The human foot is a marvel of biomechanical engineering, composed of 26 bones and 33 joints that work in concert to provide both flexible shock absorption during gait and a rigid lever for push-off. When this intricate system is disrupted by arthritis, severe deformity, or instability, the resulting pain can be debilitating. For patients with end-stage hindfoot pathology who have exhausted conservative treatments, a surgical procedure known as triple arthrodesis offers a powerful, albeit irreversible, solution. Triple arthrodesis is a salvage procedure that involves the surgical fusion of the three major joints of the hindfoot: the subtalar joint (talus and calcaneus), the talonavicular joint, and the calcaneocuboid joint . While the operation successfully eliminates pain and corrects deformity by sacrificing motion, it requires a prolonged recovery and carries a risk of long-term adjacent joint arthritis, making patient selection critical for success.
Historical Context and Surgical Rationale
Originally described by Edwin W. Ryerson in 1923, triple arthrodesis was initially developed to treat paralytic deformities resulting from poliomyelitis . By fusing the three key joints of the hindfoot, surgeons could take a flail, unstable foot and convert it into a rigid, plantigrade (flat-on-the-ground) structure suitable for ambulation. Over the past century, the indications have evolved. Today, while neuromuscular conditions like Charcot-Marie-Tooth disease and cerebral palsy remain indications, the procedure is most commonly performed in adults for posttraumatic arthritis, rheumatoid arthritis, or the end-stage collapse of the posterior tibial tendon leading to a rigid flatfoot deformity .
The rationale behind the procedure is straightforward yet transformative. The hindfoot is the interface between the leg and the ground; if it is misaligned or arthritic, every step transmits abnormal forces up the kinetic chain. By fusing these joints, the surgeon abolishes the painful motion at the arthritic surfaces and locks the hindfoot into a corrected, stable position. This allows for the restoration of a pain-free, propulsive gait, with one study noting that 95% of patients remained satisfied with their outcome up to 44 years post-surgery .
Indications and Patient Selection
Triple arthrodesis is not a first-line treatment. Due to the permanent loss of motion and the technically demanding nature of the surgery, it is strictly considered a “salvage procedure” reserved for patients with significant disability who have failed non-operative management, including bracing, activity modification, and anti-inflammatory medications .
The primary indications include painful, rigid deformities that are unbraceable. The most common scenario is a rigid flatfoot deformity (pes planovalgus), where the arch has collapsed, the heel bone rolls outward, and the joints have become stiff and arthritic . Other key indications include posttraumatic arthritis following a calcaneus or talus fracture, neuroarthropathy (Charcot foot) that has become stable but ulcerated or deformed, and tarsal coalitions (abnormal bone fusion) causing progressive pain . The goal is always to create a stable, balanced foot. If a less extensive procedure, such as a single joint fusion or osteotomy, would suffice, triple arthrodesis should be avoided due to its significant long-term consequences .
The Procedure and Biomechanical Aftermath
Surgically, the procedure involves denuding the cartilage from the three joints and fixing the bones together, typically using screws or plates to maintain compression while the bones biologically fuse into one mass . Traditionally performed through an open incision, recent advances have seen the rise of minimally invasive surgery (MIS) techniques. Research comparing the two approaches suggests that while both offer similar improvements in pain and function, MIS techniques significantly reduce the risk of wound dehiscence, a common complication in the open approach due to the poor soft-tissue envelope of the hindfoot .
However, the success of the fusion comes at a biomechanical cost. The hindfoot is designed to invert and evert (rock side-to-side) to accommodate uneven terrain. By fusing it, the surgeon transfers the mechanical stress that normally dissipates through the subtalar and midtarsal joints directly to the adjacent, unfused joints—specifically the ankle joint (tibiotalar) and the midfoot joints . A finite element study demonstrated that triple arthrodesis significantly alters strain distribution in the distal tibia, shifting peak stresses to the lateral aspect of the ankle . Consequently, while the patient’s original hindfoot pain is resolved, they are at high risk of developing progressive arthritis in the ankle joint over 10 to 15 years, a condition known as “adjacent segment disease” .
Outcomes and Modern Perspectives
Despite the trade-offs, patient-reported outcomes are generally excellent for appropriately selected individuals. A retrospective study of patients with adult acquired flatfoot deformity found a significant decrease in Visual Analog Scale (VAS) pain scores, dropping from 5.4 preoperatively to 2.55 postoperatively at an average follow-up of over five years . Patients typically report being able to walk longer distances with less pain, though they may find running or navigating rocky trails difficult due to the loss of side-to-side motion.
The decision to perform a triple versus a “double” arthrodesis (fusion of only the subtalar and talonavicular joints) is a topic of debate. Some surgeons argue that if the calcaneocuboid joint is mobile and non-arthritic, it can be spared to preserve some motion. However, research indicates that adding the third fusion does not significantly increase the rate of complications, nonunion, or hardware removal compared to double or single fusions . Ultimately, the choice depends on the surgeon’s assessment of which joints are the source of the patient’s specific deformity and pain.
Triple arthrodesis remains a cornerstone of orthopedic foot and ankle surgery. By sacrificing the complex motion of the subtalar, talonavicular, and calcaneocuboid joints, it provides a predictable, durable solution for patients suffering from severe flatfoot, arthritis, and neuromuscular deformity. It effectively transforms a painful, dysfunctional foot into a stable, plantigrade platform for walking. However, this is a procedure of last resort, reserved for patients willing to accept a rigid foot and the long-term risk of ankle arthritis in exchange for immediate, life-altering pain relief. As surgical techniques evolve with MIS approaches to reduce wound complications, the core principle remains unchanged: triple arthrodesis is a powerful tool that, when applied judiciously, offers a “second chance” at a functional life for those with debilitating hindfoot conditions.