Introduction. The prevalence of symptomatic osteoarthritis (OA) in the knee is 11–11% compared to 3.4–4.4% in the ankle. In addition to this, 70% of ankle arthritis is post-traumatic while the vast majority of knee arthritis is primary OA. Several reports have previously implicated biochemical differences in extracellular matrix composition between these joint cartilages; however, it is unknown whether there is an inherent difference in their transcriptome and how this might affect their respective functionality under load, inflammatory environment etc. Therefore, we have analysed the transcriptome of ankle and knee cartilage chondrocytes to determine whether this could account for the lower prevalence and altered aetiology of ankle OA. Methods. Human full-depth articular cartilage was taken from the talar domes (n=5) and the femoral condyles (n=5) following surgical amputation. RNA was extracted and next generation sequencing (NGS) performed using the NextSeq®500 system. Statistical analysis was performed to identify differentially regulated genes (p adj < 0.05). Data was analysed using Integrated Pathway Analysis software and genes of interest validated by quantitative PCR. Results. 809 genes were differentially expressed in this NGS study: 781 genes were significantly up-regulated and 27 significantly down-regulated in ankle cartilage with respect to knee. Preliminary analysis has identified several pathways which are differentially regulated including ‘inflammation mediated by cytokines’, ‘glutamate receptor pathway, ‘heterotrimeric-G-protein signalling pathways’, ‘WNT signalling’ and ‘integrin signalling’. Discussion. This is the first report identifying genes that are differentially expressed in ankle cartilage compared to the knee. Validation is currently being performed to ascertain the importance of these gene changes and correlation with their protein expression in the different joints. An understanding of the inherent biological differences in the cartilage between these two joints will provide invaluable insight into why the ankle is relatively spared from primary OA and the majority of ankle arthritis occurs following trauma

Introduction. Fibula shortening with an intact anterior tibiofibular ligament (ATFL) and medial ligament instability causes lateral translation of the talus. Our hypothesis was that the interaction of the AITFL tubercle of the fibular with the tibial incisura would propagate lateral translation due to the size differential. Aim. To assess what degree of shortening of the fibular would cause the lateral translation of the talus. Methodology. Twelve cadaveric ankle specimens were dissected removing all soft tissue except for ligaments. They were fixed on a specially-designed platform within an augmented ankle cage allowing tibial fixation and free movement of the talus. The fibula was progressively shortened in 5mm increments until complete ankle dislocation. The medial clear space was measured with each increment of shortening. Results. The larger AITFL tubercle interaction with the smaller tibial incisura caused a significant increase in lateral translation of the talus. This occurred in most ankles between 5–10mm of fibular shortening. The medial clear space widened following 5mm of shortening in 5 specimens (mean=2.0725, SD=±2.5338). All 12 specimens experienced widening by 10mm fibula shortening (Mean=7.2133mm, SD=±2.2061). All specimens reached complete dislocation by 35mm fibula shortening. Results of ANOVA analysis found the data statistically significant (p<0.0001). Conclusion. This study shows that shortening of the fibula causes a significant lateral translation of the talus provided the ATFL remains intact. Furthermore, the interaction of the fibula notch with the ATFL tubercle of the tibia appears to cause a disproportionate widening of the medial clear space due to its differential in size. Knowledge of the extent of fibula shortening can guide further intervention when presented with a patient experiencing medial clear space widening following treatment of an ankle fracture

Introduction. The anatomy of the first metatarsophalangeal (MTP) joint and, in particular, the metatarsosesamoid articulation remains poorly understood. The movements of the sesamoids in relation to the metatarsal plays a key role in the function of the first MTP joint. Although the disorders affecting the sesamoids are described well, the movements of the metatarsosesamoid joints and the pathomechanics of these joints have not been described. We have performed a cadaver study detailing and quantifying the three dimensional movements occurring at these joints. Methods. Fresh frozen cadaveric specimens without evidence of forefoot deformity were dissected to assess the articulating surfaces throughout a normal range of motion. The dissections were digitally reconstructed in positions ranging from 10 degrees of dorsiflexion to 60 degrees of plantarflexion using a MicroScribe, enabling quantitative analyses in a virtual 3D environment. Results. The sesamoids demonstrated excursion both in the sagittal and coronal plane. The tibial sesamoid had a mean saggital excursion of 14.2 mm; the mean excursion of the fibular sesamoid was 8.7 mm. The mean coronal excursion of the tibial sesamoid was 2.8 mm while that of the fibular sesamoid was 3.2 mm. We also describe the mean saggital and coronal excursion of the sesamoids during smaller, incremental motions of the MTP joint. Conclusion. There appears to be differential tracking of the hallucal sesamoids. The tibial sesamoid has comparatively increased longitudinal excursion whilst the fibular sesamoid has comparatively greater lateral excursion. Clinical relevance. The greater excursion of the tibial sesamoid could explain the higher incidence of pathology in this bone. The differential excursion of the sesamoids is also a factor that should be considered in the design and mechanics of an effective hallux MTP joint arthroplasty

Introduction. Bone tumours of the foot are rare, representing 3–6% of all bone tumours. Of these 15–25% are thought to be malignant. Obtaining clear surgical margins remains an important factor in improving outcome from tumours. However, the anatomical complexity of the foot can lead to an inadequate resection, particularly if the operating surgeon is attempting to preserve function. The aim of this paper is to identify the clinical course of patients suffering from malignant bone tumours of the foot. Method. A prospective tumour registry over a 30 yr period was used to identify patients with a malignant bone tumour of the foot. Patient demographics along with the site of primary malignancy, region of the foot involved and clinical management were recorded. Results. 70 patients with a malignant foot tumour were identified. 25(35%) were chondrosarcomas, 20 Ewings Sarcoma, 10 Osteosarcoma and 15 were metastatic lesions. Of those diagnosed with a primary bone tumour, 8(14.5%) were referred following a “whoops” procedure. The median length of symptoms prior to diagnosis was 52 weeks. The most common regions affected were the 1. st. Ray (31%) and Calcaneus (22%). The mainstay of treatment involved either Ray or Below Knee Amputation in 70% of cases. 11 patients developed either local recurrence or metastatic disease. Conclusion. We present the largest single centre review of malignant bone tumours affecting the foot. Our series confirms that patients often have to suffer with protracted symptoms prior to the establishment of the correct diagnosis. The variety of differential diagnoses may explain the long delay in diagnosis. Worryingly, 14.5% of the primary bone malignancies in our series underwent a “whoops” procedure. This highlights further that physicians need to maintain a high index of suspicion when treating a patient with foot symptoms, even when the symptoms may be protracted

Neuropathic changes in the foot are common with a prevalence of approximately 1%. The diagnosis of neuropathic arthropathy is often delayed in diabetic patients with harmful consequences including amputation. The appropriate diagnosis and treatment can avoid an extensive programme of treatment with significant morbidity for the patient, high costs and delayed surgery. The pathogenesis of a Charcot foot involves repetitive micro-trauma in a foot with impaired sensation and neurovascular changes caused by pathological innervation of the blood vessels. In most cases, changes are due to a combination of both pathophysiological factors. The Charcot foot is triggered by a combination of mechanical, vascular and biological factors which can lead to late diagnosis and incorrect treatment and eventually to destruction of the foot.

This review aims to raise awareness of the diagnosis of the Charcot foot (diabetic neuropathic osteoarthropathy and the differential diagnosis, erysipelas, peripheral arterial occlusive disease) and describe the ways in which the diagnosis may be made. The clinical diagnostic pathways based on different classifications are presented.

Cite this article: Bone Joint J 2016;98-B:1155–9.

The precise localisation of osteoarthritic changes is crucial for selective surgical treatment. Single photon-emission CT-CT (SPECT-CT) combines both morphological and biological information. We hypothesised that SPECT-CT increased the intra- and interobserver reliability to localise increased uptake compared with traditional evaluation of CT and bone scanning together. We evaluated 20 consecutive patients with pain of uncertain origin in the foot and ankle by radiography and SPECT-CT, available as fused SPECT-CT, and by separate bone scanning and CT. Five observers assessed the presence or absence of arthritis. The images were blinded and randomly ordered. They were evaluated twice at an interval of six weeks. Kappa and multirater kappa values were calculated.

The mean intraobserver reliability for SPECT-CT was excellent (κ = 0.86; 95% CI 0.81 to 0.88) and significantly higher than that for CT and bone scanning together. SPECT-CT had significantly higher interobserver agreement, especially when evaluating the naviculocuneiform and tarsometatarsal joints.

SPECT-CT is useful in localising active arthritis especially in areas where the number and configuration of joints are complex.

We undertook a retrospective review of 24 arthroscopic procedures in patients with symptomatic ossicles around the malleoli of the ankle. Most of the patients had a history of injury and localised tenderness in the area coinciding with the radiological findings. Contrast-enhanced three-dimensional fast-spoiled gradient-echo MRI was performed and the results compared with the arthroscopic findings. An enhanced signal surrounding soft tissue corresponding to synovial inflammation and impingement was found in 20 patients (83%). The arthroscopic findings correlated well with those of our MRI technique and the sensitivity was estimated to be 91%. At a mean follow-up of 30.5 months (20 to 86) the mean American Orthopaedic Foot and Ankle Society score improved from 74.5 to 93 points (p < 0.001). Overall, the rate of patient satisfaction was 88%.

Our results indicate that symptomatic ossicles of the malleoli respond well to arthroscopic treatment.