Summary
Multicentric cohort study to compare the knee stability, clinical/radiological outcomes and failure rates of isolated ACLR versus ACLR + MLLET in pediatric patients at mid-term follow up
Abstract
Background
Pediatric patients undergoing ACLR have a high risk of re-rupture. Recent literature has reported that the combination of a modified Lemaire lateral extra-articular tenodesis (MLLET) and ACLR improves short term outcomes in this specific population. However, the advantages, complications or possibility of growth disturbance because of the addiction of a MLLET in a skeletally immature population at mid-term are still unknown.
PURPOSE/HYPOTHESIS
To compare the knee stability, clinical/radiological outcomes and failure rates of isolated ACLR versus ACLR + MLLET in pediatric patients at mid-term follow up. The hypothesis was that combined procedures would improve knee stability, clinical outcomes and reduce the failure rate over years, without determining growth disturbance or lateral compartment degeneration.
Methods
A multicentric cohort study involving 3 centers was conducted to evaluate pediatric patients with a maximum bone age of 16 years (boys) and 14 years (girls), who had undergone primary ACLR using a physeal-sparing femoral tunnel drilling technique. A minimum 5-year follow-up was required. Patients were divided into 2 groups. Group 1: isolated ACL-R; Group 2: ACL-R + MLLET. Group 1 was a historical control cohort of patients, whereas group 2 was prospectively enrolled. All the patients were evaluated using the Pedi-IKDC subjective score and the Pedi-FABS score. Anteroposterior knee stability was measured using the KT-1000. Patients also underwent a standardized radiological protocol to evaluate leg-length discrepancies, axial deviation, and degenerative signs preoperatively and at last follow-up.
Results
This study included 66 patients with an anatomic hybrid ACLR using an autologous 4-strand hamstring graft. Group 1: 34 patients (mean age, 13.5 +/- 1.2 years), mean follow up 62.2 +/- 2.6 months. Group 2: 32 patients (mean age, 13.8 +/- 1.4 years), mean follow up 61.9 +/- 1.8 months (P = 0.661).
The clinical outcome scores showed no difference between groups (Pedi-IKDC, P= 0.089 and Pedi-FABS, P= 0.095). However, patients in group 2 had better objective AP stability measured using a KT-1000 (2.1 +/- 1.7 mm in group 1 vs 0.9 +/- 0.4 mm in group 2; P= 0.029).
Two cases of leg-length discrepancies were found in group 1 (1 case of 4mm femur hypermetria and 1 case of 3mm femur hypometria) and 2 cases of hypermetria (4mm femur) in group 2 (P = .991).
Four patients displayed an increased valgus deformity on the operated limb at last follow-up (2 in group 1 (2º and 3,5º) and 2 in group 2 (3º and 4º), P= 0.884). No degenerative changes were detected.
In Group 1 eight ACL failure (23.5%) were detected, 7 cases of complete ACL tear verified by MRI and 1 case of clinical failure (side-to-side KT1000 difference > 5mm associated with subjective feeling of giving-way). In Group 2 three ACL failure (9,4%), 2 verified by MRI and 1 clinical failure. The difference between groups was significative (P=0.027).
Conclusion
Combined autologous 4-strand hamstring ACLR and LET in pediatric population reduced the cumulative failure rate and improved objective stability at mid-term follow up. No significant difference was found between the 2 groups in terms of patient-reported outcomes