Metal-Free Total Ankle Replacement

Patients suffering from severe arthritis now have an option for total ankle replacement that offers increased mobility and pain relief without permanent metal implants.

Researchers at the University of California (UC) San Diego (USA) developed the two-hour minimally invasive surgical procedure, which includes removing the damaged cartilage around the ankle joint through a four-centimeter incision. A collagen material processed from either human or animal collagen sources is then molded into the joint, where it adapts to the contour of the patient's ankle. Since the collagen is non-allergenic and sterile in nature, there is no risk of rejection nor need for the patient to take immunosupressors. To allow the material to integrate fully with the ankle joint, a temporary external device is used to stabilize the joint area while distracting (opening) it for a period of 4-6 weeks. The cylinder-shaped device, which is attached by small pins, serves as a shock system to keep the joint free from friction and movement until healing is complete. The device is then removed entirely, which keeps the patient's ankle free from any metal parts.

"Within three weeks after surgery, we see an incorporation of tissue onto the damaged cartilage,” said procedure developer Daniel K. Lee, D.P.M., a podiatric foot and ankle surgeon. "The idea here is to avoid fusion of the ankle and to add longevity to the joint. We want to give patients as much mobility as possible so they can get back to the activities they love the most.”

Patients have the option of total joint replacement in the hips, knees, and ankle with titanium and other metal devices. However, while metal-based implants are well suited for hips and knees, metal replacements for the ankle show a high level of failure and unwanted complications such as metal collapse and breakage. Moreover, once an ankle is replaced with metal, options for revision surgery are little to none.


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University of California San Diego