Ankle arthrodesis through Meary's anterolateral access

Objective: This study aimed to assess indications for surgical treatment, position of the ankle, time and rate of fusion after arthrodesis; to ascertain whether the technique provides fusion rates similar to those described in the published literature; and to quantify patients’ improvement according to the AOFA and VAS scores, and patients’ satisfaction using a Likert scale. Methods: This is a clinical study with a cohort of 18 patients (9 women and 9 men) with a mean age of 49.10 years, conducted from 2006 and 2016. Results: Post-traumatic arthrosis (88.88%), rheumatoid arthritis (5.56%), and Charcot-Marie-Tooth disease (5.56%) motivated the surgeries. Six ankles fused in an equinus position, and 12 of them in a neutral position. Five ankles fused in valgus angulation, and 13 in a neutral position. Five ankles fused in external rotation, 2 in internal rotation and 11 in a neutral position. In the postoperative period, American Orthopaedic Foot and Ankle Society (AOFAS) and visual analogue scale (VAS) scores showed an improvement of 31.6 points and 5.1 points, respectively. Regarding the Likert scale, 2 patients reported being very satisfied, 14 satisfied, and 2 partially satisfied. Conclusion: Fusion in a 100% of cases and patients’ overall satisfaction have led to the conclusion that this treatment method is appropriate to attain ankle fusion, with results similar to those found in the medical literature. Level of Evidence IV; Therapeutic Studies; Case Series.

Abnormal Bone Morphology in Charcot-Marie-Tooth Disease

Background: Although long suspected, it has yet to be shown whether the foot and ankle deformities of Charcot-Marie-Tooth disease (CMT) are generally associated with abnormalities in osseous shape. Computed tomography (CT) was used to quantify morphologic differences of the calcaneus, talus, and navicular in CMT compared with healthy controls. Methods: Weightbearing CT scans of 21 patients (27 feet) with CMT were compared to those of 20 healthy controls. Calcaneal measurements included radius of curvature, sagittal posterior tuberosity-posterior facet angle, and tuberosity coronal rotation. Talar measurements included axial and sagittal body-neck declination angle, and coronal talar head rotation. Surface-mesh model analysis of the hindfoot was performed comparing the average of the CMT cohort to the controls using a CT analysis software (Disior Bonelogic 2.0). Means were compared with a t test ( P < .05). Results: CMT patients had significantly less talar sagittal declination vs controls (17.8 vs 25.1 degrees; P < .05). Similarly, CMT patients had less talar head coronal rotation vs controls (30.8 vs 42.5 degrees; P < .001). The calcaneal radius of curvature in CMT patients was significantly smaller than controls (822.8 vs 2143.5 mm; P < .05). CMT sagittal posterior tuberosity–posterior facet angle was also significantly different from that of controls (60.3 vs 67.9 degrees respectively; P < .001). Surface-mesh model analysis demonstrated the largest differences in morphology at the navicular tuberosity, medial talar head, sustentaculum tali, and anterior process of the calcaneus. Conclusion: This is the first study to quantify the morphologic differences in hindfoot osteology seen in CMT patients. Patients identified with osseous changes of the calcaneus, especially a smaller axial radius of curvature, may benefit from a 3-dimensional osteotomy for correction.

A mutation associated with Charcot-Marie-Tooth disease enhances the formation of stable dynamin 2 complexes in cells

Mutations in dynamin 2 (DNM2) have been associated with two distinct motor disorders, Charcot-Marie-Tooth neuropathies (CMT) and centronuclear myopathy (CNM). The majority of these mutations are clustered in the pleckstrin homology domain (PHD) which engage in intramolecular interactions that suppress dynamin self-assembly and GTPase activation. CNM mutations in the PHD interferes with these intramolecular interactions, thereby blocking the formation of the auto-inhibited state. CMT mutations are located primarily on the opposite surface of the PHD, which is specialized for lipid PIP2 binding. It has been speculated that the distinct locations and interactions of residues mutated in CMT and CNM explain why each set of mutations cause either one disease or the other, despite their close proximity within the PHD sequence. We show that at least one CMT-causing mutant, lacking residues 555DEE557 (∆DEE), displays this inability to undergo auto-inhibition as observed in CNM-linked mutants. This ∆DEE deletion mutant induces the formation of abnormally large cytoplasmic inclusions similar to those observed for CNM-linked mutant R369W. We also found substantially reduced migration from the membrane of the ∆DEE deletion mutant. These findings call into question the molecular mechanism currently believed to underlie the absence of pathogenic overlap between DNM2-dependent CMT and CNM.