Clinical outcomes and trans-syndesmotic screw frequency after posterior malleolar fracture osteosynthesis

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Quantitative Evaluation of the Influence of Posterior Malleolus Fracture and Fixation on the Rotational Stability of the Ankle

Background

This study aimed to analyze quantitative correlation between the posterior malleolus fracture and fixation and the rotational stability of the ankle and to explore supplementary surgical indications for posterior malleolus fracture.

Methods

Twenty fresh frozen cadaver specimens were selected and dissected. Based on the tibial insertion of the ligament complex, the model for the supination external rotation stage 3 ankle fracture with a posterior malleolar fragment and syndesmosis diastasis was created. The area threshold of the posterior tibial insertion of posterior malleolus fracture was biomechanically assessed and the difference of the antirotating ability stiffness of the ankle between simple posterior malleolus fixation and simple syndesmotic fixation was analyzed statistically.

Results

The tibial insertion of posterior inferior tibiofibular ligament and inferior transverse tibiofibular ligament complex was relatively broad, and its width decreased as the distance from the joint line increased. Biomechanical analysis showed that: the threshold of posterior area of posterior malleolus fracture was 1/4S; posterior malleolus fixation provided better rotational stability than syndesmotic fixation (P < 0.01).

Conclusion

The surgical indications for posterior malleolus fracture should consider simultaneously the restoration of the axial and rotational stability of the ankle. Simple posterior malleolus fracture fixation is recommended when the syndesmosis is unstable and the area ratio of posterior tibial insertion of posterior malleolus fracture is greater than or equal to 1/4. Syndesmotic fixation is proposed to restore and maintain the rotational stability of the ankle when the syndesmosis is unstable and the area ratio is less than 1/4. Regardless of the area ratio, the surgical indication only depends on the impact of the posterior malleolus fracture on the axial stability of tibiotalar joint, the involved articular surface area, and the displacement degree of posterior malleolus fragment, when the syndesmosis is stable.

Open Reduction and Internal Fixation of the Posterior Malleolus Fragment in Ankle Fractures Improves the Patient-Rated Outcome: A Systematic Review

BACKGROUND

The best treatment strategy for fractures to the posterior malleolus (PM) is still intensively debated. The aim of this systematic review was to compare the patient-rated outcome following open reduction and internal fixation (ORIF) for fractures of the PM to either closed reduction using AP screws (CRIF) or no treatment in bi- or trimalleolar ankle fractures.

METHODS

Systematic literature research (MEDLINE (PubMed), CINAHL, Scopus, Central and EMBASE) according to the PICOS and PRISMA guidelines. Eligible were studies comparing the outcome following ORIF to any other treatment strategy for fractures to the posterior malleolus in isolated bi- or trimalleolar ankle fractures.

RESULTS

Twelve studies were eligible for a qualitative analysis and 6 for a quantitative analysis. Overall, a considerable heterogeneity among the studies was observed. The most commonly used outcome score was the American Orthopaedic Foot & Ankle Society ankle-hindfoot score (AOFAS). The final follow-up ranged from 12 to 160 months. Four studies compared ORIF to CRIF of the PM. The quantitative analysis revealed significantly better AOFAS scores for ORIF (90.9 vs 83.4 points; P < .001; I2 = 0%). Three studies compared ORIF to untreated PM fragment. The quantitative analysis again revealed superior AOFAS scores for ORIF (92.0 vs 82.5 points; P < .001; I2 = 99%). A similar trend was observed for the Ankle Fracture Scoring System and American Academy of Orthopaedic Surgeons Foot and Ankle Questionnaire scores as well as the quality of reduction.

CONCLUSION

Despite a considerable heterogeneity, the data available point to a superior outcome following ORIF for fractures to the PM when compared to CRIF or no treatment.

Instability of the distal tibiofibular syndesmosis

The distal tibiofibular syndesmosis (DTFS) is more frequently injured than previously thought. Early diagnosis and appropriate treatment is essential to avoid long term complications like chronic instability, early osteoarthritis and residual pain. Management of these injuries require a complete understanding of the anatomy of DTFS, and the role played by the ligaments stabilizing the DTFS and ankle. High index of suspicion, appreciating the areas of focal tenderness and utilizing the provocative maneuvers help in early diagnosis. In pure ligamentous injuries radiographs with stress of weight bearing help to detect subtle instability. If these images are inconclusive, then further imaging with MRI, CT scan, stress examination under anesthesia, and arthroscopic examination facilitate diagnosis. An injury to syndesmosis frequently accompanies rotational fractures and all ankle fractures need to be stressed intra-operatively under fluoroscopy after fixation of the osseous components to detect syndesmotic instability. Non-operative treatment is appropriate for stable injuries. Unstable injuries should be treated operatively. Anatomic reduction of the syndesmosis is critical, and currently both trans-syndesmotic screws and suture button fixation are commonly used for syndesmotic stabilization. Chronic syndesmotic instability (CSI) requires debridement of syndesmosis, restoration of ankle mortise with or without syndesmotic stabilization. Arthrodesis of ankle is used a last resort in the presence of significant ankle arthritis. This article reviews anatomy and biomechanics of the syndesmosis, the mechanism of pure ligamentous injury and injury associated with ankle fractures, clinical, radiological and arthroscopic diagnosis and surgical treatment.

Posterior to anterior malleolar extended lateral approach to the ankle (PAMELA): early results of a novel approach

INTRODUCTION

In a previous cadaveric study, we described the Posterior to Anterior Malleolar Extended Lateral Approach (PAMELA) to address complex ankle fractures. It was demonstrated to provide optimal exposure of the posterior and lateral malleoli, and of the anterolateral portion of the ankle through a single incision. The aim of this study is to report the clinical results of this novel approach.

METHODS

Between January 2019 and January 2021, all patients presenting with a complex ankle fracture in our institution were assessed by CT scan. Indication to use the PAMELA was determined by the fracture pattern, according to our previous guidelines, including combination of complex lateral and displaced posterior malleolar fractures, associated in most cases with anterolateral fracture avulsion. The approach was performed according to the steps previously described. Intraoperative evaluation included quality of exposure, ease of performing the osteosynthesis, and any complication encountered. The postoperative course was assessed for wound healing, quality of reduction, and the occurrence of any complication.

RESULTS

The PAMELA was performed in 20 patients (aged 17-73). The most common combination of fractures was a comminuted lateral malleolus fracture associated with a displaced fracture of the posterior malleolus and a Wagstaffe-Le Fort or Chaput avulsion. We encountered no intraoperative complication. X-rays showed anatomical reduction in all cases. Postoperative complications included three delayed wound healing resolved with local treatment and one sural nerve traction injury.

CONCLUSIONS

The main potential concern regarding this novel approach was the healing of the flap. Our results reject this concern and are in line with wound healing complications reported following surgical treatment of ankle fractures. This study confirms the safe in vivo feasibility of the PAMELA and opens a new perspective in the optimal management of complex fractures of the ankle. A larger prospective clinical study is ongoing in our institution.

OUTCOMES AFTER UNSTABLE FRACTURES OF THE ANKLE: WHAT'S NEW? A SYSTEMATIC REVIEW

BACKGROUND

Unstable ankle fractures are very frequent. Given the instability, they often require surgical treatment, but literature scarcely reports on the outcomes of their management.

QUESTIONS/PURPOSES

For this systematic review we asked: (1) What are the outcomes in treatment of unstable ankle fractures? (2) What about complications of treatment in unstable fractures? (3) What factors influence the outcomes? (4) What about the role of the posterior malleolus?

METHODS

The electronic databases PubMed, Scopus, and Embase were interrogated using the search terms "bimalleolar" or "trimalleolar" and "fracture". Studies were included if they reported on: (1) bimalleolar or trimalleolar fracture in adults; (2) treatment; (3) outcomes reported by scales; (4) follow-up. The final review included 33 studies. The quality of the studies was evaluated with the Methodological Index for Non-randomized Studies (MINORS) questionnaire.

RESULTS

All the outcomes of the thirty-three selected studies were analyzed.

DISCUSSION

Surgical fixation of unstable ankle fractures should always be performed within the first 48 hours from the trauma, preventing instability and post-traumatic osteoarthritis. Surgeon should consider factor may influence functional outcomes. Posterior malleolar fractures should be fixed regardless the size, considering some individual factors.

Current management of trimalleolar ankle fractures

A trimalleolar ankle fracture is considered unstable and treatment is generally performed operatively. Computed tomography is important for the operative planning by providing an elaborated view of the posterior malleolus.

Trimalleolar ankle fractures have a rising incidence in the last decade with up to 40 per 100,000 people per year. With a growing number of elderly patients, trimalleolar ankle injuries will become more relevant in the form of fragility fractures, posing a particular challenge for trauma surgeons.

In patients with osteoporotic trimalleolar ankle fractures and relevant concomitant conditions, further evidence is awaited to specify indications for open reduction and internal fixation or primary transfixation of the ankle joint.

In younger, more demanding patients, arthroscopic-assisted surgery might improve the outcome, but future research is required to identify patients who will benefit from assisted surgical care.

This review considers current scientific findings regarding all three malleoli to understand the complexity of trimalleolar ankle injuries and provide the reader with an overview of treatment strategies and research, as well as future perspectives.

Cite this article: EFORT Open Rev 2021;6:692-703. DOI: 10.1302/2058-5241.6.200138

[Ankle fractures in older patients : What should we do differently?]

As a result of the demographic developments ankle fractures in older patients are part of routine trauma surgery. Due to comorbidities, such as diabetes mellitus, reduced bone quality and limited compliance in follow-up treatment, these fractures are prone to complications. The primary goal in the treatment of older patients with ankle fractures is to maintain mobility. In contrast to young patients most fractures are unstable pronation-abduction injuries. In the diagnostics the recognition and optimization of factors influencing the outcome, such as the blood perfusion and the generous use of computed tomography (CT) are recommended. As in the case of younger patients, conservative treatment is reserved for stable fracture forms and, if there are contraindications, should also be initiated in the case of unstable injuries. The choice of approaches is different for surgical treatment, which is adapted to the soft tissues, if necessary minimally invasive and increasingly carried out by a posterolateral approach. The initial transfixation can reduce soft tissue problems. Special surgical techniques and implants that provide a high level of stability, such as dorsal plate positioning, hook plates, angular stable plate systems and intramedullary systems as well as additional options, such as tibia pro fibula constructs are used. Primary retrograde nail arthrodesis is reserved as a salvage procedure only for exceptional cases. As part of the follow-up treatment, an interdisciplinary approach with respect for and optimization of concomitant diseases seems to make sense.