An experimental study on the digital precision of internal fixation via the sinus tarsi approach for calcaneal fractures

The cadaveric research model for calcaneus fractures: A scoping review of biomechanical, anatomical, radiographic and fracture fixation studies

BACKGROUND

Calcaneal fractures remain a big challenge in orthopaedic surgery and lead to long lasting disabilities. Cadaveric research plays an important role in determining optimal fracture treatment. This scoping review aims to provide insight into cadaveric research that has been conducted on calcaneal fractures, including biomechanics, fixation, approaches and radiographic studies.

METHODOLOGY

A search strategy was created and implemented as per PRISMA guidance. 3 databases, Medline, Embase and Scopus, were used when conducting this review.

RESULTS

484 individual studies were retrieved across the 3 databases, of which 186 duplicates were excluded. Study abstracts were individually reviewed, of which 208 studies were excluded in accordance with study criteria. 90 papers were sought for retrieval, of which 83 full text papers were successfully retrieved. Of the full papers retrieved, 22 did not meet our inclusion criteria, and 19 papers related only to talus fractures. In the end, 43 cadaveric studies pertaining to this scoping review were included and reviewed.

DISCUSSION

Studies were grouped into biomechanical, anatomical, fixation and radiographic studies for review.

CONCLUSION

Evaluation of current cadaveric studies pertaining to calcaneal fractures has allowed greater insight into the myriad challenges in the management of these injuries. Effects of intra-articular fractures on calcaneal biomechanics assist in establishing surgical goals. Whilst fixation studies showing good stability of nail fixations could encourage further development in minimally invasive techniques. Avoiding pitfalls seen in the extensile lateral approach. Recommendations of areas for further research include use of external fixators, fixation in non-Sanders Type 2 fractures, and comparison of intraoperative CT/3D fluoroscopy with o conventional fluoroscopy.

Optimal posterior screw placement configuration in Sanders 2B calcaneal fractures: A biomechanical study

BACKGROUND

Calcaneal fractures can be high energy intra-articular injuries associated with joint depression. Challenges to fracture reduction include lateral wall blow out, medial wall overlap, comminution and central bone loss. Secondary deformity such as hindfoot varus alters foot biomechanics. Minimally invasive approaches with indirect reduction of the calcaneal tuberosity to maintain the reduction using posterior screws is routinely being used in the treatment of joint depression fractures. Biomechanically, optimum screw numbers and configuration is not known. Biomechanical studies have evaluated and proposed different screw configurations, however, it is not clear which configuration best controls varus deformity. This study aims to determine the optimum screw configuration to control varus deformity in Sanders 2B calcaneal fractures.

METHODS

Sawbone models were prepared to replicate Sanders type 2-B fracture, with central bone loss and comminution. 0.5 cm medial wedge of the calcaneal tuberosity was removed to create varus instability. After stabilising posterior facet with a single 4 mm partial threaded screw, and applied an 8 hole contoured plate to stabilise the angle of Gissane, inserted one or two 7 mm cannulated partially threaded Charlotte^TM (Wright Medical Technology, Memphis, USA) Headless Multi-use Compression (under image guidance) extra screws to control varus and subsidence deformity of the fracture. Coronal plane displacement of the dissociated calcaneal tuberosity fragment relative to the body when applying 5 N, 10 N and 20 N force was measured in millimetres (mm).

RESULTS

2 screws inserted (one medial screw into the sustentaculum talus from inferior to superior and, one lateral screw into the long axis anterior process) provides the least displacement (0.88 ± 0.390 at 5 N and 1.7 ± 1.251 at 20 N) and the most stable construct (p < 0.05) when compared to other configurations. A single medial screw into the sustentaculum tali (conf. 3) resulted in the least stable construct and most displacement (4.04 ± 0.971 at 5 N and 11.24 ± 7.590 at 20 N) (p < 0.05).

CONCLUSION

This study demonstrates the optimal screw configuration to resist varus in calcaneal fractures using minimally invasive techniques. Optimal stability is achieved using 2 screws; one located along the long axis of the calcaneus (varus control) and the other placed in the short axis directed towards the posterior facet of the calcaneus (control varus and subsidence). Further cadaver research would help evaluate optimal screw placement in simulated fractures to further assess reproducibility.

Optimal posterior screw placement configuration in Sanders 2B calcaneal fractures: A biomechanical study

BACKGROUND

Calcaneal fractures can be high energy intra-articular injuries associated with joint depression. Challenges to fracture reduction include lateral wall blow out, medial wall overlap, comminution and central bone loss. Secondary deformity such as hindfoot varus alters foot biomechanics. Minimally invasive approaches with indirect reduction of the calcaneal tuberosity to maintain the reduction using posterior screws is routinely being used in the treatment of joint depression fractures. Biomechanically, optimum screw numbers and configuration is not known. Biomechanical studies have evaluated and proposed different screw configurations, however, it is not clear which configuration best controls varus deformity. This study aims to determine the optimum screw configuration to control varus deformity in Sanders 2B calcaneal fractures.

METHODS

Sawbone models were prepared to replicate Sanders type 2-B fracture, with central bone loss and comminution. 0.5cm medial wedge of the calcaneal tuberosity was removed to create varus instability. After stabilising posterior facet with a single 4mm partial threaded screw, and applied an 8 hole contoured plate to stabilise the angle of Gissane, inserted one or two 7mm cannulated partially threaded Charlotte™ (Wright Medical Technology, Inc. 5677 Airline Road Arlington, TN) Headless Multi-use Compression (under image guidance) extra screws to control varus and subsidence deformity of the fracture. Coronal plane displacement of the dissociated calcaneal tuberosity fragment relative to the body when applying 5N, 10N and 20N force was measured in millimetres (mm).

RESULTS

2 screws inserted (one medial screw into the sustentaculum talus from inferior to superior and, one lateral screw into the long axis anterior process) provides the least displacement (0.88±0.390 at 5N and 1.7±1.251 at 20N) and the most stable construct (p<0.05) when compared to other configurations. A single medial screw into the sustentaculum tali (conf. 3) resulted in the least stable construct and most displacement (4.04±0.971 at 5N and 11.24±7.590 at 20N) (p<0.05).

CONCLUSION

This study demonstrates the optimal screw configuration to resist varus in calcaneal fractures using minimally invasive techniques. Optimal stability is achieved using 2 screws; one located along the long axis of the calcaneus (varus control) and the other placed in the short axis directed towards the posterior facet of the calcaneus (control varus and subsidence). Further cadaver research would help evaluate optimal screw placement in simulated fractures to further assess reproducibility.

Biomechanical testing of three coracoclavicular ligament reconstruction techniques with a 3D printing navigation template for clavicle-coracoid drilling

Background

The identification and precise clavicle-coracoid drilling during coracoclavicular (CC) ligament reconstruction for acromioclavicular (AC) joint dislocation require a high level of experience and surgical skills. Furthermore, the improvement of flexible fixation, such as Endobutton techniques for CC ligament reconstructions is ongoing. We have developed a 3D printing technique navigation template for clavicle-coracoid drilling and a novel implant for the reconstruction. This study aimed to determine the efficiency of the navigation template for clavicle-coracoid drilling and to evaluate the biomechanical performance of the novel CC ligament reconstruction technique.

Methods

A total of 24 fresh-frozen human cadaveric shoulders were randomly assigned to 1 of 3 reconstruction groups or a control group: TightRope, Triple Endobutton, and the Adjustable Closed-Loop Double Endobutton technique. Computed tomography scans, navigation template designs, and 3D printing were performed for the shoulders. Then, AC joint dislocation was simulated in the reconstruction groups, and 3 CC ligament reconstruction techniques were operated via the 3D printing template separately. Furthermore, biomechanical protocols including the translation test (load from 5 to 70 N) and the load-to-failure test were performed to characterize the behaviors and strengths. One-way ANOVA test analyzed differences in displacement under the translation load and the load at failure.

Results

CC ligament reconstructions were performed successfully along with the 3D printing navigation template in the 3 reconstruction groups. During the translation test, no significant difference was found in displacements among the 4 groups. Meanwhile, the mean load of all reconstruction groups at failure (Adjustable Closed-Loop Double Endobutton, 722.1620 N; TightRope, 680.4020 N; Triple Endobutton, 868.5762 N) was significantly larger than the control group (564.6264 N, P<0.05). The Triple Endobutton group had the maximum load at failure (P<0.05), however, no significant difference was noticed between the other 2 reconstruction groups (P>0.05).

Conclusions

The 3D printing navigation template may become helpful and reliable for AC joint dislocation surgery. Among the 3 CC ligament reconstruction techniques, the Triple Endobutton technique has the best strength in terms of biomechanics, while the biomechanical strength of the Adjustable Closed-Loop Double Endobutton technique is reliable in comparison with the TightRope technique.

Comparison of the modified sinus tarsi approach versus the extensile lateral approach for displaced intra-articular calcaneal fractures

Background

This study sought to assess and compare the clinical efficacy and complications of a modified sinus tarsi approach (MSTA) and the extensile lateral approach (ELA) in the treatment of displaced intra-articular calcaneal fractures.

Methods

This retrospective study enrolled 108 patients (117 feet) with Sanders II-IV calcaneal fractures, including 52 patients (56 feet) in the MSTA group and 56 patients (61 feet) in the ELA group. The functional and radiological results of the affected feet were analysed retrospectively. Functional evaluation included American Orthopaedic Foot and Ankle Society (AOFAS), visual analog scale (VAS), and Short Form-36 Health Survey (SF-36). Radiological evaluation included preoperative and postoperative changes in the Bohler Angle, Gissane Angle, length, width, and height of the calcaneus. The postoperative complications were also collected and analysed. The independent-samples t-test and analysis of variance (ANOVA) were employed to compare differences between the two groups. Differences within the same group were compared by paired Student's t-test, and categorical variables were compared using the chi-square test.

Results

The postoperative functional and radiological results showed that the mean AOFAS, VAS and physical component summary of SF-36 scores in the MSTA group were higher than those in the ELA group (P<0.05). After surgery, the Bohler and Gissane angles were significantly improved in both groups, as were the length, width, and height of the calcaneus; no statistically significant differences existed between the two groups. The incidences of wound healing complications and postoperative sural nerve injury were lower in the MSTA group than in the ELA group (P<0.000).

Conclusions

The MSTA can achieve similar effects to the ELA in terms of anatomical reconstruction and functional recovery. It also can also effectively reduce the incidences of wound healing complications and postoperative sural nerve injury, and shorten the length of hospital stay.