Lesser Metatarsophalangeal Instability: Diagnosis and Conservative Management of a Common Cause of Metatarsalgia

Nonoperative Treatment of Plantar Plate Tears

The plantar plate is a critical structure involved in stabilizing the metatarsophalangeal joint. Its disruption can not only be painful for the patient but also may lead to subsequent structural deformities. There are several conservative treatment modalities available to help mitigate symptoms including splinting, offloading, and intraarticular injections. That being said, once the pathology progresses to advanced stages, these treatments are not efficacious. Reported success with conservative treatment modalities is limited to case studies and series with a low level of clinical evidence. As such, this represents an area where further investigation is needed to evaluate the true efficacy of conservative treatment and to allow for development of a more standardized approach.

Effectiveness of the Fixtoe Device® in plantar pressure reduction: a preliminary study

Background

Metatarsalgia is a common foot condition. The metatarsophalangeal stabilizing taping technique described by Yu et al. has shown good clinical results as a provisional treatment in propulsive metatarsalgia. ³⁵ The Fixtoe Device®, a novel orthopedic device, intends to simulate stabilizing tape. However, to date, there is no evidence of its effectiveness. The aim of this study was to assess plantar pressure changes using the Fixtoe Device®, in comparison with the traditional method (stabilizing tape) in a young, healthy sample thorough a cross-sectional study.

Methods

Maximal pressure (Kpa) and pressure–time integral (Kpa/s) in the second metatarsal head were measured in twenty-four healthy volunteers. Registers were taken in four different conditions: barefoot, traditional stabilizing tape, Fixtoe Device® without metatarsal pad, and Fixtoe Device® with metatarsal pad.

Results

Mean second metatarsal head maximal pressure and mean pressure–time integral showed statistical difference among the four analyzed conditions (p < 0.0001 in both cases). The improvement in maximal pressure and pressure–time integral obtained in each intervention also showed significance (p < 0.0001 in both cases). Comparing the improvement of the Fixtoe Device® with and without metatarsal pad with that of tape condition showed a moderate to high and moderate effect size for both peak pressure and pressure–time integral reduction.

Conclusions

The Fixtoe Device® reduces median maximal pressure and median pressure–time integral under the second metatarsal head in healthy young individuals. The Fixtoe Device® shows higher effectiveness than the traditional second metatarsophalangeal joint stabilizing taping technique. To our knowledge, this is the first investigation proving the effectiveness of the recently developed Fixtoe Device® in terms of plantar pressure modification, which leads the way to its use in clinics.

Prospective Cohort Validation Study of a Novel Foot Offloading Device

Pressure offloading is often considered a crucial factor affecting healing after a foot injury. We have devised a novel foot offloading device (PopSole) which allows for immediate customization of the area where there is foot pain and allows for adjustable arch support and metatarsal pad height while maintaining patient stability. We hypothesize that pain and function outcomes will improve significantly after use of the device over a 1-month period. Ten participants with foot pain for longer than 6 months completed five validated outcome questionnaires during three visits (initial screening, at 2 weeks, and at 4 weeks). Devices were deflated in areas of pain specific for each patient. Validated patient reported outcomes measures showed significant improvement in pain and function from baseline to week two (r = 0.644, P < 0.05), (r = 0.43, P < 0.05), and (r = 0.552, P < 0.05), respectively, and the Foot & Ankle Ability Measure (FAAM) showed improved ability in activities of daily living (r = 0.58, P < 0.05) and sports (r = 0.69, P < 0.05). All 10 patients reported pain relief during at least one visit and/or an ability to return to standing-based activities that they previously were unable to do. PopSole rapidly improved pain and function, with sustained relief through 4 weeks. Current studies are in progress to assess long-term durability of the device and potential modifications to be made before future randomized studies to assess pressure and gait assessment, shear forces, and diabetic foot ulcer mitigation.