I always observe how patients with knee pain walk into my consultation room. From that, I can tell which leg is hurting, and how bad it is hurting .
After all, knee pain is one of the most common symptoms that I see in my practice.
Mr X hobbled into my clinic one day, complaining of pain in both knees. He could not play golf, and even walking around a shopping centre with his wife was painful.
He had tried medication (painkillers, supplements, traditional Chinese medicine), medicated plasters, gels, walking aids, physiotherapy, lubricant injections and even had special shoes designed to shift the stress away from the knees.
He had read up extensively about the surgical options available and he wanted my opinion.
After looking at his X-ray scans, which showed severe osteoarthritis, and considering his age of 69, I recommended the most reliable operation for someone in his situation: A total knee replacement.
He then asked a question that I had heard many times before.
Was there any way to preserve his knee and avoid replacing it with metal and plastic?
My answer was no, not in his case - his arthritis was too advanced.
But I have wondered if I could have preserved his knees had he come to see me years earlier.
VITAL PARTS OF THE KNEE
Knee preservation surgery is a broad concept that uses minimally invasive keyhole techniques (arthroscopy) to preserve the vital components of the knee.
Knee arthritis occurs when there is cartilage damage, which causes pain and stiffness. Vital components of the knee that contribute to its longevity are the meniscus, cartilage and ligaments.
The meniscus is a crescent-shaped structure made of cartilage. It absorbs shock and stabilises the knee. Forty years ago, surgeons routinely removed the entire meniscus when it was torn.
We now know that removing the whole meniscus is a bad idea. Without it, the knee will almost always develop arthritis .
There is now a big push to repair a meniscal tear and even if you cannot repair it, only the torn potion should be removed.
The cartilage is the white shiny layer covering the ends of the bones. It has lubricating and shock-absorbing qualities. Once you damage it, however, it has limited potential of healing itself.
But we know that cartilage damage in the knee should be treated early. By the time the damage is widespread, there is little doctors can do to regenerate the cartilage.
The patient may have no choice but to undergo a knee replacement with metal and plastic components.
Mr Y, 49, a university lecturer, was fortunate. He sought help early and managed to preserve his knees.
An avid basketball player, he started to experience pain in both knees after a game. It worsened to a point where he could not stand in front of his class for more than 15 minutes.
Magnetic resonance imaging scans showed cartilage damage, as well as "loose bodies" in his knees - little pieces of bone and cartilage that form during the degeneration process. These free-floating objects occasionally jam up the knee, causing a sudden locking sensation.
It is like having a pebble in your shoe when you are walking.
The loose bodies accelerate cartilage damage, grinding away the cartilage when the knee moves.
The advantage of keyhole surgery is that even if both knees are operated on at the same time, the patient can often walk out of the hospital the next day.
Mr Y eventually underwent keyhole cartilage regeneration and removal of loose bodies in both knees. He is now able to stand and teach for an hour.
More importantly, he started playing "old man basketball". He described it as more passing, less running and jumping, and playing with people his own age.
If he continues to take care of his knees and modify his activities to avoid further wear and tear, he might not require a knee replacement at all.
•Dr Tan Chyn Hong is an orthopaedic surgeon specialising in the shoulder, knee and elbow at The Orthopaedic Centre (Novena) at Mount Elizabeth Novena Specialist Centre.