Purpose
The purpose of this study is to investigate the role of augmentation of anatomic anterior cruciate ligament (ACL) reconstruction with a lateral extra-articular tenodesis (LET) in individuals who are deemed as being at high risk of graft failure. Functional results are reported at 6 and 12 months.
Methods
The ‘Stability Study’ is an ISAKOS sponsored multicenter, randomized clinical trial, for which 600 active patients under the age of 25 years undergoing ACL reconstruction surgery are randomly allocated to either ACL reconstruction alone (control) or ACL reconstruction with LET. In this separate sub study, three of the study centers collected early functional assessment data on the recruited patients. Our primary outcome was Limb Symmetry Index (LSI) calculated using a series of four hop tests at six and twelve months postoperative. Secondary outcomes measures included quadriceps index (QI) and hamstrings index (HTI) measured using an isokinetic dynamometer, Lower Extremity Functional Scale (LEFS) and the Four-Item Pain Intensity Measure (P4). The results are reported using means and standard errors.
Results
To date, 188 patients completed the hop test at six months and 158 patients have completed the hop test at 12 months postoperatively. At six months, the ACLR alone group had a mean LSI of 97.5% ± 0.6 and the ACLR plus LET group had a mean LSI of 95.5% ± 0.6 (p=0.03). At 12 months, the ACLR alone group had a mean LSI of 97.8% ± 0.6 and the ACLR plus LET group had a mean LSI of 97.9% ± 0.5 (p=0.95). Isokinetic strength testing was completed by 121 and 78 patients at six and 12 months respectively. At six months, the ACLR alone group had a mean peak torque QI of 82.5% ± 1.9 and a mean average power QI of 83.4% ± 1.8. The ACLR plus LET group had a mean peak torque QI of 76.1% ± 1.8 (p=0.02) and a mean average power QI of 76.9% ± 1.6 (p=0.01). At 12 months, the ACLR alone group had a mean peak torque QI of 92.5% ± 2.1 and an average power QI of 92.5% ± 1.8 and the ACLR plus LET group had a mean peak torque QI of 87.3% ± 2.0 (p=0.08) and a mean average power QI of 97.0% ± 1.8 (p=0.04). At six months, the ACLR alone group had a mean LEFS score of 70.4 ± 0.6 and the ACLR plus LET group had a mean LEFS score of 68.3 ± 0.6 (p=0.01). At 12 months, the ACLR alone group had a mean LEFS score of 72.9 ± 1.0 and the ACLR plus LET group had a mean LEFS score of 74.1 ± 1.0 (p=0.37). Furthermore, we found no significant differences between the two groups in hamstring indices or subjective pain.
Conclusions
Significant differences were found at six months between the two groups for hop test LSI, peak torque and average power QI, and subjective functional score. Only average power QI remained significant at 12 months. More definitive conclusions will follow the completion of this study.