SLR - January 2020 - Fernando Ramirez
Reference: Scott D., Steele J., Fletcher A., Parekh S., Early Outcomes of 3D Printed Total Talus Arthroplasty. Foot and Ankle Specialist. September, 2019.Scientific Literature Review
Reviewed By: Fernando Ramirez, DPM
Residency Program: Kaiser SF Bay Area Foot and Ankle Surgery – Oakland, CA
Podiatric Relevance: Talar avascular necrosis (AVN) is a difficult condition to treat with limited treatment options. Talar AVN is most commonly caused from a traumatic injury. However, AVN may arise due to a variety of different factors such as chemotherapy, prolonged steroid use or high alcohol intake. Talar AVN treatment begins with conservative management such as bracing and activity modifications. These options do not directly treat the underlying pathology, which leads to high rates of nonimproved symptoms. Previously, operative management includes pan-talar fusions, tibiotalar calcaneal fusions, revascularization procedures and even talectomies. These options lead to decreased hindfoot range of motion and arthritic changes to the adjacent joints. More recently 3D printed total talar replacements (TTRs) have developed as an option for talar AVN. Currently there is little research on this surgical procedure.
Methods: A level IV retrospective case series was performed on 15 patients who underwent TTRs for talar AVN over a two-year period. All surgeries were performed by a single surgeon. Custom 3D printed total talus were sized based on contralateral talus computed tomography. Patients were kept non-weight bearing for three weeks postoperatively, they were then allowed to weight bear as tolerated in a CAM walker for an additional three weeks. Preoperative versus postoperative hind foot range of motion, radiographic foot alignment, and patient reported outcomes were compared. Patient reported outcomes were evaluated using Visual Analog Scale (VAS) and Foot and Ankle Analog Scores (FAOS).
Results: At an average follow up of 12.8 months there was a significant improvement of the VAS decreasing from seven preoperatively to 3.6 at final follow up. There was also an increase in the five subcategories of the FAOS all reaching statistical significance except one. Although not statistically significant, there was an upward trend in ankle and subtalar joint range of motion postoperatively. There was no significant difference in the preoperative vs. postoperative anatomic alignment when radiographically evaluating tibiotalar alignment, talar tilt angle, talar declination and Meary’s angle. There was one postoperative complication (6.7 percent) which required an incision and drainage due to wound dehiscence. This patient did well after the second procedure with no further complications. No other patients required additional procedures.
Conclusions: The authors concludes based on these early results, that 3D printed TTRs are a safe surgical option for patients with end stage talar AVN. Furthermore, they reported significant improvements of both functional outcome and pain scores. Due to TTRs being a relatively new treatment option there is limited literature on the topic. Before this study there has been a paucity of literature with only one to two patient case reports. Some limitations of this study include being retrospective, having a small patient size and short term follow up. However, this article brings to attention TTRs as a reasonable treatment option for talar AVN. Further studies incorporating clinical and cost analyses with long term follow up and larger patient cohorts are needed.