Revisional Subtalar Joint Fusions: What You Should Know
When complications occur following subtalar joint fusion, surgeons may need to weigh revisional surgery options in order to correct the deformity. This author discusses common indications for revisional arthrodesis and offers step-by-step pearls to help ensure optimal outcomes.
An isolated subtalar joint arthrodesis has proven over the years to be a successful procedure in the management of numerous hindfoot problems. Outside of an isolated fusion, a successful subtalar joint arthrodesis has been an integral component of a triple arthrodesis in hindfoot pathology.
Authors have reported high rates of patient satisfaction, low rates of complications and low rates of nonunion with subtalar joint arthrodesis.1-6 Rates of union range from 86 to 100 percent for primary isolated subtalar joint fusions.2-4,7-14 Even with encouraging union rates, complications may arise and a revisional subtalar joint arthrodesis may be warranted. Researchers have shown the rate of union diminishes following the failure of previous subtalar arthrodesis.9
As with any revisional surgery, challenges are common with respect to anatomy, fixation, bone stock and function. The increase in scar tissue or fibrosis limits function, and the ease of surgical positioning. Fibrotic tissue also tends to be less vascular in nature, leading to an increase in wound complications. Anatomic dissection and preservation of structures outside the range of arthrodesis are important in minimizing adhesions.
Bone morphology post-fixation or previous surgery can also be complicated. Previous hardware forces a surgeon to alter further placement of fixation. Likewise, existing areas of bone deficit may force one to use a variety of fixation techniques and/or bone graft. The features of revisional fusions are unique.
When Is Revision Indicated?
One often performs a subtalar arthrodesis when the joint is arthritic or destroyed. Surgeons often use the procedure to stabilize the rearfoot in progressive pathology. There are numerous etiologies for lower extremity joint destruction including trauma, congenital deformities, pathological biomechanics, Charcot neuroarthropathy, infection and inflammatory arthridities. With each broad category, fixation may change while the basis behind arthrodesis remains the same. One fuses the joint to eliminate pain and/or reduce deformity.
The indications for revisional arthrodesis vary in comparison to primary fusion. A primary fusion centers upon a painful arthritic joint or the need to create a rigid structure. The joint can be painful and arthritic for a spectrum of reasons. A revisional fusion, on the other hand, can help manage a failed primary fusion or fix a greater deformity.
Indications for revisional subtalar fusions include traumatic arthritis or trauma, malalignment, nonunions, progressive Charcot neuroarthropathy, subsequent infection and inflammatory arthridities. Often, there are greater systemic causes that lead to failed primary fusions and the need for revision. Systemic illnesses and comorbidities may play a role when there is an absence of bone healing. Likewise, controllable factors such as smoking, obesity and malnutrition impede osseous unions.
The need for revision may stem from malaligned successful unions as well. For example, a varus or excessively valgus hindfoot may warrant revision of the primary arthrodesis site. It is the malaligned, fused joint that causes pain elsewhere. Obstacles can arise in any revisional surgery but well planned surgery can help facilitate success.