Growth plate disturbance after transphyseal reconstruction of the anterior cruciate ligament in skeletally immature adolescent patients: an MR imaging study.

BACKGROUND: There are concerns of potential growth disturbance after transphyseal reconstruction of the anterior cruciate ligament in skeletally immature patients. The authors used magnetic resonance (MR) imaging to evaluate growth disturbance and associated physeal abnormalities after index surgery.

METHODS: We retrospectively reviewed the follow-up MR imaging studies of 43 patients who underwent transphyseal reconstruction of the anterior cruciate ligament using a soft-tissue graft at the mean age of 14.8 years (range, 12.4 to 16.5 y). Mean time from surgery to follow-up MR imaging was 16 months (range, 6 to 36 mo). Bone tunnel to growth plate cross-sectional area ratios were calculated as percentages. Focal growth disturbances were assessed in the follow-up MR images in terms of physeal tenting, the presence of a focal bone bridge, an asymmetric growth arrest line of Harris, and metaphyseal extension of physeal cartilage. Physeal angles with respect to the longitudinal axes of the corresponding bones were measured in preoperative MR images and compared with those measured in follow-up images. Premature physeal closure was assessed using the proximal fibular growth plate as an internal control. Clinically, growth disturbances were assessed with physical examinations regarding standing pelvic heights and alignments of the lower extremities.

RESULTS: The bone tunnel to growth plate ratio was < 3% for proximal tibia and distal femur. A focal bone bridge was observed in 5 patients-4 at the tibial physis and 1 at the femoral physis. Physeal angles did not change significantly during follow-up in either the coronal or sagittal plane. Earlier physeal closure than other physes was observed in 2 proximal tibiae. Clinically, there were no perceived growth disturbances.

CONCLUSIONS: MR imaging revealed that focal physeal disruption developed after index procedure in 5 of 43 adolescent patients (11.6%) without a perceived clinical growth disturbance. The results suggest that transphyseal reconstruction of the anterior cruciate ligament may not be a benign procedure that can be applied safely to younger children with substantial growth remaining.

LEVEL OF EVIDENCE: Retrospective Case Series, Therapeutic Level IV.