Metallic hemiarthroplasty can offer a cautious option for grade 3 hallux rigidus

Satisfaction linked to initial cheilectomy, recurrent osteophyte formations and previous procedures.

Issue: November 2006

Metallic hemiarthroplasty is a viable surgical option for patients with significant hallux rigidus who want to preserve motion in the great toe.

But a recent study shows that technical concerns also exist with the procedure.

Michael Aronow, MD [photo]
Michael Aronow

Michael Aronow, MD, and his colleagues at the University of Connecticut, conducted a 20-patient study on first metatarsophalangeal (MTP) joint hemiarthroplasty using the First MPJ hemiarthroplasty implant (BioPro), which has shown good long-term results in a previous study by its developer.

Although the researchers found an 81% satisfaction rate, they also found that the procedure does not restore range of motion to normal and some patients may experience persistent discomfort associated with recurrent osteophyte formation or insufficient cheilectomy during implantation.

Satisfaction also related to whether the patient underwent metallic hemiarthroplasty as an initial procedure.

“There needs to be an adequate cheilectomy performed at the time of the implant insertion,” Aronow told Orthopedics Today. “And if there are any significant biomechanical abnormalities involving the first MTP joint that might make [the patient] more prone to develop recurrent hallux rigidus, [surgeons should] consider addressing these at the initial procedure.”

Aronow presented the study results at the American Orthopaedic Foot and Ankle Society annual summer meeting.

Patient satisfaction

AOFAS [logo] At the average 49-month follow-up, 15 patients (16 feet) completed a satisfaction questionnaire. The patients’ average age was 60 years (range, 50 years to 76 years). Thirteen patients (14 feet) returned to the office for physical and radiographic evaluation.

Of the five patients who did not participate: one experienced infection at 10 weeks after implantation and had the prosthesis removed; one died; one did not return the questionnaire; and two patients could not be located.

All patients had Hattrup and Johnson Grade 3 hallux rigidus that had failed previous conservative treatment. Four patients underwent previous surgeries, including three cheilectomies and one tissue interposition arthroplasty, Aronow said. Subsequent surgical procedures included one implant removal for infection and two revision cheilectomies.

At follow-up, patients reported four of the 16 great toes were pain free. Fourteen patients (88%) reported that their pain decreased since preop, with no patients complaining of increased pain.

Patient satisfaction ratings were as follows:

Very satisfied for eight feet (50%);
Satisfied but with reservations for five feet (31%); and
Dissatisfied for three feet (20%).

Thirteen recipients (81%) said they would still have the procedure performed again and 14 patients would recommend the procedure to a friend, Aronow said.

A preoperative image of a 61-year-old man with severe hallux rigidus.

The same man at initial postop evaluation after undergoing metallic hemiarthroplasty.

This image shows the radiographic results of the 61-year-old man at 33 months after metallic hemiarthroplasty for severe hallux rigidus.

Images: Aronow M

Clinical results

At final evaluation, range of motion averaged 37° for first MTP joint dorsiflexion relative to the first metatarsal axis. First MTP plantarflexion averaged 3° and the hallux valgus angle averaged 14°.

Shown here is another postop radiograph of the same 61-year-old man. Researchers found he had an AOFAS Hallux Metatarsophalangeal-Interphalangeal Score of 95 and a range of motion of 30°.

The AOFAS Hallux Metatarsophalangeal-Interphalangeal Score averaged 77 (range, 59 to 95). Researchers found six feet had moderate or significant recurrent dorsal osteophytes, six feet had minimal or mild osteophytes and two feet had no residual osteophytes.

The investigators cited several factors as being related to patient satisfaction. “There were five patients who had a generous initial cheilectomy (below the dorsal cortex of the metatarsal diaphysis) and mild recurrent osteophytes formations – all five of those patients were very satisfied,” Aronow said. “They had … no pain and their average AOFAS score was 84, which was higher than the 77 found for the remaining patients in the study.”

Those patients who underwent the metallic hemiarthroplasty as an initial procedure for their hallux rigidus had better results on average with 83% having no or mild occasional pain, an average AOFAS score of 81 and a 92% satisfaction rate.

In contrast, only 25% of the four patients who had a previous cheilectomy or tissue interposition arthroplasty had no or mild occasional pain, their average AOFAS score was 63 and they had a 50% satisfaction rate, Aronow said.

For more information:
Aronow M, Leger R, Sullivan R. The results of first MTP joint hemiarthroplasty in grade 3 hallux rigidus. Presented at the American Orthopaedic Foot and Ankle Society 22nd Annual Summer Meeting. July 14-16, 2006. La Jolla, Calif.
Dr. Aronow has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.