[Pathophysiology and etiology of the Charcot foot]. / Pathophysiologie und Ätiologie des Charcot-Fußes.

BACKGROUND: Despite extensive research, the pathophysiology of Charcot foot is still not fully understood. In the case of late diagnosis and insufficient therapy, severe deformity may occur. OBJECTIVES: Different theories on the pathophysiology of the Charcot foot are presented and discussed. MATERIALS AND METHODS: This article presents different theories on the pathophysiology of the Charcot foot and presents studies on the cellular, immunological, and bone metabolism level. RESULTS: One theory is based on repetitive microtraumas in the sensoric deficient foot which lead to development of Charcot foot. Another theory is based on pathologic neurovascular innervation leading to morphologic changes. Probably both mechanisms are responsible in combination as etiological factors inducing neuropathy CONCLUSION: A combination of mechanical, vascular, and biologic factors induce the neuropathic foot and result in severe deformity if diagnosis is too late.

[Differences in plantar loading between orthosis with and without lateral wedge in healthy subjects]. / Veränderungen der Fußdruckparameter mit und ohne laterale Schuhranderhöhung bei gesunden Probanden.

BACKGROUND: Insoles and foot orthotics change the distribution of the plantar pressure. No information exists concerning the effects of plantar pressure distribution and lateral wedge orthoses. The purpose of this study was to determine the effect of the lateral wedge on the plantar pressure distribution. METHODS: The GP Mobil Data system was used to evaluate the data mentioned above, using a 6 mm lateral wedge orthotic worn by 50 healthy volunteers (100 feet). Patient age was 18 to 61 years. The first measurement was performed with, the second without a 6 mm lateral wedge. 50 volunteers walked a standardised distance of 10 m and the results with and without the wedge were compared. For evaluation, the foot was divided in 6 different anatomic regions. Statistical analysis was performed with the t2 test using graph pad prism. RESULTS: The preliminary results revealed that the maximum peak pressure and intermediate pressure, contact time and force time integral decreased significantly at the medial middle- and forefoot plus the heel and increased significantly at the lateral middle- and forefoot using the lateral wedge. The maximum peak pressure under the great toe decreased by 22 % using a wedge, under the MTP I joint by 19 %, under the MTP II-III joints by 8 % and under the heel by 7 %. By contrast, maximum peak pressure increased under the area of MTP IV-V (+ 11.3 %) and under the lateral metatarsus (+ 15 %) when wearing a wedge. CONCLUSION: This study reveals the effects of a lateral wedge orthosis on the plantar pressure distribution of the foot. These relationships and the changing pattern may serve as a useful guide for the clinician. A full medical screen of the foot should be undertaken before laterally wedged foot orthotic devices are prescribed.

[The modified Lapidus arthrodesis]. / Die modifizierte Lapidus-Arthrodese.

For the correction of hallux valgus, as one of the most common deformities of the lower limbs, a modified Lapidus arthrodesis is applied at the base of the hallux. After using a lateral tissue technique with medial capsular reefing, a general arthrodesis of the tarsometatarsal 1 joint is carried out. An unstable hallux is the indication for a classic Lapidus arthrodesis. Before determination of the indication, an exact clinical x-ray examination should be made in the dorsoplanar position as well as laterally standing. Complications associated with the Lapidus arthrodesis are postoperative metatarsalgia and pseudoarthrosis. Advantages of this technique are, for example, a high correction potential and better healing, although the surgical technique and post-operative care are more time consuming than for other methods.