Calcaneal fractures

                                Calcaneal fractures

                                                 Dr KS Dhillon

Anatomy

The calcaneus also known as os calcis is the largest of the tarsal bones. It is situated at the back of the foot and it transmits the body weight from the body to the ground. It gives attachment to the muscles of the calf at its posterior aspect. It is cuboidal in shape and has its long axis directed forward and lateralward. It has six surfaces, three of which are articular.

On the anterior part of the superior surface there is an oval shaped articular facet called the posterior articular surface which articulates with the posterior calcaneal facet on the undersurface of the talus. Anterior to the posterior articular surface is the middle articular surface which articulates with the middle calcaneal facet on the under surface of the talus. On the anterior part of the calcaneus there is the anterior articular surface which articulates with the anterior calcaneal facet on the talus.

The posterior part of superior surface is nonarticular and is convex from side to side, concave from before backward, and on it sits a mass of fat which lies in front of the tendoachilles.

The inferior surface of the calcaneus is non articular and it is wider behind and convex from side to side. Posteriorly it is bounded by a transverse elevation called the calcaneal tuberosity. It has a lateral process which  gives origin to part of the Abductor digiti quinti and a the medial process which gives attachment to the Abductor hallucis, the Flexor digitorum brevis and the plantar aponeurosis.

The lateral surface is nonarticular, flat, broad behind and narrow in front,  and almost subcutaneous. At the centre is a tubercle which gives  attachment of the calcaneofibular ligament. Anteriorly on the upper part the  lateral talocalcaneal ligament is attached. In front of the tubercle are two groves. The superior groove transmits the tendon of the Peroneal brevis tendon and the inferior groove transmits the Peroneal longus tendon.

The medial surface of the calcaneus is concave and is directed obliquely downward and forward along which run the plantar vessels and nerves from the leg to the sole of the foot. At the upper and distal part there is a horizontal eminence called the sustentaculum tali which gives attachment to a slip of the tibialis posterior tendon. The eminence is concave above and articulates with the talus. Below it is grooved through which passes the tendon of flexor hallucis longus. The medial surface gives origin to part of the Quadratus plantæ.It also gives attachment to the plantar calcaneonavicular ligament and to part of the deltoid ligament.

Anteriorly it somewhat triangular in form and articulates with cuboid. The medial border gives attachment to the plantar calcaneonavicular ligament.
 
The posterior surface is convex and is wider below than above. It can be divided into three areas. The middle part gives attachment to the tendo achilles and the plantaris. The lowest portion is covered by fibrous fatty tissue of the heel while the upper portion is covered by a bursa which intervenes between it and the tendo achilles.

Epidemiology

Calcaneus is the most common tarsal bone to fracture. Calcaneal fractures account for about 1% to 2% of all fractures [1]. About 17% of the fractures are open fractures.

Mechanism of Injury, Fracture Type, and Classification

The fractures result from, traumatic axial loading following a fall from a height and from motor-vehicle accidents. Calcaneal fractures are broadly divided into two categories namely the extraarticular and intraarticular fractures. About 75% of the fractures are intraarticular.

Intraarticular Fractures

Intraarticular fractures result from axial loading, which produces shear and compression fracture lines [2]. The shear fracture occurs in the sagittal plane and traverses the posterior facet splitting the calcaneus into an anteromedial or sustentacular fragment and a posterolateral or tuberosity fragment [3]. The articulation of the posterior facet with the talus is usually maintained medially because of the medial talocalcaneal and interosseous ligaments. The lateral fragment is angulated (dislocated) laterally and remains impacted leading to a step in the posterior facet. The talus sometimes continues to impact on the lateral edge of the medial fragment and this creates a “double split” in the calcaneus resulting in a middle fragment.

The compression fracture line is usually produced when the anterolateral process of the talus wedges into the angle of Gissane. The fracture runs through the coronal plane and it can extend medially to split the middle facet as well as the anteromedial fragment. Viewed from the side a compression fracture looks like a an inverted “Y,” where the posterior limb runs horizontally towards the tuberosity as a “tongue type” fracture or it runs more vertically, just posterior to the posterior facet, as a “joint depression type” fracture [4]

Classification and treatment of Intraarticular fractures

There are several classifications for intraarticular fractures but the most commonly used is the one by Sanders. For this classification sagittal reconstructed CT images which are parallel and perpendicular to the posterior facet of the subtalar joint are necessary [5,6,7].

The type I fractures are nondisplaced. In type II fractures there are two articular pieces involving the posterior facet. The type II fractures are further divided into types A, B, and C, depending on the location of the fracture line from the lateral to medial side. In type III fractures there are three articular pieces with a depressed middle fragment and are divided into types AB, AC, and BC, depending on the location of the of the fracture lines. In type IV fractures there may be four or more articular fragments with high degree of comminution.  The Sanders classification has been found to be useful in clinical practice [8]. It is not only useful in treatment planning but also useful in determining prognosis [5].

Undisplaced fractures are treated conservatively. Type II fractures treated surgically can yield excellent to good results in about 73% of the patients and in type III fractures the results can be good to excellent in about 70% of the patients [5].

Vasukutty et al [9] did a retrospective review of 80 intra-articular calcaneal fractures treated with open reduction and internal fixation. Internal fixation was carried out through the lateral approach and the fractures were fixed with plates. Clinical and radiological evaluation was carried out. There were 3 open fractures. The mean follow-up was 72 months (range 12 - 130 months). The mean age of the patients was 49 years (range 17 to  73 years). The mean Bohler’s angle improved to 26 degrees post-operatively from 6° preoperatively. The mean foot and ankle disability index score was 78.62, the mean SF-36® scores were 45.5 for the physical component and 52.6 for the mental component. The mean time to return to work in this study was 5.5 months.

Twelve patients (15%) developed symptomatic subtalar joint osteoarthritis. Four (5%) of these patients underwent subtalar fusion.

Classification and treatment of extraarticular Fractures

About 25% to 30% of calcaneal fractures are extraarticular. All calcaneal fractures that do not involve the posterior facet are included in this category.

Extraarticular calcaneal fractures are divided into 3 categories [10]:

(a) Avulsion fracture of anterior process by bifurcate ligament

(b) Fractures of the mid calcaneus including the body, sustentaculum tali,
peroneal tubercle, and lateral calcaneal process

(c) Avulsion fractures of the posterior calcaneus including the tuberosity and medial calcaneal tubercle

The extraarticular fractures can be treated conservative if they are undisplaced or minimally displaced. Depending on the type and location of the fracture, plating, wiring or screw fixation can be the treatment options.

Imaging for calcaneal fractures

Radiographs

Three views of plain radiographs namely the AP, lateral and oblique views are usually recommended for diagnosis of calcaneal fractures.

There are 3 optional views of plain radiographs which can be carried out depending on the circumstances. These include:

• Broden view which allows visualization of posterior facet. It is useful for evaluation of intraoperative reduction of posterior facet. The x ray is done with the ankle in neutral dorsiflexion and about 45 degrees internal rotation. The films are obtained at 10, 20, 30, and 40 deg. of cephalic tilt.
• Harris view demonstrates the body of the calcaneus, middle facet of the subtalar Joint and the sustentaculum tali. It helps visualize tuberosity fragment widening, shortening, and varus positioning. The foot is placed in maximal dorsiflexion and the x-ray beam is angled at 45 degrees.
• AP (dorsoplantar) ankle view demonstrates lateral wall extrusion causing fibular impingement, delineates calcaneocuboid joint and demonstrates subluxation of talonavicular joint.

The lateral view is useful for measurement of the bohler’s angle and the angle of Gissane. The Bohler’s angle is formed by a line drawn from the highest point of the anterior facet to the highest point of the posterior facet and a line tangential to the superior edge of the tuberosity.

The angle is normally between 20 to 40 degrees. A decrease in Bohler’s angle represents a collapse of the posterior facet. The Bohler's angle has significant prognostic value in terms of predicting morbidity. A study by Loucks and Buckley [11] showed that fractures with markedly diminished Bohler's angle have a much poorer two-year outcome regardless of the type of treatment. Hence the initial Bohler's angle is highly prognostic, regardless of treatment modality.

The Gissane (crucial) angle is formed by the downward and upward slopes of the calcaneal superior surface. The normal value for this angle is between 120 to 145 degrees. An increase of this angle represents a collapse of posterior facet.

CT Scans

CT scans of the calcaneus are a must in the management of calcaneal fractures. A 30-degree semi coronal view demonstrates posterior and middle facet displacement. The axial view will demonstrate the involvement of the calcaneocuboid joint and a sagittal view will demonstrate any displacement of the tuberosity.

Complications

Some of the complications associated with calcaneal fractures include:

• Wound complications occur in 10% to 25% of the patients. The incidence is higher in smokers, diabetics, and in patients with open injuries
• Subtalar arthritis. The incidence of posttraumatic OA is about 15% [9]. The incidence is higher with nonoperative management of calcaneal fractures. The incidence of subtalar arthrodesis for symptomatic subtalar OA is 3.3% in patients who had operative treatment of the fracture and about 16.9% in patient who were treated nonoperatively [12].
• Lateral impingement with irritation of peroneal tendon.
• Flexor hallucis longus can be damaged by placement of lateral to medial screws especially at level of sustentaculum tali.
• Compartment syndrome. The incidence of compartment syndrome after calcaneal fractures is between 1% to 10% [13]. 
• Malunion. The Zwipp and Rammelt classification of calcaneal malunion is useful for management of malunions. It includes five types. Type I is characterised by subtalar incongruence with arthritis and a normal shaped calcaneus. In type II malunions there is additional heel varus or valgus. In type III malunions there is additional loss of hindfoot height and in type IV there is in addition translation of calcaneal tuberosity without varus or valgus. In type V malunions there is in addition talar tilt. Symptomatic type I malunions are treated with an in situ subtalar fusion. Type II and type III by bone block fusion and an osteotomy of the calcaneus. Type IV malunions are treated by oblique calcaneal osteotomy and subtalar fusion. Type V malunions are treated by bone block fusion and osteotomy.

Outcome of treatment of calcaneal fractures

Large series of good to excellent results after surgery of intraarticular calcaneal fractures have been published [5,14,15]. Most of the authors, however, compared their results to historical data and used different outcome measures. Furthermore, complications after surgery were not infrequent, and some of the complications were serious.

A few prospective randomized trials which compared surgical with nonsurgical treatment have been published in the past [16,17]. Randle et al [18] did a meta analysis to compare surgical versus nonsurgical treatment for calcaneal fractures. They found six articles which were suitable for the review. There was a tendency towards better outcome with surgical treatment but they could not find sufficient evidence to argue that operative treatment should be recommended for displaced intra articular fractures of the calcaneum.

Buckley et al [12] published a prospective randomized trial in 2002 with over 300 patients which showed that there were no differences in outcome between patients treated operatively and those treated nonoperatively. They were however able to identify subgroups of patients who might benefit from surgery.

Westphal et al [19] compared the general health of 71 patients who had surgical treatment of calcaneal fractures, 2.5 years after injury, with the  general health of 71 people from  the general population, using the SF-36 form. They compared the results of the examination with results of AOFAS Ankle Hindfoot Scale and Maryland Foot Score in the treated patients. They found significant limitations regarding general health in all 9 elements of the SF-36 form, in patients with calcaneal fractures. They concluded that patients with calcaneal fractures have significant limitations regarding general health.

In 2013 Veltman et al [20] carried out a systematic review of the literature to evaluate the long-term outcomes of 1,730 calcaneal fractures. They studied the functional and subjective outcome as well as did a radiographic evaluation at minimum of 2 years after either surgical or conservative treatment of calcaneal fractures. Their findings from the review supported the current clinical practice of treating displaced calcaneal fractures with open reduction and internal fixation.

Conclusion

Calcaneus is the largest of the tarsal bones and is the most frequent of the tarsal bones to fracture. The most common cause for the fracture is  high-energy trauma which causes axial loading. About 75% of the fractures are intra-articular.  Conventional x rays should include anteroposterior, axial, lateral and oblique views. CT scans are essential for classification and management of these fractures. There appears to be no consensus on conservative or surgical treatment of calcaneal fractures. Neither is there a consensus about the operative technique in treatment of calcaneal fractures. The treatment will depend on factors such as type of trauma, the type of fracture and condition of the skin.
The treatment options include no treatment, conservative treatment, open reduction, internal fixation, primary subtalar arthrodesis and a delayed primary arthrodesis.

Complications are common and include infections in about 10% to 25% of the patients, subtalar arthritis in about 15% of the patients and  compartment syndrome in about 1% to 10% of the patients. Other complications include lateral impingement and injury to the flexor hallucis longus. Malunions are common and their treatment include calcaneal osteotomies and subtalar arthrodesis. The incidence of subtalar arthrodesis for symptomatic subtalar OA is 3.3% in patients who had operative treatment of the fracture and about 16.9% in patient who were treated nonoperatively.

The outcome of treatment of calcaneal fractures has not been good but most of recent studies show that open reduction and internal fixation has better outcome in selected patients.

References

1. Daftary A, Haims AH,Baumgaertner MR. Fractures of the Calcaneus: A Review with Emphasis on CT.
2. Carr JB, Hamilton JJ, Bear LS. Experimental intra-articular calcaneal fractures: anatomic basis for a new classification. Foot Ankle 1989; 10:81–87.
3. Eastwood DM, Phipp L. Intra-articular fractures of the calcaneus: why such controversy? Injury 1997;28:247–259.
4. Essex-Lopresti P. The mechanism, reduction technique, and results in fractures of the os calcis. Br J Surg 1952;39:395–419.
5. Sanders R, Fortin P, DiPasquale T, Walling A. Operative treatment in 120 displaced intraarticular calcaneal fractures: results using a prognostic computed tomography scan classification. Clin Orthop Relat Res 1993;290:87–95.
6. Sanders R, Gregory P. Operative treatment of intra-articular fractures of the calcaneus. Orthop Clin North Am 1995;26:203–214.
7. Sanders R. Intra-articular fractures of the calcaneus: present state of the art. J Orthop Trauma 1992;6:252–265.
8. Furey A, Stone C, Squire D, Harnett J. Os calcis fractures: analysis of interobserver variability in using Sanders classification. J Foot Ankle Surg 2003;42:21–23.
9. Vasukutty N, Kumar V, Diab M2, Moussa W1. Operative treatment of calcaneal fractures: improved outcomes and low complications rates with a strict management protocol. Ann R Coll Surg Engl. 2017 Apr;99(4):275-279.
10. Fitzgibbons T, McMullen ST, Mormino MA. Fractures and dislocations of the calcaneus. In: Bucholz RW, Heckman JD, eds. Rockwood and Green’s fractures in adults. Philadelphia, Pa: Lippincott Williams & Wilkins, 2001; 2133–2179.
11. Loucks C and Buckley R. Bohler's angle: correlation with outcome in displaced intra-articular calcaneal fractures. J Orthop Trauma. 1999 Nov;13(8):554-8.
12. Buckley R, Tough S, McCormack R. Operative compared with nonoperative treatment of displaced intra-articular fractures: a prospective, randomized, controlled multicenter trial. J Bone Joint Surg Am 2002;84:1733-44.
13. Park YH, Lee JW,. Hong JY, Choi GW, Kim HJ. Predictors of compartment syndrome of the foot after fracture of the calcaneus. Bone Joint J 2018;100-B:303–8.
14. Bezes H, Massart P, Delvaux D, Fourquet J P, Tazi F. The operative treatment of intraarticular calcaneal fractures. Indications, technique, and results in 257 cases. Clin Orthop 1993; (290): 55-9.
15. Zwipp H, Tscherne H, Thermann H, Weber T. Osteosynthesis of displaced intra articular fractures of the calcaneus. Results in 123 cases. Clin Orthop 1993; (290): 76-86.
16. Parmar H V, Triffitt P D, Gregg P J. Intra articular fractures of the calcaneum treated operatively or conservatively. A prospective study. J Bone Joint Surg (Br) 1993; 75 (6): 932-7.
17. Thordarson D B, Krieger L E. Operative vs. nonoperative treatment of intra articular fractures of the calcaneus: a prospective randomized trial. Foot Ankle Int 1996; 17 (1): 2-9.
18. Randle J A, Kreder H J, Stephen D, Williams J, Jaglal S, Hu R. Should calcaneal fractures be treated surgically? A meta-analysis. Clin Orthop 2000; (377): 217-27.
19. Westphal T, Piatek S, Halm JP, Schubert S and Winckler S (2004) Outcome of surgically treated intraarticular calcaneus fractures—SF-36 compared with AOFAS and MFS, Acta Orthopaedica Scandinavica. 2004; 75:6 : 750-755.
20. Veltman ES, Doornberg JN, Stufkens SA, Luitse JS, van den Bekerom MP.  Long-term outcomes of 1,730 calcaneal fractures: systematic review of the literature. J Foot Ankle Surg. 2013 Jul-Aug;52(4):486-90.