Current Insights On Treating Second MPJ Dysfunction
If patients with second metatarsophalangeal joint (MPJ) dysfunction experience a delayed diagnosis or misdiagnosis, the condition can become progressively worse and lead to complications. Accordingly, this author discusses issues with second MPJ surgery, the emerging role of plantar plate repair and a suture and button technique that may prove to be beneficial.
The subtle subluxation of the lesser metatarsophalangeal joint (MPJ) is a chronic, slowly progressive, inflammatory condition referred to as predislocation syndrome.1 When it comes to this chronic pain in the plantar forefoot, physicians commonly misdiagnose it as a neuroma, stress fracture or tendonitis, among other things. Patients often describe the pain as a dull, aching sensation beneath the base of the second digit, just distal to the metatarsal head.
Often, patients describe the sense that they are walking on something like a grape. For some patients, it may feel like their sock is bunched up beneath the ball of their foot. Typically, there is no recall of frank injury but often one can identify a change in activity level from a detailed interview. A person may have just begun to exercise to lose weight or recently started a walking program. Perhaps the patient has changed jobs with the new job requiring more weightbearing activity or increased weightbearing on firm or hard surfaces as in industrial work or the like. Perhaps the patient has simply gained much weight over time.
Most importantly, when the physician misses, misdiagnoses or neglects second MPJ dysfunction, it will progressively worsen with repetitive cycling of the joint. The inflammation will persist, the plantar plate and collateral ligaments will wear, and subtle deviation of the digit in the transverse and/or sagittal plane will occur.
While it is understood that the plantar plate is the strongest fibrous structure supporting the MPJs, the collateral ligaments also play a fundamental role in stabilization of the digit. Often, a combination of sagittal plane and transverse plane deformity develops. Although the natural history of progression is well understood, no one can predict just how quickly this deformity will occur. This may be accelerated by the abnormal mechanics associated with hallux abducto valgus, a long second metatarsal or the injudicious use of steroids physicians deliver into and around the MPJ.
It is predictable that with misdiagnosis, physicians often inappropriately select injection therapy and this can promptly bring the deformity to progressive subluxation and even dislocation at the MPJ level. This occurs all too often. Indeed, it is important have a very high index of suspicion for this chronic inflammatory condition. Early identification and prompt stabilization of the joint will definitively slow the progression of deformity if not halt it altogether. Simple things like the metatarsal sling pad can achieve very good success.
When A Prodromal Syndrome Exists With Recurring Pain
Speaking from my personal experience, I have numerous patients in my relatively young practice (13 years) who have never required surgery as a result of this early intervention. Unfortunately, the people who do best are the ones who already have deformity.
Why do I say unfortunately? When people come in reporting symptoms without any evidence of subluxation, a prodromal syndrome or “stage 0” condition may exist. This stage is associated with an insidious onset of pain, which becomes progressively worse and interferes with a patient’s sense of well-being. At this time, the patient usually has not altered his or her activity level, which contributes to an ongoing and increasing inflammatory reaction as repetitive cycling of the joint continues without support or stabilization.