Hindfoot arthritis comprises a spectrum of painful and debilitating conditions. These conditions are common, but their exact incidence is unknown. Etiologic mechanisms include trauma, deformity, inflammatory arthritides, degenerative arthritis, or idiopathic. Joint disease and clinical disability progress in tandem and result in increasing difficulty with shoe wear and ambulation. Nonsurgical measures are the first line of treatment; when these fail, the preferred surgical procedure is arthrodesis.

The hindfoot consists of the talus, calcaneus, cuboid, and navicular bones, which articulate through the subtalar (ST), calcaneocuboid (CC), and talonavicular (TN) joints. The ST joint consists of posterior, middle, and anterior facets. The TN and CC joints are referred to as the transverse tarsal joint. The spring ligament, an important stabilizer of the medial arch, supports the TN joint plantarly.¹ These joints work synchronously and are mainly responsible for inversion and eversion of the hindfoot to accommodate ambulation on uneven ground. Coupled movements of these joints allow the foot to act as a shock absorber at heel strike and to become a rigid lever at push-off. The ST joint everts at heel strike, which aligns the TN and CC joints parallel to each other. This effectively “unlocks” the transverse tarsal joint and midfoot, allowing motion and flexibility to absorb impact and balance the foot on the ground. As the foot progresses through the stance phase, the ST joint inverts, causing the TN and CC joint axes to diverge and “lock” the midfoot to create a rigid lever for push-off.²

Considering this complex coupling of multiple joints and facets, it can be difficult to measure their individual motion. Although the entire hindfoot joint complex is involved in inversion and eversion, the transverse tarsal joint is responsible for 26% of foot dorsiflexion and plantar flexion.³ Cadaver studies of residual joint motion after selective arthrodeses have helped to increase understanding of the complexity of hindfoot motion. Isolated CC arthrodesis had little effect on ST motion but decreased TN motion to 67% of its normal value. Subtalar arthrodesis limited CC and TN motion to 56% and 46% of their normal values, respectively. Isolated TN arthrodesis had the most substantial effect, reducing both ST and CC motion to less than 8% of normal values.^2,4,5

Hindfoot arthritis develops in much the same way as arthritis affecting other joints. It is the result of direct cartilage or chondrocyte damage from acute macrotrauma, repetitive microtrauma, abnormal weight-bearing stress from articular incongruity, joint malalignment, adjacent joint arthrodesis, or increased shear stress from ligamentous instability.¹ Any soft-tissue or bony pathology that causes hindfoot deformity can lead to degenerative changes.

The calcaneus is the most commonly fractured tarsal bone, and subtalar posttraumatic arthritis can occur secondary to intra-articular calcaneal fractures. When these injuries are managed nonsurgically, there may be as much as a fivefold increase in the incidence of late ST arthrodesis.⁶ Damage to the articular surface can occur at the initial injury and over time with the malreduced joint causing uneven loading patterns and progressive cartilage wear.⁷

Inflammatory arthritis also commonly affects the hindfoot. Foot and ankle pain will develop in more than 90% of patients with rheumatoid arthritis (RA). Joint destruction is the result of synovial inflammation leading to cartilage erosion and periarticular bony resorption. This is exacerbated by subsequent ligamentous laxity and possible tendon rupture. Substantial deformity can lead to increased stress on the cartilage and accelerated wear.^8,9

Iatrogenic hindfoot arthritis occurs when foot or ankle surgery leads to increased loads on adjacent joints with subsequent adjacent joint degeneration. One noteworthy example is hindfoot arthritis that develops after ankle arthrodesis. In one study, investigators noted a 90% incidence of adjacent hindfoot arthritis after ankle arthrodesis with a mean follow-up of 22 years.¹⁰ Long-term follow-up of adjacent joint disease following hindfoot fusion demonstrated high rates of secondary arthritis tibiotalar (73%), subtalar (58%), talonavicular (66%), and calcaneocuboid (54%); however, the presence of arthritis is not correlated with increased pain at 10-year follow-up.¹¹

Patients with symptomatic hindfoot arthritis report pain, swelling, and stiffness of the foot. The pain is often localized to the sinus tarsi or to areas just distal to the malleoli. Walking on uneven surfaces such as grass, gravel, or sand exacerbates the pain associated with hindfoot arthritis. It is important to obtain a patient’s history of previous trauma or surgeries of the foot.

With the patient standing and undressed from the knees down, overall alignment should be assessed and any deformities noted and determined to be flexible or rigid. The Coleman block test can be used to establish the flexibility of a varus hindfoot deformity and guide treatment.¹² Similarly, the flexibility of the hindfoot in long-standing planovalgus deformity is also critical in guiding treatment.¹³ The hindfoot joints should be assessed for motion as well as point tenderness. Any limited or painful motion may indicate joint degeneration and should be compared with the contralateral side. Diagnostic injections of local anesthetic may aid in identifying specific joint involvement. The ST joint can typically be injected in the office setting, whereas injections of the TN and CC joints often necessitate image guidance. Fluoroscopy remains the preferred method for intra-articular injections in the foot and ankle; however, there has been recent interest in the use of ultrasonography guidance for diagnostic injections to improve accuracy without ionizing radiation exposure. Although these injections may help to localize pathology, communications can exist between these joints and should be considered when using these diagnostic tests to guide treatment.^14,15 It is also important to assess ankle motion to determine if there is an Achilles contracture; if present this will need to be addressed in treatment. A Silfverskiöld test can help to determine if the contracture is in the gastrocnemius or the triceps surae.¹⁶ A detailed neurovascular examination is also critical. Any motor weakness or sensory loss should be noted because this may indicate a neuromuscular or neuropathic disorder. Patients without palpable pulses should be further evaluated with vascular studies, especially if surgery is being considered.

AP, lateral, and oblique standing radiographs of the foot are routinely performed to evaluate the hindfoot. Weight-bearing radiographs accurately assess alignment and the degree of degenerative joint changes. The AP view will reveal any arthritic change as well as forefoot adduction or abduction through the TN joint. Talar head uncovering is frequently used to indicate the amount of abduction present and guide surgical treatment of flatfoot disorder. Arthritis of the CC joint is best seen on an oblique radiograph. The ST and TN joints are well visualized on lateral radiographs, as are any pes planus or cavus deformities.¹⁷ Hindfoot alignment and axillary views are also useful to assess varus or valgus hindfoot deformity¹⁸ (Figure 1).

CT scans provide the most accurate assessment of the hindfoot joints and may be useful in surgical planning. Weight-bearing CT (wbCT) allows radiographic analysis of the hindfoot under physiologic loads. This may be a useful adjunct in measuring hindfoot alignment and aid in surgical decision making and therapeutic planning.^19,20,21 Ultrasonography can effectively identify cortical erosions and synovitis in inflammatory arthritides at low cost and without ionizing radiation exposure. However, ultrasonography’s efficacy is operator-dependent and is not routinely used in the workup for arthritis.²² MRI has high sensitivity for detecting arthritic changes in joints but may not be routine imaging for arthritides. Nuclear medicine studies and magnetic resonance arthrography may not be as clinically useful as CT studies. Both have good sensitivity for disease detection but often do not provide the bony resolution that radiograph-based imaging does.²³

Isolated ST arthritis commonly occurs after intra-articular calcaneal fractures are sustained, but also can be the result of RA, ST coalition, or a long-standing hindfoot
deformity.⁶ Subtalar arthrodesis is typically performed through a lateral approach. The hindfoot should be positioned in approximately 5° of valgus and fixed with one or two screws (Figure 2).

Posttraumatic ST arthritis after calcaneal fracture can pose several additional challenges. A lateral calcaneal wall exostectomy may be required to relieve subfibular impingement. There may also be anterior ankle joint impingement because of loss of calcaneal height, which necessitates distraction arthrodesis. This will restore hindfoot height and talar declination, thereby relieving anterior impingement³⁶ (Figure 3). In a 2008 study, investigators described a posterior approach for ST distraction arthrodesis.³⁷ This approach offers the advantages of avoiding previous surgical incisions, provides excellent ST joint exposure, and is optimal for correcting large varus or valgus deformities in addition to joint distraction.