THE HEALTH | SEPTEMBER , 2023

BONE TO PICK

The bone I am referring to is the patella , more fondly referred to as the knee cap . Nestled at the front of the knee joint , it sits between the thigh and leg bones .

The patella is enveloped by the tendons that are on the upper and lower parts of it . These tendons are called the quadriceps and patella tendons . Extension or straightening of the knee depends on the proper function of these tendons .

The patella enhances this function by increasing the lever arm and thus expanding the vector of the pull of the tendons . This little bone significantly increases the strength of knee extension . Studies have shown that removing the patella will reduce the power by up to 30 per cent .

One of the more commonly encountered problems concerning this bone is dislocation of the patella . It can occur due to trauma or , less typically , due to anatomical abnormality of the structures that keep it stable . So , let us take a step back and examine these structures .

Starting from the inside , this ovalshaped bone glides between a groove formed by the thigh bone in the knee . This valley-shaped groove is called the trochlear groove . The trochlear groove is like two mountains , between which is the valley .

And instead of a river running through it ( like a scenic painting ), the patella glides between them . However , in certain patients , these mountainlike structures are not formed properly . Because of this , the patella tends to slide outwards and out of position instead of sliding between them like it is supposed to .

CLINICAL HISTORY

The following structure is the ligament that holds it in place , called the medial patellofemoral ligament ( MPFL ). This ligament acts as a check-rein to keep the patella in place , similar to the check-rein used in horse riding .

Running from the patella on its medial side , injury to it can result in the patella dislocating to the side . The final structure that plays a significant role in stabilising the patella is the quadriceps muscles , more specifically ,

a part of the muscle called the vastus medialis obliqus ( VMO ).

This is a fancy name for the muscle above the patella on its medial side , keeping it in place with muscle tone and during contraction . As with any other orthopaedic condition , patella dislocation diagnosis can be made clinically based on the history .

As mentioned above , patella dislocation can be a result of trauma ( like a fall or a sporting injury ) or because of anatomical abnormalities . In any case of patella dislocation , the immediate treatment would be to reduce the dislocation or , in other words , to put it back where it is supposed to be .

Further treatment in terms of surgery depends on many factors . For example , your doctor might ask , how often has this happened before ? It is because the patient will need to be treated operatively in cases of recurrent dislocations . This is where this article gets the name of its title from .

Diagnosing a patella dislocation

Diagnosing a patella dislocation is just the beginning . Identifying the root cause of why it is happening is where things get a little bit tricky .”

is just the beginning . Identifying the root cause of why it is happening is where things get a little bit tricky . By now , we already know that multiple

Dr Jonas Fernandez is an Orthopaedic Surgeon at Putrajaya Hospital . He is also a member of the Malaysian Arthroscopy Society ( MAS ). anatomical structures are responsible for maintaining the patella ’ s position .

So , how will your doctor determine which structures are causing the problem ? It is done by thoroughly examining the patient as a whole and the affected limb .

One will need to identify , through physical examination , if the patient has generalised laxity of the joints , meaning if they are “ loosely jointed ”, to check if the patella can be pushed in and out of position and if the patient ’ s limb is malrotated in any way .

TREATING THE UNDERLYING CAUSE

This , coupled with imaging studies such as X-rays , CT scans and MRI scans , will be able to guide the doctor toward the best treatment plan .

Before any surgery is considered , patients should undergo a period of physiotherapy that should focus on strengthening the core and the quadriceps muscles and the muscles around the hip . These will help strengthen the muscles that function as dynamic stabilisers of the patella .

Surgical treatment , on the other hand , will aim to correct any anatomical abnormalities detected . This is done by reconstructing the MPFL . In addition , further correction of the bony structures around the knee might be necessary .

Apart from patella dislocations , another common condition seen is patellofemoral arthritis . This is a condition whereby the cartilage on the patella is worn out . Although this condition is expected in senior citizens , it can also be seen in patients in their 30s .

This is because , like in patella dislocation , anatomical abnormalities might cause the patella to not glide smoothly on the underlying trochlear . It would eventually lead to their cartilage being worn down . Treatment of cartilage defects were covered in my previous article , titled The Slippery Slope .

However , treating the underlying cause of it , as with patella dislocations , will require thorough examination and meticulous planning . This is because treating conditions affecting the knee cap often requires putting on the thinking cap . – The Health