Correction of Knee Angular Deformities in Growing Children by Percutaneous Hemiepiphysiodesis Using Transphyseal Screws

Pediatric angular deformities of the knees are very common musculoskeletal anatomic variations. These deformities may lead to gait disturbance, leg length discrepancy therefore surgical correction is often recommended. Hemiepiphysiodesis using staples or tension band plates has been commonly used to correct knee angular deformities in growing children. Alternatively, a percutaneous screw inserted crosswise could be used. The incision & exposure in the latter method are minimal and it is already commonly used in ankle angular deformity correction. We hypothesized that hemiepiphysiodesis using percutaneous screws would be as effective as tension band plating for guided correction of knee angular deformity with respect to the degree of correction and complication rates. We compared the radiographic outcomes of growing children undergoing hemiepiphysiodesis using either percutaneous screws (13 children, 21 knees) or tension band plating (11 children, 16 knees). Preliminary results showed no significant differences (p>0.05) postoperatively in mechanical axis deviation (MAD) and joint line convergence angle (JLCA) between the methods. Hemiepiphysiodesis using percutaneous screws or using tension band plating successfully corrected the MAD from a preoperative average of 28mm to a post operative average of 7.3mm using plating and 3mm using screws. Furthermore, average JLCA significantly improved from a preoperative 2.2° to a postoperative average 1.5°. Complications included difficulty in hardware removal, rebound effect and the need for additional surgery. Based on these highly promising results, upon completion of this study and the accumulation of more evidence we believe that percutaneous hemiepiphysiodesis using transphyseal screws could be an attractive alternative to plating.