Proximal Metatarsal Osteotomies: A Comparative Geometric Analysis Conducted on Sawbone Models

Abstract

We evaluated the change in position of the first metatarsal head using a three-dimensional digitizer on sawbone models. Crescentic, closing wedge, oblique shaft (Ludloff 8 degrees and 16 degrees), reverse oblique shaft (Mau 8 degrees and 16 degrees), rotational "Z" (Scarf), and proximal chevron osteotomies were performed and secured using 3-mm screws. The 16 degrees Ludloff provided the most lateral shift (9.5 mm) and angular correction (14.5 degrees) but also produced the most elevation (1.4 mm) and shortening (2.9 mm). The 8 degrees Ludloff provided lateral and angular corrections similar to those of the crescentic and closing wedge osteotomies with less elevation and shortening. Because the displacement osteotomies (Scarf, proximal chevron) provided less angular correction, the same lateral displacement, and less shortening than the basilar angular osteotomies, based upon this model they can be more reliably used for a patient with a mild to moderate deformity, a short first metatarsal, or an intermediate deformity with a large distal metatarsal articular angle. These results can serve as recommendations for selecting the optimal osteotomy with which to correct a deformation.

Outcomes after Scarf Osteotomy for Treatment of Adult Hallux Valgus Deformity

“…Complications, intraoperative and postoperative, have been reported at variable incidences, including troughing of the metatarsal, fracture, delayed union, rotational malunion, recurrence of deformity, and infection [4,12,14,20,21]. The nature of the osteotomy is more technically challenging, has a higher surgical learning curve, and requires meticulous attention to the threedimensional changes [17]. Smith et al [21] reported a 6% perioperative complication rate from their early experience to create awareness for those beginning to master the scarf osteotomy.…”

Angular correction and complications of proximal first metatarsal osteotomies for hallux valgus deformity

“…However, it illustrates the need for further prospective comparative studies. Basically, proximal osteotomies are recommended for the treatment of moderate to severe deformities [3,[5][6][7]. The studies included in this meta-analysis also contained patients who suffered from mild to moderate hallux valgus deformity.…”

“…Mild deformity has less than 15°intermetatarsal 1-2 angle (IMA), moderate deformity has 15-20°IMA and severe deformity has more than 20°IMA [6]. Mathematical analysis revealed that distal metatarsal osteotomies (DMO) provide less corrective power than proximal metatarsal osteotomies (PMO).…”

“…The complications include shortening and dorsiflexion malunion leading to first ray insufficiency. Due to this fact, its use is limited in spite of its theoretically superior corrective power compared to DMO [3,6,7].…”

Biomechanical analysis of two fixation methods for proximal chevron osteotomy of the first metatarsal

“…A multitude of biomechanical studies have evaluated the initial stability of various metatarsal osteotomies, not only to determine which osteotomies permit early MTP joint exercises, but also to identify those which may allow early postoperative weight bearing [2,13,14,[18][19][20][21][22].…”