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The Blackburn Foot and Ankle Hyperbook  
Evidence based education in foot and ankle surgery
  ORIF versus MUA of displaced ankle fractures

Closed reduction of displaced ankle fractures was the standard treatment for many years until Cedell, Danis and others began to promote internal fixation. Cedell’s method was cerclage wiring with staple stabilisation of the syndesmosis and this non-rigid method was popular in Scandinavia until relatively recently.

Early internal fixation techniques emphasised stabilisation of the medial malleolus with screws, believing that the lateral malleolus contributed little to ankle stability. In 1977, Yablon published a group of biomechanical and clinical observations which led him to the conclusion that “the talus follows the lateral malleolus” and that the key manoeuvre in internal fixation of the ankle was accurate reduction and stable fixation of the lateral malleolus.

In addition, Ramsey and Hamilton (1976) studied the effect of lateral displacement of the talus on contact area in the ankle.

For the next 15 years Yablon’s work guided surgical methods. In the early 1990s improved experimental models allowed a re-appraisal of the biomechanics of ankle fractures. Measurements of unconstrained, axially loaded ankle motion after the creation of ankle fractures and malunions showed that, in fact, the talus remained congruent with the mortise even after the creation of unstable lateral malleolar fractures or malunions with up to 6mm of lateral displacement, provided that the deltoid ligament remained intact and any medial malleolar fracture was fixed. Loss of deep deltoid function, however, led to significant alterations in ankle kinematics, especially in plantarflexion. Lateral malleolar displacement did, in these experiments, alter peak pressures and contact characteristics in the ankle, but by much less than that predicted by Ramsey and Hamilton.

These biomechanical models still do not reproduce the clinical situation fully, and further work may revise our understanding of ankle pathomechanics. However, currently more attention is drawn to the medial side than previously, but without neglecting the desirability of lateral malleolar reduction. Perfect reduction of the lateral malleolus is no longer considered necessary for tibiotalar congruency.

It is in the above context that the value of internal fixation of ankle fractures should be assessed. Several moderate and large case series have been published, and these have been taken together with the work of Ramsey and Hamilton and Yablon to make strong recommendations for internal fixation of displaced ankle fractures. However, comparison of closed reduction and internal fixation requires randomised controlled trials. Only 3 of these have been published in general populations. It is interesting to note that they were published, within a year of each other, in the mid-1980s and that no further work in a general population has been reported for 16 years, implying that the orthopaedic community viewed this as a closed question. However, this conclusion does not seem to be warranted by the data.

Bauer et al (1985) randomised 111 displaced Weber A or B fractures to ORIF by AO methods or to closed reduction and casting. All were then managed in a BK NWB cast for 6 weeks. 7 patients randomised to closed reduction could not be reduced and underwent ORIF, but analysis was on the basis of intention-to-treat. Patients were reviewed at 6 weeks (probably all) and 100 were reviewed at 6-8 years. Early results are said to be better in the operated group but there are no functional results to support this and it may just mean that the operated group had better reductions radiographically. There was no difference in outcome at 6-8 years. The patients who failed closed reduction had poorer results; they may have been more severe fractures.

Phillips et al (1985) reported a composite trial in which 142 patients with displaced SER4 or PER ankle fractures (most of which would probably be AO B) first underwent attempted closed reduction. If this produced an acceptable result they were randomised to AO internal fixation or closed casting. Bothe groups were treated in long leg casts for 10 weeks. Failures of closed reduction were randomised to AO or medial malleolar fixation, but the numbers in this group were so small that no conclusions can be drawn. 96 were randomised to ORIF or casting and 49 of these were followed up at 1.5-6 years. A composite outcome score was used with sections for function, radiography and arthritis – fortunately, the authors report each component of the score. The total scores in the ORIF group were significantly better at final review, BUT when each component of the score was analysed separately, only the radiographic score was better. In other words (and contrary to the “headline result”), the functional result was the same in the closed reduction group although the reduction in this group was poorer.

Rowley et al (1986) reported 42 displaced ankle fractures, mostly Weber B, randomised to AO ORIF or closed reduction and casting. BK casts were used in each group, with weightbearing as tolerated, and retained for 6 weeks. Final evaluation was at 20 weeks and the outcome measures were range of ankle movement and foot progression angle – there was no functional score. In the non-operated group the patients started weightbearing earlier and there was earlier recovery of range of movement and foot progression angle. It is difficult to draw reliable conclusions from this study because of the small number of patients, short follow-up and non-specific outcome measures.

None of these studies showed any long-term advantage from ORIF. Bauer’s series may have shown faster recovery of function, but the data do not clearly support this and Rowley and Duckworth’s data point the other way.

These studies should not be taken to show that ORIF is unnecessary. For one thing, the post-operative management was restrictive (only Rowley et al allowed early weightbearing and none allowed early movement to surgically treated patients). Outcome measures were non-standardised and there was significant loss to follow-up in Phillips’ series. In addition, there were patients in each series (10-30%) who could not be managed closed and required ORIF. However, this data would suggest that if the talus can be maintained under the tibia closed reduction and casting is an acceptable method of treatment. ORIF would be indicated for:

  • unstable fractures
  • open fractures
  • multiple injuries
  • patients in whom ORIF and early functional weightbearing management would be expected to convey an advantage

References

  • Cedell C-A. Supination-outward rotation injuries of the ankle. AOS 1967; supp 110
  • Yablon IG et al. The key role of the lateral malleolus in displaced fractures of the ankle. JBJS 1977; 59A:169-73
  • Ramsey PL, Hamilton W. Changes in tibiotalar area of contact caused by lateral talar shift. JBJS 1976; 58A:356-7
  • Bauer M et al. Malleolar fractures: nonoperative versus operative treatment. CORR 1985; 199:17-27
  • Phillips WA et al. A prospective, randomised study of the management of severe ankle fractures. JBJS 1985; 67A:67-78
  • Rowley DI et al. A prospective trial comparing operative and manipulative treatment of ankle fractures. JBJS 1986; 68B:610-3
  • Yde J, Kristensen K. Ankle fractures: supination-eversion fractures of stage IV. AOS 1980; 51:981-90