Two Surgery Types Yield Similar Results in Advanced Ankle Osteoarthritis

Patients with end-stage ankle osteoarthritis had similar outcomes from either total ankle replacement (TAR) or ankle fusion surgery, the randomized open-label TARVA trial showed.

At 52 weeks, improvements were similar between the two procedures on the primary outcome of Manchester-Oxford Foot Questionnaire walking/standing (MOXFQ-W/S) domain scores, reported Kashfia Chowdhury, MSc, of University College London, and colleagues.

Mean MOXFQ-W/S improvement from baseline was 49.9 with TAR and 44.4 points with fusion (adjusted difference -5.6 points, 95% CI -12.5 to 1.4), the authors wrote in Annals of Internal Medicine.

The number of adverse events was similar between groups, but more wound healing issues emerged in the TAR group and more thromboembolic events and nonunion were seen in the fusion group.

In addition, a post hoc analysis suggested fixed-bearing TAR may be superior to ankle fusion (adjusted difference -11.1 points, 95% CI -19.3 to -2.9).

“The TARVA study shows how important it is to know the health of the surrounding joints before the patient undergoes surgery, which may involve an MRI, as it could help inform which procedure might be better for the patient,” co-author Andrew Goldberg, MBBS, also of University College London, said in a statement. “Although the risks are not life-threatening, understanding the different risks involved in each procedure is essential.”

The findings point to areas for future research, noted Bruce Sangeorzan, MD, of the University of Washington in Seattle, and colleagues in an accompanying editorial. “In secondary analyses, total ankle replacement seemed to yield better outcomes in patients with surrounding joint arthritis,” they wrote. “This previously unsubstantiated belief was a driver for advancing ankle arthroplasty because ankle fusion performs less well when the surrounding joints are fused or arthritic.”

The results also suggest the type of ankle implant may make a difference, the editorialists observed. “Some implants have two motion segments, and some have only one,” they pointed out. “Prior data have suggested that three-component implants may perform less well, but it was not level 1 evidence.”

“In this study, those that received fixed total ankle replacement implants had greater improvement than those with mobile-bearing implants or ankle fusions,” they added. “This potentially important finding warrants further scrutiny.”

Advanced ankle arthritis leads to severe pain and disability, Chowdhury’s group noted. Once patients progress to end-stage osteoarthritis, they often require surgical treatment, mainly TAR or ankle arthrodesis/fusion. TAR replaces the joint to retain movement, while ankle fusion fuses bones together, prohibiting ankle joint movement but allowing the other 30 foot joints to move.

In TARVA, Chowdhury and colleagues randomized 281 patients with end-stage ankle osteoarthritis to TAR (n=137) or ankle fusion (n=144) across 17 centers in the U.K. between March 2015 and January 2019. Participants were 50 to 85 years old and qualified for either procedure. Procedures were performed by a total of 33 surgeons.

Baseline characteristics were similar between groups. Mean age was 68 and 71% were male; mean body mass index was 30. Over half had a post-traumatic cause of osteoarthritis. Common comorbidities included hypertension or hypercholesterolemia (44%), chronic pain (31%), and other conditions affecting mobility (29%).

Both groups showed similar improvement in pain and social interactions at 26 and 52 weeks. Domain scores for activities of daily living improved in both groups, with more improvement seen in the TAR group than the ankle fusion group at 52 weeks. Total range of motion improved for the TAR group, but was reduced for the ankle fusion group.

The TAR group had more wound healing complications (14% vs 6%) and nerve injuries (4% vs <1%). Although 98% of all received thromboprophylaxis, fewer thrombotic events were seen in the TAR group than the ankle fusion group (3% vs 5%), which may be due to prolonged immobilization in the ankle fusion group, the authors noted.

The symptomatic nonunion rate in the ankle fusion group was 7%. One ankle fusion patient died during follow-up and one TAR patient died after 52 weeks, both unrelated to surgery.

TARVA may be limited by its relatively short duration, the researchers acknowledged. In addition, the study’s pragmatic design may have created heterogeneity of implants and surgical techniques.