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Background: Standard open calcaneal osteotomies to correct hindfoot malalignment have been associated with high complication rates, including nerve damage and wound infection. This has resulted in the development of minimally invasive techniques such as the percutaneous endoscopically assisted calcaneal osteotomy (PECO), which in cadaver studies has been shown to be potentially safer than open surgeries. The aim of this study was to demonstrate the safety and effectiveness of PECO in a clinical setting, with regard to neurovascular injury rates, infection, and short-term radiographic and functional outcomes. Methods: Forty-one (41) patients with planovalgus or cavovarus foot deformities underwent treatment using PECO. Outcomes were analyzed at 6 months and primarily included neurovascular outcomes and wound infection rates. Secondarily, radiographic and functional (visual analog scale for pain [VAS], 36-Item Short Form Medical Outcomes Survey [SF-36], and Foot Function Index [FFI] scores) outcomes were also assessed. Results: There were no reported cases of superficial wound infections, lateral calcaneal or sural nerve dysesthesia. Minor complications occurred in 6/41 feet. The mean postoperative hindfoot correction was 8.3 ± 2.2 mm (range: 6-15mm) compared to preoperative status. Compared to preoperative status, significant improvements ( P = .001 for all) were seen in the VAS, SF-36, and FFI at 6 months postoperatively. Conclusions: PECO resulted in minimal complications with no lateral calcaneal or sural nerve dysesthesias and no wound complications. It also resulted in significant improvements in postoperative radiographic and functional outcomes from baseline to 6-months postoperatively, demonstrating its use as a safe and effective means of treating hindfoot malalignment. Level of Evidence: Level IV, retrospective case series.

Background Subtalar arthrodesis is a treatment option for pain due to posttraumatic arthritis following calcaneal fractures. The goal of this study is to examine the results of arthroscopic subtalar arthrodesis for posttraumatic arthritis following calcaneal fractures. Patients and Methods: We performed a retrospective case series reviewing 37 consecutive patients (36 male) treated for posttraumatic arthritis following calcaneal fractures by arthroscopic subtalar arthrodesis. The fractures were due to high-energy injuries in 81% of cases, and 12 fractures (32.4%) had been previously treated with internal fixation. Average follow-up was 57.5 months. Results Average American Orthopedic Foot and Ankle Society (AOFAS) scores significantly improved from 49.0 ± 10.9 points preoperatively to 76.0 ± 8.0 points at final follow-up. Average time to union was 12.5 weeks. Six patients (16.2%) suffered complications: superficial wound infection (2.7%), symptomatic hardware that warranted removal (5.4%) and nonunion (8.1%) presented nonunion. All three cases had prior internal fixation through an extensile lateral approach, and fused after a repeat surgery. Conclusion Arthroscopic subtalar arthrodesis offers consistent improvement in cases of posttraumatic arthritis following calcaneal fractures, with a union rate similar to published series of open arthrodesis. We observed more nonunions in patients who had been treated previously with internal fixation. In spite of this, we continue to recommend arthroscopic subtalar arthrodesis, as it preserves the soft tissue envelope better than open techniques.

Objective: The aim of the present study was to evaluate the association between the calcaneal spur incidence and age, gender and side. Methods: Lateral ankle X-rays of 1335 patients (550 (41.2%) females and 758 (58.8) males; mean age: 46.5 ± 13.5 years) who referred to our hospital because of trauma were reviewed. Incidence of plantar calcaneal spur, posterior calcaneal spur and association of such incidences with age, gender and side were all evaluated. Results: Incidences of plantar calcaneal spur and posterior calcaneal spur were detected as 32.2% (male: 31%, female: 34%) and 13.1% (male: 11%, female: 16%), respectively. Incidence of plantar calcaneal spur increased by age whereas there was not any association with gender and location. The highest incidence was detected as 41.8% over 70 years of age. Incidence of posterior calcaneal spur increased by age and female gender whereas no significant association was observed with location. The highest incidence was detected as 22.3% between 61 and 70 years of age. Conclusion: Incidences of plantar and posterior calcaneal spur were detected as 32.2% and 13.1%, respectively. Both plantar and posterior calcaneal spur incidence increases by age. Posterior calcaneal spur occurs significantly more frequently in females while, no difference is found between the males and females in incidence of the plantar calcaneal spur. Level of evidence: Level IV, diagnostic study. Keywords: Calcaneal spur, Heel spur, Bone spur, Incidence, Foot

Objective To evaluate the results of surgical treatment of intraarticular calcaneal fractures, and also to analyse the variables that influence the final clinical and radiological outcomes as well as the complications. Material and methods We retrospectively analysed 86 intraarticular calcaneal fractures in 78 patients, who underwent surgery with an extended lateral approach and reconstruction plate. The mean age was 48 years (16–74 years) and the mean follow-up was 4.6 years (9–99 months); 54 patients (69.2%) suffered falls from less than 3 m in height or banal injuries and 24 patients (30.8%) falls from more than 3 m in height or high energy-accidents. According to the Sanders classification we operated 12 (15%) type II, 54 (62.8%) type III and 20 (23.2%) type IV fractures. Results The postoperative mean AOFAS score was 73.9 points, with good or excellent results in 57% of the patients. Twelve cases (14%) suffered surgical wound complications and 11 (12.8%) required subtalar arthrodesis. Significantly better results were obtained in the patients younger than 30 years old, patients that fell from less than 3 m in height and patients with Sanders fractures types II and III compared to type IV, which were associated with higher rate of subtalar arthrodesis. Conclusions We consider that open reduction and internal fixation of intraarticular fractures of the calcaneus with reconstruction plate is a valid treatment alternative. Given the complications described and the secondary subtalar arthrodesis rate, we recommend a meticulous technique carried out by experienced surgeons.

Background: Conventionally, the extended lateral approach (ELA) served as the standard extensile approach for intraarticular calcaneal fracture fixation. However, this approach has a high rate of wound complications. The purpose of this study was to describe an alternative approach, the posteriorlateral approach (PLA) and compare it to the ELA regarding soft tissue complications and functional outcome. Materials and Methods: 32 patients operated through PLA and 66 patients treated through ELA were included in this retrospective study. Major and minor soft tissue complications up to 3 months postoperatively were recorded. Eighteen patients of the PLA group and 32 patients of the ELA group were available for 1-year functional outcome assessment with the American Foot and Ankle Score (AOFAS) score. Results: The PLA group had no major complications requiring surgical intervention. Six patients (19%) had minor wound complications. The ELA group had 8 (12%) major complications and 9 (14%) minor complications. There were no significant differences in AOFAS scores at 1-year followup. PLA is a safe and efficient approach for open reduction and internal fixation of displaced intraarticular calcaneal fractures. Conclusion: In selected cases when fracture comminution and displacement may not be adequately treated through a less invasive approach, it is a good alternative with less concern about wound complications as in ELA.

Purpose To compare fixed- or variable-angle locking screws in calcaneal fracture plates using a sawbones biomechanical model. Methods Intra-articular calcaneal fractures were created in synthetic bones. Reduction and stabilization was performed with 3 different plates. In group A, a fixed-angle locking plate was used with screws fastened perpendicularly to the plate (3.5 LCP, DePuySynthes). In groups B and C (2.7 VA-LCP, DePuySynthes and 3.5 Aptus, Medartis, respectively), fracture fixation was performed using variable-angle locking plates. Biomechanical testing was conducted. Displacement of the subtalar articular surface, stiffness, maximum displacement, change in the angle of Gissane, and mode of failure under cyclic loading at 200 N, 600 N, and 1000 N (500 cycles each) were determined. Results No statistically significant difference of articular surface dislocation under cyclic loading was detected. The stiffness and maximum displacement did not reveal any disparity as well. The change in the angle of Gissane showed only minor displacement of the articular surface. Conclusion In our study, the resistance of variable-angle locking plates against articular surface displacement was similar to fixed-angle locking screws.

Background: Minimally invasive surgery (MIS) has a significant and evolving role in the treatment of displaced intra articular calcaneal fractures (DIACFs), but there is limited literature on this subject. The objective was hence to assess the clinicoradiological outcomes of DIACFs fixed with an innovative open-envelope MIS technique. Materials and Methods: 42 closed Sanders Type 2 and 3; DIACFs were included in this study. The Open-envelope approach was developed, which is essentially a limited open, dual incision, modified posterior longitudinal approach allowing excellent visualisation and direct fragment manipulation. The main outcome measures were American Orthopaedic Foot and Ankle Score (AOFAS) hindfoot score and preoperative and postoperative radiological angles. Results: The Bohler angle improved from a preoperative mean of 14.3° (range 0°–28°) to a postoperative mean of 32.46° (range 22°–42°). The Gissane angle improved from a preoperative mean of 135.83° to a postoperative mean of 128.33°. The postoperative improvement in Bohler and Gissane angles was highly significant (P < 0.001). The AOFAS scores at 6 months were excellent in nine patients, good in 15 patients, and fair in six patients. Three patients had residual valgus deformity of the heel. Conclusions: Open-envelope technique minimized soft tissue complications and achieved acceptable radiological reductions with good clinical outcomes.

We analyzed the risk factors for skin infection and necrosis after calcaneal fracture surgery and evaluated the effect of cryotherapy in preventing postoperative skin infections and necrosis. We studied 129 calcaneal fracture patients (148 feet) who had undergone open reduction and internal fixation from January 2008 to December 2010. Three groups included were: control (44 patients; 49 feet), preoperative cryotherapy (43 patients; 48 feet), and perioperative cryotherapy (42 patients; 51 feet). The wound infection rate, Maryland foot score, and postoperative visual analog scale (VAS) score were compared. Risk factors for infection were analyzed using multinomial logistic regression. Both cryotherapy groups had lower infection rates, higher Maryland foot scores, lower VAS scores, and shorter hospitalizations than the control group (p .05). The perioperative cryotherapy group had a lower infection rate, higher Maryland foot score, and shorter hospitalization (p .05) but similar VAS score compared with the preoperative cryotherapy group (p .05). Pre- and postoperative cryotherapy, postoperative drainage, surgical timing, smoking index, alcoholism, and suture method were risk factors for postoperative infection and necrosis. The risk of these can be largely reduced by patients not smoking and drinking alcohol and surgeons choosing the appropriate surgical timing, improving the suturing method, and performing postoperative drainage. Perioperative cryotherapy might be an effective method to decrease the postoperative infection rate, shorten the hospital stay, and reduce postoperative pain. Our findings require further validation in well-designed randomized controlled trials.

Calcaneal fractures are known to influence patients’ quality of life negatively. The type of calcaneal fracture might have a relation with the patient outcome. To inform patients in an early stage on how their calcaneal fracture may affect their lives, knowledge of the fracture characteristics is necessary. This study evaluates the association of type of calcaneal fracture, measurement of conventional radiograph angles, and the Sanders classification with patient-reported outcomes. This is a retrospective study based on a prospective trauma database including all patients aged 16 years or older with a calcaneal fracture admitted in one of the participating trauma level I or II hospitals. Patients, trauma, and fracture characteristics were collected. The conventional radiographs were evaluated in which type of fracture, and Bohler’s, Gissane’s, and calcaneal compression angles were determined. Also, the CT images were classified according to Sanders. In addition, displaced intra-articular calcaneal fractures were separately analyzed. A questionnaire was sent to the included patients that consisted of the EQ-6D, patient-specific characteristics, satisfaction with foot appearance and wearable shoe range, complications, and capability to work. A total of 396 patients with 442 calcaneal fractures were eligible for follow-up. Two hundred fifteen patients with 246 calcaneal fractures participated. Patients with a calcaneal fracture into the talar surface reported a worse quality of life (p = 0.010), were less satisfied with their feet (p

Malunion of calcaneal fractures is a common complication after improper nonoperative treatment. It may develop into posttraumatic subtalar osteoarthritis, lateral calcaneal wall prominence, and severe foot deformities. This Technical Note reports the technical aspects of lateral endoscopic calcaneoplasty with posterior arthroscopic subtalar arthrodesis for the treatment of malunited calcaneal fracture with lateral calcaneal wall prominence and posttraumatic subtalar osteoarthritis. This technique was chosen because it can reduce the risk of wound complication compared with a conventional lateral extensile approach. This Technical Note describes the use of the technique in a patient with prone position. This offers the advantages of easier access to the lateral surface of the calcaneus and posterior facet of the subtalar joint, and is less invasive to the soft tissue envelope on the lateral side of the foot. Moreover, the concomitant bone void area of the subtalar joint can be dealt with by an arthroscopic procedure.

Cavovarus deformity is a complicated condition most commonly resulting from neurologic, posttraumatic, or iatrogenic pathologic conditions. Careful evaluation of the cavovarus patient is necessary in determining appropriate treatment course. Weight-bearing radiographs are necessary, and advances in computed tomographic technology can be beneficial in identifying level of involvement. In the case of operative treatment of inframalleolar deformity, assessment of the subtalar joint position and relation of calcaneocuboid joint can be of assistance. Multiple osteotomies have been described providing uniplanar, biplanar, and triplanar correction and in the appropriate setting can prove beneficial to the surgeon in treating hind-foot cavovarus deformity.

Background Degloving of the sole of the foot is a rare and serious injury because the heel pad cannot be replaced by similar tissue. The management is challenging and only a few cases have been reported with different treatment regimens. Methods Here, we report on a 46-year-old female patient with complex foot trauma consisting of complete avulsion of the heel pad at the hindfoot and a soft tissue defect at the posterior aspect of the heel accompanied by rupture of the anterior tibial tendon and fractures of the talus, calcaneus and midfoot. The sole of the foot was fixed to the calcaneus with multiple temporary Kirschner wires and moist wound dressings. The anterior tibial tendon was sutured. The soft tissue defect at the posterior heel was treated with a free anterolateral thigh flap. The fractures were fixed in staged procedures. Results At 2-year follow-up, the patient had a durable soft tissue cover over the heel with full sensation over the sole and a pliable flap over the posterior aspect of the heel. The patient was able to fully bear weight and was pain free during her daily activities in comfortable, custom shoes. All fractures had healed, the talar neck fracture after one revision and bone grafting. The foot was plantigrade and stable with preserved painless but limited range of motion at the ankle, subtalar and mid-tarsal joints. Conclusion The unique tissue at the sole of the foot can be salvaged even in cases of full degloving at the hindfoot with the simple method of anchorage with multiple temporary K-wires. Traumatic defects of the vulnerable skin at the posterior aspect of the heel requires durable coverage with free flap coverage. With staged treatment of all bone and soft tissue injuries, a favorable result can be obtained even in case of a complex foot trauma.

Background: Calcaneal malunion is a common complication of nonoperative management of calcaneal fracture, which leads to a disruption of the biomechanics of the lower extremity, pain, and permanent disability. Our aim was to evaluate pain, function, and gait after combined subtalar joint fusion, calcaneal osteotomy, and lateral wall exostectomy for patients with neglected calcaneal fractures with malunion. Methods: Eighteen patients with malunited calcaneal fractures, varus deformity, and subtalar arthritis were operated upon and then followed up for 18 months. All cases were assessed clinically using the American Orthopaedic Foot & Ankle Society (AOFAS) and visual analog scale (VAS); radiologically by measuring the talar inclination, talocalcaneal and talus-first metatarsal angles, and talocalcaneal height; and biomechanically by measuring the stride duration, step width, comfortable speed, and ground reaction forces in relation to the body weight. Results: A significant improvement in AOFAS (59.8 preoperatively to 80.2 after 18 months) and VAS (61.1 preoperatively to 29.4) was found. Also, our study revealed a significant improvement in the radiographic measurements including the valgus angle, the talocalcaneal angle, the talocalcaneal height, and the talar inclination angle. The gait analysis found that the maximum loading force in the push-off phase and comfortable speed yielded a significant improvement postoperatively. However, no significant differences between the preoperative data and the final follow-up in terms of the step width, stride duration, maximum peak force during loading phase, and minimum peak force during midstance phase were found. Conclusion: The combination of valgus calcaneal osteotomy, lateral wall exostectomy, and subtalar fusion resulted in pain reduction, improved function, and better gait. However, the limited bone stock for the graft used in the subtalar fusion made use of this technique in severely reduced height unadvisable. Level of Evidence: Level IV, case series.

Background: A thorough understanding of the clinical and radiographic anatomy of the calcaneus and its articulations is crucial when attempting less invasive procedures for intraarticular calcaneus fractures. Objective: The aim of this work is to evaluate the functional outcome and to assess the anatomical restoration of the calcaneus with radiographic measurements after percutaneous fixation of Sanders type II and type III calcaneal fractures by K-wires and cannulated screws. Patients and methods: This was a prospective study that is conducted on 23 patients whom were classified as Sanders type II, III Calcaneal fractures. This study was done at Alexandria Police Hospital and Zagazig University Hospital. These patients were followed up for at least 6 months postoperatively. All patients in the study were evaluated including history taking and clinical examination. All patients had preoperative lab investigations and were evaluated radiologically with X-ray calcaneus and CT scan, and were followed up at outpatient clinic twice in the first week then once a week for the next two months. Results: The final results at the end of this study were satisfactory in 91.3% of patients and unsatisfactory in 8.7% of patients. About (81.3%) of the excellent results were obtained in Sanders type II fractures, while 18.7 % of the excellent results were obtained in Sanders type III fractures. Conclusion: Less invasive surgical techniques for treating displaced intraarticular calcaneus fractures have been undertaken in an attempt to reduce complications and improve recovery when surgery is indicated. These emerging techniques may be beneficial in patients with soft-tissue compromise, multiple comorbidities, and displaced intraarticular fractures with minimal comminution.

The choice of treatment for Sanders Type II and Type III calcaneal fractures remains controversial with unclear patient functional outcomes. A meta-analysis was done to compare the functional outcome of ORIF vs primary subtalar arthrodesis (PSA) according to American Orthopedic Foot and Ankle Score (AOFAS) hindfoot-ankle scores. The PubMed, Embase, and Cochrane Library Databases were searched by two independent evaluators. Fourteen studies met the eligible criteria. ORIF of 501 Type II and Type III fractures was compared to primary subtalar arthrodesis treatment of 57 Type II and Type III fractures. AOFAS for a mixed ORIF group of “Type II and III” fractures was 82.16 ± 1.58 at average follow-up of 25.3 months. For a mixed PSA group of “Type II and III” fractures, the AOFAS was 74.22 ± 2.45 at average follow-up of 28.0 months. This showed a difference between ORIF and primary subtalar arthrodesis of 7.94 points (95% confidence interval [CI] = 7.75–7.98; p value .004) favoring ORIF when adjusting for minimally invasive and percutaneous methods. Without adjustment, there was a difference of 6.54 points favoring ORIF (95% CI = 6.22–6.46; p value .017). In conclusion, while high-quality randomized controlled trials comparing ORIF to primary subtalar arthrodesis for Type II and Type III fractures would further elucidate superior treatment outcomes, this meta-analysis of available data shows a tendency for ORIF of Type II and Type III Sanders calcaneal fractures to have a better functional outcome at approximately 2 years postoperatively compared to primary subtalar arthrodesis.

Acute Achilles tendon rupture is one of the most common tendon injuries. This prospective study aimed to evaluate the functional outcomes of augmented repair of acute Achilles tendon rupture with peroneus brevis tendon transfer and fixation to an oblique calcaneal transosseous tunnel. Functional evaluation was performed using the American Orthopaedic Foot & Ankle Society (AOFAS) score and Achilles Tendon Total Rupture Score (ATRS). Postoperative complications were recorded. This study included 33 males and 9 females, with a mean age of 26.1 ± 4.2 years. The Achilles tendon ruptures were right in 24 patients and left in 18 patients. The cause of rupture was sports injuries in all patients. The mean distance from the calcaneal insertion to the tear site was 4.4 ± 1.3 cm. The mean time from injury to surgery was 2.4 ± 1.6 days. The mean follow-up time was 40.3 ± 4.9 months. The mean AOFAS and ATRS scores were 99.3 ± 1.2 and 95.9 ± 1.9, respectively, at 12 months of follow-up. The mean time to return to work was 12.1 ± 1.2 weeks. The mean time to return to light sports activities was 16.1 ± 1.8 weeks postoperatively. None of the patients developed re-rupture. Augmented repair of acute Achilles tendon ruptures with peroneus brevis tendon transfer is a robust repair with excellent functional outcomes and early weight-bearing and return to sports activities.

Background: Posttraumatic osteoarthritis (PTOA) of the subtalar joint is a serious, disabling, and frequent complication following intra-articular calcaneal fractures (IACFs). Using plain radiographs to assess the subtalar joint for PTOA is imprecise and insensitive, hindering progress toward improving treatment and assessing outcomes. This study explored how low-dose weightbearing computed tomography (WBCT) can be used to provide reliable, quantitative 3D measures of subtalar joint space width (JSW) following IACF and correlated the 3D JSW with clinical outcomes. Methods: After institutional review board approval, 21 patients (15 male; age, 28-70 years) who sustained IACFs and were treated with percutaneous surgical reduction underwent WBCT scans at follow-up visits 2 to 15 years (average, 7.8 years) after surgical treatment. Subtalar joint 3D JSW was computed after a semiautomated protocol was used to segment the talus and calcaneus from the WBCT data. Mean and minimum 3D JSW measurements were calculated and compared with Kellgren-Lawrence (KL) radiographic osteoarthritis grade, RAND-36 Physical (PCS) and Mental (MCS) Component Scores, and visual analog scale (VAS) pain scores. Spearman’s rank correlation was used to detect the strength of association between variables, with significance set at P < .05. Results: Mean 3D JSW values measured from WBCT for patients with IACFs ranged from 0.9 to 2.5 mm (1.7 ± 0.4 mm) over the entire subtalar joint. Intra- and interrater reliabilities for the WBCT-based JSW measurement technique were 0.95 (95% CI, 0.91-0.97) and 0.97 (95% CI, 0.95-0.98), respectively. Mean and minimum 3D JSW values correlated inversely with VAS pain scores and KL grade ( P < .05), particularly in central and posterior subtalar regions. Conclusion: WBCT-based methods were used to quantify the preservation/loss of JSW in patients with IACFs, enabling more accurate, definitive measurement of subtalar PTOA. The results of this study demonstrate that WBCT can be utilized to objectively assess subtalar PTOA and help us to better understand how arthritic changes affect actual patient experience. Level of Evidence: Level III, prognostic comparative study.

An 18-year old male patient, with a history of paragliding accident, sustaining a coronal shear fracture of the body of the talus, an anterior process fracture of the calcaneus extending to the calcaneocuboid joint and a nondisplaced navicular body fracture at the right foot and a displaced fracture of the navicular body accompanied with posteromedial process fracture of the talus at the left side was referred to our emergency clinic. For the right foot, the coronal plane fracture of the talar body was anatomically reduced and fixed with screws. For the left foot, screw fixation was performed through the lateral aspect to fix the large posteromedial fragment. Small bone fragments were removed from the left navicular fracture, and the main fragments were also fixed with screw. The talo-navicular joint was stabilised with a Kirschner wire. At 36 months follow-up, bilateral foot and ankle functions were satisfactory, Maryland scores of the right and left foot were 85 (good) and 90 (excellent), respectively, and the patient regained his full activity level by the 5th month postoperatively. With reference to the number and types of fractures in this one patient, we present a standard protocol for treatment of isolated talus, navicular and calcaneal fractures presenting together in a single foot injury.

The optimal treatment of the calcaneal fracture is a controversial topic. Many patients get a very good result with open reduction and internal fixation using extensile lateral approach. But there are many patients who do not qualify this category. This is the reason why many of them are either denied any surgical intervention or are put at a significant risk of developing major complications because of the open surgical intervention. The height, width, length and shape of the hind foot can be restored using Minimally invasive reduction and fixation (MIRF) and also the orientation of the posterior facet of calcaneus (Bohler’s angle) can be restored. In this paper we present a series of 23 patients treated with minimally invasive reduction and fixation using Steinmann as a treatment method for the patients not suitable for open reduction and internal fixation. The use of Steinmann pin in the MIRF technique proved out to be very effective. As per our experience the time of the surgery is short and it can be easily performed even in the presence of extensive soft tissue swelling in the period immediate after the injury. The risk of infection is low also the morphology of the calcaneus was improved and properly maintained in the term of Bohler’s angle. This technique is very suitable for the patients with medical co-morbidities such as smokers, diabetics and is also very effective for the patients who are not suitable foe extensile approach and internal fixation.

We examined the added value of 3-dimensional (3D) prints in improving the interobserver reliability of the Sanders classification of displaced intraarticular calcaneal fractures. Twenty-four observers (radiologists, trainees, and foot surgeons) were asked to rate 2-dimensional (2D) computed tomography images and 3D prints of a series of 11 fractures, selected from cases treatment at our level I trauma center between 2014 and 2016. The interobserver reliability for the Sanders classification was assessed using kappa coefficients. Three versions of the Sanders classification were considered: Sanders classification with subclasses, Sanders classification without subclasses, and the combination of Sanders types III and IV because of the high incidence of comminution in both types. The reference standard for classification was the perioperative findings by a single surgeon. The 3D print always yielded higher values for agreement and chance-corrected agreement. The Brennan-Prediger-weighted kappa equaled 0.35 for the 2D views and 0.63 for the 3D prints for the Sanders classification with subclasses (p = .004), 0.55 (2D) and 0.76 (3D) for the classification without subclasses (p = .003), and 0.58 (2D) and 0.78 (3D) for the fusion of Sanders types III and IV (p = .027). Greater agreement was also found between the perioperative evaluation and the 3D prints (88% versus 65% for the 2D views; p

Background: Calcaneal tuberosity avulsion fractures are challenging to treat because of the poor bone stock and high risk of fixation failure secondary to the strong Achilles tendon pull. The purpose of this study is to compare the tensile force to failure of 2 different types of screw fixation construct in a cadaveric model of calcaneal tuberosity avulsion fracture. Methods: An oblique osteotomy was created in the calcanei of 7 matched pairs of cadaveric specimens to simulate a tuberosity avulsion fracture and one specimen from each pair randomized into one of the 2 groups for comparison. Two cancellous screws were inserted perpendicular to the fracture line at the posteromedial and posterolateral corners of the avulsed fragment for the 2-screw construct. For the second group, an additional stab incision was made at the midline of the Achilles insertional region for a screw placed between the initial 2 screws with a trajectory toward the calcaneocuboid joint in the 3-screw construct. These specimens were then mounted and loaded to failure. Results: The mean force to a predefined failure at 3.0-mm gap for the 3-screw construct was 468.7 ± 267.9 N vs 278.9 ± 164.0 N for the 2-screw construct ( P < .001). The addition of a central nonparallel screw in the 3-screw construct significantly increased the force required for fracture gap displacement at all cut-off points (1.0-8.0 mm) when compared to the 2-screw construct ( P < .001). Notably, the mean peak tensile force for the 3-screw construct was 499.4 ± 255.4 N occurred at the gap displacement of 4.1 mm for the 3-screw construct whereas the mean peak tensile force for the 2-screw construct was 315.9 ± 162.4 N displacing the gap at 4.3 mm. Conclusion: This study showed that an additional central nonparallel screw in the 3-screw construct provided significant mechanical superiority compared to a 2-screw construct. Clinical Relevance: The present study supported the use of augmented fixation with an additional central off-axis screw to reduce risk of fixation failure in calcaneal tuberosity avulsion fractures.

Background Trans-calcaneal suture technique is an economical and effective method for repairing Achilles tendon sleeve avulsion. Whether cancellous bone fixation upon this technique could accelerate tendon-to-bone healing is unknown. The purpose of this study is to compare the effect of cortical versus cancellous bone fixation on tendon–bone healing with a novel rat trans-calcaneal suture model. Methods Trans-calcaneal suture treatment was carried out on the right hindlimb in male Sprague–Dawley rats (N = 80). They were randomly divided into the cortical group (Achilles fixed to the calcaneal cortical bone, n = 40) and the cancellous group (Achilles fixed to the calcaneal cancellous bone, n = 40). Gait analysis and immunohistochemistry were performed 1, 4, 7, and 14 days after the operation. Gross observation, biomechanical analysis, micro-CT, and histological analysis were performed 4 and 8 weeks after surgery. Independent-samples t tests were used for comparison between groups. Results At 1, 4, and 7 days, the swing time of the affected limb in the cancellous group decreased, while the duty cycle, the maximum contact area, the print area, and the mean intensity increased significantly. The cross-sectional area of the tendon–bone junction in the cancellous group was smaller, and the failure load and stiffness were higher 4 weeks after the operation. The cancellous group showed more proportion of new bone and a relatively well-organized and dense connective tissue interface with better fibrocartilage-like tissue at 4 weeks after the operation. The ratio of ED2 + macrophages in the cancellous group was significantly higher than in the cortical group on 1, 4, 7, and 14 days. There were no significant differences in gait at 2 weeks, in appearance, biomechanics, new bone formation, and histology at 8 weeks after surgery between the two groups. Conclusion In the new rat trans-calcaneal suture model, cancellous fixation can accelerate tendon-to-bone healing in the early stage, which perhaps is related to the abundant bone marrow tissue in the cancellous bone that modulates the inflammatory processes.

Percutaneous reduction and cannulated screw fixation (PR + CSF) for treatment of calcaneal fractures in pediatric patients has been proven to achieve satisfactory outcomes with few complications. But it is also a difficult technology due to the limited exposure and surgeons are unable to reduce articular surface under direct vision. The purpose of this study was to analyze the outcomes of applying 3D printing technology to preoperative preparation and Intraoperative operating for the treatment of calcaneal fractures in children.Pediatric patients with calcaneal fractures from January 2010 to December 2018 were reviewed during study period. Preoperative radiographs and computed tomography scans were collected to classify the fractures, reconstruct 3D printed model and evaluate postoperative outcomes. The blood loss, operative time, number of fluoroscopies, surgeon and patient satisfaction were used to assess the effectiveness, feasibility and safety of 3D printing technology. Functional results were measured by American Orthopedic Foot and Ankle Society (AOFAS) hindfoot score.12 patients (10 boys and 2 girls) with 17 fractures were involved in our study. There were significant differences in the average Böhler angle before operation compared with that after operation and at last follow-up (P 0.001). Similarly, the calcaneal height and length postoperatively and at the end of follow-up time were proved to have significant difference (P 0.05) compared to preoperative. CT scan showed good reduction of the posterior facet according to Goldzak index. The average subjective AOFAS hindfoot score was 94.1. Both patients and surgeon made sense of the 3D printed model that can help them getting more information about the factures and making preoperative plans. No wound complication was found in this study.This study indicated that percutaneous reduction and cannulated screw fixation (PR + CSF) assisted by 3D printing technology in the treatment of calcaneal fractures in pediatric patients achieve good outcomes, with specific preoperative preparation, satisfactory functional recovery and fewer complications.III.

The best treatment for displaced, intraarticular fractures of the calcaneum remains controversial. Surgical treatment of these injuries is challenging and have a considerable learning curve. Studies comparing operative with nonoperative treatment including randomized trials and meta-analyses are fraught with a considerable number of confounders including highly variable fracture patterns, soft-tissue conditions, patient characteristics, surgeon experience, limited sensitivity of outcome measures, and rehabilitation protocols. It has become apparent that there is no single treatment that is suitable for all calcaneal fractures. Treatment should be tailored to the individual fracture pathoanatomy, accompanying soft-tissue damage, associated injuries, functional demand, and comorbidities of the patient. If operative treatment is chosen, reconstruction of the overall shape of the calcaneum and joint surfaces are of utmost importance to obtain a good functional result. Despite meticulous reconstruction, primary cartilage damage due to the impact at the time of injury may lead to posttraumatic subtalar arthritis. Even if subtalar fusion becomes necessary, patients benefit from primary anatomical reconstruction of the hindfoot geometry because in situ fusion is easier to perform and associated with better results than corrective fusion for hindfoot deformities in malunited calcaneal fractures. To minimize wound healing problems and stiffness due to scar formation after open reduction and internal fixation (ORIF) through extensile approaches several percutaneous and less invasive procedures through a direct approach over the sinus tarsi have successfully lowered the rates of infections and wound complications while ensuring exact anatomic reduction. There is evidence from multiple studies that malunited displaced calcaneal fractures result in painful arthritis and disabling, three-dimensional foot deformities for the affected patients. The poorest treatment results are reported after open surgical treatment that failed to achieve anatomic reconstruction of the calcaneum and its joints, thus combining the disadvantages of operative and nonoperative treatment. The crucial question, therefore, is not only whether to operate or not but also when and how to operate on calcaneal fractures if surgery is decided.

Category: Hindfoot; Trauma Introduction/Purpose: The fixation of displaced intraarticular fractures of the calcaneus have posed many challenges for the surgeon, including an anatomic reduction, fracture stabilization, and soft tissue concerns. The extensible lateral and sinus tarsi approaches must be delayed until soft tissues concerns resolve and despite this are susceptible to wound necrosis and skin infections. Intramedullary fixation allows immediate fixation without soft tissue compromise. Methods: The retrospective case series is comprised of 23 patients; 19 intramedullary fixation of the calcaneus and 4 primary arthrodesis with the FH Orthopedics CalcaNail. Fracture classification, timing to surgery, accuracy of reduction, complications, and outcome were recorded. Results: There were zero wound complications. Bohler’s angle was restored as well as articular surface. One patient required implant removal after healing seconding to prominent hardware. One patient required conversion to a subtalar arthrodesis. There were no implant mechanical failures. Conclusion: The intramedullary fixation of calcaneus fractures has been performed extensively outside the US with documented success. This series of early US experience exhibits similar utility. The ability to reduce the fracture intrafocally and stabilize with a minimally invasive approach have proven useful with no incidence of wound complications. Not to mention no delay from time of injury to surgery is needed.

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.

The aim of the current study is to evaluate the functional and radiological outcomes of Malerba osteotomy in comparison to the standardized combined Evans/Medial Displacement Calcaneal Osteotomy (MDCO) in the management of symptomatic flexible pes planus in young adults. Prospective randomized control trial included 34 feet (33 patients), 17 cases in each group. Functionally, patients were assessed by AOFAS and FADI scores. Radiographic evaluation included calcaneal pitch, lateral talo-1st metatarsal, AP talo-first metatarsal, AP talo-calcaneal angles, and the talar coverage percentage. Pre-operative and three years follow-up scores and angles were compared between both groups. No statistically significant difference could be detected between both groups (P value 0.87). However, the data showed statistically significant difference in each group when comparing (pre-operative and third year follow-up scores and angles) (P value

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. 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, Bohler’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. 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 Bohler’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). 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.

Background Percutaneous reduction, cannulated screw fixation and calcium sulfate cement grafting (PR + CSC) for treatment of displaced and intra-articular calcaneal fractures (DIACFs) is a difficult technique, because the minimally invasive treatment has limited exposure and cannot be used to reduce articular surface under direct vision. The goal of this study was to apply 3D printing technology to preoperative planning and surgery of DIACFs, and to evaluate its effectiveness, feasibility and safety in fracture repair. Methods We enrolled 81 patients with DIACFs in the study from August 2015 to August 2017. Patients with DIACFs in our hospital were randomly divided into the 3D printing group (40 cases) and the conventional group (41 cases). The operation duration, blood loss volume and the number of fluoroscopy were compared. Radiological results were evaluated using radiographs and functional results were evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) score. The complications were also assessed. In addition, we made a questionnaire to verify the usefulness of the 3D printed model for both doctors and patients. Results The operation duration, blood loss volume and the number of fluoroscopy in 3D printing group were significantly less than that in the conventional group. Besides, 3D printing group achieved significantly better radiological results than conventional group both postoperatively and at the final follow-up except the calcaneal width at the final follow-up. The AOFAS score in the 3D printing group was significantly higher than that in the conventional group. In addition, the questionnaire from doctors and patients exhibited high scores of overall satisfaction of the 3D printed models. As for complications, there was no significant difference among the two groups. Conclusion This study suggested the clinical feasibility of PR + CSC assisted by 3D printing technology in the treatment of DIACFs. Level of evidence II.

Background: Severely displaced calcaneal fractures can result in considerable morphology derangement and may be accompanied by soft tissue compromise. Delayed operative restoration of the calcaneal morphology may result in acute retensioning of the damaged soft tissue with associated wound-related complications. In this study, we describe a staged treatment of displaced intra-articular calcaneal fractures that uses temporary transarticular Kirschner wire (K-wire) fixation and staged conversion to definite fixation. Methods: We identified all of the patients who were treated at our institution for calcaneal fractures between 2015 and 2019. A total of 17 patients with 20 calcaneal fractures were selectively treated with 2-stage management. Temporary transarticular K-wire fixation was performed 24 hours after the injury to restore calcaneal morphology and the surrounding soft tissue. After the soft tissue was considered safe, delayed open reduction and internal fixation was performed. The time to definite surgery, radiographic alignment, wound complications, time to radiographic union, and hindfoot American Orthopaedic Foot & Ankle Society (AOFAS) scores were recorded. Results: The average follow-up period was 17 months (range, 12-43). The average Böhler angle increased from a mean of −22 degrees (range, −109 to 25) to 25 degrees (range, 0 to 47) after temporary transarticular K-wire fixation. The mean time from temporary pinning to conversion to definite internal fixation was 20 (range, 10-32) days. There were no immediate postoperative complications. The average time to radiographic union was 13.7 (range, 10-16) weeks. The mean AOFAS score was 87 (range, 55-100). No infections or wound complications were reported during the follow-up period. Conclusion: Temporary transarticular pinning for staged calcaneal fracture treatment is safe and effective in restoring the calcaneal morphology. This novel and relatively simple method may facilitate delayed operation and decrease wound-related complications. Level of Evidence: Level IV, retrospective case series.

The purpose of this study was to demonstrate whether application of the so-called safe incision when performing calcaneal sliding osteotomies reduces the risk of sural nerve injury. Patients who underwent either medial or lateral sliding calcaneal osteotomies between 2010 and 2018 were analysed retrospectively. A thorough neurological examination was performed, and the location of the surgical wound and the type of wound closure were recorded. The European Foot and Ankle Surgery (EFAS) score and 12-item Short Form Survey (SF-12) were also documented. A total of 57 patients were included, of which 20 (35.1%) had a sural nerve injury. Five patients had a neurapraxia (8.8%), while 15 patients had a permanent injury (26.3%). Respecting the “safe incision” decreased sural nerve injury (p = 0.02). The type of osteotomy and closure was not significant. No significant differences were found in the functional tests between the different techniques, or between patients who presented sural nerve injury and those who did not. Sural nerve injury after calcaneal sliding osteotomies is higher than previously reported in the scientific literature, with an incidence of 35.1% (20/57 patients). Respecting the so-called safe zone (oblique incision that runs through the point that is > 1/3 of the distance from the tip of the lateral malleolus to the posteroinferior margin of the calcaneus) clearly decreases the incidence of sural nerve injury. Finally, the majority of patients remained asymptomatic despite the neurological injury.

Background: Open reduction and internal fixation (ORIF) of displaced intra-articular calcaneal fracture (DIACF) by extensile lateral approach is widely used but is technically challenging. In this study, the learning curve for ORIF of DIACF by extensile lateral approach was investigated. Methods: Between March 2014 and July 2018, 45 cases consisting of 40 patients underwent operative treatment for DIACF by the extensile lateral approach performed in all instances by a single surgeon. A moving average and cumulative summation control chart (CUSUM) were used for learning curve analyses. Operative failure was defined when at least 1 of the following parameters were unsatisfactory: reduction of Gissane angle and Böhler angle, posterior facet congruency, calcaneal width, subfibular impingement, axial alignment, or calcaneocuboid joint congruency. Results: The mean operating time was 117.4 minutes. Regarding the quality of reduction, the mean preoperative sum of the 7 parameters was 5.1 and improved to 0.6 postoperatively. The CUSUM for operative success peaked in the 20th case. The CUSUM and moving average graphics of operating time peaked at the 9th case and registered nadirs at the 34th case, with slight ascent and decent. The operating time for 20 cases in phase 1 (1-20) and for 25 cases in phase 2 (21-45) of the learning curve did not differ significantly. There was no statistical difference in the severity of fracture pattern. By comparison, in phase 2, patients showed a significantly better postoperative reduction quality. Conclusion: As indicated by multidimensional statistical analyses, primary technical competence in improving the reduction quality of DIACF was achieved after the initial learning period with 20 cases. After the learning curve for ORIF of DIACF, a better reduction quality in the sum of reduction parameters was observed. Level of Evidence: Level III, comparative series.

This study aimed to compare the efficacy and safety among Kirschner wire, anatomical plate fixation and cannulated screw treatments in patients with open calcaneal fractures, and to explore the predictive factors for treatment response and complication occurrence. The 142 open calcaneal fracture patients were enrolled in this study, who received fixation procedures of Kirschner wire, anatomical plate fixation or cannulated screw on demand. Treatment efficacy was assessed by AOFAS score and occurrence of complications was recorded. No difference of AOFAS score was observed among Kirschner wire, anatomical plate fixation and cannulated screw groups (P = .792), and the numbers of patients with excellent, good, medium, and poor AOFAS score in Kirschner wire group were 16 (16.2%), 42 (42.4%), 32 (32.3%), and 9 (9.1%), which in anatomical plate fixation group were 4 (16.7%), 11 (45.8%), 7 (29.2%), and (8.3%), and in cannulated screw group were 1 (5.3%), 10 (52.6%), 6 (31.6%), and 2 (10.5%), respectively. No difference of total complication occurrence (P = .709) or specific complications including skin graft (P = .419), flap graft (P = .229), deep infection (P = .644) or amputation (P = .428) was discovered among 3 groups. Logistic regression analysis revealed that fixation options did not affect treatment response and complication occurrence (all P > .05), while higher Gustilo type correlates with decreased treatment response (P

Category: Arthroscopy, Trauma Introduction/Purpose: Surgical treatment of calcaneal fractures using the extensile lateral approach is associated with high rates of infection and soft tissue complications. During the last years there was a trend towards less invasive fixation methods. Percutaneous and arthroscopically assisted calcaneal osteosynthesis (PACO) combines the advantages of good visualization of the posterior facet of the subtalar joint with a minimally invasive approach. We have performed this technique since 2014 in selected Sanders II and III fractures. Methods: We conducted a clinical and radiographic follow-up of 19 patients with 20 calcaneal fractures which had been treated by PACO with a minimum follow-up of 12 months. The follow-up rate was 66% (19 of 29 patients). 18 men and 1 woman with a median age of 44 years (range, 21-65) and a follow-up period of 18 months (12-33) were examined. There were 11 Sanders II and 9 Sanders III fractures. Radiographs of all feet were obtained at final follow-up to evaluate the reduction of the fractures as well as the presence of osteoarthritis of the subtalar joint. Our primary outcome was the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot score. Secondary outcomes were the Calcaneus Fracture Scoring System (CFSS), the Manchester- Oxford Foot Questionaire (MOxFQ), the Visual Analog Scale (VAS) for pain and the incidence of complications. Results: The patients were operated on after a median of 4 days after injury (range, 1-12). The operation time was 139.5 minutes (98-234). The patients were discharged 3 days (1-6) postoperatively. Postoperative radiographs showed a Böhler angle of 29.5 degrees (0-40). However, the follow-up radiographs showed subsidence of the fractures and a Böhler angle of 21 degrees (-16-36). 95% of the operated feet showed signs of posttraumatic subtalar osteoarthritis. There were no wound healing complications. Two patients were reoperated with screw removal due to prominent screws. The AOFAS score was 85 (50-100), the CFSS score 85 (26-100), the MOxFQ score 26.6 (0-73.4). The VAS pain score was 0 (0-5.7) at rest and 4 (0-8.2) during activity. Conclusion: Only a few articles have reported the outcome after percutaneous artroscopically assisted calcaneal osteosynthesis. Our results suggest that PACO gives good clinical results and a reduced risk of complications in selected calcaneal fractures. However, since this technique is technically challenging and has a steep learning curve, we expect to be able to further improve our results over time. Prospective longterm studies will be necessary to better document the potential advantages and limitations of this operating technique.

Background: To date, there is no consensus regarding which postoperative imaging technique should be used after open reduction and internal fixation of an intra-articular calcaneal fracture. The aim of this study was to clarify whether Brodén’s view is sufficient as postoperative radiologic examination to assess step-offs and gaps of the posterior facet. Methods: Six observers estimated the size of step-offs and gaps on Brodén’s view in 42 surgically treated intra-articular calcaneal fractures. These findings were compared to postoperative CT scans (gold standard). Inter- and intraobserver reliability were calculated and compared using intraclass correlation coefficients (ICCs). Results: An accuracy of approximately 75% for both step-offs and gaps was found in foot and ankle experts. Less experienced observers correctly identified step-offs and gaps in approximately 62% of cases on fluoroscopy and in 48% on radiographs. Interobserver reliability for intraoperative fluoroscopy as well as postoperative radiographs was fair for step-offs, whereas interobserver reliability for gaps was excellent. Intraobserver reliability showed a low level of agreement for intraoperative fluoroscopy, in contrast to postoperative radiographs with excellent agreement for step-offs and good agreement for gaps. Conclusion: Our results show that especially for more experienced foot and ankle surgeons, in the majority of fractures, Brodén’s view accurately showed step-offs and gaps following open reduction and internal fixation. Interobserver reliability showed a fair level of agreement for step-offs and excellent agreement for gaps. Intraobserver reliability was only enough for radiographs, not for fluoroscopy. Level of Evidence: Level IV, case series.

Background: This study was conducted to evaluate the usefulness of subtalar arthroscopy in the operative treatment of Sanders type 2 calcaneus fractures using a sinus tarsi approach. Methods: Forty-six Sanders type 2 calcaneal fractures were consecutively treated using a sinus tarsi approach. Intraoperative fluoroscopy was used to evaluate fracture reduction in the first 23 patients (fluoroscopy group), and intraoperative fluoroscopy and subtalar arthroscopy were used in the latter 23 patients (arthroscopy group). Clinical evaluations were performed using a visual analog scale, the Ankle-Hindfoot Scale developed by the American Orthopaedic Foot & Ankle Society, and Short Form Health Survey. Radiographic evaluations were performed using calcaneal and lateral radiographs and computed tomography (CT) scans. Böhler’s angles and calcaneal widths were compared between the groups. Reduction of the posterior facet was graded according to articular step, defect, and angulation of the posterior facet on CT. Results: At the last follow-up, clinical results as well as Böhler’s angles and calcaneal widths were not different between the groups. On immediately postoperative CT, reduction of the posterior facet showed a higher-than-good grade in 17 feet (73.9%) in the fluoroscopy group and a higher-than-good grade in 22 feet (95.7%) in the arthroscopy group, and these values were significantly different between the groups ( P = .04). Conclusion: A combined approach using fluoroscopy and subtalar arthroscopy showed better reduction of the posterior facet on CT than using fluoroscopy alone. Therefore, subtalar arthroscopy could be a useful method for detecting joint incongruence when using the sinus tarsi approach for Sanders type 2 calcaneal fractures. Level of Evidence: Level III, comparative series.