Hybrid versus double bundle hamstring ACL reconstruction – a review of 626 cases

OBJECTIVES: Since 2008, we have offered patients Hybrid ACL (hamstring plus LARS ligament) graft or double bundle hamstring graft. We allow the patients with Hybrid ACL to jog at 2 months and return to sports at 6 months. In comparison we allow the double bundle hamstring group to jog at 4 months and return to sports at 12 months. We considered the hybrid graft, due to its initial stiffness, would allow safe accelerated rehabilitation. Our primary aim was to establish whether Hybrid ACL graft has a higher failure rate compared to double bundle hamstring graft. Our secondary aim was to compare reoperation rates and clinic visit rates between the two groups. METHODS: We performed a retrospective study of skeletally mature patients that underwent primary isolated ACL reconstruction by the senior author between 2008 and 2015 comparing double bundle hybrid ACL (DB Hyb), single bundle hybrid ACL (SB Hyb), and double bundle hamstring ACL (DB Ham) graft types. Charts were reviewed to assess reoperation rate, complication rate, re-rupture rate, and number of clinic visits. Graft tensioning positions, remnant sparing percentage, and concurrent meniscal procedures were reviewed as well. RESULTS: 626 patients met the inclusion criteria. DB Hyb group had more males (77%) and a longer mean follow up (5.6 years) than the other two groups. Rerupture rates were 1.2% per year for DB hyb, 0.5% per year for SB Hyb, and 0.8% per year for DB Ham group. DB Hyb group trended towards a higher reoperation rate for arthrofibrosis compared to DB Ham (9.4% vs 4.7%, p-value 0.054). There was no difference in number of clinic visits between the 3 groups. CONCLUSION: Double bundle hybrid ACL group was associated with higher rates of arthrofibrosis surgery but equivalent rates of failure.