Summary

Findings from 4-year, ongoing observation of patients who have undergone an anatomical - ribbon ACL reconstruction.

Abstract

Introduction

The paradigm of anterior cruciate ligament reconstruction (ACL-R) is undergoing contant changes.There are several techniques used around the world, stirring much discussion on which approach is optimal for patients' recovery and long-term outcomes.

Methods

Between 2018 and 2022, 131 patients (mean age 41 years) underwent a "ribbon" ACL-R (99 primary and 32 revisions) with a central band of the quadriceps femoris (QF) tendon autograft. In 42 cases a pre-op CT scan was done. All patients had pre- and post-op MRI scans. Follow-up included physical examination at 3, 6, and 12 weeks and subsequently every 3 months up to 1 year, every 6 months after that. Follow-up MRIs were done at every 3 months post-op for a year, and then every 6 months. In 92 cases post-op CT scans were done (post-op protocol was extended by a routine CT after a year), to assess tunnel placement, tibial and femoral tunnel widening, bone cyst formation, posterolateral tibia correction). Physical examination included: ROM, oedema/swelling, pain (palpation) and instability evaluation (Lachman and anterior drawer. tests). On MRIs graft maturation (signal), bone cysts/oedema presence, soft tissues healing stage, intra-articular scar formation, and tibia subluxation were evaluated.

Results

In all cases there were no donor-site morbidity; pain at donor-site; infections; and spontaneous re-ruptures were noted. 2 traumatic re-ruptures have been recorded to date. All primary patients returned to their expected level of daily activity at 2-3 weeks post-op and to sports/physical activity at 6 months on the average (4 - 12 months). Overall patient-reported satisfaction at 9 months post-op was "very good" to "excellent".
Structure-wise good graft ingrowth and remodelling was observed on MRIs at 9 months on the average with no post-op aterior tibia subluxation (separate study conducted). On CTs there was no tunnel malpositioning or significant widening observed at 3 months follow-up.
Functionally, there was no recurrent instability confirmed during physical examinations. Full knee flexion and extension at 6 weeks post-op was achieved in ca. 92% of cases (in primary cases, without menisci suturing), along with symmetrical stability in both lower limbs (negative Lachman and anterior drawer tests). Through monitored physical therapy, overall function similar to the contralateral leg achieved at 4 months on the average and good to very good QF contraction at 6 months post-op with no donor site morbidities.

Conclusions

Recent anatomical research indicates that the ACL’s midsubstance is in fact flat. Still, the way the ribbon-like structure behaves while knee flexion and extension can create an illusion of a double-bundle structure, therefore, we can speak of "functional bundles", but not structural ones. The recently-established "ribbon" ACL-R takes into account both graft’s and tunnels’ anatomical shape and positioning, allowing for a truly anatomical reconstruction, showing very promising long-term outcomes, especially with regard to the graft incorporation failure rate, allowing patients to safely return to their normal lifestyle in relatively short time.