Five-Strand Hamstring Autograft Anterior Cruciate Ligament Reconstruction.

Abstract

Hamstring tendon autograft remains a popular graft choice for anterior cruciate ligament (ACL) reconstruction because of its favorable biomechanical properties, lower donor-site morbidity, and comparable functional outcomes to bone-patellar tendon-bone (BPTB) autograft^1-5. However, variability in hamstring graft size and length remains a challenge, particularly in female or short-statured patients⁷. Smaller graft diameters are consistently associated with increased failure and revision rates, with grafts of <8 mm demonstrating inferior outcomes^6,7,18,19. Magnussen et al.⁶ reported revision rates of 13.6% for grafts of <7 mm compared with 1.7% for grafts of ≥8 mm, and Park et al.¹⁸ and Mariscalco et al.¹⁹ reported no revisions in grafts of ≥8 mm. Although some studies have suggested slightly higher laxity or failure rates with hamstring grafts compared with BPTB in certain populations^3,20-22, large systematic reviews have shown no significant differences in return to sport, rerupture rates, or patient-reported outcomes when grafts are appropriately sized^23,24. The 5-strand hamstring autograft configuration has demonstrated comparable clinical outcomes to the traditional 4-strand construct while more reliably achieving large graft diameters^9,10,12. The present video article outlines the key steps and technical pearls and pitfalls of performing a 5-strand hamstring autograft ACL reconstruction. The semitendinosus and gracilis are harvested after reflecting the sartorial fascia and removing the attached adhesions and bands from each tendon. If a 4-strand configuration is <8 mm in diameter, a 5-strand technique is utilized, tripling the semitendinosus and doubling the gracilis. A diagnostic knee arthroscopy is performed. The tibial tunnel is drilled through an accessory anteromedial portal over the residual ACL tibial footprint. The femoral tunnel is drilled with use of an over-the-top guide and subsequently reamed to a depth of 25 mm via independent femoral drilling at the center of the femoral ACL footprint. Femoral stabilization is then achieved with interference screw fixation, the knee is cycled, and screw-and-sheath tibial fixation is performed. Nonoperative treatment includes formal physical therapy that emphasizes strengthening, stretching, and neuromuscular control¹¹. Surgical alternatives include ACL reconstruction using BPTB or quadriceps tendon autograft or allograft tissue. In cases of insufficient hamstring graft length or diameter, hybrid graft constructs incorporating allograft tissue may be considered¹². Hamstring tendon autograft offers reliable long-term results for ACL reconstruction with a well-established biomechanical profile^1,2, reduced anterior knee pain³, and clinical outcomes comparable to BPTB and quadriceps autograft^4,5,14. Although biomechanical studies have demonstrated similar ultimate load to failure and cyclic elongation between 4- and 5-strand constructs^9,16, the 5-strand technique significantly increased the likelihood of achieving a graft diameter of >8 mm, which has been associated with improved stiffness and lower revision rates^6,17-19. Brzezinski et al. demonstrated larger mean graft diameters with 5-strand constructs (9.32 mm) compared with 4-strand constructs (7.96 mm), without biomechanical compromise¹⁶. Hamstring tendon autograft ACL reconstruction results in outcomes comparable to BPTB and quadriceps autografts, with similar graft failure rates, knee stability, and functional outcomes, and lower rates of anterior knee pain (11.5% versus 17.4%, respectively)^4,5,14. However, increased failure rates have been reported in younger patients and those with generalized ligamentous laxity^13,15. Krishna et al. reported significantly larger graft diameters with 5-strand constructs compared with 4-strand constructs (9.06 ± 0.60 versus 8.13 ± 0.32 mm, respectively; p < 0.05), with no difference in functional outcomes when grafts were adequately sized⁹. Avoid injury to the superficial medial collateral ligament during harvest.Release all fascial bands prior to proximal tendon harvest to avoid premature amputation of the tendon.Harvesting the periosteal footprint may increase graft length by 3 to 4 cm.Remove graft creep with tensioning and knee cycling before fixation.A femoral interference screw should be placed parallel to the tunnel.Preserve 2 mm of posterior femoral wall to avoid posterior wall blowout. ACL = anterior cruciate ligamentACLR = anterior cruciate ligament reconstructionAM = anteromedialBPTB = bone-patellar tendon-boneHT = hamstring tendonMRI = magnetic resonance imagingQT = quadriceps tendonROM = range of motion.