Some basic anatomy
The knee joint is constructed in such a way that it depends on several ligaments to maintain its integrity. The bony anatomy balances one knuckle shaped bone (femur) on another fairly flat bone (tibia) and on that rather unlikely surface we put all our weight, trusting that all is secure. Most of the time it is, thankfully, due to both the ligaments and to the strength and coordination of muscles at the front (quadriceps) and back (hamstrings) of the thigh.
The surface of the joint is further deepened by two crescent shaped menisci or cartilages that sit on top of the tibia. This adds more stability to the joint and provides extra shock absorbance.
Ligaments are rather like tough elastic bands. Their job is to stop the joint from being moved too far. They have a poor blood supply and therefore heal slowly.
The main ligaments of the knee are as follows:-
- Lateral ligament: this runs down the outer side of the knee and prevents over stretching of the outside of the knee
- Medial ligament: this goes down the inner side of the knee and helps to prevent over stretching of the inner aspect of the knee.
- Cruciates: There are two of these and they are in the middle of the knee between the knuckles of the femur. They prevent excessive gliding of the tibia in both a backward and forward direction. The two ligaments cross over within the joint, hence their name!
Mechanisms of injury
The commonest way to injure either ligament or cartilage is to have most of your weight on the leg with the knee bent and then to twist or be twisted forcefully. It is more common to sprain the medial than the lateral ligament. Pain is normally immediate with ligament injuries and the joint swells within a few hours. Cruciate injuries often involve a sudden deceleration or a slow sitting back manoeuvre, particularly common in skiing debacles. Menisci or cartilages are damaged in the same way as ligaments and injury can vary from a mild fissuring to major tears where a loose flap developes that blocks the joints' movement.
Immediate treatment
- Ice and elevation
Put ice on for 15-20 mins, 3 times a day When using ice, the best way is to use ice cube bags. Wet a tea towel or piece of kitchen towel and put that around the knee first, followed by the ice. Wrap the whole lot with a dry towel and elevate the leg so that the foot is higher than the knee. - Analgesia
Use either as prescribed or begin with 2 paracetamol 4-6 hourly and seek medical advice if that is insufficient - Exercise
Some form of exercise should be started within 48 - 72 hours of injury because the thigh muscles will begin to weaken immediately.
The most simple exercise suitable for almost every injury is to lie with the leg outstretched and tighten the thigh muscle so pushing the back of the knee down onto the bed/couch etc. If this is impossible take two or three paper back books covered with a towel, put this under the knee and try again! Try to do at least 10 repetitions 3 hourly. If that is easy increase the number of repetitions until it isn't!
Keep using the ice until the swelling has almost gone. All the time there is significant swelling it will be impossible to bend the knee fully and the thigh muscles are inhibited from working properly.
It is vital to regain full muscle strength as soon as possible. The quadriceps on the front of the thigh are responsible for the dynamic stability of the joint. They prevent the knee from giving way, they are also superb shock absorbers and obviously the stronger they are the more efficient they are at performing this role. It is very important that specific exercises are done to regain strength. Walking is insufficient as a strengthening exercise. A physiotherapist will give you a progressive exercise regime suitable for you to do at home or even in the office!!
Surgery
If some reparable damage is thought to exist in the joint, an arthroscopy will often be done first. This is a small telescope that is inserted into the joint to specifically identify what structures are at fault and whether further surgical procedures are necessary.
If a meniscus(cartilage) has been significantly damaged, the damaged section will often be removed via the arthroscope. Recovery is rapid and only necessitates a couple of days in hospital, sometime less.
Torn cruciates are sometimes repaired surgically, if the knee is deemed unstable despite intensive physiotherapy or if the persons job or level of sport demand put an extraordinary strain on the joint.
A joint that has some arthritic change in it may improve by having the joint washed out. This is also done surgically.
When a joint is so severely affected by arthritis that joint replacement is the only viable alternative.
Pain around the knee cap
This typically happens in the following situations:-
- In young people aged between 12 and 24, often having just undergone a sudden growth spurt and/or are excessively mobile.
- In people who start from being very unfit and try to do too much too soon.
- In people who have had enforced immobility e.g leg in plaster, hip or knee joint replaced, the muscles then become weak.
The pain is normally caused by a weakness in the muscle on the front of the thigh which controls the movement of the knee cap. When the muscle is weak the knee cap is pulled by other structures into a painful position which is made worse by certain movements e.g going down stairs or hills, sitting with the knees bent and then having to get up.
A very effective treatment for this is a proper assessment by a physiotherapist who will then show you appropriate exercises and if necessary some specific taping techniques.
It is a common problem, but one that can be dealt with easily in the majority of cases.
The majority of knee problems benefit immensely from specific regular exercise. Some will resolve completely with this approach, particularly in the early stages when it will help prevent the development of more severe symptoms.
More guidance
You can read more guidance notes in our common conditions section.
Contact us
If you would like to make an appointment or require further advice please email us or phone on 01892 785095 (Wadhurst) or 01892 668968 (Crowborough).