SLR - March 2019 - Julio D. Perez-Mustelier

Early Clinical and Radiographic Outcomes of Trabecular Metal Total Ankle Replacement Using a Transfibular Approach

Reference: Barg, A., & Saltzman, C. (2017). Early Clinical and Radiographic Outcomes of Trabecular Metal Total Ankle Using Transfibular Approach: A Minimum Follow-Up of Two Years. Foot & Ankle Orthopaedics.

Scientific Literature Review

Reviewed by: Julio D. Perez-Mustelier, DPM
Residency Program: Bethesda Hospital East

Podiatric Relevance: In regard to treating end-stage ankle osteoarthritis, total ankle replacements have become an increasingly common treatment modality. This article focuses on an atypical approach to total ankle replacement, which seeks to minimize or prevent wound-healing problems and injury to surrounding neurovascular structures. The objectives of the study were to determine the intraoperative and perioperative complications, assess early prosthetic component stability, including surgical revision for any reason, determine short-term total ankle replacement survivorship and assess patients’ short-term postoperative pain relief and ankle range of motion.

Methods: From October 2012 to December 2014, 55 primary total ankle arthroplasties using the Zimmer Trabecular Metal Total Ankle implant were performed in 54 patients by a single surgeon. Clinical assessment, including pain evaluation and measurement of ankle range of motion, was conducted preoperatively and at the latest follow-up. Using weightbearing films, the angular alignment of the tibial and talar components were analyzed to evaluate the bone-implant interface. Intraoperative and postoperative complications, revision surgeries and survivorship were evaluated. The exclusion criteria for total ankle replacement were unrealistic expectations of activity after surgery, a compromised soft-tissue envelope, active infection, substantial ankle deformity, neuropathic arthropathy and bone stock unable to support the implant. All patients were seen preoperatively and postoperatively in an outpatient clinic by fellowship-trained independent examiners. Additionally, all radiographs were examined independently by two orthopaedic foot and ankle surgeons.

Results: Implant survival was 93 percent at 24 months of follow-up. There were three revisions of a tibial component due to aseptic loosening. In 10 of the 55 cases, a secondary procedure was performed during follow-up. The mean follow-up duration was 26.6 months. No delayed union or nonunion was observed for fibular healing. The average visual analog scale (VAS) pain score decreased significantly, from 7.9 to 0.8. The average total range of motion increased significantly, from 22.9 to 40.2. Intraoperative medial malleolar fracture and talar fracture were observed in one patient each.

Conclusions: Of the 55 ankles, 60 percent were completely pain-free at the latest follow-up. Preoperatively, nine ankles had a substantial lack of dorsiflexion, and at final follow-up, all patients reached at least neutral position. This study concludes less pain with implantation of this particular total ankle system using the lateral approach with somewhat ease of reproducibility. Additionally, the authors found the fibular osteotomy healed routinely, ingrowth and stability of the talar component occurred reliably, ingrowth and stability of the tibial component failed in approximately 10 percent of the patients. While a majority of total ankle replacement designs utilize an anterior approach for primary implantation, the lateral approach potentially avoids anterior wound-healing problems and injury to neurovascular structures.

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