1) One should perform a small dorsal incision for release of the MPJ contracture and a metatarsal osteotomy (if necessary) first.
2) Complete a partial tear in a transverse fashion and resect 2 to 3 mm of redundant plantar plate once you have pinned the toe and MPJ with a wire.
3) Utilize a pants-over-vest primary repair with a non-absorbable suture and a UR-6 needle to allow for easier suture passing.
4) If one encounters a complete tear from the proximal phalanx, consider a small suture anchor in the proximal phalanx for added fixation.
5) Maintain the use of a wire in a plantarflexed position for at least four weeks postoperatively during healing.
6) Careful anatomic dissection and retraction, as well as eversion of skin edges during closure, will help prevent a painful plantar scar.
Correcting The Crossover Toe With Direct Plantar Plate Repair
Lesser metatarsophalangeal joint (MPJ) pathology is one of the most common conditions affecting the forefoot. Most commonly located at the second MPJ, progressive subluxation and dislocation of the phalangeal base on the metatarsal head primarily results from the disruption of the plantar plate, which often begins as predislocation syndrome.1 Painful dislocation of the toe in the dorsal plane, and less commonly in the medial or lateral planes, causes pain with ambulation and shoegear. Anatomic studies have demonstrated the importance of the plantar plate in stabilization of the MPJ in the sagittal plane.2,3
The physician diagnoses a plantar plate rupture primarily by clinical examination. By employing a vertical stress test (Lachman), one can evaluate the integrity of the MPJ plantar plate structure in order to determine the dorsal-plantar stability.4 When the clinician applies a dorsal-plantar force of the proximal phalanx on a stabilized metatarsal head, patients with a positive vertical stress exam will exhibit pain and subluxation or dislocation at the MPJ. A positive vertical stress exam indicates damage to the plantar plate. Digital deformities, such as a hammertoe or clawtoe contracture, may also be present in conjunction with a plantar plate tear.
It is important to examine the patient in both a seated and standing position. The digital deformity may often change position during weightbearing or assume a position of maximum pain. Additionally, concomitant hallux valgus may be present with an overlapping second toe, also creating instability in the transverse plane.
Standard weightbearing radiographs are useful to determine the metatarsal parabola and the amount of subluxation that may be present in the lesser MPJs. Advanced imaging, such as a magnetic resonance imaging (MRI) or ultrasound, may be advantageous to the diagnosis of a plantar plate tear. Klein and colleagues recently identified 100 percent specificity and a 73.9 percent sensitivity when correlating intraoperative findings to preoperative MRI evaluations for a plantar plate tear.5 In another study by Klein and colleagues, a longitudinal ultrasound image had a positive predictive value and sensitivity of 91.1 percent while transverse plane ultrasound only had an accuracy of 38 percent in correctly identifying a plantar plate tear.6
Conservative treatment of MPJ instability with a plantar plate tear focuses on palliating the dorsally dislocated toe and plantar pain. One can accomplish this with various modalities, such as crossover taping, strapping, splints or customized orthotics with an offloading metatarsal pad.
When conservative treatment fails, surgery is often warranted for pain relief and deformity correction. Tendon transfers, metatarsal osteotomies, hammertoe correction and plantar plate repairs are all reportedly successful. Researchers have discussed combining a dorsal approach to plantar plate repair with a shortening metatarsal osteotomy but this can be technically challenging and often complicated with the inability to fully visualize and repair a plantar plate tear.7,8
A Step-By-Step Guide To Surgical Technique
To provide increased visualization of the plantar plate and allow a direct primary plantar plate repair, we present our plantar-based approach to lesser MPJ instability repair.