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Connections: Total ankle replacement method preserves bone | Winter 2020

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From OHSU Orthopaedics and Rehabilitation

Lara Atwater headshot

Lara C. Atwater, M.D.

Dr. Lara Atwater is a fellowship-trained foot and ankle surgeon. Her clinical interests include total ankle arthroplasty, minimally invasive surgical techniques, deformity correction, and sports injuries. She sees patients at both OHSU in Portland and Tuality Healthcare in Hillsboro.

When painful ankles inhibit daily activities and fail initial therapies, the conversation about fusion versus replacement begins. Until the last decade or two, ankle arthroplasty outcomes were plagued with a variety of issues such as implant loosening and bone deterioration.

Now, a new lateral-approach total ankle implant called the Zimmer Trabecular Metal Total Ankle Replacement (Zimmer TM TAR) addresses these issues and shows strong promise for long-term outcomes and the future of the technology. In the lateral approach, the surgeon cuts through the fibula bone to access the ankle joint, avoiding the fragile neurovascular structures encountered during the traditional anterior surgical approach. The lateral approach allows the surgeon to place the implant much more precisely while removing less native bone.

OHSU is now offering this method of ankle arthroplasty because we believe it offers an excellent solution for more patients and gets them on their feet faster and more functionally. Key benefits over other ankle systems include:

  • Better bone retention: The Zimmer TM TAR requires the smallest amount of bone removal among implants, which keeps the option for revision surgery open. This minimal removal also avoids some complications, such as subsidence, collapse of the talus, and avascular necrosis of the talus.
  • Better implant shape and design: The Zimmer TM TAR’s design matches the curvature of the tibiotalar joint more naturally and restores motion with greater rotational stability. It uses a rigid, crosslinked polyethylene that is the same quality as used in total knee arthroscopy. The microarchitecture of the implant provides a good in-bone growth surface.
  • Greater correction of deformity: Because the lateral approach allows surgeons to shorten or lengthen the fibula based on demands of the medial soft tissues, we can correct a wider range of deformity. This means some patients who have been told their ankles are “uncorrectable” now may have a surgical option beyond fusion.
  • Quicker mobility and fewer complications: Soft tissue healing with the lateral approach is faster and has fewer complications than the anterior approach. Only two weeks after surgery, patients begin bearing weight for range of motion exercises.
  • Reduced risk of additional arthritis: Fusing the ankle joint increases the risk of arthritis in adjacent joints that compensate for loss of ankle motion. Ankle arthroplasty reduces that risk and also offers a solution for patients who already have arthritis in the feet.
  • Greater anticipated longevity: Early data suggests the Zimmer TM TAR will have greater longevity compared to current implant options.

Fusion is a dependable option that may be right for some patients, but the technology of ankle arthroplasty is now at a point where it is often the preferable solution for an active, healthy patient. The primary contraindications are neuropathy and youth. Diabetes and osteoporosis are not necessarily contraindications.

When to refer

  • Patients older than 60.
  • Patients who have failed bracing and/or nonsteroidal anti-inflammatory therapy.
  • Patients who are non-neuropathic.
  • Patients unable to have acceptable quality of life due to ankle instability/pain.

Contact us

We are available to answer questions about all treatment options for orthopaedic issues.

Please call the OHSU Physician Advice and Referral Service at 503‑494‑4567.

To refer a patient, please fax to 503‑346‑6854.