Three-step closed reduction and percutaneous screw fixation: A reliable and reproducible protocol in managing displaced intra-articular calcaneal fractures

Finite element analysis of restoring length with multiple internal fixations in calcaneal body fracture

Calcaneal body fractures are often associated with varying degrees of shortening deformities. Restoring calcaneal length is crucial for the functional prognosis of the foot. Through finite element analysis, this study compared the biomechanical effects of multiple fixation schemes for calcaneal fractures. We delineated and assembled the finite element model of the Sanders type II calcaneal fracture and four internal fixation simulations (namely distraction screw, lag screw, frame locking plate, and T-shaped locking plate). Different axial forces (350, 700, and 1400 N) were then applied to simulate various postures. We then compared the inner and outer shortening distances (D1 and D2, respectively), equivalent von Mises stress, and maximum von Mises stress of the calcaneus. In the individual model, with an increase in the pressure, D1, D2, and the maximum von Mises stress gradually increased. At 1400 N, D1 and D2 for the internal fixation schemes were as follows: distraction screw (0.03 mm, 0.1 mm) < T-shaped locking plate (0.45 mm, 0.26 mm) < frame locking plate (0.50 mm, 0.26 mm) < lag screw (0.66 mm, 0.64 mm). The maximum von Mises stress values for the internal fixation methods were as follows: lag screw (491.0 MPa) < distraction screw (663.1 MPa) < frame locking plate (772.7 MPa) < T-shaped locking plate (931.8 MPa). In patients with calcaneal body fractures, the distraction screw is a potential therapeutic option for resisting calcaneal shortening.

Minimally Invasive Treatment of Inversion Shortening Calcaneal Fractures in the "Out-In" Position

OBJECTIVE

Heel fractures need extensive surgical incisions and are challenging to successfully reposition using traditional prying. The goal of this study is to evaluate the clinical effectiveness of using a Kirschner pin-guided distractor to treat inversion shortening calcaneal fractures in the "out-in" position.

METHODS

A total of 40 data from 37 patients with inversion shortened calcaneal fractures from January 2018 to March 2020 were reviewed. Preoperative lateral and axial X-rays and 3D CT were taken to assess the fracture type, and minimally invasive internal fixation was performed in the "out-in" position with distractor repositioning, and intraoperative and postoperative images were taken to assess fracture repositioning and fixation. During the follow-up period, the postoperative functional recovery status was assessed using the VAS score, AOFAS score, and FAOS score. Paired-samples t-test was used for all data comparisons.

RESULTS

All cases received a mean follow-up of 28.49 ± 3.25 months, and the mean fracture healing time was 7.84 ± 0.71 weeks. The postoperative images showed well-fixed fracture repositioning, and calcaneal height, length, width, and inversion angles were significantly improved. At the final follow-up, the calcaneal height, length, and width recovered from 39.35 ± 4.44mm, 79.35 ± 2.7mm, and 45.75 ± 2.87mm preoperatively to 50.93 ± 3.18mm, 82.23 ± 1.90mm, and 39.67 ± 1.58mm postoperatively (p < 0.001; p < 0.001; p < 0.001). The calcaneus inversion angle restored from 7.73° ± 2.26° to 3.80° ± 1.80° (p < 0.001). Böhler's angle and Gissane's angle improved from 13.13° ± 3.02° and 105.15° ± 8.94° to 27.95° ± 3.41° and 122.85° ± 5.54° (p < 0.001; p < 0.001). No non-healing fractures, osteomyelitis, or traumatic arthritis were observed.

CONCLUSION

Minimally invasive internal fixation with distractor repositioning in the "out-in" position is effective in the treatment of inversion shortening calcaneal fractures while restoring the anatomy and protecting the soft tissue.

Finite element analyses of three minimally invasive fixation techniques for treating Sanders type II intra-articular calcaneal fractures

BACKGROUND AND OBJECTIVE

Calcaneal Sanders type II or III fractures are highly disabling with significant burden. Surgical treatment modalities include open reduction and internal fixation (ORIF) techniques and a variety of minimally invasive surgical (MIS) approaches. ORIF techniques are associated with complications and traditional MIS techniques need extensive intraoperative fluoroscopic procedures. The present study aims to investigate the effects of three different minimally invasive internal fixation (MIIF) techniques used to treat Sanders type II intra-articular calcaneal fractures using finite element analyses.

METHODS

A 64-row spiral computed tomography scan was used to observe the calcaneus of a healthy adult. The scanning data were imported into Mimics in a DICOM format. Using a new model of a Sanders type II-B intra-articular calcaneal fracture, three minimally invasive techniques were simulated. Technique A involved fixation using an isolated minimally invasive locking plate; Technique B used a minimally invasive locking plate with one medial support screw; and Technique C simulated a screw fixation technique using four 4.0-mm screws. After simulating a 640-N load on the subtalar facet, the maximum displacement and von Mises stress of fragments and implants were recorded to evaluate the biomechanical stability of different fixation techniques using finite element analyses.

RESULTS

After stress loading, the maximum displacements of the fragments and implants were located at the sustentaculum tali and the tip of sustentaculum tali screw, respectively, in the three techniques; however, among the three techniques, Technique B had better results for displacement of both. The maximum von Mises stress on the fragments was < 56 Mpa, and stress on the implants using the three techniques was less than the yield strength, with Technique C having the least stress.

CONCLUSION

All three techniques were successful in providing a stable fixation for Sanders type II intra-articular calcaneal fractures, while the minimally invasive calcaneal locking plate with medial support screw fixation approach exhibited greater stability, leading to improved enhancement for the facet fragment; however, screw fixation dispersed the stress more effectively than the other two techniques.

3D simulation of percutaneous sustentaculum tali screw insertion in calcaneal fractures

BACKGROUND

In calcaneal fractures, the percutaneous screw fixation (PSF) is currently considered to be the better choice, but it is difficult to accurately place the screw into the sustentaculum tali (ST) during the operation. In this study, the ideal entry point, angle, diameter and length of the screw were calculated by simulating the operation process.

METHODS

We retrospectively collected the calcaneus computed tomography (CT) scans of 180 adults, DICOM-formatted CT-scan images of each patient were imported into Mimics software to establish calcaneus model. Virtual screws were placed on the lateral of the posterior talar articular surface (PTAS), the lateral edge of the anterior process of calcaneus (APC), and the calcaneal tuberosity, respectively, the trajectory and size of the screws were calculated.

RESULTS

The mean maximum diameter of the PTAS screw was 42.20 ± 3.71 mm. The vertical distance between the midpoint of the APC optimal screw trajectory and the lowest point of the tarsal sinus was 10.67 ± 1.84 mm, and the distance between the midpoint of the APC optimal screw trajectory and the calcaneocuboid joint was 5 mm ~ 19.81 ± 2.08 mm. The mean maximum lengths of APC screws was 44.69 ± 4.81 mm, and the Angle between the screw and the coronal plane of the calcaneus from proximal to distal was 4.72°±2.15° to 20.52°±3.77°. The optimal point of the maximum diameter of the calcaneal tuberosity screw was located at the lateral border of the achilles tendon endpoint. The mean maximum diameters of calcaneal tuberosity screws was 4.46 ± 0.85 mm, the mean maximum lengths of screws was 65.31 ± 4.76 mm. We found gender-dependent differences for the mean maximum diameter and the maximum length of the three screws.

CONCLUSIONS

The study provides effective positioning for percutaneous screw fixation of calcaneal fractures. For safer and more efficient screw placement, we suggest individualised preoperative 3D reconstruction simulations. Further biomechanical studies are needed to verify the function of the screw.

A prospective comparative study between percutaneous cannulated screws and Kirschner wires in treatment of displaced intra-articular calcaneal fractures

Purpose

Several minimally invasive procedures were used to treat displaced intra-articular calcaneal fractures (DIACFs). No agreement among different authors about either the ideal fixation method or which technique is minimally invasive. The aim of this study was to compare functional and radiographic outcomes of two minimally invasive techniques in treatment of Sanders type II and III DIACFs by using K-wires or cannulated screws without bone grafts.

Methods

A prospective randomized controlled study was conducted on 28 patients (34 feet) with Sanders type II or III DIACFs, treated by closed reduction and fixation using cannulated screws or K-wires, at the Orthopedics Department of Sohag University Hospital, between April 2020 and February 2022. Functional assessment was done by American Orthopedic Foot and Ankle Society (AOFAS) score and VAS for pain. Radiographic assessment was done by measurement of three calcaneal angles (Gissane, Böhler’s, and posterior facet inclination angles) and three calcaneal distances (height, length, and width of the calcaneus).

Results

Mean ages of patients at the time of operation were 34.8 years for the cannulated screw group and 36.6 years for the K-wire group. A vast majority of patients were males (78.6%). Involvement of the right side in the cannulated screw group was 57.1% and that in the K-wire group was 47.9%. Mean operative time was significantly shorter among the K-wire group (42 min) compared to the cannulated screw group (57 min). Mean AOFAS score was higher among the cannulated screw group (85.9 points) compared to the K-wire group (75.8 points). Final VAS was significantly better among the cannulated screw group compared to the K-wire group. Mean time of radiographic union in the cannulated screw group was 8.9 weeks and that in the K-wire group was 10.1 weeks.

Conclusion

Both techniques avoided wound complications associated with ORIF with the advantage of a shorter hospital stay. Patients in the cannulated screw group had better functional and radiographic outcomes and a lower rate of subtalar arthritis than patients in the K-wire group. K-wires had advantages of reduced operative time, and easy removal as an outpatient procedure.