A systematic review of posterior pilon variant fractures

Posterior pilon variant ankle fractures (PPVF) are a unique subtype of posterior malleolar fractures which have been a source of controversy and confusion in recent years. There has not been a thorough literature review previously written on the topic. Database searches of PubMed and Embase were conducted from inception until June 2023. The key words included "pilon variant," "posterior pilon variant," and "posterior pilon" fractures. Outcomes were evaluated by union time, rates of delayed union, nonunion, malunion, and complication. A total of 15 articles relevant to surgical repair of pilon variant fractures were included in the literature review. The unique mechanism of injury has been reported to involve both rotational and axial forces, leading to involvement of the posterior and medial aspects of the distal tibia. Pilon variant fractures can be suspected by several characteristics on radiographs and have a high confirmation rate via CT images. Multiple systems have been proposed to classify this fracture pattern, but there is no consensus on the ideal classification system. Surgically, direct fixation has shown better short-term clinical outcomes versus indirect fixation or no fixation. PPVF have a distinct fracture pattern involving the posterior and medial columns of the distal tibial plafond, and results from a mechanism intermediate to rotational and axial forces. These fractures are more severe than tri-malleolar fractures due to increased rates of articular impaction and incongruity. Future classification systems should focus on joint surface area and the tibial pilon column involved to avoid confusion with less severe posterior malleolar fractures.

Comparison of plate versus screw internal fixation in the treatment of posterior malleolar fracture: A systematic review and meta-analysis

BACKGROUND

Treatment of posterior malleolar fracture with plate or screw fixation is still controversial. Plate fixation is considered to have better stability but more soft tissue damage; screw fixation is less invasive and may yields lesser blood loss and surgery time. We conducted this meta-analysis to explore intraoperative and postoperative efficacy between plate and screw fixation in posterior malleolar fractured patients.

METHODS

PubMed, Cochrane, Embase, Scopus and Chinese National Knowledge Infrastructure databases were searched in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. Random-effects model and 95% confidence intervals was used. The outcomes of interest were surgery time, blood loss, length of hospital stay, American Orthopedic Foot and Ankle Score (AOFAS), bone healing time, full weight bearing time, off bed ambulation time, Visual Analogue Scale (VAS), complication rate, and rate of use of syndesmosis screw etc. RESULTS: One randomized clinical trial and fifty-two retrospective cohort studies with a total of 3757 patients (1956 in screw group and 1801 in plate group) were included in the systematic review. Compared to screw group, plate group yielded significantly longer surgery time, more intraoperative blood loss, but shorter length of hospital stay, better AOFAS, better Baird Jackson score, better AOFAS and Baird Jackson excellent-good rate, shorter bone healing time, shorter time enabling full weight bearing, shorter time enabling off bed ambulation, lesser postoperative pain, lesser complication rate, lesser loosening rate, lesser malunion rate, and lesser postoperative osteoarthritis.

CONCLUSIONS

Plate fixation is a favorable alternative to screw fixation in posterior malleolar fractured patients. Although plate fixation was at risk of longer surgery time and more blood loss, it provided better postoperative functional outcome, shorter healing, weight bearing and off bed ambulation time and lesser pain compared to screw fixation.

Combined vertical and external rotational force in plantarflexion position produces posterior pilon fracture: A preliminary cadaveric study

BACKGROUND

Posterior pilon fracture is speculated to occur by a combination of rotation and axial load, which makes it different from rotational posterior malleolar fracture or pilon fracture, but is not validated in vitro. The aim of the current study is to investigate the injury mechanisms of posterior pilon fracture on cadaveric specimens.

METHODS

Eighteen cadaveric specimens were mounted to a loading device to undergo solitary vertical loading, solitary external rotational loading, and combined vertical and external rotational loading until failure, in initial position of plantarflexion with or without varus. The fracture characteristics were documented for each specimen.

RESULTS

Vertical loading force combined with external rotation force diversified the fracture types resulting in pilon fracture, tibial spiral fracture, rotational malleolar fracture, talar fracture or calcaneal fracture. Vertical violence combined with external rotational loading in position of 45° of plantarflexion and 0° of varus produced posterior pilon fracture in specimens No. 13 and 14.

CONCLUSION

Combination of vertical and external rotational force in plantarflexion position on cadaveric specimens produce posterior pilon fracture.

Importance of computed tomography in posterior malleolar fractures: Added information to preoperative X-ray studies

BACKGROUND

Ankle fractures are common lesions of the lower limbs. Approximately 40% of ankle fractures affect the posterior malleolus (PM). Historically, PM osteosynthesis was recommended when PM size in X-ray images was greater than 25% of the joint. Currently, computed tomography (CT) has been gaining traction in the preoperative evaluation of ankle fractures.

AIM

To elucidate the similarity in dimensions and to correlate PM size in X-ray images with the articular surface of the affected tibial plafond in the axial view on CT (AXCT) of a PM fracture.

METHODS

Eighty-one patients (mean age: 39.4 ± 13.5 years) were evaluated (54.3% were male). Two independent examiners measured PM size in profile X-ray images (PMXR) and sagittal CT (SAGCT) slices. The correlation of the measurements between the examiners and the difference in the PM fragment sizes between the two images were compared. Next, the PM size in PMXR was compared with the surface of the tibial plafond involved in the fracture in AXCT according to the Haraguchi classification.

RESULTS

The correlation rates between the examiners were 0.93 and 0.94 for PMXR and SAGCT, respectively (P < 0.001). Fragments were 2.12% larger in SAGCT than in PMXR (P = 0.018). In PMXR, there were 56 cases < 25% and 25 cases ≥ 25%. When PMXR was < 25%, AXCT corresponded to 10.13% of the tibial plafond. When PMXR was ≥ 25%, AXCT was 24.52% (P < 0.001). According to the Haraguchi classification, fracture types I and II had similar PMXR measurements that were greater than those of type III. When analyzing AXCT, a significant difference was found between the three types, with II > I > III (P < 0.001).

CONCLUSION

PM fractures show different sizes using X-ray or CT images. CT showed a larger PM in the sagittal plane and allowed the visualization of the real dimensions of the tibial plafond surface.

[Comparison of posterolateral approach and combined approach in treatment of Mason type 2B posterior malleolar fracture]

Objective

To compare the effectiveness between the posterolateral approach and the posterolateral combined posteromedial approaches in the treatment of Mason type 2B posterior malleolar fracture.

Methods

A retrospective analysis was performed on the clinical data of 79 patients with posterior ankle fracture who met the selection criteria between January 2015 and January 2022. There were 62 cases of Mason 2B Pilon subtype and 17 cases of avulsion subtype. Among Mason 2B Pilon subtype patients, 35 were treated with posterolateral approach (group A), 27 patients were treated with combined approach (group B). There was no significant difference in gender, age, injured side, cause of injury, time from injury to operation, preoperative hospital stay, preoperative visualanalogue scale (VAS) score, and intraoperative internal fixation between the two groups ( P>0.05). All patients with Mason 2B avulsion subtype were treated by posterolateral approach, including 7 males and 10 females, aged from 25 to 68 years, with an average of 46.1 years. The operation time, intraoperative blood loss, postoperative hospital stay, and complications were recorded. The reduction quality was evaluated by Ovadia deals radiographic score, and the ankle function and pain were evaluated by VAS score, American Orthopaedic Foot and Ankle Society (AOFAS) score, and ankle range of motion.

Results

Mason 2B Pilon subtype: There was no significant difference in operation time, intraoperative blood loss, postoperative hospital stay, and follow-up time between the two groups ( P>0.05). The radiological evaluation of Ovadia deals in group A was significantly worse than that in group B ( P<0.05). The VAS score in the two groups significantly improved at each time point after operation, and the VAS score and AOFAS score further improved with the extension of time after operation, and the differences were significant ( P<0.05). Except that the AOFAS score of group A was significantly lower than that of group B at last follow-up ( P<0.05), there was no significant difference in VAS score and AOFAS score between the two groups at other time points ( P>0.05). At last follow-up, the ankle range of motion in group A was significantly less than that in group B ( P<0.05). There was no significant difference in the incidence of sural nerve injury, deep tissue infection, limitation of toe movement, and traumatic ankle arthritis between the two groups ( P>0.05). Mason 2B avulsion subtype: The operation time was (119.47±20.61) minutes and the intraoperative blood loss was 50 (35, 55) mL. Seventeen patients were followed up 13-25 months, with an average of 18 months. The Ovadia deals score was excellent in 10 cases, good in 6 cases, and poor in 1 case at 1 week after operation, and the excellent and good rate was 94.1%. All fractures healed in 8-18 weeks with an average of 12.35 weeks. There were 1 case of sural nerve injury and 3 cases of traumatic ankle arthritis after operation. No deep tissue infection or limitation of toe movement occurred. The VAS score decreased significantly and AOFAS score increased significantly with time, and the differences were significant between different time points before and after operation ( P<0.05). The ankle range of motion at last follow-up was (56.71±2.47)°.

Conclusion

Compared with the posterolateral approach, the combined approach is a better choice for the treatment of Mason 2B Pilon subtype. If the posteromedial bone block does not affect the reduction of the medial malleolus, the posterolateral approach can achieve good effectiveness for Mason 2B avulsion subtype.

Syndesmosis dislocation and ankle ligament stress in the posterior malleolus fracture fixated - "in vitro analysis"

PURPOSE

The objectives of this study were to compare syndesmosis dislocation and ankle ligament stress after the fixation of the posterior malleolus fracture (PMF) with four different techniques by Finite Element Analysis (FEM).

METHODS

Four internal fixation techniques used for fixation of PMF were assessed by FEM: posterior one-third tubular 3.5 mm buttress plate (PP) with one screw (PP 1 screw), PP with two screws (PP 2 screws), two cannulated 3.5 mm lag screws in the anteroposterior (AP) direction (AP lag screws), and two posteroanterior (PA) cannulated 3.5 mm lag screws (PA lag screws). PMF with 30% fragment size was simulated through computational processing reconstructed from computed tomography (CT). The simulated loads of 700 N and 1200 N were applied to the proximal tibial end. The FEM evaluated the syndesmosis dislocation (mm) and stress values of the posterior tibiofibular ligament (PTFL) (in Kpa) and deltoid ligament (in Kpa) in the four mentioned subgroups.

RESULTS

We found that with a load of 700 N, syndesmosis dislocation varied from 6.5 to 7.9 mm, being the lowest and greatest for PA lag screw and PP 1 screw, respectively. In all groups was observed a greater dislocation in the syndesmosis at 1200 N of load. We observed that the stress values on the PTFL were lower for AP lag screws and PP 2 screws with 700 N and 1200 N, respectively. For both loads, PP 1 screw presented the greatest stress. Regarding the stress in the deltoid ligament, the AP lag screws presented the lowest stress for 700 N and PP 1 screw for 1200 N. For all fixation techniques, the syndesmosis displacement and ligament stresses were higher when 1200 N were imposed.

CONCLUSION

This study demonstrated that PMF fixed with lag screws presents greater stability in the distal tibiofibular syndesmosis and higher joint loadings promoted greater displacement and ligaments stress, regardless of the fixation technique. Besides, lower stress in the syndesmosis is accompanied by a greater load on the deltoid ligament.

Locking versus nonlocking plates for the treatment of posterior malleolar ankle fractures: A retrospective cohort study and cost analysis

BACKGROUND

We hypothesized that, as posterior malleolar ankle fractures usually present one or two main fragments, the buttress plating principle can be successfully achieved either with conventional nonlocking or anatomic locking posterior tibia plates, and no clinical differences should be found. The aim of this study was to evaluate the outcomes of posterior malleolar ankle (PM) fractures treated with conventional nonlocking (CNP) or anatomic locking plates (ALP), and also to compare both constructs in terms of crude costs.

METHODS

A retrospective cohort study was designed. CNP was used in 22 patients and ALP was used in 11 patients. American Orthopedic Foot and Ankle Society (AOFAS) score was registered at four weeks, 3-6 months, 12 and 24 months to assess all patients' functional status. The primary outcome was ankle and hindfoot AOFAS score at 12 months follow-up visit. All complications, radiographic evaluation and implant construct costs were also registered and compared. The average follow-up was 25.4 (range, 12-42) months.

RESULTS

No significant difference was observed between both cohorts, in terms of AOFAS score and complication rate (P > .05). We found that ALP construct is 17 times more expensive than CNP construct in our institution (P < .001).

CONCLUSION

Anatomic locking posterior tibial plates may be an interesting device when poor bone quality is present or when a true multifragmentary pilon fracture is faced. Anatomic locking posterior tibia plate should not become a regular implant for any PM fracture since equivalent clinical and radiological results were obtained in our study using CNP with a significant reduced cost.

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.

Plate versus screws fixation for the posterior malleolar fragment in trimalleolar ankle fractures

BACKGROUND

The fixation methods of posterior malleolar fracture (PMF) in trimalleolar ankle fractures is still controversial. We aim to compare clinical and radiological outcomes between plate fixation and screws fixation for PMF in trimalleolar ankle fractures.

METHODS

Literature search was performed through PubMed, EMBASE, Cochrane Library and CNKI database from databases inception to May 2022 to identify randomized controlled trial (RCT) and comparative clinical study in English or Chinese. A meta-analysis was performed using RevMan 5.1 software, and systematic review was performed when the data extracted from included studies could not be synthesized.

RESULTS

Two RCTs and six cohort studies were included. The meta-analysis results showed that articular step-off or gap in plate fixation was superior to antero-posterior screws fixation (RR = 0.28; 95%CI: 0.11, 0.76; P = 0.01). there were no significant differences in American Orthopaedic Foot & Ankle Society scores (MD = -0.19; 95%CI: -2.43, 2.05; P = 0.87), arthritis (RR = 1.67; 95%CI: 0.61, 4.55; P = 0.32), infection and total complication (RR = 1.42; 95%CI: 0.89, 2.25; P = 0.14).

CONCLUSION

Plate fixation might have better articular step-off or gap, compared with "A to P" screws fixation for the posterior malleolus in trimalleolar ankle fractures. Screw fixation could achieve shorter surgical time than plate fixation. However, no significant differences were found in AOFAS scores, arthritis, infection, sural nerve injury and total complication during the comparisons.

Posterior malleolus fracture: a mid-term follow-up

BACKGROUND

The treatment of posterior malleolar fractures is changing rapidly, and the evidence base is still catching up. This study aimed to assess the mid-term prognosis of posterior malleolar fractures based on different morphological types and provides evidence for the treatment of posterior malleolar fractures.

METHODS

We retrospectively analyzed the data of inpatients with posterior malleolar fractures from 1 January 2012 to 31 December 2019 at one high-volume tertiary trauma center. Fracture morphology was classified into small-shell fragment, single-fragment (small-fragment and large-fragment) and multifragment (double-fragment and compressive-fragment) by computed tomography according to our previous study. All patients were followed up at an average of 5.06 (range, 2.21-8.70) years. The Olerud-Molander Ankle Score (OMAS), EuroQol-5 Dimensions (EQ-5D) and American Orthopedic Foot and Ankle Society (AOFAS) score were recorded.

RESULTS

Seventy-nine patients were included, and 7 patients were classified into the small-shell group, 52 patients into the single-fragment group and 20 patients into the multifragment group. Of all the patients, the average OMAS, EQ-5D and AOFAS scores were 85.9, 82.8 and 92.5, respectively. In the single-fragment group, patients who underwent surgical fixation in the posterior malleolus had significantly better scores (P = 0.037, 0.033 and 0.027). Among the patients with small fragments, the surgical fixation group also had higher OMAS (93.1 ± 7.5 vs. 83.5 ± 19.5, P = 0.042) and AOFAS scores (98.1 ± 3.1 vs. 91.0 ± 14.1, P = 0.028). The mean OMAS, EQ-5D and AOFAS scores were 85.5, 85.7 and 91.7, respectively, in patients with multiple fragments who underwent surgical fixation.

CONCLUSION

This study shows that in fractures with a single fragment, surgical fixation of the posterior malleolar fragment led to a better prognosis in the midterm. All single fragments should be fixed regardless of size. Fixation of the posterior region in all single- and multi-fragments in posterior malleolar fractures led to satisfactory outcomes.

LEVEL OF EVIDENCE

Level III, follow-up study.

Prediction of distal tibial articular extension in tibial shaft fractures: both posterior malleolar fracture and non posterior malleolar fracture intra-articular extension

BACKGROUND

Multiple authors have highlighted the increased incidence of occult posterior malleolar fractures (PMFs) with spiral tibial shaft fractures, although other reported associated risks of intra-articular extension have been limited. The aim of our study is to investigate both PMFs and non-PMFs intra-articular extensions associated with tibial diaphyseal fractures to try to determine any predictive factors.

METHODS

We undertook a retrospective review of a prospectively collected database. The inclusion criteria for this study were any patient who had sustained a diaphyseal tibial fracture, who had undergone surgery during the study period and who had also undergone a CT scan in addition to plain radiographs. The study time period for this study was between 01/01/2013 and 9/11/2021.

RESULTS

Out of 764 diaphyseal fractures identified, 442 met the inclusion criteria. A total of 107 patients had PMF extensions (24.21%), and a further 128 patients (28.96%) had intra-articular extensions that were not PMF's. On multivariate analysis, spiral tibial fracture subtypes of the AO/OTA classification (OR 4.18, p < 0.001) and medial direction of tibial spiral from proximal to distal (OR 4.38, p < 0.001) were both significantly associated with PMF. Regarding intra-articular fractures, multivariate analysis showed significant associations with non-spiral (OR 4.83, p < 0.001) and distal (OR 15.32, p < 0.001) tibial fractures and fibular fractures that were oblique (OR 2.01, p = 0.019) and at the same level as tibia fracture (OR 1.83, p = 0.045) or no fracture of the fibular (OR 7.02, p < 0.001).

CONCLUSION

In our study, distal tibial articular extension occurs in almost half of tibial shaft fractures. There are very few fracture patterns that are not associated with some type of intra-articular extension, and therefore, a low threshold for preoperative CT should be maintained.

LEVEL OF EVIDENCE: 4

Computed tomography-based classifications of posterior malleolar fractures and their inter- and intraobserver reliability: a comparison of the Haraguchi, Bartoníček/Rammelt, and Mason classifications

INTRODUCTION

Complex ankle fractures often include fractures of the posterior malleolus. The most clinically relevant posterior malleolus fracture classifications are computed tomography (CT) based. These classifications aim to enable clear communication and help develop treatment strategies. This study investigates the inter- and intraobserver reliability of the Haraguchi, Bartoníček/Rammelt and Mason posterior malleolar fracture classifications.

MATERIALS AND METHODS

CT scans of 113 patients with a mean age of 56.2 (SD ± 17.8) years and fractures involving the posterior malleolus were analyzed twice by 4 observers with different levels of training. The posterior malleolar fractures were classified according to Haraguchi et al., Bartoníček/Rammelt et al. and Mason et al. The intraobserver and interobserver reliabilities were determined by calculating Cohen's and Fleiss' kappa values.

RESULTS

We found substantial multi-rater interobserver agreement for all three classifications. The Haraguchi classification 0.799 (CI 0.744-0.855) showed the highest agreement, followed by the Bartoníček/Rammelt 0.744 (0.695-0.793) and Mason 0.717 (CI 0.666-0.768) classifications. Subgroup analyses showed substantial to perfect agreement for the Haraguchi and substantial agreement for the Bartoníček/Rammelt and Mason classifications independent of observer expertise. The intraobserver reliability was perfect for three and substantial for one of the observers. However, the classifications have certain pitfalls and do not consider the number of fragments, articular surface impressions, or intercalary fragments.

CONCLUSION

All classifications show substantial, if not perfect inter- and intraobserver reliabilities independent of observer level of expertise.

Arthroscopic handlebar technique for the treatment of posterior malleolar fractures

Treating posterior malleolar fractures of the ankle remains a challenge. The arthroscopic handlebar technique is our novel surgical method used for reduction and fixation of posterior malleolar fractures and involves the restoration of posterior malleolar fractures under anterior arthroscopic guidance and the use of Kirschner wires that penetrates the fractured posterior malleolus. Arthroscopy enables visualization of the intra-articular fracture of the posterior malleolus, and a handlebar reduction bar is used to control the fractured posterior malleolus. The arthroscopic handlebar technique is a promising procedure for reduction and internal fixation of the posterior malleolar fractures.

Fracture obliquity angle and distance from plafond: novel radiographic predictors of posterior malleolar involvement in tibial shaft fractures

BACKGROUND

The purpose of this study was to identify specific radiographic parameters that are predictive of associated PM fractures in TSFs.

METHODS

All TSFs presenting over a 6-year period were identified. A review of plain radiographs and CT scans included: identification of an isolated PM fracture, AO/OTA classification, measurements of the fracture obliquity angle (FOA), absolute and relative distance from distal extent of fracture to plafond (DFP and DFP%), and presence and level of associated fibular fractures. Patients with and without PM fractures were compared. Multivariate logistic regression determined independent correlates of PM fractures and cutoff values for FOA and DFP%.

RESULTS

A total of 405 TSFs in 397 patients were identified, and 94 TSFs (23.2%) had an associated PM fracture. The majority (85.1%) of TSFs with PM fractures were AO/OTA type 42-A1, 42-B1 or 42-C1 (p < 0.001). The mean FOA was 60.9 ± 12.1° in the PM group versus 40.8 ± 18.9° in the non-PM group (p < 0.001). The mean DFP was 5.9 ± 2.7 cm in the PM group versus 11.9 ± 7.9 cm in the non-PM group (p < 0.001). Multivariate regression demonstrated that AO/OTA classification type 42-A1, 42-B1 or 42-C1 (OR 4.7 [95% CI 2.4-9.8]; p < 0.001), FOA greater than 45° (OR 4.4 [95% CI 1.9-10.9]; p = 0.001) and fracture extension to the distal third of the tibia (DFP% < 33%; OR 18.3 [95% CI 3.8-330.4]; p = 0.005) were independent correlates of PMs fractures regardless of mechanism of injury or fibula fracture presence or location (AUROC 0.83 [95% CI 0.80-0.87]). Separate multivariate regression showed for every 1° increase in FOA, PM fracture odds increase 6% per degree and for every 1 cm increase in DFP odds of PM fracture decreased by 15%.

CONCLUSIONS

Spiral fractures (simple, wedge or complex), fracture angles greater than 45° and extension into the distal 1/3 of the tibial shaft are independent predictors of PM fractures in TSFs regardless of mechanism of injury.

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.

Biomechanical comparison of four different posterior malleolus fixation techniques: A finite element analysis

PURPOSE

The objective of this study was to compare the biomechanical behavior of four fixation methods for posterior malleolar fracture (PMF) by finite element analysis (FEM).

METHODS

Four internal fixation techniques used for fixation of PMF were assessed by FEM - a computational study: posterior one-third tubular 3.5 mm buttress plate (PP) with one screw (PP 1 screw), PP with two screws (PP 2 screws), two cannulated 3.5 mm lag screws in the antero-posterior (AP) direction (AP lag screws), and two postero-anterior (PA) cannulated 3.5 mm lag screws (PA lag screws). PMF with 30% and 50% fragment sizes were simulated through computational processing reconstructed from computed tomography (CT). The simulated loads of 700 N and 1500 N were applied to the proximal tibial end. The FEM evaluated the total and localized displacements of the PMF. For the analysis of stresses, the variables maximum principal (traction) and minimum principal (compression) were used. For the metallic implants, the equivalent von Mises stress (VMS) was used.

RESULTS

PA lag screw showed the lowest values for total and localized displacement, minimum and maximum total stress, and VMS in both physiological conditions and sizes of posterior malleolus involvement. The localized displacement was statistically lower for lag screws compared to PP techniques at 700 N (p < 0.05) and 1200 N (p < 0.05). The maximum total stress was statistically lower for PA lag screws compared to PP 1 fixation with 700 N (p = 0.03) and 1200 N (p = 0.039).

CONCLUSION

PA lag screws yield better results in terms of total and localized displacement, minimum and maximum total stress, and VMS in both physiological conditions and sizes of posterior malleolus involvement. These results demonstrate that PA lag screws are biomechanically the most efficient technique for the fixation of PMF.

Pre-and postoperative factors associated with functional outcomes in patients with posterior malleolar fractures

INTRODUCTION

Recent studies on posterior malleolar fractures mainly focus on the reduction quality and fixation of the posterior fragment since it contributes to ankle stability and articular congruency. However, the association of pre-and postoperative factors considering the whole ankle joint in postoperative functional outcomes remains unclear. Therefore, this study aimed to examine the association between pre-and postoperative variables for postoperative functional outcomes in patients with posterior malleolar fragments (classified as Haraguchi type I or II) and considered the association between reduction and fixation for small posterior malleolar fragments of less than 25% of the intra-articular surface.

METHODS

This multicenter retrospective cohort study included 110 adult patients who underwent internal fixation for ankle fractures with posterior malleolar fragments. The primary outcome was the American Orthopaedic Foot and Ankle Society (AOFAS) score 12-months postoperatively. As pre-and postoperative variables, the preoperative demographic data, radiographic findings, operative method, postoperative radiographic findings, and complications were evaluated. In addition, univariable and multivariable logistic regression analyses were conducted to examine the association between pre-and postoperative variables and AOFAS scores.

RESULTS

Twenty-four (21.8%) cases had postoperative complications. Univariate analysis showed that age was significantly according to AOFAS score-stratified groups in patients with Haraguchi type II fractures. Multivariable logistic regression analysis using bootstrapping in the Haraguchi type II group showed that postoperative complications were significantly associated with low AOFAS scores, indicating poor functionality. In both fracture types, postoperative complications had the highest odds ratio among the explanatory variables. In patients with small posterior malleolar fragments, fragment reduction, fixation, and ankle stability were not associated with AOFAS scores.

CONCLUSIONS

Our results suggest that postoperative complications were associated with AOFAS scores at postoperative 12 months in patients with ankle fractures with posterior malleolar fragments. In patients with small posterior malleolar fragments, reduction and fixation were not associated with AOFAS scores. Therefore, clinical decisions for posterior fragment fixation should be made based on the possible risk of complications related to the surgical procedures in addition to the posterior malleolar fragment size.

Marginal impaction associated with posterior malleolar fracture in rotational ankle injury

AIM

This study aimed to introduce the circle drawing method for the evaluation of marginal impaction associated with posterior malleolar fractures (PMFs) on computed tomography (CT) images and evaluate the marginal impaction based on PMF patterns (Bartonícek classification) in rotational ankle fractures.

METHODS

From January 2014 to December 2019, A total of 299 patients were reviewed retrospectively. The circle drawing method consists of matching the articular surface of the intact tibial plafond with a best-fitted circle on the sagittal CT image. The mismatch gap between the circle and the articular surface indicates the presence of marginal impaction. To validate the circle drawing method, we assessed CT images of 60 ankles without fracture at the medial, central, and lateral parts using the new method.

RESULTS

Based on the review of the preoperative CT scan, 153 out of 299 patients (51.2%) were identified as having PMFs. Among them, 57 patients (37.3%) had marginal impaction associated with PMFs. For small posterolateral type 2 fractures, 58% of patients (47/81) had marginal impaction, and its incidence was most frequent among all types (P<.01). For posteromedial extended type 3 fractures, 27% of patients (8/30) had marginal impaction. Extraincisural type 1 and large posterolateral triangular type 4 fractures were rarely associated with marginal impaction. Among the 180 zones of 60 ankles without fracture, 171 zones (95%) were perfectly fitted to a best-fitted circle.

CONCLUSIONS

The marginal impaction associated with PMFs is often observed in rotational ankle fractures, particularly in small posterolateral and posteromedial extended fractures.

Incidence and risk factors of (Occult) posterior malleolar fractures in patients with spiral distal tibial fractures: Reexamination and analysis

OBJECTIVE

To evaluate the incidence and risk factors for posterior malleolar fractures (PMFs) in patients with spiral distal tibial fractures (SDTFs).

METHODS

In a retrospective study, 248 adults with SDTFs who underwent treatment were enrolled between November 2017 and May 2020. In a prospective study, we recruited 113 consecutive, skeletally mature patients with SDTFs who were identified from the trauma clinic of our hospital between June 2020 and May 2021. Radiographs and CT scans of the ankle region on the affected side were obtained to determine the presence of PMFs. If the CT scan was negative, additional MRI examination of the ankle was performed as a supplementary protocol in the prospective study. Univariate analysis and multivariate analysis were conducted to analyze the risk factors.

RESULTS

In the retrospective study, the incidence of PMFs associated with simple SDTFs was 74.0% (105/142), which was significantly lower than 90.8% (69/76) in the prospective study. Independent predictors of PMFs in patients with simple SDTFs identified by multivariate analysis in the retrospective study were age (OR = 1.07; P = 0.001) and external rotation of the proximal tibia (OR = 3.36; P = 0.027) and those in the prospective study were osteoporosis (OR = 0.04; P = 0.007) and spiral fibula fractures (OR = 16.05; P = 0.046).

CONCLUSION

This study reexamined the high incidence of concurrent PMFs. Additionally, ankle radiographs and CT scans were recommended for all simple SDTF patients. For simple SDTF patients with negative CT scans, especially those caused by external rotation of the proximal tibia, combined with nonosteoporotic or spiral fibula fractures, additional MRI examinations are recommended.

Predisposing factors for chronic syndesmotic instability following syndesmotic fixation in ankle fracture: Minimum 5-year follow-up outcomes

BACKGROUND

This study aimed to identify risk factors for chronic syndesmotic instability following syndesmotic fixation.

METHODS

We performed a retrospective review of consecutive patients who had sustained ankle fractures requiring syndesmotic fixation. Patients available for a minimum 5 years of follow-up were classified into 2 groups according to the presence of syndesmotic instability. Statistical binary logistic regression analyses were performed to investigate the significance of various risk factors. Functional outcomes were assessed using the FAOS.

RESULTS

In total, 166 patients who met the study inclusion criteria underwent analysis. The overall postoperative instability rate was 20.5%, which was significantly affected due to BMI (p = 0.018; OR 6.72), and concomitant posterior malleolar fracture (p = 0.032, OR 2.77). The mean scores in the syndesmotic instability (SI) group were significantly lower than those in the no syndesmotic instability (NSI) group (p = 0.021).

CONCLUSIONS

Obesity and concomitant posterior malleolar fracture were significant risk factors for postoperative syndesmotic instability.

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

BACKGROUND AND PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Untreated small posterior fragment of ankle fracture with early removal of syndesmotic screw is associated with recurrent syndesmotic instability

INTRODUCTION

This retrospective study aimed to report outcomes of fixation of bi-malleolar or tri-malleolar fractures combined with syndesmotic injury with or without posterior malleolar fracture (PMF), and to ascertain whether syndesmotic screw removal at 6 to 8 weeks or 3 months postoperatively is more beneficial.

METHODS

We retrospectively reviewed patients who received open reduction and internal fixation for bi-malleolar (without PMF) or tri-malleolar ankle fracture (with PMF) with syndesmotic injury between January 2013 and December 2017 with at least 24 months of postoperative follow-up. All patients suffered syndesmotic instabilities and were treated using a syndesmotic screw without PMF fixation. Patients with bi-malleolar fracture with syndesmotic screw removal at 6 to 8 weeks postoperatively were included in Group I, tri-malleolar fracture with syndesmotic screw removal at 6 to 8 weeks in Group II, and tri-malleolar fracture with syndesmotic screw removal at 3 months in Group III. Demographic data, clinical and radiographic outcomes were analyzed.

RESULTS

A total of 113 patients were included (Group I, n=47; Group II, n=43; Group III, n=23). Average size of PMF was 14% in patients with tri-malleolar fractures (Groups II and III). No significant difference in ankle functional outcome among groups was observed. The recurrence rate of syndesmotic instability was 10.6% in Group I, 20.9% in Group II, and 8.7% in Group III. Although the difference in recurrence rates of syndesmotic instability among three groups was not statistically significant (P=0.264), Group II showed more interval change in tibiofibular clear space between initial postoperative radiographs and last follow-up radiographs (P=0.028) compared to the other two groups. Fracture union was achieved in all patients without screw breakage.

CONCLUSION

We suggest that the better timing for syndesmotic screw removal is 3 months, instead of 6 to 8 weeks postoperatively, to reduce the risk of recurrence of syndesmotic instability for tri-malleolar fracture without posterior fragment fixation.

LEVEL OF EVIDENCE

Level III- Case-control study.

Comparison of the efficacy of posterior-anterior screws, anterior-posterior screws and a posterior-anterior plate in the fixation of posterior malleolar fractures with a fragment size of ≥ 15 and < 15

Background

Different fixation methods have been used to treat posterior malleolar fractures (PMFs), but the clinical efficacy of different fixation methods in the treatment of PMF with different fragmentation has rarely been reported. The purpose of this study was to investigate the efficacy of posterior-anterior (PA), anterior-posterior (AP) screws and PA plate in the fixation of PMFs with a fragment size of ≥15 and < 15%.

Methods

This is a retrospective study of the clinical data of 243 patients with a unilateral ankle fracture involving the posterior malleolar ankle fracture. All patients were divided into two groups based on their fragment size, ≥15% (n = 136) and < 15% (n = 107). After reduction of PMF under direct vision via a posterolateral approach, posterior-anterior (PA), anterior-posterior (AP) screws and PA plate were used for fixation of PMF in the two groups. Briefly, for fixation of PMF with PA screw, two to three 3.5-mm (Depuy Synthes, Switzerland) cannulated screws were placed from the posterior to anterior direction; for fixation with PA plate, a 3.5-mm reconstruction plate (Depuy Synthes, Switzerland) was placed from the posterior to anterior direction, and for fixation of PMF with an AP screw, two to three 3.5-mm screws were placed from the anterior to posterior direction. All patients were followed up at 1, 3, 6, and 12 months after surgery and thereafter at 6-month intervals. The primary outcomes were AOFAS and ROM, which were recorded at the final follow-up.

Results

The average follow-up time for all patients was 18.9 months (range 12–36 months), and all fractures healed. In fragment size ≥15% group, the average AOFAS score of patients treated with PA, AP screws and posterior plate were 91.5, 91.8, and 90.8, respectively, and the average limited ankle-dorsiflexion ROM was 5.0 °, 5.4 ° and 5.6°, respectively, at the last follow-up, there was no significant difference between the three fixation methods in terms of AOFAS scores and ankle ROM (P > 0.05). In fragment size < 15% group, the average AOFAS score of patients treated with PA, AP screws and posterior plate were 92.3, 91.9, and 84.1, respectively, the average limited ankle-dorsiflexion ROM were 5.1 °, 4.7 °, and 6.3 °, respectively, at the last follow-up. There were statistically significant differences in AOFAS scores and ankle ROM between posterior plate fixation and PA, AP screw fixation (P < 0.05); while no significant difference was found between PA and AP screw fixation (P > 0.05).

Conclusion

For PMFs with fragment size ≥15%, there was no significant difference in the outcomes between the three fixation methods. For PMF with fragmentation < 15%, the PA and AP screws both provided good fixation.

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.

Preoperative planning and surgical technique for optimizing internal fixation of posterior malleolar fractures: CT versus standard radiographs

BACKGROUND

A proper reduction and internal fixation of posterior malleolar fractures can be challenging, as intraoperative fluoroscopy often underestimates the extent of the fracture. Our aim was to assess the value of a modified classification system for posterior malleolar fractures, which is based on computed tomography (CT) images, optimizing screw trajectory during fluoroscopic-guided surgery, and to compare it to the Lauge-Hansen classification system to the CT-based classification.

METHODS

A retrospective review of all ankle fracture operations from January 2014 to December 2016 was performed. Fractures were included if a CT scan was performed within 1 week of the surgery, and the posterior malleolar fragment occupied one third or more of the antero-posterior talar surface or jeopardize the ankle stability. Eighty-five adult ankle fractures with posterior malleolar fragments were included in this study. Fractures were categorized into one of three types, namely "postero-lateral," "postero-medial," or "postero-central," according to the location of the fracture fragment on axial CT image. An optimal trajectory angle for a single-lag screw fixation was measured on the CT cut between a central antero-posterior line and the line intersecting the posterior fragment perpendicular to the major fracture line. Mean trajectory angles were calculated for each fracture type. Fractures were also categorized according to the Lauge-Hansen system.

RESULTS

The mean trajectory angle was 21° lateral for "postero-lateral" fragments, 7° lateral for "postero-central" fragments, and 28° medial for "postero-medial" fragments (p < 0.01 for comparisons among the groups). The range of trajectory angles within each group was about 10°, as compared to about 20° within each Lauge-Hansen type. There were no differences in trajectory angle among the Lauge-Hansen groups (p > 0.05 for all comparisons).

CONCLUSIONS

There are 3 distinct anatomic subgroups of posterior malleolar fragments, each with an ideal screw trajectory that needs to be used in order to achieve an optimal reduction and fixation.

Posterior pilon fracture: Epidemiology and surgical technique

OBJECTIVES

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

DESIGN

Consecutive case series.

SETTING

Level I trauma center.

PATIENTS/PARTICIPANTS

Twenty-five patients with posterior pilon fracture.

INTERVENTION

Posterior pilon fracture open reduction and internal fixation.

MAIN OUTCOME MEASUREMENTS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Therapeutic level IV.

Pathoanatomy of Maisonneuve fracture based on radiologic and CT examination

INTRODUCTION

Although Maisonneuve fracture (MF) is a well-known type of ankle fracture-dislocation, there is still a lack of information about the epidemiology and the extent of all associated injuries. The aim of study is to describe MF pathoanatomy on the basis of radiographs, CT scans and intraoperative findings.

MATERIALS AND METHODS

The study comprised 54 adult patients. MF was defined as an ankle fracture-dislocation with a fracture of the fibula in its proximal quarter. Ankle radiographs and lower leg radiographs were obtained in all patients. Computed tomography (CT) examination was performed in 43 patients, of these in 34 patients in combination with 3D CT reconstructions. A total of 51 patients were treated operatively, and in 38 of these an open procedure was performed.

RESULTS

The fibular fracture-fibular head was involved in four cases, and the subcapital region of the proximal quarter of the fibula was affected in 50 cases. Fractures of the posterior malleolus were identified in 43 of 54 patients (80%). Injury to the deltoid ligament was recorded in 27 cases (50%), a fracture of the medial malleolus in 20 cases (37%) and medial structures were intact in 7 cases (13%). Position fibula in fibular notch-in 9 cases the position changed only minimally, in 11 cases the space between the tibia and the fibula was larger than 2 mm, in 20 cases widening of the tibiofibular space was associated with external rotation of the fibula, in 2 cases fibula was trapped behind the posterior tibial tubercle and in 1 case it was associated with a complete tibiofibular diastasis.

CONCLUSION

MF is a variable injury, always associated with rupture of the anterior and interosseous tibiofibular ligaments. CT examination should be employed widely in MF, and MRI should be considered under special circumstances.

Persistent postoperative step-off of the posterior malleolus leads to higher incidence of post-traumatic osteoarthritis in trimalleolar fractures

BACKGROUND

Traditionally, size of the posterior fragment is considered the most important indicator for fixation in trimalleolar fractures. It remains unclear which factors contribute to worse functional and radiological outcome. This study was designed to determine predictors for the development of posttraumatic osteoarthritis and worse functional outcome in trimalleolar fractures.

METHODS

This retrospective cohort study evaluated outcomes of 169 patients with a trimalleolar fracture treated between 1996 and 2013 in a level-1 trauma hospital in the Netherlands after a mean follow-up of 6.3 (range 2.4 to 15.9) years. The average fragment size was 17%. Twenty patients had a posterior fragment smaller than 5% of the intra-articular surface, 119 patients a fragment of 5-25% and 30 patients a posterior fragment larger than 25%. In total, 39 patients (23%) underwent fixation of the posterior fragment.

RESULTS

Clinical union was achieved in all 169 patients. The median AOFAS score after follow-up was 93 (interquartile range 76-100) and the median AAOS score was 92 (interquartile range 81-98). A persistent postoperative step-off larger than 1 mm was found in 65 patients (39%) and osteoarthritis was present in 49 patients (30%). Higher age and postoperative step-off > 1 mm were independent, significant risk factors for the development of osteoarthritis. Osteoarthritis and BMI were independent, significant risk factors for worse functional outcome.

CONCLUSION

It is advisable to correct intra-articular step-off of intraarticular posterior malleolar fragments to reduce the risk of developing osteoarthritis and, consequently, the risk of worse functional outcome after long-term follow-up.

LEVEL OF EVIDENCE

Level IIB.

Pre-operative radiographic findings predicting concomitant posterior malleolar fractures in tibial shaft fractures: a comparative retrospective study

Background

A concomitant tibial shaft and posterior malleolar fracture is a type of regular compound fracture. The associated posterior malleolar fractures are mostly occult fractures, which often do not show a fracture line on ordinary films, and thus lead to a high rate of misdiagnosis. The aim of the present study was to investigate factors helpful for the pre-operative detection of concomitant posterior ankle fractures using the ipsilateral radiographic tibia and fibula shaft fracture characteristics.

Methods

One hundred eleven adult patients with tibial shaft fractures were selected using inclusion and exclusion criteria. Pre-operative ankle radiographs and computed tomography (CT) scans were obtained for all patients, and clinical data, including age and gender, were collected. Patients were divided into two groups (posterior malleolar fracture and no posterior malleolar fracture groups). Fracture height, fracture length, fracture shape, and Haraguchi type of posterior malleolar fracture were measured on radiographs and CT images, and were compared between the two groups. Multiple logistic regression analysis was performed to identify the factors that significantly contributed to concomitant posterior malleolar fractures. Receiver operating characteristic curves were calculated, and cut-off values were used to predict posterior malleolar fractures on pre-operative imaging measurements.

Results

Of the 111 patients with tibial shaft fractures, 42 (37.8%) had a concurrent posterior malleolar fracture. Age, gender and affected side were not significantly different, but tibial fracture location, fracture length, and fibular and tibial fracture shape were significantly different between the two groups. In the multiple logistic analysis, tibial fracture location, fracture length, and tibial fracture shape were shown to be significant factors contributing to posterior malleolar fractures. Receiver operating characteristic curves showed that the status of tibial shaft fractures is closely related to the associated posterior malleolar fracture.

Conclusion

Ipsilateral posterior ankle fractures are commonly associated with tibial shaft fractures, especially spiral-type injuries. An analysis of the imaging features of such fractures and evaluation of the diagnostic value of various methods can provide imaging basics for the development of accurate and appropriate treatment options.

Biomechanical efficacy of AP, PA lag screws and posterior plating for fixation of posterior malleolar fractures: a three dimensional finite element study

Background

Clinically there are different fixation methods used for fixation of the posterior malleolar fractures (PMF), but the best treatment modality is still not clear. Few studies have concentrated on this issue, least of all using a biomechanical comparison. The purpose of this study was to carry out a computational comparative biomechanics of three different commonly used fixation constructs for the fixation of PMF by finite element analysis (FEA).

Methods

Computed tomography (CT) images were used to reconstruct three dimensional (3D) model of the tibia. Computer aided design (CAD) software was used to design 3D models of PMF. Finally, 3D models of PMF fixed with two antero-posterior (AP) lag screws, two postero-anterior (PA) lag screws and posterior plate were simulated through computational processing. Simulated loads of 500 N, 1000 N and 1500 N were applied to the PMF and proximal ends of the models were fixed in all degrees of freedom. Output results representing the model von Mises stress, relative fracture micro-motion and vertical displacement of the fracture fragment were analyzed.

Results

The mean vertical displacement value in the posterior plate group (0.52 mm) was lower than AP (0.68 mm) and PA (0.69 mm) lag groups. Statistically significant low amount of the relative micro-motion (P < 0.05) was observed in the posterior plate group.

Conclusions

It was concluded that the posterior plate is biomechanically the most stable fixation method for fixation of PMF.

The isolated posterior malleolar fracture and syndesmotic instability: A case report and review of the literature

INTRODUCTION

Ankle fractures are among the most common type of fractures in the lower extremity. A posterior malleolar fracture is frequently part of a more complex ankle fracture and only in rare cases it occurs as isolated injury. Posterior malleolar fractures often occur with associated injuries, such as a Maisonneuve fracture or with bi- or trimalleolar ligamentous injuries. Knowledge about these associated injuries is essential to prevent missed diagnoses. The aim of this article is to describe the isolated posterior malleolar fracture, the possible associated injuries, the diagnostic work-up and therapeutic consequences.

PRESENTATION OF CASE

We present a case of a 26-year-old male patient who sustained an isolated posterior malleolar fracture with 4.5 years follow-up.

DISCUSSION

Isolated fractures of the posterior malleolus are uncommon injuries. Diagnosis, treatment and outcome can seldom be extracted from large series. However, several cases have been described in literature, which we have summarized.

CONCLUSION

This case report and literature review shows that isolated posterior malleolar fractures might occur as part of a more complex ankle injury, in combination with a fracture of the lower leg or after high energy trauma. Physicians should be aware of these associated injuries. Diagnostic work-up should include X-rays of the knee and lower leg and a CT scan of the ankle. If diagnosed and treated properly, isolated posterior malleolar fractures have a good long-term functional outcome.

Finite element analysis of the three different posterior malleolus fixation strategies in relation to different fracture sizes

PURPOSE

Appropriate fixation method for the posterior malleolar fractures (PMF) according to the fracture size is still not clear. Aim of this study was to evaluate the outcomes of the different fixation methods used for fixation of PMF by finite element analysis (FEA) and to compare the effect of fixation constructs on the size of the fracture computationally.

MATERIALS AND METHODS

Three dimensional model of the tibia was reconstructed from computed tomography (CT) images. PMF of 30%, 40% and 50% fragment sizes were simulated through computational processing. Two antero-posterior (AP) lag screws, two postero-anterior (PA) lag screws and posterior buttress plate were analysed for three different fracture volumes. The simulated loads of 350N and 700N were applied to the proximal tibial end. Models were fixed distally in all degrees of freedom.

RESULTS

In single limb standing condition, the posterior plate group produced the lowest relative displacement (RD) among all the groups (0.01, 0.03 and 0.06mm). Further nodal analysis of the highest RD fracture group showed a higher mean displacement of 4.77mm and 4.23mm in AP and PA lag screws model (p=0.000). The amounts of stress subjected to these implants, 134.36MPa and 140.75MPa were also significantly lower (p=0.000). There was a negative correlation (p=0.021) between implant stress and the displacement which signifies a less stable fixation using AP and PA lag screws.

CONCLUSION

Progressively increasing fracture size demands more stable fixation construct because RD increases significantly. Posterior buttress plate produces superior stability and lowest RD in PMF models irrespective of the fragment size.

Comparison of the direct and indirect reduction techniques during the surgical management of posterior malleolar fractures

Background

The optimal method for the reduction and fixation of posterior malleolar fracture (PMF) remains inconclusive. Currently, both of the indirect and direct reduction techniques are widely used. We aimed to compare the reduction quality and clinical outcome of posterior malleolar fracture managed with the direct reduction technique through posterolateral approach or the indirect reduction technique using ligamentotaxis.

Methods

Patients with a PMF involving over 25% of the articular surface were recruited and assigned to the direct reduction (DR) group or the indirect reduction (IR) group. Following reduction and fixation of the fracture, the quality of fracture reduction was evaluated in post-operative CT images. Clinical and radiological follow-ups were performed at 6 weeks, 3 months, 6 months, 12 months, and then at 6 month-intervals postoperatively. Functional outcome (AOFAS score), ankle range of motion, and Visual Analog Scale (VAS) were evaluated at the last follow-up. Statistical differences were compared between the DR and IR groups considering the patient demographics, quality of fracture reduction, AOFAS score, and VAS.

Results

Totally 116 patients were included, wherein 64 cases were assigned to the DR group and 52 cases were assigned to the IR group. The quality of fracture reduction was significant higher in the DR group (P = 0.038). In the patients who completed a minimum of 12 months’ follow-up, a median AOFAS score of 87 was recorded in the DR group, which was significantly higher than that recorded in the IR group (a median score of 80). The ankle range of motion was slightly better in the DR group, with the mean dorsiflexion restriction recorded to be 5.2° and 6.1° in the DR and IR group respectively (P = 0.331). Similar VAS score was observed in the two groups (P = 0.419).

Conclusions

The direct reduction technique through a posterolateral approach provide better quality of fracture reduction and functional outcome in the management of PMF over 25% of articular surface, as compared with the indirect reduction technique using ligamentotaxis.

Trial registration

NCT02801474 (retrospectively registered, June 2016, ClinicalTrails.gov).

3-D computer modelling of malunited posterior malleolar fractures: effect of fragment size and offset on ankle stability, contact pressure and pattern

BACKGROUND

The positioning of the fracture fragment of a posterior malleolus fracture is critical to healing and a successful outcome as malunion of a posterior malleolar fracture, a condition seen in clinical practice, can affect the dynamics of the ankle joint, cause posterolateral rotational subluxation of the talus and ultimately lead to destruction of the joint. Current consensus is to employ anatomic reduction with internal fixation when the fragment size is larger than 25 to 33% of the tibial plafond.

METHODS

A 3-dimensional finite element (FE) model of ankle was developed in order to investigate the effect of fragment size (6-15 mm) and offset (1-4 mm) of a malunited posterior malleolus on tibiotalar joint contact area, pressure, motion of joint and ligament forces. Three positions of the joint were simulated; neutral position, 20° dorsiflexion and 30° plantarflexion.

RESULTS

Compared to the intact joint our model predicted that contact area was greater in all malunion scenarios considered. In general, the joint contact area was affected more by section length than section offset. In addition fibula contact area played a role in all the malunion cases.

CONCLUSIONS

We found no evidence to support the current consensus of fixing posterior malleolus fractures of greater than 25% of the tibial plafond. Our model predicted joint instability only with the highest level of fracture in a loaded limb at an extreme position of dorsiflexion. No increase of peak contact pressure as a result of malunion was predicted but contact pattern was modified. The results of our study support the view that in cases of posterior malleolar fracture, posttraumatic osteoarthritis occurs as a result of load on areas of cartilage not used to loading rather than an increase in contact pressure. Ankle repositioning resulted in increased force in two ankle ligaments. Our finding could explain commonly reported clinical observations.

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.

Longterm outcome of 886 posterior malleolar fractures: A systematic review of the literature

INTRODUCTION

The objective of the present study was to review the current data on the long-term outcomes of posterior malleolar fractures, with special emphasis on the role of the type of treatment, surgical approach, and reduction and internal fixation.

METHODS

The search was limited to skeletally mature patients. Major databases were searched from 1978 to 2014 to identify studies relating to functional outcome, subjective outcome, and radiographic evaluation at least 2 years after either surgical or conservative treatment of posterior malleolar fractures.

RESULTS

Of 68 initially relevant studies, 19 met our inclusion criteria. A total of 886 fractures were identified in 885 patients. The mean sample size-weighted follow-up period was 3.7 years. Comparable results are achieved when comparing open reduction and internal fixation to conservative treatment for posterior malleolar fractures.

DISCUSSION

Current consensus suggests posterior malleolar fragments comprising of >25% of the distal tibial plafond as seen on a true lateral radiograph and fragments with more than 2mm dislocation require open reduction and internal fixation of the fragment. The current consensus on treatment of posterior malleolar fractures is neither supported nor disapproved by the available evidence.

Impact of trimalleolar ankle fractures: how do patients fare post-operatively?

BACKGROUND

We aim to evaluate the clinical and functional outcome of trimalleolar fractures and the ability of patients to return to sporting activities.

METHODS

A retrospective review of 31 patients with operatively managed trimalleolar fractures was conducted. Their Olerud and Molander scores and ability to return to sports was analyzed at 1 year postoperatively.

RESULTS

Dislocations were more likely to result from trimalleolar fractures (p<0.001). 11 (52.4%) of our patients had residual pain at 1 year. 13 (61.9%) and 10 (47.6%) had persistent ankle stiffness and swelling. Out of 12 patients who were involved in sports pre-operatively, only 4 (33.3%) patients were able to return to sports. 3 (25%) patients were unable to do sports at all. Increasing posterior malleolar fragment size correlates with poorer functional outcome.

CONCLUSIONS

Patients have poorer functional outcome with increasing posterior malleolar fragment size in trimalleolar fractures. Residual deficits affect the majority of our patients and a notable proportion was unable to return to sporting activities.