INBONE Total Ankle Arthroplasty

The INBONE^® total ankle system is a recently (11/2005) FDA-cleared prosthesis for ankle arthroplasty. The modular design of the system addresses the difficulty in placement of long tibial stems at the ankle. While flexion and disarticulation can be used at the knee and hip joints, respectively, to allow placement of long stems, neither technique is possible at the ankle joint.

The INBONE system addresses this issue through a modular design and a transcalcaneal approach. A guidance hole is drilled through the bottom of the calcaneus. When properly aligned, this small hole should be anterior and medial to the posterior facet of the subtalar joint and should not involve the subtalar joint.

The tibiotalar joint is accessed, and the talar dome is resected. The tibial reamer is then assembled within the joint space, allowing the tibia to be reamed through the small calcaneal hole. After the tibia is reamed, the modular components of the tibial stem are introduced through the tibiotalar joint and assembled.

The tibial stem consists of a top stem segment, zero or more mid-stem segments, a stem base segment, and a tibial base segment. The talar portion is also modular, consisting of talar stem and talar dome components.

Bone cement is applied to the tibial base and talar stem segments.

References

Wright corporate web site with surgical technique and videos.