An evolution in the management of fractures of the ankle

Considerations with Fractures of the Posterior Malleolus in Ankle Fractures

Foot and ankle surgeons are commonly confronted with the surgical dilemma on when and how to best surgically address trimalleolar ankle fractures with a posterior malleolar component. This may involve either direct fixation of the posterior malleolus or indirect stabilization with the fixation of the medial and lateral malleoli and trans-syndesmotic fixation. Recently there has been a paradigm shift in the management of these injuries with a more thorough understanding of anatomy, stability, and long-term sequela of these injuries. This article aims to evaluate the current literature on posterior malleolar ankle fractures, approaches to fixing the posterior malleolus, and outcomes and complications of these procedures.

Safety of the modified posteromedial approach in complex ankle fractures: Comparative analysis versus posterolateral access

INTRODUCTION

The aim of the study was to evaluate the safety of the modified posteromedial approach (MfPM) in the surgical management of complex ankle fractures in terms of local complications.

METHODS

Retrospective multicenter review of a series of malleolar fractures surgically treated by posterior ankle approaches between 2016 and 2022. Two approaches were used. In the MfPM group patients were placed in a prone position and the incision was made 1 cm medially to the Achilles tendon. In the posterolateral access (PL) group patients were placed in a prone or lateral decubitus position and the incision was made between the lateral malleolus and the Achilles tendon. Complications evaluated were divided into wound complications, infections, neuritis, vascular alterations and others.

RESULTS

81 ankle fractures with a posterior malleolar fragment treated by open reduction and internal fixation were identified. 20 cases were approached through the MfPM approach and 61 through the PL access. The mean follow up was 18.60 months (range 4-78 months). In the MfPM group the local complication rate was 10% (2/10 patients), both corresponding to minor wound problems which required no surgical intervention. No infection or other neural or vascular complications were found. In the PL group a complication rate of 8,19% (5/61 patients) was found, all of them corresponding to minor wound problems which required no surgical intervention. No infection or other neural or vascular complications were found. There were no significant differences between the two approaches regarding postoperative local complications (z score 0.249 - P: 0.803).

CONCLUSION

The MfPM approach is safe and may become as readily used as the PL due to the low incidence of postoperative local complications, especially in fractures with a large fragment and posteromedial extension in which greater access to the posterior pilon can facilitate instrumentation for anatomic reduction and fixation.

Morphological analysis and classification of posterior malleolar fractures based on CT scans

OBJECTIVES

The aim of the study was to propose a classification system of posterior malleolar fractures by fracture lines with the use of CT scans, including 3D CT reconstruction, which can better understand morphological characteristics, analyze the mechanism and guide the surgeon to choose the optimal approach and fixation.

METHODS

Patients with OTA/AO type 44 fractures involving the posterior malleolus and preoperative CT scans were included. We retrospectively analyzed 128 consecutive patients with posterior malleolar fractures from January 2013 to December 2019 at our institution. CT data were loaded into Mimics software (V20.0, Materialize), in which 3D CT reconstruction, morphological analysis and data measurements were made.

RESULTS

Based on the number of fracture lines in 128 consecutive patients, posterior malleolar fractures were classified into three types: type 1 with a single fracture line, type 2 with double fracture lines and type 3 with multiple fracture lines. According to the distribution of the fracture line, type 1 was divided into types 1A, 1B and 1C, and type 2 was divided into types 2A, 2B and 2C. The fracture line from the fibular notch to the posterior rim of the distal tibia was defined as type 1A, and the fracture line to the medial malleolus was defined as type 1B. Type 1C was a small fragment in the posterior rim of the distal tibia. Type 2A was regarded as type 1A with type 1C. It was considered type 2B because another fracture line started from the fracture line of type 1A and extended to the medial malleolus. In type 2C, we could see that the double fracture lines were all from the fibular notch to the posterior rim of the distal tibia and did not cross. Type 3 fractures were comminuted fractures with multiple fracture lines.

CONCLUSION

The morphology of posterior malleolar fractures, involvement of the fibular notch, or the medial malleolus can be obviously assessed by our classification system. We found the relation of the injury mechanism between type 1 and type 2 by comparing the area of the fragment. We have indicated that each type of fracture corresponds to its associated injury mechanism and which surgical approach and fixation can be chosen.

Direct fixation of posterior malleolus fractures-posterolateral or posteromedial approach?

Ankle fractures involving the posterior malleolus (PM) generally have worse prognosis. There is a trend towards it's direct fixation, yet the exact indications are a subject of debate. The purpose of our study was to present our treatment protocol and to discuss the advantages and limitations of the direct posterolateral and posteromedial approaches. We present a prospective series of 35 ankle fractures involving the PM, operated for a period of 4 years (2018-2022). Direct posterolateral approach was used in 20 ankles, 15 were operated via a posteromedial approach. Clinical and functional assessment was performed according to the criteria of AOFAS. 14 patients received an excellent score, 16 had good and the rest had an average score. The overall score was 85,4 (54-100). The average range of motion was 50° (15°-55°).Eight patients had superficial skin necrosis along the surgical incision. Thirteen patients need their fibular plates removed due to local irritation. Five patients, operated through a posterolateral approach, had lateral heel numbness suggestive of a sural nerve disfunction. PM is important for normal ankle kinematics. When it's direct fixation is considered appropriate, the safest and shortest route is optimal. It is determined by the preoperative CT. The posterolateral approach is more versatile, but lead to more complications in our 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.

Trimalleolar Fractures Treated by Open Reduction Internal Fixation Compared With Arthroscopically Assisted Reduction and Minimally Invasive Surgery

BACKGROUND

Currently, the standard of treatment for trimalleolar (TM) fracture is osteosynthesis through open reduction and internal fixation (ORIF). This study assessed whether arthroscopically assisted reduction and minimally invasive surgery (AARMIS) can be an alternative surgical method for TM fractures.

METHODS

This retrospective cohort study included 49 patients with TM that were surgically treated. 27 patients received ORIF and 22 patients underwent AARMIS . At baseline, we recorded the patient's demographic features, fracture pattern (AO-OTA and Haraguchi classification), and surgical method. For postoperative results, we examined the patient's radiographic outcome, including time to union, quality of fracture reduction, as well as functional outcomes (American Orthopaedic Foot & Ankle Society ankle hindfoot score, ankle range of motion, and visual analog scale of pain) and perioperative complications.

RESULTS

At mean follow-up of 46.6±24.6 (ORIF) and 36.4±18.5 months (AARMIS), both groups had comparable radiographic outcomes. No significant difference in rates of early ankle OA were detected. In terms of functional outcome, VAS pain and AOFAS score at postoperative day 3, postoperative month 3, and at final follow-up were not different. In terms of range of motion, we did not find a significant difference in mean range of motion.

CONCLUSION

Patients with TM fractures treated with AARMIS achieved satisfactory results and was not significantly different in radiographic and functional performance compared with ORIF.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Morphological study of CT image of posterior pilon variant fracture and its possible clinical significance

OBJECTIVE

The incidence of posterior pilon variant fractures has been underestimated. The purpose was to study the characteristics of posteromedial (PM) and posterolateral (PL) fragments in CT imaging of posterior pilon variant fractures, and to provide help for clinical diagnosis and treatment.

METHODS

CT imaging data of 109 cases of posterior pilon variant fractures in our hospital from January 2013 to December 2020 were retrospectively analyzed. According to Mason and Molloy classification, PM fragments were further divided into pilon subtypes and avulsed subtypes. The largest actual area of fragments in axial and sagittal were selected as the study plane, and the maximum axial lengths of X, Y and Z, α angle, β angle, fragment area (S1-7) and fragment area ratio (FAR1-4), interfragmentary (IF) angle, and back of tibia (BT) angle were measured.

RESULTS

A total of 109 cases were included in this study, 61 of whom were pilon subtypes [90.16% were supination-external rotation (SER) injuries]. 48 cases were avulsed subtypes [81.25% were pronation-external rotation (PER) injuries]. Pilon subtypes were larger than avulsed subtypes in X, Y, Z, α₂ Angle, β₂ Angle, fragment area and ratio, and IF and BT angle (P < 0.05). There was no difference between α₁ and β₁ angle (P > 0.05).

CONCLUSION

The morphology of pilon subtype was larger than that of avulsion subtype. According to fragment size, morphology, and injury mechanism, two fragments of pilon subtype should be anatomic reduction and fixation. However, the PL fragment of avulsion subtype should to be fixed, while PM fragment may only need conservative treatment.

[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.

Ankle fractures involving the posterior malleolus: patient characteristics and 7-year results in 100 cases

INTRODUCTION

The presence of a posterior malleolar (PM) fragment has a negative prognostic impact in ankle fractures. The best treatment is still subject to debate. The aim of this study was to assess the medium-to-long-term clinical and functional outcome of ankle fractures with a PM fragment in a larger patient population.

MATERIALS AND METHODS

One hundred patients (69 women, 31 men, average age 60 years) with ankle fractures including the PM were evaluated clinically and radiographically. Patients with Bartoníček-Rammelt type 3 and 4 fracture displayed a significant female preponderance. Fixation of the PM was performed in 63% and tailored to the individual fracture pattern.

RESULTS

Internal fixation of the PM fragment was negatively correlated with the need for syndesmotic screw placement at the time of surgery (p = 0.010). At an average follow-up of 7.0 years, the mean Foot Function Index (FFI) was 16.5 (SD: 21.5), the Olerud Molander Ankle Score (OMAS) averaged 80.2 (SD: 24) and the American Orthopedic Foot & Ankle Society (AOFAS) ankle/hindfoot score averaged 87.5 (SD: 19.1). The maximum score of 100 was achieved by 44% of patients. The physical (PCS) and mental health component summary (MCS) scores of the SF-36 averaged 47.7 (SD: 12.51) and 50.5 (SD: 9.36), respectively. Range of motion was within 3.4 (SD: 6.63) degrees of the uninjured side. The size of the PM fragment had no prognostic value. There was a trend to lower outcome scores with slight anterior or posterior shift of the distal fibula within the tibial incisura. Patients who underwent primary internal fixation had significantly superior SF-36 MCS than patients who underwent staged internal fixation (p = 0.031).

CONCLUSIONS

With an individualized treatment protocol, tailored to the CT-based assessment of PM fractures, favorable medium and long-term results can be expected.

Morphological analysis of posterior malleolar fractures with intra-articular impacted fragment in computed tomography scans

Background

Intraarticular impacted fragment (IAIF) of posterior malleolar fractures has been reported by a few studies. However its location, morphology, and the correlation of posterior malleolar fractures have not been described in detail. The aim of this study was to describe the morphology of IAIF in posterior malleolar fractures, to analyze the related factors between IAIF and posterior malleolar fragments, and explore the treatment of IAIF.

Materials and methods

Between January 2013 and December 2018, 108 consecutive patients with unilateral posterior malleolar fractures were managed in our hospital. Basic demographic and computed tomography (CT) data were collected and classified by Lauge–Hansen, OTA/AO, Haraguchi, and Mason classification. Additional radiographic data, including the length and area of posterior malleolar fragment, IAIF, and stable tibial plafond were measured. The location of IAIF was described, and involvement of the fibular notch and medial malleolus was also observed. Statistics were analyzed based on univariate analysis (Chi-square test, t-test, Mann–Whitney U test, Fisher’s test) and Spearman’s correlation test.

Results

Among the 108 cases of posterior malleolar fractures, 75 (69.4%) were with IAIF and 33 (30.6%) cases were without. There were 74 (68.5%) females and 34 (31.5%) males, and the average age of the patients was 49 years (18–89 years). The average L_IFN/(L_IFN + L_SFN) [length of involving fibular notch/(length of involving fibular + length of stable notch fibular notch)] was 32.9% (11.6–64.9%). The A_PMF/(A_PMF + A_STP + A_IAIF) [area of posterior malleolar fragment/(area of posterior malleolar fragment + area of IAIF + area of stable tibial plafond)] and A_IAIF/A_PMF (area of IAIF/area of posterior malleolar fragment) were 13.1% (0.8–39.7%) and 52.6% (1.2–235.4%), respectively. Involvement of medial malleolus (fracture line extended to medial malleolus, P = 0.022), involvement of fibular notch (P = 0.021), L_IFN/(L_IFN + L_SFN) (P = 0.037), L_MPMF (P = 0.004), and A_PMF were significantly related to the occurrence of IAIF.

Conclusion

Our research indicates a high incidence of IAIF in posterior malleolar fractures. All IAIFs were found in posterior malleolar, and the most common location was within the lateral area A. Posterior malleolar fracture lines that extend to medial malleolus or fibular notch herald the incidence of IAIF. L_IFN/(L_IFN + L_SFN), L_MPMF and A_PMF are also associated with the incidence of IAIF. CT scans are useful for posterior malleolar fractures to determine the occurrence of IAIF and make operational plans. Operation approach selection should be based on the morphology of posterior malleolar fragments and the location of IAIF.

Level of evidence

Level III, retrospective case analysis.

The Association Between Lateral Radiographs and Axial Computed Tomography of Posterior Malleolar Fractures as a Tool for Predicting Medial Malleolar Extension: A Multi-Center Retrospective Analysis

Posterior malleolar fractures are often part of complex ankle fracture patterns. Radiographs and computed tomography are often obtained in the preoperative setting. In this study, we compared measurements from lateral ankle radiographs with measurements on axial computed tomography. We hypothesize that there is an association between measurements taken on lateral XR and certain fracture morphology such as medial extension and that measurements taken on lateral XR can be used to predict likelihood of medial extension type fractures. A multi-center retrospective analysis was performed involving patients with trimalleolar ankle fractures treated at two large urban healthcare systems ranging from January 1, 2010 to November 1, 2019. A total of 279 patients met criteria including 186 females and 93 males aged 18 to 90 with an average age 55. Four reviewers measured continuous variables on lateral radiograph and axial computed tomography: posterior malleolus fracture height, articular surface length, medial-lateral width, and anterior-posterior depth and then agreement was assessed via intraclass correlation coefficient. Pearson correlations were calculated for all pairwise combinations of measurements. Two fracture classification systems were then evaluated for association with the continuous variables. Lateral height was divided into quartiles and analyzed for the degree of association. Positive correlation was found between lateral height and axial depth/axial width. Taller lateral height values were statistically associated with medial extension type fractures. Lateral height 24.5mm-29.5mm is 3.1x higher, and lateral height >29.5mm is 8.6x more likely to have medial extension when compared to shorter lateral heights(<20.5mm). Based on these findings we suggest increased usage of pre-operative CT and evaluation for the use of posteromedial approaches in the setting of taller lateral height fracture patterns(>24.5mm) as seen on lateral XR.

Defining a Safe Zone for Percutaneous Screw Fixation of Posterior Malleolar Fractures

Posterior malleolar fractures require fixation to confer stability to the ankle. Although some have suggested that fractures involving less than 25% of the articular surface require no intervention, estimation of malleolar size on plain imaging is inaccurate. Some posterior malleolar fractures may be particularly suitable for posterior-to-anterior percutaneous screw fixation of the posterior malleolus via a posterolateral approach. We hypothesized that there may be a safe zone in the posterolateral ankle, identifiable with reliable anatomic landmarks, that might allow safe percutaneous screw placement for fracture fixation. The study protocol involved Step 1, in which multiple Kirschner wires were used in a single cadaveric specimen to attempt to identify a safe zone entry point in the posterior ankle, and Step 2, in which a single wire was used in each of six additional cadaveric specimens to test the ability to safely replicate the use of that entry point. In Step 1, a safe zone entry point was identified, located immediately lateral to the Achilles tendon and 1 cm above the level of the tip of the medial malleolus, when visualizing the posterior ankle. In Step 2, using these landmarks and an image intensifier, single wires were then successfully placed in the other six specimens without injury to any significant structure. If confirmed in clinical studies, the safe zone entry point that we have identified could potentially be used to facilitate posterior-to-anterior percutaneous fixation in patients with posterior malleolar fractures for whom open reduction may not be required or may be contraindicated.

Posterior Malleolar Fractures: A Critical Analysis Review

In patients with ankle fractures, the presence of a posterior malleolar fracture has a negative impact on the prognosis. Computed tomography (CT) scanning is essential for fracture classification and treatment planning, as the indication for surgery depends on the 3-dimensional fragment outline and displacement, incisura involvement, and the presence of joint impaction. Anatomic reduction of a posterior malleolar fragment restores the incisura, facilitating reduction of the distal part of the fibula, and it also restores the integrity of the posterior portion of the syndesmosis, reducing the need for additional syndesmotic stabilization. Direct open reduction and fixation of posterior malleolar fragments from a posterior orientation is biomechanically more stable and provides a more accurate reduction than does indirect reduction and anterior-to-posterior screw fixation. Intra-articular step-off of >=2 mm is an independent risk factor for an inferior outcome and the development of posttraumatic arthritis, irrespective of the fragment size.

[Open reduction and internal fixation of posterior malleolus fractures]

OBJECTIVE

Stabilization of the syndesmotic complex by open reduction and internal fixation (ORIF) of the posterior malleolus, restoration of the tibial articular surface, stability of the ankle, posterior tibiofibular ligament and the incisura tibiae, reduction of the fibula into the incisura tibiae by ligamentotaxis.

INDICATIONS

Unstable ankle fractures (OTA/AO type 44-B3, C1.3, C2.3, C3.3) with involvement of the posterior malleolus (type II-IV according to Bartoníček and Rammelt).

CONTRAINDICATIONS

Critical general condition, circulatory disorders, severe soft tissue swelling (if necessary, first external fixator), percutaneous treatment the better alternative.

SURGICAL TECHNIQUE

Positioning in unstable lateral position, dorsolateral approach dorsally of the peroneal tendons, incision of the superficial and deep fascia, retraction of the flexor hallucis longus tendon medially, visualization of the posterior malleolus, reduction and fixation. To treat the lateral malleolus fracture, preparation of a full-thickness flap above the peroneal tendons on the fibula, treatment according to AO principles. For the treatment of the medial malleolus positioning in supine position without changing the sterile covers, medial approach for the medial malleolus, wound closure.

POSTOPERATIVE MANAGEMENT

Six weeks partial weight bearing (20 kg), early functional exercise, exercise of the flexor hallucis longus muscle; transition to full weight bearing after clinical and radiological follow-up after 6 weeks RESULTS: Few clinical results on open ORIF of the posterior malleolus have been published. However, most studies found that ORIF resulted in better reconstruction of the distal articular surface and the tibial incisura, better reduction of the fibula into the tibial incisura, stabilization of the distal tibiofibular joint and better clinical results, regardless of fragment size, when compared to closed reduction or untreated fragments.

Posterior approaches to the ankle - an analysis of 3 approaches for access to the posterior malleolar fracture

BACKGROUND

An anatomical study to determine what degree of access to the posterior distal tibia could be gained by using 3 different approaches; the posterolateral, the posteromedial and the medial posteromedial approaches.

METHODS

A comparison study, between the anatomical dissection of 7 fresh frozen cadaveric lower legs and image analysis of CT data of posterior malleolar fractures from a prospectively collected database was conducted. All fractures have been classified using the Mason and Molloy classification.

RESULTS

In comparing the posterior malleolar fracture fragment width to distal tibia width, the posterolateral fragment encompasses 60.1% (95% CI 56.8, 63.3) of the total width of the tibia. If the posteromedial fragment is included the fragments encompass the entire distal tibia (100%). In type 3 fractures, 81.4% (95% CI 75.5, 87.1) of the distal tibia width is involved. When comparing the fracture width to the approach, no approach achieves a complete exposure of the type 2B or 3 fracture patterns. The overall surface area of the type 2B and 3 fractures, is significantly greater than all the approaches. Considering the lateral to medial extent of the fracture, the posterolateral fragment mean width is 33% greater than what can be exposed by the posterolateral approach (mean 24.9 vs 16.8mm). In type 2B and 3 fractures, the horizontal exposure reduces to 39.8% and 47.6% respectively. In comparison, the PM approach exposes 47.6% of the type 2B fracture pattern and 57.1% of the type 3 fracture pattern and allows a preferable angle for hardware insertion. The MPM approach does not expose any of the posterolateral fragments in this study, however it does expose 92% (mean 21.9 vs. 23.8mm) of the medial to lateral width of a posteromedial fragment of a type 2B fracture.

CONCLUSION

Each approach allows access to different parts and amounts of the posterior tibia. An understanding of and utilisation of these approaches can lead to adequate exposure for fixation of most posterior malleolus fracture patterns seen.

Comparison of four posterior approaches of the ankle: A cadaveric study

OBJECTIVES

The purpose of this study is to provide a detailed comparison of 4 posterior approaches of the ankle: the posteromedial, modified posteromedial (mPM), Achilles tendon-splitting (TS), and posterolateral approaches.

METHODS

Cadaveric dissections were performed to assess the influence of the medial and lateral retraction forces on the neuro-vascular bundle with suspension scales and to measure the medial and lateral exposed areas of the posterior tibia and talus. Data was acquired with the ankle in neutral position and in plantar flexion.

RESULTS

Both the mPM and TS approaches provided excellent visualization of the posterior tibia with the ankle in plantar flexion (16.6 cm2 and 16.2 cm2, respectively). The medial aspect of the posterior tibia, however, was significantly better exposed in the mPM approach than in the TS approach with the ankle in neutral position (8.9 cm2 vs 6.5 cm2). The lower value for medial retraction force in the mPM approach (1.9 N in neutral position and 0.9 N in plantar flexion) indicated a lower risk of injury to the neuro-vascular bundle (the tibial nerve and the posterior tibial artery). The posterior talus, however, is best visualized through the TS approach with the ankle in neutral position (4.5 cm2).

CONCLUSIONS

The current study demonstrated the usefulness of the mPM approach. When internal fixation of the fibula is unnecessary, the mPM approach is preferable, considering the potential damage to the Achilles tendon associated with the TS approach.

Quantitative evaluation of posterior talar subluxation in posterior malleolar fractures: A preliminary study

BACKGROUNDS

Although ankle posterior subluxation is one of the major mechanisms by which posterior malleolar fractures (PMF) contribute to a worse prognosis, there is no parameter to address it quantitatively. So, we suggest a method that can evaluate posterior talar subluxation quantitatively in PMF.

METHODS

We retrospectively analyzed 37 patients with posterior malleolar fractures. The patients were divided into two groups: PMF without posterior talar subluxation (n = 18) and with posterior talar subluxation (n = 19). We measured the distance between the arc center of the talus and the anterior tibia (TAD), the percentage of articular involvement of the fracture fragment, the inter-fragment distance (IFD) and articular step-off. We analyzed significant differences and the correlations between the two groups for each index. The estimated area of the receiver operating characteristic (ROC) curve was calculated, and cutoff values were suggested to discriminate posterior talar subluxation.

RESULTS

TAD, IFD, and articular step-off were significantly greater in patients with posterior talar subluxation. (TAD: 14.3 vs. 2.8 mm, p < 0.001, IFD: 7.8 vs. 4.0 mm, p < 0.001, articular step-off: 3.6 vs. 2.0 mm, p = 0.004). The ROC curve showed that TAD was most useful to determine cutoff values for posterior talar subluxation. The area under the curve for TAD was 1.000, and the appropriate cutoff value was 5 mm. When a TAD of > 5 mm was used as a threshold, a sensitivity of 100% and a specificity of 100% were achieved in determining the presence of posterior talar subluxation. Also, higher TAD was correlated with IFD and articular step-off.

CONCLUSIONS

TAD can be a useful parameter for evaluating the posterior talar subluxation in PMF. It can reflect not only the degree of fracture displacement but also posterior talar subluxation quantitatively.

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.

Posterior malleolar fractures: A CT guided incision analysis

AIM

The aim of this study was to determine the most appropriate approaches for fixation of each type and fragment of posterior malleolar fractures.

MATERIALS AND METHODS

A retrospective analysis of a prospectively collected database was performed on 141 posterior malleolar fractures. On the CT scan axial slice, a clock face was drawn using the posterolateral corner of the tibia as the centre and the Achilles tendon as the 6 o'clock axis. A box was then drawn from the fracture plane, with 90-degree lines corresponding to the medial perpendicular line (MPL) and lateral perpendicular line (LPL) extremity of the fracture and a central perpendicular line (CPL) (i.e. orthogonal central plane, for optimum screw placement). It was recorded where the MPL, LPL and CPL exited the clock face. All fracture patterns were further assessed by both senior authors regarding their choice of approach based on CPL and all variances resolved by discussion.

RESULTS

The LPL was equivalent across the groups (except for the 2B medial fragments), indicating a consistent posterolateral corner fragment throughout the posterior malleolar sub types (p = 0.25). The medial aspect (MPL) of the type 1, type 2A and posterolateral fragments of type 2B were equivalent. The MPL of type 3 fractures was significantly more medial than type 1 and 2A fractures (p < 0.05), with the medial extremes of the type 2B posteromedial fragment being further medial. The majority of type 2B fractures (2/3rds) were determined to be best accessed through a combined posterolateral and medial posteromedial approach, with the other third via the posteromedial approach. Almost all type 3 fractures could be appropriately accessed through the PM approach.

CONCLUSION

This study concludes that the extent of each subtype of posterior malleolar fractures are consistent. To fully expose each fracture differing incisions are necessary and should be in the skill mix for surgeons treating these fractures.

LEVEL OF EVIDENCE

4.

Mechanism of posterior malleolar fracture of the ankle: A cadaveric study

Objectives:

Ankle fracture treatment involves reduction of the bone fragments and stabilization of the joint by reversing the mechanics of injury. For posterior malleolar fracture however, the true mechanism is not understood, leading to a lack of consistent guidance on how to best treat this injury.

Methods:

Fifteen cadaver ankles were subjected to fracture loading that replicated the Lauge-Hansen pronation-external rotation mechanism. An axial load was applied to each specimen, which was mounted on a materials testing machine, and the foot was rotated externally to failure. Digital video cameras recorded the failure sequence of specific anatomic structures.

Results:

Posterior malleolar fracture occurred in 7 specimens. Of these, 1 was an intra-articular fracture, another was a fracture involving the entire posterior tibial margin consisting of 2 fragments: that of the posterior tubercle and that of the posteromedial margin of the tibial plafond, with the former judged to be a consequence of avulsion by the posterior inferior tibiofibular ligament and the latter a consequence of axial loading from the talus. In the remaining 5 specimens, the posterior malleolar fracture was a small extra-articular avulsion fracture.

Conclusions:

Fractures at the posterolateral corner of the distal tibia were shown to be avulsion fractures attributed to the posterior inferior tibiofibular ligament and produced by external rotation of the talus. A fracture involving the entire posterior tibial margin consisting of 2 fragments can be produced by a combination of avulsion by the posterior inferior tibiofibular ligament and axial loading from the talus.

Retrospective cohort study of operatively treated ankle fractures involving the posterior malleolus

BACKGROUND

Direct fixation of the posterior malleolus through a posterolateral approach is increasing in popularity. However, data is limited, and no studies have stratified results by posterior malleolus size.

METHODS

A retrospective cohort study of patients with posterior malleolus (PM) fractures undergoing internal fixation over an 18-month period was conducted. Radiographic and patient reported outcomes measures (PROMs) were assessed. 75 patients were included, and 31 returned Manchester-Oxford Foot and Ankle (MOXFQ), EQ-5D-3 L, 5-point Likert satisfaction questionnaires. Mean age was 56.2 years, 68% were female, mean ASA was 1.72, 6.7% were diabetic, and average surgical time was 75.7 min (±40.9).

RESULTS

Overall, the MOXFQ summary score was 26.9 (±25.8), with the pain domain showing the most severe score 32.4 (±24.0). The EQ-5D VAS index was 0.75 (±0.24). Larger PM size was associated with more anatomical reduction (58.8%, n = 20 of <10% vs. 90.9%, n = 10 of >30%) and larger sized fragments were more likely to be fixed posteriorly. Best PROMs were observed in PM fragments <10%, and the worst in fragments 10-20%. A tendency towards more secondary surgery was observed with posterior subluxation 21.9% (n = 7) vs. 7.0% (n = 3) (p = 0.06).

CONCLUSIONS

Patients with fragments >10% have an intra-articular injury. We recommend direct anatomic reduction and rigid internal fixation.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

CT controlled results of direct reduction and fixation of posterior malleolus in ankle fractures

PURPOSE

The aim of this study was to present outcomes of operative treatment of the posterior malleolus fractures of type four of the Bartoníček/Rammelt classification.

METHODS

In 19 patients, direct reduction and fixation of the posterior malleolus was performed from the posterolateral or posteromedial approaches. The accuracy of reduction was assessed with the use of postoperative CT scans.

RESULTS

The mean size of the avulsed articular surface carried by posterior malleolus amounted to 36%. Reduction of the posterior malleolus fracture was assessed as anatomical in 14 cases and as satisfactory in five cases. Position of the distal fibula was assessed as anatomical in 15 cases. The mean AOFAS score was 89.4 points. All nine patients with anatomical reduction of all lesions achieved the mean AOFAS score of 93.1 points, five patients with malposition of posterior malleolus 89.1 points and five patients with malposition of the fibula in the fibular notch 87.8 points. A total of six patients developed osteoarthritic changes of grades one and two according to the Kellgren and Lawrence classification.

CONCLUSIONS

Outcomes of the study demonstrated good mid-term results in type four fractures of the posterior malleolus treated by direct reduction from posterior approaches. Postoperative CT examination allowed evaluation of the accuracy of reduction of all fractures and reduction of the distal fibula into the fibular notch. Based on postoperative CT examination, it will be possible to assess the effect of reduction of individual lesions on the functional results.

Posterior Malleolar Ankle Fractures: An Effort at Improving Outcomes

Background:

There is increasing acceptance that the clinical outcomes following posterior malleolar fractures are less than satisfactory. We report our results of posterior malleolar fracture management based on the classification by Mason and Molloy.

Methods:

All fractures were classified on the basis of computed tomographic (CT) scans obtained preoperatively. This dictated the treatment algorithm. Type-1 fractures underwent syndesmotic fixation. Type-2A fractures underwent open reduction and internal fixation through a posterolateral incision, type-2B fractures underwent open reduction and internal fixation through either a posteromedial incision or a combination of a posterolateral with a medial-posteromedial incision, and type-3 fractures underwent open reduction and internal fixation through a posteromedial incision.

Results:

Patient-related outcome measures were obtained in 50 patients with at least 1-year follow-up. According to the Mason and Molloy classification, there were 17 type-1 fractures, 12 type-2A fractures, 10 type-2B fractures, and 11 type-3 fractures. The mean Olerud-Molander Ankle Score was 75.9 points (95% confidence interval [CI], 66.4 to 85.3 points) for patients with type-1 fractures, 75.0 points (95% CI, 61.5 to 88.5 points) for patients with type-2A fractures, 74.0 points (95% CI, 64.2 to 83.8 points) for patients with type-2B fractures, and 70.5 points (95% CI, 59.0 to 81.9 points) for patients with type-3 fractures.

Conclusions:

We have been able to demonstrate an improvement in the Olerud-Molander Ankle Score for all posterior malleolar fractures with the treatment algorithm applied using the Mason and Molloy classification. Mason classification type-3 fractures have marginally poorer outcomes, which correlates with a more severe injury; however, this did not reach significance.

Level of Evidence:

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

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.

Negative prognostic factors in surgical treatment for trimalleolar fractures

PURPOSE

Trimalleolar fractures are a common injury of the ankle that require surgical treatment to obtain an anatomic reduction of both malleoli and stabilization of the syndesmosis. This study aims to report the outcomes of surgical treatment for trimalleolar fractures, identifying the risk factors determining a worse result.

MATERIALS AND METHODS

Between January 2013 and December 2016, 48 patients with trimalleolar fracture treated with open reduction and internal fixation were retrospectively analyzed. The mean age was 44.69 years, and average body mass index (BMI) was 29.04. According to the Danis-Weber classification, 30 (62.5%) fractures were type B and 18 (37.5%) were type C. Clinical and radiographic evaluations at 3, 6, and 12 months were assessed. The functional results of Visual Analogue Staircases and Olerud-Molander (O&M) ankle score were reported.

RESULTS

No significant difference was found among the size of the PM in patients with and without ankle dislocation (p = 0.364). Therefore, there is no correlation between the size of the posterior fragment and the ankle dislocation and the size of the posterior malleolus and syndesmosis stability (p = 0.328). Age over 61 years, BMI > 40, ASA > 1, type C fracture, and fracture dislocation were considered as negative prognostic fractures.

CONCLUSIONS

Surgical treatment for trimalleolar fractures needs accurate preoperative planning. Age over 61 years, BMI > 40, ASA > 1, type C fracture, and fracture dislocation were considered as negative prognostic fractures.

In defence of the posterior malleolus

The posterior malleolus of the ankle is the object of increasing attention, with considerable enthusiasm for CT scanning and surgical fixation, as expressed in a recent annotation in The Bone & Joint Journal. Undoubtedly, fractures with a large posterior malleolar fragment that allow posterior talar subluxation from the mortise are served better by fixation. However, in all other situations, the existing literature does not support this widespread change in practice. The available biomechanical evidence shows that the posterior malleolus has little part to play in the stability or contact stresses of the ankle joint. Radiographic studies have not shown that CT scanning offers helpful information on pathoanatomical classification, case selection, or prognosis, or that scanning improves the likelihood of an adequate surgical reduction. Clinical studies have not shown any improvement in patient outcome after surgical fixation, and have confirmed that the inevitable consequence of increased intervention is an increased rate of complications. A careful and thoughtful evaluation of indications, risks, and benefits of this fashionable concept is required to ensure that we are deploying valuable resources with efficacy, and that we do no harm.

Cite this article: Bone Joint J 2018;100-B:566–9.

Posterior malleolus fractures

The posterior malleolus component of a fracture of the ankle is important, yet often overlooked. Pre-operative CT scans to identify and classify the pattern of the fracture are not used enough. Posterior malleolus fractures are not difficult to fix. After reduction and fixation of the posterior malleolus, the articular surface of the tibia is restored; the fibula is out to length; the syndesmosis is more stable and the patient can rehabilitate faster. There is therefore considerable merit in fixing most posterior malleolus fractures. An early post-operative CT scan to ensure that accurate reduction has been achieved should also be considered.

Cite this article: Bone Joint J 2017;99-B:1413–19.