance between the articular surface of the medial malleolus and the medial talar articular surface. Tibiofibular overlap (b) is the overlap of the lateral malleolus and the anterior tibial tubercle, measured where the overlap is the largest. The tibiofibular clear space (c) is the distance between the medial border of the fibula and the lateral border of the posterior tibia as it extends into the incisura fibularis, measured 1 cm proximal to the plafond. Fibular position on the lateral view (d/e) is the relative position of the fibular center (d) on a length (e) between the anterior and posterior margins of the tibial plafond.
occurs, necessitating removal of the syndesmotic screw before weightbearing (11). Therefore, we modified the syndesmotic screw fixation technique to minimize the risks of breakage. The aim of the present study was to evaluate the radiographic outcomes of syndesmosis injuries treated with a partially threaded 5.0-mm cannulated screw. We hypothesized that the screw could effectively restore and maintain the normal relationship between the tibia and fibula within the ankle mortise.
through the plate hole across the syndesmosis, engaging 4 cortices, 1 to 1.5 cm above the tibia plafond with the ankle in 5° of dorsiflexion. The guide pin facilitated the placement of the screw in the correct position. The deltoid ligament was left unrepaired. Postoperatively, the patients were placed in a well-padded short-leg cast with the ankle in neutral dorsiflexion and instructed to maintain non-weightbearing status for the first 6 weeks. The patients were then placed in a removable short-leg splint, and ankle movement throughout the entire range of motion was encouraged from 2 weeks postoperatively onward. Tolerable and progressive weightbearing was allowed from 6 weeks postoperatively, and then patients were allowed to walk without any limitations.
Patients and Methods
Ankle radiographs of the anteroposterior, mortise, and lateral views were obtained using a UT 2000 x-ray machine (Philips Research, Eindhoven, The Netherlands) at a source-to-image distance of ~100 cm with the patient in the supine position. The radiograph setting depended on the patient’s body size, with a range of 46 to 50 kVp and 4.5 to 5 mA. Radiographic images were retrieved using a picture archiving and communication system, and measurements were subsequently performed using picture archiving and communication system software (IMPAX; Agfa Healthcare, Mortsel, Belgium). Radiographic indexes, including the medial clear space, tibiofibular overlap, tibiofibular clear space, and fibular position on the lateral view (Fig. 1), were measured on the preoperative, immediate postoperative, and final follow-up radiographs for the injured ankle. Those indexes were also measured once for the intact ankle.
The institutional review board of our institute approved the present study. Consecutive patients who had undergone operative treatment with a partially threaded 5.0-mm cannulated screw for syndesmosis injuries concurrent with ankle fractures from May 2009 to December 2013 were enrolled in the present study. All the patients underwent preoperative ankle radiographs, including anteroposterior, lateral, and mortise views. The demographic data, including age, sex, height, and weight, were recorded. The exclusion criteria were as follows: (1) ankle fractures from a direct blow; and (2) abnormal ankle anatomy from a congenital anomaly, previous surgery, trauma, infection, or tumor.
Radiographic Examinations and Measurements
Operative Technique and Postoperative Management
Statistical Analysis
All operations were performed by 2 of us (M.S.P., K.M.L.) with the same treatment policy. The patients underwent operative reduction and internal fixation using a onethird tubular plate and screws for the lateral malleolus and one or two 5.0-mm cannulated screws or tension band wiring for the medial malleolus. The posterior malleolus was fixed using a 5.0-mm cannulated screw if surgical fixation was indicated. Unstable syndesmosis injuries were evaluated using a lateral stress test intraoperatively (12) after all fractures had been internally fixed. Unstable injuries were defined as those with a ≥5 mm tibiofibular clear space on the fluoroscopic lateral stress test (5,13). The syndesmosis was held in place with a large reduction clamp to compress the tibia and fibula. To avoid oblique malreduction, the clamp tips were placed on the lateral malleolar ridge of the fibula, which is the insertion of the peroneal retinaculum, and the center of the anteroposterior width of the medial tibial cortex 10 mm above the ankle joint line. Next, a partially threaded 5.0-mm cannulated screw was placed
Descriptive statistics, including the mean, standard deviation, and proportion, were calculated. A Kolmogorov-Smirnov test was used to verify the normality of the distribution of the continuous variables. Comparisons between the injured and intact ankles were conducted using a t test, paired t test, or Mann-Whitney U test according to the data characteristics. Statistical analyses were conducted using SPSS, version 20.0 (IBM, Armonk, NY) and R, version 2.15.1 (R Foundation, Vienna, Austria). p Values < .05 were considered statistically significant.
Results A total of 58 patients were included in the present study. The mean age of the patients at surgery was 39.9 ± 14.4 years. Of the 58 patients,
ARTICLE IN PRESS S.Y. Lee et al. / The Journal of Foot & Ankle Surgery ■■ (2017) ■■–■■
Table 1 Data summary Variable
Value
Patients Age (y) Sex Male Female Height (cm) Weight (kg) BMI (kg/m2) Follow-up duration (mo) Lauge-Hansen classification SA PER PA PER Fracture extent Unimalleolar Bimalleolar Trimalleolar
58 39.9 ± 14.4 45 13 169.6 ± 8.1 72.2 ± 11.5 25.0 ± 2.8 14.4 ± 5.1 0 32 10 16 12 28 18
Data presented as mean ± standard deviation or n. Abbreviations: BMI, body mass index; PA, pronation-abduction; PER, pronationexternal rotation; SA, supination-adduction; SER, supination-external rotation.
45 were male (78%) and 13 were female (22%; Table 1). The LaugeHansen classification was as follows: supination-external rotation in 32 patients (55%), pronation-abduction in 10 patients (17%), and pronation-external rotation in 16 patients (28%). Of the 58 patients, 12 (21%) had a unimalleolar fracture, 28 (48%) had a bimalleolar fracture, and 18 (31%) had a trimalleolar fracture. All radiographic indexes measured on the preoperative radiographs, including the medial clear space, tibiofibular overlap, tibiofibular clear space, and fibular position on the lateral view, were significantly different between the injured and intact ankles (Table 2). The medial clear space and tibiofibular clear space of the injured ankle were significantly narrower than those of the intact ankle immediately postoperatively (p < .001). The tibiofibular overlap and fibular position on the lateral view showed no significant differences between the injured and intact ankles immediately postoperatively (Table 3). At the final follow-up examination, the medial clear space and tibiofibular clear space of the injured ankle had become wider compared with those observed on the radiographs obtained immediately
Table 2 Preoperative comparison of radiographic index measurements between injured and intact ankles (N = 58 ankle fractures in 58 patients) Variable
Injured Ankle
Intact Ankle
p Value
Medial clear space (mm) Tibiofibular overlap (mm) Tibiofibular clear space (mm) Fibular position on lateral radiograph
7.9 ± 3.8 4.8 ± 3.3 5.5 ± 2.3 0.64 ± 0.18
3.6 ± 1.0 7.9 ± 2.6 4.2 ± 0.9 0.56 ± 0.08
<.001 <.001 <.001 .026
Data presented as mean ± standard deviation.
Table 3 Comparison of radiographic index measurements between injured and intact ankles immediately postoperatively (N = 58 ankle fractures in 58 patients) Variable
Injured Ankle
Intact Ankle
p Value
Medial clear space (mm) Tibiofibular overlap (mm) Tibiofibular clear space (mm) Fibular position on lateral radiograph
3.2 ± 0.7 7.7 ± 2.8 3.3 ± 1.5 0.58 ± 0.08
3.6 ± 1.0 7.9 ± 2.6 4.2 ± 0.9 0.56 ± 0.08
<.001 .568 <.001 .160
Data presented as mean ± standard deviation.
3
Table 4 Comparison of radiographic index measurements between injured and intact ankles at final follow-up point (14.4 months postoperatively) (N = 58 ankle fractures in 58 patients) Variable
Injured Ankle
Intact Ankle
p Value
Medial clear space (mm) Tibiofibular overlap (mm) Tibiofibular clear space (mm) Fibular position on lateral radiograph
3.8 ± 0.9 6.6 ± 3.1 4.8 ± 1.6 0.57 ± 0.06
3.6 ± 1.0 7.9 ± 2.6 4.2 ± 0.9 0.56 ± 0.08
.522 .003 .013 .347
Data presented as mean ± standard deviation.
postoperatively. The medial clear space and fibular position on the lateral view showed no significant differences between the injured and intact ankles (Table 4). Discussion We evaluated the radiographic outcomes of syndesmosis injuries concurrent with ankle fractures treated with a partially threaded 5.0mm cannulated screw. Mild overcompression was observed immediately postoperatively; however, the ankle mortise had recovered its width by the final follow-up examination (Fig. 2). The present study had some limitations. First, the data were collected retrospectively, introducing the possibility that a strictly uniform protocol might not have been maintained. Second, the follow-up period was relatively short, and longer term follow-up is required. Finally, the present study evaluated the radiographic outcomes alone. Evaluation of both clinical and radiographic outcomes would be more clinically meaningful. However, we believe the results gained from evaluating the radiographic outcomes alone are meaningful because the present study is, to the best of our knowledge, the first report of this fixation technique for syndesmosis injury. The syndesmosis consists of the anterior inferior tibiofibular, interosseous, posterior inferior tibiofibular, and inferior transverse ligaments. Disruption of this complex can lead to diastasis of the fibula from the tibia, which results in a lateral shift of the talus. A lateral shift of the talus as little as 1 mm reduces the contact area of the tibiotalar joint by 42%, which can result in an abnormal pressure distribution and, ultimately, arthritis (14). Therefore, anatomic reduction and effective fixation of the syndesmosis is the most important aspect of syndesmotic fixation. In a survey of orthopedic trauma and foot and ankle fellowship directors and members of the Orthopaedic Trauma Association and the American Orthopaedic Foot and Ankle Society, the most common method for syndesmosis treatment was the use of one or two 3.5mm cortical screws engaging 4 cortices, with removal at 3 months (10). However, screw breakage can occur (11), and screw removal can increase the costs and risks associated with an additional surgery, including infection. In contrast, a partially threaded 5.0-mm cannulated screw does not need to be removed. The partial threads of the screw cause mild overcompression immediately postoperatively. However, the smooth shank with normal fibula motion will loosen the lateral tibial cortex and has no deleterious effect on ankle motion. According to our medical record review, the patients did not complain of ankle stiffness or restriction of activity. In addition, measurement of the radiographic indexes showed that the ankle mortise recovered its width as time progressed (Fig. 3). In general, larger screws are more likely to break than to loosen; however, the smooth shank loosened the screw. No screw breakage occurred in the present study. Screw breakage can result in patient dissatisfaction; thus, reducing the incidence of this complication is highly relevant. Even if screw breakage occurs, the engagement of the screw in 4 cortices would facilitate its removal from
ARTICLE IN PRESS 4
S.Y. Lee et al. / The Journal of Foot & Ankle Surgery ■■ (2017) ■■–■■
Fig. 2. A case of ankle fracture with syndesmosis injury in a 23-year-old male patient. (A) Anteroposterior ankle radiograph showing widened medial clear space (black arrowhead) of the injured ankle compared with the intact ankle. (B) Widened medial clear space (black arrowhead) and tibiofibular clear space (black arrow) are more prominent on the mortise view. (C) The lateral view shows the fibular fracture and concomitant posterior malleolar fracture. (D) Mild overcompression (black arrow) of syndesmosis is observed on the immediate postoperative radiographs. (E) The ankle mortise recovered its width by 1 year postoperatively, as demonstrated by the slightly widened tibiofibular clear space (black arrow). Loosening around the smooth shank (black arrowheads) of the partially threaded screw was considered to have resulted from motion between the tibia and fibula.
the threaded portion. In addition, no infection or repeat fracture was reported as a surgical complication in our cohort. Recently, several studies have reported favorable results with TightRope (Arthrex) fixation. TightRope (Arthrex) has potential advantages over syndesmotic screws, including no hardware removal, no osteolysis, a shorter time to weightbearing, shorter rehabilitation, and improved anatomic motion of the ankle joint (15–17). The less rigid fixation with the TightRope system (Arthrex) stabilizes the syndesmosis, which allows for physiologic motion at the syndesmosis. In addition, Westermann et al (18) reported that the suture button’s dynamic syndesmotic fixation can mitigate clamp-induced malreduction. In contrast, DeCoster (19) argued that the suture button’s dynamic syndesmotic fixation could also lead to the displacement of a well-reduced syndesmosis. However, the large size, 4-cortex engagement, and mild overcompression with the use of a partially threaded 5.0-mm
cannulated screw provides more rigid fixation that maintains the anatomic reduction of the syndesmosis that is crucial in the treatment of syndesmosis injuries. Tornetta et al (9) reported that, in a cadaveric study, ankle dorsiflexion was not limited in 19 ankles despite maximum syndesmotic overcompression with a 4.5-mm lag screw with the ankle in plantarflexion. This suggests that when the syndesmosis was anatomically reduced, overtightening of the ankle joint was not possible, and mild overcompression at the syndesmosis did not have a serious effect on ankle motion. In conclusion, a 5.0-mm partially threaded cannulated screw effectively restored and maintained the normal relationship between the tibia and fibula within the ankle mortise, with little risk of screw breakage or restriction of ankle motion. This appears to be an effective alternative technique for treating syndesmosis injuries concurrent with ankle fractures.
ARTICLE IN PRESS S.Y. Lee et al. / The Journal of Foot & Ankle Surgery ■■ (2017) ■■–■■
5
Fig. 3. Graphs showing the chronologic pattern of the radiographic index measurements of the injured ankles compared with the intact ankles. Radiographic measurements was performed preoperatively (preOp), immediate postoperatively (ImmPo), and at the final follow-up examination (Final). (A) The medial clear space of the injured ankles was significantly wider than that of the intact ankles preoperatively and had become narrower than that immediately postoperatively, and had been restored to a width similar to the intact ankle at the final follow-up point. The (B) tibiofibular overlap, (C) tibiofibular clear space, and (D) fibular position on the lateral view showed a similar tendency.
References 1. Jones MH, Amendola A. Syndesmosis sprains of the ankle: a systematic review. Clin Orthop Relat Res 455:173–175, 2007. 2. Grass R, Rammelt S, Biewener A, Zwipp H. Peroneus longus ligamentoplasty for chronic instability of the distal tibiofibular syndesmosis. Foot Ankle Int 24:392–397, 2003. 3. Harper MC. Delayed reduction and stabilization of the tibiofibular syndesmosis. Foot Ankle Int 22:15–18, 2001. 4. Morris MW, Rice P, Schneider TE. Distal tibiofibular syndesmosis reconstruction using a free hamstring autograft. Foot Ankle Int 30:506–511, 2009. 5. van den Bekerom MP. Diagnosing syndesmotic instability in ankle fractures. World J Orthop 2:51–56, 2011. 6. van den Bekerom MP, de Leeuw PA, van Dijk CN. Delayed operative treatment of syndesmotic instability: current concepts review. Injury 40:1137–1142, 2009. 7. Beumer A, Campo MM, Niesing R, Day J, Kleinrensink GJ, Swierstra BA. Screw fixation of the syndesmosis: a cadaver model comparing stainless steel and titanium screws and three and four cortical fixation. Injury 36:60–64, 2005. 8. Hoiness P, Stromsoe K. Tricortical versus quadricortical syndesmosis fixation in ankle fractures: a prospective, randomized study comparing two methods of syndesmosis fixation. J Orthop Trauma 18:331–337, 2004. 9. Tornetta P III, Spoo JE, Reynolds FA, Lee C. Overtightening of the ankle syndesmosis: is it really possible? J Bone Joint Surg Am 83A:489–492, 2001.
10. Bava E, Charlton T, Thordarson D. Ankle fracture syndesmosis fixation and management: the current practice of orthopedic surgeons. Am J Orthop (Belle Mead NJ) 39:242–246, 2010. 11. Bell DP, Wong MK. Syndesmotic screw fixation in Weber C ankle injuries—should the screw be removed before weight bearing? Injury 37:891–898, 2006. 12. Choi Y, Kwon SS, Chung CY, Park MS, Lee SY, Lee KM. Preoperative radiographic and CT findings predicting syndesmotic injuries in supination-external rotation-type ankle fractures. J Bone Joint Surg Am 96:1161–1167, 2014. 13. Stoffel K, Wysocki D, Baddour E, Nicholls R, Yates P. Comparison of two intraoperative assessment methods for injuries to the ankle syndesmosis: a cadaveric study. J Bone Joint Surg Am 91:2646–2652, 2009. 14. Ramsey PL, Hamilton W. Changes in tibiotalar area of contact caused by lateral talar shift. J Bone Joint Surg Am 58:356–357, 1976. 15. Espinosa N, Smerek JP, Myerson MS. Acute and chronic syndesmosis injuries: pathomechanisms, diagnosis and management. Foot Ankle Clin 11:639–657, 2006. 16. Fites B, Kunes J, Madaleno J, Silvestri P, Johnson DL. Latent syndesmosis injuries in athletes. Orthopedics 29:124–127, 2006. 17. Qamar F, Kadakia A, Venkateswaran B. An anatomical way of treating ankle syndesmotic injuries. J Foot Ankle Surg 50:762–765, 2011. 18. Westermann RW, Rungprai C, Goetz JE, Femino J, Amendola A, Phisitkul P. The effect of suture-button fixation on simulated syndesmotic malreduction: a cadaveric study. J Bone Joint Surg Am 96:1732–1738, 2014. 19. DeCoster TA. Is “loose” fixation of the syndesmosis really better? Commentary on an article by Robert W. Westermann, MD, et al.: “the effect of suture-button fixation on simulated syndesmotic malreduction: a cadaveric study”. J Bone Joint Surg Am 96:e179, 2014.