Neural interfacing architecture enables enhanced motor control and residual limb functionality postamputation.

Despite advancements in prosthetic technologies, patients with amputation today suffer great diminution in mobility and quality of life. We have developed a modified below-knee amputation (BKA) procedure that incorporates agonist-antagonist myoneural interfaces (AMIs), which surgically preserve and couple agonist-antagonist muscle pairs for the subtalar and ankle joints. AMIs are designed to restore physiological neuromuscular dynamics, enable bidirectional neural signaling, and offer greater neuroprosthetic controllability compared to traditional amputation techniques. In this prospective, nonrandomized, unmasked study design, 15 subjects with AMI below-knee amputation (AB) were matched with 7 subjects who underwent a traditional below-knee amputation (TB). AB subjects demonstrated significantly greater control of their residual limb musculature, production of more differentiable efferent control signals, and greater precision of movement compared to TB subjects (P < 0.008). This may be due to the presence of greater proprioceptive inputs facilitated by the significantly higher fascicle strains resulting from coordinated muscle excursion in AB subjects (P < 0.05). AB subjects reported significantly greater phantom range of motion postamputation (AB: 12.47 ± 2.41, TB: 10.14 ± 1.45 degrees) when compared to TB subjects (P < 0.05). Furthermore, AB subjects also reported less pain (12.25 ± 5.37) than TB subjects (17.29 ± 10.22) and a significant reduction when compared to their preoperative baseline (P < 0.05). Compared with traditional amputation, the construction of AMIs during amputation confers the benefits of enhanced physiological neuromuscular dynamics, proprioception, and phantom limb perception. Subjects' activation of the AMIs produces more differentiable electromyography (EMG) for myoelectric prosthesis control and demonstrates more positive clinical outcomes.

Minimally invasive technique for acute fixation and subtalar fusion of displaced intra-articular calcaneus fractures.

Displaced intra-articular calcaneus fractures (DIACFs) are difficult injuries to treat and are often encountered by orthopedic surgeons. For DIACFs treated nonoperatively or with open reduction internal fixation (ORIF), a common complication is painful subtalar arthritis and the need for a secondary subtalar fusion, which prolongs the overall recovery time. One treatment option to address this sequela involves ORIF with subtalar fusion as the primary treatment. We describe a reproducible, minimally invasive surgical technique for primary ORIF with subtalar fusion when the calcaneal tuberosity is amendable to cannulated screw fixation to treat these complex calcaneal fractures. Our technique offers advantages compared to other techniques in that it avoids screw traffic, allows easy bony compression of the subtalar joint, and minimizes soft tissue damage via percutaneous screw fixation. Fourteen fractured calcanei in 12 patients underwent our technique and all achieved bony union with a median time to fusion of 107.5 days (range, 54-530 days). Eight patients returned to work with the remaining 4 patients having an unknown work status at last follow-up, although 2 of these 4 patients resumed normal activities. Only 1 patient experienced a complication, which was an infection after achieving bony union, and was treated with successful hardware removal and our infection protocol. Overall, we conclude our surgical technique offers a successful option in the treatment of DIACFs when the calcaneal tuberosity is amendable to cannulated screw fixation.

Secondary Effects of the Rupture and Reconstruction of the Interosseous Talocalcaneal Ligament on the Peritalar Joints.

BACKGROUND The interosseous talocalcaneal ligament (ITCL) is the main soft-tissue contributor to subtalar joint stability. The role of ITCL reconstruction in retaining this stability is minimally reported. Therefore, we conducted this study to investigate the effects of rupture and reconstruction of the ITCL on the subtalar and peritalar joints. MATERIAL AND METHODS This experimental study randomly divided 72 rabbits into 3 equal groups of 24 rabbits each. Group I underwent reconstruction surgery, group II underwent resection, and group III was the control group. The cartilages between the talocrural and calcaneocrural joints, and between the subtalar and talonavicular joints on both sides were assessed by gross observation, ink staining, histology, and immunohistochemistry at weeks 4, 8, 16, and 32, postoperatively. RESULTS In group II, the quantitative ink staining analysis revealed degeneration of the articular cartilages on the talonavicular joint (T=2.070, P=0.038) and the posterior subtalar joint (T=2.121, P=0.034) compared with the 2 sides of the same rabbit at 4 and 8 postoperative weeks. Comparing the operated sides of all the groups showed the posterior subtalar joints (Hc=9.563, P=0.008) and talonavicular joints (Hc=9.714, P=0.008) had an obvious difference at postoperative week 4; and in the calcaneocrural joints (Hc=6.750, P=0.034), it was noticed at postoperative week 8. Histology and immunohistochemistry findings confirm these observations. CONCLUSIONS An ITCL resection can lead to the progressive degeneration of the talonavicular and posterior subtalar joints, while an ITCL reconstruction can be beneficial in restoring the stability of these joints, preventing or postponing their degeneration, and protecting the articular cartilages.

Ultrasound Imaging Guide for Assessment of the Intrinsic Ligaments Stabilizing the Subtalar and Midtarsal Joints.

Ligament injuries around the subtalar, talocalcaneonavicular, and calcaneocuboid joints are often underestimated on clinical and imaging findings during investigation of patients with ankle and foot injuries. Because a delayed diagnosis of midtarsal ligament tears may lead to chronic pain and functional disability, an in-depth knowledge of the complex regional anatomy and of the appropriate ultrasound scanning technique is a prerequisite for evaluating these structures and avoiding misdiagnoses. The objective of this article is twofold: to describe the relevant anatomy and biomechanics related to the ligaments that stabilize the subtalar, talocalcaneonavicular, and calcaneocuboid joints, and to illustrate reasoned landmark-based scanning techniques to provide a systematic examination of these ligaments and thus make ultrasound an effective tool for assessment of patients with suspected subtalar or midtarsal sprain.

Treatment of closed subtalar joint dislocation: A case report and literature review.

Subtalar dislocation is defined as a separation of the talocalcaneal and talonavicular articulations, commonly caused by high-energy mechanisms, which include falls from height, motor vehicle crashes, and twisting leg injuries. The dislocations are divided into medial, lateral, anterior, and posterior types on the basis of the direction in which the distal part of the foot has shifted in relation to the talus. The most common type is medial dislocation resulted from inversion injury. Subtalar dislocation may accompany with other fractures. Physical examination must be performed carefully to assess for neurovascular compromise. Most of the subtalar dislocations can be treated with closed reduction under sedation. If this is not possible, open reduction without further delay should be conducted. After primary treatment, X-ray and computed tomography scan should be performed to evaluate the alignment and the fractures. We report a 37-year-old male patient sustained a subtalar dislocation without any bony injury when he was playing football. The patient was successfully treated by closed reduction, and a good alignment was observed at the last follow-up. The pathogenesis and treatment method of this case were analyzed, and the related literature were reviewed, which provided a reference for future clinical treatment.

Tibiotalocalcaneal Arthrodesis Utilizing a Titanium Intramedullary Nail With an Internal Pseudoelastic Nitinol Compression Element: A Retrospective Case Series of 33 Patients.

Nitinol has been shown to generate durable compression under loading via pseudoelastic shape memory. The purpose of this study was to evaluate the effectiveness of a hindfoot arthrodesis nail with an internal pseudoelastic nitinol compression element. Patients who had undergone tibiotalocalcaneal arthrodesis from 2013 to 2016 were identified at 2 tertiary referral centers (12-week follow-up minimum). Patients managed with a tibiotalocalcaneal nail with an internal nitinol compression element were identified for review. Sagittal computed tomographic scan reformats were reviewed to calculate a percentage of joint surface bony union. Intraoperative and postoperative radiographs were compared to calculate postoperative screw position change generated by the nitinol element, a surrogate for postoperative unloading of compressive forces. Thirty-three patients were included in analysis and 81% of patients had successful union of both tibiotalar and subtalar joints. Overall, 90% of all arthrodesis surfaces united. The union rate of arthrodesis surfaces among patients without Charcot osteoarthropathy was 94%. A history of Charcot was identified as a risk factor for subtalar nonunion (p = .04) and was associated with less complete computed tomography-based tibiotalar union: 94% versus 71% (p < .01). The posterior-to-anterior screw translated an average of 3.9 mm proximally relative to the rigid portion of the nail from intraoperative to initial postoperative radiographs (p < .0001). High rates of computed tomography-confirmed union were demonstrated in the face of challenging clinical scenarios. Shortening of the pseudoelastic nitinol element occurs early in the postoperative period, indicating continued unloading of the nitinol compression element through the arthrodesis sites after initial implantation.

Open Talar Neck Fracture With Medial Subtalar Joint Dislocation: A Case Report.

We present a unique case of an open talar neck fracture with medial subtalar joint dislocation. This rare and traumatic injury was treated with immediate open reduction of the subtalar joint and open reduction internal fixation of the talar neck fracture. After a follow-up of 2.2 years, highlighted by numerous complications including posttraumatic arthritis, soft tissue abscess, and fibrotic adhesions, the patient recovered sufficiently to return full activity.

Core curriculum case illustration: medial peritalar dislocation.

This is the 29th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at: http://www.aseronline.org/curriculum/toc.htm .

Isolated Acute Traumatic Subtalar Dislocations: Review of 13 Cases at a Mean Follow-Up of 6 Years and Literature Review.

Isolated acute traumatic subtalar dislocations are quite rare. They correspond to talotarsal dislocation, including the talonavicular and talocalcaneal joints. The purpose of the present study was to evaluate the functional and radiologic outcomes of the treatment of acute traumatic isolated subtalar dislocations. The present retrospective study included 13 patients who had sustained isolated subtalar dislocations during a 10-year period. Of the 13 cases, 10 (76.9%) were medial dislocations and 3 (23.1%) were lateral dislocations. All the patients underwent immediate closed reduction under anesthesia followed by immobilization. No open reduction was required. The mean follow-up period was 72.6 (range 24.4 to 124.8) months. The mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score was 80.1 of 100 (range 66 to 90). The score result was good in 69% of cases and poor in 31% of cases. The subtalar mobility was reduced for 8 (61.5%) patients and significantly affected the American Orthopaedic Foot and Ankle Society score (p = .002). Subtalar osteoarthritis was present in 6 (46.1%) cases with talonavicular osteoarthritis in 3 (23.1%) cases. No cases of avascular necrosis of the talus were noted. In accordance with the published data, the prognosis of isolated acute traumatic subtalar dislocations is favorable. Medial dislocations are more frequent than lateral dislocations. Emergent closed reduction makes it possible to remove soft tissue injuries. The risk of post-traumatic subtalar osteoarthritis is significant, even without an initial subtalar lesion. A postreduction computed tomography scan will enable the diagnosis of osteochondral lesions.

Unstable Open Posterior Subtalar Dislocation Treated With a Ring External Fixator: A Case Report and Review of the Literature.

Traumatic dislocation of the subtalar joint is an infrequently occurring injury, with open true posterior dislocation an even rarer injury. We describe our treatment of a young motorcyclist who was brought into hospital after a road traffic accident, having sustained an open posterior subtalar dislocation. After initial reduction and resuscitation in the emergency department, he was taken to the operating theater for emergent wound debridement and external fixation of his ankle using a unilateral external fixator device. After 2 subsequent repeat debridements, this was changed to a ring external fixator device, followed by split-thickness skin grafting of his wound. He was allowed full weightbearing and was discharged from hospital 10 days after his last operation. He continued to improve clinically at his outpatient appointments to the 1-year follow-up point, with his external fixator removed at 6 weeks postoperatively. At the last follow-up appointment, he had successfully returned to his previous employment. To the best of our knowledge, only 1 other description of an open posterior dislocation has been reported, which was managed nonoperatively after wound debridement. Ours is the first reported case of an open posterior dislocation managed surgically using a ring external fixator. We believe the ability to allow immediate weightbearing resulting from the additional stability provided by this type of fixation is advantageous, with a theoretical reduction in the risk of periarticular osteoporosis and calf muscle atrophy. The early mobilization afforded by this treatment is hoped to improve the typically poor long-term outcomes for these patients.

Operative Versus Nonoperative Treatment for Displaced Intra-Articular Calcaneal Fractures: A Meta-Analysis of Randomized Controlled Trials.

The purpose of the present study was to perform an updated meta-analysis of the operative versus nonoperative treatment of displaced intra-articular calcaneal fractures in adults. We searched the Cochrane Library, MEDLINE, EMBASE, and Google Scholar for eligible studies. All published randomized controlled trials comparing operative with nonoperative treatment for displaced intra-articular calcaneal fractures were eligible. The meta-analysis was performed using RevMan, version 5.0, software. Seven studies assessing 824 patients were eligible for the meta-analysis. The pooled results indicated no significant differences between the 2 groups with regard to the functional results. The incidence of complications was 25.0% (80 of 319) in the operative group and 16.6% (55 of 330) in the nonoperative group (relative risk 1.53, 95% confidence interval 1.13 to 2.08; p = .006) with a significant difference. The rate of subtalar arthrodesis was significantly lower in the operative group than in the nonoperative group. The current evidence is still insufficient to ascertain whether operative treatment is superior to nonoperative treatment for displaced intra-articular calcaneal fractures. Operative treatment can reduce the risk of late subtalar arthrodesis but is associated with a greater risk of complications. The small sample size and the great heterogeneity of the included studies made it difficult to draw conclusions regarding some of the combined results. Furthermore, more high-quality, randomized controlled trials with long-term follow-up data on this issue are required to provide evidence for surgeons to make an informed decision.

Fracture of the Posterior Process of the Talus With Concomitant Subtalar Dislocation.

Fracture of the posterior process of the talus with concomitant subtalar dislocation is rare; thus, the mechanism of injury, appropriate treatment, and prognosis are unclear. We report the case of a 50-year-old male with a fracture of the posterior process of the talus with concomitant subtalar dislocation that was recognized early and successfully treated operatively.

Vascularized Pedicled Fibula Onlay Bone Graft Augmentation for Complicated Tibiotalocalcaneal Arthrodesis With Retrograde Intramedullary Nail Fixation: A Case Series.

Tibiotalocalcaneal arthrodesis stabilized with retrograde intramedullary nail fixation is associated with a high incidence of complications. This is especially true when performed with a bulk structural allograft and poor soft tissue quality. In select high-risk limb salvage cases, we have augmented tibiotalocalcaneal arthrodesis procedures stabilized using retrograde intramedullary nail fixation with a vascularized pedicled fibular onlay bone graft. We present the data from 10 such procedures with a mean follow-up period of 10.9 ± 5.4 (range 6 to 20) months involving 10 patients (9 males and 1 female). The etiology was avascular osteonecrosis of the talus and/or distal tibia and a resultant large volume cavitary bone defect (8 ankles), severe equinocavovarus contracture (1 ankle), and failed total ankle replacement (1 ankle). A frozen femoral head bulk allograft was used twice, a whole frozen talus allograft once, and a freeze-dried calcaneal allograft once. The fibula was mobilized with intact musculoperiosteal perforating branches of the peroneal artery as a vascularized pedicle onlay bone graft fixated with a screw and washer construct. The mean fibular graft length was 10.2 ± 2.3 cm. The mean interval to radiographic fusion was 2.6 ± 0.6 months and to weightbearing was 3.1 ± 1.4 months. Two stable bulk allograft-host bone and fibular graft-host bone nonunions occurred after intramedullary nail hardware failure. Tibiotalocalcaneal arthrodesis augmented by vascularized pedicled fibular graft stabilized with retrograde compression intramedullary nail fixation offers a reliable option for complex salvage situations when few other options exist.

Current management options for displaced intra-articular calcaneal fractures: Non-operative, ORIF, minimally invasive reduction and fixation or primary ORIF and subtalar arthrodesis. A contemporary review.

BACKGROUND: Management of Displaced Intra-articular Calcaneal Fractures (DIACFs) continues to be technically demanding. The literature has not been definitive in its guidance for surgeons dealing with these injuries. Recent publications have further added to the lack of clarity. This review is intended to summarise the present state of knowledge, and provide some genuine guidance for clinicians. OBJECTIVES: To review previous research, focussing on articles published within the last fifteen years, and summarise the findings to aid surgeons in managing DIACFs with choosing best management for patients. METHODS: We reviewed the best evidence and literature, focussing on articles published within the last fifteen years, and summarised findings into workable recommendations. Variables of (1) patient, (2) the associated soft tissue injury and (3) the fracture characteristics were used to aid surgeons in choosing the best of the available options for each patient that presents with a DIACF. AUTHORS SUMMARY: Management of DIACFs can best be divided into four broad categories: (i) non-operative management, (ii) open reduction and internal fixation, (iii) minimally invasive reduction and fixation, and (iv) primary subtalar arthrodesis. The evolution of the literature would suggest orthopaedic surgeons managing calcaneus fractures should have an expert's knowledge, surgical expertise and the latest techniques to cover these four options, to tailor the treatment of DIACFs to the individual patient.

Subtle anterior subtalar dislocation.

Subtalar dislocations are uncommon injuries, and anterior subtalar dislocations are extremely rare. Only 7 cases have been reported in detail in the literature, but all were associated with substantial displacement immediately apparent on radiographs. We report a case of a subtle anterior subtalar dislocation that was missed on initial plain films but was subsequently treated successfully with closed reduction.

Primary subtalar joint arthrodesis for comminuted fractures of the calcaneus.

Severely comminuted intra-articular calcaneal fractures often culminate in subtalar arthrosis and stiffness even after operative reduction. In some instances, subtalar arthrodesis is necessary to reduce the symptoms. Primary subtalar arthrodesis for these fractures has gained acceptance in recent years. However, few definite predictors of functional outcome after primary fusion have been found. A series of 17 patients with highly comminuted fractures were studied to determine which radiographic parameters were predictive of functional outcome. The American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale score was obtained at an average of 34 (range 12 to 157) months after arthrodesis. Radiographic measurements included the talocalcaneal, calcaneal inclination, talo-first metatarsal, and Böhler's angles, and the height of the tibial plafond, width of the calcaneus, and the presence of a medial step-off on the injured and uninjured foot. The mean Ankle-Hindfoot scale score was 78 (range 56 to 92), and the mean visual analog score was 1.9 (0 to 4). Statistically significant associations were noted between greater postoperative function and increasing age (p = .028), the quality of restoration of Böhler's angle (p = .038), and the talocalcaneal angle (p = .049). No patient had nonunion. The results of the present study suggest that the outcomes after primary arthrodesis of the subtalar joint are favorable, in particular, when the radiographic relationships of the hindfoot have been restored.

Early minimally invasive percutaneous fixation of displaced intra-articular calcaneal fractures with a percutaneous angle stable device.

The Minimally Invasive Reduction and Osteosynthesis System(®) (MIROS) is a percutaneous angle stable device for the treatment of fractures. The aim of the present study was to evaluate the clinical and radiographic results of an early minimally invasive osteosynthesis with the MIROS device. A total of 40 consecutive patients were treated for an intra-articular fracture of the calcaneus. We evaluated the clinical and radiographic outcomes after treatment of intra-articular calcaneal fractures with the MIROS hardware. Soft tissue damage was noted. The patients completed the American Orthopaedic Foot and Ankle Society survey at 12 and 24 months and underwent radiologic evaluations. A statistically significant association between the American Orthopaedic Foot and Ankle Society score and type of soft tissue lesion. A Sanders type II, III, and IV fracture was found in 15, 20, and 15 of 50 fractures, respectively. Postoperatively, restoration of the posterior facet was reached in 13 of 15, 18 of 20, and 11 of 15 with a type II, III, and IV fracture, respectively. The American Orthopaedic Foot and Ankle Society scale mean score was 85 at the final follow-up visit. No significant association was found between the score and the preoperative variables (p > .09), although patients with bilateral fractures had a significantly lower score. The MIROS device for early treatment of intra-articular calcaneus fractures resulted in excellent clinic and radiologic results. The standardized technique we have reported, with the elastic wires acting as a girder for the fractured and displace subtalar joint and the collapsed lateral calcaneal wall, has permitted early weightbearing with positive stimuli for the bone healing. The drainage effect of the percutaneous wires likely prevented compartment syndrome when applied within the first hours after the trauma.

Intraarticular fractures of calcaneus - current concepts of treatment.

Fractures of calcaneus are the most common among all tarsal bone fractures. Such injuries are most often produced by large forces, while accompanying soft tissue trauma makes them complicated and difficult to treat. Due to complex structure of the foot and talocalcaneal joint all injuries to this area constitute an important orthopedic problem, as improper treatment or lack thereof leads to gait impairment, particularly with regard to moving on uneven surface. In this work we presented the problem of intraarticular calcaneal fractures with particular consideration paid to methods of its treatment. We also mentioned the problem of complications after conservative and surgical treatment as well as methods of their prevention.

Subtalar Osteochondral Lesions: Diagnosis, Indications, and Prognosis.

Although most commonly found in the knee, elbow, and talar dome, osteochondral lesions can also be found in the subtalar joint and can occur due to either high or low energy trauma. Diagnosis of these lesions in the subtalar joint is typically confirmed with advanced imaging such as computerized tomography and MRI. Although there are a few published case reports, there is otherwise very limited literature on the prevalence, treatment options, prognosis, or outcomes for patients with osteochondral lesions of the subtalar joint, and thus further research is required in this area.