Patient reported outcomes following non-operatively managed Weber Type A distal fibula fractures

Patients with more complex ankle fractures are associated with poorer patient-reported outcome: an observational study of 11,733 patients from the Swedish Fracture Register

BACKGROUND AND PURPOSE

Patient-reported outcome measures (PROMs) following ankle fractures, including all fracture types, have not been reported. It is therefore unclear whether fracture morphology correlates with outcome. We aimed to analyze PROMs in patients with an ankle fracture in relation to the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) fracture classification using population-based register data from the Swedish Fracture Register (SFR).

METHODS

All patients aged ≥ 18 years with an ankle fracture (AO/OTA 44A1-C3) registered in the SFR between 2012 and 2019 were retrieved from the register. Patients with completed PROM questionnaires (Short Musculoskeletal Function Assessment and EuroQol-Visual Analogue Scale) on both day 0 (pre-trauma) and 1-year post-trauma were included. The difference in PROMs between day 0 and 1 year was calculated for each patient (delta value) and mean delta values were calculated at group level, based on the AO/OTA fracture classification.

RESULTS

11,733 patients with 11,751 fractures with complete PROMs were included. According to the AO/OTA classification, 21% were A fractures, 67% were B fractures and 12% were C fractures. All groups of patients, regardless of fracture class (A1-C3), displayed an impairment in PROMs after 1 year compared with day 0. Type C fractures displayed a larger impairment in PROMs at group level than type B, which in turn had a greater impairment than type A. The same pattern was seen in groups 3, 2, and 1 for A and B fractures.

CONCLUSION

We found that the AO/OTA classification is prognostic, where more complex fractures were associated with poorer PROMs.

Finite element analysis and a pilot study of different fixation constructs for Danis-Weber A and B lateral malleolus fractures

BACKGROUND

Displaced lateral malleolus fractures are typically stabilised through open reduction and internal fixation. The biomechanically and clinically efficacy of locking plates and lag screws, particularly in Weber A and B distal fibular fractures remains a subject of contention. This study examines two locking plate designs for lateral malleolus fractures, evaluating their performance with and without interfragmentary screws using finite element models.

METHODS

Utilising CT images of a healthy adult male volunteer, a three-dimensional finite element model was constructed. The Fibula-specific Flank Multiaxial Locking Anatomic Plate (FMLP) and the Conventional Locking Plate (CLP) were subjected to stabilisation, both with and without an interfragmentary screw, mimicking the Danis-Weber A and B lateral malleolus oblique fracture fixation. Loads of 140 N and 70 N, equivalent to 20% of the body weight, were applied to simulate the single-leg and two-leg standing conditions in the axial direction. The von Mises stress (VMS) distributions and element displacements were subsequently analyzed.

RESULTS

In the Danis-Weber A fracture model group, the FMLP with an interfragmentary screw fixation exhibited the lowest peak VMS values: 51.9 MPa in the fibula, 89.0 MPa in the plate, and 61.3 MPa in the screws for simulating single-leg conditions. Under two-leg standing conditions, these peak VMS values decreased to 25.9 MPa in the fibula, 44.5 MPa in the plate, and 30.6 MPa in the screws, respectively. Furthermore, the overall structural peak displacements during single-leg standing for both Weber-A and B fractures with different implants ranged from 1.61 to 2.54 mm. While standing on two feet, the ranged was from 0.80 to 1.27 mm. An interfragmentary screw at the oblique fracture site resulted in reduced the peak value of VMS in the fibula, plate, screws, consequently decreased the overall structural displacement for FMLP and CLP fixation in lateral malleolus fractures.

CONCLUSIONS

The current finite element analysis (FEA) demonstrates that FMLP exhibits superior mechanical characteristics in Danis-Weber A and B lateral malleolus fractures compared to CLP. The inclusion of an interfragmentary screw, combined with locking plate design, enhances stability for simple oblique distal fibular fractures. The FMLP presents itself as potential as an alternative for lateral malleolus fractures from a biomechanical perspective. Nevertheless, further verification of these results is imperative through subsequent clinical studies.