Surgeon operates to rescue chimp with rare deformity

May 19, 2008

An orthopaedic surgeon at the University of Liverpool has performed a groundbreaking operation on a chimp in Cameroon to correct a deformity more commonly seen in dogs.

The three year-old chimp called Janet was rescued from the Cameroon pet trade last year and now lives in a chimpanzee reserve supported by the Cameroon Wildlife Aid Fund. Janet was unable to climb and had difficulty walking because a bone in her forearm - the ulna - had stopped growing.

It is thought that her condition, known as angular limb deformity, is a congenital problem, but could also have been caused or aggravated by being chained at the wrist by traders. This forced the arm’s radius to grow in a circular manner making her arm severely bent. Vets have seen the deformity in dogs before but never in chimpanzees and were called in to assess Janet’s condition.

Rob Pettitt, orthopaedic surgeon at the University’s Small Animal Teaching Hospital, said: “Surgery to correct the condition in dogs is less complex than the procedure in chimps. In dogs bone tissue stops growing early in life, so once the limb is straightened there is little time for the deformity to recur and interfere with bone development. In chimps and humans however, the areas of growth at the end of long bones can stay open for years, so there is plenty of time for the condition to return. We therefore sought the advice of specialists at Robert Jones and Agnes Hunt orthopaedic hospital at Oswestry - to make sure we protected any growth left in Janet’s limb.

“The first step was to remove the far end of the ulna, which had become compacted due to the continued growth of the radius. A 14mm triangular section of bone was then removed from the radius in order to straighten the limb and a bone plate was inserted into the radius to secure the two ends of the bone.”

Selling chimps as pets is illegal but rife on the black market in Cameroon. Adult chimpanzees are slaughtered for their meat and the young chimps are then taken away and sold as pets.

Rachel Hogan, manager of the chimpanzee reserve in Cameroon, said: “Janet is recovering well and has now rejoined her group at the reserve. She has been undergoing physiotherapy so that she can learn how to use the limb properly. She is made to grip a ball a few times a day and undo bottle tops to exercise her wrist. The X-rays show the surgery was a complete success.”

Source: University of Liverpool