Rafael Nadal's Wounded Knees Make Wimbledon Decision Fraught With Risk

Does the reward outweigh the risk? That is what Rafael Nadal will ponder before he makes a final decision as to whether his knees can stand up to a vigorous defence of his Wimbledon title.

After tests revealed that he is suffering from tendinitis in both his knees, the world No1 promised last week to give 200% to be 100% fit for Wimbledon, but also said he would not risk playing if he is not 100%.

It is not in Nadal's nature to do anything half-heartedly, so if he does play he will go full throttle in an effort to repeat his heroics of 12 months ago, when he beat Roger Federer in a final described by many as the best ever. He practiced at Wimbledon on Tuesday and will test himself in an exhibition at the Hurlingham Club tomorrow , but the problem for Nadal is that at 23, if his knees have not had enough rest since his early French Open exit last month, he could be risking further damage.

"The question is whether you're just patching it up or whether you want a full resolution," Simon Jennings, a consultant orthopaedic surgeon at London's Harley Street, said. "I would expect him to really try to get to Wimbledon. If he manages to get through it without any pain or inflammation then all well and good, but he may be making it worse for a while afterwards.

"I'd suspect this is something he's been managing. The best treatment is going to be rest. If he wants to compete, he's going to have to keep himself in tune, with lots of physiotherapy and anti-inflammatories to reduce the pain."

For Nadal this is nothing new. He missed the Davis Cup final in December because of tendinitis and the decision paid off when he won the Australian Open title at the start of this year. He limped to defeat against Andy Murray in a tournament in Rotterdam in February, after which he said: "I could not push up on my serve and it was killing [my mind]."

During the clay-court season and again in practice on grass on Tuesday, Nadal has experimented by removing the tape on his knees that has become a common sight in recent years. His coach and uncle, Toni Nadal, admitted that they had known that the injuries could flare up at any time, but said they had hoped he would last until the end of Wimbledon.

John Hardy, a consultant specialist in orthopaedic and trauma surgery in London and Bristol, said he was "amazed he has been able to go on" as the pain has built up. "When you go up and down stairs, [the stress on] your patella is three times your body weight," he said. "When you get up from a chair, it is seven times your body weight. When you are running around the tennis court, sometimes with your knees at angles, the stress on your patella and your quadriceps is enormous."

Jennings and Hardy said it was impossible to be entirely sure as to the exact nature of Nadal's injuries without examining him but both said they thought it was most likely to be "quadriceps tendinitis", affecting the tendon linking the knee to the quadriceps muscles. The usual remedy is rest, while ice, anti-inflammatories and strengthening exercises are also advised.

As someone who relies on his legs more than the likes of Roger Federer, Nadal is perhaps more susceptible to knee injuries than others, but as a phenomenal athlete, he is also able to bounce back faster. "A professional athlete is going to recover quicker than a weekend athlete, your office worker," Jennings said. "You would probably want two to four weeks, but as an ATP Tour player that is not easy."

Todd Martin, the former world No4 and twice a semi-finalist at Wimbledon, suffered from chronic tendinitis during his career. The American said the pain was playable but if the effect on the knee was significant, it would "undoubtedly be pretty limiting physically and mentally".

"[For] Nadal, having to deal with a knee injury is especially difficult though," he said. "The sport continues to get more athletic and Rafael leads the pack in that category. His movement and strength are astounding and they have always had a carry-on effect into his mental and emotional strength."