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Recurrent (Chronic, Habitual, Congenital) Patella Dislocation
Dong Hoon Lee
What Is PatellarDislocation?
The patella can be dislocated.
There are different types of dislocation: ‘recurrent patella dislocation’, ‘habitual patella dislocation’, ‘chronic patella dislocation’ and ‘congenital patella dislocation’
Treating patella dislocation is a complex area in orthopedics. Congenital patella dislocation is especially complex, having a high recurrence rate and being more severe than traumatic patella dislocation. Causes of patella dislocation are not simple. They are very complex. If these factors are not treated appropriately, recurrence rate remain high even after surgery.
Donghoon Advanced Limb Lengthening Reconstruction Institute
We analyze all the underlying factors of the recurrent patella dislocation and treat properly according to the principle.
There are two main joints in the knee: the femoro-tibial joint (red arrow) and patello-femoral joint (yellow arrow).
The image below shows that the left patella is in place (yellow arrow), while the right patella is completely dislocated (red arrow). This is called ‘patella dislocation’.
The patella’s main function is to help the quadriceps muscle. Dislocation of the patella results in pain, disturbing walking and running motions. In the long term, it can cause arthritis.
There are many related factors. It would be simple if there were only one or two causes, but cases vary significantly. If not treated according to appropriate factors, it is difficult to get good results.
The incidence of patella dislocation is 6 out of every 100,000 people. This is a pretty high number. Habitual or congenital patella dislocation needs a surgical approach. But what about a first-time dislocation?
It depends on the case.
When the patella slips out, it crosses over the femur and such movement gives much stress to the patella. Cartilage injury rate is reported as 25-60%.
If the patient has conservative treatment after their first dislocation, the recurrence rate is 30-70%. However, we should not decide on surgery simply based on such rates
Finding out patient risk factors is important. Each patient has different conditions and underlying factors. The reason for a high recurrence rate is usually that such factors were ignored or not analyzed.
Donghoon Advanced Limb Lengthening Reconstruction Institute’s
Donghoon Advanced Limb Lengthening Reconstruction Institute’s failure rates are low because we consider underlying factors most importantly. If we are well informed about them, we can predict whether dislocation will recur or not. This should be the standard when we decide on surgery.
When the patella slips out, it crosses over the femur and such movement gives much stress to the patella, leading to cartilage injury. In severe cases, partial cartilage and bone fall out together. If this is the case, surgery is necessary even if it is a first-time dislocation. . You can see bone and cartilage falling out (arrow).
The area where it fell apart (red arrow) is clear in arthroscopic view.
In this case, the best theoretical treatment is attaching it to its original place. The problem is that it is not that easy. Donghoon Advanced Limb Lengthening Reconstruction Institute has techniques of using the patient’s own cartilage for treatment.
The image below shows that the injured part of cartilage completely healed 6 months after surgery
Osteochondral damage needs a surgical approach and reconstruction if possible
The causes of recurrent patella dislocation are bone alignment and problems with soft tissue, like ligaments and muscle. We need to discover major factors and treat accordingly. If not treated well, recurrence rates are high. Our target is to minimize long-term recurrence rates by treating underlying factors.
This is a 5 year old child. His patella has always been dislocated. It is chronic patella dislocation, not recurrent patella dislocation, and normal walking is difficult. You can see that it is totally dislocated (red arrow) compare to a normal patella (yellow arrow).
Chronic patella dislocation is the most complex case. Children have several risk factors which may lead to patella dislocation.
Dr. Lee performed 4 types of surgery, including bone correction surgery, and it brought good results. Above all things, it is important that we treat underlying risk factors and remove them.
The patella can be seen in its original place. Such treatment minimizes long-term recurrence rates.
This is a 16 year old adolescent. He experienced right patella dislocation for the first time 5 years ago. At that time, he received treatment with braces. Afterwards, dislocation occurred once or twice every year, yet he did not receive any treatment.
He says that he feels okay, but the x-ray below shows that the right patella (red arrow) slipped out halfway. On the left side, in which he never experienced dislocation, there is subluxation like the right side (yellow arrow).
There is a reason for conditions like this. Dr. Lee examined and found several risk factors. The patella was very unstable. He had a more detailed evaluation to confirm his risk factors, and treatment begun. He had 4 types of surgery, including corrective osteotomy on the tibia.
During surgery, we arthroscopically confirmed that the once tilted patella is now in place.
Causes of recurrent patella dislocation are complex. Treatment is also complex. Choosing the right treatment according to each factor is important.
This is a 15 year old adolescent. This case shows how important it is to treat underlying factors in patella dislocation treatment.
The patient visited another hospital because of recurrent patella dislocation and had surgery. Dislocation recurred after surgery, and she underwent another operation. However, it recurred again and she was sent to us.
At that time, she could not walk or bend her knee because of knee pain. The x-ray below seems to show normal leg alignment, but there are actually three types of deformity which caused the patella to dislocate.
Her underlying factors were bone deformities. We proceeded to do several evaluations for more accurate analysis.
She needed 6 types of surgery on one leg to reduce recurrence. The left patella was stable after surgery (yellow line) and the right side was still dislocated (red line).
After recovery of the left leg (yellow arrow), we proceeded to the right leg and now it is in place. She is now doing well without recurrence.
As such, we can gain good results and prevent recurrence by treating underlying factors.
This is a 45 year old man. He had patella dislocation and bowing legs. After examination, we found that he had bowlegs, genu recurvatum and rotational deformity in the femur and tibia simultaneously. His condition was complex, having 4 different types of deformity in one leg
As we expected, the location of the patella was not normal.
We made a plan to correct leg alignment and other risk factors at the same time.
After correcting the right leg, leg alignment and patella location returned back to normal. The patient said that his knee felt stable. We therefore decided not to perform ligament reconstruction.
You can see the patella in place in the corrected leg (arrow).
We performed the same surgery on his other leg. His bowlegs and genu recurvatum were well corrected and patella location is normal now.
