Current Concepts In Plantar Plate Repair
The following week, the lead author and his Fellow, Jason Glover, DPM, tried different combined Weil osteotomy/plantar plate repairs on cadavers and came up with a reproducible technique. They started performing the procedure for patients with the most unstable, painful metatarsalgia and closely followed the patients and their results. The lead author presented the first series of cases at the International Federation of Foot and Ankle Surgeons the following fall in Brazil with very encouraging early results showing high function and diminished incidence of floating toe.
Why Shorten The Metatarsal?
Metatarsalgia is one of the most common problems we see as foot and ankle specialists. Typically, the position and length of the second metatarsal (and occasionally the third) have created a biomechanical imbalance in the forefoot, causing pain and subsequent injury to the surrounding soft tissue structures, particularly the plantar plate. During the propulsive phase of gait, an elongated metatarsal will be overloaded with every step. Over time, that overload will cause attrition to the plantar plate and surrounding soft tissue structures, leading to pain, swelling, deviation of the joint, crossover toe deformity, hammertoe and ultimately dislocation.
Radiographically, this manifests as a subtle difference in the length of the second metatarsal in comparison to the contralateral foot (for unilateral pathology) or in comparison to the expected normal second metatarsal protrusion distance (for bilateral pathology). In our patients with unilateral plantar plate tears, the side with the plantar plate pathology had a second metatarsal protrusion distance of 4.4 ± 1.0 mm, which is 0.6 mm longer than the contralateral/non-pathological side (3.8 ± 1.0 mm).8
It is necessary to correct the underlying deformity by shortening the metatarsal. Without metatarsal shortening, soft tissue corrections will fail over time. Not correcting the metatarsal in this situation is much like addressing a posterior tendon dysfunction solely by repairing the tendon without changing the structural component with appropriate calcaneal osteotomies, arthroereisis or fusion procedures.
Why Repair The Plantar Plate?
The earliest description of the plantar plate can be credited to Cruveilhier, who described the plantar plate as a static structure that served to “protect” the lower portion of the lesser MPJ while increasing joint space area.9 More recently, authors have theorized the plantar plate to serve as both a static and dynamic structure having attachments to the deep transverse intermetatarsal ligament, the lateral collateral ligaments and the plantar fascia.10
The plantar plate is one of the main stabilizers of the lesser metatarsophalangeal joint. In concert with the collateral ligament complex, sagittal and transverse plane deformity (including dislocation) are resistant at the level of the MPJ. Sectioning of the plantar plate will decrease the amount of force necessary to dislocate the MPJ by 30 percent.11 Sectioning of the collateral ligaments will decrease the amount of force to dislocate the MPJ by 45 percent. Sectioning of both structures will decrease the amount of force needed to dislocate the MPJ by 79 percent.
It stands to reason, therefore, that pathology of the plantar plate needs repair in order to restore stability to the lesser MPJ. This concept is similar to that of a Brostrom procedure for lateral ankle stabilization. When the primary stabilizing structure of a joint undergoes repair, the joint becomes more stable.