Emerging Insights On Surgical Correction Of Laterally Deviated Toes
Therefore, based on the available literature, the “ideal” relative metatarsal length pattern appears to be when the first and second metatarsals are equal in length, and a gentle taper exists between the remaining metatarsals (1=2>3>4>5).
One should clearly understand that proper metatarsal relationships involve both the relative length of the metatarsals and the sagittal plane relationship. This should consist of each metatarsal being oriented parallel to one another on the weightbearing surface during the stance and propulsive phases of the gait cycle.2,7,12 One can best determine the relative sagittal plane relationship between the metatarsals on a medial oblique radiograph.7
Pertinent Insights On The Weil Distal Oblique Metatarsal Osteotomy
The Weil distal oblique metatarsal osteotomy has received much attention regarding central metatarsal abnormalities.16-27 Surgeons have even applied this technique to the hand for metacarpal deformities.28 The Weil distal oblique metatarsal osteotomy involves minimal soft tissue dissection, is easy to perform, allows precise placement of the plantar capital fragment, can involve multiple modifications, is inherently stable in design requiring a minimal amount of internal fixation, and allows for immediate guarded weightbearing.7,16,17
In this procedure, the surgeon would perform a dorsal linear incision extending from the distal one-third of the lesser metatarsal to the base of the proximal interphalangeal joint of the associated digit. When performing surgery on adjacent metatarsals, one would place the incision over the intermetatarsal space instead.
Regardless of placement, deepen the incision directly through the skin, superficial fascia and adipose tissue to the level of the capsule and periosteum overlying the lesser MPJ. Several approaches to the lesser MPJ are possible and include: (1) splitting the natural junction between the extensor digitorum longus and brevis when there is no transverse plane toe deviation; (2) direct medial incision when there is lateral toe deviation; and (3) direct lateral incision when there is medial toe deviation.7,16,17
Regardless of approach, after you incise the extensor tendon complex, reflect the capsule and periosteum using a surgical scalpel and periosteal elevator in order to expose the dorsal, medial and lateral aspects of the lesser metatarsal head and neck. Begin the osteotomy at a level 2 mm below the dorsal articular cartilage of the lesser metatarsal head. Angle the osteotomy proximally in such a manner as to extend it to the junction of the distal and middle third of the metatarsal. This junction is just proximal to the plantar metaphyseal-diaphyseal junction and is termed the “axilla” or “cul-de-sac” of the lesser metatarsal.7,16,17 This angle approximates a 10- to 15-degree plantar angle in comparison with the longitudinal axis of the metatarsal, which in turn is plantar declinated in relation to the weightbearing surface of the foot.7,16,17
The surgeon would perform a “pure” Weil osteotomy by completing the osteotomy through the plantar diaphysis, creating two separate osseous segments. The plantar capital fragment will readily migrate proximally and, interestingly, almost always “settles” at the desired level of shortening. However, one should verify this with intraoperative image intensification to properly determine the appropriate degree of shortening to balance the metatarsal parabola as I previously described.
If one performs more than 3 mm of shortening for any of the central metatarsals, remove a small “slice” bone from the plantar capital fragment since it has a larger bone mass than the remaining metatarsal shaft.16,19 Then hold the plantar capital fragment in full apposition with either a small “scoop type” elevator or with the index finger from your non-dominant hand. Provide dorsally directed pressure at the proximal extent of the osteotomy and fixate this with one or two small diameter non-lag screws and/or threaded Kirschner wires. One can then gently resect any redundant dorsal osseous prominence with a rongeur to a normal anatomical configuration.