Biomechanical stability of intramedullary technique for fixation of joint depressed calcaneus fracture

Biomechanical comparison of screw position in variable angle locking plate in intra-articular calcaneal fractures: Cadaveric and radiologic study

BACKGROUND

Lateral plating of calcaneal fractures using variable-angle locking plates is still the golden standard for severely comminuted cases. The aim of this study is to explore the possibilities of improving stability of osteosynthesis by changing screw directions. It provides an assessment and comparison of cadaveric biomechanical experiment with retrospective radiologic data analysis.

METHODS

In the cadaveric study 8 intact calcaneus-talus specimens were obtained from 4 deceased donors. Fracture type 2b according to Sanders' classification was created in each specimen and fixed with variable-angle locking plate. The specimens were divided in 2 groups differing in orientation of anterior screws and fixed in PMMA base. A push-in test was performed by a two-column testing machine until gross failure. Retrospective cohort study was performed, reviewing data of 74 patients which underwent surgical treatment of calcaneal fractures with the same construct. Evaluation was performed at scheduled CT and X-Ray controls. Direction of inserted screws and implant failure were noted.

FINDINGS

The cadaveric study proved that there is no significant difference in mean failure force between two abovementioned screw configurations in Sanders 2b fracture. A significant difference was observed in initial stiffness. The radiologic retrospective study showed that difference in screw position within all fracture types but type 2b is significant.

INTERPRETATION

Screw configuration in the anterior part of variable-angle locking plate appears to affect primary stiffness and stability of the construct. Particularly in more comminuted fractures, screw inserted in the direction of sustentaculum improves the stability and lowers risk of implant failure.

Subtalar joint arthroscopic-assisted reduction and cannulated screw fixation versus open reduction and internal fixation for treating displaced intra-articular calcaneal fractures

BACKGROUND

The treatment of calcaneal fractures is not uniform. This study aimed to compare the functional and imaging results of subtalar joint arthroscopic reduction combined with cannulated screw fixation (SJACF) and the extended lateral approach (ELA) for the treatment of Sanders type II and III displaced intra-articular calcaneal fractures (DIACFs).

METHODS

From January 2020 to January 2023, 60 patients with calcaneal fractures were treated with SJACF or ELA for foot and ankle surgery at the Second Affiliated Hospital of Anhui Medical University. Changes in calcaneal Böhler's angle, the Gissane angle, and calcaneal length, height, and width were recorded before, after, and at the 1-, 3-, 6-, 12-month, and last follow-up. The preoperative waiting time, operation time, length of hospital stay, and other data of each patient were analyzed. The visual analogue scale (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) scores were used to evaluate clinical effects.

RESULTS

All 60 patients were followed up for at least 12 months. There was no statistical difference in baseline data (age, sex, fracture side, mechanism of injury, and classification) between groups (P > 0.05). The preoperative waiting time, length of hospital stay, and intraoperative fluoroscopy times were shorter in the SJACF group than in the ELA group; however, the operative time was greater in the SJACF group (P < 0.05). There were no significant differences in Böhler's angle, the Gissane angle, or calcaneal length, height, or width between the two groups at any time point (P > 0.05). These imaging values were significantly improved after surgery and at the last follow-up (P < 0.05). The VAS scores of the patients in the SJACF group were significantly different from those in the ELA group at the last follow-up (P < 0.05). The final AOFAS score and incidence of postoperative complications were better in the SJACF group; however, the difference was not significant (P > 0.05). Simultaneously, patients were able to return to work and achieve full weight-bearing earlier in the SJACF group (P < 0.05).

CONCLUSION

Both SJACF and ELA improved the clinical outcomes of patients with DIACFs. SJACF reduces surgical wounds and maintains effective reduction and strong internal fixation. It has the advantages of a reduced preoperative waiting time, shortened hospital stay, reduced intraoperative fluoroscopy time, alleviated postoperative pain, and accelerated patient recovery.

Sustentaculum fracture fixation with lateral plate or medial screw fixation are equivalent

BACKGROUND

Fixation of sustentaculum tali fractures is important to maintain the biomechanical function of the subtalar joint. A common method of fixation is securing the sustentacular fragment by way of a laterally based locking plate (LP). A medial approach with a single screw (MS) has been proposed as an alternative method of fixation.

METHODS

Five pairs of formalin-preserved cadaveric ankles with the subtalar joint and interosseous ligaments intact ("osseous cadavers") and four pairs of fresh-frozen cadaveric ankles with soft-tissue preserved dissected from mid-tibia down ("soft tissue cadavers") were used in the study. The left ankle was randomly assigned to one of the two fixation methods (LP or MS), while the right ankle was the opposite. These same steps for fixation were repeated for six synthetic ankle models. All models were loaded with a body mass of 80 kg. Statistical differences between LP and MS stiffness were determined using a paired t-test in cadavers and un-paired t-tests in synthetic ankles.

RESULTS

For osseous cadaveric ankles, LP demonstrated a mean stiffness of 232.95(SD: 59.96) N/mm, while MS was 239.72(SD:131.09) N/mm (p = 0.9293). For soft tissue cadaveric ankles, LP mean stiffness was 133.58(SD:37.84) N/mm, while MS was 134.88(SD:20.75) N/mm (p = 0.9578). For synthetic ankles, LP mean stiffness was 220.40(SD:81.93) N/mm, while MS was 261.50(SD:100.21) N/mm (p = 0.6116).

CONCLUSIONS

Across all three models, there was no significant difference between LP and MS methods. Retrospective observational studies are recommended to assess patient outcomes from each of the methods.

Comparison between screw fixation and plate fixation via sinus tarsi approach for displaced intra-articular calcaneal fractures: a systematic review and meta-analysis

BACKGROUND

Optimal surgical fixation for displaced intra-articular calcaneal fractures (DIACF) remains a subject of debate, particularly regarding the superiority between screw fixation and plate fixation via the sinus tarsi approach (STA). This review aims to determine the preferred treatment for DIACF and compare the outcomes of minimally invasive surgery options.

METHODS

Our study involved thorough searches across multiple electronic databases, including PubMed, Cochrane, Embase, and Web of Science, to identify all relevant publications on distal intra-articular fractures of the calcaneus (DIACFs) that were fixed using cannulated screws or plates via STA. Through a comprehensive meta-analysis, we evaluated several outcomes, including post-operative function, radiological measurements, and complications.

RESULT

A total of 728 patients from 7 studies met the inclusion criteria. Among them, 435 patients underwent screw fixation via STA, and 373 patients underwent plate fixation via STA. The study found no statistically significant differences between the screw fixation and the plate fixation via sinus tarsi approach (STA) in terms of AOFAS scores, Bohler's angle, Gissane's angle, sural nerve injury, secondary subtalar arthrodesis and reoperation. Compared with screw fixation, plate fixation via STA can reduce reduction loss of Bohler's angle (WMD = - 1.64, 95% CI = [- 2.96, - 0.31], P = 0.06, I2 = 59%), lower the incidence of fixation failure (OR = 0.32, 95% CI = [0.13, 0.81], P = 0.78, I2 = 0%), and decrease intra-articular step-off (WMD = - 0.52, 95% CI = [- 0.87, - 0.17], P = 0.66, I2 = 0%).

CONCLUSIONS

Plate fixation demonstrates superior capability in restoring calcaneal width, maintaining Bohler's angle, and minimizing intra-articular step-off, thereby maintaining better reduction of the subtalar articular surface. In addition, plate fixation exhibits the modest complication rate and a low incidence of fixation failure. Therefore, we recommend the use of plate fixation through the STA, especially for complex and comminuted intra-articular calcaneal fractures.

Emergency surgery of intra-articular calcaneal fractures using sinus tarsi approach with modified reduction technique

BACKGROUND

The purpose of this study was to evaluate emergency surgery of calcaneal fractures using the sinus tarsi approach (STA) with modified reduction technique in terms of complication rates, iconography results and functional outcome.

METHODS

We evaluated the outcomes of 26 patients treated in an emergency using STA with modified reduction technique. For that, we assessed Böhler´s angle, Gissane angle, reduction of the calcaneal body, and posterior facet, the visual analog scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) score, complications, preoperative time, operative time, and in-hospital time.

RESULTS

Recovery of calcaneal anatomy and articular surface were found at final follow-up. The mean Böhler´s angle at final follow-up were 30.68° ± 3.69°, of which was 15.02° ± 3.88° preoperatively (p < 0.001). The mean Gissane angle at final follow-up were 114.54° ± 11.16° of which was 88.86° ±10.96° preoperatively (p < 0.001). All cases had the varus/valgus angle of the tuber within 5 degrees. At the final follow-up, the mean AOFAS score was 89.23 ± 4.63, and the VAS score was 22.73 ± 6.5.

CONCLUSIONS

Emergency surgery using STA with modified reduction technique is reliable, effective, and safe for treatment of calcaneal fractures. This technique can bring good clinical outcomes and a low rate of wound complications, reducing the in-hospital time, costs, and accelerating rehabilitation.

Outcomes of Early Weight Bearing in Displaced Intra-articular Calcaneus Fractures Treated with Screws-Only Fixation Technique

Background

Displaced intraarticular calcaneus fracture indicates surgical treatment. The current trend is open reduction and internal fixation with a plate or multiple screws through the sinus tarsi approach. Most postoperative protocols are prolonged non-weight bearing that causes a high socioeconomic burden. This study aims to determine the safety of the early weight-bearing protocol of screws-only fixation in calcaneal fracture.

Materials and Methods

Evaluate displaced intraarticular calcaneus fractures treated with screws-only technique via the sinus tarsi approach in our institution. The first group, from July 2017 to December 2018, allowed patients to start partial weight bearing as tolerated at 4 weeks after surgery. The second group prospectively from January 2019 to March 2020, which assign patients to keep non-weight bearing for 8 weeks. The functional outcomes (Thai Foot and ankle ability measure subjective form, FAAM) were measured 6 months after surgery. The radiographic outcome (Bohler's angle and Gissane angle) was measured on the first day postoperative and 6 months follow-up, and the changes in these angles were recorded.

Results

There were 28 patients in each group. The outcomes were collected and compared by a T-test. In the early weight-bearing group, The FAAM, Bohler's angle loss, and Gissane's angle change were 76.4 ± 14.8, 2.4 ± 3.5, and 6.6 ± 7.8, respectively. In the delayed weight-bearing group, The FAAM, Bohler's angle loss, and Gissane's angle change were 81 ± 14.8, 2 ± 1.8 and 2.6 ± 6.1, respectively. There was no statistically significant difference in FAAM score, Bohler's angle loss, and Gissane's angle change between early and delayed weight-bearing groups.

Conclusion

Screws fixation in calcaneal fracture may be safe to allow early weight-bearing protocol.

Abordaje del seno del tarso para el tratamiento de las fracturas de calcáneo: una técnica de creciente difusión Maximiliano

Objetivo: Describir los resultados radiográficos y funcionales, y las complicaciones de la osteosíntesis de fracturas de calcáneo mediante el abordaje del seno del tarso. Materiales y Métodos: Se evaluaron 54 fracturas articulares de calcáneo desplazadas en 50 pacientes con radiografías de pie, de frente y de perfil, y tomografía computarizada preoperatorias. Se tomaron radiografías de pie, de frente y de perfil sin carga en el posoperatorio inmediato y con carga a las semanas 6 y 12, y al final del seguimiento. Se midió el ángulo de Böhler y se cuantificó el grado de artrosis subastragalina y calcaneocuboidea. Se determinó el puntaje de la AOFAS y se registraron las complicaciones de la herida, las lesiones neurológicas y la necesidad de cirugías adicionales, como retiro del material de osteosíntesis y artrodesis subastragalina. Resultados: El seguimiento fue de 30.8 meses. La serie estaba formada por 8 mujeres y 42 hombres, con una edad de 39.40 ± 14 años (rango 18-65). Cuarenta fracturas eran Sanders tipo II, 13 tipo III y 1 tipo IV. El puntaje de la AOFAS fue: excelente (12 casos), bueno (25 casos), regular (12 casos) y malo (5 casos). El ángulo de Böhler preoperatorio era de 10,8 ± 10,4° y 30,77 ± 8,24° al final del seguimiento (p <0,00001). El 3,7% tuvo complicaciones menores de la herida y el 5,6%, complicaciones mayores. Conclusión: El abordaje del seno del tarso permite una reducción aceptable con resultados buenos y excelentes en la mayoría de los pacientes y escasas complicaciones de partes blandas.

Can 3-Dimensional Printing for Calcaneal Fracture Surgery Decrease Operation Time and Improve Quality of Fracture Reduction?

We investigated whether 3-dimensional (3D) printed models can decrease operation time and improve the quality of reduction for calcaneal fractures. The study involved 48 patients with unilateral intra-articular calcaneal fractures, who were retrospectively case-matched according to Sander's classification, age, and sex. Group A (24 patients) was operated using 3D printed models as a preoperative and intraoperative tool, and group B (24 patients) was operated using standard techniques without 3D printed model. Operation time was significantly shorter for group A, compared to group B (82.3 ± 13.2 vs 91.4 ± 16.0, p = .036). The differences between the radiological parameters of operated calcaneus, compared to the normal side was similar between the 2 groups (Böhler angle, 5.3° ± 3.9° vs 4.2° ± 4.7°, p = .45, Gissane angle, 5.9° ± 12.5° vs 8.4° ± 11.0°, p = .54). The number of screws projecting more than 5 mm from the cortex was lower in group A than in group B (7/187, 4% vs 16/208, 8%, p = .11). The number of screw holes of the plate cut intraoperatively was significantly lower for group A compared to group B (1 vs 138). Although group A started weightbearing 3 to 4 weeks earlier than group B, the radiological parameters were similar between groups that early weightbearing was possible for group A using the 3D printed models (Böhler angle, - 1.5° ± 0.8° vs - 1.8° ± 1.2°, p = .28, Gissane angle, 2.5° ± 2.6° vs 3.5° ± 4.3°, p = .39). The operation time was shorter while using the 3D printed models, compared to that of the standard technique without using the 3D printed model. The radiological parameters were not statistically different, and the quality of fracture reduction seemed similar. However, with the use of 3D printed models, early weightbearing was possible without significant subsidence of reduced fragments or failure of fracture reduction, comparable to non-weightbearing cases.

Comminuted intraarticular calcaneal fractures: Multiplanar VA locked plating and interlocked nailing incorporate longitudinal strut and provide superior stability - a biomechanical cadaveric study

Treatment of comminuted intraarticular calcaneal fractures remains controversial and challenging. The aim of this study was to investigate the biomechanical performance of three different methods for fixation of such fractures. Comminuted calcaneal fractures, including Sanders III AB fracture of the posterior facet and Kinner II B fracture of the calcaneocuboid joint (CCJ) articular calcaneal surface, were created in 18 human cadaveric lower legs by osteotomizing. The ankle joint, medial soft tissues and midtarsal bones along with their ligaments were preserved. The specimens were randomized to three groups for fixation with either (1) 2.7 mm variable-angle locking lateral calcaneal plate (Group 1), (2) 2.7 mm variable-angle locking anterolateral calcaneal plate in combination with one 4.5 mm and one 6.5 mm cannulated screws (Group 2), or (3) interlocking calcaneal nail with 3.5 mm screws in combination with three separate 4.0 mm cannulated screws (Group 3). All specimens were biomechanically tested to failure under axial loading in midstance foot position. Each test commenced with a quasi-static compression ramp from 50 to 200 N, followed by progressively increasing cyclic loading at 2 Hz. Starting from 200 N, the peak load of each cycle increased at a rate of 0.2 N/cycle. Interfragmentary movements were captured by motion tracking. In addition, mediolateral X-rays were taken every 250 cycles with a triggered C-arm. Böhler angle after 5000 cycles (1200 N peak load) increased significantly more in Group 1 compared to both other groups (P ≤ 0.020). Varus deformation of 10° between the calcaneal tuberosity and the lateral calcaneal fragments was reached at significantly lower number of cycles in Group 1 compared the other groups (P ≤ 0.017). Both cycles to 10° plantar gapping between the anterior process and the calcaneal tuberosity fragments, and 2 mm displacement at the CCJ articular calcaneal surface revealed no significant differences among the groups (P ≥ 0.773). From a biomechanical perspective, treatment of comminuted intraarticular calcaneal fractures using anterolateral variable-angle locking plate with additional longitudinal screws or interlocked nail in combination with separate transversal screws provides superior stability as opposed to lateral variable-angle locked plating only.

Sinus Tarsi Approach With Percutaneous Screw Fixation for Intra-Articular Calcaneal Fractures

The aim of this study was to evaluate the outcomes of surgical treatment of intra-articular calcaneal fractures by using the sinus tarsi approach combined with percutaneous medial reduction by leverage technique and percutaneous screw fixation. We assessed the outcomes of 29 patients treated using sinus tarsi approach with percutaneous screw fixation. All patients were evaluated both clinically and radiologically. The Böhler and Gissane angle were evaluated postoperatively using radiographs. During the median follow-up period of 27.0 ± 10.3 months, no cases with failure to reduce or displace hardware were detected. All cases achieved the restoration of a normal Böhler and Gissane angle. The median preoperative Böhler angle was 12.3° ± 2.5° while postoperatively it was 30.5° ± 5.7° (p < .01). The median preoperative Gissane angle was 98.1° ± 7.5°, which was 125.9° ± 3.6° postoperatively (p < .01). At the last follow-up, the median American Orthopedic Foot and Ankle Society hindfoot score was 87.7 ± 5.9, and the median Maryland foot score was 88.6 ± 5.9. Our technique for intra-articular calcaneal fractures can effectively correct calcaneal tuberosity outward displacement, medial wall overlapping, and the hindfoot varus deformity with less soft tissue damage. This technique is a good alternative for the treatment of calcaneal fractures, resulting in minimal soft tissue damage, few wound complications, and excellent radiological and clinical outcomes.

Percutaneous fixation of intraarticular joint-depression calcaneal fractures with different screw configurations - a biomechanical human cadaveric analysis

PURPOSE

The aim of this study was to assess the biomechanical performance of different screw configurations for fixation of Sanders type II B joint-depression calcaneal fractures.

METHODS

Fifteen human cadaveric lower limbs were amputated and Sanders II B fractures were simulated. The specimens were randomized to three groups for fixation with different screw configurations. The calcanei in Group 1 were treated with two parallel longitudinal screws, entering superiorly the Achilles tendon insertion, and two screws fixing the intraarticular posterior facet fracture line. In Group 2 two screws entered the tuberosity inferiorly to the Achilles tendon insertion and two transverse screws fixed the posterior facet. In Group 3 two screws were inserted along the bone axis, one transverse screw fixed the posterior facet and one oblique screw was inserted from the posteroplantar part of the tuberosity supporting the posterolateral part of the posterior facet. All specimens were biomechanically tested to failure under progressively increasing cyclic loading.

RESULTS

Initial stiffness did not differ significantly between the groups, P = 0.152. Cycles to 2 mm plantar movement were significantly higher in both Group 1 (15,847 ± 5250) and Group 3 (13,323 ± 4363) compared with Group 2 (4875 ± 3480), P ≤ 0.048. No intraarticular displacement was observed in any group during testing.

CONCLUSIONS

From a biomechanical perspective, posterior facet support by means of buttress or superiorly inserted longitudinal screws results in less plantar movement between the calcaneal tuberosity and the anterior fragments. Inferiorly inserted longitudinal screws are associated with bigger interfragmentary movements.

Articular calcaneal fractures: open or minimally invasive surgery, when the medial wall reduction is obtained percutaneously from the lateral side

PURPOSE

The purpose of this study was to compare the clinical outcomes of intra-articular calcaneal fractures with medial column displacement treated with different surgical techniques, namely extensile lateral approach (ELA) or sinus tarsi approach (STA), combined with percutaneous medial reduction.

METHODS

Ninety-six patients with intra-articular calcaneal fractures who were subjected to ELA or STA (45 in STA group and 51 in ELA group) were retrospectively assessed. Reduction of the posterior facet, calcaneal body, Böhler's angle, and Gissane's angle were evaluated. Clinical outcomes were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score and visual analog scale (VAS). The complications, time to surgery, operative time, and blood loss were also assessed.

RESULTS

Incidence of wound complications, post-operative blood drainage, and time to the operation were significantly different between the two groups. There was no significant difference in the recovery of calcaneal anatomy and articular surface between the two groups. Similarly, no difference was detected in Böhler's and Gissane's angles between ELA and STA groups (P > 0.05). Finally, there was no difference in AOFAS and VAS scores between the two groups at the final follow-up (P > 0.05).

CONCLUSION

STA resulted in favourable radiological and clinical results with fewer wound complications and a shorter waiting time when compared to ELA. The percutaneous medial reduction technique is effective in reducing medial column displacement.

Comparing less invasive plate fixation versus screw fixation of displaced intra-articular calcaneus fracture via sinus tarsi approach

PURPOSE

The purpose of this study was to compare the post-operative radiographic and clinical outcomes of less invasive plate fixation versus screw fixation of displaced intra-articular calcaneus fractures (DIACFs) via sinus tarsi approach.

METHODS

A total of 165 consecutive DIACFs that underwent open reduction internal fixation via sinus tarsi approach from 2013 to 2018 were reviewed at least a two year follow-up. The methods of fixation were divided into two groups: less invasive plate fixation versus screw fixation of calcaneus fracture (59 vs 106, respectively). The radiographic outcomes including pre- and post-operative Bohler's and Gissane's angles were evaluated. The post-operative function was evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score, the Olerud and Molander Scale and the Visual Analogue Scale (VAS). The complications, the rates of implant removal and cost were also compared.

RESULTS

The average follow-up was 44.2 months in the plate groups and 47.9 months in the screw groups (P > 0.05). There was no significant difference in the Bohler's angle and Gissane's angle between the plate group and screw group during the pre-operation and the last follow-up. There was no significant difference in the final AOFAS score, Olerud and Molander score and VAS score between the two groups (P > 0.05). The total incidence of complications was 6.7% in the plate group and 6.6% in the screw group (P > 0.05). The rates of implant removal and total cost during the hospitalization in the plate group were significantly higher compared with screws group (P < 0.05).

CONCLUSION

The less invasive plate fixation versus screw fixation of DIACFs via sinus tarsi approach contributed comparable quality of reduction, complications and post-operative functional outcomes. The less invasive plate technique was significantly higher in terms of implant costs and the rate of implant removal.

Stress shielding analysis on easy step staple prosthesis for calcaneus fractures

Objective

The calcaneus is the most frequently injured tarsal bone, with calcaneal fractures meaning that 60% of the fractures affect the foot and about 1%-2% of all fractures.

Methods

Two 3D FE model of the foot were realized in order to compare the stress shielding occurring in a health foot and in a fractured one implanted with an easy step prosthesis by Stryker. This dispositive is indicated for calcaneus fractures.

Results

Results evidence the efficacy of this kind of prosthesis as the Eq. Von mises stresses are comparable in the two model. Higher concentration of stress are concentered on the Easy step.

Conclusion

In conclusion, the easy step staple prosthesis allows obtaining excellent results in terms of calcaneus fracture treatments. The correct implant size for a given patient can be determined by evaluating the patient's height, weight, functional demands and anatomy.

Three-dimensional computed tomography analysis and functional results of calcaneal fractures treated by an intramedullary nail

BACKGROUND

Intramedullary calcaneal nailing is used to treat displaced intra-articular calcaneal fractures. The main goal of the study was to assess the reduction of tomography and secondary goals were patient functional scores and complication rates.

METHODS

The functional outcome and restoration of the radiographic parameters were evaluated post-operatively, at three months, at one year, and at the last follow-up. The morphology of the posterior facet was evaluated post-operatively, at one year and at the last follow-up by CTs.

RESULTS

Twenty-six patients were included. The mean follow-up was 2.8 years. The mean AOFAS-AHS was 79 at the last follow-up. The mean calcaneal height index and length rose respectively from 0.44 to 0.86 and 83 to 87 mm, and the width decreased from 50 to 46 mm.

CONCLUSION

The radiographic parameters were restored. The AOFAS-AHS was comparable with other series. This study confirms the efficiency of this procedure with lower rate of complications.

Reduction and functional outcome of open reduction plate fixation versus minimally invasive reduction with percutaneous screw fixation for displaced calcaneus fracture: a retrospective study

Background

Minimally invasive surgery has become popular because of the lower incidence of wound complications. However, achieving an anatomic reduction that provides a satisfactory outcome is difficult using minimally invasive surgery. Our study aimed to evaluate the reduction and clinical outcomes of closed reduction and percutaneous fixation treatment using a closed reduction traction device for displaced intra-articular calcaneal fractures compared with traditional open reduction plate fixation using an extended lateral approach.

Methods

A total of 40 patients and 45 feet with calcaneus fractures from 2012 to 2016 were studied. The open reduction plate fixation group (24 feet) was compared to the closed reduction percutaneous fixation group (21 feet) with a traction device. The reduction assessments included length, width, height, Bohler’s angle, Gissane’s angle, and varus or valgus angle before and after surgery. The clinical outcomes included the American Orthopaedic Foot and Ankle Society hindfoot score and the visual analog score for pain, length of stay, and complication rate.

Results

The patients were followed up for an average of 16.53 ± 3.95 months. No significant differences in reduction were observed between the open and closed groups (P > 0.05). The American Orthopaedic Foot and Ankle Society scores of the two groups were 80.29 ± 6.15 and 83.62 ± 6.95 (open versus closed) (P = 0.0957). The visual analog scores of the open and closed groups were 1.50 ± 1.22 and 0.81 ± 0.87 (P = 0.0364). The lengths of stay in the open and closed groups were 9.63 ± 2.72 days and 6.71 ± 1.85 days (P = 0.0002). The complication rates of the open and closed groups were 20.8% (5/24) and 4.8% (1/21) (P < 0.0001).

Conclusions

The closed reduction percutaneous fixation with traction device method may provide equivalent reduction results and superior outcomes for the length of stay, VAS score, and complication rate for displaced intra-articular calcaneal fractures.

Sinus Tarsi Approach with Screws-Only Fixation for Displaced Intra-Articular Calcaneal Fractures

Treatment of displaced intra-articular calcaneal fractures has changed numerous times in the last decades. Currently, less invasive surgery has reemerged and is increasingly used. The sinus tarsi approach is most commonly used. It combines the open approach to the subtalar joint with percutaneous reduction of the overall shape of the calcaneus. The results in the literature show overall similar functional outcome compared with the extended lateral approach, however with a significant reduction in wound complications. This article deals with the sinus tarsi approach in which the reduction is fixated using screws only. Indications, surgical technique, and possible pitfalls are discussed.

Screw tip augmentation leads to improved primary stability in the minimally invasive treatment of displaced intra-articular fractures of the calcaneus: a biomechanical study

PURPOSE

To investigate if the stability of minimally invasive screw osteosynthesis of displaced intra-articular calcaneal fractures (DIACF) can be effectively increased by an innovative approach to screw tip augmentation.

METHODS

In eight-paired human cadaver hindfoot specimens, DIACF of Sanders type IIB were treated with either standard screw osteosynthesis or with bone cement augmentation of the screw tips in the main fragments. The instrumented specimens were subjected to a cyclic loading protocol (9000 cycles, with stepwise increasing loads, 100-1000 N). The interfragment motions were quantified as tuber fragment tilt (TFT) and posterior facet inclination angle (PFIA) using a 3-D motion analysis system. Böhler's angle (BA) was evaluated from X-rays. A load-to-failure test was performed after the cyclic loading protocol.

RESULTS

All but one specimen of the augmented group withstood more cycles than the respective specimens of the non-augmented group. Mean cycles to failure for the failure criterion of 5° TFT were 7299 ± 1876 vs. 3864 ± 1810, corresponding to loads of 811 N ± 195 vs. 481 N ± 180, (P = 0.043). There were no significant differences observed in the PFIAs. The failure criterion of 5° BA was reached after a mean of 7929 cycles ± 2004 in the augmented group and 4129 cycles ± 2178 in the non-augmented group, corresponding to loads of 893 N ± 200 vs. 513 N ± 218, (P = 0,090). The mean load-to-failure of the four specimens in the augmented group that completed the cyclic loading was 1969 N over a 1742-2483 N range.

CONCLUSION

Screw tip augmentation significantly improved the mechanical stability of the calcanei after osteosynthesis in terms of decreased tuber fragment tilts and less changes in Böhler's angle.

Fixation Methods for Calcaneus Fractures: A Systematic Review of Biomechanical Studies Using Cadaver Specimens

Calcaneal fractures are notoriously difficult to treat and wound complications occur often. However, owing to the rare nature of these fractures, clinical trials on this subject are lacking. Thus, biomechanical studies form a viable source of information on this subject. With our systematic review of biomechanical studies, we aimed to provide an overview of all the techniques available and guide clinicians in their choice of method of fracture fixation. A literature search was conducted using 3 online databases to find biomechanical studies investigating methods of fixation for calcaneal fractures. A total of 14 studies investigating 237 specimens were identified. Large diversity was found in the tested fixation methods and in the test setups used. None of the studies found a significant difference in favor of any of the fixation methods. All tested methods provided a biomechanically stable fixation. All the investigated methods of fixation for calcaneal fractures seem to be biomechanically sufficient. No clear benefit was found for locking plates in the fixation of calcaneal fractures; however, a subtle mechanical superiority might exist compared with nonlocking plates in the case of fractures in osteoporotic bone. Several of the techniques tested would be suitable for a minimal invasive approach. These should be investigated further in clinical trials.

The primary stability of different implants for intra-articular calcaneal fractures: an in vitro study

Background

Calcaneal fractures account for around 2% of all fractures and most of them are intra-articular fractures. Many implants have been used in the fixation of calcaneal fractures, but their biomechanical stability has not yet been well investigated. The aim of this study was to compare the primary stability of four fixations of calcaneal fracture.

Methods

Eight cadaveric calcaneus samples were used to simulate the Sanders’ types III fracture pattern and fixed through four different implants, namely, K-wires, cannulated screws (CS), absorbable screws (AS), and plate-screw system (PSS). Each specimen was then placed into a custom-made jig and was loaded through a material testing machine to simulate the physiological condition. The primary stability was measured in the vertical direction as the stiffness and anterior–posterior direction as the calcaneocuboid force. One-way analysis of variance was used for data analysis.

Results

The results showed the highest stiffness of 634 (383–891; SD 226) N/mm in the intact model. It was significantly higher than the models fixed with K-wires, CS or PSS. There was no significant difference in vertical stiffness between fractures fixed with AS and the intact model or other fixed models. The intact model showed the lowest calcaneocuboid force of 153 (120–218; SD 39) N, while the fractures fixed with AS showed the greatest force of 242 (146–398; SD 84) N. The significance was only detected between these two models.

Conclusions

The global stiffness was similar when the calcaneal fractures were fixed by K-wires, CS and PSS. The stability of the AS fixation differed along both the vertical and anterior–posterior directions, and was greatly influenced by the bone quality. AS for fracture fixation should be designed with greater strength and pull-out resistance.

Surgical Treatment of Sanders Type 2 Calcaneal Fractures Using a Sinus Tarsi Approach

BACKGROUND

Calcaneum is the most commonly fractured tarsal bone. The optimal treatment for displaced calcaneus fractures involving the posterior facet is surgical. The extensile lateral approach is commonly preferred because it provides sufficient exposure of the subtalar facet. However, this technique has the risk of complications such as wound necrosis and sural nerve injury. Various minimally invasive approaches, such as sinus tarsi approach, limited posterior approach, and percutaneous approach, have been introduced to reduce possible complications. This study was prospectively performed to evaluate the results of the sinus tarsi approach for Sanders Type 2 calcaneal fractures using postoperative computed tomography (CT).

MATERIALS AND METHODS

Between October 2012 and December 2013, 20 Sanders Type 2 calcaneal fractures were consecutively treated using a sinus tarsi approach and checked using CT preoperatively, immediately postoperatively, and at 12 months after surgery. Clinical evaluations were performed using the visual analog scale (VAS) and the ankle-hindfoot score developed by the American Orthopaedic Foot and Ankle Society (AOFAS). Radiographic evaluations were performed using calcaneus lateral and axial radiographs, hindfoot alignment radiograph, and CT. Changes in Böhler's angles and calcaneal widths were evaluated both preoperatively and at last followup. Reduction of the posterior facet was graded according to articular step, defect, and angulation of the posterior facet in CT.

RESULTS

VAS and AOFAS scores were significantly improved at 1 year after surgery but did not improve further. Böhler's angles and calcaneal widths were significantly improved after surgery. Böhler's angle was significantly smaller at the last followup than immediately after surgery, whereas calcaneal width was maintained. Reduction of the posterior facet was graded excellent in five feet (25%), good in ten (50%), and fair in five (25%) on immediately postoperative CT. Two feet (10%) had transient sural nerve injury which resolved within 3 months. Five feet (20%) had subfibular pain due to a prominent screw heads.

CONCLUSION

Surgical management using a sinus tarsi approach produced good clinical and radiographic results and low wound complications for Sanders type 2 calcaneal fractures. It is important to have stable fixation and to achieve sufficient reduction of calcaneal width for the prevention of loss of reduction and lateral subfibular impingement.

Biomechanical comparison of locking plate and crossing metallic and absorbable screws fixations for intra-articular calcaneal fractures

The locking plate and percutaneous crossing metallic screws and crossing absorbable screws have been used clinically to treat intra-articular calcaneal fractures, but little is known about the biomechanical differences between them. This study compared the biomechanical stability of calcaneal fractures fixed using a locking plate and crossing screws. Three-dimensional finite-element models of intact and fractured calcanei were developed based on the CT images of a cadaveric sample. Surgeries were simulated on models of Sanders type III calcaneal fractures to produce accurate postoperative models fixed by the three implants. A vertical force was applied to the superior surface of the subtalar joint to simulate the stance phase of a walking gait. This model was validated by an in vitro experiment using the same calcaneal sample. The intact calcaneus showed greater stiffness than the fixation models. Of the three fixations, the locking plate produced the greatest stiffness and the highest von Mises stress peak. The micromotion of the fracture fixated with the locking plate was similar to that of the fracture fixated with the metallic screws but smaller than that fixated with the absorbable screws. Fixation with both plate and crossing screws can be used to treat intra-articular calcaneal fractures. In general, fixation with crossing metallic screws is preferable because it provides sufficient stability with less stress shielding.

Functional outcome of displaced intra-articular calcaneal fractures: a comparison between open reduction/internal fixation and a minimally invasive approach featured an anatomical plate and compression bolts

BACKGROUND

The purpose of this study is to assess the clinical results of a minimally invasive treatment featured the concept of internal compression, including an anatomic plate and multiple compression bolts compared with open reduction and internal fixation for displaced intra-articular calcaneal fractures (DIACFs).

METHODS

We retrospectively analyzed 329 patients (383 feet) who were identified from trauma inpatient database in our hospital for DIACFs from January 2004 to December 2009. Of them, 148 patients (170 feet) were treated with open reduction and internal fixation (OR group), which involved using a traditional L-shaped extended lateral approach, and fractures were fixed by plate and screws from January 2004 to December 2006; 181 patients (213 feet) were treated with a minimally invasive approach featured the concept of calcaneal internal compression (CIC group), which was achieved by an anatomic plate and multiple compression bolts through a small lateral incision from January 2007 to December 2009. Postoperative complications were recorded. During follow-up, pain and functional outcome were evaluated with the American Orthopaedic Foot and Ankle Society (AOFAS) scores and compared between the two groups. Subsequent subtalar arthrodesis and early implant removal were performed when indicated. Routine hardware removal was scheduled for all patients at 1-year follow-up.

RESULTS

There were no significant differences in sex, age, and fracture classification (Sanders classification) between the two groups. Wound healing complications were 4 of 213 (1.88%) in CIC group and 20 of 170 (11.76%) in OR group. Subtalar arthrodesis had to be performed in one case in OR group. Four cases in CIC group and four cases in OR group had the hardware removed earlier due to complications. The average time after surgery to start weight-bearing exercise is 5.64 weeks in CIC group and 9.38 weeks in OR group (p < 0.001). The mean AOFAS score is higher in CIC group than in OR group, although the difference is not statistically significant (87.53 vs. 84.95; p = 0.191). The overall results according to the AOFAS scoring system were good or excellent in 185 of 213 (86.85%) in CIC group and 144 of 170 (84.71%) in OR group. The subjective portion of the AOFAS survey answered by patients showed statistically significant difference in activity limitation and walking surface score (7.31 vs. 7.02 and 3.72 vs. 3.42; p < 0.05) but not in pain and walking distance between the two groups (32.72 vs. 32.29 and 4.37 vs. 4.42; p > 0.05).

CONCLUSION

The study results suggest that this minimally invasive approach featured the concept of the calcaneal internal compression can achieve functional outcome as good as, if not better than the open techniques. It is proved to be an effective alternative treatment for DIACFs.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Mini-open sinus tarsi approach with percutaneous screw fixation of displaced calcaneal fractures: a prospective computed tomography-based study

BACKGROUND

Open reduction and internal fixation (ORIF) of calcaneal fractures using an extended lateral approach results in soft tissue disruption and theoretically subtalar joint stiffness. A minimally invasive sinus tarsi approach for posterior facet exposure and percutaneous screw fixation of the calcaneal body has been implemented. This report details the reduction and stability of the internal fixation resulting from this approach.

METHODS

Twenty-one consecutive patients (18 male, 3 female, 45 ± 16 years) with 22 calcaneal fractures underwent ORIF with minimal exposure through the sinus tarsi for reduction, lateral plate fixation, and percutaneous screw fixation. There were nine Sanders type II fractures and 13 type III fractures. Sixteen fractures had calcaneocuboid joint involvement. Nineteen patients (19 fractures) were available for follow-up (mean, 32 ± 14 months). Two computed tomography scans were obtained on each patient, one immediately postoperatively and one after a minimum of 1 year, to evaluate reduction and fixation stability, respectively. The posterior facet and calcaneocuboid joint were graded excellent, good, fair, or poor, according to articular step, defect, and angulation. Any change was considered loss of stability. Similarly, on a conventional two-dimensional radiograph, more than 5° of Bohler's angle difference was defined as loss of calcaneal height.

RESULTS

Postoperative posterior facet and calcaneocuboid joint reduction was good (step < 1 mm, defect < 5 mm, angulation < 5°) or excellent (no step, defect, angulation) in 14/22 (64%) and 11/16 fractures, respectively. At follow-up, no loss of reduction at the posterior facet and calcaneocuboid joint was noted. More than 5° of Bohler's angle decrease was found in three patients.

CONCLUSION

Even complex calcaneal fractures can be sufficiently exposed by a minimally invasive sinus tarsi approach for anatomic reduction and stable fixation. Most patients had good or excellent functional results, which may have resulted from minimal soft tissue disruption.