Luxaciones periastragalinas: análisis de una serie de casos. Nuestro algoritmo de tratamiento urgente / Subtalar dislocations: Analysis of a case series. Our urgent treatment algorithm

Introducción y objetivos: Las luxaciones periastragalinas son una entidad poco frecuente (<1%) de las lesiones traumáticas del pie. Se produce una pérdida de relación anatómica entre astrágalo, calcáneo y escafoides. Solo hay pequeñas series publicadas. Material y métodos: Presentamos los casos de una serie de pacientes (N=13) con luxaciones periastragalinas en los que se realizó un análisis descriptivo de las principales variables epidemiológicas, clínicas y radiológicas, a partir de las cuales se propone un algoritmo de tratamiento urgente. Se excluyeron los casos con fracturas del cuello del astrágalo, cuerpo del calcáneo o fracturas-luxación de Chopart aisladas. Resultados: La mediana de edad fue de 48,5 años con predominio del sexo masculino (69,23%). Cinco pacientes sufrieron caídas-entorsis sobre el tobillo y los 8 restantes mecanismos de alta energía. Las luxaciones mediales (9) predominaron sobre las laterales (4). Además, 4 pacientes presentaron luxaciones abiertas, 2 de ellas tipo IIIC que precisaron amputación. Se solicitó TC en un 76,93% de pacientes y 10 presentaron lesiones óseas asociadas del pie. Se realizó cirugía mediante reducción abierta en todas las lesiones abiertas y en un caso en el que fracasó la reducción cerrada. Cinco pacientes precisaron fijador externo tipo delta. Se objetivó esclerosis subcondral articular en un 77,77% de los casos; si bien solo uno precisó artrodesis subtalar. Conclusiones: Las luxaciones periastragalinas son una urgencia traumatológica y precisan una reducción precoz e inmovilización posterior. La fijación externa temporal transarticular es una buena opción de inmovilización en luxaciones abiertas. Son lesiones graves con alta probabilidad de artrosis precoz.(AU)

Introduction and objectives: Subtalar dislocations are a rare entity (<1%) in traumatic foot injuries. There is a loss of anatomical relationship between the talus, calcaneus and scaphoid. There are only small-published series. Material and methods: We present a series of patients (N=13) with subtalar dislocations in which a descriptive analysis of the main epidemiological, clinical and radiological variables was carried out, from which an urgent treatment algorithm is proposed. Cases with fractures of the neck of the talus, body of the calcaneus, or isolated Chopart fracture-dislocations were excluded. Results: The median age was 48.5 years with a predominance of males (69.23%). Five patients suffered falls or sprained ankles and the other eight suffered high-energy mechanisms. The medial dislocations (nine) predominated over the lateral ones (four). In addition, four patients presented open dislocations, two of them type IIIC that required amputation. CT scans were requested in 76.93% of patients and 10 presented associated bone lesions of the foot. Open reduction surgery was performed in all open lesions and in one case in which closed reduction failed. Five patients required a delta-type external fixator. Subchondral articular sclerosis was observed in 77.77% of cases; although only one required subtalar arthrodesis. Conclusions: Subtalar dislocations are a traumatic emergency that require early reduction and subsequent immobilization. Transarticular temporary external fixation is a good immobilization option in open dislocations. They are serious lesions with a high probability of early osteoarthritis.(AU)

[Translated article] Subtalar dislocations: Analysis of a case series. Our urgent treatment algorithm / Luxaciones periastragalinas: análisis de una serie de casos. Nuestro algoritmo de tratamiento urgente

Introducción y objetivos: Las luxaciones periastragalinas son una entidad poco frecuente (<1%) de las lesiones traumáticas del pie. Se produce una pérdida de relación anatómica entre astrágalo, calcáneo y escafoides. Solo hay pequeñas series publicadas. Material y métodos: Presentamos los casos de una serie de pacientes (N=13) con luxaciones periastragalinas en los que se realizó un análisis descriptivo de las principales variables epidemiológicas, clínicas y radiológicas, a partir de las cuales se propone un algoritmo de tratamiento urgente. Se excluyeron los casos con fracturas del cuello del astrágalo, cuerpo del calcáneo o fracturas-luxación de Chopart aisladas. Resultados: La mediana de edad fue de 48,5 años con predominio del sexo masculino (69,23%). Cinco pacientes sufrieron caídas-entorsis sobre el tobillo y los 8 restantes mecanismos de alta energía. Las luxaciones mediales (9) predominaron sobre las laterales (4). Además, 4 pacientes presentaron luxaciones abiertas, 2 de ellas tipo IIIC que precisaron amputación. Se solicitó TC en un 76,93% de pacientes y 10 presentaron lesiones óseas asociadas del pie. Se realizó cirugía mediante reducción abierta en todas las lesiones abiertas y en un caso en el que fracasó la reducción cerrada. Cinco pacientes precisaron fijador externo tipo delta. Se objetivó esclerosis subcondral articular en un 77,77% de los casos; si bien solo uno precisó artrodesis subtalar. Conclusiones: Las luxaciones periastragalinas son una urgencia traumatológica y precisan una reducción precoz e inmovilización posterior. La fijación externa temporal transarticular es una buena opción de inmovilización en luxaciones abiertas. Son lesiones graves con alta probabilidad de artrosis precoz.(AU)

Introduction and objectives: Subtalar dislocations are a rare entity (<1%) in traumatic foot injuries. There is a loss of anatomical relationship between the talus, calcaneus and scaphoid. There are only small-published series. Material and methods: We present a series of patients (N=13) with subtalar dislocations in which a descriptive analysis of the main epidemiological, clinical and radiological variables was carried out, from which an urgent treatment algorithm is proposed. Cases with fractures of the neck of the talus, body of the calcaneus, or isolated Chopart fracture-dislocations were excluded. Results: The median age was 48.5 years with a predominance of males (69.23%). Five patients suffered falls or sprained ankles and the other eight suffered high-energy mechanisms. The medial dislocations (nine) predominated over the lateral ones (four). In addition, four patients presented open dislocations, two of them type IIIC that required amputation. CT scans were requested in 76.93% of patients and 10 presented associated bone lesions of the foot. Open reduction surgery was performed in all open lesions and in one case in which closed reduction failed. Five patients required a delta-type external fixator. Subchondral articular sclerosis was observed in 77.77% of cases; although only one required subtalar arthrodesis. Conclusions: Subtalar dislocations are a traumatic emergency that require early reduction and subsequent immobilization. Transarticular temporary external fixation is a good immobilization option in open dislocations. They are serious lesions with a high probability of early osteoarthritis.(AU)

[Translated article] SCIWORA in children. A rare clinical entity: Ambispective study / SCIWORA. Una rara entidad clínica en la población pediátrica. Estudio ambispectivo

Introducción y objetivos: Las luxaciones periastragalinas son una entidad poco frecuente (<1%) de las lesiones traumáticas del pie. Se produce una pérdida de relación anatómica entre astrágalo, calcáneo y escafoides. Solo hay pequeñas series publicadas. Material y métodos: Presentamos los casos de una serie de pacientes (N=13) con luxaciones periastragalinas en los que se realizó un análisis descriptivo de las principales variables epidemiológicas, clínicas y radiológicas, a partir de las cuales se propone un algoritmo de tratamiento urgente. Se excluyeron los casos con fracturas del cuello del astrágalo, cuerpo del calcáneo o fracturas-luxación de Chopart aisladas. Resultados: La mediana de edad fue de 48,5 años con predominio del sexo masculino (69,23%). Cinco pacientes sufrieron caídas-entorsis sobre el tobillo y los 8 restantes mecanismos de alta energía. Las luxaciones mediales (9) predominaron sobre las laterales (4). Además, 4 pacientes presentaron luxaciones abiertas, 2 de ellas tipo IIIC que precisaron amputación. Se solicitó TC en un 76,93% de pacientes y 10 presentaron lesiones óseas asociadas del pie. Se realizó cirugía mediante reducción abierta en todas las lesiones abiertas y en un caso en el que fracasó la reducción cerrada. Cinco pacientes precisaron fijador externo tipo delta. Se objetivó esclerosis subcondral articular en un 77,77% de los casos; si bien solo uno precisó artrodesis subtalar. Conclusiones: Las luxaciones periastragalinas son una urgencia traumatológica y precisan una reducción precoz e inmovilización posterior. La fijación externa temporal transarticular es una buena opción de inmovilización en luxaciones abiertas. Son lesiones graves con alta probabilidad de artrosis precoz.(AU)

Introduction and objectives: Subtalar dislocations are a rare entity (<1%) in traumatic foot injuries. There is a loss of anatomical relationship between the talus, calcaneus and scaphoid. There are only small-published series. Material and methods: We present a series of patients (N=13) with subtalar dislocations in which a descriptive analysis of the main epidemiological, clinical and radiological variables was carried out, from which an urgent treatment algorithm is proposed. Cases with fractures of the neck of the talus, body of the calcaneus, or isolated Chopart fracture-dislocations were excluded. Results: The median age was 48.5 years with a predominance of males (69.23%). Five patients suffered falls or sprained ankles and the other eight suffered high-energy mechanisms. The medial dislocations (nine) predominated over the lateral ones (four). In addition, four patients presented open dislocations, two of them type IIIC that required amputation. CT scans were requested in 76.93% of patients and 10 presented associated bone lesions of the foot. Open reduction surgery was performed in all open lesions and in one case in which closed reduction failed. Five patients required a delta-type external fixator. Subchondral articular sclerosis was observed in 77.77% of cases; although only one required subtalar arthrodesis. Conclusions: Subtalar dislocations are a traumatic emergency that require early reduction and subsequent immobilization. Transarticular temporary external fixation is a good immobilization option in open dislocations. They are serious lesions with a high probability of early osteoarthritis.(AU)

Effects of added trunk load on the in vivo kinematics of talocrural and subtalar joints during landing.

BACKGROUND: Landing from heights is a common movement for active-duty military personnel during training. And the additional load they carry while performing these tasks can affect the kinetics and ankle kinematic of the landing. Traditional motion capture techniques are limited in accurately capturing the in vivo kinematics of the talus. This study aims to investigate the effect of additional trunk load on the kinematics of the talocrural and subtalar joints during landing, using a dual fluoroscopic imaging system (DFIS). METHODS: Fourteen healthy male participants were recruited. Magnetic resonance imaging was performed on the right ankle of each participant to create three-dimensional (3D) models of the talus, tibia, and calcaneus. High-speed DFIS was used to capture the images of participants performing single-leg landing jumps from a height of 40 cm. A weighted vest was used to apply additional load, with a weight of 16 kg. Fluoroscopic images were acquired with or without additional loading condition. Kinematic data were obtained by importing the DFIS data and the 3D models in virtual environment software for 2D-3D registration. The kinematics and kinetics were compared between with or without additional loading conditions. RESULTS: During added trunk loading condition, the medial-lateral translation range of motion (ROM) at the talocrural joint significantly increased (p < 0.05). The subtalar joint showed more extension at 44-56 ms (p < 0.05) after contact. The subtalar joint was more eversion at 40-48 ms (p < 0.05) after contact under the added trunk load condition. The peak vertical ground reaction force (vGRF) significantly increased (p < 0.05). CONCLUSIONS: With the added trunk load, there is a significant increase in peak vGRF during landing. The medial-lateral translation ROM of the talocrural joint increases. And the kinematics of the subtalar joint are affected. The observed biomechanical changes may be associated with the high incidence of stress fractures in training with added load.

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.

Extrapulmonary, Chronic Septic Arthritis From Mycobacterium tuberculosis in the Ankle and Subtalar Joints.

In the United States, rates of Mycobacterium tuberculosis infection have been declining for decades. Osteoarticular tuberculosis of the ankle is rarely observed. We present the case of a 65-year-old man who immigrated to the United States from India 24 years before the onset of symptoms. The patient initially reported atraumatic swelling and pain of the left ankle and foot and was treated for venous insufficiency. Later, the patient was referred to a nonsurgical orthopaedic clinic for additional workup and was found to have elevated inflammatory markers. MRI showed septic arthritis and osteomyelitis of the talus, distal tibia, and calcaneus. Joint aspiration revealed elevated white blood cell counts with predominately PMNs. The patient was then referred to an orthopaedic foot and ankle surgeon and underwent extensive irrigation and débridement. The patient was discharged on empiric antibiotics. Culture results from the original joint aspirate returned 14 days after surgery as positive for acid-fast bacillus, later identified as M tuberculosis by sequencing. Empiric antibiotics were discontinued, and the patient was started on appropriate antituberculotic therapy. This case report illustrates the challenge in the diagnosis of skeletal tuberculosis and the importance of including this condition on the differential for patients with atypical foot and ankle presentations.

Enhancing Post-Surgical Rehabilitation Outcomes in Patients with Chronic Ankle Instability: Impact of Subtalar Joint Axis Balance Exercises Following Arthroscopic Modified Broström Operation.

Background and Objectives: This study aimed to evaluate the effects of subtalar joint axis-based balance exercises on the anterior talofibular ligament (ATFL) thickness, ankle strength, and ankle stability after an arthroscopic modified Broström operation (AMBO) for chronic ankle instability (CAI). Materials and Methods: The study included 47 patients diagnosed with CAI who underwent AMBO and were randomly divided into three groups: control (n = 11), general balance exercise (n = 17), and subtalar joint axis balance exercise (n = 19), regardless of the affected area. Participants in the exercise rehabilitation group performed exercises for 60 min twice a week for six weeks, starting six weeks after AMBO. ATFL thickness, ankle strength, and ankle dynamic stability were measured using musculoskeletal ultrasonography, Biodex, and Y-balance test, respectively, before and after treatment. Results: Compared with the remaining groups, the subtalar joint axis balance exercise group had reduced ATFL thickness (p = 0.000), improved ankle strength for eversion (p = 0.000) and inversion (p = 0.000), and enhanced ankle stability (p = 0.000). Conclusions: The study results suggest that subtalar joint axis-based balance exercises may contribute to the early recovery of the ankle joint after AMBO.

Complications in Total Ankle Replacement.

The debate between ankle arthrodesis and total ankle replacement for patients with end-stage arthritis of the ankle joint is an ongoing topic in orthopedic surgery. Ankle arthrodesis, or fusion, has been the traditional treatment for ankle arthritis. It involves fusing the bones of the ankle joint together, eliminating the joint and creating a solid bony union. Arthrodesis is effective in reducing pain in the ankle, but it results in a loss of ankle motion. This can increase the load on adjacent joints, such as the subtalar joint, which may lead to accelerated degeneration and arthritis in those joints over time.

Biomechanical Effects of Subtalar Joint Fusion and Medial Ligament Reconstruction in Simulated Progressive Collapsing Foot Deformity.

BACKGROUND: The purpose of this study is to investigate the biomechanical effect of medial displacement calcaneal osteotomy (MDCO), subtalar joint fusion (SF), and medial ligament reconstruction (MLR: deltoid-spring ligament) in a severe flatfoot model. We hypothesized that (1) combination of MDCO and SF improves the tibiotalar and foot alignment in severe progressive collapsing foot deformity (PCFD) cadaver model. (2) However, if a residual valgus heel alignment remains after MCDO and SF, it can lead to increased medial ligament strain, foot malalignment, and tibiotalar valgus tilt, which will be mitigated by the addition of MLR. METHODS: Ten fresh-frozen cadaveric foot specimens were used to create a severe flatfoot model. The foot alignment changes, including the talo-first metatarsal angle in the axial and sagittal planes, subtalar angle, and tibiotalar angle in the coronal plane, were measured. The angles were measured at the initial condition, after creating the severe flatfoot model, and after each successive reconstructive procedure in the following order: (1) MDCO, (2) SF, and (3) MLR. RESULTS: Tibiotalar valgus tilt was decreased with the MDCO procedure: 4.4 vs 1.0 degrees (P = .04). Adding in situ SF to the MDCO led to increased tibiotalar tilt to 2.5 degrees was different from the initial condition (P = .01). Although the tibiotalar valgus tilt was significantly decreased after adding the MLR to the MDCO/SF procedure compared with the severe flatfoot model (0.8 vs 4.4 degrees, P = .03), no significant difference in the tibiotalar valgus tilt was observed between MDCO/SF and MDCO/SF with MLR. CONCLUSION: Our results demonstrated that MDCO significantly improved forefoot abduction and medial arch alignment, with no significant additional improvement observed with addition of SF. Following SF, a residual valgus heel alignment can contribute to subsequent tibiotalar valgus tilt. The addition of MLR did not show significantly decreased tibiotalar valgus tilt following SF. CLINICAL RELEVANCE: Residual valgus heel alignment after subtalar joint fusion in the surgical treatment of PCFD can lead to increased medial ligament strain. Although MLR might be considered for providing medial stability, it may not necessarily prevent the development of tibiotalar valgus tilt.

Reaming for Tibiotalocalcaneal Nailing Removes Only 10% of the Ankle and Subtalar Joints.

OBJECTIVES: Tibiotalocalcaneal (TTC) nailing in the setting of acute ankle trauma has become increasingly popular. No consensus exists as to whether formal joint preparation is necessary, although there is some concern that residual motion at unprepared joints may lead to implant loosening and/or breakage. The objective of this study was to quantify the proportion of tibiotalar and subtalar articular surface destruction that occurs during reaming for TTC nail fixation. METHODS: Twelve cadaver lower extremities were procured. The specimens were pinned into neutral ankle and hindfoot alignment. A guidewire was inserted under fluoroscopy, followed by a 12-mm opening reamer. The specimens were then dissected, exposing the tibial plafond, talar dome, posterior facet of the talus, and posterior facet of the calcaneus. Images of each joint were obtained, and ImageJ software was used to calculate the total joint surface area and the area of articular destruction. RESULTS: The mean proportion of articular cartilage destruction was 9.3%, 10.3%, 8.9%, and 10.3% for the tibial plafond, talar dome, posterior facets of the talus, and posterior facets of the calcaneus, respectively. No joint destruction was observed in the middle facets of the subtalar joint. CONCLUSIONS: Reaming for TTC nail placement violates approximately 10% of each articular surface of the tibiotalar and subtalar joints. Retention of 90% of the articular surface may allow for residual motion at the joints and therefore potentially substantial stress on the implant. Formal joint preparation for the purposes of achieving fusion during TTC nail placement may be beneficial to prevent implant loosening or breakage.

Acute effect of foot strike patterns on in vivo tibiotalar and subtalar joint kinematics during barefoot running.

BACKGROUND: Foot kinematics, such as excessive eversion and malalignment of the hindfoot, are believed to be associated with running-related injuries. The majority of studies to date show that different foot strike patterns influence these specific foot and ankle kinematics. However, technical deficiencies in traditional motion capture approaches limit knowledge of in vivo joint kinematics with respect to rearfoot and forefoot strike patterns (RFS and FFS, respectively). This study uses a high-speed dual fluoroscopic imaging system (DFIS) to determine the effects of different foot strike patterns on 3D in vivo tibiotalar and subtalar joints kinematics. METHODS: Fifteen healthy male recreational runners underwent foot computed tomography scanning for the construction of 3-dimensional models. A high-speed DFIS (100 Hz) was used to collect 6 degrees of freedom kinematics for participants' tibiotalar and subtalar joints when they adopted RFS and FFS in barefoot condition. RESULTS: Compared with RFS, FFS exhibited greater internal rotation at 0%-20% of the stance phase in the tibiotalar joint. The peak internal rotation angle of the tibiotalar joint under FFS was greater than under RFS (p < 0.001, Cohen's d = 0.92). RFS showed more dorsiflexion at 0%-20% of the stance phase in the tibiotalar joint than FFS. RFS also presented a larger anterior translation (p < 0.001, Cohen's d = 1.28) in the subtalar joint at initial contact than FFS. CONCLUSION: Running with acute barefoot FFS increases the internal rotation of the tibiotalar joint in the early stance. The use of high-speed DFIS to quantify the movement of the tibiotalar and subtalar joint was critical to revealing the effects of RFS and FFS during running.

The morphology of osseous structure in subtalar joint with chronic ankle instability.

BACKGROUND: Osseous structures have been demonstrated as risk factors for chronic ankle instability (CAI). Previously, the researchers only focused on the osseous structures of ankle, but ignored the osseous structures of subtalar joint(STJ). Accordingly, the aim of our study was to investigate the morphological characteristics of STJ osseous structures in CAI. METHODS: 52 patients with CAI and 52 sex- and age- matched control subjects were enrolled from The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University. The lateral radiographs of ankle in weight-bearing were used to compare the diversity of the two groups. Specifically, The Length of calcaneus, Calcaneal facet height and Absolute foot height, Böhler's angle, Gissane's angle, Calcaneal inclination angle, Talocalcaneal angle, Tibiotalar angle, Tibiocalcaneal angle, Talar-horizontal angle, talar declination angle, facet inclination angle were gauged in the two groups. RESULTS: The Böhler's angle, Calcaneal inclination, Talocalcaneal angle, Tibiotalar angle, Talar-horizontal angle, Talar declination angle, Facet inclination angle and Absolute foot height of CAI group were significantly higher than normal control group (P < 0.05). There were no significant differences in Gissane's angle, Tibiocalcaneal angle, Length of calcaneus and Calcaneal facet height between patients with CAI and normal controls (P > 0.05). CONCLUSIONS: The osseous structures of STJ in CAI patients are different from normal people in morphology. Therefore, we should pay more attention to the changes of STJ anatomical parameters in the diagnosis and prevention of CAI. LEVEL OF EVIDENCE: Ⅲ.

Defining the Structures at Risk and an Anatomical Safe Zone for Percutaneous Antegrade Subtalar Joint Fixation With a Single Screw: A Cadaveric Study.

Percutaneous antegrade (anterior to posterior) fixation for subtalar joint (STJ) arthrodesis offers various intraoperative and biomechanical advantages. Currently, the entry point for percutaneous antegrade STJ screw fixation is not clearly described and variable. To our knowledge, there are no publications that evaluate anatomic structures at risk or define an anatomically safe entry point for this fixation. The aim of this investigation was to define an anatomically safe and reproducible entry point for percutaneous antegrade STJ arthrodesis fixation, while also describing anatomic structures at risk when undertaking this method of fixation. We hypothesized that percutaneous single screw antegrade STJ fixation would encroach upon named anatomic structures in more than one cadaveric specimen. Ten cadaver limbs were used in this investigation. A percutaneous guidewire was inserted 5 mm lateral to the tibialis anterior tendon. The midpoint of the talar neck served as the sagittal plane starting point, as seen on the lateral fluoroscopic view. A cannulated 6.5-mm headed screw was inserted antegrade through the STJ into the calcaneus. Each specimen was dissected to assess the distance from the screw to nearby anatomic structures and distance from the tibialis anterior tendon to named structures. Our hypothesis was found to be incorrect, as 0/10 screws invaded neurovascular or tendinous structures. The dorsalis pedis artery and deep peroneal nerve were on average 12.1 ± 2.79 mm and 12.2 ± 2.82 mm lateral to the screw, respectively. These findings are clinically relevant and ultimately allow us to define an anatomic safe starting point for percutaneous antegrade STJ single screw fixation.

Does medial calcaneal wedge improve static balance and load distribution in young adults with pronated foot?

BACKGROUND: Foot orthoses changing the momentum in the subtalar joint are often recommended, especially in activities loading the foot, to bring the pronated foot posture closer to neutral. OBJECTIVES: To examine the immediate effect of medial heel wedge on static balance and load distribution in patients with increased pronation in the foot. STUDY DESIGN: Experimental study design. METHODS: Forty people with right dominant lower extremity participated in the study. For static balance assessment, we assessed ellipse surface, sway length, x-y mean, AP index, and Romberg ratio on 1 foot and measured load distribution as right-left foot and fore-hind foot with and without wedge. RESULTS: There was a difference between the parameters of the ellipse surface and the Romberg ratio on the left side in the measurements performed with and without wedge for static balance on the left side ( P < 0.05) while there was no difference in the remaining values ( P > 0.05). In the load distribution, the change in the right anteroposterior foot was significant, increasing the load on the forefoot with the wedge ( P < 0.05) while we observed no difference in the left fore-hind foot load distribution and right-left foot load distribution ( P > 0.05). CONCLUSION: Our study showed that for static balance, medial wedge can improve balance on the left side by decreasing sway, and for load distribution, the medial wedge changed the load distribution from back to front on the right side. These small differences in young healthy individuals are a preliminary indication that further studies are needed.

Medializing Calcaneal Osteotomy for progressive collapsing foot deformity alters the three-dimensional subtalar joint alignment.

BACKGROUND: A medializing calcaneal osteotomy (MCO) is considered as one of the key inframalleolar osteotomies to correct progressive collapsing foot deformity (PCFD). While many studies were able to determine the post-operative hind- and midfoot alignment, alternations of the subtalar joint alignment remained obscured by superposition on plain radiography. Therefore, we aimed to assess the hind-, midfoot- and subtalar joint alignment pre- compared to post-operatively using 3D weightbearing CT (WBCT) imaging. METHODS: Seventeen patients with a mean age of 42 ± 17 years were retrospectively analyzed. Inclusion criteria consisted of PCFD deformity corrected by a medializing calcaneal osteotomy (MCO) as main procedure and imaged by WBCT before and after surgery. Exclusion criteria were patients who had concomitant calcaneal lengthening osteotomies, mid-/hindfoot fusions, hindfoot coalitions, and supramalleolar procedures. Image data were used to generate 3D models and compute the hindfoot (HA), midfoot (MA) - and subtalar joint (STJ) alignment in the coronal, sagittal and axial plane, as well as distance maps. RESULTS: Pre-operative measurements of the HA and MA improved significantly relative to their post-operative equivalents p < 0.05). The post-operative STJ alignment showed significant inversion (2.8° ± 1.7), abduction (1.5° ± 1.8), and dorsiflexion (2.3° ± 1.7) of the talus relative to the calcaneus (p < 0.05) compared to the pre-operative alignment. The displacement between the talus and calcaneus relative to the sinus tarsi increased significantly (0.6 mm±0.5; p < 0.05). CONCLUSION: This study detected significant changes in the sagittal, coronal, and axial plane alignment of the subtalar joint, which corresponded to a decompression of the sinus tarsi. These findings contribute to our clinical practice by demonstrating the magnitude of alteration in the subtalar joint alignment that can be expected after PCFD correction with MCO as main procedure.

Current Lack of Evidence on Treatment Strategies and Clinical Outcomes for Osteochondral Lesions of the Subtalar, Talonavicular, and Calcaneocuboid Joints: A Systematic Review.

OBJECTIVE: In contrast to osteochondral lesion (OCL) of the ankle, OCLs in other joints of the foot, such as subtalar joint, talonavicular joint, calcaneocuboid joint, and the midfoot, are rare conditions, but they can also lead to significant morbidity. The objective of this systematic review was to summarize the clinical evidence for the treatment of OCLs of the subtalar, talonavicular, calcaneocuboid, and the other midfoot joints. DESIGN: A systematic search of the MEDLINE, EMBASE, and Cochrane Library databases was performed in January 2021 based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines by 2 independent reviewers. Included studies were evaluated with regard to LOE (level of evidence) and QOE (quality of evidence). Variable reporting outcome data, clinical outcomes, and complications were evaluated. RESULTS: Seventeen studies with 21 patients were included, all of which were case reports (level 5) without any case series reporting greater than 3 patients. There were 5 patients with OCL in the subtalar joint, 15 patients in the talonavicular joint, and 1 patient in the calcaneocuboid joint. Thirteen case reports (4 subtalar joint, 8 talonavicular joint, and 1 calcaneocuboid joint) reported surgical treatment. Surgical procedures mainly included debridement, bone marrow stimulation, fixation, and bone grafting, through open or arthroscopy, all of which resulted in successful outcomes. Four case reports (1 subtalar joint, 3 talonavicular joint) reported successful conservative treatment. Other 13 case reports reported successful surgery after failed conservative treatment. No complications and reoperations were reported. CONCLUSIONS: The current systematic review revealed that there is no available evidence to ascertain clinical outcomes of both conservative and surgical treatments for cartilage lesions in the talonavicular joint, subtalar joint, and the midfoot joints, owing to the extreme paucity of literature. Both nonoperative and operative treatments can be considered, but no treatment strategies have been established.

Osteochondral Lesions of the Subtalar Joint: Clinical Outcomes in 11 Patients.

OBJECTIVE: The purpose of this retrospective case series was to evaluate clinical outcomes following both conservative treatment and arthroscopic bone marrow stimulation (BMS) for the management of symptomatic subtalar osteochondral lesions (OCLs). DESIGN: All symptomatic subtalar OCLs with a minimum of 12 months follow-up having undergone either a conservative management or arthroscopic procedure were included. Patient-reported outcomes were collected via questionnaires consisting of the Foot and Ankle Outcome Score (FAOS), Numeric Rating Scale (NRS) of pain in rest, during walking, during stair climbing, and during running. In addition, return to sports data, return to work data, reoperations, and complications were collected and assessed. In total, 11 patients across 2 academic institutions were included (3 males, 8 females). The median age was 43 years (interquartile range [IQR]: 32-53). RESULTS: All patients underwent conservative treatment first; in addition, 9 patients underwent subtalar arthroscopic debridement with or without BMS. The median follow-up time was 15 months (IQR: 14-100). In the surgically treated group, the median NRS scores were 2 (IQR: 1-3) during rest, 3 (IQR: 2-4) during walking, 4 (IQR: 4-5) during stair climbing, 5 (IQR: 4-5) during running and the median FAOS score at final follow-up was 74 (IQR: 65-83). In the conservatively treated patients, the median NRS scores were all 0 (IQR: 0-0) and the median FAOS scores were 90 (IQR: 85-94). In the group of surgical treated patients, 4 were able to return to the same level of sports, 2 returned to a lower level of sports. Both conservatively treated patients returned to the sport and the same level of prior participation. All patients except one in the surgical group returned to work. CONCLUSIONS: This retrospective case series demonstrated that a high number of patients converted to surgery after initial conservative treatment. In addition, debridement and BMS show good clinical outcomes for the management of symptomatic subtalar OCLs at short-term follow-up. No complications nor secondary surgical procedures were noted in the surgically treated group. The high rate of failure of conservative treatment suggests that surgical intervention for symptomatic subtalar OCLs can be the primary treatment strategy; however, further research is warranted in light of the small number of patients.

Shoe-Type Walking Assist Device with Controllable Subtalar Joint Alignment at Heel Contact.

In this study, we propose a shoe-type walking assist device that can control the inversion/eversion angle of the subtalar joint during heel contact, with the aim of improving the long-term quality of life of both elderly people and young healthy people. The proposed device enables the heel mechanism to rotate dynamically in the frontal plane to lead the subtalar joint alignment to the neutral position when the heel contacts the ground. The effectiveness of the proposed mechanism was demonstrated by comparing the amount of lateral thrust (lateral sway) during stepping movements with and without the mechanism assist in 5 healthy male subjects wearing the device.

Foot biomechanics in patients with advanced subtalar- and mid-tarsal joint osteoarthritis and poorly responding to conservative treatment.

BACKGROUND: A comprehensive insight into the effects of subtalar- and mid-tarsal joint osteoarthritis on lower limb's biomechanical characteristics during walking is lacking. Our goal was to assess joint kinematics and kinetics and compensatory mechanisms in patients with subtalar and mid-tarsal joint osteoarthritis. METHODS: Patients with symptomatic and radiographically confirmed osteoarthritis of the subtalar and mid-tarsal (n = 10) and an asymptomatic control group (n = 10) were compared. Foot joint kinematics and kinetics during the stance phase of walking were quantified using a four-segment foot model. RESULTS: During pre-swing phase, the tibio-talar range of motion in the sagittal plane of the patient group decreased significantly (P = 0.001), whereas the tarso-metatarsal joint range of motion in the sagittal plane was greater in the pre-swing phase (P = 0.003). The mid-tarsal joint showed lower transverse plane range of motion in the patient group during the loading response and pre-swing phase (P < 0.001 resp. P = 0.002). The patient group showed a lower Tibio-talar joint peak plantarflexion moment (P = 0.004), peak plantarflexion velocity (P < 0.001) and peak power generation in the sagittal plane (P < 0.001), and a lower mid-tarsal joint peak adduction and abduction velocity (P < 0.001 resp. P < 0.001) and peak power absorption (P < 0.001). CONCLUSIONS: These findings suggest that patients with subtalar and mid-tarsal joint osteoarthritis adopt a cautious walking strategy potentially dictated by pain, muscle weakness, kinesiophobia and stiffness. Since this poorly responding population faces surgical intervention on the short term, we recommend careful follow-up after fusion surgery since biomechanical outcome measures associated to this post-surgical stage is lacking.

Reconstruction of the interosseous talocalcaneal ligament using allograft for subtalar joint stabilization is effective.

PURPOSE: The aim of this study was to assess the biomechanical effects of subtalar ligament injury and reconstruction on stability of the subtalar joint in all three spatial planes. METHODS: Fifteen fresh frozen cadaveric legs were used, with transfixed tibiotalar joints to isolate motion to the subtalar joint. An arthrometer fixed to the lateral aspect of the calcaneus measured angular displacement in all three spatial planes on the inversion and eversion stress tests. Stress manoeuvres were tested with the intact joint, and then repeated after sequentially sectioning the inferior extensor retinaculum (IER), cervical ligament (CL), interosseous talocalcaneal ligament (ITCL), arthroscopic graft reconstruction of the ITCL, and sectioning of the calcaneo-fibular ligament (CFL). RESULTS: Sectioning the ITCL significantly increased angular displacement upon inversion and eversion in the coronal and sagittal planes. Reconstruction of the ITCL significantly improved angular stability against eversion in the axial and sagittal planes, and against inversion in the axial and coronal planes, at the zero time point after reconstruction. After sectioning the CFL, resistance to eversion decreased significantly in all three planes. CONCLUSION: Progressive injury of ligamentous stabilisers, particularly the ITCL, led to increasing angular displacement of the subtalar joint measured with the inversion and eversion stress tests, used in clinical practice. Reconstruction of the ITCL using tendon graft significantly stabilised the subtalar joint in the axial and sagittal planes against eversion and in the axial and coronal planes against inversion, immediately after surgery.