How To Address Key Biomechanical Issues With Second MPJ Injuries
Q: What is your protocol for conservative treatment of suspected injury to the plantar plate of the second MPJ?
A: All three panelists cite the use of icing. Dr. Kirby suggests icing 20 minutes twice a day directly plantar to the second MPJ. He says this can significantly reduce plantar edema in the MPJ, which in turn can help reduce the compression forces on the plantar plate during weightbearing activities.
Dr. Kirby also cites plantarflexion taping of the digit to relieve the tensile forces on the plantar plate. This allows the injury to heal faster and leads to reduced pain with weightbearing, according to Dr. Kirby. Dr. Bouché concurs. He also suggests using digital spacers if there is any transverse plane component to the deformity. Dr. Bouché also recommends using a metatarsal binder or corset to stabilize the medial column by decreasing the first and second intermetatarsal angle.
In order to allow normal healing, Dr. Kirby says it is essential to use modified over-the-counter foot orthoses or prescription foot orthoses that are designed to reduce the ground reaction forces plantar to the second MPJ.
For Dr. Bouché, orthotic treatment options also include OTC or custom orthoses to control excessive pronation, forefoot extensions with the second metatarsal cutout and/or a metatarsal “cookie,” and a rigid rocker-soled shoe to offload the forefoot. Depending on the stage of the problem, Dr. Bouché says NSAIDs or a walking boot can be helpful in the acute/subacute stages. Dr. Kirby also recommends four to six weeks of a boot walker brace or a below-knee immobilization cast, which may be necessary to rest the injured plantar plate and to permit healing if other methods have not prevailed.
Conservative treatment for offloading of the second MPJ must be the first and foremost objective, emphasizes Dr. Clough. He says one can only accomplish that by restoring normal motion of the first MPJ and properly engaging the windlass mechanism of the foot structure.
If a functional hallux limitus is not properly engaging the windlass mechanism, he says the first metatarsal will not displace into the ground as part of dorsiflexion of the first MPJ and therefore, the first metatarsal will not accept adequate weightbearing into propulsion. Dr. Clough explains that when the foot goes into propulsion with a very unstable foot structure and an unstable first ray, the second MPJ will overload since the anatomy of the foot dictates that the second metatarsal will not be able to displace dorsally under weightbearing forces as well as the first metatarsal is capable of doing.
Dr. Clough notes the Cluffy Wedge® is often a very effective addition to a shoe insole or OTC device before one considers custom orthotic therapy. As he explains, the wedge will offload the second MPJ by increasing dorsiflexion of the first MPJ and improving first metatarsal plantarflexion. After offloading the second MPJ, he says physical therapeutic modalities may be of some benefit. Dr. Clough warns that under no circumstances should one inject corticosteroids since it will further weaken the soft tissues and aggravate the condition.