Complications and early results after operative fixation of 68 pilon fractures of the distal tibia

Abstract

Background and aims

In this cohort study, we present comprehensive injury specific and surgical outcome data from one of the largest reported series of pilon fractures of the distal tibia treated in a UK tertiary referral centre.

Methods and results

A series of 68 closed pilon fractures were retrospectively reviewed from case notes, plain radiographs and computed tomography imaging. Patient demographics, injury and fracture patterns, methods and timing of fixation and clinical and radiological outcomes were assessed over a mean follow-up period of 7.7 months (1.5–30). Overall, deep infection occurred in 1.6% with superficial infection and wound breakdown occurring in 6.3% of cases. Rates of nonunion and malunion were 7.8%. Radiological posttraumatic arthritis was present in 26.6%, which was symptomatic and requiring orthopaedic management in 9.4%. Further surgery for all causes occurred in 26.6% of cases.

Conclusion

Fixation of these complex fractures in subspecialist units can achieve overall low rates of wound complications, with definitive fixation of selected fractures within 48 h of initial presentation achieving comparable results to those fixed in a delayed fashion. However, this injury continues to have a significant overall complication rate with a high chance of developing early posttraumatic arthritis and of requiring further surgery.

Keywords

Pilon distal tibia fracture outcomes

Introduction

Fractures of the distal articular surface of the tibia are commonly referred to as pilon fractures. These are complex intra-articular injuries sustained from an axial load to the tibia and frequently one of high energy. Reconstruction of these fractures poses significant challenges, not only in restoring the complex bony architecture of the fracture but also in the management of the surrounding soft tissues. The aim of surgical management is to anatomically reduce and fix the intra-articular fragments and restore the length, alignment and rotation of the distal tibia. This must all be done with minimal surgical soft tissue trauma and maintaining a sufficient soft tissue envelope around the fracture to promote wound healing and fracture union.

Since the first reported results of the fixation of these fractures by Reudi and Allgower in 1969,¹ advances in preoperative imaging, an increased appreciation of the importance of the soft tissues and developments in implant design has improved our capability to successfully manage these fractures. This cohort study reports complications and early results from operative fixation of 68 pilon fractures performed in a UK tertiary referral centre.

Patients and methods

All patients undergoing surgery for intra-articular fractures of the distal tibia from May 2010 until August 2012 were identified from our departmental database. Of these fractures (110), 77 true pilon fractures were identified. There were 71 patients with unilateral fractures and 3 patients with bilateral fractures. We excluded open fractures (6), fractures treated with only percutaneous fixation (2), and fractures managed conservatively (1).

In all, 68 closed tibial pilon fractures (65 patients) treated with open reduction and internal fixation (ORIF) remained for inclusion in this study. Patients underwent definitive surgery across two separate hospital sites under the care of eight subspecialist foot and ankle or trauma/lower limb orthopaedic surgeons. Patients had their surgery performed by the consultant or by an orthopaedic registrar, under direct supervision by the consultant in charge. All patients had their case notes and imaging reviewed by the lead author.

Results

Demographics

There were 46 male (3 with bilateral fractures) and 19 female patients. The mean age was 39.9 years (range 15–69). There were 39 high-energy and 29 low-energy fractures.

Fracture patterns

Fractures were classified by their appearance on X-ray using the Arbeitsgemeinschaft fur Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) system, and computed tomography (CT) using the classification described by Topliss et al.² The majority of fractures (42/68) were classified as AO/OTA C-type fractures (complete articular) and of those most (27/42) were of the subtype C3 (articular multi-fragmentary) indicating the most severe form of intra-articular injury. CT scans revealed a broad and diverse group of fracture patterns fitting into each of the 10 subsets described by Topliss et al.

The fibula was fractured in 45 cases. The fracture level was classified as Weber B in 20 and Weber C in 25. There were additional foot and ankle injuries in 7 patients and other associated injuries in 12 patients.

Treatment

Bridging external fixators were applied acutely as a temporary means of achieving fracture stability in 19 cases at the discretion of the receiving surgeon at the time of presentation. One patient from this group also had definitive internal fixation performed at the same time, with the external fixator used to augment the fracture stability. Definitive treatment methods are summarised in Table 1. Decisions regarding fixation technique were surgeon dependent and were made after review of the patient and their preoperative imaging and also of the intraoperative findings during surgery. Figure 1 shows an example case.

Table 1.

Definitive fixation method used for the tibia.

Treatment method	Number
Locking plate + additional screws	42
Locking plate only	11
Screws only	7
Plate + bridging external fixator	3
Non locked plate + additional screws	3
Non locked plate only	2

Figure 1.

Plain radiographs of a pilon fracture of the distal tibia with associated fracture of the fibula. The initial radiographs on presentation to the Emergency Department are shown (left and centre left), along with the same fracture after open internal fixation (centre right and right).

The number of separate incisions used for overall fracture fixation was 1 (35), 2 (22) or 3 (11). Three incisions were used when fixation of the tibia required double plating and in addition there was fixation of the associated fibula fracture through a third lateral incision. The approaches used for fixation of the tibia are shown in Table 2. Application of a second plate to the tibia was decided at the discretion of the operating surgeon, after assessing the fracture pattern and also the intraoperative stability of the construct as surgery progressed. This necessity for additional stability from a second plate applied to the tibia most likely reflects the higher complexity of the fracture patterns in this group. The proportion of the more severe AO/OTA C-type fractures in the double plating group was higher (85%) than in the single plating group (57%).

Table 2.

Surgical approach used for fixation of the tibia.

Primary approach to the tibia	Secondary approach to the tibia if used	Number	Total
Anterior		20	24
Anterior	Medial	4	24
Anterolateral		13	22
Anterolateral	Medial	9	22
Medial		15	15
Anteromedial		5	5
Posterior		1	1
Posterolateral		1	1

The mean time from presentation at the Emergency Department to definitive fixation was 5.6 days (range 1–22 days). The decision of timing for the definitive surgery was made by the consultant in charge of that patient. This depended on the timing of transfer from peripheral hospitals, the condition of the soft tissues on preoperative review, the accessibility of early CT imaging and also on the availability of that subspecialist surgeon to perform the definitive fixation.

Follow-up

There were 57 fractures that were either discharged (n = 48; mean follow-up 6.8 months; range 2–23) or remained under follow-up (n = 9; mean follow-up 15.9 months; range 9–30) for which a complete set of follow-up data was available. Partial follow-up data was available for seven more fractures. These patients failed to attend some of their scheduled appointments, but they all attended in the early postoperative period and were lost to follow-up at a mean of 2.8 months post surgery (range 1.5–5 months). They all had X-rays and clinical notes available for review. None of these patients were re-referred and all were progressing well at their last clinic visit. Outcome data is included for these patients and they are considered to have no further complications within the time frame of this review.

Of the remaining four patients with no follow-up data, there were two who failed to attend sufficiently for inclusion in this study. One attended on a single occasion at two weeks postoperatively and the second patient never attended our institution again after discharge. These patients are considered lost to follow-up and are excluded from further data analysis. Neither has been referred back to our unit. The final two patients who were not followed up were holidaying in our region and subsequently returned to their country of origin after discharge. We have no access to their hospital records and they are therefore excluded.

Included in the final outcome data therefore are a total of 64 out of 68 fractures with mean overall follow-up of 7.7 months (1.5–30). Our loss to follow-up rate is 5.9% (4/68).

Complication summary

All complications are summarised in Table 3.

Table 3.

Complication summary.

Complication	Total	%
Superficial infection	4/64	6.3
Aseptic wound breakdown	4/64	6.3
Deep infection	1/64	1.6
Pin site infection (external fixator)	1/3	33.3
Malunion	5/64	7.8
Nonunion	5/64	7.8
Radiological posttraumatic arthritis	17/64	26.6
Posttraumatic arthritis requiring orthopaedic treatment	6/64	9.4
Further surgery	17/64	26.6

Infection and wound complication

For the purpose of this study, a diagnosis of superficial infection is defined as an infection involving superficial tissues only and not extending down to bone, implanted metalwork of the deep tissues surrounding it. These were diagnosed and treated on clinical and/or microbiological evidence and responded to a course of antibiotics without the need for surgical intervention. Deep infection is defined as an infection involving the tissues and/or bone surrounding the implanted metalwork. These infections were managed with a combination of surgical and medical intervention. Details of infected cases are shown in Table 4.

Table 4.

Details of all infected cases.

Type	Bacteriology	Definitive fixation method	Incisions made	Time to definitive fixation	Treatment
Deep	1. Staphylococcus aureus 2. Enterococcus 3. Mixed anaerobes	ORIF + Ex fix	1. Anterior 2. Lateral	9 days	1. Distal tibia resection for osteomyelitis 2. Tibiotalar fusion with circular frame and concurrent limb lengthening from proximal tibia
Sup.	Staphylococcus aureus	ORIF	1. Anterior 2. Lateral	4 days	One week of oral antibiotics
Sup.	No growth – clinical diagnosis	ORIF	1. Medial	1 day	Oral antibiotics (duration unclear)
Sup.	Nil sent – clinical diagnosis	ORIF	1. Medial	4 days	One week of oral antibiotics
Sup.	No growth– clinical diagnosis	ORIF	1. Medial 2. Lateral	5 days	Required intravenous then oral antibiotics (duration unclear)

Definitive fixation was performed at a variety of time intervals as discussed in a previous section. Early definitive fixation (definitive surgery performed up to 48 h after presentation to the Emergency Department) did not appear to be related to an increased risk of wound complications, with a rate of infection in these cases of 4.5% (1/22) and aseptic wound breakdown of 4.5% (1/22). In this subgroup, the fracture classification was AO/OTA B type in 11 cases and C type in 11 cases. In those patients in whom definitive fixation was delayed until seven days or more, the rate of infection was 4.8% (1/21) and aseptic wound breakdown was also 4.8% (1/21). In this subgroup, the fracture classification was AO/OTA B type in 6 cases and C type in 15 cases.

In fractures where the tibia was fixed with a two-incision technique and double plating, the combined rate of infection or wound complication was 23.1% (3/13). This compares with 11.7% (6/51) after single incision approach with single plating of the tibia.

Other early complications

Other early complications were of iatrogenic nerve injury in a single case. This patient complained postoperatively of altered sensation and paraesthesia in the distribution of the saphenous nerve, which did not resolve.

Nonunion

Nonunion occurred in five patients, all of whom underwent revision surgery. Fracture classification was AO/OTA B type in one case and C type in four cases. Definitive initial fixation was with single tibial plating in four cases and double tibial plating in one case. The fibula was not plated in any of these fractures. Two of these patients were treated for superficial wound infection after the initial surgery although neither had positive samples from wound swabs taken at the time. In addition, multiple deep tissue samples taken at the time of nonunion surgery did not provide any positive bacterial growth and so infected nonunion was felt unlikely. Three of these patients remain under follow-up in our limb reconstruction unit.

Early posttraumatic arthritis

Review of the most recent radiographs revealed that 17 patients (26.6%) had some evidence of posttraumatic arthritis. Six of these patients were undergoing treatment of this by an orthopaedic foot and ankle surgeon in our unit. Two patients had undergone open ankle fusion within one year post injury. Two patients had undergone arthroscopic debridement of anterior osteophytes and a further two patients were being managed conservatively and remained under follow-up, with a possibility of requiring surgical intervention in the near future.

Further surgery

Of the patients requiring further surgery (17), the reasons were for removal of painful/prominent metalwork (8), treatment of nonunion (5), ankle fusion for posttraumatic arthritis (2), surgery for deep infection (1), and osteotomy for correction of malunion (1).

Discussion

The term pilon, meaning pestle, was first introduced as the descriptive term for this injury by the French radiologist Destot, in 1911.³ It describes the impact of the talus against the distal tibial articular surface, conveying the mechanism of injury for this fracture as a high-energy axial load. It was Reudi and Allgower working in the AO group in 1969 who first described and popularised an operative approach to the treatment of pilon fractures.¹ In their description of the optimum surgical treatment, they advocated fixation of these fractures with meticulous effort made to anatomically restore the articular surface, using extensive soft tissue dissection to gain access to the tibial fracture components. For adequate fixation of these injuries, they described four key principles: (1) restoration of the anatomical length of the fibula, (2) anatomical reconstruction of the tibial articular surface, (3) bone grafting of the metaphyseal defect, (4) medial buttress plate fixation. Using these principles, they reported a series of 84 patients at mean follow-up of 50.3 months showing good functional results in 73.7%. Deep infection was present in 5% with overall soft tissue complications of 12%.¹ Good long-term results were again presented in a further paper 10 years later.⁴

This approach grew in its popularity, but the initial enthusiasm was followed by numerous disappointing reports of high rates of wound dehiscence, infection and osteomyelitis.^5–11 The importance of respecting the soft tissues in order to minimise wound complications was beginning to emerge. This brought about the development of a two-stage technique for management, which was advocated as a safe method to protect the soft tissue envelope. The first stage involved the application of an external fixator to stabilise the fracture and preserve and rest the surrounding soft tissues. A second stage then focussed on delayed definitive reduction and stabilisation of the articular fragments and anatomical restoration of length and alignment.^12,13 Good results were reported using this technique,^12–14 but others failed to replicate this. In a trial of two methods of treatment, Blauth et al. demonstrated comparatively poor results across groups treated with immediate fixation and those treated with a two-staged approach.¹⁵

More recent literature has once again moved towards an approach of early definitive fixation with good results after early surgery before the onset of significant soft tissue swelling. White et al. showed that in AO/OTA C-type fractures, direct open reduction within 36 h of injury by trauma surgeons in a level-1 trauma centre is associated with a wound complication rate requiring further surgery of 2.7% after closed fracture.¹⁶ They accept that their results go against previously published unfavourable data on early fixation. It was felt by the authors that this was as a result of advances in fixation technology producing better construct rigidity and also the window of opportunity for safe early surgery falling within 36 h.

An appreciation of the anatomy of the fracture using CT imaging is of paramount importance and preoperative CT scanning has been shown to enhance the understanding of fracture anatomy compared to that seen on plain radiographs.¹⁷ McCann et al. have shown that good early results with low rates of deep infection could be achieved by using the CT scan to guide a ‘direct approach’ to the primary fracture line, with the incision made exactly over the main fracture line to allow anatomical reduction with minimal associated soft tissue stripping.¹⁸

Using preoperative CT scanning in our series, the surgical approach was tailored to the fracture configuration using this ‘direct approach’ technique, providing excellent visualisation of the main fracture fragments. Anatomical reduction of the key components of the articular surface of the distal tibia can then be achieved, whilst maintaining the soft tissue envelope around the fracture with as minimal soft tissue trauma as possible. What results in our series are the utilisation of a variety of surgical approaches, each tailored specifically to the fracture pattern and taking into account the visual condition of the soft tissues on preoperative assessment. Using this strategy for both delayed and early definitive fixation has resulted in low rates of wound complication and infection, which compare well to those reported recently using similar techniques.^16,18

Conclusion

This study reports early outcomes and complications from one of the largest series of closed pilon fractures of the distal tibia treated in a UK tertiary referral centre. Using modern techniques of preoperative planning and surgical implant fixation, complications can be minimised and good early results can be achieved. In a specifically selected subgroup of patients, definitive fixation performed up to 48 h after initial presentation can produce comparable early wound complication rates to those managed in a delayed fashion. However, significant complications from this injury do remain. There is a high likelihood of further surgery and the risk of developing posttraumatic arthritis is high, even in the short-term follow-up of this study.

Footnotes

Declaration of conflicting interests

None declared.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

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