Comparison of Bone-Patella Tendon-Bone and Four-Strand Hamstring Tendon Grafts for Anterior Cruciate Ligament Reconstruction: A Prospective Study

Introduction

To date, the proper choice of graft for anterior cruciate ligament (ACL) reconstruction remains a matter of conflict. We aimed to compare the clinical and functional outcomes of the two most commonly utilized autografts, bone-patella tendon-bone (BPTB) and four-strand hamstring tendon (HT) graft, at 6 and 12 months after surgery.

Methods

In a prospective randomized study, we included a total of 60 patients undergoing ACL reconstruction, thirty in BPTB and thirty in HT group. All patients were amateur athletes and were evaluated at 6 and12 months after surgery for: (a)postoperativefunctionality of the operated knee by the Tegner, the Lysholm and the International Knee Documentation Committee (IKDC) scoring scales, (b) anterior cruciate ligament (ACL) instability of the operated knee compared to the healthy contralateral knee by the KT-1000 arthrometer and (c) theextension and flexion muscle strength of the operated knee by a CYBEXisokinetic dynamometer. 

Results

Patients in the two groups did not differ regarding demographics, and pre-injury functionality status. Significantly more patients in the HT group (n=6) compared to the BPTB group (n=1) experienced ACL re-rupture and underwent revision surgery before follow-up end (p=0.044). All patients, regardless of graft, showed significant improvement within each group of functional assessments by Lysholm, Tegner and IKDC scores, as well as of Cybex measurements -with an increase of peak torque at 60° extension and 180°extension and 60° flexion and 180° flexion- at 12 months compared to 6 months follow-up (p<0.05). However, there was no difference between the two groups regarding knee function improvement or extension measurements neither at 6 nor 12 months. Contrarily, the BPTB graft group had higher values of peak torque (Nm) at 60° and 180° flexion compared to the HT group, both at 6 (p=0.014 and 0.029, respectively) and 12 months (p=0.033 and 0.030, respectively). Postoperative stability was similar between the two groups at 12 months (p=0.519).

Conclusion

Both BPTB and HT grafts present with benefits and drawbacks and remain viable autograft options for primary ACL reconstruction as each has, although HT grafts seem to be more susceptible to re-rupture. The graft selection should be based on the needs and activities of each patient. 

A Systematic Approach for Stronger Documentation of Anterior Cruciate Ligament Graft Choice

Numerous studies have focused on determining the optimal choice between the two most used anterior cruciate ligament (ACL) reconstruction autografts. In order to address this matter, we performed a systematic review of every meta-analysis published on the PubMed platform between 2001 and 2020, comparing the functional outcomes, the static stability parameters, as well as the postoperative and long-term complications of the patellar tendon (BPTB) autograft and hamstrings (HT). We retrieved a total of 26 meta-analyses that met our criteria, and the characteristics and outcomes of every meta-analysis, as well as subgroup analysis regarding the type of the study design, number of strands of HT autograft, and fixation method, were extensively recorded. The majority of the meta-analyses showed that there were no significant differences between BPTB and HT in terms of functional outcomes and static stability parameters while HT autografts seem to be superior to BPTB regarding kneeling pain and anterior knee pain. Other outcomes seem to be affected by the number of strands of the HT autograft, the fixation technique, and the type of study design, indicating superiority of the four-strand HT autograft with the use of an extra-cortical button fixation. Overall, there is no clear superiority of BPTB over HT autografts for ACL reconstruction, as both types present similar outcomes in the majority of postoperative parameters. Autograft selection should be individualized according to each patient's needs and more RCTs are warranted in order to reach safer results on the appropriate autograft type.