Pretoria – Nobody was paying attention to Pablo's horn, worth thousands of dollars, or the ticks scuttling in the folds of skin between his hind legs.Instead, veterinary surgeon Johan Marais and a team of doctors were focusing on his swollen left front leg. The young white rhino bull was lying on his back, the leg held up by a winch, on a table at Onderstepoort Veterinary Academic Hospital. Marais was about to perform what he believed was the first ever arthroscopic operation (keyhole surgery on a joint) on a rhino. "I don’t think it's ever been done on a rhino in the world," he said on Monday.Marais is CEO of Saving the Survivors, a non-profit organisation that treats between 80 to 120 rhino a year for gunshot wounds, bone fractures resulting from gunshot wounds, or hack wounds. Several months ago, three-year-old Pablo was shot in a failed poaching attempt at a private game reserve. The bullet went through the wrist joint.At the time, he was treated in the bush, and appeared to be fine. Recently, however, the limb had become swollen and he was in pain and limping. Marais suspected there were bone fragments in the joint and that the young rhino had developed osteoarthritis, a condition caused by loss of cartilage and the growth of bony spurs called osteophytes.He feared that Pablo's problem would get worse as he got older, and heavier.(Lerato Sejake, News24)On Monday morning, he was darted and driven to Onderstepoort in the back of an enclosed trailer. Several staff at the equine clinic gathered to watch as the tailgate was opened.Pablo's eyes were covered in an orange towel. He had been given a sedative, but was still on his feet. Getting him out looked like wrestling a very large, very drunk, and very grumpy person out of a bar. A cattle prod was used to get him to move. Each time it was used, the rhino reacted with a jolt and attending vet Gerhardus Scheepers and several men were able to push him towards the ramp, backwards, a few more centimetres.Once on the ramp, his left front leg slipped off. He was pushed back on. It took about 10 people to pull and push the 600kg pachyderm the few metres to the entrance of the operating theatre, where his legs were attached to a winch.He was then hoisted, upside down, through a set of large doors, onto the operating table, where he was anaesthetised. Because of his thick skin, it was difficult to see the structures that lie below, making it difficult to know where to cut. Marais got around the problem by inserting four needles into the skin at the joint. They showed up on the radiograph, enabling him to see better where to make the incisions needed to insert his instruments.Very little was known about rhino anatomy, Marais explained before the operation. He was transferring his experience with horses to rhinos.Although a rhino's gastro-intestinal system is very similar to a horse's they are not entirely built like horses. Bits of them are similar to cows, but other parts are completely unique.Similarly, the effects of painkillers and antibiotics on them had not been properly studied, and once again the knowledge gained from treating horses and cattle was being relied on.Marais had done some research on his own, but it was still mostly a matter of trial and error and thumb-sucking.(Lerato Sejake, News24)Once he had scrubbed in and studied the X-ray of the joint, Marais and the team got to work. He inserted a camera into one cut and an instrument into another. A steady stream of pale red liquid poured out of the cuts, from the liquid that was being pumped into the joint to wash it out. On the screen he could see the surfaces of the joints. The area where there was still cartilage looked like a hill covered in fresh snow. Other areas looked like a lunar landscape, which was where bone was grinding against bone. The bullet had destroyed the fluid-filled capsule that surrounded the joint. As a result Pablo had, as suspected, developed osteoarthritis.Parts of the bone at the joint had turned to "ice cream", as Marais described it. It had become soft and grey, instead of hard and yellow like healthy bone. Bony spurs had formed that were making walking painful.Marais used a rongeur, an instrument with a sharp, round tip, to gouge away the soft bone. After pulling out about a dozen small pieces, the size of human teeth, he realised he was not making much progress. He asked for a shaver with a bur-tip, a rotary cutting instrument. It looked like a smaller, leaner version of a hand blender. "This is quite aggressive. We don't normally do this, but this isn't normal," he said, explaining that the amount of damage was worse than he had expected. He used the shaver to grind away the soft bone until he got to hard, healthy bone. Just over an hour later, and he was done. He stitched up the cuts and gave Pablo a shot of painkiller and antibiotic. "I think he’s going to be in pain for a while, but ultimately he'll be okay. He won't not limp, but he'll have a slight limp," Marais said. Pablo was hoisted back out of the theatre, onto a large stretcher and wheeled back into his trailer to be taken back to his home."We never had to do this in previous years," Marais said of rhino operations. But because of their value, such operations now were becoming almost routine.