Sonography of the superomedial part of the spring ligament complex of the foot: a study of cadavers and asymptomatic volunteers.
ABSTRACT To evaluate the ability of high-resolution sonography for assessing the thickness and echogenicity of the superomedial part of the normal spring ligament in the foot in cadavers and asymptomatic volunteers.
The superomedial part of the normal spring ligament of four cadaveric feet was imaged with a high-resolution linear array transducer. Upon localization, the ligament was injected with 0.1% methylene blue with sonographic guidance. A posteromedial approach was used to dissect the feet immediately following injection to confirm accurate identification of the ligament. The bilateral ligaments in 40 asymptomatic adult volunteers were subsequently imaged.
Surgical dissection confirmed the accurate injection of methylene blue into all four cadaveric ligaments. The superomedial part of the normal spring ligament was identified bilaterally in all of the 40 asymptomatic volunteers, with a mean thickness of 3 mm in longitudinal short axes. The ligament was echogenic relative to surrounding fat, and it was thinner in women. Differences in ligament measurements with respect to age, sex, side (left vs. right) and foot dominance were not significant. The volunteers' height, weight and body mass index had a weakly positive correlation with ligament thickness.
High-resolution ultrasound can be used to identify and measure the thickness of the superomedial part of the normal spring ligament. The provided baseline measurements for the normal ligament could prove valuable when assessing the abnormal ligament.
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Conference Paper: Perturbation bounds for structured robust stability[Show abstract] [Hide abstract]
ABSTRACT: Structured robust stability involves large (but bounded) perturbations in certain loops of a multivariate system. That is, structured robust stability entails stability in the face of large, structured perturbations. The authors study the persistence under small, unstructured parametric perturbations of the robust stability (structured or unstructured) of a system. They derive parameter perturbation bounds which when repeated, ensure the robust stability of the perturbed modelsDecision and Control, 1988., Proceedings of the 27th IEEE Conference on; 01/1989
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ABSTRACT: We present nine cases of acquired flat foot deformity (AFFD) in adults caused by isolated spring ligament insufficiency. We present the clinical sign that allows differentiation of this diagnosis from posterior tibialis tendon (PTT) dysfunction namely the ability to single leg tiptoe, but with persistent forefoot abduction and heel valgus. In addition we illustrate the unique radiological features which allow confirmation of the diagnosis. Only a solitary previous case report has documented this alternative aetiology of AFFD; in that case, diagnosis was made intra-operatively. Six patients have been managed with orthoses. Three patients underwent surgery; one patient who presented early had isolated repair of the spring ligament complex. The remaining two required a calcaneal osteotomy and flexor digitorum longus transfer as for a PTT reconstruction. We propose that early diagnosis (with ultrasound confirmation) and management of this condition would offer a better prognosis and allow less interventional surgery.Foot and Ankle Surgery 02/2008; 14(2):89-95.
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ABSTRACT: OBJECTIVE: To evaluate the association of posterior tibial tendon dysfunction and lesions of diverse ankle structures diagnosed at MRI with radiologic signs of flat foot. MATERIAL AND METHODS: We retrospectively compared 29 patients that had posterior tibial tendon dysfunction (all 29 studied with MRI and 21 also studied with weight-bearing plain-film X-rays) with a control group of 28 patients randomly selected from among all patients who underwent MRI and weight-bearing plain-film X-rays for other ankle problems. In the MRI studies, we analyzed whether a calcaneal spur, talar beak, plantar fasciitis, calcaneal bone edema, Achilles' tendinopathy, spring ligament injury, tarsal sinus disease, and tarsal coalition were present. In the weight-bearing plain-film X-rays, we analyzed the angle of Costa-Bertani and radiologic signs of flat foot. To analyze the differences between groups, we used Fisher's exact test for the MRI findings and for the presence of flat foot and analysis of variance for the angle of Costa-Bertani. RESULTS: Calcaneal spurs, talar beaks, tarsal sinus disease, and spring ligament injury were significantly more common in the group with posterior tibial tendon dysfunction (P<.05). Radiologic signs of flat foot and anomalous values for the angle of Costa-Bertani were also significantly more common in the group with posterior tibial tendon dysfunction (P<.001). CONCLUSION: We corroborate the association between posterior tibial tendon dysfunction and lesions to the structures analyzed and radiologic signs of flat foot. Knowledge of this association can be useful in reaching an accurate diagnosis.Radiología 04/2012;