Defining reference values for the normal tibiofibular syndesmosis in adults using weight-bearing CT.

AIMS: Cone beam CT allows cross-sectional imaging of the tibiofibular syndesmosis while the patient bears weight. This may facilitate more accurate and reliable investigation of injuries to, and reconstruction of, the syndesmosis but normal ranges of measurements are required first. The purpose of this study was to establish: 1) the normal reference measurements of the syndesmosis; 2) if side-to-side variations exist in syndesmotic anatomy; 3) if age affects syndesmotic anatomy; and 4) if the syndesmotic anatomy differs between male and female patients in weight-bearing cone beam CT views. PATIENTS AND METHODS: A retrospective analysis was undertaken of 50 male and 50 female patients (200 feet) aged 18 years or more, who underwent bilateral, simultaneous imaging of their lower legs while standing in an upright, weight-bearing position in a pedCAT machine between June 2013 and July 2017. At the time of imaging, the mean age of male patients was 47.1 years (18 to 72) and the mean age of female patients was 57.8 years (18 to 83). We employed a previously described technique to obtain six lengths and one angle, as well as calculating three further measurements, to provide information on the relationship between the fibula and tibia with respect to translation and rotation. RESULTS: The upper limit of lateral translation in un-injured patients was 5.27 mm, so values higher than this may be indicative of syndesmotic injury. Anteroposterior translation lay within the ranges 0.31 mm to 2.59 mm, and -1.48 mm to 3.44 mm, respectively. There was no difference between right and left legs. Increasing age was associated with a reduction in lateral translation. The fibulae of men were significantly more laterally translated but data were inconsistent for rotation and anteroposterior translation. CONCLUSION: We have established normal ranges for measurements in cross-sectional syndesmotic anatomy during weight-bearing and also established that no differences exist between right and left legs in patients without syndesmotic injury. Age and gender do, however, affect the anatomy of the syndesmosis, which should be taken into account at time of assessment. Cite this article: Bone Joint J 2019;101-B:348-352.

The relationship of MRI findings and clinical features in symptomatic and asymptomatic os naviculare.

AIM: To investigate the relationship between magnetic resonance imaging (MRI) findings and clinical features in patients with os naviculare. MATERIALS AND METHODS: All patients with a foot or ankle MRI study showing an os naviculare were identified from a specialist orthopaedic hospital between 2014 and 2017. A total of 110 patients with 133 os naviculare were included. The MRI features were recorded, as well as the presence or absence of medial foot pain and/or tenderness over the navicular tuberosity. Fisher's exact test was used for categorical data and unpaired t-tests for continuous data. Specificity and sensitivity were calculated for MRI features. RESULTS: There were 80 female and 30 male patients with a mean age of 46±1.7 years at time of MRI (range 11-90.6 years). There was a significant correlation between os naviculare oedema (p=0.008) and navicular tuberosity oedema (p=0.001) with a history of medial foot pain. There were significant associations between mean age (p=0.003), type of os naviculare (p=0.004), os naviculare oedema (p<0.001), navicular tuberosity oedema (p=0.001), and soft tissue oedema (p=0.01) with examination findings of tenderness over the navicular tubercle. Oedema of the os naviculare, navicular tuberosity, or soft tissues were found to have a high specificity but low sensitivity for medial foot pain and tenderness. CONCLUSION: When present, certain MRI findings indicate that an os naviculare is likely to be a cause of patient symptoms, but when absent they do not exclude the possibility of it causing symptoms.

Prevalence of isolated gastrocnemius tightness in patients with foot and ankle pathology: a population-based study.

Aims: Gastrocnemius tightness predisposes to musculoskeletal pathology and may require surgical treatment. However, it is not clear what proportion of patients with foot and ankle pathology have clinically significant gastrocnemius tightness. The aim of this study was to compare the prevalence and degree of gastrocnemius tightness in a control group of patients with a group of patients with foot and ankle pathology. Patients and Methods: This prospective, case-matched, observational study compared gastrocnemius tightness, as assessed by the lunge test, in a control group and a group with foot and ankle pathology. Gastrocnemius tightness was calculated as the difference in dorsiflexion of the ankle with the knee extended and flexed. Results: A total of 291 controls were paired with 97 patients with foot and ankle pathology (FAP). The mean gastrocnemius tightness was 6.0° (sd 3.5) in controls and 8.0° (sd 5.7) in the FAP group (p < 0.001). Subgroup analysis showed a mean gastrocnemius tightness of 10.3° (sd 6.0) in patients with forefoot pathology versus 6.9° (sd 5.3) in patients with other pathology (p = 0.008). A total of 12 patients (37.5%) with forefoot pathology had gastrocnemius tightness of > two standard deviations of the control group (> 13°). Conclusion: Gastrocnemius tightness of > 13° may be considered abnormal. Most patients with foot and ankle pathology do not have abnormal degrees of gastrocnemius tightness compared with controls, but it is present in over a third of patients with forefoot pathology. Cite this article: Bone Joint J 2018;100-B:945-52.

Evaluation of the 1st metatarso-sesamoid joint using standing CT - The Stanmore classification.

BACKGROUND: Little is understood about the role that relative sesamoid displacement and chondral wear have on outcome after hallux valgus (HV) surgery. All existing methods to evaluate relative sesamoid displacement have limitations and furthermore, there have been no radiographic studies evaluating metatarso-sesamoid joint wear. Standing CT scan circumvents many of the existing problems in evaluation of relative sesamoid displacement, and also enables the first radiographic study assessing metatarso-sesamoid joint wear. METHODS: Fifty feet (in 43 patients) with symptomatic HV (Group A) were compared with a control group of 50 feet (50 patients) (Group B). All images were standardised to enable reproducible measurements. The hallux valgus angle, Intermetatarsal angle, sesamoid rotation angle, sesamoid position and metatarso-sesamoid joint space were measured in all patients. RESULTS: The intra and inter-observer reliability correlation showed that the standing CT assessment of sesamoid position (1.000), rotation (0.991) and metatarso-sesamoid joint space (0.960) were highly reproducible. There was a highly significant difference (p<0.0001) in sesamoid position, sesamoid rotation and metatarso-sesamoid joint space between Group A and Group B. CONCLUSIONS: Standing CT has been shown to be a reproducible and accurate method of assessing the relative sesamoid displacement and metatarso-sesamoid joint space narrowing. The results have been used to propose a novel standing CT based classification of hallucal sesamoids, considering the degree of displacement and wear. This classification may ultimately facilitate research to provide new insight into the effect relative sesamoid displacement and chondral wear have on outcomes from hallux valgus surgery.

Stress fractures of the foot and ankle.

Stress fractures occur as a result of microscopic injuries sustained when bone is subjected to repeated submaximal stresses. Overtime, with repeated cycles of loading, accumulation of such injuries can lead to macro-structural failure and frank fracture. There are numerous stress fractures about the foot and ankle of which a trauma and orthopaedic surgeon should be aware. These include: metatarsal, tibia, calcaneus, navicular, fibula, talus, medial malleolus, sesamoid, cuneiform and cuboid. Awareness of these fractures is important as the diagnosis is frequently missed and appropriate treatment delayed. Late identification can be associated with protracted pain and disability, and may predispose to non-union and therefore necessitate operative intervention. This article outlines the epidemiology and risk factors, aetiology, presentation and management of the range of stress fractures in the foot and ankle.

The value of Weight-Bearing CT scan in the evaluation of subtalar distraction bone block arthrodesis: Case report.

Subtalar distraction arthrodesis is performed in certain situations where there is loss of subtalar height, reduced talar declination and evidence of anterior tibiotalar impingement. Standard evaluation includes the assessment of the lateral talocalcaneal angle, calcaneal pitch, talocalcaneal height and talar declination angle on a weight bearing lateral radiograph. We present a case of erosive valgus subtalar osteoarthritis with subtalar collapse managed with a subtalar distraction arthrodesis. A weight bearing CT (WB-CT) scan was used in the assessment. The value of WB-CT for this indication is discussed, along with a discussion on surgical technique, complications and future directions.

Talar Neck Fracture after United Tibiotalar Fusion.

Tibiotalar arthrodesis is a well-established treatment for tibiotalar arthritis, for example, in younger high demand patients. Talar neck fractures are less common though well-recognised sequelae of foot ankle trauma. Here we present the clinical case of a 69-year-old male who presented to our institution with a nonunion of a talar neck fracture, having undergone a left tibiotalar fusion 24 years previously. To the authors' knowledge, this injury has only been described once previously in the literature. However, the original case described a fracture sustained in the very early postoperative period following tibiotalar fusion, postulated to be secondary to postimmobilisation osteopaenia or stress risers from metalwork. The aetiology in this case is likely due to axial compression transmitted to the talar neck via the calcaneus. The predisposing factors for nonunion are discussed, highlighting the importance of vigilance for this injury in any patient with concomitant tibiotalar fusion and foot trauma. The management of this patient is discussed.

Lisfranc injuries.

Lisfranc injuries are commonly asked about in FRCS Orthopaedic trauma vivas. The term "Lisfranc injury" strictly refers to an injury where one or more of the metatarsals are displaced from the tarsus. The term is more commonly used to describe an injury to the midfoot centred on the 2nd tarsometatarsal joint. The injury is named after Jacques Lisfranc de St. Martin (1790-1847), a French surgeon and gynaecologist who first described the injury in 1815. 'Lisfranc injury' encompasses a broad spectrum of injuries, which can be purely ligamentous or involve the osseous and articular structures. They are often difficult to diagnose and treat, but if not detected and appropriately managed they can cause long-term disability. This review outlines the anatomy, epidemiology, classification, investigation and current evidence on management of this injury.

Recurrent multifocal diabetic myonecrosis: a cause of severe extremity pain in a diabetic patient.

We detail the unusual occurrence of successive episodes of diabetic myonecrosis in both lower and upper limbs in a young woman with diabetic end organ dysfunction. We highlight the importance of recognising this as a differential diagnosis for acute limb pain in diabetic patients and advocate conservative measures for successful treatment and return to function.

Local recurrence of osteosarcoma after 17 years.

The recurrence of osteosarcoma is rare. Local recurrence occurs in 4-10% of patients following effective treatment. So far, recurrences as late as 15 years have been reported in the literature. We report a unique case of local recurrence of intramedullary osteosarcoma 17 years from initial diagnosis and treatment. Regular long-term follow-up of patients with this diagnosis is crucial to ensure early detection and treatment of potential recurrences.