Non-uniform displacement within the Achilles tendon during passive ankle joint motion.

PURPOSE: An initial step in the understanding of Achilles tendon dynamics is to investigate the effects of passive motion, thereby minimising muscle activation and reducing internal joint forces. Internal tendon dynamics during passive ankle joint motion have direct implications for clinical rehabilitation protocols after Achilles tendon surgery. The aim of this study was to test the hypothesis that tendon tissue displacement is different in different layers of the Achilles tendon during controlled passive ankle joint movements. METHODS: Ultrasound imaging was conducted on the right Achilles tendon of nine healthy recreationally active males. Standardised isokinetic passive dorsi-plantar-flexion movements were performed with a total range of motion of 35°. The tendon was divided into superficial, central and deep layers in the resulting B-mode ultrasound images viewed in the sagittal plane. A block-matching speckle tracking algorithm was applied post-process, with kernels for the measurement of displacement placed in each of the layers. RESULTS: The mean (SD) displacement of the Achilles tendon during passive dorsiflexion was 8.4 (1.9) mm in the superficial layer, 9.4 (1.9) mm in the central portion and 10.4 (2.1) mm in the deep layer, respectively. In all cases, the movement of the deep layer of the tendon was greater than that of the superficial one (P < 0.01). CONCLUSIONS: These results, achieved in vivo with ultrasonographic speckle tracking, indicated complex dynamic differences in different layers of the Achilles tendon, which could have implications for the understanding of healing processes of tendon pathologies and also of normal tendon function.

Surgical treatment of hallux valgus and forefoot deformities in Sweden: a population-based study.

BACKGROUND: Although surgical correction for hallux valgus and other toe deformities is one of the most common procedures in foot surgery, its incidence in the general population is not well-known. MATERIALS AND METHODS: The study population comprised patients living in Sweden of a varied age group and both sexes who underwent forefoot surgery. We identified all inpatient cases from 1997 to 2000 and all ambulatory cases in 2000 registered in the National Swedish Patient Register (NSPR). Further, clinical data for the surgical treatment of hallux valgus deformity were extracted from medical records in patients treated in a geographically defined region (Stockholm). RESULTS: In total, 6956 patients with surgically treated forefoot deformities were identified from the adult population, equivalent to a cumulative incidence of 0.8 procedures per 1000 inhabitants for the whole analyzed group. There were regional variations and significant sex differences. The age distribution in both sexes was characterized by a peak in the fifth decade. Forefoot surgery was statistically more frequently performed in private clinics than in public hospitals (p < 0.001). Hallux valgus surgery was by far the most common procedure regarding forefoot surgery. CONCLUSION: The prevalence of forefoot- and hallux valgus surgery was not evenly distributed in the six major regions in Sweden. It is more common in urban than in rural regions. Furthermore, forefoot surgery is performed more frequently in private clinics than in community hospitals despite common financial sources.