Outcomes of ACL Reconstruction with Anterior Tibialis Allograft
Allografts avoid donor site morbidity of ACL reconstruction. Anterior tibialis tendon provides adequate graft size and strength. However, tendon-to-bone healing is slower than bone-to-bone healing. This may impact outcomes, particularly with accelerated rehabilitation protocols.
Retrospective Case Series
A retrospective case series of 125 ACL reconstructions using anterior tibialis allograft reported a 38% reoperation rate at 55 month follow-up.1 16 patients (23%) required revision ACL reconstruction at a mean of 22 months. Failures occurred more frequently in younger patients and with accelerated rehabilitation.
Prospective Randomized Trials
A randomized trial compared outcomes of ACL reconstruction using anterior tibialis allograft versus BPTB autograft in 80 patients.2 No differences occurred in stability, range of motion, or functional scores at 2 years. Another trial of 58 patients found similar results at minimum 5 years follow-up using Achilles tendon allograft versus BPTB autograft.3
Cadaveric Biomechanical Studies
Biomechanical studies reveal significantly weaker time-zero pullout strength for soft tissue graft fixation versus BPTB grafts.4 Cyclic loading further deteriorates fixation. This suggests potential issues with accelerated rehabilitation protocols before tendon-bone healing occurs.
Concerns exist over applicability of accelerated rehabilitation protocols designed for autografts to soft tissue allografts. Slower progression may better match graft incorporation. One study delayed return to sports until 11-12 months with low failure rates.5 Close monitoring for graft elongation or laxity is prudent.
With appropriate fixation andgradual rehabilitation, anterior tibialis allograft provides reasonable outcomes for ACL reconstruction. However, failure risk may be higher than autografts, particularly in younger patients. Surgeons should counsel patients accordingly.
1. Singhal MC, Gardiner JR, Johnson DL. Failure of primary anterior cruciate ligament surgery using anterior tibialis allograft. Arthroscopy. 2007;23(5):469-475.
2. Sun L, Zhang J, Ge L, et al. Anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft: comparison of autograft, fresh-frozen allograft, and γ-irradiated allograft. Arthroscopy. 2013;29(2):211-217.
3. Poehling GG, Curl WW, Lee CA, et al. Analysis of outcomes of anterior cruciate ligament repair with 5-year follow-up: allograft versus autograft. Arthroscopy. 2005;21(7):774-785.
4. Grover DM, Howell SM, Hull ML. Early tension loss in an anterior cruciate ligament graft. A cadaver study of four tibial fixation devices. J Bone Joint Surg Am. 2005;87(2):381-390.
5. Shino K, Inoue M, Horibe S, Hamada M, Ono K. Reconstruction of the anterior cruciate ligament using allogeneic tendon. Long-term followup. Am J Sports Med. 1990;18(5):457-465.