Minimally Invasive Plate Osteosynthesis for Tibial Pilon Fractures (Case Series)

 Abstract

Background Fractures of the tibial plafond are rare injuries that present a challenge as to their best method of management. The involvement of the ankle joint and the vulnerability of the surrounding soft tissues further complicate these already complex injuries. Minimally invasive plate osteosynthesis (MIPO) is becoming a popular method of treating these injuries when there is no articular comminution and the soft tissue envelope is minimally disturbed.Patients and methods Seventeen patients with tibial pilon fractures were treated by MIPO using an anatomical distal tibial plate. Seven patients had associated skeletal injuries. Two patients had a grade I open fracture. Results All fractures united at an average of 13 weeks. Seven patients (40%) were pain-free, 5 patients (30%) had pain after stressful activities, 3 patients (18%) had mild to moderate pain requiring analgesics, one patient (6%) had moderate pain causing restriction of activities, and one patient (6%) had continuous pain. Twelve patients (71%) had excellent or good results. Two patients had a superficial wound infection, 2 patients complained of prominence of the plate, and two patients had radiological evidence of degenerative changes in the ankle. Conclusion Minimally invasive plate osteosynthesis is a good and safe technique for treatment of distal tibial fractures without intra-articular comminution providing fracture healing, rapid functional recovery, and avoidance of major complications.

Introduction

Fractures of the tibial plafond are rare injuries that present a challenge as to their best method of management. The involvement of the ankle joint and the vulnerability of the surrounding soft tissues further complicate these already complex injuries. Numerous classifications have been proposed for these fractures, however, the AO-OTA alphanumeric classification^1,2is the most comprehensive as well as the most commonly quoted classification.  Ruedi and Allgower³ popularized open reduction and internal fixation (ORIF) for these fractures and established treatment guidelines. However, their impressive results were not paralleled by other authors and subsequent reports showed a significant number of major complications.^4,5 This was mainly attributed to lack of appreciation of the damage to the soft tissues, and on the other hand attempting to apply the principles of ORIF to all types of pilon fractures without discrimination.⁶ This led to a change of the philosophy of treating such injuries with more respect to the soft tissues and a tailored management of different fracture types. The classic ORIF with buttress plating became more and more replaced with other methods of fixation. Currently two methods are gaining popularity. One method is wire fixators, which is useful in highly comminuted fractures with significant soft tissue damage. The other method is minimally invasive plate osteosynthesis (MIPO), when there is no articular comminution and the soft tissue envelope is minimally disturbed.^6,7

Patients and methods

This prospective study involves 17 patients with tibial pilon fractures who were operated on in the casualty unit of the Orthopaedic department, Zagazig University Hospitals between January 2005 and August 2006. There were 11 males and 6 females. The age ranged from 21 to 55 (mean 34 years). The right side was involved in 9 patients and the left side was involved in 8 patients. Ten patients were involved in a motor vehicle accident, 6 fell from a height, and one was injured in a sporting accident. Ten patients had no associated injuries, while the remaining 7 patients had various associated skeletal injuries including 1 ipsilateral femoral shaft fracture, 2 contralateral femoral shaft fractures, 2 contralateral supracondylar femoral fractures, 1 contralateral bimalleolar fracture, 1 contralateral tibial shaft fracture, and 2 vertebral fractures. These associated injuries were all given the appropriate management.

Two patients had a grade I open fracture according to the Gustilo and Anderson classification.⁸ Two of the remaining 15 patients with closed injuries had grade I soft tissue damage according to the Tscherne and Gotzen classification of closed injuries.⁹ According to the AO-OTA classification, 10 fractures were type C 1, and 7 fractures were type C 2. All patients had an associated fibular fracture.

The patients were examined clinically to evaluate the soft tissue condition, and X rays were obtained in the anteroposterior, lateral, and mortise views. In all patients CT scans were performed to evaluate the intra-articular injury. Ten patients were operated on within 24 hours, while 7 patients were postponed to allow their general condition to stabilize. Three were operated on the next day and 4 were operated on the third day of the injury.

Surgical technique

Patients were operated on under general or regional anaesthesia, on a standard radiolucent orthopaedic table, under image intensifier guidance. One gram of 3^rd generation cephalosporin was given with induction of anaesthesia and the antibiotic was continued for 3 days postoperatively. A pneumatic tourniquet was inflated on the thigh except in the case with ipsilateral femoral fracture. In the 2 open fractures; the first step was wound lavage and debridement. Next, the fracture was reduced by manual traction and the reduction checked by the image intensifier. Then the fibula was fixed through a posterolateral approach by a one-third tubular plate and screws. In 3 cases the fibular fracture was not fixed as it was high and was judged to have little effect on the stability of the ankle joint. Provisional fixation of the articular fragments was done percutaneously with pointed reduction clamp and K wires which were removed later. In 15 cases, fixation of the articular fragments by lag screws outside the plate was performed percutaneously through stab incisions. Next, a 3 cm incision was made over the medial malleolus. In one of the 2 open fractures, this incision incorporated the open debrided wound. From this incision, a subcutaneous extraperiosteal tunnel was created for the introduction of the plate, using a long blunt instrument. The plate used in all cases was the Anatomical Distal Tibial Plate, which is a prebent plate that matched the anatomy of the distal tibia . Then the plate was passed in this tunnel. Another 3-4 cm incision was made over the proximal end of the plate. The proximal incision was used for insertion of 3 cortical screws 4.5 mm into the proximal 3 holes fixing the plate to the intact tibial diaphysis proximal to the most proximal end of the fracture. The final step was insertion of 2 (10 cases) or 3 (7 cases) fully threaded cancellous screws 6.5 mm through the distal end of the plate to fix the articular fragments. The wound was closed, and a posterior slab was applied.Post-operatively, AP and lateral radiographs were used to check the fracture reduction and the congruency of articular surface of the ankle.

Postoperatively, the leg was elevated and anti-oedema drugs were given to guard against postoperative oedema. The slab and the stitches were removed 2 weeks postoperatively, and gentle active mobilization was started.

Follow up

The patients were reviewed at 2 weeks, 1 month, 2 months, 3 months, then every 3 months during the first year and yearly thereafter. The average follow up was 25 months (range: 18 to 38 months). During follow up visits, the patient was examined clinically and X rays anteroposterior and lateral views of the leg and ankle were obtained. Partial weight bearing was allowed when radiological union was evident on X rays, progressing to full weight bearing over one month.

Results

All fractures united at an average of 13 weeks (range 9 to 17 weeks). As regards pain, 7 patients (40%) were pain-free, 5 patients (30%) had only occasional pain after stressful activities and not requiring medication, 3 patients (18%) had mild to moderate pain requiring analgesics, one patient (6%) had moderate pain causing restriction of activities, and one patient (6%) had continuous pain regardless of activity. Ten patients (59%) could walk for an unlimited distance, 4 patients (24%) could walk more than 1 Km, 2 (11%) could walk approximately 0.5 Km, and one patient (6%) could only walk indoors. The average dorsiflexion was 12º (range: 0 – 15º), and the average plantarflexion was 25º (range: 10 – 30º). According to the clinical rating system by Teeny and Wiss¹⁰, 12 patients (71%) had Excellent or Good results, 3 patients (18%) had Fair results, and 2 patients (11%) had poor results. Radiologically, one fracture united with 5º varus angulation, and 2 fractures united with 5º recurvatum.

Figure 1a.	Figure 1b.
Figure 1c.	Figure 1d.
Figure 1e.	Figure 2b.

Complications

Major complications were those that required unforeseen operative intervention as a direct result of morbidity from the fracture or the treatment method such as osteotomies for malunions or nonunions, deep infections, wound breakdown requiring soft tissue coverage, and failures of fixation. All other events that did not require formal operative intervention such as superficial wound infections, and delayed unions were therefore considered minor local complications.^5,11 According to these criteria, no major complications were encountered in this series, while 2 patients had a superficial wound infection that responded to medical treatment and dressing, 2 patients complained of prominence of the plate. Two patients had radiological evidence of degenerative changes in the ankle joint by the final follow up. One of them was managed medically by non-steroidal anti-inflammatory drugs, while the other was scheduled for an ankle arthrodesis.

Discussion

The landmark paper by Ruedi and Allgower³ with 74% of their patients free from pain and with good functional results at four years follow-up revolutionized the management of pilon fractures which were treated predominantly conservatively before that. Thereafter, the 1970's and 1980's witnessed widespread application of the principles of ORIF in the management of pilon fractures. However, this was accompanied by a shockingly high rate of major complications including nonunion up to 18%, superficial infections up to 20%, osteomyelitis up to 17%, arthrodesis rates of 27%, below knee amputation rates of 6%, post-traumatic osteoarthrosis rates of 54% and mal-unions in 42% of patients.⁴ These high rates of complications led surgeons to the conclusion that in the management of Pilon fractures, soft-tissue management is as important as the bony reconstruction.⁵ On the other hand, analysis of Ruedi and Allgower's series which still had good results at 9 years follow up¹² showed that the type of trauma was primarily low-energy injuries. They presented another series¹³ in 1979 which consisted of high-energy injuries and found that the overall results were not as good as those in patients with lower-energy injuries. This has led many authors to conclude that the avoidance of soft tissue complications has to be a primary focus and factored into any surgical plan and that treatment based on the degree of soft tissue compromise yielded better results.^14-18 Finally, the ideal method of treatment is one that would achieve excellent articular reduction and stability while minimizing soft tissue compromise and devascularization of the fracture fragments.¹¹ Consequently, new tactics were utilized for the management of pilon fractures includind: delayed ORIF, limited ORIF, hybrid fixators, MIPO.

Helfet et al.¹⁹treated distal tibial fractures by MIPO in 2 stages. In the first stage they fixed the fibular fracture, if present, and applied an external fixator to the tibia. In the second stage they did a limited ORIF of the pilon fracture, and introduced subcutaneously a semitubular plate that they contoured manually to the shape of the distal tibia. They applied this protocol to 20 patients with 8 intraarticular and 12 open extraarticular distal tibial fractures. All their fractures united. Two fractures healed with >5º varus alignment and 2 fractures healed with >l0º recurvatum. No patient had a deep infection. The average range of motion in the ankle for dorsiflexion was 14º and plantar flexion averaged 42º.

Hazarika et al.²⁰ treated 20 patients who had open and closed distal tibia fractures with minimally invasive locking plate osteosynthesis (MILPO). Thirteen of their patients had preliminary external fixation. Average time to full weight bearing was 18.1 weeks (closed fractures), and 19.3 weeks (open fractures). Two fractures (one open – one closed) who had temporary external fixation were bone grafted from the iliac crest during the definitive MILPO procedure. They had two cases of wound breakdown and one case of wound infection, one case of implant failure, and one case of reflex sympathetic dystrophy. However, in their report, they did not comment on the functional results of the patients.

Our method of treatment did not involve preliminary external fixation as in the Helfet et al.'s¹⁹ and Hazarika et al.'s²⁰ series because we selected patients with apparently good soft tissue condition. Even in the 2 open fractures, both were grade I and other than the wound, the rest of the soft tissue envelope appeared well. Thus a single stage protocol was utilized thereby providing a shorter overall treatment time. Utilizing the MIPO technique as a single stage procedure further protected the soft tissue envelope by minimizing the surgical insult (large wound size, periosteal stripping) which might in itself lead to major complications (wound breakdown, infection, delayed or non-union). The MIPO technique was very useful in fractures with metaphyseal comminution as it avoided attempts at fixation of small comminuted fragment and a bridging fixation was done between the proximal and distal segments.

The plate we used was an anatomical prebent plate rather than a manually contoured semitubular plate that Helfet et al.¹⁹ used thus providing strong fixation as it allowed for insertion of 2 or 3 canellous 6.5 mm screws in the small distal segment while conforming to the anatomical features of the distal tibia. On the other hand, screws in the distal fragment could be freely placed in any direction in order to obtain good purchase in the small distal fragment contrary to the locked plates used by Hazarika et al.²⁰ with their fixed angle for screw insertion.

As regards functional outcome, our results are comparable to those of Helfet et al.¹⁹even though a large number of his patients had extra-articular fractures. This implies that in our series articular reconstruction was adequately done thus having a favourable functional outcome.

Conclusion

Minimally invasive plate osteosynthesis is a good and safe technique for treatment of distal tibial fractures without intra-articular comminution providing fracture healing, rapid functional recovery, and avoidance of major complications.

References

1. Muller ME, Nazarian S, Koch P. The AO Classification of Fracture, translated by J Schatzker. Toronto: Springer, 1988.
2. The  Orthopaedic  Trauma  Association Committee  for  Coding  and Classification: Fracture  and dislocation  compendium.  J Orthop Trauma 1996, 10 (suppl 1): v-ix,  56-60.
3. Ruedi TP, Allgower M. Fractures of the lower end of the tibia into the ankle joint. Injury. 1969; 1(2): 92-99.
4. Moll BN, Kerb B. Intra-articualr fractures of the distal tibia. Acta Orthop Scand. 1982; 53: 991-996.
5. McFerran MA, Smith SW, Boulas HJ, Schwartz HS. Complications encountered in the treatment of pilon fractures. J Orthop Trauma. 1992; 6: 195-200.
6. de Boer P and Metcalfe R. Mini-symposium: Tibial fractures, (iv) Pilon fractures of the tibia. Current Orthopaedics. 2003; 17, 190-199.
7. Probe R A. Minimally invasive fixation of tibial pilon fractures. Operative Techniques in Orthopaedics. 2001, 11, 3: 205-217.
8. Gustilo R B, and Anderson J T. Prevention of infection in the treatment of one thousand and twenty-five open fractures of long bones: retrospective and prospective analyses. J Bone Joint Surg [Am]. 1976; 58(4): 453-458.
9. Tscherne H, Gotzen L. Fractures with soft tissue injuries. Berlin: Springer Verlag, 1984.
10. Teeny SM, Wiss DA. Open reduction and internal fixation of tibial plafond fractures. Clin Orthop Relat Res. 1993; 292:108 --117.
11. Salton HL, Rush S, and Schuberth J. Tibial plafond fractures: Limited incision reduction with percutaneous fixation. J Foot  Ankle Surg. 2007; 46 (4): 261--269.
12. Ruedi TP. Fractures of the lower end of the tibia into the ankle joint: results 9 years after open reduction and internal fixation. Injury. 1973; 5: 130-- 134.
13. Ruedi TP, Allgower M. The operative treatment of intra-articular fractures of the lower end of the tibia. Clin Orthop Relat Res. 1979; 138: 105--110.
14. Watson JT, Moed BR, KargesDE*, Cramer KE*. Pilon fractures: treatment protocol based on severity of soft tissue injury. Clin Orthop Relat Res. 2000; 375: 78 --90.
15. Bone L, Stegemann P, McNamara K, Seibel R. External fixation of severely comminuted and open tibial pilon fractures. Clin Orthop Relat Res. 1993; 292: 101--107.
16. French B, Tornetta P. Hybrid external fixation of tibial pilon fractures. Foot Ankle Clin. 2000; 5: 853-- 871.
17. Pugh KJ, Wolinsky PR, McAndrew MP, Johnson KD. Tibial pilon fractures: a comparison of treatment methods. J Trauma. 1999; 47: 937--941.
18. Syed MA, Panchbhavi VK. Fixation of tibial pilon fractures with percutaneous cannulated screws. Injury. 2004; 35:284 --289.
19. Helfet DL, Shonnard PY, Levine D, Borrelli BJr. Minimally invasive plate osteosynthesis of distal fractures of the tibia. Injury. 1997; 28, Suppl. 1,  S.A42-S.A48.
20. Hazarika S, Chakravarthy J, and Cooper J. Minimally invasive locking plate osteosynthesis for fractures of the distal tibia – Results in 20 patients. Injury. 2006; 37, 877 – 887.