Is it possible to achieve multiplanar correction of complex deformities around the knee in children and adolescents using a monolateral external fixator?

Purpose: To present the technique of correction of multiplanar deformities around the knee in children and adolescents using the monolateral external fixator. Also, to evaluate the results of the technique regarding radiological correction, time to union, and possible complications.

Methods: A total of 29 patients (47 limbs) were prospectively included in the study (14 males and 15 females). Their median age was 13 years (range, 7-17). All patients had at least a 2-plane deformity around the knee which was corrected using a monolateral external fixator. The primary outcome measure was deformity correction (correction of mechanical axis deviation (MAD) in both the coronal and sagittal planes with correction of rotational deformities). The secondary outcome measures included bony union, radiographic, and functional results (assessed by using the Association for the Study and Application of the Method of Ilizarov (ASAMI) score).

Results: The median pre-operative MAD improved from 6.3 to 0.4 cm post-operatively. According to the ASAMI scoring system, the radiographic scoring was excellent in all cases (100%), and the functional scoring was excellent in 22 cases (89.7%) and good in three cases (10.3%).

Conclusion: The simple monolateral fixator can be an effective tool for multiplanar correction of complex deformities around the knee without limb length discrepancy.