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

Safety and exposure area in three different posteromedial surgical approaches for the treatment of ankle fractures. A cadaveric study

INTRODUCTION

This study aimed to compare the degree of posterior malleolar exposure, the tension of the flap containing the posteromedial neurovascular bundle (NVB), and the distance between the surgical incision and the NVB using three different posteromedial ankle approaches.

METHODS

Three approaches were compared: medial posteromedial (MePM) modified posteromedial (MoPM) and posteromedial (PM). We measured the minimal tension of the flap containing the NVB that allowed proper exposure. In the second stage, an axial cut was performed, and we measured the degree of posterior malleolar exposure and the distance between the incision and the NVB RESULTS: There were significant differences between the three approaches examined regarding the degree of posterior malleolar exposure and distance from the incision to the NBV,favoring the PM approach (71,00% ± 1.83 and 25.50 mm ± 4.20). The PM approach provided a significantly lower tension to the flap containing the posteromedial NVB (6.18 N ± 1.28) compared to the other two approaches CONCLUSION: The PM approach achieved the highest degree of posterior malleolar exposure, the lowest tension to the posteromedial NVB, and the greatest distance between the incision and the NBV. Thus, we believe it should be considered the approach of choicefor large fractures of the posteromedial aspect of the PM.

Tibialis posterior tendon entrapment in posterior malleolar and pilon injuries of the ankle: a retrospective analysis

BACKGROUND

The Tibialis Posterior tendon (TPT) is the only tendon to encounter the distal tibia and is therefore at greatest risk of injury in fractures of the distal tibia. Although TPT injury has been reported rarely with injuries around the ankle, they often have been missed and present late.

AIM

Our aim was to analyse the rate to TPT entrapment in fractures involving the posterior tibia, i.e. Pilon (PLM) and posterior malleolar fractures (PMF).

METHODS

A retrospective analysis of PMF and Pilon fractures over an 8-year period was undertaken. Patients who had undergone surgical fixation of their PMF or PLM were identified from 2014 to 2022, using our prospectively collected database. Any fracture which had undergone a preoperative CT was included. Analysis of their pre-operative CT imaging was utilised to identify TPT entrapment, where if < 50% of the tendon cross section was present in the fracture site, this was denoted as a minor entrapment and if ≥ 50% of the tendon was present in the fracture site was denoted as major.

RESULTS

A total of 363 patients were identified for further analysis, 220 who had a PMF and 143 with PLM injury. The incidence of TPT entrapment was 22% (n = 79) with 64 minor and 15 major entrapments. If the fracture line entered the TPT sheath, there was a 45% rate (72/172) of entrapment as compared to 3.7% (7/190) in fractures not entering the sheath (p < .001). There was no significant difference in TPT entrapment in PMF as compared to PML (p = 0.353).

CONCLUSION

In our assessment, we found significant prevalence of 22% of TPT entrapment in fractures involving the posterior tibia. PMF and PLF had no statistically significant difference in the rate of TPT entrapment. Additionally, we found that there was a significant risk of TPT entrapment when the CT images display the fracture line entering the tendon sheath. We recommend that surgeons consider taking care assessing pre-operative imaging to seek to identify the TPT and to assess intraoperatively where entrapment does occur.

Current concepts in ankle fractures

Ankle fractures are among the most common orthopaedic injuries. Operative management is performed in unstable ankle fracture patterns to restore the stability and native kinematics of the ankle mortise and minimize the risk of post-traumatic degenerative changes. In this study, we review current concepts in ankle fracture management, including posterior malleolus fixation, syndesmosis fixation, deltoid ligament repair, fibular nailing, and early weightbearing, from both a biomechanical and clinical perspective.

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.

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.

Ultrasound evaluation of a new surface reference line to describe sural nerve location and safe zones to consider in posterior leg approaches

PURPOSE

Several authors have described methods to predict the sural nerve pathway with non-proportional numerical distances, but none have proposed a person-proportional, reproducible method with anatomical references. The aim of this research is to describe ultrasonographically the distance and crossing zone between a surface reference line and the position of the sural nerve.

METHODS

Descriptive cross-sectional study, performed between January and April 2022 in patients requiring foot surgery who met inclusion criteria. The sural nerve course in the posterior leg was located and marked using ultrasound. Landmarks were drawn with a straight line from the medial femoral condyle to the tip of the fibula. Four equal zones were established in the leg by subdividing the distal half of the line. This way, areas based on simple anatomical proportions for each patient were studied. The distance between the marking and the ultrasound nerve position was measured in these 4 zones, creating intersection points and safety areas. Location and distances from the sural nerve to the proposed landmarks were assessed.

RESULTS

One-hundred and four lower limbs, 52 left and 52 right, assessed in 52 patients were included. The shortest median distance of the nerve passage was 2.9 mm from Point 2. The sural nerve intersection was 60/104 (57.7%) in Zone B, 21/104 (20.1%) in Zone C and 19/104 (18.3%) in Zone A. Safety zones were established. Average 80.5% of coincidence in sural nerve localization was found in the distal half of the leg, in relation to the surface reference line when comparing both legs of each patient.

CONCLUSIONS

This study proposes a simple, reproducible, non-invasive and, for the first time, person-proportional method, that describes the distance and location of the main areas of intersection of the sural nerve with points and zones (risk and safe zones) determined by a line guided by superficial anatomical landmarks. Its application when surgeons plan and perform posterior leg approaches will help to avoid iatrogenic nerve injuries.

LEVEL OF EVIDENCE

IV.

Fracture gap of the lateral malleolus via posterolateral approach: Improved visualization of the posterior malleolus fracture

The treatment of posterior malleolar fractures is a popular issue. Anatomic reduction of posterior malleolar fractures is critical for re-establishing the stability of the ankle mortise and ligamentous union after trauma. Inappropriate treatment ultimately leads to poorer functional outcomes and lower quality of life. Open reduction and internal fixation through a posterolateral approach are preferred over indirect reduction and anterior-posterior screw fixation. Although the posterolateral approach, which is more common and direct, provides good exposure to the fracture site, it has some limitations. In this report, we describe the posterolateral approach through the lateral ankle fracture gap for the treatment of posterior ankle fractures. Moreover, we discuss the indications, benefits, and limitations of this approach.

Unstable Rotational Ankle Fractures Treated With Anatomic Mortise Repair and Direct Posterior Malleolus Fixation

Introduction: The purpose of this study was to evaluate patient outcomes following a standardized algorithmic approach to ankle mortise stabilization, following rotational fracture, utilizing direct repair of the posterior malleolus in the prone position. Methods: Eighty consecutive patients with unstable rotational ankle fractures that involved the posterior malleolus were analyzed. All underwent direct repair of the posterior malleolus regardless of size through a posterolateral approach. Electronic records were retrospectively reviewed for demographic information, initial injury and operation details, healing status, and complications. Preoperative and postoperative radiographs were obtained to assess the initial injury and healing was determined both by radiographic and clinical progress at follow-up visits. Results: Average posterior malleolus fragment width was 8.1 ± 3.7 mm (range = 2.1-19.9 mm) and percentage of the articular surface was 23.6% (range = 7.1%-56.7%) on the lateral radiograph. Overall, 80/80 (100%) patients healed their ankle fractures by a mean 2.9 ± 1.1 months. Only 1 (1.3%) patient required transsyndesmotic fixation following posterior malleolus repair. Mean range of ankle motion was as follows: dorsiflexion 20° ± 10°, plantarflexion 34° ± 10°, inversion 8° ± 4°, and eversion 7° ± 4°. Seventy-nine patients (98.8%) had an anatomic mortise reduction. Nine patients (11.3%) had a superficial wound complication, 3 patients (3.8%) had dysesthesia in the sural nerve distribution, and 1 patient (1.3%) lost reduction of the medial malleolus. Conclusion: Patients who undergo direct repair of the posterior malleolus in the prone position can expect a high rate of healing with superficial wound breakdown being the biggest problem, which was associated with an ankle fracture dislocation. Posterior malleolus fixation may obviate the need of transsyndesmotic stabilization.Levels of Evidence: Retrospective Level IV.