Weightbearing Radiographs Facilitate Functional Treatment of Ankle Fractures of Uncertain Stability

Trends in the Use of Weightbearing Computed Tomography

Background: This review aimed to critically appraise the most recent orthopedic literature around cone beam weightbearing computed tomography (WBCT), summarizing what evidence has been provided so far and identifying the main research trends in the area. Methods: This scoping review was performed on studies published between January 2013 and December 2023 on the Pubmed database. All studies (both clinical and nonclinical) in which WBCT had been used were critically analyzed to extract the aim (or aims) of the study, and the main findings related to the role of this imaging modality in the diagnostic pathway. Results: Out of 1759 studies, 129 were selected. One hundred five manuscripts (81%) dealt with elective orthopedic conditions. The majority of the analyses (88 studies; 84%) were performed on foot and ankle conditions, while 13 (12%) studies looked at knee pathologies. There was a progressive increase in the number of studies published over the years. Progressive Collapsing Foot Deformity (22 studies; 25%) and Hallux Valgus (19 studies; 21%) were frequent subjects. Twenty-four (19%) manuscripts dealt with traumatic conditions. A particular interest in syndesmotic injuries was documented (12 studies; 60%). Conclusions: In this review, we documented an increasing interest in clinical applications of weightbearing CT in the orthopedic field between 2013 and 2023. The majority of the analyses focused on conditions related to the foot and the ankle; however, we found several works investigating the value of WBCT on other joints (in particular, the knee).

The value of radiologic diagnostics in evaluating deltoid integrity in isolated type B ankle fractures: a systematic review of the literature

INTRODUCTION

Excluding deep deltoid ligament (DDL) rupture in isolated type B ankle fractures is crucial in the decision-making process for surgical or conservative treatment. There is no consensus about the most accurate radiologic diagnostic test to determine medial injury. The aim of this study is to systematically review the literature concerning radiologic diagnostics that evaluate medial injury in adult patients with isolated type B ankle fractures.

METHODS

The electronic databases PubMed, Embase, Web of Science, COCHRANE Library, and Emcare were searched to identify studies published from January 1990 to December 2020 concerning sensitivity and specificity of diagnostic tests that evaluate medial injury in patients with an isolated type B ankle fracture. For inclusion, comparison to a reference test was required to provide results in terms of sensitivity, specificity, and preferably positive predictive value and negative predictive value RESULTS: This review included 8 studies. Ultrasound showed the highest sensitivity of 100% and a specificity between 90 and 100% for detecting DDL rupture. Gravity stress radiographs showed a sensitivity of 71-100% and a specificity between 88 and 92%. The mortise, external rotation stress test, and MRI had lower sensitivity and specificity values, between 65 and 88%.

CONCLUSION

The most accurate and available methods for diagnosing deltoid integrity seem to be the ultrasound and the GS radiograph. Further research is needed to confirm the results of this review.

Lack of Displacement of the Fibula Is Not a Confirmation of Ankle Stability in Supination External Pattern Ankle Fractures

OBJECTIVES

To evaluate and compare radiographic findings in supination external (SE)2 injuries versus stress (+) SE4 injuries.

DESIGN

Retrospective.

SETTING

Academic Level 1 trauma center.

PATIENTS

The study included 350 skeletally mature patients at a single Level 1 trauma center who presented with an isolated, Lauge-Hansen type supination-external rotation pattern, Weber B lateral malleolar fracture, OTA/AO 44-B.

RESULTS

We reviewed 350 patients (185 men and 165 women), 18-95 years of age (avg 45), with isolated SE pattern lateral malleolar fractures. One hundred nine had SE4 injuries [medial clear space (MCS) = 8.3 mm]. Two hundred forty-one ankles were stressed; 164 were unstable and 77 were stable (SE2). Avg MCS at presentation and on stress radiographs was 3.59 mm for the SE2 (no widening) and 3.86 mm and 5.94 mm for the stress (+) SE4 group, respectively. The fibular displacement for the SE2, stress (+) SE4, and SE4 groups was 1.5 (0-4.5), 3.5 (0-6.6), and 4.1 (0-30.5), respectively. Sixteen of the 77 (20%) SE2 and 24 of the 164 (15%) stress (+) SE4 fractures had no displacement of the fibula on the lateral view. Similarly, 53 of the 77 (68%) SE2 and 91 of the 164 (55%) stress (+) SE4 had ≤2 mm of fibular displacement Fibular displacement of ≤2 mm on the lateral radiograph corresponded with 0.69 sensitivity and only 0.37 positive predictive value for stable ankle mortise on stress examination.

CONCLUSIONS

Previous work indicated that patients with an isolated SE pattern fibula fracture, a normal MCS, and ≤2 mm of fibular displacement on the lateral radiograph have a high rate of ankle stability, with a positive predictive value of approximately 97%. We were unable to confirm this finding because 15% of unstable ankles had 0 mm and 55% had ≤2 mm of fibular displacement. We conclude that stability may not be inferred from a lack of fibular displacement on the lateral view in this population of patients. If stability is to be determined, it must be tested irrespective of fibular displacement on the lateral radiograph.

LEVEL OF EVIDENCE

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

Functional bracing is a safe and cost effective treatment for isolated Weber B fracture

BACKGROUND

Despite the current recommendations that stable Weber B ankle fractures can be treated with functional bracing and weightbearing as tolerated, some reluctance exists among trauma surgeons to follow these recommendations. This paper reports on our institution's experience in managing these injuries and compare it to the national guidelines.

PATIENTS AND METHODS

This is a retrospective cohort study. Consecutive patients with isolated Weber B fractures referred to the local outpatient clinic over the period of six months were included in the study. Radiographs and clinic letters were examined, the patients were interviewed via telephone to obtain outcome scores [Olerud and Molander score]. Method of immobilisation, weight-bearing status, radiological fracture union, clinical outcomes and complications were all assessed and analysed.

RESULTS

One hundred and twenty-three patients with isolated Weber B fractures were identified. This cohort of patients did not show clinical or radiographic evidence of instability, they were deemed stable and were initially treated non-operatively. Minimum follow-up period was six months. Sixty-two patients were treated in plaster and were non-weight bearing on the affected limb, while 61 were treated with functional bracing in a boot and were allowed early weight bearing. Three patients showed displacement requiring surgical fixation. All fractures progressed to union and patients were discharged irrespective of the method of immobilisation or weightbearing status during treatment. There was no statistically significant difference in the functional outcome measures between the two groups. The protocol of functional bracing and weightbearing was associated with fewer outpatient clinics and a reduced number of radiographs obtained in the clinic and fewer complications.

CONCLUSION

Isolated trans-syndesmotic Weber B ankle fractures, that are clinically and radiologically stable, can be safely treated with functional bracing in a boot and weightbearing as tolerated.

The Value of Additional Gravity Stress Radiographs for Decision Making in the Treatment of Isolated Type B Distal Fibular Fractures

BACKGROUND

Prior to treatment decisions concerning isolated Weber type B ankle fractures, assessment of the stability of the ankle joint is mandatory. The gravity stress (GS) radiograph is a radiographic tool to determine stability. We hypothesized that this additional GS radiograph would lead to fewer operative treatments by applying the criterion of operative treatment when medial clear space (MCS) > superior clear space (SCS) + 2 mm on the GS radiograph, compared with the nonstressed mortise view criteria of advising operative treatment in case of MCS > SCS + 1 mm.

METHODS

This retrospective comparative cohort study analyzed 343 patients aged between 18 and 70 years with an isolated Weber type B ankle fracture diagnosed at the emergency department between January 2014 and December 2019. The cohort was divided into 2 groups based on whether an additional GS radiograph was performed. Group I consisted of 151 patients in whom a regular mortise and lateral radiograph were performed. Group II comprised 192 patients, with an additional GS radiograph. Primary outcome was type of treatment (conservative vs operative). Secondary outcomes were patient-reported functional outcomes and pain.

RESULTS

Baseline characteristics of both groups did not differ. In group I, surgery was performed in 60 patients (39.7%) compared with 108 patients (56.3%) in group II (P = .002). In the operatively treated patients, the mean MCS on regular mortise view was significantly smaller in patients in whom an additional GS radiograph was performed compared to patients without an additional GS radiograph (4.1 mm vs 5.2 mm, P < .001). Mean Olerud-Molander Ankle Score and mean visual analog scale (VAS) for pain did not differ significantly between groups I and II.

CONCLUSIONS

Contrary to what was hypothesized, the introduction of an additional gravity stress radiograph, by which operative treatment was indicated if the MCS was wider than the SCS + 2 mm, did not result in reduced operative treatment of Weber type B ankle fractures when operative treatment was indicated for MCS > SCS + 1 mm on non-gravity stress radiographs.

LEVEL OF EVIDENCE

Level III: retrospective comparative study.

The additional value of weight-bearing and gravity stress ankle radiographs in determining stability of isolated type B ankle fractures

GOAL

The aim of this study is to investigate whether weight-bearing and gravity stress radiographs have additional value in predicting concomitant deep deltoid ligamentous (DDL) injury in case of isolated Weber type B fibular fractures. This may help to make the clinically relevant distinction between unstable fractures and fractures that can be treated conservatively.

METHODS

In this prospective cohort study, 90 patients with an isolated type B ankle fracture, without a medial or posterior fracture, and a medial clear space (MCS) < 6 mm on the regular mortise (RM) view were included. In all patients, an additional gravity stress (GS) view and an MRI scan were performed. Furthermore, in 51 patients, an additional weight-bearing (WB) radiograph was performed. The MCS and superior clear space (SCS) measurements of these radiographs were compared with MRI findings to measure sensitivity and specificity in excluding deep deltoid ligament (DDL) rupture.

RESULTS

The mean MCS on the RM view was 3.32 mm (1.73-5.93) compared to 4.75 mm (2.33-10.40) on the GS view and 3.18 mm (1.93-6.9) on the WB radiograph. MRI showed a high-grade or complete deltoid ligament tear in 25 (28%) patients. Using an MCS cut-off value of ≥ SCS + 2 mm, the RM view showed 0% sensitivity and 97% specificity in diagnosing a DDL rupture. Both the GS view (with MCS ≥ SCS + 3 mm as cut-off value) and the WB radiograph (with cut-off value MCS ≥ SCS + 2 mm) showed 6% sensitivity and 100% specificity.

CONCLUSION

The gravity stress and weight-bearing radiograph can accurately exclude DDL injury. They might have extra value in addition to the conventional mortise view in assessing the stability of isolated type B ankle fractures. This helps in deciding whether patients should be selected for operative or safe conservative treatment.

Fibula fractures management

Isolated distal fibula fractures represent the majority of ankle fractures. These fractures are often the result of a low-energy trauma with external rotation and supination mechanism. Diagnosis is based on clinical signs and radiographic exam. Stress X-rays have a role in detecting associated mortise instability. Management depends on fracture type, displacement and associated ankle instability. For simple, minimally displaced fractures without ankle instability, conservative treatment leads to excellent results. Conservative treatment must also be considered in overaged unhealthy patients, even in unstable fractures. Surgical treatment is indicated when fracture or ankle instability are present, with several techniques described. Outcome is excellent in most cases. Complications regarding wound healing are frequent, especially with plate fixation, whereas other complications are uncommon.

Imaging Techniques for Assessment of Dynamically Unstable Sports Related Foot and Ankle Injuries

Foot and ankle instability can be seen both in acute and chronic settings, and isolating the diagnosis can be difficult. Imaging can contribute to the clinical presentation not only by identifying abnormal morphology of various supporting soft tissue structures but also by providing referring clinicians with a sense of how functionally incompetent those structures are by utilizing weight-bearing images and with comparison to the contralateral side. Loading the affected joint and visualizing changes in alignment provide clinicians with information regarding the severity of the abnormality and, therefore, how it should be managed.

[Nonoperative treatment of isolated fractures of the distal fibula]

Stable ankle fractures can be successfully managed nonoperatively. Unstable fractures on the other hand should be treated surgically as operative management consistently leads to better outcomes. How to define stability in ankle fractures continues to be a controversial issue. Better understanding of the mechanism of injury as well as improved knowledge of ankle biomechanics now enables surgeons to define stability after isolated fractures of the distal fibula with high accuracy. The following article describes commonly used methods to assess ankle stability after isolated fractures of the lateral malleolus, including stress tests and the use of weight-bearing radiographs. By adhering to the described criteria more than 90% of all isolated nondisplaced fractures of the distal fibula can be managed nonoperatively with excellent results.

Customized Three-Dimensional-Printed Orthopedic Close Contact Casts for the Treatment of Stable Ankle Fractures: Finite Element Analysis and a Pilot Study

Ankle fracture is one of the most common traumatic fractures among the elderly population. The majority of ankle fractures are stable types with the typically conservative strategy of close contact casting treatment. The continuous use of unventilated standard cast immobilization severely affects patient's satisfaction and compliance and markedly increases the rates of various complications. Three-dimensional (3D) printing for casts has advantages of lightweight, ventilated, proper-fit, and esthetic improvements. In this work, this novel 3D-printed cast has been applied to individuals with stable ankle fractures, and its effectiveness can be successfully validated with finite element analysis and a pilot study. A 30% reduction of the volume was chosen as the optimal result in topology optimization. Both 3D-printed casts and conventional casts showed significant ankle function improvement after immobilization for 6 weeks (p = 0.000). The 3D-printed casts were superior to the traditional casts in Olerud-Molander Ankle Scores (OMAS), with the mean difference of 8.3 ± 8.57 OMAS points (95% CI -10.8 to 27.5; p = 0.354) for 6 weeks, implying that the 3D-printed casts possibly maintain the equal clinical efficacy as the traditional casts. The statistically significant difference between groups from the 3D-printed cast and the traditional one observed in C-QUEST 2.0 was 11.3 ± 1.5 points (95% CI 8.0-14.6; p = 0.000), indicating that the 3D-printed cast possesses outperforming satisfaction and compliance and has great potential in practical applications. There were no severe complications in the 3D-printed casts, but more moderate complications were observed in the traditional casts.

Ankle fractures in the elderly: Current concepts

Ankle fractures remain the third most common musculoskeletal injury in the elderly population. The presence of osteoporosis, significant multiple comorbidities and limited functional independence makes treatment of such injuries challenging. Early studies highlighted high rates of post-operative complications and poor outcomes after surgical intervention. With advances in surgical techniques and a greater understanding of multi-disciplinary team (MDT)-driven peri-operative care and rehabilitation, evidence now appears to suggest improved outcomes for operative management. Approaches must be adapted according to co-morbidities, baseline function and patient wishes. This review article aims to discuss contemporary treatment strategies and the complex challenges associated with the management of the elderly ankle fracture.

ACR Appropriateness Criteria® Acute Trauma to the Ankle

Acute injuries to the ankle are frequently encountered in the setting of the emergency room, sport, and general practice. This ACR Appropriateness Criteria defines best practices for imaging evaluation for several variants of patients presenting with acute ankle trauma. The variants include scenarios when Ottawa Rules can be evaluated, when there are exclusionary criteria, when Ottawa Rules cannot be evaluated, as well as specific injuries. Clinical scenarios are followed by the imaging choices and their appropriateness with an accompanying narrative explanation to help physicians to order the most appropriate imaging test. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Effect of Muscle Activation on the Gravity Stress View in Unstable Weber B Ankle Fractures

BACKGROUND

In the setting of apparently isolated distal fibula fractures, the gravity stress view (GSV) is a validated method to determine mortise stability. There is currently no published data evaluating whether dynamic muscle activation can reduce an unstable mortise. If patients with instability can overcome gravity, resultant images could yield false-negative results. The goal of this investigation was to determine if patient effort can influence medial clear space (MCS) measurements in proven unstable bimalleolar-equivalent ankle fractures.

METHODS

Patients presenting with Weber B fibula fractures were assessed for mortise stability using the GSV. If the GSV demonstrated instability based on MCS widening >4 mm, 3 additional views were performed: GSV with an assistant maintaining the ankle in a neutral position; GSV with the patient actively dorsiflexing to neutral; and GSV with the patient actively dorsiflexing and supinating the foot. Twenty-four consecutive patients met inclusion criteria, with a mean age of 48.7 (range, 22-85) years. Fifteen patients (62.5%) were female and 9 (37.5%) were male. The laterality was evenly divided.

RESULTS

The mean MCS was 5.8 ± 2.0 6.0 ± 2.6, and 6.2 ± 2.7 mm for the manual assist, active dorsiflexion, and active supination radiograph measurement groups, respectively (P = .434). Only 5 of 24 subjects had any measurable decrease in their MCS with active supination, with a maximum change of 1.2 mm. The remainder of the patients had an increase in MCS ranging from 0.1 to 4.0 mm.

CONCLUSION

There was no significant difference between measurement states indicating that muscle activation is unlikely to yield a false-negative result on GSV. Mortise instability, secondary to deep deltoid injury in the presence of gravity stress, is unlikely to be actively overcome by dynamic stabilizers, supporting the validity and specificity of the GSV.

LEVEL OF EVIDENCE

Level III, prospective study.

Medial tenderness revisited: Is medial ankle tenderness predictive of instability in isolated lateral malleolus fractures?

INTRODUCTION

Determining deltoid ligament incompetence in supination external rotation (SER) injuries commonly relies on stress radiography, given several studies demonstrating low predictive value of physical examination. Stress radiography can be difficult to obtain and may result in suboptimal radiographs with equivocal determination of stability. This study revisits the concept of medial ankle tenderness and its association with mortise instability.

METHODS

Patients who presented with an isolated lateral malleolus fracture underwent prospective data collection. VAS scores were recorded with palpation at the lateral malleolar fracture site, anterior deltoid ligament, and posterior deltoid ligament. Three non-weightbearing radiographs of the ankle and a gravity stress view were obtained. Statistical analysis was performed to determine a correlation between tenderness and instability defined as MCS widening > 4 mm on gravity stress x-ray.

RESULTS

51 patients met inclusion criteria. Group I (stable) and Group II (unstable) demonstrated no difference in tenderness over the lateral malleolus (p = 0.94) or anterior deltoid (p = 0.12), but patients in Group II reported significantly more tenderness over the posterior deltoid (p = 0.03). Taking the higher pain score from either anterior or posterior deltoid palpation, patients with unstable ankle fractures reported significantly more tenderness with medial palpation (p = 0.02). The relative risk of having an unstable ankle fracture with any tenderness to palpation over either the anterior or posterior deltoid ligament was 1.77 (95% CI 1.03 - 3.06, P = 0.039). When comparing no pain versus the presence of any pain with palpation medially, the sensitivity for any medial tenderness to detect an unstable ankle fracture was 0.76 (specificity 0.59, PPV 0.79, NPV 0.56).

CONCLUSION

Patients with any medial tenderness were at significantly higher risk of having an unstable SER ankle fracture in this study, but strict reliance on the presence or absence of medial tenderness without stress radiographs would lead to an unacceptable number of both false positive and false negative determinations of instability. However, our findings suggest that medial tenderness is associated with instability. The 0.79 PPV of any medial tenderness for instability may be useful to cast doubt on equivocal stress radiography and prompt surgeons to repeat stress radiography or shorten the interval for radiographic follow up.

LEVEL OF EVIDENCE

Diagnostic study, Level II-1 (development of diagnostic criteria on basis of consecutive patients [with universally applied reference "gold" standard]).

Long-term outcome in operatively and non-operatively treated isolated type B fibula fractures

PURPOSE

Type B fibula fractures are the most common type of ankle fractures. Generally, surgical repair is advised for unstable fractures and non-operative treatment for stable fractures. However, evidence on long-term functional outcome of both treatment regimens is lacking. Aim of this study is to compare the long-term outcome in function and pain between patients with an isolated type B fibula fracture treated non-operatively and surgically.

MATERIAL & METHODS

In this retrospective cohort study, all consecutive patients aged between 18 and 75 years, treated non-operatively or surgically between January 2008 and December 2015 for a distal fibula fracture at the level of the syndesmosis without an additional medial or posterior fracture and with a medial clear space ≤6 mm were included. All eligible patients received a questionnaire, composed of the Olerud-Molander Ankle Score (OMAS), the American Orthopaedic Foot and Ankle Society ankle-hindfoot score (AOFAS), the Euroqol-5D (EQ-5D) for quality of life and the Visual Analogue Scale (VAS) for pain sensation. With a mean follow-up of 5.3 years, 229 patients were included. For all aspects of the questionnaire, there was no significant difference between non-operative and operative treatment in outcome of function and pain: the EQ-5D score was respectively 0.8 vs. 0.9 (p = 0.72), mean VAS score 0.8 vs. 1.3 (p = 0.09), OMA score 84 vs. 84 (p = 0.98) and for the AOFAS 93 vs. 90 (p = 0.28). 33% of the patients who had surgery had revision surgery for implant removal because of persistent pain complaints. In 3% of the surgically treated patients, a wound infection required intravenous antibiotic treatment. In the non-operatively treated cohort, one patient developed a deep venous thrombosis in the fractured leg.

CONCLUSION

According to results of this study, in adult patients with an isolated distal fibula and medial clear space ≤6 mm, without proven instability these fractures can safely be treated non-operatively, while avoiding risks and costs of surgery and preserving good long-term outcome in terms of pain and function.

Systematic Review of Stress Radiographic Modalities Stability Assessment in Supination External Rotation Ankle Fractures

Background:

Isolated distal fibular fractures resulting from supination external rotation (SER) injuries without evidence of obvious talar shift on standard radiographs present a diagnostic dilemma for clinicians. The status of the deep deltoid ligament, the main stabilizer of the ankle joint, is assessed by an increase in medial clear space (MCS) on radiographs. Therefore, these injuries can be either stable or unstable. In recent years, considerable clinical and research efforts have been made to determine ankle stability following SER fracture. The purpose of this systematic review was to evaluate and compare the role of different stress radiograph modalities in assessing stability of the ankle with SER fractures with no obvious talar subluxation on standard radiographs.

Methods:

The electronic databases MEDLINE, EMBASE, Ovid, Cochrane Central, CINAHL, and Google Scholar were searched from January 2000 to January 2018 to identify literature relating to radiologic assessment of stability of SER ankle fractures.

Results:

Our literature search revealed 10 peer-reviewed articles that fulfilled inclusion criteria. This yielded a total of 698 patients. The systematic review found 3 broad categories of radiographic investigations in the assessment of ankle joint stability: external rotation (ER) stress radiographs, gravity stress views (GSV), and weightbearing (WB) radiographs. Proponents of WB radiographs have demonstrated how axial load can normalize ankle joint alignment in cases of proven instability. There was a consistently high grade of evidence for using a medial clear space (MCS) value of more than 4 to 5 mm to indicate an unstable ankle following SER fracture.

Conclusion:

In conclusion, the results of this systematic review support an MCS value of less than 4 to 5 mm as a good indicator of stability, regardless of choice of stress imaging modality. These patients can be allowed early weightbearing with expected good functional outcomes. Recent published literature favors WB stress radiographs as a reliable and safe technique for assessing stability in SER ankle fractures. However, it should be kept in mind that this is based on studies with relatively low grades of evidence.

Level of Evidence:

Level II, systematic review of variable quality studies.

The Diagnostic Accuracy of Radiographs and Magnetic Resonance Imaging in Predicting Deltoid Ligament Ruptures in Ankle Fractures

BACKGROUND

Operative indications for supination-external rotation (SER) ankle fractures depend on the integrity of the medial structures. Despite the importance of assessing deep deltoid ligament injuries, the accuracy of common diagnostic tests has not been established.

QUESTIONS/PURPOSES

The objective of this study was to compare the ability of injury (non-stress) and stress radiographs and magnetic resonance imaging (MRI) to diagnose deep deltoid ligament ruptures in operative SER ankle fractures.

METHODS

Patients were included who underwent surgical fixation of SER ankle fractures and had appropriate injury and manual stress test radiographs, pre-operative ankle MRI, and intra-operative assessment of deep deltoid integrity by direct visualization. The medial clear space (MCS) was considered positive for all values over 5 mm on the injury or stress mortise radiographs. MRI analysis of the deep deltoid ligament injury was performed by blinded fellowship-trained musculoskeletal radiologists. Intra-operative direct visualization and assessment of the deltoid was performed using a direct medial ankle approach at the time of operative fracture fixation.

RESULTS

Using intra-operative visualization as the gold standard, MCS measurements and MRI had differing abilities to diagnose a deep deltoid rupture. In cases where the MCS was less than 5 mm on injury radiographs and stress tests were performed, MCS measurements were much less accurate than MRI in predicting deltoid ruptures (46% versus 79%, respectively) with a high false positive rate (80%). In contrast, an MCS measurement of greater than 5 mm on injury radiographs was a strong predictor of deep deltoid rupture (accuracy of 95%).

CONCLUSION

Compared with direct visualization of the deltoid ligament intra-operatively, these data support proceeding with surgery when the MCS on injury radiographs is greater than 5 mm without any additional stress tests or advanced imaging. When the MCS is less than 5 mm, we recommend MRI analysis because of its increased accuracy and decreased false positive rate. Improving our ability to diagnose deltoid ruptures will contribute to more effective management of patients with SER ankle fractures.

Weight-bearing in ankle fractures: An audit of UK practice

INTRODUCTION

The purpose of this national study was to audit the weight-bearing practice of orthopaedic services in the National Health Service (NHS) in the treatment of operatively and non-operatively treated ankle fractures.

METHODS

A multicentre prospective two-week audit of all adult ankle fractures was conducted between July 3rd 2017 and July 17th 2017. Fractures were classified using the AO/OTA classification. Fractures fixed with syndesmosis screws or unstable fractures (>1 malleolus fractured or talar shift present) treated conservatively were excluded. No outcome data were collected. In line with NICE (The National Institute for Health and Care Excellence) criteria, "early" weight-bearing was defined as unrestricted weight-bearing on the affected leg within 3 weeks of injury or surgery and "delayed" weight-bearing as unrestricted weight-bearing permitted after 3 weeks.

RESULTS

251 collaborators from 81 NHS hospitals collected data: 531 patients were managed non-operatively and 276 operatively. The mean age was 52.6 years and 50.5 respectively. 81% of non-operatively managed patients were instructed for early weight-bearing as recommended by NICE. In contrast, only 21% of operatively managed patients were instructed for early weight-bearing.

DISCUSSION

The majority of patients with uni-malleolar ankle fractures which are managed non-operatively are treated in accordance with NICE guidance. There is notable variability amongst and within NHS hospitals in the weight-bearing instructions given to patients with operatively managed ankle fractures.

CONCLUSION

This study demonstrates community equipoise and suggests that the randomized study to determine the most effective strategy for postoperative weight-bearing in ankle fractures described in the NICE research recommendation is feasible.

The diagnosis and treatment of isolated type B fibular fractures: Results of a nationwide survey

INTRODUCTION

In isolated Weber B fractures (type B fibular fractures), ruling out instability is critical for safe conservative treatment. In fractures without evident medial injury, additional diagnostics like MRI scan or gravity stress test should be done to differentiate between a stable and unstable fracture. The aim of the current study is to gain more insight in current practice and treatment of type B fractures by Dutch trauma- and orthopaedic surgeons.

MATERIALS & METHODS

In December 2017 and January 2018, 559 trauma surgeons were invited by email to join an online survey. This survey consisted of questions regarding diagnostics and treatment of isolated distal fibula fractures. Also, respondents were asked to state their preferred treatment of eight separate cases.

RESULTS

In total, 161 surgeons participated, covering 68 different hospitals in the Netherlands. Of them, 32.0% treat more than 30 ankle fractures a year. Based on regular mortise radiographs, 13.6% of the respondents chose surgical treatment in case of a medial clear space (MCS) > 4 mm, 33.8% in case of a MCS > 6 mm and 45.5% in case of a MCS > 4 mm in addition to the MCS ≥ superior clear space + 1 mm. Moreover, 18.2% make use of additional diagnostics (43.9% repeat mortise view after a week, 16.6% weight bearing radiograph, 8.6% gravity stress view, 7.9% exorotation radiograph, 6.5% MRI scan, 0.7% ultrasound, 16.8% other) and 8% establishes their decision not based on the mortise radiograph. Fibular dislocation of ≥ 2 mm was used as an indication for surgical treatment by 69%. Of them, 56% decides to treat surgically in these cases, even with proven medial stability.

CONCLUSION

Many surgeons treat type B fibular fractures with a MCS > 4 mm at mortise view surgically, even without proven medial injury. Rarely, additional diagnostics as MRI or gravity stress test are performed in cases with a MCS 4-6 mm. Consequently many stable ankle fractures are treated operatively unnecessarily.

Weight-Bearing Cone-Beam CT Scan Assessment of Stability of Supination External Rotation Ankle Fractures in a Cadaver Model

BACKGROUND

The utility of computed tomography (CT) for measuring medial clear space (MCS) for determination of the stability of supination external rotation (SER) ankle fractures and in comparison to standard radiographs is unknown. We compared MCS on gravity stress (GS) radiographs to GS and weight bearing (WB) cone-beam CT (CBCT).

METHODS

An AO SER 44B3.1 ankle fracture was simulated in 10 human cadavers, also serving as controls. MCS was measured on GS radiographs, GS CBCT, and a simulated WB CBCT scan. Specimens were stable if MCS was <5 mm and unstable if MCS was ≥5 mm. Paired t tests were used to compare MCS from each imaging modality for controls versus SER injuries and stable versus unstable specimens.

RESULTS

Compared with controls assessed by GS radiographs, MCS was greater for an SER injury when assessed by GS radiograph and GS CBCT scan within the stable group. Compared with controls assessed by GS radiographs, MCS was greater for SER injuries when assessed by GS radiograph, GS CBCT scan, and WB CBCT within the unstable group. MCS was reduced for stable versus unstable SER injuries assessed by WB CBCT.

CONCLUSION

In a cadaveric model of SER ankle fracture, the medial clear space was statistically significantly greater for the experimental condition when assessed by gravity stress radiograph and gravity stress CBCT scan. Under weight-bearing conditions, the cone-beam CT scanner distinguished between stable and unstable ankles in the experimental condition.

CLINICAL RELEVANCE

This study suggests that a WB cone-beam CT scan may be able to distinguish between stable and unstable SER ankle fractures and influence operative decision making.

Evaluation and Significance of Mortise Instability in Supination External Rotation Fibula Fractures: A Review Article

Evaluation and management of ankle fractures has progressed in parallel to an evolving understanding of ankle stability. While stability of the mortise had historically been attributed to the lateral malleolus, Lauge-Hansen's contributions followed by multiple other investigations increased the emphasis on the significance of medial-sided injury in destabilizing the mortise. As the importance of the deltoid ligament has been elucidated, the means of assessing ligamentous incompetence and the prognostic significance of an unstable mortise continue to be defined.

LEVEL OF EVIDENCE

Level V, expert opinion.

Stability in ankle fractures: Diagnosis and treatment

Medial column (deltoid ligament) integrity is of key importance when considering the stability of isolated lateral malleolus ankle fractures.Weight-bearing radiographs are the best method of evaluating stability of isolated distal fibula fractures.Computed tomography (CT) scanning is mandatory for the assessment of complex ankle fractures, especially those involving the posterior malleolus.Most isolated trans-syndesmotic fibular fractures (Weber-B, SER, AO 44-B) are stable and can safely be treated non-operatively.Posterior malleolus fractures, regardless of size, should be considered for surgical fixation to restore stability, reduce the need for syndesmosis fixation, and improve contact pressure distribution. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170057.

Role for Primary Repair of Deltoid Ligament Complex in Ankle Fractures

Acute deltoid injuries may occur with ankle fractures. They are often left to heal without repair, possibly leading to chronic medial ankle instability. Stress radiographs identify the need for surgical repair of fractures or soft tissue damage. Gravity stress views have benefits over manually stressing the ankle. MRI can explore the extent of medial soft tissue injuries. Arthroscopy can evaluate and potentially treat deltoid injuries. Interposition of the deltoid may preclude adequate fracture reduction. Except with deltoid tear, fractures should be reduced and fixated, then the deltoid assessed. With persistent instability, primary repair may prevent long-term sequelae.

The additional value of gravity stress radiographs in predicting deep deltoid ligament integrity in supination external rotation ankle fractures

OBJECTIVES

Goal of this study was to investigate whether a gravity stress radiograph is beneficial in determining instability in Supination-External rotation (SER)-type ankle fractures without a medial fracture.

METHODS

39 Patients with a SER-type ankle fracture without a medial or posterior fracture and medial clear space (MCS) < 6 mm at regular mortise view were included. A gravity stress radiograph and Magnetic Resonance imaging (MRI)-scan were made. The MCS measurements of the regular and gravity stress radiographs were compared with the MRI findings (set as reference standard) to determine the sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values as indication for a complete deltoid ligament rupture.

RESULTS

Mean MCS at regular mortise views was 3.11 (range 1.73-5.93) mm, compared to 4.54 (range 2.33-10.40) mm at gravity stress radiographs. With MCS ≥ 4 mm as threshold for predicting a complete rupture at regular ankle mortise views the sensitivity was 66.7, specificity 91.7, PPV 40.0 and NPV 97.0. Gravity stress radiographs with MCS ≥ 6 mm as threshold led to a sensitivity of 100, specificity 91.7, PPV 50.0 and NPV 100.

CONCLUSION

Gravity stress radiographs have more discriminative ability for diagnosing SER-type fractures with or without a complete deltoid ligament tear than regular ankle mortise views.

Weight bearing cone beam CT scan versus gravity stress radiography for analysis of supination external rotation injuries of the ankle

For AO 44-B2 ankle fractures of uncertain stability, the current diagnostic standard is to obtain a gravity stress radiograph, but some have advocated for the use of weight-bearing radiographs. The primary aim was to compare measures of medial clear space (MCS) on weight-bearing cone beam computed tomography (CBCT) scans versus gravity stress radiographs for determining the state of stability of ankle fractures classified as AO SER 44-B2 or Weber B. The secondary aim was to evaluate the details offered by CBCT scans with respect to other findings that may be relevant to patient care. Nine patients were enrolled in this cross-sectional study between April 2016 and February 2017 if they had an AO SER 44-B2 fracture of uncertain stability, had a gravity stress radiograph, and were able to undergo CT scan within seven days. The width of the MCS was measured at the level of the talar dome on all radiographs and at the mid coronal slice on CT. Wilcoxon signed-ranks tests were used to compare MCS between initial radiographs, gravity stress radiographs and weight-bearing CBCT scans. MCS on weight-bearing CBCT scan (1.41±0.41 mm) was significantly less than standard radiographs (3.28±1.63 mm, P=0.004) and gravity stress radiographs (5.82±1.93 mm, P=0.02). There was no statistically significant difference in MCS measured on standard radiographs versus gravity stress radiographs (P=0.11). Detailed review of the multiplanar CT images revealed less than perfect anatomical reduction of the fractures, with residual fibular shortening, posterior displacement, and fracture fragments in the incisura as typical findings. Similar to weight-bearing radiographs, weight-bearing CBCT scan can predict stability of AO 44-B2 ankle fractures by showing restoration of the MCS, and might be used to indicate patients for non-operative treatment. None of the fractures imaged in this study were perfectly reduced however, and further clinical research is necessary to determine if any of the detailed weight-bearing CBCT findings are related to patient outcomes.

When is a simple fracture of the lateral malleolus not so simple? how to assess stability, which ones to fix and the role of the deltoid ligament

Stable fractures of the ankle can be safely treated non-operatively. It is also gradually being recognised that the integrity of the 'medial column' is essential for the stability of the fracture. It is generally thought that bi- and tri-malleolar fractures are unstable, as are pronation external rotation injuries resulting in an isolated high fibular fracture (Weber type-C), where the deltoid ligament is damaged or the medial malleolus fractured. However, how best to identify unstable, isolated, trans-syndesmotic Weber type-B supination external rotation (SER) fractures of the lateral malleolus remains controversial. We provide a rationale as to how to classify SER distal fibular fractures using weight-bearing radiographs, and how this can help guide the management of these common injuries. Cite this article: Bone Joint J 2017;99-B:851-5.

Accuracy and Measurement Error of the Medial Clear Space of the Ankle

BACKGROUND

Measurement of the medial clear space (MCS) is commonly used to assess deltoid ligament competency and mortise stability when managing ankle fractures. Lacking knowledge of the true anatomic width measured, previous studies have been unable to measure accuracy of measurement. The purpose of this study was to determine MCS measurement error and accuracy and any influencing factors.

METHODS

Using 3 normal transtibial ankle cadaver specimens, deltoid and syndesmotic ligaments were transected and the mortise widened and affixed at a width of 6 mm (specimen 1) and 4 mm (specimen 2). The mortise was left intact in specimen 3. Radiographs were obtained of each cadaver at varying degrees of rotation. Radiographs were randomized, and providers measured the MCS using a standardized technique.

RESULTS

Lack of accuracy as well as lack of precision in measurement of the medial clear space compared to a known anatomic value was present for all 3 specimens tested. There were no significant differences in mean delta with regard to level of training for specimens 1 and 2; however, with specimen 3, staff physicians showed increased measurement accuracy compared with trainees.

CONCLUSION

Accuracy and precision of MCS measurements are poor. Provider experience did not appear to influence accuracy and precision of measurements for the displaced mortise.

CLINICAL RELEVANCE

This high degree of measurement error and lack of precision should be considered when deciding treatment options based on MCS measurements.

Dynamic Stress Testing Is Unnecessary for Unimalleolar Supination-External Rotation Ankle Fractures with Minimal Fracture Displacement on Lateral Radiographs

BACKGROUND

This study aimed to identify factors from standard radiographs that contributed to the stability of the ankle mortise in patients with isolated supination-external rotation fractures of the lateral malleolus (OTA/AO 44-B).

METHODS

Non-stress radiographs of the mortise and lateral views, without medial clear space widening or incongruity, were prospectively collected for 286 consecutive patients (mean age, 45 years [range, 16 to 85 years]), including 144 female patients (mean age, 50 years [range, 17 to 85 years]) and 142 male patients (mean age, 40 years [range, 16 to 84 years]) from 2 trauma centers. The radiographs were analyzed for fracture morphology by 2 orthopaedic surgeons, who were blinded to each other's measurements and to the results of external rotation stress radiographs (the reference for stability). Factors significantly associated with ankle mortise stability were tested in multiple logistic regression. Receiver operating characteristic analyses were performed for continuous variables to determine optimal thresholds. A sensitivity of >90% was used as the criterion for an optimal threshold.

RESULTS

According to external rotation stress radiographs, 217 patients (75.9%) had a stable injury, defined as that with a medial clear space of <5 mm. Independent factors that predicted stable ankle mortise were female sex (odds ratio [OR], 2.5 [95% confidence interval (CI), 1.4 to 4.6]), a posterior diastasis of <2 mm (corresponding with a sensitivity of 0.94 and specificity of 0.39) on lateral radiographs (OR, 10.8 [95% CI, 3.7 to 31.5]), and only 2 fracture fragments (OR, 7.3 [95% CI, 2.1 to 26.3]). When the posterior diastasis was <2 mm and only 2 fracture fragments were present, the probability of a stable ankle mortise was 0.98 for 48 female patients (16.8%) and 0.94 for 37 male patients (12.9%).

CONCLUSIONS

Patients with noncomminuted lateral malleolar fractures (85 patients [29.7%]) could be diagnosed with a stable ankle mortise without further stress testing, when the fracture line widths were <2 mm on lateral radiographs.

LEVEL OF EVIDENCE

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