Could percutaneous fixation with crossed Schanz pins be an alternative to open reduction in the treatment of intra-articular calcaneal fractures?

Finite element analysis of modified Slongo's external fixation in the treatment of supracondylar humeral fractures in older children

Older children over 8 years old are at higher risk of elbow joint stiffness after treatment of supracondylar humeral fractures. The objective of this study was to improve the Slongo's external fixation system for treating supracondylar humeral fractures in older children. This would be achieved by increasing fixation strength and providing a theoretical basis through finite element analysis and mechanical testing. A 13-year-old female patient with a history of previous fracture was selected for CT data processing to create a three-dimensional model of the distal humerus fracture. Two internal fixation models were established, using the Slongo's external fixation method with Kirschner wire (Group A) and modifying the Slongo's external fixation (Kirschner wire tail fixation) (Group B). The fracture models were then subjected to mechanical loading analysis using Finite Element Analysis Abaqus 6.14 software to simulate separation, internal rotation, and torsion loads. A PVC humeral bone model was used to create a supracondylar fracture model, and the A and B internal fixation methods were applied separately. The anterior-posterior and torsional stresses were measured using the Bose Electroforce3510 testing system, followed by a comparative analysis. The finite element simulation results showed that under the same tensile, torsion, and inversion forces, the osteotomy model fixed with Kirschner wire at the distal end in Group B exhibited smaller tensile stress and deformation compared to the unfixed osteotomy model in Group A. This indicated that the fixation strength of Group B was superior to that of Group A. According to the test results of the Bose Electroforce3510 testing system, a simple linear regression analysis was conducted using SPSS software. The K values of rotation angle-torque tests and front and rear displacement-stress tests were calculated for Groups A and B, with Group B showing higher values than Group A. The results of this study supported the significantly enhanced biomechanical reliability and stability of fracture fixation in Group B, which utilized the modified Slongo's external fixation (Kirschner wire tail fixation). This optimized method provides a new choice for the clinical treatment of supracondylar humeral fractures in older children, backed by both clinical evidence and theoretical basis.

Biomechanical characteristics of Sanders type II and III calcaneal fractures fixed by open reduction and internal fixation and percutaneous minimally invasive fixation

BACKGROUND

This work investigated the differences in the biomechanical properties of open reduction and internal fixation (ORIF) and percutaneous minimally invasive fixation (PMIF) for the fixation of calcaneal fractures (Sanders type II and III calcaneal fractures as examples) through finite element analysis.

METHODS

Based on CT images of the human foot and ankle, according to the principle of three-point fixation, namely the sustentaculum tali, the anterior process and the calcaneal tuberosity were fixed. Three-dimensional finite element models of Sanders type II and III calcaneal fractures fixed by ORIF and PMIF were established. The proximal surfaces of the tibia, fibula and soft tissue were constrained, and ground reaction force and Achilles tendon force loads were added to simulate balanced standing.

RESULTS

The maximum stress was 80.54, 211.59 and 113.88 MPa for the calcaneus, screws and plates in the ORIF group and 70.02 and 209.46 MPa for the calcaneus and screws in the PMIF group, respectively; the maximum displacement was 0.26, 0.21 and 0.12 mm for the calcaneus, screws and plates in the ORIF group and 0.20 and 0.14 mm for the calcaneus and screws in the PMIF group, respectively. The values obtained from the simulation were within the permissible stress and elastic deformation range of the materials used in the model, and there was no significant stress concentration. The maximum stress and displacement of the calcaneus and implants were slightly lower in the PMIF group than in the ORIF group when fixing Sanders type II and III calcaneal fractures.

CONCLUSIONS

This study may provide a reference for optimising the design of implants, the development of individualised preoperative plans and the choice of clinical surgical approach.

Comparison of the Outcomes of Plating, Screw Fixation, and Pinning in Sanders Type II Fractures: A Multicenter (TRON) Retrospective Study

Calcaneus fractures Sanders type II have been historically treated with various modalities. However, few studies compared these procedures directly. The multicenter (TRON group) retrospective study compared the radiographic and clinical outcomes of operative procedures using Kirschner wires (K-wires), cannulated cancellous screws (CCSs) and plates. Between 2014 and 2020, 121 patients with Sanders type II calcaneus fractures were surgically treated in our group using K-wire (Group K: n = 31), CCS (Group C: n = 60) or plate (Group p: n = 30) fixation. We assessed the American Orthopedic Foot and Ankle Society (AOFAS) score and infection after operation as clinical outcomes and Böhler's and Preiss' angles as radiographic outcomes. The AOFAS scores of the 3 groups showed a significant difference, with Group P showing significantly inferior scores to Group C at 6 months postoperatively and at the final follow-up examination (p = .015 and p < .001, respectively). The rate of infection did not differ to a statistically significant extent, but the incidence in Group P tended to be higher in comparison to the other groups. Among the three groups, Böhler's angle did not differ to a statistically significant extent immediately after the operation (p = .113) or at the final follow-up examination (p = .383). Postoperatively, Preiss' angle did not differ to a statistically significant extent (p = .251) but was significantly smaller in the Group C at the final follow-up examination (p = .0331). In Sanders type II calcaneus fracture, CCS fixation may obtain the best functional outcomes.

Patient Reported Outcome Measures (PROMs) in Surgery: Evaluation after Minimally Invasive Reduction and Percutaneous K-Wires Fixation for Intra-Articular Calcaneal Fractures

Background: The optimal surgical treatment of intra-articular calcaneal fractures (IACF) is still under debate. In the literature, results are based on clinical or radiographical findings. Few studies have evaluated the effect of patient expectations on patient-reported outcomes after surgery and little is known about outcomes directly reported by the patient who experienced it. Patient reported outcome measures (PROMs) may represent a viable and useful tool for evaluating the efficacy of the procedure and can be considered as an indicators of health-care quality. The aim of this study is to evaluate PROMs after minimally invasive reduction and percutaneous Kirschner-wires fixation for IACF, and to compare PROMs to pre-operative and last follow-up radiographic findings. Methods: 33 consecutive patients with IACF treated with minimally invasive reduction and percutaneous K-wires fixation were included. Data collection included demographics, pre-operative and last available Böhler and Gissane angle X-rays, foot function index (FFI), and foot and ankle outcome score (FAOS). Results: At a mean follow up of 36.7 months, the mean FFI score was 24.3 ± 19.9 and the mean FAOS score was 68 ± 24.8. Patients with better Gissane angle showed better activity limitations FFI subscores. Moreover, worse pre-operative Gissane and Böhler angle were significantly associated with a worse total FAOS score and subscores. Conclusions: Minimally invasive reduction and percutaneous K-wires fixation provided satisfactory PROMs. Despite these results, prospective randomized studies are required to confirm the validity and reliability of PROMs in evaluating different treatments.

Consequences of extensile lateral approach to the calcaneal fractures on balance and isokinetic strength of muscle groups crossing the ankle joint

BACKGROUND

Inherent characteristics of extensile lateral approach (ELA) for fixation of displaced intraarticular calcaneal fractures together with delayed or probably insufficient physical therapy programs may lead to weakness of the muscle groups crossing the ankle joint. Peroneal tendons might be involved more than others because of possible postoperative adhesions. The aim of this study was to evaluate the isokinetic strength of the muscle groups crossing the ankle joint and also to assess balance and functional ability in this group of patients.

METHODS

Based on a pilot study, 23 patients undergone open reduction and internal fixation (ORIF) via ELA and 22 healthy subjects as the control group participated in this observational cross-sectional study. Patients more than 20 years of age with at least 12 months passed their unilateral closed intraarticular calcaneal fracture fixation without any postoperative complications like infection or wound dehiscence were included. Patients with history of concomitant lower extremity injury, spine trauma or surgery, cases underwent removal of calcaneal plates, and cases with neuromuscular or vestibular dysfunction were excluded. The outcome was assessed by isokinetic parameters such as peak torque, peak torque normalized to body weight, mean power and total work modified star excursion balance test, triple hop for distance test, and evertor-to-invertor (E/I) strength ratio. Isokinetic tests were performed at 60 and 120°/s.

RESULTS

Greater strength was observed in all muscles in the control group at 60°/s (p < 0.05). Evertors and invertors were weaker in the operated group at 120°/s in comparison to the dorsiflexors and plantarflexors. Modified star excursion (p: 0.003) and triple hop tests (p: 0.001) were lower in the operated group. E/I ratio was not statistically significant between the two groups at 60°/s (p: 0.44) and 120°/s (p: 0.62).

CONCLUSIONS

Strength deficit in all muscle groups crossing the ankle joint, and not evertors in isolation, in addition to balance and functional impairments would be seen one year following ORIF of calcaneal fracture via ELA. A long-term rehabilitation program emphasizing different kinds of contraction at low and high speeds and balance training in these patients is highly recommended.