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

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.

Analysis of the epidemiological characteristics of posterior malleolus fracture in adults

BACKGROUND

This study explores the latest epidemiological characteristics of posterior malleolus fracture and compares the epidemiological differences of posterior malleolus fracture in different periods, regions, and adult age groups.

METHODS

Clinical information of inpatients with posterior malleolus fracture in Shanghai Tongji Hospital and Karamay Central Hospital from January 2014 to February 2022 was reviewed and collected. The imaging data of patients were acquired using the Picture Archiving and Communication Systems. A statistical analysis was performed as to gender, current age, year of admission, injury mechanism, fracture type, and posterior malleolus fracture classification. Moreover, a comparative analysis was conducted on the injury mechanisms and morphological differences of posterior malleolus fracture at different periods, regions, and age groups.

RESULTS

A total of 472 patients (210 patients from Shanghai Tongji Hospital and 262 patients from Karamay Central Hospital) with posterior malleolus fracture and an average age of 48.7 ± 15.6 were included in this study. The peak of posterior malleolus fracture occurs in the age group of 50-59. The injury mechanisms mainly involve low-energy fall and sprain (411 cases, 87.1%), followed by traffic accidents (52 cases, 11.0%), and fall injury from height (9 cases, 1.9%). With aging, the number of fall and sprain cases increases and reaches the peak at the age of 50-59, followed by progressive decline. Traffic accidents presents a relatively flat small peak in the age group of 40-59. The number of cases according to different fracture types shows the following ascending order: trimalleolar fracture-supination external rotation (335 cases, 71.0%) > bimalleolar fracture (60 cases, 12.7%) > trimalleolar fracture-pronation extorsion (43 cases, 9.1%) > posterior malleolus + tibial shaft fracture (19 cases, 4.0%) > simple posterior malleolus fracture (15 cases, 3.2%). The numbers of cases corresponding to the Haraguchi I Type, II Type, and III Type of posterior malleolus fractures were 369 (78.2%), 49 (10.4%), and 54 (11.4%), respectively. The Tongji IIA Type represented the highest number of cases (249 cases, 52.8%), followed by the IIB Type (120 cases, 25.4%), I Type (54 cases, 11.4%), IIIB Type (36 cases, 7.6%), and IIIA type (13 cases, 2.8%). The trimalleolar fracture-supination external rotation, Haraguchi I Type and Tongji IIA Type of posterior malleolus fractures all presented an obvious peak of incidence in the age group of 50-59. However, no obvious statistical difference was observed in the injury mechanism, Haraguchi classification, and Tongji classification of posterior malleolus fractures among different years and regions in recent years (P > 0.05).

CONCLUSIONS

The injury mechanism of posterior malleolus fracture mainly involves low-energy fall and sprain cases. The trimalleolar fracture-supination external rotation, Haraguchi I type and Tongji IIA type of posterior malleolus fracture are predilection fracture types, and all present an obvious incidence peak in the age group of 50-59. Elderly patients have high risks of falling and their bones are more fragile, conditions which are potential risk factors of posterior malleolus fracture. Early positive control has important significance. This study provides references for relevant basic and clinical studies of posterior malleolus fracture.

Arc center distance as a novel quantitative radiographic parameter for volar Barton fractures

PURPOSE

The aims of this study were to investigate conventional radiographic parameters and introduce a novel parameter (arc center distance, ACD) for volar Barton fractures.

METHODS

Twenty-four cases of volar Barton fracture were retrospectively analyzed. We measured volar tilt angle (VTA), anteroposterior distance (APD), teardrop angle (TDA), and capitate-to-axis-of-radius distance (CARD) on lateral plain radiographs. The ACD was measured on the sagittal images of computed tomography scans. VTAs, APDs, TDAs, and CARDs were compared between the fractured and normal contralateral wrist. The area under the receiver operating characteristic curve was calculated for each parameter.

RESULTS

TDAs did not differ significantly between the fractured wrists and the controls. On the other hand, VTAs, APDs, and CARDs were all significantly greater in the fractured wrists (mean values were 17.25°, 20.70 mm, and - 3.40 mm, respectively). The area under the curve value was highest (0.943) for the ACD. When a cutoff value of 1.02 mm was used as a threshold, a sensitivity of 100% and specificity of 80.95% were achieved.

CONCLUSIONS

The mean values of conventional parameters (VTA, APD, TDA and CARD) in volar Barton fractures were presented. The ACD can be useful parameter for quantitatively evaluating volar Barton fractures.

Reduction of olecranon fractures with no or minimal dorsal cortex comminution based on the contour of the posterior ulnar cortex: does it restore the greater sigmoid notch?

INTRODUCTION

When treating olecranon fractures surgically, surgeons rely on the contour of the posterior cortex of the proximal ulna. However, it is unclear whether the greater sigmoid notch (GSN) is restored anatomically by this method. We analyzed whether reduction of fractures based on the posterior ulnar cortex contour is reliable for restoration of the GSN contour in displaced olecranon fractures with no or minimal dorsal cortex comminution.

MATERIALS AND METHODS

We performed a retrospective review of 23 patients with Mayo type 2 olecranon fractures with no or minimal dorsal cortex comminution who were treated surgically. We analyzed pre- and postoperative elbow CT images and measured the interfragmentary distance (IFD), articular step-off, articular gap, contour defect and GSN angle to evaluate the restoration of the GSN contour.

RESULTS

The mean preoperative IFD and contour defect were 16.5 mm (range 4.3-35.6 mm) and 4.3 mm (range 0.7-13.3 mm), respectively. Postoperatively, there was no residual IFD, and the mean contour defect decreased significantly to 1.4 mm (range 0-3.7 mm). The residual articular step-off and gap were 0.2 mm (range 0-3.8 mm) and 1.0 mm (range 0-5.9 mm), respectively. Acceptable GSN restoration was achieved in 14 of 23 patients (60.9%). Sixteen patients had > 2 mm of preoperative contour defect, and 7 (43.8%) achieved acceptable GSN restoration; the remaining 7 patients (100%) who had < 2 mm of the contour defect achieved acceptable GSN restoration. Patients whose preoperative contour defect was > 2 mm had a higher risk of unacceptable GSN restoration, with an odds ratio of 2.29 (p = 0.019).

CONCLUSIONS

In displaced olecranon fractures without significant dorsal cortex comminution, reduction based on the posterior ulnar cortex could be reliable for fractures with under 2 mm of preoperative contour defect, but not for those with > 2 mm of contour defect.

LEVEL OF EVIDENCE

IV.

Arc Centre Distance Change after Treatment of Complex Transverse Olecranon Fractures with a Large Impacted Articular Fragment Treated with Tension Band Wiring and Bone Graft

Background: The treatment of complex transverse olecranon fractures (CTOFs), also known as olecranon fractures with the impacted articular fragments (IAF), was reported recently. We fix IAFs with absorbable pins supported by autologous bone graft followed by olecranon fracture fixation. We have used the arc centre distance (ACD) method to evaluate the congruency of this concentric hinge joint. The aim of this study is to present the outcomes of this fixation technique and evaluate the value of the ACD method.

Methods: We reviewed 26 cases of CTOF treated at our hospital from 2014 to 2020. The functional outcome and range of motion of the elbow joint was measured by MEPS (Mayo Elbow Performance Score). We measured the ACD of each fragment of the ulnotrochlear joint [coronoid process (CP), IAF and olecranon process (OP)] with the CT image taken at 15 months postoperatively on average.

Results: The mean arc of elbow motion was 3º to 132º. The mean MEPS at 1 year postoperatively was 94, and 25 of 26 cases (96%) achieved a good or excellent outcome. Twelve patients, who took the elbow CT at least more than 3 months post-operatively, were included for ACD measurement. The postoperative joint incongruency of each fragment was as follows, 0.39 ± 0.70, 0.40 ± 0.69 and 0.29 ± 0.72 mm (CP, IAF and OP, respectively) according to the ACD method. The ACD value for each fragment was significantly different before and after the surgery (p < 0.05).

Conclusions: Accurate reduction of IAF with absorbable pins completed by tension band wiring with autogenous bone grafting can be an effective technique for CTOF with a large IAF. The restoration of the joint improved ACD.

Level of Evidence: Level IV (Therapeutic)

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.