Calcaneus Fractures

Etiology

Calcaneal fractures most often result from high-energy axial loading of the heel, such as falls from height or motor vehicle collisions, in which the talus wedges into the calcaneus, producing intra-articular or comminuted fractures of the calcaneal body. Lower-energy mechanisms, including twisting injuries, direct blows, or inversion events, can produce extra-articular patterns, such as anterior process, sustentacular, or tuberosity fractures, without the classic burst morphology. Calcaneal stress fractures arise from repetitive submaximal loading that exceeds the bone’s ability to remodel and are seen in runners, military recruits, and patients with risk factors such as osteoporosis, corticosteroid use, or sudden increases in training. These stress injuries include fatigue fractures in normal bone exposed to excessive cyclic loading and insufficiency fractures in weakened bone exposed to normal loading and typically present more subtly than acute, high-energy trauma.[4][5] 

Epidemiology

Calcaneus fractures are the most common fractures of the tarsal bones, accounting for approximately 60% of all tarsal fractures and 1% to 2% of all fractures. They most frequently occur in young, working-age adults, with a peak incidence between 30 and 50 years of age. Men are affected significantly more often than women, largely due to greater occupational and recreational exposure to high-energy trauma. The predominant mechanism of injury is axial loading from falls from height, followed by motor vehicle collisions, making these injuries particularly common among construction workers, roofers, and industrial laborers. Approximately 70% to 75% of calcaneal fractures are intra-articular, involving the posterior facet of the subtalar joint, while the remaining fractures are extra-articular.

Because calcaneal fractures typically result from high-energy mechanisms, they are frequently associated with concomitant injuries. Lumbar spine compression fractures, lower extremity fractures, pelvic injuries, and contralateral calcaneal fractures occur in a substantial proportion of patients, necessitating a thorough trauma evaluation. Bilateral calcaneal fractures are reported in approximately 5% to 10% of cases. Smoking, diabetes mellitus, peripheral vascular disease, and obesity are associated with increased complication rates and poorer functional outcomes. Although calcaneal fractures represent a relatively small percentage of all fractures, they account for a disproportionate amount of long-term disability, prolonged work absenteeism, and socioeconomic burden due to persistent pain, post-traumatic arthritis, and limitations in mobility.[6]

Pathophysiology

Calcaneus fractures most commonly result from high-energy axial loading, such as a fall from height or motor vehicle collision, in which compressive forces are transmitted through the talus into the calcaneus. This force causes trabecular and cortical bone failure, frequently resulting in intra-articular fractures involving the posterior facet of the subtalar joint. The degree of fracture comminution and displacement is determined by the magnitude of the applied force, bone quality, and foot position at the time of injury.

Disruption of the subtalar joint alters hindfoot biomechanics, leading to loss of calcaneal height, widening of the heel, decreased Böhler's angle, and increased varus or valgus malalignment. These structural changes impair normal load transmission across the hindfoot and compromise gait mechanics. The initial injury also produces significant soft tissue trauma, edema, and hemorrhage, which contribute to the high rate of wound complications associated with surgical management.

Gunshot wounds and other ballistic injuries produce more unpredictable fracture patterns, although such injuries are uncommon. Avulsion fractures require significant twisting or shearing forces due to the strength of ligamentous and tendinous attachments to the calcaneus. The tibial artery and nerve course along the medial aspect of the calcaneal body and are considered relatively protected by the sustentaculum tali. Therefore, neurovascular injury is uncommon in calcaneal fractures.[7][8]

History and Physical

A thorough history and physical examination are essential for diagnosing calcaneus fractures and identifying associated injuries. Most calcaneal fractures result from high-energy axial loading mechanisms, such as falls from height or motor vehicle collisions, although low-energy mechanisms may occur in patients with osteoporosis or other metabolic bone disorders. Patients typically report immediate onset of severe heel pain, inability or difficulty bearing weight, and substantial swelling following injury. The mechanism of injury should be carefully elicited, as high-energy trauma is frequently associated with concomitant injuries to the lumbar spine, pelvis, lower extremities, and contralateral calcaneus. A complete trauma evaluation and tertiary physical exam is therefore warranted in patients suspected of calcaneus fractures.

The physical examination begins with inspecting the affected foot for swelling, ecchymosis, deformity, and fracture blisters. Plantar ecchymosis extending across the sole (Mondor sign) is highly suggestive of a calcaneal fracture. The heel should be assessed for widening, loss of normal contour, varus or valgus malalignment, and shortening. Palpation typically reveals tenderness over the calcaneal tuberosity, subtalar joint, and lateral wall. Active and passive ankle and subtalar range of motion are often limited because of pain. A comprehensive neurovascular examination should be performed, documenting the posterior tibial and dorsalis pedis pulses and the sensory function of the tibial, sural, superficial peroneal, deep peroneal, and saphenous nerves. The overlying soft tissues require careful assessment, as swelling, blistered fractures, and skin compromise significantly influence treatment timing.

Evaluation differs depending on whether the injury represents a tongue-type or joint depression-type fracture. Tongue-type fractures require urgent identification because the superiorly displaced posterior tuberosity fragment is pulled proximally by the Achilles tendon, creating significant pressure on the thin posterior heel skin. Even minimal skin blanching or tenting constitutes an orthopedic emergency due to the risk of rapid skin necrosis and full-thickness soft-tissue loss. The posterior heel should therefore be inspected meticulously for blanching, threatened skin, or impending ulceration. Immediate plantarflexion splinting may reduce tension on the skin while definitive treatment is arranged.

In contrast, joint depression-type fractures rarely produce posterior skin compromise but typically demonstrate greater disruption of the posterior facet of the subtalar joint. Patients often present with diffuse hindfoot swelling, lateral heel widening, and tenderness over the subtalar joint. Clinical examination should focus on identifying hindfoot malalignment, lateral wall blowout with peroneal tendon impingement, and associated injuries to adjacent joints. Recognition of the fracture pattern during the initial evaluation is critical because tongue-type fractures often require urgent operative intervention to prevent soft-tissue complications, whereas joint-depression-type fractures are generally managed after soft-tissue swelling has sufficiently resolved.

Evaluation

Evaluating a suspected calcaneus fracture begins with a complete neurovascular examination and assessment of lower extremity tendon function. Loss of the ipsilateral dorsalis pedis or posterior tibial pulse compared with the contralateral limb should raise concern for arterial injury and prompt further investigation with angiography or Doppler ultrasonography. Initial radiographic assessment includes anteroposterior, lateral, and oblique views of the foot and ankle (see Image. Lateral Right Ankle Radiograph Exhibiting Calcaneal Fracture). A Harris view may be obtained to demonstrate the calcaneus in axial orientation.[9]

Noncontrast computed tomography (CT) is the gold standard for evaluating traumatic calcaneal injuries, providing detailed characterization for classification and preoperative planning, and is indicated when clinical suspicion remains high despite normal radiographic findings (2-3 mm cuts are recommended). The Mondor sign, representing a plantar hematoma extending along the sole on CT, is considered pathognomonic for a calcaneal fracture. Stress fractures, such as those associated with running, are more appropriately evaluated with bone scintigraphy or magnetic resonance imaging.

The Böhler angle may be decreased on plain radiographs, defined by the angle between a line from the highest point of the tuberosity to the highest point of the posterior facet and a second line from the highest point of the anterior process to the highest point of the posterior facet. Normal values range from 20° to 40°. The critical angle of Gissane may be increased, defined by the angle between a line along the anterior downward slope of the calcaneus and a line along the superior upward slope. Normal values range from 130° to 145°.  A normal Böhler angle and critical angle of Gissane do not exclude the occurrence of a fracture. Abnormalities in either measurement should prompt CT for further fracture classification and evaluation. 

Calcaneal fractures are broadly classified into extra-articular and intra-articular types. Extra-articular fractures account for approximately 25% of cases and typically represent avulsion injuries involving the calcaneal tuberosity at the Achilles tendon insertion, the anterior process at the bifurcate ligament, or the sustentaculum tali. Intra-articular fractures account for the remaining 75% of calcaneal fractures and result from axial loading in which the talus acts as a wedge or hammer, compressing the calcaneus at the angle of Gissane and producing articular disruption.[10][11]

Two principal classification systems are used to describe calcaneal fractures. The Essex-Lopresti classification describes fracture patterns based on axial loading mechanisms and primary fracture lines.[12]

• Joint depression type is characterized by a single vertical fracture line through the angle of Gissane, separating the anterior and posterior portions of the calcaneus (see Image. Intra-articular Calcaneus Fracture with Subtalar Joint Depression).
• Tongue-type demonstrates a similar vertical fracture line, with an additional horizontal fracture line extending posteriorly, resulting in a superior posterior fragment and potential superior rotation of the tuberosity fragment.

The Sanders classification is based on coronal and axial CT findings of the posterior facet.[13]

• Type I fractures: nondisplaced or minimally displaced fractures with a single fracture line
• Type II fractures: 2 fracture fragments of the posterior facet and are subdivided into types A, B, and C based on medial-to-lateral fracture line location
• Type III fractures: 3 posterior facet fragments with a central depressed fragment and are subdivided into types AB, AC, and BC based on fracture line configuration
• Type IV fractures: severely comminuted injuries with 4 or more fracture fragments

Treatment / Management

Initial Management

Initial treatment includes aggressive wound care with antibiotics as indicated for contaminated wounds. Analgesics are administered for pain control. Ice application and elevation are recommended to reduce swelling. Immobilization is typically achieved with splinting, most commonly using bulky Jones-type splints. Patients selected for outpatient management require a strict non–weight-bearing status at discharge.[14]

Treatment of Closed Fractures

Most extra-articular fractures are managed conservatively with 10 to 12 weeks of immobilization in a cast or splint. Calcaneal tuberosity avulsion fractures, displaced sustentaculum tali fractures, and large calcaneal body fractures may require operative management. Selected intra-articular fractures may be managed nonoperatively depending on severity and patient co-morbidities.

Operative management includes open reduction and internal fixation, percutaneous pinning, and, in severe cases, arthrodesis. Nondisplaced Sanders type I fractures are usually treated with closed, conservative management. If contemplated, surgical treatment aims to restore calcaneal height and width by reestablishing calcaneal anatomy, including normalization of the Böhler and Gissane angles and restoration of subtalar joint congruity. Hindfoot mechanical alignment is reconstituted to restore functional biomechanics.

Surgical Management

Surgical intervention is typically recommended for the following indications:

• Displaced tongue-type fractures
• Joint depression fractures with articular comminution or anterior process involvement
• Fractures with the Böhler angle <5° on initial presentation
• Dislocated fractures
• Anterior process fractures involving >25% of the calcaneocuboid articulation
• Calcaneal body fractures with significant varus or valgus malalignment, lateral impingement, loss of calcaneal height, or significant posterior tuberosity translation [15]
(B2)

When surgical management is recommended, the primary goals include restoring calcaneal morphology and reestablishing articular congruency. The decision to proceed with surgery requires fully informed consent, given the substantial risks associated with operative intervention, and should incorporate shared decision-making with the patient. Operative management of calcaneal fractures is associated with a high risk of complications.

Surgical treatment should be delayed until the return of the so-called “wrinkle sign,” typically occurring 5 to 10 days following injury. All serous and hemorrhagic blisters must be fully epithelialized prior to intervention. Sanders et al report that soft tissue swelling may require up to 21 days to resolve, and that surgical intervention should not proceed until adequate soft tissue recovery has occurred.[16](B2)

Treatment of open fractures

Open calcaneal fractures require emergent irrigation, debridement, and meticulous wound management. Outcomes in open calcaneal fractures are generally poorer compared with closed fractures. A 2004 case series by Aldridge et al reviewed outcomes of open calcaneectomy for calcaneal fractures and reported higher-than-expected quality-of-life measures despite a substantial complication rate. Operative treatment was associated with increased complications compared with closed fractures. However, the complication rate observed in the study was lower than previously reported in the literature.[17] Aldridge et al recommended against definitive fixation at the time of initial irrigation and debridement.(B2)

Previous literature by Siebert et al included 36 open calcaneal fractures, with complications including the need for soft tissue coverage in 23 cases, development of osteomyelitis in 9 cases, amputation in 5 cases, and arthrodesis in 1 case. The cohort also demonstrated poor postoperative quality-of-life metrics. The poorest patient-reported outcomes and highest complication rates were observed in Grade III open fractures.[18] Surgical treatment has historically been categorized into 2 main approaches: the open extensile lateral technique and minimally invasive methods. Emerging techniques for primary arthrodesis are also described. Tourniquet use is recommended for all surgical approaches.(B2)

Extensile lateral approach

The extensile lateral technique has served as the primary surgical strategy for the operative management of calcaneal fractures for many years. This approach provides adequate intraoperative visualization and facilitates manipulation of fracture fragments to restore alignment and articular congruity. The extensile lateral approach is performed by creating full-thickness soft-tissue and periosteal flaps, as previously described by Gould and later modified by Benirschke and Sangeorzan.[19] Lateral calcaneal structures and articular surfaces are well visualized using this method. Temporary retraction is typically achieved through placement of Kirschner wires into the talus, fibula, and cuboid.

Fracture lines are opened during this stage and may include temporary removal of the lateral wall. Manual traction is used to restore the height and length of the tuberosity, with placement of a Steinmann pin into the tuberosity to assist in this restoration. Varus deformity requires correction at this stage. Temporary reduction may be maintained through placement of Kirschner wires from the tuberosity fragment into the “constant” fragment of the medial sustentaculum.

The articular surface of the lateral posterior facet requires anatomic reduction under direct visualization and may be stabilized with temporary fixation. Lag screw fixation typically provides compression across the articular surface to facilitate healing, as described by Sanders et al. Care is required to avoid overpenetration of the medial cortex, particularly of the constant fragment, which may result in flexor hallucis longus tendon entrapment and fixed hallux flexion.

Reduction and alignment should be confirmed with fluoroscopy prior to exchange for definitive fixation. Wound closure is performed in layers, with many authors recommending drain placement. Closure is commonly performed using an interrupted Allgöwer–Donati suture to reduce tension across the incision. Level I evidence supports the use of the Allgöwer–Donati suture over the vertical mattress technique in lower extremity trauma, with improved tissue perfusion at the incision site.[20] A recent meta-analysis also demonstrated reduced suture time and drainage duration, without an increased risk of complications, compared with vertical mattress closure.[21](A1)

Minimally invasive approach 

The goals of the minimally invasive technique, also known as the sinus tarsi approach, include minimizing soft tissue injury while allowing fracture reduction and stabilization. Indications include Sanders types II and III fractures, comorbidities that increase soft tissue complication risk, such as diabetes mellitus, smoking, obesity, and peripheral vascular disease, and fractures with minimal posterior facet comminution. The sinus tarsi approach is performed through a 2- to 4-cm incision along a line from the tip of the fibula toward the base of the fourth metatarsal, allowing direct visualization of the posterior facet and anterolateral fragment of the lateral wall.

A low-profile plate is typically used following reduction of the joint surface and is positioned along the joint line. Adjunctive percutaneous screws are often placed to restore calcaneal morphology, including height, width, and hindfoot alignment. A Schanz pin is inserted through a percutaneous incision to facilitate manipulation of the calcaneal tuberosity. Alignment is assessed intraoperatively under fluoroscopy.

Absence of an extensile L-shaped flap reduces the risk of fibular (peroneal) tendon irritation and sural nerve complications. The same incision may be utilized for subsequent subtalar arthrodesis if required.[22] Some authors contend that anatomic reduction, fracture disimpaction, and fracture repositioning are more difficult to achieve with limited exposures. Conversion to an extensile lateral approach is generally not recommended once a minimally invasive approach is selected, underscoring the need for careful preoperative selection of the appropriate surgical approach for each patient.(B3)

A recent meta-analysis compared minimally invasive techniques with the standard extensile lateral approach. The analysis included 2179 participants with a mean follow-up of 22.41 months. No statistically significant differences were observed in postoperative calcaneal width, calcaneal length, deep infection rates, or Gissane angle between approaches. Differences favoring minimally invasive techniques were observed in wound complications, superficial infection, nerve injury, Visual Analog Scale (VAS) pain scores, American Orthopaedic Foot and Ankle Society (AOFAS) scores, calcaneal height, and postoperative Böhler's angle.

Findings contribute to the growing body of evidence supporting smaller incision techniques in selected patient populations.[23] No comparison of preoperative fracture morphology was included, and many authors note that more severe fracture patterns often require extensile approaches and are associated with higher complication rates regardless of technique. Kline et al retrospectively reviewed a cohort of 112 calcaneal fractures, with 79 treated using the extensile lateral approach and 33 managed with minimally invasive techniques.(A1)

Allocation was based on surgeon preference; group demographics were comparable. The extensile lateral group included 53% Sanders type II fractures and 47% Sanders type III fractures. The minimally invasive group included 61% Sanders type II fractures and 39% Sanders type III fractures. Both groups demonstrated a 100% union rate and similar radiographic outcomes with respect to Böhler's angle and the Gissane critical angle. The wound complication rate was 29% in the extensile lateral group, with 9% of total cases requiring reoperation for complications. The minimally invasive group demonstrated a 6% wound complication rate, with no cases requiring additional surgery.

Kline et al concluded that minimally invasive techniques may reduce complication rates while maintaining comparable radiographic outcomes.[24] Similar findings have been reported in other studies, suggesting that the sinus tarsi approach achieves comparable radiographic and functional outcomes with fewer overall wound complications.[25] Some caution is warranted with this approach.(A1)

As with many orthopedic techniques, a defined learning curve exists for the sinus tarsi approach. Results from a study of 66 calcaneal fractures at a level I trauma center demonstrated a 29% reduction in surgical complications per year of surgeon experience and an approximately 9% reduction in complications per case. The likelihood of achieving good or excellent radiographic reduction also increased significantly with each additional year and each additional case performed by the surgeon.[26]

Primary arthrodesis

Displaced intra-articular calcaneal fractures carry a high risk of posttraumatic arthritis. Open arthrodesis for Sanders types III and IV fractures has demonstrated favorable outcomes in terms of return-to-work rates and fusion rates. To minimize the risk of wound complications, techniques such as percutaneous reduction combined with posterior subtalar arthrodesis have demonstrated high fusion rates with low complication rates, while still allowing restoration of calcaneal morphology.[27] Another study using a sinus tarsi approach similarly reported high fusion rates and a relatively high return-to-work rate in a workers’ compensation population.[28]

Special Cases

Certain calcaneal fracture patterns require deviation from standard treatment algorithms due to unique biomechanical or soft tissue considerations. These special cases necessitate individualized management strategies based on fracture morphology and associated risk factors. Key examples are explained below.  

Severely displaced closed calcaneal fractures with heel varus deformity

Some authors have adopted a 2-stage surgical approach for severely displaced closed calcaneal fractures to mitigate soft tissue compromise. Fracture displacement and loss of the Böhler angle result in a shortened and widened calcaneus with associated heel varus deformity. A small series by Githens et al evaluated medial external fixator placement to improve soft-tissue healing, facilitate early restoration of calcaneal morphology, and reduce wound-related complications by retensioning the soft-tissue envelope during operative management.

The series included 21 fractures and demonstrated restoration of calcaneal length, height, and axial alignment with external fixation. The Böhler angle was not reliably restored with external fixation and ligamentotaxis alone. No deep or superficial wound infections requiring surgical intervention were reported, although the authors cautioned against drawing definitive conclusions given the small sample size, limited statistical power, and absence of a control group.

Tongue-type fractures

Tongue-type fractures produce variable displacement of the calcaneal tuberosity fragment. Achilles tendon traction may result in significant superior and dorsal displacement, with posterior heel skin tenting and an increased risk of soft-tissue breakdown. Emergent reduction is recommended to relieve skin tenting. Temporizing management typically includes a removable posterior splint in plantarflexion with close skin monitoring until definitive treatment.

Delayed reduction may result in skin breakdown with severe sequelae. Urgent fracture reduction should be performed at the first sign of skin compromise. A review of 139 tongue-type fractures at a single institution over a 5-year period reported a 21% rate of soft tissue compromise, with a higher risk associated with greater initial displacement. No subsequent soft-tissue complications were reported among patients with threatened soft tissue at presentation who underwent emergent operative reduction and fixation.[29](B2)

Severely comminuted fractures

Some surgeons favor primary subtalar arthrodesis, as it may reduce the need for subsequent procedures, associated costs, and time away from work.[30] However, other studies have demonstrated that patients who develop posttraumatic arthritis after initial open reduction and internal fixation with intraoperative restoration of calcaneal morphology may experience improved outcomes compared to patients who develop subtalar arthritis secondary to malunion following nonoperative management.[31](A1)

Differential Diagnosis

Differential diagnosis of calcaneal fractures includes severe ankle sprain, Achilles tendon rupture, talar fractures, subtalar dislocation, and calcaneocuboid joint injury. Stress fractures of the calcaneus may mimic overuse injuries, such as plantar fasciitis or heel contusion. Clinical overlap with soft tissue injuries and subtalar pathology may delay diagnosis without appropriate imaging evaluation.

Prognosis

A recent randomized controlled trial evaluated operative versus nonoperative treatment of closed, displaced intra-articular calcaneus fractures. The study included 151 patients, with 73 assigned to the operative arm and 78 assigned to the nonoperative arm. The operative group underwent treatment using the extensile lateral approach (see Extensile lateral approach). The nonoperative group received initial immobilization followed by gentle mobilization as tolerated.

Results demonstrated a higher complication rate in the operative group, including infection and hardware removal in 11% of patients. No significant differences in health outcomes, range of motion, heel width, walking speed, or gait parameters were observed between groups. Recovery was prolonged in both groups, with most functional improvement plateauing at approximately 18 months. Persistent adverse effects were reported by most participants at 2 years. The study concluded with recommendations against operative intervention for closed, displaced intra-articular calcaneus fractures.[32]

A 2017 meta-analysis that included 18 trials involving 1467 patients demonstrated significantly improved anatomic outcomes with operative management, including restoration of the Böhler angle, calcaneal height, and calcaneal width, as well as a higher likelihood of return to work. The analysis confirmed a higher complication rate associated with operative intervention. Operative treatment of displaced intra-articular calcaneal fractures was associated with improved anatomic restoration, functional outcomes, and return-to-work rates.[33]

The Sanders classification demonstrates sustained prognostic value. A cohort of 108 operatively treated calcaneal fractures (Sanders types II and III) was evaluated at a minimum of 10 years, with a mean follow-up of 15.22 years. Postoperative CT imaging demonstrated anatomic posterior facet reduction in 95% of fractures, with no articular step-off and no reductions exceeding 5 mm of malalignment. Within this cohort of well-reduced fractures, Sanders type III fractures were 4 times more likely to require subsequent subtalar arthrodesis compared with type II fractures. Long-term functional outcomes included mild pain and persistent limitations in activities of daily living.

Certain populations demonstrate more favorable outcomes. These groups include women, younger adults, patients engaged in occupations involving lower physical workloads, and individuals without workers’ compensation claims. A higher initial Böhler angle is also associated with improved outcomes, with a Böhler angle less than 0° correlating with poorer functional results. A Böhler angle greater than 15° at presentation is associated with improved functional outcomes regardless of operative or nonoperative treatment.[34] Several factors have been identified as predictors of poorer functional outcomes, including polytrauma, alcohol abuse, psychiatric illness, unemployment at the time of injury, and the development of posttraumatic osteoarthritis.[35]

Complications

Concomitant injuries must be considered during clinical assessment due to the severe nature and high-energy mechanisms required to sustain calcaneal fractures.[36][37] Studies demonstrate that an estimated 70% of patients with calcaneal fractures present with additional injuries. A thorough evaluation of the entire spine should be performed whenever a calcaneal fracture is identified, particularly in cases involving falls from height.

Impact forces transmit through the lower extremity and into the axial skeleton, occasionally resulting in vertebral fractures. Compartment syndrome of the foot is a rare but severe complication of calcaneal fractures and may occur in up to 10% of cases. A high index of suspicion is required in patients presenting with escalating pain during initial assessment or following treatment.

Osteomyelitis, postoperative wound infection, malunion, and subtalar arthritis are potential complications following calcaneal fractures and their surgical management. Infection and wound breakdown are the most common and clinically significant complications associated with the extensile lateral approach. Reported rates of wound complications and infection reach up to 37% and 20%, respectively, following operative intervention.[38]

Subtalar osteoarthritis may develop following either surgical or nonsurgical treatment, with an increasing proportion of patients with nonoperatively managed displaced intra-articular calcaneal fractures requiring delayed subtalar fusion due to progressive subtalar arthritis. Another study demonstrated that nonoperative management was up to 6 times more likely to result in late subtalar fusion secondary to symptomatic subtalar arthritis.[39] This condition represents posttraumatic arthritis. Loss of subtalar motion is also common following a calcaneal fracture.

Sural nerve injury occurs in up to 15% of operatively treated cases and is more commonly associated with the extensile lateral approach. Risk reduction has been reported with the use of a more inferiorly based L-shaped incision.[40] Chronic pain is another frequent complication, often related to posttraumatic subtalar arthritis, malalignment, or stiffness following injury.

Peroneal tendon instability may result from displaced intra-articular calcaneal fractures.[41] Mechanisms include direct tendon injury or impingement by displaced fracture fragments. Up to 40% displacement of the peroneal tendons has been reported on CT imaging in calcaneal fractures.[42] A more recent CT-based study further evaluated the prevalence of peroneal tendon instability.

Assessment included fracture morphology, associated lateral malleolar fracture, tendon dislocation, calcaneal wall displacement, fracture-dislocation, superior fibular retinacular avulsion (fleck sign), and retromalleolar groove morphology. Imaging findings were compared with intraoperative stress testing of the superior peroneal retinaculum to determine the presence of true instability. The study's results reported a 16.7% rate of instability, with calcaneal fracture-dislocation identified as the only preoperative CT factor significantly associated with instability (99.1%).[43]

Furthermore, significant calcaneal height loss, widening, and hindfoot varus may result in subfibular impingement due to osseous or soft tissue abnormalities. Subfibular impingement may present as lateral heel pain, particularly with hindfoot eversion. Techniques have been described involving percutaneous calcaneal osteotomy and fibular tendon decompression to address subfibular impingement following calcaneal malunion.[44]