Technique tip: a revised method of the Cotton test for intra-operative evaluation of syndesmotic injuries

The use of intraoperative comparative fluoroscopy allows for assessing sagittal reduction and predicting syndesmosis reduction in ankle fractures

Intraoperative fluoroscopic parameters have shown to be poor predictors for ankle syndesmosis reduction, with up to 52% of syndesmotic malreduction (SMR) reported in the literature. Anteroposterior Tibio-Fibular index (APTF) was previously described to evaluate sagittal tibiofibular alignment in lateral ankle radiographs with a high correlation between both ankles in uninjured subjects. Reproducible intraoperative measurements for sagittal syndesmotic reduction are lacking. We propose the use of the "cAPTF," calculated as the absolute difference between the APTF of the non-injured and the operated ankle, to evaluate sagittal syndesmotic reduction.

OBJECTIVE

Determine the predictive capability of cAPTF for SMR.

METHOD

Prospective observational study.

INCLUSION CRITERIA

patients with unstable ankle fractures requiring syndesmotic fixation, with a healthy contralateral ankle. Intraoperatively APTF was measured in both ankles after syndesmotic fixation. Postoperatively cAPTF was calculated. Only direct syndesmosis visualization through the lateral approach and AP and mortise views were used by surgeons to assess syndesmotic reduction. Quality of syndesmotic reduction was evaluated with bilateral postoperative CT. To estimate cAPTF discriminatory power for SMR, a receiver operative characteristic (ROC) curve was obtained and the area under the ROC curve was calculated. Youden index was used to determine the ideal cAPTF cut-off value for predicting SMR. For this determined cut-off value, sensitivity, specificity, and likelihood ratio were calculated.

RESULTS

Fifty-two patients were included. Sixteen (30%) had SMR. Patients with SMR had a statistically significant higher cAPTF value than the well reduced (median 0.26 vs 0.09; P < 0.01). The cAPTF cut-off value to predict SMR was 0.161. A cAPTF greater than 0.161 had 100% sensitivity and 97,2% specificity for SMR. The area under the ROC curve was 0.99.

CONCLUSION

Intraoperative cAPTF has excellent discriminatory power for predicting syndesmotic malreduction. We propose the routine use of intraoperative bilateral comparative fluoroscopy to assess sagittal syndesmotic reduction.

Evidence-Based Surgical Treatment Algorithm for Unstable Syndesmotic Injuries

Background: Surgical treatment of unstable syndesmotic injuries is not trivial, and there are no generally accepted treatment guidelines. The most common controversies regarding surgical treatment are related to screw fixation versus dynamic fixation, the use of reduction clamps, open versus closed reduction, and the role of the posterior malleolus and of the anterior inferior tibiofibular ligament (AITFL). Our aim was to draw important conclusions from the pertinent literature concerning surgical treatment of unstable syndesmotic injuries, to transform these conclusions into surgical principles supported by the literature, and finally to fuse these principles into an evidence-based surgical treatment algorithm. Methods: PubMed, Embase, Google Scholar, The Cochrane Database of Systematic Reviews, and the reference lists of systematic reviews of relevant studies dealing with the surgical treatment of unstable syndesmotic injuries were searched independently by two reviewers using specific terms and limits. Surgical principles supported by the literature were fused into an evidence-based surgical treatment algorithm. Results: A total of 171 articles were included for further considerations. Among them, 47 articles concerned syndesmotic screw fixation and 41 flexible dynamic fixations of the syndesmosis. Twenty-five studies compared screw fixation with dynamic fixations, and seven out of these comparisons were randomized controlled trials. Nineteen articles addressed the posterior malleolus, 14 the role of the AITFL, and eight the use of reduction clamps. Anatomic reduction is crucial to prevent posttraumatic osteoarthritis. Therefore, flexible dynamic stabilization techniques should be preferred whenever possible. An unstable AITFL should be repaired and augmented, as it represents an important stabilizer of external rotation of the distal fibula. Conclusions: The current literature provides sufficient arguments for the development of an evidence-based surgical treatment algorithm for unstable syndesmotic injuries.

Distal Radioulnar Joint Instability: Assessment of Three Intraoperative Radiographic Stress Tests

Background: The purpose of this study is to describe three radiographic stress tests that could be used to examine for distal radioulnar joint (DRUJ) instability intraoperatively, and to determine their ability to detect DRUJ instability after sequentially sectioning the DRUJ. Methods: Eleven fresh frozen cadaveric upper extremities (mean age 52.6 ± 14.9 years) were obtained. We sequentially sectioned the DRUJ. After each component of the DRUJ was sectioned, we performed three radiographic stress tests-squeeze test, ulnar pull in coronal plane, and simulated DRUJ ballotment test. Results: The squeeze test detected a significant increase in diastasis relative to the intact DRUJ after sectioning of the foveal insertion of the triangular fibrocartilage complex (TFCC; 1.0 mm) and the distal oblique bundle (DOB; 1.2 mm). The ulnar pull test in the coronal plane detected a significant increase in diastasis relative to the intact DRUJ after sectioning of the dorsal and volar radioulnar ligaments (2 mm), the foveal insertion of the TFCC (2.6 mm), and the DOB (4.4 mm). The simulated DRUJ ballotment test detected a significant increase in dorsal translation of the ulna relative to the intact DRUJ with sectioning of the foveal insertion of the TFCC (4.9 mm) and the DOB (5.6 mm). Conclusion: The squeeze test and simulated DRUJ ballotment test detect a significant increase in diastasis after the foveal attachment of the TFCC was sectioned. The ulnar pull test in the coronal plane was the most sensitive test for detecting a significant increase in diastasis relative to the intact DRUJ.

Comparison between cotton test and tap test for the assessment of coronal syndesmotic instability: A cadaveric study

INTRODUCTION

In surgically treated rotational malleolar fractures, residual syndesmotic instability is typically assessed following fixation with the widely used intraoperative Cotton test. However, due to its dynamic nature, there are inconsistencies of the magnitude and direction of the distraction force when attempting to pull the fibula away from the tibia using a bone hook. The novel Tap test advances a cortical tap through a drilled hole in the fibula with a stable, unidirectional distraction force applied to the tibia. The objective of this cadaveric study was to compare the Cotton and Tap tests as diagnostic tools for coronal plane syndesmotic instability.

METHODS

Tibiofibular Clear Space (TFCS) of 10 cadaveric specimens was measured for: intact, non-stressed; intact, stressed; injured, non-stressed; and injured, stressed (Tap and Cotton tests). In injured conditions, the syndesmotic ligamentous complex was sectioned using an anterolateral longitudinal approach. Perfect fluoroscopic Mortise images were acquired for all conditions. Two independent and blinded Orthopaedic Foot and Ankle Surgeons measured TFCS 1 cm proximal to the ankle joint line. Intra and interobserver reliabilities were assessed by Intraclass Correlation Coefficient. Syndesmotic TFCS values for all conditions were compared by paired Wilcoxon. Diagnostic performance of the Cotton and Tap tests was assessed using a relative increase of TFCS > 2 mm when comparing intact stressed and injured stressed conditions. P-values <0.05 were considered significant.

RESULTS

The intraclass correlation coefficient for intraobserver and interobserver reliability was respectively 0.96 and 0.79. TFCS measurements were similar in intact non-stressed, intact stressed (both Cotton and Tap tests) and injured non-stressed conditions, with mean values and 95% Confidence Intervals of: intact non-stressed, 3.5 mm; intact stressed, 3.6 mm (Cotton test) and 4.0 mm (Tap test); injured non-stressed, 3.8 mm. The Cotton test and Tap test had, respectively, 73.3% and 70% sensitivity, 100% and 90% specificity, 86.7% and 80% diagnostic accuracy.

CONCLUSIONS

Our cadaveric study compared the Cotton and Tap tests for detection of coronal plane syndesmotic instability. Both tests demonstrated similar increases in the TFCS measurements in stressed injured conditions when compared to intact non-stressed and stressed conditions, as well as injured non-stressed conditions.

A standardized approach for exact CT-based three-dimensional position analysis in the distal tibiofibular joint

Background

Assessment of tibiofibular reduction presents an intra- and postoperative challenge. Numerous two-dimensional measurement methods have been described, most of them highly dependent on leg orientation and rater. Aim of the present work was to develop a standardized and orientation-independent 3D based method for the assessment of syndesmotic joint position.

Methods

In a retrospective single center study, 3D models of bilateral ankle joints, either after unilateral syndesmosis stabilization (operative group) or with no injury (native group) were superimposed (best fit matching) and aligned uniformly. Based on center of gravity calculations three orientation- and rater-independent parameters were determined: tibiofibular clears space (CS), vertical offset between both fibulae, and translation angle of the fibulae about tibia axis.

Results

Bilateral CT datasets of 57 native and 47 postoperative patients were analyzed. In the native group mean CS was 2.7 (SD, 0.8; range, 0.7–4.9) mm, mean CS side difference was 0.62 (SD, 0.45) mm and mean translation angle was 1.6 (SD, 1.4) degrees regarding absolute values. The operative group was found to show a significantly higher CS side difference of 0.88 (SD, 0.75) mm compared to native group (P = .046). Compared to the healthy contralateral side, operated fibulae showed mean proximal displacement of 0.56 (SD, 1.67) mm (P = .025), dorsal displacement of 1.5 (SD 4.1) degrees (P = .017).

Conclusion

By using 3D best fit matching, orientation- and rater-dependent errors can be minimized. Large interindividual and small intraindividual differences of uninjured couples support previous recommendations for bilateral imaging.

Trial registration: AZ 131/18-ek; AZ 361/19-ek

Level of evidence

Level III.

Fixation of Posterior Malleolar Fractures with Posterior Plating Through a Posterolateral Approach

BACKGROUND

We aimed to evaluate radiologic and clinical outcomes of ankle fractures involving posterior fragments that were fixed with a posterior plate by the posterolateral approach.

METHODS

Sixty-five patients who were followed for at least 12 months and were older than 18 years were included. The posterior malleolus fractures were classified according to the Haraguchi classification system with computed tomography (CT). The posterior malleolus fragments were fixed with a plate through a posterolateral approach. Intra-articular step-off, reduction of the posterior malleolar fragment, and fibular position in the incisura were evaluated by early postoperative CT. American Orthopaedic Foot and Ankle Society (AOFAS) score and visual analog scale pain score were used for clinical assessment.

RESULTS

The posterior malleolus fractures were classified as Haraguchi type 1 in 45 patients (69.2%), Haraguchi type 2 in 12 patients (18.5%), and Haraguchi type 3 in eight patients (12.3%). No patients showed signs of instability or loss of reduction on direct radiographs during follow-up. Postoperative CT showed no loss of reduction in the posterior malleolus and tibiofibular alignment. On evaluation, there was no intra-articular step-off (<1) in any of the patients. The mean AOFAS score was calculated to be 91.6. The mean visual analog scale score was 1.2.

CONCLUSIONS

We conclude that direct posterior fixation with the posterolateral approach can be a good option for ankle fractures involving posterior malleolar fragments.

Comparison of Outcome of Deltoid Ligament Repair According to Location of Suture Anchors in Rotational Ankle Fracture

BACKGROUND

The suture anchors for the repair of deltoid ligament in rotational ankle fracture are inserted mostly into the medial malleolus, but sometimes are placed into the talus depending on the rupture site. This study sought to compare the radiological and clinical outcomes of deltoid ligament repair according to using these 2 locations for suture anchor placement.

METHODS

The cases of 131 patients (114 patients with suture anchors on the medial malleolus and 17 patients with suture anchors on the talus) who underwent deltoid ligament repair along with ankle fracture fixation were retrospectively reviewed. Medial clear space oblique (MCSo), medial clear space perpendicular (MCSp), tibiofibular clear space (TFCS), and tibiofibular overlap (TFO) were measured as radiological outcomes, while the Olerud-Molander Ankle Score (OMAS) and visual analog scale (VAS) score for pain were calculated as clinical outcomes. The follow-up period did not differ between the 2 groups (16.8 ± 10.9 months in the medial malleolus group vs 17.9 ± 14.3 months in the talus group; P = .670).

RESULTS

There were no differences in MCSo, MCSp, TFCS, and TFO at 3 months after surgery and final follow-up. The OMAS and VAS for pain did not show intergroup differences at final follow-up.

CONCLUSION

The surgical outcome of deltoid ligament repair in rotational ankle fracture did not differ whether the suture anchors were inserted into the medial malleolus or into the talus.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Physical Examination of the Ankle: A Review of the Original Orthopedic Special Test Description and Scientific Validity of Common Tests for Ankle Examination

OBJECTIVES

To review the literature, identify and describe commonly used special tests for diagnosing injury to the ligaments of the ankle complex, present the distinguishing characteristics and limitations of each test, and discuss the current evidence for the clinical use of each test.

DATA SOURCES

Multiple PubMed (1920-2018) and CINAHL (1920-2018) searches were conducted and various musculoskeletal examination textbooks were reviewed to examine common orthopedic tests used to assess the ankle. The articles were reviewed for additional references and the search continued until the original description was found when possible.

STUDY SELECTION

All articles discussing the performance of the test or its validity (ie, sensitivity and specificity) were reviewed and summarized.

DATA EXTRACTION

Articles were reviewed for additional references and the search continued until the original description was found when possible.

DATA SYNTHESIS

The literature was reviewed, commonly used special tests for diagnosing ankle injuries were identified and described, distinguishing characteristics and limitations of each test were presented, and the current evidence for the clinical use of each test was discussed.

CONCLUSIONS

A complete physical examination is critical in the diagnosis of ankle injuries. The combination of available information such as mechanism of injury, all signs and symptoms, and changes in gait, is key to a conclusive and correct diagnosis. Clinicians should be aware of the severely limited evidence supporting the use of many commonly used special tests. Applying evidence from the literature will improve diagnostic accuracy. Further research is needed to understand the performance ability of special tests, both individually and when grouped as part of a test battery.

Posterior pilon fracture: Epidemiology and surgical technique

OBJECTIVES

To review a case series of patients with posterior pilon variant fracture using a novel approach, focusing on demographic data, injury pattern, surgical results based on computed tomography (CT) scan, and short-term complications.

DESIGN

Consecutive case series.

SETTING

Level I trauma center.

PATIENTS/PARTICIPANTS

Twenty-five patients with posterior pilon fracture.

INTERVENTION

Posterior pilon fracture open reduction and internal fixation.

MAIN OUTCOME MEASUREMENTS

Parameters measured included age, sex, type of fracture, surgical technique, anatomical reduction, and complications.

RESULTS

Twenty-five patients sustained a posterior pilon fracture, accounting for 13.4% of all operatively treated ankle fractures with median follow-up of 21.7 months. The average age of patients was 42 years (22-62); 19/25 (76%) were female, and 6/25 (24%) were male. A modified posteromedial approach was used in 18/25 (72%) patients. Persistent syndesmotic instability was present in 11/25 (44%) patients after posterior malleolar stabilization. Quality of reduction was assessed under CT scan in 19 patients, with 15/19 (78.9%) having anatomic reduction. We report 2/25 (8%) patients with early wound problems and 7/25 (20%) with short-term complications during follow-up.

CONCLUSION

Posterior pilon variant fracture appears to be less common than previously reported. Most fractures can be satisfactorily treated through a modified posteromedial approach. Albeit obtaining posterior malleolar fracture rigid fixation, syndesmotic instability was more prevalent than expected. The short-term complication rate was low.

LEVEL OF EVIDENCE

Therapeutic level IV.

Deltoid Ligament Rupture in Ankle Fracture: Diagnosis and Management

The last stage of a supination-external rotation ankle fracture involves either transverse fracture of the medial malleolus or rupture of the deltoid ligament. When the deltoid ligament ruptures, a "bimalleolar equivalent" ankle fracture occurs, and the surgeon is presented with several diagnostic and therapeutic challenges. In the native ankle, the deltoid ligament provides restraint to eversion and external rotation of the talus on the tibia. In bimalleolar equivalent ankle fractures, there is often gross medial instability even after fibular reduction. Retraction of the deltoid with subsequent healing in a nonanatomic position theoretically may cause instability, persistent medial gutter pain, and loss of function with risk of early arthritis. In mild cases, deltoid injury may not be obvious, and potential diagnostic techniques include preoperative and intraoperative stress radiography, MRI, and ultrasonography. The most common injury pattern is avulsion from the medial malleolus, and most current repair techniques involve direct repair of the capsular and deltoid injuries involving suture anchors in the medial malleolus and imbrication of the superficial and deep deltoid fibers. To date, there is limited evidence of superior clinical outcomes with the addition of deltoid repair compared with open reduction and internal fixation of the fibula alone.

Intraoperative tap test for coronal syndesmotic instability: A cadaveric study

INTRODUCTION

Precise diagnosis of distal tibiofibular syndesmotic injury is challenging, and a gold standard diagnostic test has still not been established. Tibiofibular clear space identified on radiographic imaging is considered the most reliable indicator of the injury. The Cotton test is the most widely used intraoperative technique to evaluate the syndesmotic integrity although it has its limitations. We advocate for a novel intra operative test using a 3.5 mm blunt cortical tap.

METHODS

Tibiofibular clear space was assessed in nine cadaveric specimens using three sequential fluoroscopic images. The first image was taken prior to the application of the tap test (intact, non-stressed). Then, a 2.5 mm hole was drilled distally on the lateral fibula, and a 3.5 mm cortical tap was then threaded in the hole. The tap test involved gradually advancing the blunt tip against the lateral tibia, providing a tibiofibular separation force (intact, stressed). This same stress was then applied after all syndesmotic ligaments were released (injured, stressed). Measurements were compared by one-way ANOVA and paired Student's t-test. Intra and inter-observer agreements were evaluated by intraclass correlation coefficient (ICC). P-values <.05 were considered significant.

RESULTS

We found excellent intra-observer (0.97) and inter-observer (0.98) agreement following the imaging assessment. Significant differences were found in the paired comparison between the groups (p < .05). When using an absolute value for TFCS >6 mm as diagnostic for coronal syndesmotic instability, the tap test demonstrated a 96.3% sensitivity and specificity, a 96.3% PPV and NPV and a 96.3% accuracy in diagnosing coronal syndesmotic instability.

CONCLUSIONS

Our cadaveric study demonstrated that this novel coronal syndesmotic instability test using a 3.5 mm blunt cortical tap is a simple, accurate and reliable technique able to demonstrate significant differences in the tibiofibular clear space when injury was present. It could represent a more controlled and stable alternative to the most used Cotton test.

Short-Term Results of a Ruptured Deltoid Ligament Repair During an Acute Ankle Fracture Fixation

BACKGROUND

There is no consensus on the optimal treatment or preferred method of operation for the management of acute deltoid ligament injuries during an ankle fracture fixation. This study aimed to analyze the outcomes of repairing the deltoid ligament during the fixation of an ankle fracture compared to conservative management.

METHODS

We retrospectively evaluated 78 consecutive cases of a ruptured deltoid ligament with an associated ankle fracture between 2001 and 2016. All of the ankle fractures were treated with a plate and screw fixation. Patients in the conservative treatment for ruptured deltoid ligament underwent management from 2001 to 2008 (37 fractures, group 1), while the operative treatment for ruptured deltoid ligament was included from 2009 to 2016 (41 fractures, group 2). The outcome measures included radiographic findings, the American Orthopaedic Foot & Ankle Society ankle-hindfoot scores, visual analog scale scores, and the Foot Function Index. All patients were followed for an average of 17 months.

RESULTS

Radiologic findings in both groups were comparable, but the final follow-up of the medial clear space (MCS) was significantly smaller in the group 2 ( P < .01). Clinical outcomes were similar between the two groups ( P > .05). Comparing those who underwent syndesmotic fixation between both groups, group 2 showed a significantly smaller final follow-up MCS, and all clinical outcomes were better in group 2 ( P < .05). Linear regression analysis showed that the final follow-up MCS had a significant influence on clinical outcomes ( P < .05).

CONCLUSION

Although the clinical outcomes were not significantly different between the 2 groups, we obtained a more favorable final follow-up MCS in the deltoid repair group. Particularly when accompanied by a syndesmotic injury, the final follow-up MCS and the clinical outcomes were better in the deltoid repair group. In the case of high-grade unstable fractures of the ankle with syndesmotic instability, a direct repair of the deltoid ligament was adequate for restoring medial stability.

LEVEL OF EVIDENCE

Level III, retrospective comparative case series.

Medial Clamp Tine Positioning Affects Ankle Syndesmosis Malreduction

OBJECTIVES

To determine whether the position of the medial clamp tine during syndesmotic reduction affected reduction accuracy.

DESIGN

Prospective cohort.

SETTING

Urban Level 1 trauma center.

PATIENTS

Seventy-two patients with operatively treated syndesmotic injuries.

INTERVENTION

Patients underwent operative fixation of their ankle syndesmotic injuries using reduction forceps. The position of the medial clamp tine was then recorded with intraoperative fluoroscopy. Malreduction rates were then assessed with bilateral ankle computerized tomography.

MAIN OUTCOME MEASUREMENT

Fibular position within the incisura was measured with respect to the uninjured side to determine whether a malreduction had occurred. Malreductions were then analyzed for associations with injury pattern, patient demographics, and the location of the medial clamp tine.

RESULTS

A statistically significant association was found between medial clamp position and sagittal plane syndesmosis malreduction. In reference to anterior fibular translation, there was a 0% malreduction rate in the 18 patients where the clamp tine was placed in the anterior third, a 19.4% malreduction rate in the middle third, and 60% malreduction rate in the posterior third (P = 0.006). In reference to posterior fibular translation, there was a 11.1% malreduction when clamp placement was in the anterior third, a 16.1% malreduction rate in the middle third, and 60% malreduction rate in the posterior third (P = 0.062). There were no significant associations between medial clamp position and coronal plane malreductions (overcompression or undercompression) (P = 1).

CONCLUSIONS

When using reduction forceps for syndesmotic reduction, the position of the medial clamp tine can be highly variable. The angle created with off-axis syndesmotic clamping is likely a major culprit in iatrogenic malreduction. Sagittal plane malreduction appears to be highly sensitive to clamp obliquity, which is directly related to the medial clamp tine placement. Based on these data, we recommend placing the medial clamp tine in the anterior third of the tibial line on the lateral view to minimize malreduction risk.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Open reduction and internal fixation of posterior malleolar fractures using the posterolateral approach

Aims

Involvement of the posterior malleolus in fractures of the ankle probably adversely affects the functional outcome and may be associated with the development of post-traumatic osteoarthritis. Anatomical reduction is a predictor of a successful outcome. The purpose of this study was to describe the technique and short-term outcome of patients with trimalleolar fractures, who were treated surgically using a posterolateral approach in our hospital between 2010 and 2014.

Patients and Methods

The study involved 52 patients. Their mean age was 49 years (22 to 79). There were 41 (79%) AO 44B-type and 11 (21%) 44C-type fractures. The mean size of the posterior fragment was 27% (10% to 52%) of the tibiotalar joint surface.

Results

Reduction was anatomical in all patients with a residual step in the articular surface of ≤ 1 mm. In nine of the C-type fractures (82%), the syndesmosis was stable after fixation of the posterior fragment and a syndesmosis screw was not required. Apart from one superficial wound infection, there were no wound healing problems. At a mean radiological follow-up of 34 weeks (seven to 131), one patient with a 44C-type fracture had widening of the syndesmosis which required further surgery.

Conclusion

We conclude that the posterolateral surgical approach to the ankle gives adequate access to the posterior malleolus, allowing its anatomical reduction and stable fixation: it has few complications. Take home message: Fixation of the posterior malleolus in trimalleolar fractures can be easily done via the posterolateral approach whereby anatomical reduction and stable fixation can be reached due to adequate visualisation of the fracture. Cite this article: Bone Joint J 2016;98-B:812–17.

Intraoperative syndesmotic reduction: three-dimensional versus standard fluoroscopic imaging

BACKGROUND

The quality of reduction of the syndesmosis is an important factor in the outcome of ankle fractures associated with a syndesmotic injury. The purpose of this study was to directly compare the accuracy of syndesmotic reductions obtained using intraoperative standard fluoroscopic techniques against reductions obtained using three-dimensional imaging of the Iso-C3D fluoroscope.

METHODS

We prospectively reviewed imaging studies of patients who were diagnosed as having preoperative or intraoperative evidence of syndesmotic diastasis (on the basis of the fluoroscopic Cotton test and/or a manual external rotation stress test) who underwent syndesmotic fixation at one of two level-I trauma centers. Center A used intraoperative computed tomography (CT) imaging to assess reduction (≤2 mm), while Center B assessed reduction under standard fluoroscopic imaging. Postoperative alignment was assessed in a standardized manner, measuring anterior fibular distance, posterior fibular distance, and the anterior translation distance. Measurements were taken on the injured side and the uninjured side and compared between the groups on postoperative axial CT scans.

RESULTS

A total of thirty-six patients in both centers met our inclusion criteria and were included in the data analysis. Despite utilization of the Iso-C(3D), a high rate of malreductions was noted in both groups. Anterior translation distance malreductions occurred in 31% of the sixteen patients in Center A and 25% of the twenty patients in Center B (p = 0.72). The number of anterior fibular distance malreductions was similar, with a rate of 38% in Center A and 30% in Center B (p = 0.73). A significant difference among the centers (p = 0.03) was noted, however, when the posterior fibular distance data was analyzed, with 6% being malreduced by >2 mm in Center A and 40% in Center B.

CONCLUSIONS

The results of our study support previous investigations that have cited high rates of syndesmotic malreductions and demonstrate that the addition of advanced intraoperative imaging techniques does not help to reduce the rate of malreductions in this cohort.

Does the Arthrex TightRope® provide maintenance of the distal tibiofibular syndesmosis? A 2-year follow-up of 64 TightRopes® in 37 patients

Syndesmotic diastasis can occur as an isolated injury or with concomitant fractures. A review of 37 patients with 64 TightRopes® for syndesmotic repair was performed, with a mean follow-up of 23.6 ± 4.3 months, from 2007 to 2011. The patients' mean age was 40.67 (range 14 to 87) years. The mean initial measurements were as follows: tibiofibular clear space (TFCS) = 4.1 ± 1.1 mm, tibiofibular overlap (TFO) = 7.2 ± 2.7 mm, and medial clear space (MCS) = 2.9 ± 0.5 mm. The mean final measurements were as follows: TFCS = 4.2 ± 1.3 mm, TFO = 7.4 2.8 mm, and MCS = 3.0 0.5 mm. The calculated measurable difference from the initial to final TFCS, TFO, and MCS was significantly less than the maximum threshold for allowable widening of the syndesmosis: TFCS, p < .001; TFO, p < .002; and MCS, p < .001. Complications occurred in 10 patients; 7 (19%) experienced knot irritation and 3 (8%) developed an infection. The mean interval to weightbearing was 33.2 ± 12.7 days. The mean postoperative American Orthopaedic Foot and Ankle Society score was 97 (range 90 to 100). Of 64 suture endobuttons, 4 (6.25%) required removal. The fracture types were as follows: 3 (8%) isolated syndesmotic injuries, 9 (24%) trimalleolar fractures, 10 (27%) bimalleolar fractures, 7 (18%) Weber B fractures, 3 (8%) Weber C fractures, 1 (3%) Salter Harris type 3 fracture, and 4 (11%) Maisonneuve fractures. TightRope® fixation was advantageous because it rarely required removal, allowed for physiologic motion of the syndesmosis, and resulted in an early return to weightbearing. In addition, we have concluded that the TightRope® provides long-term stability of the ankle mortise, which was confirmed by the radiographic criteria and excellent American Orthopaedic Foot and Ankle Society scores.

Treatment of the stress positive ligamentous SE4 ankle fracture: incidence of syndesmotic injury and clinical decision making

OBJECTIVES

The objective of the study was to review our experience with the treatment of stress positive (+) supination and external pattern injuries using shared decision making with the patients.

DESIGN

Retrospective case review.

SETTING

Level 1 trauma center.

PATIENTS

Over a 9-year period, we treated 114 patients (aged 19-76 years, average 43 years) with stress (+) supination and external rotation type fibula fractures, who were included in the present study.

INTERVENTION

X-rays were reviewed, and the medial clear space (MCS) measured on the presentation, stress, and final united radiographs. The decision for surgical or nonsurgical management was made by the patient and surgeon after a discussion of risks/benefits of both. Syndesmotic instability for the operative cases was diagnosed by medial widening and talar subluxation on abduction/external rotation stress after fibular fixation.

MAIN OUTCOME MEASURE

MCS measurement at union.

RESULTS

Of the 114 cases, 54 were definitively treated in a cast, and 60 were treated operatively. Twenty-seven (45%) of the operative cases demonstrated syndesmotic instability on radiographic examination. The MCS on stress examination was statistically different, with greater widening seen for operatively treated patients (4.8 ± 0.5 vs. 6.9 ± 0.86) (P < 0.001). No patient healed with any subluxation on weight bearing x-rays.

CONCLUSIONS

Stress (+) SE pattern fibular fractures with minimal MCS widening on stress examination may be treated in a cast to union with predictable healing. In those patients treated operatively, the treating surgeon should be aware of the high rate of syndesmotic injury.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Bolt fixation for syndesmotic injuries

We performed a retrospective study of 28 patients who underwent bolt fixation for a syndesmotic injury to the ankle. The mean follow-up period was 66 months (range: 24-139 months). The results of surgery were assessed clinically and radiographically. Overall, this fixation device was found to adequately stabilise the syndesmosis during healing. Radiologically accurate syndesmosis reduction was achieved in 26 patients. The mean AOFAS score was 86 (range: 33-100). The majority of patients were very satisfied with the overall result. It is a simple and quick operative procedure providing reliable syndesmotic reduction. The material should not be removed prior to walking. The only drawback is the greater need for removal in the event of local symptoms.

Which ankle fractures require syndesmotic stabilization?

Syndesmotic ruptures associated with ankle fractures are most commonly caused by external rotation of the foot, eversion of the talus within the ankle mortise, and excessive dorsiflexion. The distal tibiofibular syndesmosis consists of the anterior inferior tibiofibular ligament, posterior inferior tibiofibular ligament, and interosseous ligament, and it is essential for stability of the ankle mortise. Despite the numerous biomechanical and clinical studies pertaining to ankle fractures, there are no uniform recommendations regarding the use of the syndesmotic screw for specific injury patterns and fracture types. The objective of this review was to formulate recommendations for clinical practice related to the use of syndesmotic screw placement.

Intraoperative diagnosis of syndesmosis injuries in external rotation ankle fractures

OBJECTIVE

This study was designed to compare intraoperative fluoroscopic stress testing, static radiographs, and biomechanical criteria for the diagnosis of distal tibiofibular syndesmotic instability associated with external rotation type ankle fractures.

DESIGN

Prospective, consecutive series.

SETTING

Academic level 1 trauma center.

PATIENTS/PARTICIPANTS

Thirty-eight skeletally mature patients with unstable unilateral external rotation ankle fractures were prospectively recruited.

INTERVENTION

Before surgery, the treating surgeon detailed the operative treatment plan, including need for syndesmotic fixation. In pronation-external rotation injuries, biomechanical criteria were applied to predict syndesmotic instability. Ankles were examined using intraoperative fluoroscopic external rotation stress tests. The contralateral uninjured limb was used as a control. A 7.2-Nm force was applied for the external rotation stress examination. Stress testing was performed after lateral malleolar fixation and repeated after medial and syndesmotic fixation.

MAIN OUTCOME MEASURES

The incidence of syndesmotic instability was determined based on radiographic clear space measurements and compared with previously published criteria.

RESULTS

Intraoperative fluoroscopy detected unpredicted syndesmotic instability in 37% of ankles. In supination-external rotation (OTA 44B) injuries, unpredicted syndesmosis instability was found in 10 of 30 patients (33%). In pronation-external rotation injuries (OTA 44C), 4 of 7 patients (57%) were associated with syndesmosis disruption not predicted by biomechanical criteria. In bimalleolar fractures, syndesmosis fixation improved stability compared with rigid bimalleolar fixation alone (P < 0.01).

CONCLUSIONS

Preoperative radiographs and biomechanical criteria are unable to routinely predict the presence or absence of syndesmosis instability. Rigid bimalleolar fixation was frequently not sufficient to stabilize syndesmotic disruption. Intraoperative stress fluoroscopy is a valuable tool for detection of unstable syndesmotic injuries.