Minimally invasive osteosynthesis and general management of calcaneal fractures

The majority of calcaneal fractures are intraarticular (93%); most of them are displaced and require surgery. Classical surgical techniques all have significant drawbacks

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  Studies of open reduction and internal fixation (ORIF) of calcaneal fractures in large patient cohorts show rates of wound edge necrosis between 2–11%, and soft-tissue infection rates between 1.3–7% [ 2, 4– 9].

  
  
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  Closed reduction and internal fixation (CRIF) of severely displaced intraarticular fractures carries the considerable risk of residual joint incongruity with a poor final outcome [ 10– 14].

  
  
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  Superficial pin-track or K-wire infection may develop into deep infection in up to 3.5% of cases [ 15– 17]. Some loss of reduction is reported after percutaneous K-wire fixation in 4–67% of cases [17– 19].

In an effort to reduce these problems, minimally invasive osteosynthesis (MIO) of intraarticular calcaneal fractures (Sanders types IIA and IIB) AO-ICI-Classification 8.82.B1.1 to B1.2 respectively, aims to achieve percutaneous screw fixation thus eliminating the risk of pin-track infection. The technique also involves exact intraoperative control of the anatomical joint reduction—which is essential for functional outcome—either using three-dimensional (3-D) image intensification or subtalar arthroscopy.

Indications for operative treatment

The advent of CT scans of calcaneal fractures in the 1980s gave surgeons a much clearer understanding of the fracture pathology and led to a new era of open operative treatment. Existing percutaneous K-wire fixation or primary nonoperative treatment had led to unsatisfactory results. Experimental studies have shown that even a minor step-off of 1–2 mm within the posterior facet of the calcaneus alters the weight distribution significantly, a factor that may contribute to arthritis later on [ 20, 21]. Clinical evaluation of ORIF has shown that a residual step-off within the posterior facet of more than 1 mm results in less favorable clinical outcomes [ 6, 9, 22– 25].

Operative treatment of displaced intraarticular calcaneal fractures is indicated in healthy and active patients without any contraindications to surgery. Contraindications include poor soft-tissue status, blowout fractures that are not amenable to reconstruction, substance abuse, noncompliance, poorly controlled diabetes mellitus (especially with neuropathy), symptomatic peripheral vascular disease, and significant depression of the immune system.

Conventional treatment methods: conservative versus surgical

One prospective randomized study compared nonoperative treatment with ORIF in displaced, intraarticular calcaneal fractures in 34 patients. This study showed significantly better results when ORIF was compared to nonoperative treatment. All operations were carried out by a single surgeon [ 26].

A prospective randomized multicenter trial with 424 enrolled patients indicated certain patient subgroups that benefited from operative treatment [ 24]. While the overall outcome of the whole group as measured by the SF-36 and visual analog scoring was not significantly better, fewer subtalar fusions were necessary after operative treatment and this finding was statistically significant. Furthermore, women and patients who did not receive worker‘s compensation who were treated by surgery did significantly better as measured by functional scoring compared with those treated by nonoperative management. Among those who did not receive worker‘s compensation, younger patients (less than 29 years old), patients with a moderately lower Böhler‘s angle, a comminuted fracture, an anatomical reduction, or step-off less than 2 mm scored significantly higher when treated surgically [24].

Several retrospective clinical studies have shown significantly better functional results after ORIF compared to non-operative treatment [ 27– 29]. Others did not find significant differences between ORIF and nonoperative treatment when the patient groups were studied as a whole but improved outcome for those patients treated by ORIF in those subsets of patients in whom anatomical reduction could be achieved by operative treatment [ 30]. The worst results are to be expected when operative treatment with extensile approaches does not result in anatomical reconstruction of the calcaneus [ 31].

The authors of larger series have highlighted a considerable learning curve [2, 4, 5, 32]. On the other hand, conservative treatment of displaced calcaneal fractures frequently leads to severe functional impairment with considerable disability and the need for subsequent corrective surgery [4, 33– 36].

Different methods of fixation

There are several implants available for fixation of displaced calcaneal fractures which include:

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   Anatomically shaped nonlocking plate

   
   
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   Anatomically shaped locking plate

   
   
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   Reconstruction plate 3.5

   
   
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   3.5, 4.0, 4.5, and 6.5 mm diameter screws

   
   
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   External fixation device

   
   
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   K-wire or Steinmann pin

The type of implant, surgical approach, technical reduction maneuver, and timing for surgery are related to the fracture type, soft-tissue damage, bone quality, and the personal experience of the treating surgeon. In cases of comminuted fractures, osteopenic or osteoporotic bone, for example, the use of an interlocking plate is preferable. With severe soft-tissue damage, external fixation devices or percutaneous pinning is beneficial either as a temporary or permanent measure.

Is there a place for MIO in fixation of calcaneal fractures? If so, what are the advantages and disadvantages?

The main advantage of MIO in the treatment of calcaneal fractures is the minimal additional soft-tissue trauma that results from surgery when compared to extensile approaches that will invariably lead to significant scarring and a higher risk of postoperative wound healing problems. This leads to a shorter duration of surgery, hospital stay, rehabilitation period, and a better hindfoot range of motion when MIO is compared to ORIF [ 37].

The main disadvantage of MIO is the difficulty of obtaining anatomical reduction of both the outer shape of the calcaneus and the joint surfaces by purely percutaneous techniques, especially in cases of multiple fragmentation and delayed referral of the patient. Minimally invasive osteosynthesis is best performed within the first 3 days after the injury and difficult to perform after more than 10 days because fibrous union of the fragments is beginning. Joint reduction is essential and cannot be controlled by direct visualization. Either 3-D image intensification or arthroscopic control has to be used [ 38, 39]. If anatomical reduction cannot be achieved due to deep impaction of the joint-bearing fragments, further fragmentation during percutaneous manipulation, fibrous union, or bone and soft-tissue interposition, the surgeon must switch to open reduction which at that stage may put further strain on the soft tissues. Minimally invasive osteosynthesis is therefore a demanding procedure because it requires a surgeon who is also skilled in both open calcaneal reconstruction and subtalar arthroscopy.

Indications and contraindications for MIO

A balanced approach is beneficial for the treatment of calcaneal fractures. Minimally invasive osteosynthesis with image intensifier control is indicated for all extraarticular fractures (AO-ICI type A) with relevant displacement (varus > 5°, valgus > 10°, more than 20% of widening or loss of height) and for intraarticular calcaneal tongue type fractures (AO-ICI type B1) in which the posterior facet is displaced as a whole (Sanders type IIC) [ 40, 41]. It can also be advised in moderately displaced intraarticular fractures with one fracture line crossing the posterior facet of the subtalar joint (Sanders types IIA and IIB). Such cases require the use of percutaneous screw fixation under image intensifier or arthroscopic control [ 11, 38]. Note that achieving anatomical reduction with percutaneous methods is—if done correctly—a demanding procedure. It is best performed within the first 7 days after injury and gets increasingly difficult if surgery is delayed for more than 10 days [37, 41].

Special aspects for calcaneus

The calcaneus has four articular facets of which the posterior facet and the middle facet seem to be the most important ones related to weight-bearing stress and the necessity to achieve absolute anatomical reconstruction ( Fig 22.1-1 ). Due to the anatomy of the fracture, tongue type fractures are best reduced with the Westhues maneuver [ 42]. This maneuver was described as early as 1934 by the German surgeon Westhues and is therefore referred to as the “Westhues maneuver” [ 43]. It was later popularized in the English-speaking literature by Gissane from England and Essex-Lopresti from Australia. A Schanz screw with handle is inserted into the tuberosity fragment and the maneuver can be accurately controlled by image intensification only. In contrast, joint-depression type fractures may need additional percutaneous manipulation and mandatory arthroscopic control of joint reduction is required. The sustentaculum tali has the strongest cortex and should be aimed for in cases of screw fixation. Placing the patient in the lateral decubitus position allows the best lateral view to be obtained by the image intensifier as well as Brodén‘s views of the calcaneus and 3-D scanning. Additional arthroscopy of the subtalar joint also requires a lateral decubitus position for controlling the percutaneously performed disimpaction of the displaced posterior facet.

When placing the standard arthroscopic portals and the stab incisions for K-wires and screws, the course of the sural nerve, the lateral branches of the superficial peroneal nerve, and the peroneal tendons have to be respected ( Fig 22.1-2 ). When drilling K-wires and screws on the medial side, the course of the medial neurovascular bundle should be borne in mind.

Fracture and soft-tissue assessment

Preoperatively the general condition of the patient should be assessed. The condition of the skin and underlying soft tissues as well as the neurovascular status of the lower limb must be evaluated. The examining surgeon should also focus on diagnosing associated foot fractures and excluding a compartment syndrome of the foot.

Type of x-rays and CT scans

Radiological assessment includes plain lateral and dorsoplantar x-rays of the foot plus an axial view of the calcaneus. Special projections like a Brodén view with 20° of tilting are particularly useful for intraoperative imaging and control of reduction. A CT scan is mandatory in every case of a suspected calcaneal fracture to make the diagnosis and in every case of proven fracture to decide the indication for surgery. CT scans are essential for preoperative planning. A 3-D CT reconstruction is optional and helpful in cases of complex and rare fracture patterns.

Choice of implants

Depending on foot size and quality of bone stock 6.5, 4.5, 4.0, or 3.5 mm screws of different length with a maximum up to 75 mm are needed. If percutaneous fixation is performed as a temporary measure, K-wires (1.8 to 2.5 mm) and/or an external fixator are used.

Timing of surgery

Use of an arteriovenous foot pump, ice cooling, lymph drainages, and elevation should minimize swelling and accelerate time to surgery. Surgery should be possible within the first week, preferably within 3–5 days. A reliable clinical sign of recovered soft tissues is the wrinkling of the skin over the lateral calcaneal wall.

In polytraumatized patients with significantly displaced fractures and cases of fractures and fracture dislocations with impeding soft-tissue breakdown, an approximate closed reduction should be performed as an emergency procedure to minimize strain on the soft tissues. Definitive fixation, mostly ORIF, is performed after improvement of the soft tissues and the patient‘s overall condition [ 34].

Preoperative planning

The preoperative CT scan has to be evaluated thoroughly in the axial, coronal, and sagittal reconstructions to decide if the fracture is amenable to percutaneous reduction and how the reduction maneuver should be performed. It is important to distinguish between tongue type and joint-depression type fractures, the amount of joint involvement, impaction, and the presence and amount of tilting of the medial part of the posterior facet. The reduction maneuver, setup for image intensifier and arthroscopic control, and type of screw fixation should be planned accordingly.

Anesthesia

Generally, spinal or epidural anesthesia is recommended. For optimal postoperative pain control a distal ischiadic nerve catheter can be preoperatively inserted under sonographic control to alleviate pain during early mobilization of the patient.

Patient and of image intensifier positioning

The patient is placed in lateral decubitus position on the uninjured side. The foot and lower leg are disinfected up to the proximal third of the lower leg. The whole leg should be draped so that the limb is freely mobile to allow the axial, dorsoplantar, and Brodén image intensifier projections used to control reduction to be obtained. For 3-D image intensification a radiolucent carbon table is needed. Ensure that the image intensifier can rotate freely and completely before starting the operation. In case of an isolated sustentacular fracture the patient is positioned supine to allow the screw to be inserted from the medial side.