Distal Metatarsal Minimally Invasive Osteotomy (DMMO): Surgical technique, variants, indications, and treatment decision-tree

Minimally Invasive Forefoot Surgeries Using the Shannon Burr: A Comprehensive Review

Since the early 2000s, minimally invasive forefoot surgery (MIS), particularly hallux valgus correction, has significantly advanced with the introduction of the Shannon burr. However, despite numerous relevant studies being published, no comprehensive review articles have summarized MIS for various forefoot conditions. Therefore, in this comprehensive review, we examined the relevant studies about the application of MIS (excluding arthroscopy and endoscopy) for various forefoot conditions. Additionally, we discuss the essential considerations for achieving favorable surgical outcomes and preventing complications associated with each technique. We analyzed the characteristics of each surgical procedure and identified areas for future focus. Effective surgical treatment not only requires MIS, but also the appropriate selection of patients based on suitable indications and executing procedures within the surgeon's capabilities. We hope that this review will help readers to enhance their expertise in this field.

Radiographic Evidence of Sufficient Transverse Plane Alignment after Weil Osteotomy without Screw Fixation

Weil osteotomy is a proven procedure to restore the harmonic distal parabola of the forefoot. In addition to the proximal displacement of the head in the sagittal plane, a displacement in the transverse plane may be necessary, with the refixation of the displaced metatarsal head historically performed by screw fixation. We aimed to determine the radiological differences among 136 feet of 127 patients with 256 Weil osteotomies retrospectively enrolled and divided into groups with (n = 182) and without (n = 74) screw fixation. Demographic data, radiographic union, pre- and postoperative metatarsal angles, and differences in the dorsoplantar view were evaluated. The mean follow-up period was 3.6 months. The mean preoperative metatarsophalangeal angle was 9.24°, and the mean postoperative angle was 12.99°. The restoration of the transversal alignment plane was equally successful in both groups, with a mean extent of angle correction of 10.58°. No nonunions of the osteotomized metatarsals were observed. The radiographic comparisons revealed no significant difference between the groups (p > 0.05). However, visibility of the joint space of the metatarsophalangeal joint was achieved significantly more often in the group without screw fixation (p < 0.05). In the absence of bony malunion and the satisfactory restoration of a harmonious parabola of the forefoot, apparently there does not appear to be a necessity for regular screw fixation after Weil osteotomy based on the available data from the present study.

Risks of injury in distal metatarsal minimally invasive osteotomy when comparing standard and modified techniques: A cadaveric study

BACKGROUND

The objectives of the study were to evaluate the structures at risk in distal metatarsal mini-invasive osteotomy (DMMO) and to compare standard and intraosseous approaches.

METHODS

DMMO was performed on the second and fourth metatarsals of 11 fresh-frozen cadaveric specimens. The standard technique was performed in 11 metatarsals. It was then compared to a modified intraosseous technique that entails starting inside the bone in 11 other metatarsals. The cadavers were dissected to identify unintentional injury to soft tissue structures.

RESULTS

In the standard group the most injured structures were the metatarsal joint capsules (MJC) (27%), extensor digitorum longus (EDL) (18%), and extensor digitorum brevis (EDB) (9%). The modified intraosseous group injured the EDL (27%), not the MJC (0%) and the EDB (0%). Distances between osteotomies and the dorsal metatarsal head articular surface (DMHAS) were 6.08 ± 3.99 mm in the standard and 9.92 ± 3.42 mm in the modified (p = 0.02).

CONCLUSION

The DMMO techniques most frequently injured the EDL. Intra-articular positioning of the osteotomy was more observed in the standard. Overall, it appears the modified method could be an alternative to the standard DMMO.

CLINICAL RELEVANCE

The modified minimally invasive DMMO has a comparable rate of potential iatrogenic injuries. This intraosseous procedure may present as an option when planning surgery to the lesser metatarsals.

LEVEL OF EVIDENCE

Level III. Comparative Cadaveric Study.