Tendon Allografts
Lennard Funk
What is an Allograft?
An allograft is bone or soft tissue that is transplanted from one person to another.
Why use an Allograft?
Allografts, or donor tissues, are frequently preferred over autografts, a person's own tissue, for a variety of reasons. Allografts can help patients regain mobility, restore function, enjoy a better quality of life, and even save a life in the case of cardiovascular tissue or skin.
Allografts retain important biologic and biomechanical characteristics, which facilitate faster and greater healing.
Generally, since no second surgical site is required (as there is when an autograft is utilised), healing time may be shorter and less painful. In addition, autografts are only available in limited amounts, from limited areas of the body. Allografts are more readily available.
We commonly use tendon allografts for chronic muscle tendon ruptures of the pectoralis major muscle and biceps muscle at the elbow. Allograft is only used if a direct repair is not possible.
What to expect after surgery
Following the surgery, your body should begin the natural process of tendon healing. The allograft tissue acts to provide a scaffolding or support system which permits ingrowth of tendon cells and promotes the formation of new tendon. Eventually, the allograft tissue is replaced by your own new tendon tissue. This is the end goal of transplantation.
Is it safe?
To ensure that the donated tissue poses the lowest possible health risk, a blood sample from the donor is tested for the following:
- Blood tests for HIV, Hepatitis, and Syphilis
- Procedures to ensure the absence of bacteria and fungi
All testing is performed in government-certified (or equivalent) laboratories to very strict standards and regulations.
The allograft tissue is processed to remove all cellular content and remove any risk of infection transmission and tissue rejection. This makes the risk of disease transmission extremely remote.
Musculoskeletal (bone and tendon) tissue is prepared in special controlled (cleanroom) processing suites. Chemical (virucidal and bactericidal) agents penetrate allograft tissue and help to significantly reduce the potential transmission of disease.
The graft is sterilised and the tissue is carefully cryopreserved (frozen at a controlled rate) in an effort to preserve the original structural and biological integrity of the graft.
Quality assurance checks are then done, including aerobic and anaerobic cultures and any applicable additional testing. Finally, all donor records are reviewed to determine eligibility for transplantation.
Factoring Relative Risk
The risk of hepatitis B after blood transfusion is 1/63,000. The risk of hepatitis C is 1/100,000, and the risk of HIV is 1/1,000,000. The risk of HIV after bone transplantation is 1/1,500,000. The risk of HIV after soft tissue transplantation is 1/1,600,000 with secondary sterilization.
To put this in the proper perspective, one should remember that the risk of death due to pregnancy is 1/10,000, the risk of death from administration of penicillin is 1/30,000, and the risk of death with oral contraceptives is 1/50,000. In fact, it may be more dangerous driving to the hospital than receiving a bone graft at the hospital.
