Study Examines First MPJ Arthrodesis Failure And Revisions

A recent study examines the most common reasons for failure of first metatarsophalangeal joint (MPJ) arthrodesis and the most effective revision procedures.

The multicenter study, published in Orthopaedics & Traumatology: Surgery & Research, retrospectively analyzed 135 patients who had revision for first MPJ arthrodesis. The mean time to revision was 4.6 years and the mean follow-up was 20.5 months following revision. The researchers noted revisions were due to hardware discomfort in 54 percent of patients, due to nonunion in 14 percent and due to malunion in 8 percent.

The study adds that for patients with nonunion, removing the hardware led to better outcomes than a second arthrodesis. Osteotomy for patients with malunion healed successfully, while for patients with first MPJ osteoarthritis, secondary arthrodesis or arthroplasty facilitated good outcomes, according to the study.

First MPJ arthrodesis procedures for severe hallux valgus deformities or end-stage hallux rigidus are “the most successful procedure I perform on a weekly basis,” says Jeffrey McAlister, DPM, FACFAS. Typically, he sees a revision in one or two out of 100 patients, usually within the first two or three years out from the index procedure.    

H. John Visser, DPM, FACFAS, notes having “little trouble overall” with first MPJ arthrodesis. However, he has experienced nonunion when surgeons use cross screws for osteosynthesis. Since converting to lag screw and plating constructs, he has seen few problems. He will place those patients in a controlled ankle motion (CAM) boot with crutches and permit heel weightbearing for three weeks. If good radiographic consolidation is present, he will allow full weightbearing for the remaining three weeks.

Malunion occurs when surgeons violate the 20/20 rule, according to Dr. Visser, the Director of the SSM Depaul Hospital Foot and Ankle Surgery Residency in St. Louis. As he explains, this rule means failure of the hallux being abducted and dorsiflexed 20 degrees in the transverse and sagittal planes. Dr. Visser has found revisions for malunion occur early usually due to shoe wear issues and he can usually remedy malunion with a corrective osteotomy.

As Dr. McAlister says, the primary cause of a painful first MPJ arthrodesis is malposition and/or a disregard of patient expectations. He notes a first MPJ arthrodesis can heal with various types of fixation with a low nonunion rate with high patient satisfaction. A patient will request a revision when the position of the great toe is either still in valgus, or the hallux is malpositioned in the sagittal plane, according to Dr. McAlister, who practices at Arcadia Orthopedics and Sports Medicine in Phoenix. Despite arthrodesis being a highly reproducible procedure, he says there are technical details that surgeons often overlook.

To prevent a malposition and provide optimal hallux orientation, Dr. McAlister recommends utilizing a cadaver lab to take a step back and perform the procedure with the great toe in slight dorsiflexion or plantarflexion. He says this allows the surgeon to place the foot in a weightbearing attitude and visualize the repercussions of the malposition, and will also provide an appreciation of the prominent hardware.

Is Beaming Better Than Plantar Plating For Charcot? 

By Brian McCurdy, Managing Editor

Beaming for Charcot is sturdier than plantar plating, as the success of beaming is less dependent on bone quality, notes a recent study.

The cadaver study, published in the Journal of Foot and Ankle Surgery, concerned five paired bilateral feet with Charcot. Each right foot had cannulated titanium beams and each left foot had plates. As the study notes, the beamed and plated feet had statistically similar stiffness and mean strain on the plantar surfaces of the first metatarsal. However, the authors note the beamed specimens withstood a mean load to failure of 234 N in comparison to 140 N for plated specimens, a statistically significant difference.

With intramedullary beaming, the surgeon inserts a screw or bolt in the medullary canal, which bridges the damaged joint or bone in Charcot foot, according to Lawrence Fallat, DPM, FACFAS. As he says, beaming across multiple joints disperses the axial load without the need for a plate or screws, which prevents possible stress risers in cortical bone.

Damian Hilbert, DPM, adds that another advantage to cannulated beaming is that the guide wire achieves temporary reduction as the surgeon advances it across each joint prior to inserting the beam. He notes one can also perform beaming through a less invasive approach with minimal periosteal stripping, which lowers infection risk in a population with impaired wound healing, and preserves periosteal blood supply. He and Dr. Fallat, the Podiatry Residency Program Director at Beaumont Hospital in Wayne, Mich., note beaming is appropriate for patients with a high body mass index (BMI), questionable adherence or severe Charcot deformity.

Guido LaPorta, DPM, FACFAS, notes surgeons can perform beaming with a minimally invasive approach. However, surgeons should be aware that beam retrieval and removal is much more difficult and that a beam is also a load-sharing device, says Dr. LaPorta, the Chief of Foot and Ankle Surgery at Geisinger Community Medical Center in Scranton, Pa.

While plantar plating also allows spanning of the diseased bone, Drs. Fallat and Hilbert say plating requires much more extensive dissection and surgical time in comparison to beaming. They cite another disadvantage to plating: the plantar surface of the medial column is irregular, leading to a difficult application if the plate is not properly contoured or if the bone is not resected appropriately. Dr. Fallat and Dr. Hilbert, a second-year resident at Beaumont Hospital, say plantar plating for Charcot would be effective for patients without high BMIs who are adherent and have reasonably good bone quality.

Dr. LaPorta says the plantar plating technique involves additional dissection but plates are easier to retrieve and remove. He adds that one places the plantar plate on the tension side of the construct, which enhances the plate’s ability to prevent failure, although screw pullout from diseased Charcot bone can occur.

Can Incomplete Sesamoid Reduction Lead To Bunion Recurrence?

By Brian McCurdy, Managing Editor

An incomplete reduction of sesamoids during bunion surgery can raise the risk of hallux valgus recurrence, according to a recent study in the Journal of Foot and Ankle Surgery.

The study concerned 110 feet, of which 66 had sesamoid reduction and 44 did not have reduction. At an average follow-up of four years, the researchers note although both groups had a similar overall improvement in clinical outcomes, the radiographic outcomes and recurrence rate were significantly worse in patients who did not have sesamoid reduction.

Lawrence DiDomenico, DPM, FACFAS, does not release the sesamoids during bunion surgery. He performs a manipulation of the joint and a triplane correction without an incision and by placing the first ray in anatomic position and stabilizing the first tarsometatarsal joint. He asserts that the only procedure one can use to get a complete three-plane correction is a Lapidus procedure. Once the reduction is good, and all three planes have been reduced, he will place the first ray in an anatomical position and the sesamoids will reduce themselves.

Incomplete reduction can be partially responsible for hallux valgus recurrence, says Dr. DiDomenico, the Section Chief of the Department of Podiatry at St. Elizabeth Hospital in Youngstown, Ohio.

Not obtaining complete reduction of the sesamoids is a less desirable result that he attributes to a lack of reduction of the first ray and thus a lack of reduction of the sesamoid.

“They are really directly related/dependent of one another,” says Dr. DiDomenico. “They go hand in hand.”

In addition to sesamoid reduction, Dr. DiDomenico says surgeons can also attain a good hallux valgus surgical result by getting an intermetatarsal angle as close to 0 as possible or parallel to the lesser metatarsals.

Clarification
In the article “Key Considerations With Dressing Selection In Wound Care” in the September 2018 issue of Podiatry Today, a wound care product listed on page 40 should have been listed as “3M™ Coban™ 2 Two-Layer Compression System (3M).”