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

Abstract

Objective: To study incidence of tibial tunnel widening and its functional correlation in patients operated with ACL reconstruction with four fold hamstring tendon autograft. To evaluate radiologically and clinically tunnel widening when tibial side of graft is fixed with suture disc or interference screw and to study type of tunnel widening (cavity type, cone type and line type) and its functional correlation. Introduction: Arthroscopic ACL reconstruction is most commonly done ligament reconstruction surgery in orthopaedic with gratifying results. However, it is also associated with complications. Tunnel widening (TW) as one of the complications has been topic of discussion in orthopaedic literature recently. Type of graft fixation in tibia has been considered as cause of tunnel widening. We compared TW in grafts fixed with suture disc and interference screw, evaluated type of tunnel widening in tibia and its correlation in terms of radiology and function. Methodology: A cohort of 30 patients operated with arthroscopic ACL reconstruction were evaluated over a period of three years. Patients were divided between suture disc group and interference screw group for tibial fixation and femoral fixation was kept same in both the groups i.e. suspensory. We assessed amount of tunnel widening in tibia with radiographs and CT scan at 3 months 6 months and 12 months, divided TW into cavity type, cone type and line type. We tried to correlate amount of TW with type of tibial fixation and its functional score. We also tried to correlate type of TW and functional score. Results: Amount of TTW was more with interference screw group than suture disc group at 12 months. Lysholm score was almost equal in both the groups. Type of tunnel widening: cavity type is more common 53 %, followed by cone type 26% and then line type 21 %. TTW was highest i.e. 12.11mm in cavity type, followed by 12.04 in cone type and 11.72 in line type. Functional score was almost similar in all types. Conclusion: Both the groups i.e. suture disc and interference group had considerable tunnel widening but the difference between them is negligible to conclude superiority of on over the other. Functional score is similar in both the groups. Regarding type of tibial tunnel widening, cavity type TTW is most common (53%), followed by cone type (26%) and least common is line type widening (21 %). Maximum tunnel widening is in cavity type and if it's less than 12 mm then functional score is good in those patients. There is no significant correlation between the type of TTW and clinical stability and functional scores. But it has surgical implications as more tunnel widening leaves lesser bone bed for revision ACL reconstruction.