STAR Ankle Replacement With Concomitant Talonavicular Fusion
By Keith L. Wapner, M.D.
A 62-year-old female had a history of rheumatoid arthritis treated with Methotrexate, Mobic, and Humira. She had a trial of bracing with the use of a Southwest brace, but was unable to get satisfactory relief of her pain. She described pain in the right ankle and hindfoot that worsened over the past several years. She has problems ambulating on both flat and uneven surfaces, as well as on stairs.
On physical examination she demonstrated an antalgic gait pattern. There was tenderness to palpation over the anterior ankle joint, as well as the talonavicular joint of the right foot. There was associated crepitation with joint motion at the talonavicular level. Range of motion revealed limited ankle motion in dorsiflexion to 0 degrees and plantar flexion to 20 degrees. Subtalar motion is 5 degrees of eversion and 10 degrees of inversion. Transverse tarsal joint motion could not be obtained because of severe pain. Her motor exam was intact. Radiographs are shown in figures 1 and 2 demonstrating the arthritic changes of both the ankle and talonavicular joint.
In light of her history of rheumatoid disease and concerns of associated hindfoot joint involvement, a preoperative CT scan was performed which revealed arthritic changes in the talonavicular joint and ankle joint, but only minimal changes in the subtalar joint and calcaneocuboid joint, as seen in figures 3 and 4.
Treatment options were discussed and the patient elected to undergo a STAR™ total ankle replacement with concomitant talonavicular joint fusion.
At the time of the surgery, the total ankle replacement was performed first. In the preparation performing the total ankle, the dorsal osteophytes at the level of the talonavicular joint were removed to allow normal motion of the talonavicular joint. This was important to be able to judge proper placement of the talar component and make sure that the foot would be in a plantigrade position postoperatively.
Once the total ankle had been placed, the talonavicular joint was distracted and the subchondral bone was removed. It was then fixed using the lag technique with a 4.5 fully threaded screw.
The postoperative protocol was not altered from the normal STAR protocol and the patient was advanced to weightbearing and range of motion with the normal progression.
Radiographs at 6 weeks demonstrated that the talonavicular joint appeared fused, as seen in figures 5 and 6.
Postoperatively, she has 0 degrees of dorsiflexion and 30 degrees of plantar flexion at the level of the ankle. Her subtalar joint motion is limited to 5 degrees of inversion and 0 degrees of eversion, but her dorsal pain at the level of the talonavicular joint as well as her ankle pain has been relieved.
There is debate over whether more than one operative procedure should be performed at the time of the STAR™ total ankle replacement. Some surgeons feel that all concomitant procedures should be performed ahead of time and healed prior to performing a STAR™ total ankle replacement. Some surgeons feel it depends on the nature of the secondary procedure and how much operative time would be added or if the postoperative protocol would be changed.
Questions for discussion:
- In instances of an isolated talonavicular fusion, because there is no separate incision that needs to be made and the added operative time is minimal, is it reasonable to do this concomitantly? Which other procedures would fall into this category?
- Is it necessary to remove the dorsal osteophytes at the talonavicular joint level in order to assess the hindfoot alignment properly in the performance of the STAR ankle replacement?
- Should the decision to add secondary procedures at the time of STAR arthroplasty be influenced by how the postoperative protocol would be changed?