Ninety-Degree Chevron Osteotomy for Correction of Hallux Valgus Deformity: Clinical Data and Finite Element Analysis

Abstract

Hallux valgus is a very common foot disorder, with its prevalence estimated at 33% in adult shoe-wearing populations. Conservative management is the initial treatment of choice for this condition, but surgery is sometimes needed. The 600 angle Chevron osteotomy is an accepted method for correction of mild to moderate hallux valgus in adults less than 60 years old. A modified 900 angle Chevron osteotomy has also been described; this modified technique can confer some advantages compared to the 600 angle method, and reported results are good. In the current work we present clinical data from a cohort of fifty-one female patients who had surgery for sixty-two hallux valgus deformities. In addition, in order to get a better physical insight and study the mechanical stresses along the two osteotomies, Finite Element Analysis (FEA) was also conducted. FEA indicated enhanced mechanical bonding with the modified 900 Chevron osteotomy, because the compressive stresses that keep the two bone parts together are stronger, and the shearing stresses that tend to slide the two bone parts apart are weaker, compared to the typical 600 technique. Follow-up data on our patient cohort show good or excellent long-term clinical results with the modified 900 angle technique. These results are consistent with the FEA-based hypothesis that a 900 Chevron osteotomy confers certain mechanical advantages compared to the typical 600 procedure.

Comparision of the Stress Distribution Between High-Heeled and Flat Shoes on The First Metatarsal Bone

“…In addition to the given [18], the forces of muscles was included to investigate the mechanical response on the bone. There is no information about the some changing forces while information about the percentage of the BW and the changing angle may be accessed in literature [10,15,16,22]. Such the unknown forces is calculated using a geometric approach as seen in Figure. 2.…”

“…Contrary to what is stated in [23], flexor hallucis longus (C) and flexor hallucis brevis (D) having a certain angle to A, not perpendicular to it. The first metatarsal bone having a 35° between ground in push-off stage when wearing flat shoes [15]. A is the perpendicular to the MTP joint head.…”

“…The plantar pressure distribution that is occurring under the foot could be determined by the transducer [12], dynamometer [11] or the various pressure sensors which is placed on the sole of the foot. One of the easiest ways to analyze the stress and the pressure distribution is Finite Element Analysis (FEA) [13][14][15][16]. The walking takes place in the three stages [17].…”

“…The plantar and dorsiflexion angles of the first metatarsal bone change depending on the height of the heel [24]. Due to the increased angle of the first metatarsal bone with the ground, all forces increase compared to the flat shoes [10,15]. It is important to know the force distribution that is acting on the first metatarsal bone before and after the operation of foot bone deformities such as hallux valgus.…”

Computational Models of the Foot and Ankle for Pathomechanics and Clinical Applications: A Review

“…Chevron osteotomy was investigated using a 2D first metatarsal model and compared the compressive and shearing stress of the bone under a surgical protocol of 60-and 90°incision angles. 41 The modified 90°Chevron osteotomy could produce better union loading conditions. A load-to-failure scenario was simulated using 3D metatarsal models that were drilled with holes according to the surgical protocol of hallux valgus correction.…”