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

A bending model for assessing relative stiffness and strength of orthopaedic fixation constructs

BACKGROUND

The purpose of this study is to develop a simple and reproducible bending model that is compatible with a wide range of orthopaedic fixation devices and 3D printed spacers.

METHODS

A robust 4-point bending model was constructed by securing sawbones blocks with different orthopaedic fixation device constructs. Stress strain curves derived from a fundamental mechanics model were used to assess the effect of bone density, type of hardware (staple vs intramedullary beam), the use of dynamic compression, orientation of staples (dorsal vs plantar), and the use of 3D printed titanium spacers.

FINDINGS

The high throughput 4-point bending model is simple enough that the methods can be easily repeated to assess a wide range of fixation methods, while complex enough to provide clinically relevant information.

INTERPRETATIONS

It is recommended that this model is used to assess a large initial set of fixation methods in direct and straightforward comparisons.

Classifications of posterior malleolar fractures: a systematic literature review

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Background

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

Methods

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

Results

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

Conclusion

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

Level of evidence

Level III, therapeutic.

Difference in Joint Stability Between Small Posterior Malleolar Fragments With Fixation and Those Without Fixation: A Biomechanical Cadaver Study

The indication for the surgical treatment of ankle fractures that involve a posterior malleolar fragment remains controversial. This cadaver study assessed the biomechanical results of rotation stiffness of Haraguchi type 1 posterior malleolar fragments with or without cannulated screw fixation. Twelve anatomic lower-extremity specimens from 6 cadavers were tested. Six right legs were subjected to posterior malleolus osteotomy (Haraguchi type I) followed with (group A; n = 3) or without (group B; n = 3) fixation using a cannulated screw. Ankle joint stability was measured under both external rotation force and axial loading, and the passive resistive torque was measured in both groups. The mean torque value in group A was 0.1093 Nm/º, while that in group B was 0.0537 Nm/º. There was a significant intergroup difference (p = .004). In group B, the torque value was further increased in the latter rotation period (about 40-60 degrees). Group A proved more stable under experimental conditions than group B. Fixation in type I posterior malleolar fragments produced improved stability in ankle rotation, even for posterior malleolar fragments involving <25% of the articular surface, and has been considered an effective aid in treatment.

The Statistical Fragility of Foot and Ankle Surgery Randomized Controlled Trials

Fragility index (FI) is a metric used to interpret the results of randomized controlled trials (RCTs), and describes the number of subjects that would need to be switched from event to non-event for a result to no longer be significant. Studies that analyze FI of RCTs in various orthopedic subspecialties have shown the RCTs to be largely underpowered and highly fragile. However, FI has not been assessed in foot and ankle RCTs. The MEDLINE and Embase online databases were searched from 1/1/2011 through 11/19/2021 for RCTs involving foot and ankle conditions. FI, fragility quotient (FQ), and difference between the FI and number of subjects lost to follow-up was calculated. Spearman correlation was performed to determine the relationship between sample size and FI. Overall, 1262 studies were identified of which 18 were included in the final analysis. The median sample size was 65 (interquartile range [IQR] 57-95.5), the median FI was 2 (IQR 1-2.5), and the median FQ was 0.026 (IQR 0.012-0.033). Ten of 15 (67%) studies with non-zero FI values had FI values less than the number of subjects lost to follow-up. There was linear association between FI and sample size (R² = 0.495, p-value: .031). This study demonstrates that RCTs in the field of foot and ankle surgery are highly fragile, similar to other orthopedic subspecialties.

[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.

Use of an aiming drill guide and ankle arthroscopy for reduction of depressed articular surface in posterior malleolar fractures

PURPOSE

We describe a novel technique that uses an aiming drill guide and ankle arthroscopy for direct visualization and reduction of the depressed articular surface located between the posterior tibia and the fractured posterior malleolus. This technique requires less soft tissue dissection to visualize and reduce the depressed articular surface.

METHODS

Between June 2014 and May 2019, 126 patients were surgically treated for trimalleolar fractures. Among them, 11 had depressed articular fragment between the posterior tibia and the fractured posterior malleolus reduced using our novel technique. The study included six men and five women, with a mean age of 46.5 (range: 23-62) years.

RESULTS

In eight (73%) cases, the articular surface was reduced, with the articular surface step-off being less than 2 mm, as noted on postoperative computed tomography (CT). Syndesmosis congruity within an anterior-to-posterior difference of less than 2 mm was confirmed in nine (82%) cases via postoperative CT. The mean 100-mm visual analog scale (VAS) and the mean Olerud-Molander ankle score at the final follow-up were 16.6 ± 14.5 and 87.7 ± 7.5, respectively.

CONCLUSIONS

The depressed articular fragment located between the posterior tibia and the fractured posterior malleolus can be treated using an aiming drill guide and ankle arthroscopy. Ankle arthroscopy is used for direct visualization of the depressed articular surface, and the aiming drill guide can guide the bone plunger precisely to the depressed articular surface for reduction. This technique requires less soft tissue dissection than conventional techniques to visualize and reduce the depressed articular surface.