Changes in joint position sense after conservatively treated chronic lateral ankle instability.

Improvement of ankle proprioception through physiotherapy (a.k.a. proprioceptive training) is a widely accepted conservative treatment modality of chronic functional lateral ankle instability. Clinical studies provided controversial data on its proprioceptive effect. Aim of this study was to gain evidence on the efficacy of proprioceptive training on ankle joint position sense. Ten patients (five males and five females, aged 23.3+/-5.4 years) were treated conservatively for chronic lateral ankle instability with a special training programme over 6 weeks. For the assessment of joint position sense we used the slope-box test, first applied and described by Robbins et al. (Br J Sports Med 29:242-247, 1995). The test was performed before the start and after the end of the training programme, measuring joint position sense on 11 different slope amplitudes in four directions (anterior, posterior, lateral and medial) in random order each on both ankles. Comparisons were made between pre- and post-training results as well as versus a control-group of ten healthy athletes. Overall the proprioceptive sensory function of the studied group has improved, but this improvement was not significant in all directions. Only two patients have shown significant improvement of joint position sense in all directions (mean estimate error improvement: 2.47 degrees ), while conservative treatment was partially successful in five others (mean estimate error improvement: 0.73 degrees ). The follow-up results of these seven patients were comparable with the values measured in the control-group. Three patients did not show any improvements (mean estimate error improvement: -0.55 degrees ) (overall difference between improving and non-improving patients: P<0.0001). Mean absolute estimate error profiles of the seven improving patients became similar to the profiles of healthy athletes, while these changes could not be observed in the case of the three non-improving participants. Proprioceptive rehabilitation programme can be an effective method in order to improve impaired joint position sense function. After 6 weeks non-responding patients can be well identified, and considered for other treatment modalities. The determination of the effective length of the programme however needs further evaluation. Still, changes in the proprioceptive sensory function of the ankle plantarflectors indicate the preventive effect of the training programme. Furthermore, our results support the theory of simultaneous function of different mechanoreceptor-systems.