Three surgeons (D. Sonnabend and A. Young, orthopaedic surgeons, and C.Rolfe Howlett, veterinary surgeon, at the Royal North Shore Hospital, Sydney) surgically cut the tendons and damaged the rotator cuff in healthy baboons in an attempt to replicate the healing process in humans.
Eight female baboons, all over 15 years of age, had been used in experiments and breeding programs all their lives and scheduled for death, were taken from Australian Baboon Breeding Colony to be used in these highly invasive experiments.
The researchers cut the tendons and then undertook tendon-to bone repair of the rotator cuff of each animal to study the progression and rate of healing in an attempt to extrapolate the results to humans who suffer tendon damage.
A rotator cuff is the anatomical name given to the group of tendons and muscles in the head of the shoulder where it connects to the shoulder blade. (It is a part of the shoulder that allows for the up, down, back, and forward or rotating movements of the shoulder).
The left shoulder was prepared by shaving from the base of the neck to the elbow and nipple line. The baboon was then placed on her side and curetted to bleeding spongy bone within the shoulder. The cuts were then repaired and the wound was closed.
Formal post-operative immobilisation was not used since immobilisation of the baboon shoulder in a sling or splint was not feasible and plaster casts would have been extremely difficult to apply and maintain.
To study the resultant healing, the baboons were killed in pairs, two at 4 weeks post operation; two at 8 weeks post operation; two at 12 weeks post operation; and two were killed at 15 weeks post operation.
Animal Welfare Concerns
The female baboons would normally reside in family groups but for this experiment they were housed in separate cages to avoid fighting and minimise movement of the shoulder.
Although the baboons were held in separate cages, two baboons fought through their cages and according to the researchers ‘this may have impacted on the results’.
Relevance to Humans
Formal post-operative immobilisation was not used on these animals however, after operations in humans immobilisation would be a standard procedure. Therefore immediately, the results of the study are flawed – not giving a true result of the healing process in humans.
The researchers in fact acknowledge the problems that could arise in extrapolating results to humans because the primates were healthy and their bones and tendons were normal whereas this is not the case with human patients. They also state that “consistent underlying histopathological features associated with the failure of the cuff in man is that of degeneration within the tendon” and go on to say “We therefore suggest that this animal model represented only a best-case scenario for repair” adding that “Our study is purely observational and has limitations”.
The final conclusion was a recommendation “that excessive tension on the repair site should be avoided for at least 12 weeks” – not a surprising recommendation!
Cost – Benefit Assessment
The publication by the researchers states that “these results support the use of a post-operative rehabilitation programme in man”. This is already well known and documented by orthopaedic surgeons around the world.
Putting non-consenting, highly sentient, beings through the pain and suffering of serious surgery (and death), to merely demonstrate what is already known in the field of orthopaedic surgery and rehabilitation cannot be justified.
The Australian and New Zealand Council for the Care of Animals in Research and Teaching states that: “Using animals for scientific purposes is acceptable only when any harm done to the animals is very greatly outweighed by the benefits of their use”. The study is not only highly unethical; it is unscientific. Data cannot be extrapolated from one species to another with certainty of success.
This research was approved by the University of New South Wales Ethics Committee and the Central Sydney Area Health Service Animal Welfare Committee.
Humane Research Australia has emailed the committee seeking the minutes of the meeting that approved this experiment on aged baboons.
What you can do
University of New South Wales Animal Ethics Committee
Office of the Deputy Vice-Chancellor (Research)
University of New South Wales
NHRMC, GPO Box 142
Canberra ACT 2601
Australian Research Council
GPO Box 2702
asking that they no longer fund unscientific animal-based experiments.
- Sonnabend, DH; Howlett, C.R; and Young, AA (2010) Histological evcaluation of repair of the rotator cuff in a primate model, J Bone and Joint Surgery 92-B:586-94.