We have assessed 45 patients who had undergone anterior cruciate reconstruction by a modified MacIntosh-Jones method. The results, using standard knee scores and clinical ligament testing, correlated poorly with the patient's own opinion and with the functional result. However, measurement of proprioception in the knee correlated well with both function (r = 0.84) and with patient satisfaction (r = 0.9). This study indicates that proprioception, rather than the clinical excellence of the repair, is a major factor in the outcome of anterior cruciate ligament reconstruction.