General management after ankle fracture fixation is noncontroversial:
- reduction of swelling
- wound care
Traditional management would then be 6 weeks in a below-knee cast with varying amounts of weightbearing. Older series have used up to 12 weeks in a long leg cast.
The issues to be answered include:
- Does early mobilisation of the ankle followed by a period of casting produce better movement after removal of the cast? This was a popular method of post-op care 20-30 years ago but an RCT by Dogra and Rangan (1999) showed no advantage over simple casting.
- Does weightbearing affect the outcome, alone or in combination with mobilisation?
- Does protected mobilisation affect the outcome, alone or in combination with weightbearing?
Several small RCTs have addressed the latter two issues. There is no evidence that either weightbearing or early movement adversely affect outcome, and some evidence that they may have a small beneficial effect in the short to medium term. In addition, patients tend to prefer functional treatment rather than NWB casting. The non-casted patients in these trials were protected by ankle bracing or NWB exercise, rather than being left completely free. In practice we find that most patients prefer the support of an ankle brace which fits a trainer and allows weightbearing and ankle movement. However, Lehtonen et al (2003) reported a higher rate of wound problems in patients randomised to an Aircast brace instead of a cast. Application of the brace after wound healing seems to avoid this problem. Thomas (2009) carried out a systematic review of early mobilisation after ankle fracture fixation, reviewing nine trials. Patients who had early movement had better range of movement, better Olerud-Molander scores and earlier return to work than patients treated in plaster. However, by 1 year the benefit had diappeared.
Nilsson (2009) randomised patients to simple advice and physio as decided by the surgeon, or to a specific ankle rehabilitation programme for 12 weeks. In patients under 40, Olerud-Molander scores, plantar flexion power and dorsiflexion power were better in those who had the programme, althoug it is unclear how long after the programme this effect continued.
Currently there seems no reason to restrict weightbearing or mobilisation unless there are specific reasons to do so. Such reasons might include poor bone quality with limited stability of fixation, or patient compliance issues. Our default practice is to splint the ankle in a backslab or BKW cast until the wound has healed and then to mobilise in an ankle brace with weightbearing as tolerated.