A Guide To The Triple Arthrodesis For Hindfoot Deformities
The use of triple arthrodesis for correction of neuromuscular cavus has been well documented with long-term follow-up studies of up to 40 years.3 Satisfaction rates for treatment of neuromuscular disease with triple arthrodesis range from 23 to 95 percent though the low end of this spectrum represents patients with progressive neuromuscular dysfunction and dynamic muscle imbalance.
One of the strongest direct indications for triple arthrodesis is hindfoot arthritis. If there is post-traumatic, degenerative or inflammatory arthritis in one or several of the hindfoot joints, triple arthrodesis may serve to limit the pain associated with motion at these damaged joints.
Surgeons can best treat arthritis confined to one joint with arthrodesis of that joint alone. However, when it comes to severe arthritis, multiple joint arthritis or arthritis associated with significant deformity, one should perform a triple arthrodesis as it confers greater stability.
Use caution in performing an isolated talonavicular fusion as this is associated with a risk of nonunion and leaves the surgeon with limited options for correction because of bone loss and erosion.4 In performing limited arthrodesis of the talonavicular and subtalar joints, there is potential for inferior subluxation of the cuboid relative to the calcaneus.4 If early degenerative changes are present at joints adjacent to the symptomatic joint, surgeons should also pursue fusion for these joints as arthritic progression will likely occur once one fuses any of the joints in the triple joint complex.
In addition to the aforementioned indications, other indications for the triple arthrodesis include the reconstruction of neglected calcaneal fractures, late reconstruction of tarsal coalition, neglected clubfoot and a wide array of severe pathology of the hindfoot. Long-term outcomes data supports the use of triple arthrodesis in patients with severe deformities and suggests that one can obtain good and excellent outcomes with appropriate patient selection.5,6
What The Research Says About Incision Approaches
The literature has described three different incisional approaches for the triple arthrodesis. The classic approach is the two-incision approach, which allows for easy visualization of the joints. More recent literature has described both the medial and lateral approaches. The medial approach has had equal surgical outcomes with no increase in surgical durations.7 However, authors also note that one should reserve the medial approach for patients with lateral skin compromise, such as those with rheumatoid arthritis.7
Cadaveric studies have shown that a purely lateral approach can remove only 38 percent of cartilage from within the talonavicular joint.8 Study authors attributed this to a poor appreciation of the anatomy of the talar head and poor surgeon observation. Although surgeons removed 90 percent of cartilage from the calcaneocuboid joint and 80 percent from the talocalcaneal joint, the poor access to the talonavicular joint makes it impossible to recommend the lateral approach as it could lead to a nonunion of the talonavicular joint.
A Brief Guide To Surgical Technique
Regardless of the approach, it is important to emphasize careful anatomic dissection while taking care not to damage the numerous vital structures one will encounter through the extensive dissection needed for adequate exposure. When using a lateral approach, avoid damaging the sural nerve, peroneal tendons and superficial peroneal nerve. Retract the tibialis anterior and neurovascular bundle while working through the medial incision.