Comparison of Tibial Tunnel Enlargement after Anterior Cruciate Ligament Reconstruction Using Patellar Tendon Autograft or Allograft

Abstract

This retrospective study was designed to compare tibial tunnel enlargement in patients with autograft or allograft anterior cruciate ligament reconstructions. The changes were related to position of the tibial tunnel and clinical outcome. Twenty-six patients with autograft reconstructions and 41 with allograft reconstructions were studied at a mean follow-up of 59 months (range, 41 to 84) after surgery. The average tunnel enlargement on the anteroposterior view was 2.2 mm (SD, 2.5) for autografts and 2.8 mm (SD, 2.1) for allografts. On the lateral view, the tunnel enlargement was 2.6 mm (SD, 2.4) and 3.4 mm (SD, 2.6) for autografts and allografts, respectively. No significant differences were found between the autograft and allograft groups. A trend was found in the correlation between the position of the tibial tunnel and the tunnel enlargement: more anteriorly placed tunnels had more enlargement. The changes in tunnel diameter did not relate to knee functional score or laxity. There was a significant correlation between malposition of the tibial tunnel and poor clinical scores. A significant negative correlation was found between postoperative follow-up time and tunnel enlargement in both groups. We conclude that placement of the tibial tunnel is a determining factor in tibial tunnel enlargement and clinical knee scores after anterior cruciate ligament replacement with an autograft or allograft. Tunnel enlargement tends to be less at a longer postoperative follow-up.

Influence of meniscal repair versus meniscectomy on ACL reconstruction in terms of knee stability and radiological imaging

“…Webster et al found significant correlation between tibial tunnel enlargement and anterior knee laxity [8] . Bone tunnel widening is more associated with many factors like type of graft, graft fixation systems elastic or rigid, single or double bundle fixation, and aggressive rehabilitation [18] . The biological theory states that release of TNF, interleukins, and nitric oxide present in the synovial fluid can cause osteolysis.…”

“…The biological theory states that release of TNF, interleukins, and nitric oxide present in the synovial fluid can cause osteolysis. The mechanical reasons for tunnel widening are graft tunnel micro motion in suspensory fixation, stress shielding proximal to the interference screw and nonantomical graft fixation [18,19,20] . As menisci along with cruciate ligaments also has important role in biomechanical stability, we have tried to evaluate incidence of tunnel widening and knee instability after ACL reconstruction and compare them in two groups: those with meniscal repair and those with without repair.…”

Radiological and clinical evaluation amongst types of tibial tunnel widening and choice of graft fixation implants in ACL reconstruction

“…In our cases, we had maintained standard protocol of rehabilitation of 2 weeks immobilization in extension followed by gradual knee bending up to 90 degree and full weight bearing at the end of one month. We had used transportal technique to drill the femoral tunnels to place the footprint as anatomical as possible as it was found that non anatomical or anterior tibial tunnel placement was found to have higher tunnel enlargement due to mechanical stress on the graft [20] . The etiology of tunnel enlargement is currently unknown.…”

“…Possible factors responsible for bone resorption include mechanical theory which states that there is a micromotion of the graft relative to the tunnel wall which causes synovial fluid bathing of the graft, leading to an inflammatory response in the tunnel. Also stress shielding of the tunnel wall proximal to the interference screw can cause weakening of the bone [6,20,21] Biological factors include nonspecific inflammatory response cells, heat necrosis due to drilling, cytokine response like TNF, interleukin-6, nitric oxide from the synovial fluid and foreign body response to allograft [22,23] There are different patterns of osteolysis at tibial tunnel described by Peyrache where patellar tendon bone graft was fixed with screw. These are cone type, cavity type and line type [7] We evaluated similar changes in our patients and tried to evaluate its clinical and functional correlation.…”

Como mensurar o alargamento dos túneis ósseos na cirurgia de reconstrução do ligamento cruzado anterior? descrição de uma técnica

“…Taking into consideration the distance from the fixation to the joint surface, the rates range from 0% to 23% for grafts subjected to anatomical fixation (4) and from 47% to 73.9% for those fixed at a distance from the joint surface (3) . Although many studies have reported occurrences of enlargement, none have proven that it is clinically significant or that it is related to surgical failure rates (1,4,5,6) . Its mechanism is also not fully understood.…”