Managing Osteolysis Following A Failed Ankle Implant
We discussed reconstructive surgical options including revision of the current Agility Total Ankle Replacement, conversion to an Inbone Total Ankle Replacement System (Wright Medical Technology), a custom-stemmed total ankle replacement, a tibiotalocalcaneal arthrodesis with bulk allograft or a below-knee amputation.21-27
Ultimately, we performed revision total ankle replacement by maintaining the stable original tibial component while revising the UHMWPE insert and talar component in order to recreate the height lost by the talar subsidence.16,17 We debrided the periprosthetic tibial cysts and filled them with three-dimensional, geometric metal reinforced polymethylmethacrylate cement to employ immediate stability. Pathologic findings included an abundance of granular histiocytes consistent with a particulate-mediated inflammatory response due to UHMWPE wear debris.
Thirteen months after the surgery, he continues to do well with planned annual surveillance.
Our early results, publication pending, with utilizing three-dimensional metallic reinforced cement augmentation are promising for the management of massive, progressive periprosthetic osteolytic cysts and may provide a useful alternative to impaction bone grafting in specific instances (e.g. elderly patients, periprosthetic cysts with cortical breaches).18
The decision to maintain the Agility Total Ankle Replacement as opposed to alternate options, as we have described above, hinges largely on the stability of the tibial component. Although the massive cysts were present adjacent to the tibial component, the bone-component interface remained stable with osseous ongrowth into the porous coating where the cysts were not present. Accordingly, we did not consider the tibial component itself to have failed or required removal. Interestingly, we have observed this in other patients as well and the talar component is much more frequently unstable when osteolysis occurs.3
When both the tibial and talar components are unstable and have failed, we advise against maintaining the Agility Total Ankle Replacement system and recommend considering alternate reconstructive options. Follow-up is short and anticipated long-term surveillance will provide additional insight to the efficacy of these techniques as further revision would be challenging.
Dr. Prissel is a third-year resident in Podiatric Medicine and Surgery with Distinction in Rearfoot/Ankle Surgery Residency at the Gundersen Medical Foundation within the Gundersen Health System in La Crosse, Wis.
Dr. Roukis is attending staff in the Department of Orthopaedics, Podiatry and Sports Medicine at Gundersen Health System. He is the President-Elect and a Fellow of the American College of Foot and Ankle Surgeons.