The Impact of Transphyseal Anterior Cruciate Ligament Reconstruction on Lower Extremity Growth and Alignment.

PURPOSE: To evaluate the effect of transphyseal anterior cruciate ligament (ACL) reconstruction on lower extremity radiographic growth and alignment.

METHODS

We retrospectively reviewed patients who underwent transphyseal ACL reconstruction and were followed to skeletal maturity or at least 2 years, with the nonoperative limb used as an internal control. Changes in coronal plane alignments and tibial slope of the operative limb were compared with a Wilcoxon test. Associations among sex, tunnel, and graft characteristics and failure; changes in coronal plane measures and tunnel size; and tunnel angles and the development of deformity were examined by χ-square and correlation coefficients.

RESULTS

Fifty-nine patients (41 boys and 18 girls) underwent surgery at a mean age of 12.5 years (range, 6.8-16.0 years). There were differences in changes in the mechanical lateral distal femoral angle comparing operative and nonoperative limbs (decreased 1.1° in girls and 1.9° in boys ≤13 years of age, P = .0008 and .025, respectively) and in changes in tibial slope of the operative limb (decreased 2.1° in male patients >13 years, P = .012). No patient developed a new limb length difference >1 cm. Two boys were treated for deformities. Eight additional patients developed >5° difference in alignment for a rate of radiologic deformity of 10 of 59 or 17%. Neither graft failure nor the presence of deformity was associated with sex, tunnel size, mode of femoral tunnel positioning, inclination of tunnels, or the use of allograft.

CONCLUSIONS

Radiographically evident limb deformities following transphyseal ACL reconstruction occurred at a rate of 17%, although these deformities were clinically evident in only 5% of patients. Tunnels intersecting physes near cortical margins may increase the risk of developing deformity. Regular follow-up should include alignment radiographs to detect deformities despite the clinical appearance of neutral limb alignment.

LEVEL OF EVIDENCE: Level III, case-control study.