We have entered an era where total ankle arthroplasty (TAA) is accepted as a rational approach for patients with degenerative arthritis of the ankle. TAA results have been shown to be an improvement over arthrodesis in some recent comparative trials.
That was not always the case, however. In the 1980s, the orthopaedic community attacked ankle joint replacement with gusto, and numerous prosthetic designs were introduced with great enthusiasm based on short-term cohort studies. Unfortunately, the concept of TAA was all but buried as disappointing longer-term results with those older prosthetic designs appeared in the scientific literature. It took a full decade for new designs to appear and be subjected to longer-term follow-up studies before surgeons could gain ready access to more reliable instrumentation and prostheses. The producers of these implants behaved responsibly in this regard, facilitated by an FDA approval process that had increased in rigor.
In the December 21, 2016 issue of The Journal, Hofmann et al. publish their medium-term results with one prosthetic design that was FDA-approved in 2006. Implant survival among 81 consecutive TAAs was 97.5% at a mean follow-up of 5.2 years. There were only 4 cases of aseptic loosening and no deep infections in the cohort. Total range of motion increased from 35.5° preoperatively to 39.9° postoperatively.
The fact that a high percentage (44%) of ankles underwent a concomitant procedure at the time of TAA attests to the need for careful preoperative planning for alignment of the ankle joint and the need for thorough assessment of the hindfoot. The fact that a substantial percentage (21%) of ankles underwent another procedure after the TAA attests to the need for thoughtful benefit-risk conversations with patients prior to TAA.
I think the TAA concept and procedure are here to stay, but we still have much work to do in fine-tuning prosthetic designs and instrumentation and enhancing surgeon education for more reliable outcomes.
Marc Swiontkowski, MD
One thought on “JBJS Editor’s Choice: Advances in Ankle Replacement”
Improving functional results in debilitating ankle arthritis is always welcome. However, considering improvement of TAR quoting improved mobility in a questionable range seems hazardous. Brodsky et al (Bone Joint J. 2016 Oct;98-B(10):1369-1375. “Abnormalities of gait caused by ankle arthritis are improved by ankle arthrodesis”. Brodsky JW, Kane JM, Coleman S, Bariteau J, Tenenbaum S) have shown in a prospective series of 20 ankle fusions that the total sagittal range of movement did not change significantly. Other parameters such as revision rates after TAR amongst others place this kind of surgery still in the shadow of well-oriented ankle fusions, especially when considering economical factors.
K.Klaue MD PhD