‘Should you consider a Knee Replacement Operation’

Margaret Mullett, the chairperson of the Irish Haemochromatosis Association, has had two knee replacement operations – one in June 2012 and one in September 2013. While it took a bit longer than she expected to recover from the first operation, she is very relieved to be pain-free and can now enjoy 45-minute walks “around the block” near her Dodder home.

Margaret decided to have her knees done because of pain and mobility problems due to arthritis and osteoporosis.

“My left knee troubled me first,” she says.

“I was finding it difficult to go up and down the stairs and, in spite of physiotherapy and a day-case arthroscopy (keyhole surgery to try and repair the damaged joint), it became clear that a total knee replacement was necessary.

“I did the exercises that are recommended before the operation in order to strengthen the knee and then had the operation done three months later in the Santry Clinic under general anaesthetic.

“By September it was my son’s wedding and I was making progress and only using a stick some of the time.

“Soon after that, however, my right knee started to act up so I had that operated on in September 2013. Thankfully, my recovery at that time was much quicker. I had physiotherapy and swam in a heated saltwater pool which is good for recovery.

“Now I have no pain, which is a huge relief. I’m delighted that I’m able to enjoy a walk again and that stairs aren’t a problem now. While I am still wary of falling if the weather is windy or the ground is wet, I am very glad to have had the operations done.

“Many people I know who have had knee operations have been mobile after six weeks, but it depends on how bad the knee is. What I would say to anyone going for the operation is to have patience and follow the advice. It will be worth it. I know that I wouldn’t be walking around pain-free if I hadn’t.”

Surgeon’s view

From a farming background, Consultant Orthopaedic Surgeon, Denis Collins, wanted to be a vet but changed his mind at the last minute.

“I thought being a vet would be a hell of a tough life, so I opted for medicine instead,” he says.

“Orthopaedics* was the only area of medicine that really interested me though. Maybe it’s because I have a practical, mechanical kind of mind. As a doctor, I find that it’s always easy to talk to farming patients about joint replacements because, as a group of people, they know what a bearing is,” he says.

Denis Collins is based at Beaumont Hospital and UPMC Sports Surgery Clinic, Santry and operates to solve three kinds of knee problems.

“The majority of operations would be done because of degenerative arthritis,” he says. “Osteoarthritis, usually in people in their late 50s, is the most common reason for doing a knee replacement operation.

“The next more common reason would be the inflammatory type (of arthritis) like rheumatoid.

“Then there would be operations because of trauma in the past (damage to the knee through sport injury or accident). That injury, for example, loss of the shock absorber in the knee, would eventually manifest itself in arthritis.”

Denis Collins has operated on people as young as 20 and as old as 91.

“In younger patients, it can be the result of post-chemotherapy damage to joints after treatment for childhood cancers.”

Why surgery?

“The surgery is done to resurface the end of the thighbone (the femur) and the top of the leg bone (the tibia),” he says.

“This is where cartilage has worn away and where bumps and bony spurs called osteophytes have formed over the years.

“This is the result of the body trying to regenerate itself, but these osteophytes make the knee very rough and possibly deformed. The knee gets stiff then and you also have pain, so you have what we call lack of function.”

How it’s done

“We replace the worn cartilage with about a 9mm to 10mm metal coating (a pre-made, metal surfacing unit).

“Special instrumentation allows us to prepare special cuts at the end of the thighbone to prepare for and match the surface of the pre-made metal surfacing unit.

“The undersurface of the femoral component has a certain geometry and we create the same geometry at the end of the thighbone so the femoral component will fit on perfectly, like a glove. It is then grouted on with some cement.

“Likewise, you prepare the upper part of the tibia – the leg bone – for a special metal tray, then there is a plastic insert that goes in between the two and that allows the knee to move. The knee is a hinge joint and the constraint of the hinge – what controls the hinge – is your own soft tissue, your own muscles and ligaments.”

Are some operations more difficult than others?

“Yes. It depends on the degree of deformity and pre-existing trauma. Fractures may make the operation more difficult and sometimes we have to use other variants of knee replacements (units), but most of the time we can do it.”

“There is a perception out there that knee ops are less successful than hip operations. There is a little bit of evidence behind this in that the patient satisfaction scores for knee replacement operations are not as high as for hip replacements,” he adds.

“Hip replacement is one of those operations that have such a high success rate that it is a difficult yardstick to match. Still, knee replacement operations are nearly as successful. Generally, people do well after them and 90% are very, very happy.

“There are risks with every operation, but in a healthy person, or even someone who has underlying medical conditions that are well managed, it’s a very good operation.”

“The commonest complication that can occur afterwards is pain and there can be a difficulty with the rehabilitation in the early stages, including swelling and bruising.

“It’s a difficult process in the first six to 12 months following a knee operation, compared to a hip replacement. It is not more complicated from a surgeon’s point of view, but, for the patient, there’s a lot more involved in the rehabilitation process.”


Improvements in the operation have happened in the past 20 years but are not totally related to the basic implant.

“If I showed you a 25-year-old design of it and one designed eight years ago, you probably couldn’t tell the difference,” he says.

“There are only subtle changes. The biggest differences now are:

  • Our understanding of how to put the implants in.
  • Improved instrumentation
  • Better pre- and post-operative management of patients, for example, part of having a knee replacement operation is doing exercises before having it done.
  • Better pain relief during and after the operation.
  • Less swelling and bleeding (it is now unusual for a knee replacement patient to have a blood transfusion).
  • Length of hospital stay has reduced from two weeks in the past down to four or five days.

Aftercare tips

Denis Collins wouldn’t advise anyone to stop using crutches quickly after the operation.

“Most people could walk without them after a few days, but I wouldn’t advise that because their muscles are still tender and sore. We don’t want people falling or hurting themselves.

“I would advise using two crutches and being able to walk properly that way, rather than using only one crutch and walking poorly with a limp.”

* Orthopaedics is the branch of medicine that deals with the prevention and correction of injuries and disorders of the skeletal system and associated muscles, joints and ligaments.

For further information or to make an appointment with an orthopaedic surgeon email gp@sportssurgeryclinic.com or phone +353 526 2300

More News