Diagnostic Accuracy of 2-Dimensional Computed Tomography for Articular Involvement and Fracture Pattern of Posterior Malleolar Fractures

Frequent Sural Nerve Injury with Posterior Approach for Ankle Fracture Fixation

INTRODUCTION

The purpose of this study was to report the incidence of iatrogenic sural nerve injury in a large, consecutive sample of surgically managed ankle fractures and to identify factors associated with sural nerve injury and subsequent recovery. We hypothesize that a direct posterior approach may be associated with higher risk of iatrogenic sural nerve injury.

METHODS

A retrospective cohort study of 265 skeletally mature patients who sustained ankle fractures over a 2-year period was done. All were treated with open reduction and internal fixation of fractured malleoli. Patient, injury, and treatment features were documented. The presence (n = 26, 9.8%) of sural nerve injury and recovery of sural nerve function were noted.

RESULTS

All 26 sural nerve injuries were iatrogenic, occurring postoperatively after open reduction and internal fixation. Patients who sustained sural nerve injuries had more ankle fractures secondary to motor vehicle collisions (23.1% versus 9.2%), more associated trimalleolar fractures (69.2% versus 33.9%), and more Orthopaedic Trauma Association/AO 44B3 fractures (57.7% versus 25.1%), all P < 0.05. A posterior approach to the posterior malleolus through the prone position was used in 20.4% of patients. All 26 of the sural nerve injuries (100%) occurred when the patient was placed prone for a posterior approach, P < 0.001. Therefore, 26 of the 54 patients (48%) treated with a posterior approach sustained an iatrogenic sural nerve injury. 62% of patients had full recovery of sural nerve function with no residual numbness, and patients with nerve recovery had fewer associated fracture-dislocations (23.1% versus 100%, P = 0.003).

CONCLUSIONS

A posterior approach for posterior malleolus fixation was associated with a 48% iatrogenic sural nerve injury rate, with 62% recovering full function within 6 months of injury. Morbidity of this approach should be considered, and surgeons should be cautious with nerve handling.

LEVEL OF EVIDENCE

Level III, Therapeutic.

Historic indications for fixation of posterior malleolus fractures- where did they come from and where are we now?

INTRODUCTION

The indications for reduction and fixation of the posterior malleolus component of rotational ankle fractures have been controversial for nearly a century. This study aims to identify the historical basis for surgical intervention and trace trends in management strategies over time.

METHODS

In March 2023, a systematic review of full-text, English-language articles providing indications for surgical fixation of the posterior malleolus component of rotational ankle fractures was performed. Articles underwent title and abstract screening before undergoing full-text review.

RESULTS

Historical indications for surgical fixation were size-dependent, with fractures comprising 25 % to 33 % of the plafond recommended for internal fixation. Modern studies suggest that nonoperative management of posterior malleolus fractures below this threshold results in residual malreduction of the articular surface, syndesmotic instability, and an increased need for independent fixation of the syndesmosis.

CONCLUSIONS

Size-based indications for posterior malleolus fracture fixation are based on Level V evidence from small retrospective case series published nearly one century ago and should be retired. While the size of the posterior malleolus component cannot be ignored, additional factors like fracture morphology and location within the plafond should guide modern surgical indications. Contemporary studies indicate that reduction and fixation of small posterior malleolus fractures (comprising less than 25 % of the articular surface) are associated with improved articular reductions, tibiotalar contact pressures, syndesmotic stability with decreased need for independent fixation of the syndesmosis, and superior postoperative outcomes.

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.

Methods for Biomechanical Testing of Posterior Malleolar Fractures in Ankle Fractures: A Scoping Review

BACKGROUND

The treatment of posterior malleolar fractures (PMFs) is debated, including the need for surgery and method of fixation. Recent literature has suggested that fracture pattern, rather than fragment size, may be an important predictor for ankle biomechanics and functional outcome. Biomechanical studies have been conducted to provide evidence-based treatment on the effects of fracture and fixation on contact pressure and stability. The objective of this scoping review is to summarize the methodologies used in biomechanical studies on PMFs and assess whether they are sufficient to test the need for surgery and method of fixation.

METHODS

A scoping review of publications before January 2022 was performed. PubMed/Medline and Embase Ovid were searched for cadaver or finite element analysis (FEA) studies that created and tested the effects of PMFs in ankle fractures. Both cadaver and FEA studies were included. Data about fragment characteristics, mode of testing, and outcomes were charted by 2 persons from the study group. The data were synthesized when possible and compared.

RESULTS

We included 25 biomechanical studies, including 19 cadaver studies, 5 FEA studies, and 1 cadaver and FEA study. Aside from the fragment size, few other fragment characteristics were reported. Mode of testing varied with different loads and foot positions. Strong conclusions on the effects of fracture and fixation on contact pressure and stability could not be made.

CONCLUSION

Biomechanical studies on PMFs demonstrate wide variability in fragment characteristics and mode of testing, which makes it difficult to compare studies and draw conclusions on the need for surgery and method of fixation. Additionally, limited reporting of fragment measurements questions the applicability to clinical practice. The biomechanical literature on PMFs would benefit from the use of a standard classification and universal fragment measurements to match clinical injuries in future biomechanical studies. Based on this review, we recommend the Mason classification, which addresses the pathomechanism, and use of the following fragment measurements in all 3 anatomic planes when creating and describing PMFs: fragment length ratio, axial angle, sagittal angle or fragment height, and interfragmentary angle. The testing protocol needs to reflect the purpose of the study.

CLINICAL RELEVANCE

This scoping review demonstrates wide methodological diversity of biomechanical studies. Consistency in methodology should enable comparison of study results, leading to stronger evidence-based recommendations to guide surgeons in decision making and offer PMF patients the best treatment.

Identifying the Potential Role of Regional Bone Mineral Density on the Degree of Malleolar Involvement in Acute Ankle Fractures

Ankle fractures are a common traumatic lower extremity injury and are generally classified and characterized by the rotational mechanism of injury. At each malleolus (i.e., posterior, medial, and lateral) a fracture can occur or a ligamentous injury may be sustained. The purpose of this retrospective study was to determine if bone mineral density is a contributing factor on the number of fractured malleoli versus soft tissue injury in adult ankle fractures. Data was obtained from a registry of ankle fractures that were operatively treated by the foot and ankle team throughout our institutional facilities, from July 2017 to August 2019, and in which a preoperative computerized tomography scan was performed. Regional bone mineral density (BMD) was measured by calculating the average Hounsfield Unit (HU) on axial computerized tomography images of the distal fibula and tibia. The average HU was then compared to the number of fractured malleoli. One hundred eight patients met the study criteria. We identified statistically significant relationships between decreased BMD with increasing age (p < .01) and the male gender (p < .01). After adjusting for the covariates age and gender, no statistically significant relationship was identified between BMD and the number of malleoli involved in a given ankle fracture (p = .11). These findings suggest that while more investigation is required for ankle fracture patterns and BMD evaluation, increased age and biologic female gender is significantly related to decreased BMD as identified via HU.

Validation of three classification systems for posterior malleolus fractures of the ankle

PURPOSE

A number of classification systems exist for posterior malleolar ankle fractures. The user reliability of these classification systems remains unclear. The primary aim of this study was to evaluate the reliability of three commonly utilised classification systems for fractures of the posterior malleolus.

METHODS

Imaging of 60 patients across 2 hospitals with ankle fractures including a posterior malleolar fragment was identified. All patients had undergone plain radiographs and computed tomography of their injured ankle as part of their normal standard of care. 9 surgeons including pre-resident/registrar level, resident/registrar level, and attending/consultant level applied the Haraguchi, Bartoníček, and Mason classifications to these fractures, at two timepoints, at least 4 weeks apart. The order was randomised between assessments. Inter-rater reliability was assessed using Fleiss' κ and standard error (SE). Intra-rater reliability was assessed using Cohen's κ and standard error (SE).

RESULTS

Inter-rater reliability (Fleiss' κ) was calculated for the Haraguchi classification as 0.588 (SE 0.023), for the Bartoníček classification as 0.626 (SE 0.019), and the Mason classification as 0.541 (SE 0.098). Intra-rater reliability (Cohen's κ) was 0.761 (SE 0.098) for the Haraguchi classification, 0.761 (SE 0.091) for the Bartoníček, classification, and 0.724 (SE 0.096) for the Mason classification.

CONCLUSIONS

This study reports the inter-rater and intra-rater reliability for three classification systems for posterior malleolus fractures. Based on definitions by Landis and Koch (Biometrics 33:159-174, 1977), inter-rater reliability was rated as 'moderate' for the Haraguchi and Mason classifications and 'substantial' for the Bartoníček classification. Similarly, the intra-rater reliability was rated as 'substantial' for all three classifications.

Variation in posterior fragment fixation in the Netherlands: a nationwide study

PURPOSE

The treatment of the posterior fragment in trimalleolar fractures differs from hospital to hospital in the Netherlands. A nationwide survey was performed to evaluate the fixation criteria and practice variation.

METHODS

An online cross-sectional survey amongst (orthopaedic) trauma surgeons was performed in the Netherlands. It consisted of three sections: a general section, a section showing preoperative images of six cases and a section with postoperative images of nine cases.

RESULTS

A total of 151 surgeons completed the online survey. 45% of the respondents indicated that they fixated the posterior fragment if smaller than 25% of the intra-articular surface. 48% preferred an open posterior approach to fixate the posterior fragment. There was good consensus in treatment for the two cases with Bartonicek type 4 fractures (operative treatment in 73 and 72% respectively). Little consensus was found for Bartonicek type 2 and 3 fractures (88% opted for operative treatment in one case, but 89% for conservative treatment in the second case). Reoperation was mostly considered in cases with a step-off of more than 1 mm (by 33-38% of the respondents). There was great variation in the choice of treatment if only the size of the posterior fragment was considered. Other fixation criteria such as postoperative step-off or instability after fixation of the lateral and medial malleoli are taken into account. In cases where fixation was needed, a percutaneous approach and an open posterolateral approach were equally preferred.

CONCLUSIONS

There is much variation in treatment of the posterior malleolar fracture amongst orthopaedic and trauma surgeons in the Netherlands. The percutaneous approach and open posterolateral approach to fixate the posterior malleolar fracture seem to be equally used in the Netherlands. Still, there is no uniformity in treatment of posterior malleolar fracture, especially for Bartonicek 2 and Bartonicek 3 fractures. Reoperation is considered by less than half of the surgeons in case of postoperative persistent step-off of more than 1 mm.

The Intercalary Fragment in Posterior Malleolus Fractures: Characterization and Significance

Methods of fixation in ankle fractures involving the posterior malleolus have become increasingly scrutinized. With the increase in computed tomography (CT), an intercalary fracture fragment (ICF) adjacent to the posterior malleolus has been oft described. Treatment of the ICF remains controversial and the purpose of this study was to evaluate radiographic and clinical outcomes in patients who had direct reduction and fixation of this fragment compared to those where the ICF was not fixed. This retrospective study included 249 trimalleolar and posterior pilon ankle fractures grouped into those who had the ICF reduced and fixed (n = 74) and those where the ICF was not directly addressed (n = 175). CT scans were evaluated for size and location of the ICF. Demographic, radiographic and intraoperative variables were collected and analyzed. The group which had the ICF reduced and fixed had decreased Kellgren-Lawrence scores (p = .001). There was also a higher rate of repeat surgery in the group who had the ICF fixed, although not meeting statistical significance. There were no differences in size or location of the ICF fragment between groups. We did identify similarities with other studies in regard to size and posterolateral location of the ICF between groups. However, based on worsening radiographic outcomes of the group where the ICF was reduced and fixed, we do not necessarily recommend universal treatment of this fragment. The surgeon's goal should always be a concentric articular reduction and treatment of the ICF should be considered on a case-by-case basis.

Can we predict size, Haraguchi type and preoperative displacement of posterior malleolar fractures in association with tibial shaft fractures?

PURPOSE

To (1) determine if any injury characteristics or radiographic parameters of tibial shaft fractures (TSFs) could predict posterior malleolar fracture (PMF) size, and (2) identify characteristics of PMFs that were fixed versus those that were not in a cohort of ipsilateral TSFs that underwent intramedullary nailing.

METHODS

A cross-sectional radiographic study was performed at a single academic institution. Demographic and radiographic parameters of TSFs were recorded, including fracture obliquity angle (FOA) and distance from distal extent of fracture to plafond (DFP). Using CT, the PMFs were evaluated for Haraguchi classification, size measurements, and preoperative displacement. Multivariate regression analysis was used to identify independent predictors of PMF Harachuchi classification, size parameters, and preoperative displacement. Univariate differences between PMF that were fixed and not fixed were identified.

RESULTS

47 (50%) PMF underwent surgical fixation with 47 treated conservatively. There were no demographic differences between groups. Multivariate linear regression demonstrated increasing DFP and high energy injury mechanism as independent variables correlated with plafond surface area involvement, PMF height and width on sagittal CT cuts. Increasing DFP alone was correlated with PMF width on axial CT cuts and extent > 50% into incisura. Haraguchi type II fractures were associated with high energy injury mechanism (OR = 4.2 [95% CI = 1.3-14.5]; p = 0.02). Odds of Haraguchi type 3 fractures increased 9% per increased year of age (OR = 1.09 [95% CI = 1.04-1.16]; p = 0.006) and decreased 13% per 1% increase in relative DFP (OR = 0.87 [95% CI = 0.75-0.98]; p = 0.04).

CONCLUSIONS

An increasing DFP of TSFs and high energy injury mechanism were independent predictors of PMF size, and high energy injury mechanism was also correlated with Haraguchi type II fracture patterns. Increasing age and decreasing DFP of TSFs predict Haraguchi type III PMF patterns. These radiographic parameters should prompt surgeons to plan for fixation in scenarios in which CT scan is not available.

LEVEL OF EVIDENCE

Diagnostic Level III.

[Established classification systems of posterior malleolar fractures : A systematic literature review]

BACKGROUND

Posterior malleolar fractures are found in almost 50% of all ankle fractures. The high clinical relevance of these joint fractures is explained by the significantly worse clinical and functional outcome. There is still a lack of unified opinion regarding the classification and treatment of these fractures.

OBJECTIVE

The aim of this article is to provide a systematic literature review of clinical studies that investigated posterior malleolar fractures and classified them using one of the three established classifications according to Haraguchi, Bartonicek/Rammelt, or Mason.

MATERIAL AND METHODS

PubMed was searched without time limits. 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 27 studies with a total of 2220 patients were included in this systematic literature review. Trimalleolar fractures showed a significantly less favorable prognosis than other ankle fractures. The quality of reduction was the most important prognostic factor for the clinical outcome.

CONCLUSION

None of the three classifications examined has become established in the literature. Most of the classifications are weak or should not be used with respect to a derivable treatment algorithm or a prognosis with respect to the outcome. Only the classification according to Bartonicek/Rammelt is suitable to become established in the literature and in clinical practice due to its derivable treatment algorithm.

The influence of size and comminution of the posterior malleolus fragment on gait in trimalleolar ankle fractures

BACKGROUND

Ankle fractures involving the posterior malleolus generally lead to worse outcome. However, no studies on gait in trimalleolar ankle fractures have evaluated the influence of size and comminution of the posterior malleolar fragment.

METHODS

We expected patients with more severely comminuted posterior malleolus, more severe fracture type and larger posterior fragment to have reduced gait kinematics and poorer patient-reported outcomes. 26 trimalleolar ankle fracture patients were compared with 14 healthy controls and kinematically analyzed using the Oxford Foot Model. Functional outcome was based on 4 patient reported outcome questionnaires. Effects of posterior fragment size, comminution and Haraguchi fracture classification were determined on conventional and 3D CT-scans.

FINDINGS

Trimalleolar patients had lower walking speed and reduced range of motion between the hindfoot and tibia in both loading and push-off phases in the sagittal and transverse planes. The range between the hindfoot and tibia in the sagittal plane in the push-off phase correlated significantly with patient reported outcomes. The absolute and relative surface area of the posterior fragment on conventional CT-scans and 3D CT-scans, correlated significantly with range of motion. Patients with a posterior malleolus size >10% of the posterior malleolus had lower flexion-extension between forefoot and hindfoot during loading phase than patients with a size ≤10%.

INTERPRETATION

Trimalleolar fractures reduce walking speed and range of motion in the talocrural joint. Reduced range in the talocrural joint is associated with poorer outcomes. Posterior fragment size correlated significantly with range of motion in talocrural and midfoot joints and with patient reported outcomes.

LEVEL OF EVIDENCE

Level 3, retrospective study.

Can treatment of posterior malleolus fractures with tibio-fibular instability be usefully addressed by Bartonicek classification?

INTRODUCTION

Ankle fractures account for 4% of all fractures and treatment of those involving the Posterior Malleolus remains controversial. Clinical and radiological outcomes in a cohort of patients with Posterior Malleolus fractures conservatively treated were retrospectively evaluated; furthermore, a treatment algorithm was suggested.

METHODS

Patients were divided according to Bartoníček classification. The clinical evaluation was made with OMAS/AOFAS scores; the radiological evaluation with Van Dijk classification for post-traumatic arthritis.

RESULTS

Clinical outcome worsened with the severity of Bartoníček classification, but early degenerative changes were not correlated neither to the clinical outcome nor to the injury pattern. Clinical and radiological outcomes depended on the damage of the syndesmosis as articular step-offs and tibio-fibular notch involvement.

DISCUSSION

We recommend conservative treatment for Bartoníček type I, type II and type III fractures, the latter when undisplaced and without tibial plafond depression. We suggest surgical treatment for type IV and displaced type III fractures.

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).

Percutaneous posteroanterior screw fixation for Haraguchi type 1 posterior malleolar fracture in tri-malleolar fracture: Operative technique and randomized clinical results

PURPOSE

The study described a novel surgical treatment of Haraguchi type 1 posterior malleolar fracture in tri-malleolar fracture and patient outcomes at intermediate period follow-up.

METHODS

All patients from January 2015 to December 2017 with tri-malleolar fracture of which posterior malleolar fractures were Haraguchi type 1, were surgically treated in this prospective study. Lateral and medial malleolar fractures were managed by open reduction and internal fixation through dual incision approaches. 36 cases of Haraguchi type 1 posterior malleolar fractures were randomly performed by percutaneous posteroanterior screw fixation with the aid of medial exposure (group 1). And 40 cases were performed by percutaneous anteroposterior screw fixation (group 2). Clinical outcomes, radiographic outcomes and patient-reported outcomes were recorded.

RESULTS

Seventy-six patients with mean follow-up of 30 months were included. There were no significant differences in the mean operation time (81.0 ± 11.3 vs. 77.2 ± 12.4), ankle function at different periods of follow-up, range of motions and visual analog scale (VAS) at 24 months between the two groups (p > 0.05). However, the rate of severe post-traumatic arthritis (Grade 2 and 3) and the rate of step-off rather than gap in radiological evaluation were lower in group 1 than that in group 2 (p < 0.05).

CONCLUSION

Using our surgical technique, more patients had good outcome with a lower rate of severe post-traumatic arthritis, compared with the group of percutaneous anteroposterior screw fixation. Percutaneous posteroanterior screw fixation can be a convenient and reliable alternative in treating Haraguchi type 1 posterior malleolar fracture.

Traditional Approach vs Posterior Approach for Ankle Fractures Involving the Posterior Malleolus

BACKGROUND

In the past, posterior malleolus fragments (PMFs) commonly have been indirectly reduced and fixed when fragments involve 25% or more of the tibial articular surface, while smaller fragments were left unfixed. The posterior approach has become increasingly popular and allows fixation of even smaller fragments. This study compares clinical outcome for the 2 treatment strategies.

METHODS

Patients with ankle fractures involving a PMF treated from 2014 to 2016 were eligible for inclusion. Patients were allocated to group A (treated with a posterior approach) or group B (treated with the traditional approach) according to the treatment given. A one-to-one matching of patients from each group based on the size of the PMF was performed. Patient charts were reviewed, and outcome evaluation was performed clinically, radiographically, and by patient-reported outcome measures (PROMs; Self-Reported Foot and Ankle Score, RAND-36, visual analog scale [VAS] of pain, and VAS of satisfaction). Forty-three patients from each group were matched. Median follow-up was 26 (interquartile range [IQR], 19-35) months postoperatively.

RESULTS

The median PMF size was 17% (IQR, 12-24) in both groups, and they reported similar results in terms of PROMs. Fixation of the PMF was performed in 42 of 43 (98%) patients in group A and 7 of 43 (16%) patients in group B (P < .001). The former group more frequently got temporary external fixation (56% vs 12%, P < .01) and less frequently had syndesmotic fixation (14% vs 49%, P < .01), and they had less mechanical irritation and hardware removal but more noninfectious skin problems (28% vs 5%, P < .01). Median time from injury to definitive surgery (8 vs 0 days, P < .001) and median length of stay (12 vs 3 days, P < .001) were longer in group A.

CONCLUSION

Comparison of treatment strategies for ankle fractures involving the posterior malleolus showed similar results between patients treated with a traditional approach and a posterior approach.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Clinical and radiological mid- to long-term results after direct fixation of posterior malleolar fractures through a posterolateral approach

BACKGROUND

Direct fixation of posterior malleolar fractures has been shown to lead to higher accuracy of fracture reduction compared to an indirect anterior to posterior fixation but lacks long-term clinical results. This study shows the mid- to long-term clinical and radiological outcome after direct fixation of the posterior malleolus through a posterolateral approach.

MATERIALS AND METHODS

Thirty-six patients with an ankle fracture including a posterior malleolar fragment (23 × AO-44C, 12 × AO-44B, 1 × unclassifiable) treated with direct fixation of the fragment through a posterolateral approach were retrospectively evaluated. There were 24 females (67%) with a mean age of 63 (range 34-80) years and a BMI of 28 (range 19-41) kg/m² at the time of surgery. An initial fracture-dislocation was seen in 67%. The clinical outcome was assessed with the Visual Analog Scale (VAS, 0-10 points) and the American Foot and Ankle Society (AOFAS, 0-100 points) score. Posttraumatic osteoarthritis was recorded with the Van Dijk Classification (grade 0-III). Subgroup analyses of patient- and fracture-associated risk factors (age, BMI, smoking, fracture-dislocation, postoperative articular step-off) were assessed to reveal possible negative prognostic predictors.

RESULTS

After a mean follow-up of 7.9 (range 3-12) years, the median VAS was 1 (IQR 0-2) point, and the median AOFAS score was 96 (IQR 88-100) points. Ankle range of motion measurements showed a significant, but clinically irrelevant, difference in plantar- and dorsiflexion between the affected and unaffected ankle. 92% of the patients were very satisfied or satisfied with the postoperative course. 89% had no preoperative signs of ankle osteoarthritis. Osteoarthritis progression was seen in 72%, with 50% showing grade II or III osteoarthritis at the final follow-up. No significant negative prognostic factors for a worse clinical outcome could be detected.

CONCLUSION

Direct fixation of posterior malleolar fractures through a posterolateral approach showed good clinical mid- to long-term results with a high satisfaction rate but substantial development of posttraumatic ankle osteoarthritis. Further studies should include CT analysis of the preoperative fracture morphology and even, perhaps, the postoperative reduction accuracy to evaluate the benefit of posterior malleolar fracture reduction in preventing ankle osteoarthritis in the long term.

LEVEL OF EVIDENCE

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

Comparison of radiographs and CT features between posterior Pilon fracture and posterior malleolus fracture: a retrospective cohort study

OBJECTIVES

This study explored the morphological differences between posterior Pilon fracture and posterior malleolus fracture from radiographs and CT to provide detail for diagnosis and treatment of them.

METHODS

Radiographs and CT imaging data of 174 patients with distal posterior tibial fractures who were treated from January 2013 to January 2019 were retrospectively analyzed. Based on the operation and imaging examination, the fractures were classified into posterior Pilon fractures and posterior malleolus fractures. Radiographic parameters including the width, height, depth, α angle, β angle, γ angle, fragment area ratio 1 (FAR1), δ angle and fragment area ratio 2 (FAR2) of ankle mortise were measured.

RESULTS

There were 96 posterior Pilon fractures (Type I: 30, Type II: 22 and Type III: 44) and 78 posterior malleolus fractures (Type I: 40 and Type II: 38). The ankle depth, α angle, γ angle, FAR1 and FAR2 of posterior Pilon fractures were larger than these of posterior malleolus fractures (p < 0.05). In addition, FAR1 and FAR2 of Type II and Type III posterior Pilon fractures were significantly larger than these of Type I (p < 0.05). FAR1 and FAR2 of Type I posterior malleolus fractures were significantly smaller than these of Type II (p < 0.05).

CONCLUSION

Radiographs combined with CT analysis is an effective method to accurately distinguish morphological features between posterior Pilon fracture and posterior malleolus fracture.

ADVANCES IN KNOWLEDGE

Radiographs combined with CT distinguished the fracture of posterior malleolus and posterior Pilon rapidly and accurately, instead of operation.

Quantification of Postoperative Posterior Malleolar Fragment Reduction Using 3-Dimensional Computed Tomography (Q3DCT) Determines Outcome in a Prospective Pilot Study of Patients With Rotational Type Ankle Fractures

OBJECTIVE

To correlate Q3DCT measurements of residual step-off, gap, and 3D multidirectional displacement of postoperative posterior malleolar fracture fragment reduction in patients with rotational type ankle fractures, with patients' clinical outcome using standardized patient- and physician-based outcome measures.

DESIGN

Prospective cohort study.

SETTING

Level-I Trauma Center.

PATIENTS

Thirty-one patients with ankle fractures including a posterior malleolar fracture (OTA/AO type 44) were included.

INTERVENTION

All patients underwent open reduction internal fixation of their ankle fracture, of which 18 patients (58%) had direct fixation of the posterior malleolar fragment. Decision of (direct) fixation of the posterior malleolar fragment was not standardized and guided by surgeons' preference.

MAIN OUTCOME MEASUREMENTS

Quality of postoperative reduction was quantified using Q3DCT: posterior fragment size (% of joint surface), residual step-off (mm), postoperative gaps (mm), and overall multidirectional displacement were quantified. Foot and Ankle Outcome Score pain and symptoms subscales and quality of life (Short Form-36) at 1 year postoperatively were included as the main outcome measures.

RESULTS

Step-off (mean 0.6 mm, range 0.0-2.7, SD 0.8) showed a significant correlation with worse Foot and Ankle Outcome Score pain and symptoms subscales. Residual fracture gap (mean 12.6 mm, range 0.0-68.8, SD 19.5) and 3D multidirectional displacement (mean 0.96 mm, range 0.0-2.8, SD 0.8) showed no correlation.

CONCLUSIONS

In patients with rotational type ankle fractures involving a posterior malleolar fracture, contemporary Q3DCT measurements of posterior fragment size and residual intra-articular step-off-but not gap-show significant correlation with patient-reported pain and symptoms.

LEVEL OF EVIDENCE

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

Posterior malleolar fracture morphology determines outcome in rotational type ankle fractures

INTRODUCTION

Rotational type ankle fractures with a concomitant fracture of the posterior malleolus are associated with a poorer clinical outcome as compared to ankle fractures without. However, clinical implications of posterior malleolar (PM) fracture morphology and pattern have yet to be established. Many studies on this subject report on fragment size, rather than fracture morphology based on computed tomography (CT). The overall purpose of the current study was to elucidate the correlation of PM fracture morphology and functional outcome, assessed with CT imaging and not with -unreliable- plain radiographs.

METHODS

Between January 2010 and May 2014, 194 patients with an operatively (ORIF) treated ankle fracture, were prospectively included in the randomized clinical EF3X-trial at our Level-I trauma center. The current study retrospectively included 73 patients with rotational type ankle fractures and concomitant fractures of the posterior malleolus. According to the CT-based Haraguchi fracture morphology, all patients were divided into three groups: 20 Type I (large posterolateral-oblique), 21 Type II (transverse medial-extension) and 32 Type III (small-shell fragment). At 12 weeks, 1 year and 2 years postoperatively the Foot and Ankle Outcome Scores (FAOS) and SF-36 scores were obtained, with the FAOS domain scores at two years postoperative as primary study outcome. Statistical analysis included a multivariate regression and secondary a mixed model analysis.

RESULTS

Haraguchi Type II PM ankle fractures demonstrated significantly poorer outcome scores at two years follow-up compared to Haraguchi Types I and III. Mean FAOS domain scores at two years follow-up showed to be significantly worse in Haraguchi Type II as compared to Type III, respectively: Symptoms 48.2 versus 61.7 (p = 0.03), Pain 58.5 versus 84.4 (p < 0.01), Activities of Daily Living (ADL) 64.1 versus 90.5 (p < 0.01).

CONCLUSION

Posterior malleolar ankle fractures with medial extension of the fracture line (i.e. Haraguchi Type II) are associated with significantly poorer functional outcomes. The current dogma to fix PM fractures that involve at least 25-33% of the tibial plafond may be challenged, as posterior malleolar fracture pattern and morphology - rather than fragment size - seem to determine outcome.

CT Analysis of the Posteromedial Fragment of the Posterior Malleolar Fracture

BACKGROUND

To date, there have been no studies describing the characteristics of posteromedial fragment in the posterior malleolus fracture. The aim was to investigate the variability of posteromedial fracture fragments to enable better surgical planning.

METHODS

All Mason and Molloy type 2B fractures, defined as fracture of both the posterolateral and the posteromedial fragments of the posterior malleolus, from our database were identified to analyze the preoperative computed tomography scan. The posteromedial fragment was investigated in 47 cases (mean age, 46.6 years; 11 male, 36 female).

RESULTS

Morphologically, the fracture could be divided into 2 subtypes: (1) a large pilon intra-articular fragment (mean of X axis: 33.0 mm, Y: 30.7 mm, Z: 31.7 mm) presented in 29 cases with mean interfragmentary angle of 32.1 and back of tibia angle of 32.7 degrees (this was seen in 25 of 27 cases with supination injury pattern); and (2) a small extra-articular avulsion fragment (mean of X axis: 9.6 mm, Y: 13.2 mm, Z: 11.5 mm) present in 18 cases with a mean interfragmentary angle of 11.0 and back of tibia angle of 10.1 degrees. It was seen in 80% of pronation injuries.

CONCLUSION

The avulsion type of the posteromedial fragment of posterior malleolus fracture was more common in pronation injuries, likely the result of traction by the intermalleolar ligament, and the pilon type was more common in supination injuries, likely the result of the rotating talus impaction. Because of the intra-articular involvement, we believe the pilon type should undergo fixation to achieve articular congruity, unlike the avulsion type which may only function as a secondary syndesmotic stabilizer.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Operative Management of AO Type 44 Ankle Fractures: Determinants of Outcome

The consequences of inadequate treatment of ankle fractures can be disastrous. We assessed the radiologic and functional outcomes, postoperative quality of life (QOL), and its determinants for patients treated operatively for AO type 44 ankle fractures. Evidence is lacking concerning the management of posterior malleolus fractures and syndesmotic injuries. Our retrospective adult cohort study included 432 AO/OTA type 44 ankle fractures (431 patients). The median follow-up period was 52 months. Outcomes were assessed from the medical records, radiographs, American Orthopaedic Foot and Ankle Society (AOFAS) ankle scale (functional outcome), and EuroQol EQ-5D questionnaires. The median AOFAS scale score was 88; 27.9% of patients reported restricted mobility and 40.4% pain or discomfort. In 8.8%, radiographic failure was observed. The presence of posterior malleolus fractures was significantly associated with poor functional outcomes, and a postoperative step-off correlated with radiologic failure, poor functional outcome, and poor postoperative QOL. Late syndesmotic screw removal was associated with worse EQ-5D time trade-off QOL scores. A substantial number of patients experienced functional impairment, discomfort, and pain. Syndesmotic injury was associated with ankle joint failure and poor functional outcomes. Our data indicate that all displaced posterior malleolus fracture fragments affecting the posterior articular tibial surface in patients aged ≤65 years require anatomic reduction.

When and how to operate the posterior malleolus fragment in trimalleolar fractures: a systematic literature review

OBJECTIVES

Whether or not and how to fixate the posterior malleolus fracture seems to depend on the fracture fragment size and its amount of dislocation, but clear guidelines for daily practice are lacking. In this review, we summarize the literature on preferred treatment of the posterior fragment in trimalleolar fractures.

METHODS

A systematic review of publications between January 1995 and April 30 2017 on this topic in the PubMed, Embase, and Cochrane databases was performed according to the PRISMA statement.

RESULTS

Seventeen (2 prospective and 15 retrospective) of the 180 identified studies were included. Six studies report on indications for fixation of posterior malleolus fracture fragments. Eleven studies compare different fixation approaches and techniques for the posterior fragment. Meta-analysis was not possible due to varying fixation criteria and outcomes. There was no clear association between posterior fragment size and functional outcome or development of osteoarthritis. The non-anatomical reduction of the fragment was of more influence on outcome. Radiological and functional outcome was better after open reduction and internal fixation via the posterolateral approach than after percutaneous anterior-to-posterior screw fixation.

CONCLUSION

The posterior fragment size is not a clear indication for its fixation. A step-off, however, seems an important indicator for developing posttraumatic osteoarthritis and worse functional outcome. Posterior fragments involving the intra-articular surface need to be reduced and fixated to prevent postoperative persisting step-off. Furthermore, fixation of the posterior malleolus via an open posterolateral approach seems superior to percutaneous anterior-to-posterior fixation. However, these results need to be confirmed in a prospective comparative trial.

LEVEL OF EVIDENCE

Therapeutic level II.

Impact of Computed Tomography on Operative Planning for Ankle Fractures Involving the Posterior Malleolus

BACKGROUND

The purpose of this study was to (1) Determine the effect of computed tomography (CT) on identification of fractures involving the posterior malleolus, (2) determine its effect on operative indications, and (3) determine its effect on the overall operative plan.

METHODS

Patients with ankle fractures involving the posterior malleolus were identified. Only injuries with complete preoperative plain radiographs and a CT scan were included. Spiral tibia fractures and pilon variants were excluded. The plain radiographs were deidentified, randomized, and presented to 3 orthopedic surgeons. They were asked 3 questions: (1) Is this fracture simple or complex? (2) Does the injury require direct visualization and reduction? and (3) How would you position the patient and approach the fracture? The same process was repeated for the CT scans. A total of 376 posterior malleolus injuries were identified and 25 met the inclusion criteria.

RESULTS

A complex fracture pattern was identified on 44% of plain radiographs and 56% of CT scans. The surgeons chose to operate in 84% of cases based on plain radiographs and 92% of cases based on CT scan. The observers changed their operative approach or positioning 44% of the time after reviewing CT images. The interobserver and intraobserver correlation coefficients were moderate.

CONCLUSION

The use of CT scan changed operative positioning and approach in 44% of cases. There was no significant change in characterization or operative indications when comparing plain radiographs to CT scan. CT scan may be a valuable tool in the management of ankle fractures involving the posterior malleolus.

LEVEL OF EVIDENCE

Diagnostic Level III, comparative series.

The Role of Computed Tomography in Surgical Planning for Trimalleolar Fracture. A Survey of OTA Members

OBJECTIVE

Does the additional information provided by computed tomography (CT) alter surgeons' treatment plans for trimalleolar ankle fracture?

DESIGN

Prospective.

SETTING

Electronic survey.

PATIENTS/PARTICIPANTS

Members of the OTA.

INTERVENTION

Compare management of trimalleolar ankle fracture before and after CT.

MAIN OUTCOME MEASUREMENTS

Compare types of fixation used, indication for fixation, and approach need for fixation before and after CT.

RESULTS

Overall, OTA members' operative technique changed in 430 of the 1710 (25.1%) cases after review of the CT images. Of the 430 observations in which the operative technique was altered, the surgeon had initially stated that they would not have requested a CT in 51.2% incidences. When analyzing if CT affected whether or not operative fixation was indicated, a total of 16.3% responses changed. Surgeons were significantly more likely to change from no fixation to fixation (11.5%) than vice versa (4.8%) after reviewing CT imaging. A total of 17.8% of responses changed operative approach after reviewing the CT; 11.7% changed to open reduction internal fixation, whereas 6.1% changed away from open reduction internal fixation.

CONCLUSION

A consensus on the ideal treatment of trimalleolar fractures remains elusive, evidenced by a high variation in treatment preference, both before and after CT review. Our results demonstrate with the additional information delineated on CT, a surgeons' operative plan, technique, and approach often change. With greater than 25% of respondents changing their treatment strategy after seeing CT imaging, radiographs alone limited surgeon understanding of fracture pattern. Because of difficulty understanding the posterior fracture fragment, we recommend preoperative CT on all trimalleolar fractures.

LEVEL OF EVIDENCE

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

Posterior Malleolar Fractures: Changing Concepts and Recent Developments

Injuries to the posterior malleolus are of prognostic relevance in ankle fracture-dislocations. The three-dimensional outline of the fragments as reflected by computed tomography classification, involvement of the fibular notch, and the presence of intercalary fragments seem to be of greater therapeutic relevance than the size of the fragment and amount of the articular surface involved. Operative treatment aims at reconstruction of the posterior tibial plafond, the fibular notch, and the integrity of the posterior inferior tibiofibular syndesmosis. Direct open reduction and fixation of posterior malleolus fragments via posterior approaches is biomechanically more stable than indirect reduction and anteroposterior screw fixation.

Medium-sized posterior fragments in AO Weber-B fractures, does open reduction and fixation improve outcome? the POSTFIX-trial protocol, a multicenter randomized clinical trial

BACKGROUND

Guidelines for treatment of the posterior fracture fragment in trimalleolar fractures are scarce and show varying advices. Did the increasing size of the posterior fragment seem to relate to worse outcome in the past, nowadays this has changed to the amount of dislocation of the posterior fragment post-operatively. Despite many retrospective cohort studies and some prospective cohort studies, no consistent guideline could be derived from the current literature.

METHODS

The POSTFIX-study is designed as a multicenter randomized clinical trial to analyse the effects of anatomical reduction and fixation of the posterior fragment in AO 44-B3 fractures with medium-sized posterior fragment. A total of 84 patients will be included and online allocated to either anatomical reduction and fixation of the posterior fragment via the posterolateral approach (n = 42) or no fixation of the posterior fragment (n = 42). The concomitant fractured medial and lateral malleoli are treated according to the AO-principles. Functionality of the ankle as measured by the AAOS-questionnaire (American Association of Orthopaedic Surgeons) 1 year post-operatively was set as primary outcome. Main secondary outcome measures are the AAOS-questionnaire 5 years postoperatively and osteoarthritis as measured on plain radiographs 1 year and 5 years post-operatively. The Olerud and Molander score, the AOFAS-score, the VAS-pain, the Euroqol-5D and Range of Motion by physical examination will also be evaluated during the follow-up period.

DISCUSSION

The POSTFIX-trial is the first high quality multicenter randomized clinical trial worldwide to analyse the effects of anatomical fixation of the posterior fragment in trimalleolar fractures. New guidelines on anatomical reduction and fixation of the posterior fragment can in future be based on the results of this trial.

TRIAL REGISTRATION

This trial is registered on ClinicalTrials.gov with reference number: NCT02596529 . Registered 3 November 2015, retrospectively registered.

The treatment options for posterior malleolar fractures in tibial spiral fractures

PURPOSE

The posterior malleolar fracture (PMF) in tibial spiral fractures are a common type of complication that occurs in tibial fractures. However, the indication of fixation for posterior fractures is still under debate and varies between different surgeons'. It is not unusual to find the smaller PMF (<25%), which could be treated conservatively within guidelines, treated with internal fixation in clinic. The aim of this study is to evaluate the clinical outcomes of tibial spiral fractures with PMF and provide proper guidance for the treatment of this special fracture.

METHODS

A total of 284 cases of spiral fractures combined with PMF were collected and analyzed. Demographic data, fragment size (classified by 25% involvement of ankle joint), time to weight-bearing and functional scores post-operatively were recorded. The ankle-hindfoot scale of the American Orthopaedic Foot and Ankle Society (AOFAS), a visual analogue scale (VAS) pain score, assessment of dorsiflexion restriction and arthritis scale were used as the main evaluations.

RESULTS

Forty patients with a larger PMF (≥25%) and 72 with smaller ones (<25%) were fixed and categorized as the fixation group (FG). In the nonfixation group (NG), the corresponding numbers were four and 168 patients respectively. A total of 279 PMF were classified as large posterolateral triangular fragment carrying the posterior half of the fibular notch and intra-incisural posterolateral fragment involving one-fourth to one-third of the fibular notch. However, no obvious differences were observed in terms of the clinical outcomes in PMF involving one-fourth to one-third of the fibular notch. In the treatment of smaller PMF (<25%) of this type, there were no obvious differences in the functional outcomes between fixed (SF) and nonfixed PMF (SN).

CONCLUSIONS

Many patients with smaller PMFs were fixated, but functional outcomes of SF were not better than those of SN. There is no need to emphasize other factors guiding the treatment of PMF involving one-fourth to one-third of the fibular notch in spiral fractures. The traditional size of PMF may be only enough to guide the treatment of spiral fracture with PMF. But other types of PMF should still be treated considering morphology and fragment simultaneously.

Posterior Malleolus Fractures

Posterior malleolus fractures vary in morphology. A computed tomography scan is imperative to evaluate fragment size, comminution, articular impaction, and syndesmotic disruption. Despite an increasing body of literature regarding posterior malleolus fractures, many questions remain unanswered. Although, historically, fragment size guided surgical fixation, it is becoming evident that fragment size should not solely dictate treatment. Surgical treatment should focus on restoring ankle joint structural integrity, which includes restoring articular congruity, correcting posterior talar translation, addressing articular impaction, removing osteochondral debris, and establishing syndesmotic stability.

Articular Gap and Step-off Revisited: 3D Quantification of Operative Reduction for Posterior Malleolar Fragments

OBJECTIVES

Despite advanced imaging techniques, classic measurements of fracture reduction have not been revisited to date. The purpose of this study was to evaluate the reliability of innovative measurement techniques to quantify operative fragment reduction of posterior malleolar fractures by quantification of three-dimensional computed tomography (Q3DCT).

METHODS

Twenty-eight ankle fractures including a posterior malleolar fragment (AO/OTA type 44) were evaluated using 2DCT and Q3DCT to postoperatively quantify fragment reduction. "Classic" maximum gap and step-off of the posterior fragment were measured on 2DCT and Q3DCT. In addition, 2 innovative Q3DCT parameters were introduced and their reliability was tested using intraclass correlations (ICCs): gap surface (mm) and multidirectional 3D-displacement (mm).

RESULTS

"Classic" measurements showed a median maximum step-off of 1.1 mm [interquartile range (IQR) 0.0-1.8 mm] on 2DCT versus a median step-off of 0.6 mm (IQR 0.0-1.1) on Q3DCT. Median maximum gap was 1.2 mm (IQR 0.0-3.8) on 2DCT, and its equivalent on Q3DCT showed no median displacement. Q3DCT measurements revealed a median gap surface of 14.5 mm (IQR 4.7-30.0) and a median multidirectional 3D-displacement of 0.7 mm (IQR 0.0-1.1). Interrater reliability of these new Q3DCT parameters of displacement was excellent (ICC 0.92, 95% CI 0.79-0.98) for gap surface and good (ICC 0.64, 95% CI 0.28-0.88) for 3D-displacement.

CONCLUSIONS

Q3DCT is a reliable and promising technique for postoperative evaluation of fracture fragment reduction. In addition to "classic" gap and step-off measurements, we propose to explore total gap surface and 3D-displacement as innovative radiographic measurements in future clinical studies.

LEVEL OF EVIDENCE

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