Effect of Calcium Phosphate-Hybridized Tendon Graft in Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial
Mutsuzaki H, Kanamori A, Ikeda K, Hioki S, Kinugasa T, & Sakane M. American Journal of Sports Medicine. 2012; 40:1772-1780. doi 10.1177/0363546512449618
Anterior cruciate ligament (ACL) reconstruction is performed regularly in the orthopedic world with relatively favorable results. While the selection of a hamstring autograft allows for fewer issues at the harvest site than the patellar tendon autograft, the problem that arises is the lack of bone block to assure graft fixation and possible widening of bone tunnels over time. The purpose of this randomized controlled trial was to assess the effectiveness of calcium phosphate (CaP) graft hybridization to improve graft fixation in comparison to a conventional single-bundle ACL reconstruction. Sixty-four patients randomly received hamstring allograft ACL reconstruction with either CaP (n = 32) or a conventional graft (n = 32). Meniscal injury was collected and treated accordingly, there were no differences between groups. Surgical methods and rehabilitation were identical for the two groups. Patients were evaluated at 3 time points (preoperatively, 1 year and 2 years post operatively). Evaluation included a pivot-shift test (under anesthesia), KT-1000 test, CT for tunnel diameter, MRI, patient outcomes (i.e., Tegner activity, Lysholm, IKDC), and arthroscopic examination of revascularization at the 1 year follow up (n = 54). The CaP group had significantly less anterior translation with a KT-1000 than the convention group at the 1- and 2- year follow-up appointments, better Lysholm scores at the 2-year follow up, and less tunnel enlargement (indicating better fixation) at the 1-year follow-up. Other patient outcomes (i.e., Tenger, IKDC), revascularization, and pivot shift results were not different between the two groups.
Clinically, it appears that this novel approach may have some benefits within the orthopedic population. The hamstring autograft often has less graft site complications than the patellar tendon, but can result in more tunnel enlargement and a looser graft that may be more likely to fail. CaP involves soaking the hamstring autograft in a solution to help encourage better fixation to combat the lack of a bony block for fixation. While there were some favorable outcomes, it would be very interesting to follow the results of this study for a longer period of time. It is still a relatively novel approach that should be further evaluated, including looking at the incidence of osteoarthritis development. Once an ACL tear occurs, the priority becomes minimizing long-term issues such as instability and osteoarthritis development. It may be critical to find an intervention to help improve longer-term ACL reconstruction outcomes during the time of surgery. It is interesting that meniscal status did not affect outcomes in either group, as the meniscus is often times a contributing factor to disability and degeneration. Once a knee injury occurs, the pathway to osteoarthritis is accelerated. Some physicians are starting to realize this, and start to investigate anecdotal and novel techniques to be utilized at the time of injury or surgery, prior to any structural changes occurring. Has anyone had an athlete who may have undergone the CaP hybridization? Has anyone heard of any physicians trying techniques?
Written by: Nicole Cattano
Reviewed by: Stephen Thomas