Second metatarsal osteotomies for metatarsalgia: A robotic cadaveric study of the effect of osteotomy plane and metatarsal shortening on plantar pressure

Abstract

Symptom relief of recalcitrant metatarsalgia can be achieved through surgical shortening of the affected metatarsal, thus decreasing plantar pressure. Theoretically an oblique metatarsal osteotomy can be oriented distal to proximal (DP) or proximal to distal (PD). We characterized the relationship between the amount of second metatarsal shortening, osteotomy plane, and plantar pressure. We hypothesized that the PD osteotomy is more effective in reducing metatarsal peak pressure and pressure time integral. We performed eight DP and eight PD second metatarsal osteotomies on eight pairs of cadaveric feet. A custom designed robotic gait simulator (RGS) generated dynamic in vitro simulations of gait. Second metatarsals were incrementally shortened, with three trials for each length. We calculated regression lines for peak pressure and pressure time integral vs. metatarsal shortening. Shortening the second metatarsal using either osteotomy significantly affected the metatarsal peak pressure and pressure time integral (first and third metatarsal increased, p < 0.01 and <0.05; second metatarsal decreased, p < 0.01). Changes in peak pressure (p ¼ 0.0019) and pressure time integral (p ¼ 0.0046) were more sensitive to second metatarsal shortening with the PD osteotomy than the DP osteotomy. The PD osteotomy plane reduces plantar pressure more effectively than the DP osteotomy plane. Keywords: second metatarsal; plantar pressure; metatarsalgia; lesser metatarsal osteotomies; gait simulation Metatarsalgia is defined as pain, often during weight bearing, of the plantar aspect of the foot under and related to the lesser metatarsal heads. Primary metatarsalgia is associated with biomechanical insufficiencies, and secondary metatarsalgia is associated with systemic conditions. 1 Initially, metatarsalgia is managed with rest, stretching exercises, cushioning, plantar callosity shaving, and anti-inflammatory medications, but data confirming their effectiveness is limited.2 If symptoms persist, surgery is employed to correct the alignment of the metatarsals and/or muscle/ligament balance. Numerous surgical treatments are used, each with its benefits and complications.2-6 Surgical treatment redistributes pressure under the metatarsal heads 7 by either dorsally displacing the head or by shortening the length of the metatarsal. 3 The amount of shortening is determined by the surgeon's experience considering the preoperative length of the metatarsals. 4,8 In this study, we compared the effects of two different osteotomy planes and the overall amount of second metatarsal shortening on plantar pressure. Insight into the relationship between osteotomy plane, metatarsal shortening, and plantar pressure contributes to a more effective treatment of metatarsalgia by providing the surgeon with greater knowledge of biomechanical principles that can be used to make intraoperative osteotomy decisions.The oblique distal to proximal (DP) sliding osteotomy and the oblique proximal to distal (PD) sliding osteotomy are designed to reduce sec...

Comparison of Proximal and Distal Oblique Second Metatarsal Osteotomies with Varying Achilles Tendon Tension

“…Our findings are generally in agreement with those in a recent cadaver study by Trask et al 13 , who used a complex, realistic gait simulator that included Achilles tendon load and other muscles. Their study focused on the influence of the osteotomy plane and magnitude of shortening on plantar pressures, and showed proximal osteotomy to have greater efficacy than distal osteotomy.…”

“…Cadaveric modeling of modified distal oblique osteotomies by Lau et al 8 did not show that these modifications affected plantar pressure, although the study did not include loading of any muscles. Trask et al examined the effect of the obliquity of proximal diaphyseal osteotomies with regard to off-loading of the second metatarsal head and found that osteotomies directed from dorsal proximal to plantar distal were more effective than the reverse 13 . Primary limitations of some previous investigations include not using a stable fixation (e.g., screw) method for the osteotomy and the exclusion of muscle forces such as those via the Achilles tendon.…”

Foot–ankle simulators: A tool to advance biomechanical understanding of a complex anatomical structure

“…In addition, other surgical techniques have been studied using in vitro gait simulations; Bayomy et al 63 studied the effect of the first metatarsophalangeal joint arthrodesis on the plantar pressure distribution, while Van Bergen et al 39 and Anderson et al 64 focused on talar dome resurfacing and its influence on joint loading conditions. Finally, Trask et al 65 investigated the effect of osteotomy of the second metatarsal on plantar pressure peak, whereas Meardon et al 66 studied the effect of orthotics on the ground reaction forces and on the bone strain of the metatarsal bone. In all of these studies, the use of gait simulations allowed to explore the effect of each specific intervention, without any harmful effects on patients.…”

Design and validation of a foot–ankle dynamic simulator with a 6-degree-of-freedom parallel mechanism

“…The simulation of the stance phase was 2.7 s but the reproduced GRF was smaller than the actual value. [32][33][34][35][36][37][38] Besides that, the earliest passive simulator was designed in 2003 and there was no further development in the follow-up. 39,40 Another passive simulator, UMS, was designed in 2009 and applied to investigate the biomechanical behaviors of a diabetic foot.…”