Total Ankle Arthroplasty for the Treatment of Symptomatic Nonunion Following Tibiotalar Fusion

Takedown of Ankle Fusions and Conversion to Total Ankle Replacements

BACKGROUND

With ankle replacements gaining credibility, there is a small subset of patients who might benefit from a conversion of an ankle fusion to a replacement. The objective of this study is to present clinical and radiographic results of patients who had their ankle fusion converted to total ankle arthroplasty (TAA).

METHODS

Patients presented to the senior author with ongoing ankle pain following fusion or increasing pain after a period of relative comfort after an ankle fusion. Outcomes were evaluated preoperatively and postoperatively with the Veterans Rand Health Survey (VR-12), Ankle Osteoarthritis Scale (AOS), and visual analog scale (VAS) pain scale. A patient satisfaction survey was also distributed.

RESULTS

All ankle fusion conversions between April 2010 and December 2019 were included. Fifty-one patients (30 females) with the mean age of 62.6 (range, 37-83) years were followed. Mean follow-up was 4.2±2.3 (range, 2-11.5) years. Two patients were lost to follow-up (1 is deceased). Pre- and postoperative mean patient-reported outcome scores were all significantly different between groups except VR-12 mental subscale scores. VR-12 physical scores improved from 28.7±8.9 preoperatively to 38.9±9.9 (P < .001) postoperatively; VR-12 mental score was stable. AOS pain and disability subscales similarly improved: 55.9±24.4 to 27.9±25.4 (P < .001) and 61.7±21.1 to 31.1±25.7 (P < .001), respectively. VAS pain improved from a mean of 64.5±27.3 to 29.4±27.7 (P < .001). There was no tibiotalar dorsiflexion or plantarflexion with the ankle fusion. Initial postoperative visit revealed that average dorsiflexion was 10.9±5.93 degrees and average plantarflexion was 14.1±5.22 degrees. At the latest follow-up, dorsiflexion improved significantly to 15.5±6.33 degrees (P < .001), with no significant improvement in plantarflexion (P = .980).

CONCLUSION

In this single-surgeon longitudinal study of 51 patients with a painful, malaligned, or nonhealed ankle fusion treated with an ankle replacement, we found highly satisfactory functional outcomes at an average of 4.2 years. Continued long-term follow-up will reveal whether the longevity of these replacements is comparable to primary replacements.

Outcomes of Ankle Arthrodesis Conversion to Total Ankle Arthroplasty: A Systematic Review

Ankle arthrodesis (AA) provides reliable pain relief, good patient satisfaction scores, and improved overall function. However, this procedure has been associated with numerous complications and sequelae, such as pseudoarthrosis, malunion, gait abnormalities, increased demand on surrounding joints, and a long period of convalescence. Conversion to total ankle arthroplasty (TAA) is a potential option in the management of these complex and challenging situations. The purpose of this study is to investigate the outcomes of AA conversion to TAA. A systematic review of electronic databases was performed. Six studies involving 172 ankles met inclusion criteria. The weighted mean preoperative Visual Analogue Scale (VAS) score at the time of TAA conversion was 7.8 and the weighted mean postoperative VAS score at the time of final follow-up was 2.5. The weighted mean preoperative AOFAS score at the time of TAA conversion was 32 and the weighted mean postoperative AOFAS score at the time of final follow-up was 72.4. The rate of salvage tibiotalocalcaneal arthrodesis was 2.3% and rate of transtibial amputation was also 2.3% after attempted conversion from initial AA to TAA. Conversion of AA to TAA appears to be a viable option to improve patient outcomes and prevent extensive hindfoot arthrodesis and transtibial amputation. More prospective studies with consistent reporting of outcomes, complications, and revision rates with long-term follow-up are needed.

Mini-open vs. Transfibular Approach for Ankle Arthrodesis, Which Approach is Superior in Joint Preparation: A Cadaver Study

BACKGROUND

Arthrodesis is considered the gold standard for end-stage ankle arthritis in patients who fail conservative management. Achieving union is paramount while minimizing complications. An essential item for successful union is preparation of the articular surface. Our study aims to evaluate the difference in joint preparation between direct lateral and dual mini-open approaches.

MATERIALS AND METHODS

Ten below knee fresh-frozen specimens were used for this study. Five were prepared through lateral approach, and five using dual mini-incisions. After preparation, all ankles were dissected and images of tibial plafond and talar articular surfaces were taken. Surface areas of articulating facets and unprepared cartilage of talus, distal tibia, and distal fibula were measured and analyzed.

RESULTS

A greater amount of total surface area was prepared with the mini-open approach in comparison to the transfibular approach. Percentage of prepared surface area of total articulating surface (including talus and tibia/fibula), talus, tibia, and fibula with the transfibular approach were 76.9%, 77.7%, and 75%, respectively. Percentages were 90.9%, 92.9%, and 88.6% with the mini-open approach. When excluding medial gutter, there was no significant difference between techniques (83.94% vs. 90.85%, p = 0.1412).

CONCLUSION

Joint preparation with the mini-open approach is equally efficacious as the transfibular approach for the tibiotalar joint. The mini-open approach does provide superior preparation of the medial gutter and inferior tibial surface which may help to increase union rates and decreased complications.

LEVEL OF EVIDENCE

V.

Converting Ankle Arthrodesis to a Total Ankle Arthroplasty

Several articles in the literature discuss the positive results of converting a painful ankle fusion to an ankle replacement. Our results confirm that in well-selected cases a conversion to a total ankle replacement is not only possible, but also significantly improves quality of life and reduces pain. The outcome of a total ankle replacement after an ankle fusion depends to a degree on the method of fusion. Less destructive fusion that is arthroscopic has better results than conventional transfibular open fusions. Absence of a fibula should be an absolute contraindication for a conversion.

Revision of the Malaligned Ankle Arthrodesis

A malaligned ankle arthrodesis is a painful and complicated pathology. Deformities may be present in the frontal, sagittal, or transverse plane or a combination of planes. Thorough preoperative evaluation of the deformity and the patient as a whole is crucial to successful revision. Surgical site for revision should be based on center of rotation of angulation, when possible. Revision commonly is performed through opening wedge osteotomy. Closing wedge and focal dome osteotomies, however, are excellent options. Revision also may be performed through external fixation or total ankle replacement. Although the literature is not rich with data, the options discussed provide favorable results.

Ankle Arthrodesis Versus Total Ankle Arthroplasty

Reoperation rates are higher in total ankle arthroplasties (TAAs) compared with ankle arthrodesis. Infection rates for primary TAAs are 1.4% to 2.4%. The survival rate of TAA is approximately 75% to 90% at 10 years. Arc of motion is maintained with TAAs compared with ankle arthrodesis. Ankle arthrodesis increases arc of motion through the talonavicular joint. Several factors are strong reasons to favor ankle fusion rather than TAA. TAA and ankle arthrodesis are effective treatments of end-stage ankle arthritis but the choice must be tailored to individual patients.