Plantar Plate Reconstruction for Stage IV Plantar Plate Tear Using Flexor Tendon Tenodesis

Category: Lesser Toes Introduction/Purpose: Outcomes of the surgical treatment of dislocated lesser toes have improved significantly over the past few years due to the development of techniques to repair plantar plate tears through a dorsal incision. However, treatment of stage 4 tears with no reparable plantar plate can be challenging. The current treatment involves flexor to extensor tendon transfer, requiring multiple incisions and surgical time. An alternative approach is presented, using the same modern techniques of plantar plate repair, but reconstructing the plantar plate using a flexor tendon tenodesis to the plantar base of the proximal phalanx. Methods: Four fresh frozen cadaver foot and ankle specimens were used to determine the stability of this new technique. A simulated Lachman’s test was performed on the 2nd, 3 rd, and 4th metatarsophalangeal joints utilizing a force measurement instrument with displacement control on specimens with an intact plantar plate, an excised plantar plate, and following a flexor tenodesis reconstruction. Results: The intact plantar plate force was 9.0+2.6kN for 2 mm displacement, and following excision of the plantar plate, the force reduced to 1.3+0.4kN. The flexor tenodesis reconstruction improved the force to 6.0+1.9kN. Conclusion: Plantar plate reconstruction with a flexor tenodesis to the proximal phalanx resulted in stability equal to 53% of the intact plantar plate, for the shear displacements between 2 to 6 mm. This procedure may be an alternative treatment option in patients with Stage 4 irreparable plantar plate tears

Evaluating the Subtalar Joint in Tibiotalocalcaneal Nail

Category: Hindfoot Introduction/Purpose: In tibiotalocalcaneal nails for arthrodesis, the path of the nail through the subtalar joint has not been well documented. Ideally, the defect caused by reaming and the nail does not pass through the joint surface so that the amount of bony contact between the talus and calcaneus is maintained in order to optimize fusion. Our hypothesis is that the TTC nail does not destroy a significant amount contact area between the talus and calcaneus. However, using larger diameter nails (which are inherently stronger) will have more of an effect on the contact surface. Methods: Five cadaveric below the knee specimens were obtained. The ankle was disarticulated on each specimen. Subsequently, a guidepin was drilled from the central dome of the talus down to the calcaneus. The 11 mm reamer was then passed over the guidepin through the calcaneus to simulate retrograde reaming of a TTC nail. Then, the subtalar joint was dissected open and the articular surface was documented in comparison with the area that was reamed out. Measurements were then made, using software that calculated two dimensional surface area to determine the percentage of actual subtalar joint area that was reamed out. The mean percentage of articular area that was removed with the reamer was then calculated. Results: Among the five specimens, in the calcaneus, the mean total articular area was 599mm2±113 and the mean drilled articular area was 21mm2±16. The percentage of the calcaneal articular surface that was removed with the reamer was 3.4%±1.9. In the talus, the mean total articular area was 782mm2±130 and the mean drilled articular area was 39mm2±18. The percentage of the talar articular surface that was removed with the reamer was 5.0%±2.3. Additionally, an 11 mm reamer makes a circular surface area of 95mm2, and the statistics above indicate that a significant portion of the reamed area is nonarticular, within the calcaneal sulcus or the talar sulcus. Conclusion: In a tibiotalocalcaneal nail the subtalar joint is typically incompletely visualized, however this anatomic study demonstrates that the 11 mm reamer eliminates about 3.4% of the calcaneal articular surface and about 5% of the talar articular surface. Therefore, the majority of the articular surface is left intact, which is ideal in optimizing arthrodesis outcomes. Furthermore, this study could extrapolate the effects of a larger nail on the availability of joint surface. It could also be used to argue for cartilage stripping of the affected joint surfaces in arthrodesis preparation, because the majority of the articular surface is, in fact, left intact