External fixator for treatment of the sub-acute and chronic multi-ligament-injured knee

To assess whether the use of an articulated external fixator provides improvements in the mobility, stability and subjective function of patients undergoing ligament reconstruction.

Thirty-three patients with sub-acute and chronic knee dislocation were subjected to multi-ligament reconstruction surgery. These patients were randomly allocated to two groups for immobilization after reconstruction: group 0-control (18 patients), with rigid knee bracing, and group 1-articulated external fixator (15 patients). The stability of the reconstructed ligaments was assessed after at least 14 months (26.6-month average) postoperatively by physical examination. Deficit of extension and flexion was measured in relation to the unaffected contralateral knee, and the Lysholm knee scoring scale questionnaire was applied.

There was no difference in the assessment of joint stability between the groups. In group 1, patients showed less flexion deficit (4.8° ± 5.4° vs. 18.2° ± 14.8°, p < 0.05), and the percentage of patients with a flexion deficit of 5° or less were higher compared with group 0 (64 vs. 18 %, p < 0.05). There was no difference between groups in relation to extension loss. Group 1 also presented better Lysholm scores, with 73 % of patients rated as excellent or good compared with 35 % in group 0 (p < 0.05).

Compared with the control rehabilitation protocol with rigid knee bracing in extension, the use of an articulated external fixator in the treatment of chronic multi-ligament-injured knees provided the same ligament stability, better final range of motion and improved Lysholm score. Patients presenting with chronic multi-ligament instability should be considered for articulated external fixation to supplement reconstruction procedures.

Randomized controlled trial, Level I.