Treatment of ruptures of the lateral ligament of the ankle.

In this study three forms of treatment for ruptures of the lateral ligament of the ankle have been compared with reference to their effect upon the final mechanical stability of the ankle, the duration of morbidity immediately after injury, and the incidence of complaints one year after injury. The three forms of treatment used were mobilisation, immobilisation for six weeks, and suture of the ligament followed by immobilisation. It is widely believed that persistent instability of the talus after a “ sprained ankle “ is caused by failure to distinguish between a rupture of the lateral ligament and a simple sprain at the time of injury, with the result that the former injury is treated by mobilisation, and the ligament fails to unite (Watson-Jones 1955). This view has led to the recommendation that ruptures should be treated by immobilisation. However, in the only reported study of ruptures of the lateral ligament treated by mobilisation and subsequently examined radiographically, mobilisation did not commonly lead to persistent mechanical instability (Hughes 1945); nor is it true that immobilisation always leads to healing. Ruth (1961) reported that of seventy-two patients treated by immobilisation, only two-thirds finally had mechanically stable angles, but that in contrast, final mechanical stability was invariable in a similar group of thirty-two patients treated by suture of the ligament and immobilisation. Findings such as these have led to the view that immobilisation, as well as mobilisation, may fail to guarantee final mechanical stability, but that this result can be guaranteed by suture of the ligament followed by immobilisation. The possible pathological background for this was suggested by Charnley (1950) when he wrote “ one cannot help feeling that these ligaments [ruptured lateral ligaments] will heal without fixation if the ends are not grossly separated, whereas they will fail to heal if grossly separated, even if fixed in plaster.” Suture guarantees approximation and hence “ healing “ even when the ruptured ligament is originally “ grossly separated.” There is no information in the literature upon which to base an estimate of the average duration of the early disability after rupture of the lateral ligament of the ankle, nor is there information concerning the effect of various forms of treatment upon this time interval. No direct comparison of the late symptomatic results of the three forms of treatment for ruptures of the lateral ligament studied here has been reported. Such descriptions as have been published have omitted a description of the symptomatic state of the treated ankles before injury, so that it is impossible to be certain that the final disability did not antedate the injury described. Hughes (1945) found that the late symptomatic results of mobilisation were good, but many surgeons consider them to be unsatisfactory-a view based upon the fact that mobilisation is thought to result in mechanical instability and that this in turn causes the foot to “ give way.” Against immobilisation, Ruth (1961) found that 58 per cent of patients so treated had persistent complaints two years later, and Wiles (1959) stated that immobilised ank1es remained stiff for long periods. Good long-term results, however, have been said to follow iminobilisation (Watson-Jones 1955). Ruth (1961) reported that 90 per cent of his patients had “normal function or a very good result” two years after primary suture. However, less than half of the patients Ruth followed were completely symptom-free.