The effect of computerised tomography on operative planning in posterior malleolus ankle fractures

Computed Tomography Scans and Fixation Rates for Trimalleolar Ankle Fractures Over 10 Years at a Level 1 Trauma Center

Background

The posterior malleolus component of the trimalleolar ankle fracture has posed a controversial topic for diagnostic imaging and surgical management. Preoperative computed tomography (CT) scans are used to better appreciate fracture morphology and may affect management techniques. No prior study has investigated the trend in preoperative CT scan use and the rates of posterior and syndesmotic fixation for trimalleolar injuries.

Methods

This retrospective cohort study evaluated the use of preoperative CT scans and the rates of posterior and syndesmotic fixation for trimalleolar ankle fractures over a 10-year period at an adult level 1 trauma center. Patients surgically managed for ankle fractures with OTA/AO classifications of 44B3, 44C3.3, 44C1.3, 44C2.3, and 44A3 were identified and included using Current Procedural Terminology codes and a prospectively collected fracture registry. Demographic information, comorbidities, fixation methods, and use of preoperative CT scan were recorded. Comparative analyses were performed to assess for yearly differences in demographic characteristics along with changes in trends of preoperative CT scans and posterior and syndesmotic fixation.

Results

A total of 1191 patients were included in the analyses. OTA/AO 44B3.2 fractures were the most common injuries (yearly range of 59.4%-80.1%). The rate of posterior fixation did not significantly increase during the study interval (1.4% growth per year [95% CI -0.27, 3.07]). However, the rate of preoperative CT scan use significantly increased by 2.76% (95% CI 1.99, 3.52) per year and the rate of syndesmotic fixation increased by 2.58% (95% CI 1.17, 3.99) per year. Fixation methods for both the syndesmosis and posterior malleolus changed during the study timeline.

Conclusion

Despite a relatively stable rate of posterior fixation, the frequency of preoperative CT scans and use of syndesmotic fixation increased significantly over a 10-year study period.

Level of Evidence

Level IV, descriptive pilot study.

Classifications of posterior malleolar fractures: a systematic literature review

INTRODUCTION

Complex ankle fractures frequently involve the posterior malleolus. Many classifications describing posterior malleolar fractures (PMF) exist. The aim of this study was to provide a systematic literature review to outline existing PMF classifications and estimate their accuracy.

METHODS

The databases PubMed and Scopus were searched without time limits. Only specific PMF classifications were included; general ankle and/or pilon fracture classifications were excluded. Selection and data extraction was performed by three independent observers. The systematic literature search was performed according to the current criteria of Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA). The methodological quality of the included studies was quantified using the modified Coleman score.

RESULTS

A total of 110 studies with a total of 12.614 patients were included. Four main classifications were identified: Those describing the size of the posterior malleolar fracture (n = 66), Haraguchi (n = 44), Bartoníček/Rammelt (n = 21) and Mason (n = 12). The quality of the studies was moderate to good with a median Coleman-score of 43.5 (14-79) and a weighted median Coleman-score of 42.5 points. All classifications achieved a substantial to perfect score regarding the inter- and intraobserver reliability, with Mason scoring the lowest in comparison.

CONCLUSIONS

None of the reviewed PMF classifications has been able to establish itself decisively in the literature. Most of the classifications are insufficient in terms of a derivable treatment algorithm or a prognosis with regard to outcome. However, as the Bartoníček/Rammelt classification has the greatest potential due to its treatment algorithm, its reliability in combination with consistent predictive values, its usage in clinical practice and research appears advisable.

Reduction of Posterior Malleolus Fractures With Open Fixation Compared to Percutaneous Treatment

Background

Operative decision making between approaches to posterior malleolus reduction remains a challenge. The purpose of this study is to compare the quality of reduction between percutaneous and open reduction of posterior malleolus fractures and to identify factors associated with malreduction.

Methods

Operatively managed ankle fractures that included posterior malleolus fixation were reviewed. Fracture characteristics were determined on preoperative CT scans. Initial postoperative radiographs were used to measure reduction of the posterior malleolus articular surface and graded as satisfactory (<2 mm step-off) or malreduced (≥2 mm step-off). Final postoperative PROMIS scores and 1-year complications were compared between percutaneous and open cohorts. A multivariate stepwise regression model was used to evaluate predictors for malreduction.

Results

A total of 120 patients were included. Open reduction was performed in 91 (75.8%) compared with 29 (24.2%) who underwent percutaneous reduction. Malreduction (≥2-mm articular step-off) occurred in 11.7% of patients. Malreduction rates were significantly higher with percutaneous fixation than open fixation (24.1% vs 7.7%, P = .02). Multiple fragments and those with ≥5 mm of displacement demonstrated higher malreduction rates with percutaneous fixation (P < .05 for both), whereas single fragments and those with <5 mm of displacement experienced similar malreduction rates with percutaneous or open fixation. Initial displacement ≥5 mm (relative risk [RR] = 3.8, 95% CI = 1.2-11.5, P = .02) and percutaneous treatment (RR = 4.1, 95% CI = 1.6-10.5, P < .01) were identified as independent risk factors for malreduction. There were no significant differences in 1-year complication rates or final PROMIS scores between groups.

Conclusion

Open reduction of the posterior malleolus may lead to improved fracture reduction compared to percutaneous reduction without significant increase in complications. Open fixation improves reduction among fractures with multiple fragments or ≥5 mm of displacement, whereas fractures with a single fragment or <5 mm of displacement achieve similar reductions regardless of approach. Initial displacement ≥5 mm and percutaneous reduction are independent risk factors for malreduction.

Level of evidence

Level III, therapeutic.

Clinical effects of 3D printing-assisted posterolateral incision in the treatment of ankle fractures involving the posterior malleolus

Objective

To explore the clinical outcomes of a 3D printing-assisted posterolateral approach for the treatment of ankle fractures involving the posterior malleolus.

Methods

A total of 51 patients with ankle fractures involving the posterior malleolus admitted to our hospital from January 2018 to December 2019 were selected. The patients were divided into 3D printing group (28 cases) and control group (23 cases). 3D printing was performed for ankle fractures, followed by printing of a solid model and simulation of the operation on the 3D model. The operation was then performed according to the preoperative plan, including open reduction and internal fixation via the posterolateral approach with the patient in the prone position. Routine x-ray and CT examinations of the ankle joint were performed, and ankle function was evaluated using the American Foot and Ankle Surgery Association (AOFAS) ankle-hindfoot score.

Results

All patients underwent x-ray and CT examinations. All fractures healed clinically, without loss of reduction or failure of internal fixation. Good clinical effects were achieved in both groups of patients. The operation time, intraoperative blood loss and intraoperative fluoroscopy frequency in the 3D printing group were significantly less than those in the control group (p < 0.05). There was no significant difference between the two groups in the anatomical reduction rate of fractures or the incidence of surgical complications (p > 0.05).

Conclusion

The 3D printing-assisted posterolateral approach is effective in the treatment of ankle fractures involving the posterior malleolus. The approach can be well planned before the operation, is simple to perform, yields good fracture reduction and fixation, and has good prospects for clinical application.

Can Lateral X-Rays Reliably Determine Which Posterior Malleolus Ankle Fractures Need a CT?

BACKGROUND

For rotational ankle fractures with a posterior malleolus fracture (PMF), the decision to further evaluate the ankle injury with computed tomography (CT) is challenging. The objective of this study is to determine how well PMF fracture size on x-rays correlates with size on CT, and how well x-rays can predict which patients receive PMF fixation after CT review.

METHODS

This is a retrospective study of adult ankle fractures with PMFs that had preoperative radiographs and CT imaging over a 5-year period. PMF x-ray and CT measurements were recorded, and relationships between x-ray measurements and final PMF fixation plan after CT review were evaluated.

RESULTS

A total of 98 patients were identified with both x-rays and preoperative CT imaging. Pearson's rank correlation demonstrated a strong relation between PMF width percentage measured on x-ray and CT (r = 0.724). Of the 45 patients with a PMF size under 20% on x-ray, only one patient (with an apparent incarcerated fragment) underwent PMF fixation after review of the CT.

CONCLUSIONS

PMF width on lateral x-ray correlates well with CT size and is sensitive for predicting the need for dedicated posterior malleolus based on one institutional practice pattern. Below 20% fracture width on lateral x-ray, a dedicated CT rarely leads to a decision to perform PMF fixation. Limiting pre-operative CT to those with PMF width >20% could reduce CT utilization by as much as 45% without negatively affecting patient care.

LEVELS OF EVIDENCE

Level III: Diagnostic.

Prognostic value of the Haraguchi classification in posterior malleolar fractures in A0 44-C type ankle fractures

BACKGROUND AND PURPOSE

Incidence of posterior malleolar fractures (PMFs) associated with ankle fractures is historically based on plain radiographs. Several classification systems for PMF are currently in use, but the reliability of the Haraguchi classification is not reported. The aim of this diagnostic cohort study was to assess incidence of PMF in patients with AO 44-C fractures, and test the reliability of the Haraguchi fracture classification based on CT. In addition, to evaluate the clinical outcome in patients with PMF.

METHODS

210 patients with an AO 44-C type fracture treated with syndesmotic fixation between 2011 and 2017 were included. Presence of PMF was registered, morphology was assessed and classified according to the Haraguchi classification. Interobserver agreement for the Haraguchi classification was evaluated. Patient assessment was conducted at 6 weeks, 6 months, 1 and 2 years. The American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Score (AOFAS) was the primary outcome measure. Secondary outcome measures included presence of osteoarthritis.

RESULTS

125 of 210 patients (60%) had a PMF. 34% of the PMFs were missed on plain radiographs compared to CT. The interobserver agreement was 0.797, (95% CI: 0.705 to 0.889, p < 0.001), for the Haraguchi classification. The 2-year follow-up rate was 86%. Haraguchi type II fractures had a lower AOFAS compared with the no-fracture group at 6 weeks (mean difference -7.5 (95% CI; -15.0 to -0.2), p = 0.04) and 6 months (mean difference -8.4 (95% CI; -15.3 to -1.5), p = 0.01). Presence of osteoarthritis was higher in patients with Haraguchi type II PMF compared to the no PMF group, this finding was not significant (relative risk (RR) 1.6(95% CI 1.1 to 2.4, p = 0.059)).

CONCLUSIONS

Plain radiographs underestimated PMF. Patients with a Haraguchi type II fracture had a poorer outcome measured by the AOFAS score compared to no PMF up until 6 months. Classification of PMF according to the Haraguchi classification was reliable.

Ankle CT scan allows better management of posterior malleolus fractures than X-rays

PURPOSE

Undiagnosed and undertreated posterior malleolus fractures lead to early ankle instability and arthritis. A preoperative CT scan could improve the management of those fractures. This study assessed the benefits of a systematic ankle CT scanner to diagnose and manage posterior malleolus fracture.

METHODS

A monocentric retrospective cohort study was conducted. Sixty consecutive patients with bimalleolar fractures were operated and underwent a preoperative CT scan. The mean age was 50.0 years old (18.6 years old) with a mean body mass index of 20.3 (kg/m²) (11.4 kg/m²) and 71.7% (43/60) of women. The primary outcome was the rate of posterior malleolus fragment diagnosed on X-rays and on CT scan. Secondly, interobserver and interobserver's agreement were compared between conventional X-rays and CT scan.

RESULTS

Thirty-five (58.3%) posterior fragment fractures were observed on X-rays and 53 (88.3%) on the preoperative CT scan (p < 0.01). The intraobserver reproducibility for X-rays was low (0.02 [- 0.23; 0.27]) and moderate for CT scan (0.45 [0.0; 0.84]). The interobserver reproducibility for X-rays was moderate (0.39 [0.15; 0.60]) and excellent for CT scan (0.78 [0.0; 1.0]).

CONCLUSION

A wide proportion of bimalleolar fractures are associated with posterior malleolus fractures and undiagnosed with standard X-rays. We advocate a systematic preoperative CT scan in the management of bimalleolar fractures.

LEVEL OF EVIDENCE

Level IV, retrospective cohort study.

TRIAL REGISTRATION NUMBER

2218999v0, date of registration: 11/08/2020 (retrospectively registered).