Dr Prodromos ACL Blog February 2016

Dr Prodromos ACL Blog February 2016

Anterior cruciate ligament reconstruction with a novel porcine xenograft: the initial Italian experience Anterior cruciate ligament reconstruction and service in the British Army Long-Term Examination of Bone Mineral Density in the Calcanei After Anterior Cruciate Ligament Reconstruction in Adolescents and Matched Adult Controls

  1. Anterior cruciate ligament reconstruction with a novel porcine xenograft: the initial Italian experience
  2. Anterior cruciate ligament reconstruction and service in the British Army
  3. Long-Term Examination of Bone Mineral Density in the Calcanei After Anterior Cruciate Ligament Reconstruction in Adolescents and Matched Adult Controls

Anterior cruciate ligament reconstruction with a novel porcine xenograft: the initial Italian experience

Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, Roberti Di Sarsina T, Raggi F, Benzi A, Marcacci M. Joints. 2015 Nov 3;3(2):85-90.

At the current state of the art in anterior cruciate ligament (ACL) reconstruction, multiple techniques have been presented but none has given clearly defined and improved results. One of the main issues concerns the choice of graft. The concept of using xenograft tissue, defined as a graft tissue from one species and destined for implantation in an unlike species, was introduced in order to try to overcome the mechanical and biological concerns associated with synthetic materials and the safety and quality concerns and availability problems of allograft tissue. Xenograft tissue carries the risk of producing an immunological reaction. In order to try to overcome or attenuate the immune response against porcine xenograft tissue, the Z-Process® (Aperion Biologics Inc, San Antonio, Texas, USA) has been developed and used to produce the Z-Lig® family of devices for ACL reconstruction procedures. Z-Lig® is a tendon graft with or without bone blocks, sourced from animal tissue in a manner consistent with what has normally been sourced from human tissue, and processed to overcome anti-Gal-mediated rejection and to attenuate other immunological recognition in humans. All this while ensuring sterility, viral inactivation and preservation of mechanical proprieties appropriate for an ACL reconstruction device. The Z-Lig® device has been tested in skeletally mature monkeys and given interesting and promising results from the preclinical performance and safety profile point of view. On this basis, it was possible to proceed with the first clinical trial involving humans, which gave similar encouraging results. The Z-Lig® device has also been implanted in Italy at the Rizzoli Orthopaedic Institute in Bologna, as a part of international multicenter prospective randomized blinded controlled study aimed at comparing xenograft with allograft tissue.

This is an interesting paper, one of the first reports of realistic xenograft (use of tissue from another species) use: in this case a porcine graft. The paper notes that “encouraging” short term results in monkeys and humans have been seen for this pig tissue graft. Porcine heart valves were one of the earliest successful xenografts used, and other porcine tissue has been successfully used in other applications. The potential graft material for ACL reconstruction is autograft (host tissue), allograft (human cadaver tissue), Xenograft (tissue from another species) and synthetic. Of these, there have been fewer xenograft reports than any other type. The relevant parameters are always, safety, efficacy and cost, in that order. Allograft have received relatively wide usage but with clearly inferior efficacy. Synthetics have less use and also greatly inferior efficacy. It will be interesting to see if this Xenograft proves safe and effective once adequate followup has been obtained. If so they may prove a useful tool in the surgeon’s armamentarium if costs are modest. However caution is advised since even the worst performing tissue are often reported as successful at short term follow up. Thus, it will be several years at least until we know if this porcine Xenograft is useful. Until then autograft remains the clear gold standard for ACL reconstruction

Anterior cruciate ligament reconstruction and service in the British Army

Halford JV, Lam KB, Folkes SE, Sadhra S. Occup Med (Lond). 2015 Nov 12. Epub ahead of print

BACKGROUND: In 2005, British Army recruiting policy was revised to permit applicants with a history of anterior cruciate ligament reconstruction (ACLR) to be accepted for an initial period of engagement.
AIMS: To determine whether personnel with an ACLR history are more likely to be medically discharged due to further injuries and complications than those without.

METHODS: A retrospective study of personnel commissioned or enlisted into the British Army between January 2006 and July 2009. ACLR cases were identified from personnel and medical records and were age and sex matched to randomly selected controls. Reasons for discharge were identified.

RESULTS: A total of 69 cases and 140 controls were included. A significant increase in risk of medical discharge was found in those with ACLR (incidence risk ratio was 3.04; 95% confidence interval 1.24-7.45). Sixty-one per cent of cases experienced complications linked to their previous surgery.

CONCLUSIONS: The current British Army policy on recruitment of those with a history of ACLR should be reviewed in terms of fitness for service and risk of foreseeable harm in these individuals.

© The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. PMID: 26563289 [PubMed - as supplied by publisher]

This paper present the surprising conclusion that over 60% of the British military recruits who had had ACL reconstruction experienced complications related to their having had prior ACL surgery. There was also a significantly increased risk of medical discharge. The authors point out that prior to 2005 ACLR was a cause for rejection for military service but that after 2005 successfully reconstructed recruits were accepted. Given the high rates of return to sports after ACLR this high rate of difficulty after ACLR in this population is surprising and troubling. It also highlights the importance of ACLR being performed by specialists who are skilled and experienced in ACLR surgery. I know of no comparable study from the United States military.

Long-Term Examination of Bone Mineral Density in the Calcanei After Anterior Cruciate Ligament Reconstruction in Adolescents and Matched Adult Controls

Månsson O, Sernert N, Ejerhed L, Kartus J. Arthroscopy, 2015, epub ahead of print.

PURPOSE: The aims were to evaluate the results 10 to 20 years after anterior cruciate ligament (ACL) reconstruction performed in adolescents in terms of bone mineral density (BMD) in the calcanei using the dual-energy x-ray absorptiometry (DXA) technique, activity level, and quality of life.

METHODS: A case-control study of adolescents who underwent ACL reconstruction between 1992 and 2002 was performed. The inclusion criterion was a unilateral ACL injury. The exclusion criteria were bilateral ACL injury, contralateral ACL reconstruction, posterior cruciate ligament injury, and previous or present fractures of either lower extremity. The BMD was measured in both calcanei using the DXA technique and compared with a control group of adult ACL-reconstructed patients and with a DXA reference database. The age of the control group was similar to that of the patient group at the time of BMD assessment, performed 60 months after reconstruction. Activity was measured with the Tegner activity scale. The EQ-5D was used to evaluate quality of life.

RESULTS: Thirty-two adolescents (11 boys and 21 girls), aged 12 to 16 years, with a symptomatic unilateral ACL rupture, underwent reconstruction at near skeletally mature age. Of these patients, 29 (91%) took part in the follow-up examination. The BMD values for the male patients were lower on the injured and non-injured sides (-15.2% [P = .02] and -11.8% [P = .05], respectively) compared with the control group. The values for the female patients were -0.8% (P = .84) and -2.2% (P = .69), respectively. Correspondingly, the BMD values for the male patients were lower on the injured and non-injured sides (-8.2% and -4.9%, respectively) compared with the male reference database. The BMD values for the female patients were higher on the injured and non-injured sides (4.1% and 4.3%, respectively) compared with the female reference database. In the control group, female patients had a significantly lower value for the Tegner activity scale preoperatively (median, 2.0; range, 0 to 5) than the female patients in the study group (median, 3.0; range, 2 to 8) (P = .006). In the study group, the Tegner activity scale at follow-up showed a significant correlation with the BMD on the injured side for male patients (ρ = 0.67, P = .03) but not on the non-injured side (ρ = 0.50, P = .14). In the control group, the Tegner activity scale at follow-up showed a significant correlation with the BMD on the non-injured side for female patients (ρ = 0.61, P = .03) but not on the injured side (ρ = 0.34, P = .25). The Tegner activity scale and EQ-5D showed no significant differences between the study groups.

CONCLUSIONS: In the long-term, the BMD in the calcanei of patients who were adolescents at the time of ACL reconstruction differed from that of a control group and a reference database. This study indicates that boys with an ACL injury and subsequent ACL reconstruction run a subsequent risk of a significantly lower BMD in their calcanei as adults and, consequently, an increased future fracture risk.

Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier inc. All rights reserved. PMID: 26545306 [PubMed - as supplied by publisher]

This is a very interesting paper that follows up an earlier paper from this same group showing lower heel bone mass after ACL tear. The lower bone mass acutely can easily be explained by the period of decreased weight bearing that occurs after ACL tear and reconstruction. It is, however, quite surprising that this lower bone mass should be persisting many years later into adulthood. This indicates that Vitamin D and Calcium supplementation should be part of the routine post operative treatment of ACLR, which is not currently generally the case. It would also indicate that bone mass monitoring should probably be instituted for many. If bone mass deficiency still existed it might be that anabolic bone treatment might be indicated for this generally active population.

  • American Academy of Regenerative Medicine
  • American Board of Regenerative Medicine
  • aossm
  • isakos
  • Rush University Medical Center
  • aana
  • aaos
  • esska
  • cartilage