Intraarticular Calcaneus Fractures: Comprehensive Surgical Management

INTRAARTICULAR FRACTURES OF THE CALCANEUS: AN OVERVIEW

The management of intraarticular calcaneus fractures remains one of the most debated and challenging topics in orthopaedic trauma. Extensive studies evaluating fracture patterns, soft tissue management, and long-term outcomes have provided a clearer understanding of which injuries benefit from early surgical intervention and which are predisposed to high complication rates.

Regardless of the chosen treatment modality—operative or non-operative—calcaneal fractures are notoriously associated with numerous complications and suboptimal outcomes, leading to significant long-term quality-of-life (QOL) issues. Validated outcome measures (such as the SF-36) have demonstrated that outcomes in patients with displaced intraarticular calcaneal fractures are often inferior to those of patients with other severe orthopaedic conditions. Strikingly, these outcomes have been shown to be significantly worse than those of patients recovering from other major systemic health crises, including myocardial infarctions and solid organ transplants.

Clinical Pearl: Patient counseling is paramount. Patients with calcaneal fractures must be explicitly informed of the potential life-changing nature of this injury. This is especially critical for laborers or individuals whose occupations require prolonged standing or walking. The surgeon must set realistic expectations regarding the prolonged recovery time (often 12 to 18 months) and the high likelihood of residual stiffness, chronic pain, or the eventual need for a subtalar arthrodesis.

MECHANISM OF INJURY AND BIOMECHANICS

Intraarticular fractures account for approximately 75% of all calcaneal fractures and have historically been associated with poor functional outcomes due to the disruption of the complex subtalar joint mechanics.

The Axial Load Mechanism

These fractures are almost uniformly caused by a high-energy axial load mechanism, most commonly a fall from a height or a high-speed motor vehicle collision. Because the force is transmitted vertically through the skeletal axis, calcaneus fractures are frequently associated with other axial load injuries.

Surgical Warning: Always maintain a high index of suspicion for concomitant injuries. Approximately 10% of patients with a calcaneus fracture will have an associated lumbar spine fracture (often a burst fracture), and 10% will have a contralateral calcaneus fracture. Pelvic ring disruptions and tibial plateau fractures must also be ruled out during the secondary ATLS survey.

Biomechanics of the Fracture Pattern

Cadaveric studies, detailed anatomical dissections, and the routine use of multi-planar Computed Tomography (CT) have allowed for a highly detailed description of the mechanism of injury and the resulting predictable fracture patterns.

The biomechanical genesis of the fracture is dictated by the anatomical alignment of the hindfoot. The contact point of the calcaneus (the tuberosity) is situated slightly lateral to the primary weight-bearing axis of the lower extremity. As an immense axial load force is applied, the talus acts as a wedge. The lateral process of the talus is driven directly into the crucial angle of Gissane.

Because of the lateral offset, shear forces are directed obliquely through the posterior facet of the calcaneus toward the medial wall.

Pathoanatomy: Primary and Secondary Fracture Lines

The ensuing primary fracture line is almost always present and is created by shear forces. It extends from the proximal-medial aspect of the calcaneal tuberosity, propagating diagonally through the anterolateral wall, usually exiting in the vicinity of the crucial angle of Gissane.

This primary shear line effectively divides the calcaneus into two main fragments:
1. The Anteromedial Fragment (The "Constant" Fragment): This includes the sustentaculum tali. It is termed the "constant" fragment because it remains firmly tethered to the talus via the robust interosseous talocalcaneal ligament and the deltoid ligament complex. It rarely displaces from its anatomical position relative to the talus.
2. The Posterolateral Fragment (The Tuberosity Fragment): This fragment contains the lateral portion of the posterior facet and the calcaneal tuberosity. Due to the pull of the Achilles tendon, this fragment typically displaces proximally, superiorly, and into varus, resulting in the classic shortened, widened, and flattened heel.

The most variable aspect of this primary fracture line is its exact position as it traverses the posterior facet, which forms the basis of the Sanders CT classification.

Following the primary shear fracture, continued axial loading produces secondary fracture lines via compression. These secondary lines dictate whether the fracture becomes a "joint depression" type (where the articular segment is driven into the cancellous body of the calcaneus) or a "tongue-type" fracture (where the secondary line exits posteriorly through the tuberosity).

CLINICAL EVALUATION AND IMAGING

Soft Tissue Assessment

The timing and success of surgical intervention are entirely dictated by the soft tissue envelope. Calcaneus fractures result in massive hindfoot swelling.

• Fracture Blisters: Hemorrhagic and clear fracture blisters are common. Surgery through hemorrhagic blisters carries an unacceptably high risk of deep infection and flap necrosis.
• The Wrinkle Test: Operative intervention must be delayed until the soft tissues allow for skin wrinkling upon dorsiflexion and eversion of the foot. This typically takes 10 to 14 days post-injury.
• Compartment Syndrome: The foot contains nine distinct fascial compartments. Tense swelling, disproportionate pain, and clawing of the toes require immediate evaluation for foot compartment syndrome, which may necessitate fasciotomy.

Radiographic Evaluation

Standard radiographic evaluation includes:
* Lateral View: Assesses the depression of the posterior facet.
* Böhler’s Angle: Normally 20° to 40°. A decreased or negative angle indicates collapse of the posterior facet and loss of calcaneal height.
* Angle of Gissane: Normally 130° to 145°. An increase indicates disruption of the posterior facet.
* Harris Axial View: Evaluates heel width, varus deformity of the tuberosity, and the primary fracture line.
* AP and Oblique Views of the Foot: Assesses the calcaneocuboid joint and the anterior process.

Computed Tomography (CT)

A fine-cut CT scan (axial, coronal, and sagittal planes) is the gold standard for preoperative planning.
* Coronal Images: Essential for evaluating the posterior facet and applying the Sanders Classification (Types I-IV), which is based on the number and location of articular fracture lines at the widest portion of the posterior facet.
* Axial Images: Best for evaluating the calcaneocuboid joint and the sustentaculum tali.
* Sagittal Images: Excellent for assessing tuberosity displacement and the overall length and height of the calcaneus.

SURGICAL MANAGEMENT: INDICATIONS AND APPROACHES

Indications for Surgery

The goal of surgery is to restore calcaneal height, length, and width, correct varus malalignment, and anatomically reduce the subtalar joint.
* Displaced intraarticular fractures (>2 mm step-off).
* Loss of Böhler’s angle (flattening of the heel).
* Significant widening of the heel (which can cause lateral impingement against the fibula).
* Varus deformity of the tuberosity.
* Tongue-type fractures with skin compromise posteriorly (requires emergent reduction).

The Extensile Lateral Approach

The extensile lateral approach remains the workhorse for complex, displaced intraarticular calcaneus fractures (Sanders II, III, and select IV).

1. Positioning and Preparation:
The patient is placed in the lateral decubitus position on a radiolucent table. A bean bag is used for stabilization. All bony prominences are padded. A thigh tourniquet is applied. The fluoroscopy machine is positioned to allow for unhindered lateral, axial, and Broden's views.

2. The Incision:
An L-shaped incision is utilized. The vertical limb is placed just anterior to the Achilles tendon, and the horizontal limb is placed in line with the base of the fifth metatarsal, ensuring it is at the junction of the dorsal and plantar skin (the glabrous junction) to protect the sural nerve and the vascular supply of the flap.

Surgical Warning: The lateral flap receives its blood supply from the lateral calcaneal artery. The flap must be elevated as a single, full-thickness "no-touch" subperiosteal layer. Retractors should not be placed directly on the skin edges. Instead, 1.6 mm K-wires are driven into the talus, fibula, and cuboid to retract the flap gently.

3. Step-by-Step Reduction Sequence:
* Step 1: Tuberosity Reduction. A 5.0 mm Schanz pin is placed transversely into the posteroinferior aspect of the calcaneal tuberosity. Using the pin as a joystick, the tuberosity is pulled out of varus, translated medially, and pulled plantarly and posteriorly to restore calcaneal length, height, and alignment. This is provisionally pinned to the "constant" sustentacular fragment.
* Step 2: Articular Reduction. The depressed posterior facet fragments are elevated out of the cancellous bone void. They are anatomically reduced to the sustentaculum tali and provisionally fixed with subchondral K-wires.
* Step 3: Anterior Process Reduction. The calcaneocuboid joint and anterior process are reduced and pinned.
* Step 4: Lateral Wall Neutralization. The lateral wall blowout is reduced to restore the normal width of the calcaneus, preventing subfibular impingement.

4. Fixation Strategy:
Once fluoroscopy confirms anatomical reduction of the posterior facet (via Broden's views) and restoration of Böhler's angle and heel width, definitive fixation is applied. A low-profile, anatomically contoured perimeter plate is placed over the lateral wall. Screws are directed from lateral to medial, ensuring purchase in the dense bone of the sustentaculum tali.

5. Closure:
Closure is meticulous. A deep drain is often placed. The subcutaneous layer is closed with inverted absorbable sutures, and the skin is closed using the modified Allgöwer-Donati technique to minimize tension on the epidermal edges of the flap.

Minimally Invasive Approaches (Sinus Tarsi Approach)

For less complex fracture patterns (e.g., Sanders Type II), the sinus tarsi approach has gained significant popularity. This approach utilizes a small incision directly over the sinus tarsi, allowing direct visualization of the posterior facet while drastically reducing the risk of wound complications. Reduction is achieved percutaneously, and fixation is performed with screws or small specialized plates.

POSTOPERATIVE PROTOCOL AND REHABILITATION

The postoperative rehabilitation protocol is critical to achieving a functional outcome and preventing complications.

• 0 to 2 Weeks: The foot is placed in a bulky Jones dressing and a well-padded posterior splint in neutral dorsiflexion. Strict elevation is mandatory to prevent wound dehiscence.
• 2 to 6 Weeks: Sutures are removed at 2 to 3 weeks once the wound is completely healed. The patient is transitioned to a removable CAM boot. Early, active range of motion (ROM) exercises for the ankle and subtalar joints are initiated to prevent arthrofibrosis. Strict non-weight-bearing (NWB) is maintained.
• 6 to 10 Weeks: NWB continues. Aggressive active and active-assisted ROM.
• 10 to 12 Weeks: Radiographs are obtained to confirm clinical and radiographic union. Progressive weight-bearing is initiated, transitioning from partial to full weight-bearing over a 4-week period.

COMPLICATIONS AND SALVAGE PROCEDURES

Despite meticulous surgical technique, complications remain prevalent.

• Wound Healing Complications: The most feared early complication, occurring in 10-25% of extensile lateral approaches. Minor dehiscence is managed with local wound care; deep infection or flap necrosis may require serial debridements, hardware removal, and free tissue transfer.
• Post-Traumatic Subtalar Arthritis: Occurs due to initial cartilage damage or imperfect reduction. Patients present with chronic lateral hindfoot pain exacerbated by walking on uneven ground. Management begins with orthotics and injections; definitive treatment is a subtalar arthrodesis.
• Malunion: Non-operative management or loss of surgical reduction can lead to a calcaneal malunion characterized by a shortened, widened heel, loss of dorsiflexion (due to anterior ankle impingement), and subfibular impingement. Salvage requires a complex lateral wall exostectomy and corrective subtalar arthrodesis.
• Sural Nerve Injury: Can occur during the initial trauma or iatrogenically during the surgical approach, leading to painful neuromas or lateral foot numbness.

Clinical Pearl: When counseling patients postoperatively, emphasize that maximum medical improvement following an intraarticular calcaneus fracture is rarely achieved before 18 to 24 months. A multidisciplinary approach involving physical therapy, orthotics, and pain management is essential for optimizing the final functional outcome.