Post-operative outcomes of transphyseal anterior cruciate ligament reconstruction in skeletally immature patients using round-headed cannulated interference screw fixation.

Abstract

Anterior cruciate ligament (ACL) reconstruction in skeletally immature populations remains a controversial surgical procedure owing to the concerns over iatrogenic growth arrest of the distal femoral or proximal tibial physis. The increasing presentation to orthopaedic surgeons, particularly in young athletes and physically active individuals, warrants a consensus opinion on a safe and effective surgical technique to help guide evidence-based clinical practice. Previous research has reported the effectiveness and safety of primary graft reconstruction and transphyseal ACL reconstruction with skeletally immature individuals however the optimal fixation method remains ambiguous.The current thesis aimed to assess post-operative outcomes in skeletally immature patients who had undergone transphyseal ACL reconstruction using round-headed cannulated interference (RCI) screw fixation in both the femoral and tibial tunnels. Thirty-one skeletally immature patients (21 males &10 females) with a mean age of 15.16 years (range 12 - 16 years) at surgery underwent autologous ipsilateral 4-strand hamstring ACL reconstruction using interference screw fixation in both the femoral and tibial tunnels. The primary outcome measure was leg-length and alignment evaluated by standardised x-ray investigations in the sagittal and coronal planes to examine for iatrogenic growth arrest of the physis through radiological and clinical analysis. Secondary outcome measures included knee specific muscle strength, function, and subjective patient evaluation of their physical activity, function, and pain levels. All outcomes measures were assessed following skeletal maturity, with a minimum 2-year post-operative follow-up.Analysis of long-leg alignment and lateral radiographs found no statistically significant differences (p > 0.05) between the operative and non-operative knees, and no evidence of bone growth arrest in either the coronal or sagittal planes. Self-reported outcome measurements reported that patients remained active in the post-operative period without significant impairment despite a slight reduction in the level of competition which appears to be multi-factorial. Isometric dynamometry results demonstrated statistically significant decreased hamstring strength on the operative side compared to the non-operative side (p < 0.05), with no statistical difference in functional activities such as maximum standing long and vertical jump distance.The findings from this study suggest that transphyseal ACL reconstruction is a safe and effective surgical technique to restore stability of the knee joint in late stage skeletally immature adolescent patients. In the short to medium term, such stabilisation of the knee following ACL repair has been shown to help reduce the incidence of meniscal and chondral damage as secondary pathologies. This study also demonstrated that graft interposition using interference screws in both the femur and tibia is a reliable fixation method without adverse outcome. Utilising autologous hamstring tendon grafts reduces isometric hamstring strength, however this does not appear to impact significantly on functional tasks such as maximal standing long and vertical jump performance. This later finding suggests a compensatory phenomenon is involved in these more “global” functions of the lower limb musculature. Dedicated multi-centre prospective studies will serve to provide further data on transphyseal ACL reconstruction using interference screw fixation in skeletally immature patients in relation to the “gold standard” method in paediatric orthopaedic surgery.