To Knee Or Not To Knee
This article is designed to clear up the difference between two different types of knee surgeries. Punters often use the terms ‘knee reconstruction’ and ‘knee replacement’ interchangeably. This is a never ending source of amusement for medical types, who know that these are both completely different procedures, done for completely different reasons, on completely different types of people. But we all make mistakes (and medical nerds have to derive entertainment from somewhere), so don’t worry! Just read this article and you will not make the mistake again!
Knee Reconstruction
In short, a ‘Knee Reconstruction’ is performed to repair a torn anterior cruciate ligament, or ACL. The ACL is a ligament located deep inside the knee, and runs between the femur (upper leg bone) and the tibia (the main bone in your lower leg). It’s role is to stop the tibia from sliding too far forward when one suddenly stops running, twists on the knee, or walks downhill or down stairs.
The most common mechanism for rupturing an ACL is a sudden stop and twist on a sporing field. This is usually accompanied by the feeling of a snap or pop in the knee, and instant swelling. Interestingly, the athlete will often feel ready to play sport again after 5 or 10 minutes, but as soon as they go to stop suddenly or twist, the knee gives way and they retreat to the sidelines once again.
A completely ruptured ACL will not repair itself, and it must be surgically repaired if the person wants to return to sports. The ACL ‘victim’ is usually aged 18 to 50.
In a ‘Knee Reconstruction’ (often more appropriately called an ‘ACL reconstruction’), the surgeon will obtain tendon tissue from either the hamstring behind the knee, or the patellar tendon on the front of the knee, and use it to recreate the ACL ligament. The patient is often on crutches for a week or so afterwards, and will need Physiotherapy for about 12 weeks intensively, then less frequent checks around 6 and 9 months. Full return to contact sport is about 9 to 12 months.
Knee Replacement
In short, a ‘Knee Replacement’ is performed to replace a knee that is worn out – usually by arthritis from old age! A knee replacement candidate is someone who has had increasing pain in their knee from degenerative changes, to the point where it is impairing their normal daily function. A basic xray will confirm arthritis.
In knee replacement surgery, the end of the femur and the top of the tibia are removed, and replaced by prostheses – fake ones! The new, fake surfaces are lovely and smooth, as opposed to the old bumpy worn surfaces that get removed. This is quite major surgery with a much bigger scar than for the knee reconstruction, and patients are often on a frame, crutches and/or a walking stick for a number of weeks. Physiotherapy is imperative and extensive over about 12 weeks. It often takes a year for the knee to feel like ‘theirs’ again. The knee replacement ‘victim’ is usually over 50.
The prosthesis that gets inserted in a knee replacement generally has a life of 15 to 20 years, which is why surgeons are often hesitant to do this procedure on anyone much younger than 60.
Summary
So there you go, you will no longer be the butt of medical people’s jokes. For knee reconstruction, think footy players, and for knee replacement, think worn out knee.
Let’s hope you never need either!
If you have any further questions about this article, email me: karen@physios-online.com
Karen Finnin
Musculoskeletal Physiotherapist
BAppSc(Physio),MMuscPhys