Surgery and non-surgical treatments for chronic knee cap dislocation and patella instability
Ross Hauser, MD, Danielle R. Steilen-Matias, MMS, PA-C
In this article, we will examine surgical and non-surgical options for the patient with recurrent patellar instability or chronic kneecap dislocation.
- As we do a lot of work with Ehlers-Danlos syndrome hypermobility type, if you are researching knee cap dislocation in children, please see this article Ehlers-Danlos syndrome hypermobility type.
Kneecap dislocation occurs when there is an impact injury to the knee significant enough to dislodge the kneecap. When this injury occurs there can be damage or complete disintegration of the medial patellofemoral ligament (MPFL) and medial patellotibial ligament (MPTL). When there is the complete destruction of the ligament(s), the patient will then decide if they will have a medial patellofemoral ligament and/or medial patellofemoral ligament and medial patellotibial ligament reconstruction surgery. But what if there is not complete ligament destruction? What if the ligaments are damaged or stretched, can they be repaired?
What we will discuss in this article the various options for treatment:
- Surgery for a completely disintegrated ligament that occurs with acute injury and dislocation
- No surgery for a completely disintegrated ligament
- Surgery for a medial patellofemoral ligament and medial patellotibial ligament partial tear or wear and tear damage
- Regenerative medicine injections for medial patellofemoral ligament and medial patellotibial ligament partial tear or wear and tear damage
Chronic patellar subluxation and dislocation
Many times people will reach out to us via email or phone call and they will tell us a story of an injury that they thought they recovered from only to have knee pain “show up,” one day. These stories go something like this:
I was in an accident years ago. My leg jammed into the floorboard. I first heard a popping sound and then felt intense pain. As I was able to walk on it and could “walk it off,” my doctor told me to watch for pain and then come in for an MRI. A couple of years passed, my knee did not give me any problems. Then my knee started to hurt. Slowly a nagging pain had developed with slightly increasing intensity as the weeks and months passed.
Finally, I went to the doctor for an MRI. Impression: PATELLAR SUBLUXATION.
I was sent off to 6 x 2 a week physical therapy. After 12 sessions, I did not really get any help. Another doctor focused on the medial patellofemoral ligament (MPFL) as my main pain was coming from the center or middle part of my knee. I was sent to another round of physical therapy, this time focusing on the patella. This helped more but not “all the way,” back. My doctor told me that to get all the way back, I should consider surgery.
The doctor’s textbook on patellar instability. You will understand patellar instability better if you understand it from your doctor’s perspective.
We are going to visit the National Library of Medicine online department and the August 2020 update of the publication Stat Pearls (1) for an overview of patellar instability. This chapter is a breakdown of current treatment ideas in dealing with patellar instability. Here is a summary, we have added parenthesis as brief explanatory notes:
“Patellar instability by definition is a disease where the patella bone pathologically disarticulates out from the patellofemoral joint (Your knee cap is dislocating and coming out of the groove). This most often involves multiple factors from:
- acute trauma,
- chronic ligamentous laxity (the knee ligaments have become weakened and are no longer capable of holding the knee cap in its proper place),
- bony malalignment (valgus alignment – you are knock-knee, femoral anteversion – you are “pigeon-toed”, tibial external rotation – you walk with your toes turned and pointed outward),
- connective tissue disorder (You may have a problem such as Ehlers-Danlos syndrome hypermobility type which we mentioned at the top of this article),
- or anatomical pathology (an injury or disease).
Overtime patients that have patellar instability can have debilitating pain, limitations in basic function, and long-term arthritis.” (You probably knew that already).”
Treatment guidelines: Nonoperative
- The majority of patella dislocations spontaneously pop back into place.
- activity modification,
- and physical therapy
- Patella sleeve – ‘J’ sleeve
- Patellar taping
These treatments work best with:
- First-time dislocation or chronic dislocations.
- No loose bodies (pieces of cartilage, soft tissue, and bone chips floating around in the knee) or articular (cartilage) damage
- No osteochondral fragments (pieces of bone or cartilage floating around following an acute injury)
- Patients with connective tissue disease – Ehlers Danlos
On Physical therapy, the treatment is described as: “Physical therapy should focus on closed chain exercises (an exercise such as a push up where the furthest part of a limb remains stationary while you perform the exercise) and quadriceps strengthening. Core hip strengthening and gluteal muscle strengthening will improve external rotators of the hip, thus externally rotating the femur and decreasing the Q-angle. (The Q-Angle is the angle of the hip-to knee typically pronounced in women because of childbearing).”
Patella dislocation surgery
This guide of treatments now continues on with the surgical aspects.
General indications for surgery:
- Osteochondral injury with loose body
- Chronic instability
- Failure of nonsurgical treatment
The surgical options, which many of you may have already discussed with your orthopedic surgeon may include:
- Arthroscopic debridement with removal of loose bodies
- Putting the knee cap back in place and holding it there with screws and pins
- Medial patellofemoral ligament (MPFL) repair
- MPFL reconstruction with autograft versus allograft
- Osteotomy (bone reshaping)
Deciding on treatments
Many people get great benefits from conservative care and surgical repair of patella instability or their chronic knee cap dislocations. For the majority, surgery can be very successful. These are typically the people we do not see at our center. Let’s point out here that if you have a surgery that has failed, it will be very likely that moving forward you will need more surgery to fix the problem. Treatments such as conservative care and injection therapy will have limited success if screws and pins have been inserted or other radically anatomic changes have been made to the knee.
Surgery for a completely disintegrated ligament that occurs with acute injury and dislocation.
What we are going to look at first is the injury that occurs when the knee suffers a blow that knocks the kneecap out of its groove. When this injury occurs almost always the medial patellofemoral ligament is completely ruptured. Ligaments connect bones to bones. The medial patellofemoral ligament connects the lower thigh bone to the back of the patella/kneecap. So it is easy to see when the kneecap is dislocated, this attachment snaps.
- At this point, a decision must be made on treatment. First, we will look at the surgical treatment.
The first treatment decision is obviously to get the kneecap back in place and secure it.
- Your doctor may recommend surgery to repair or reconstruct the medial patellofemoral ligament. He/she will refer to it as your MPFL.
If this is your first kneecap dislocation, the decision to go to surgery will come with a degree of urgency. Surgeons believe that they only get one chance to perform a repair to your original ligament. After repeated dislocations, the original ligament cannot be surgically repaired, It must be reconstructed from a tendon or ligament that the surgeons get from somewhere else in your body.
- The points to consider here and that will be documented in the research below:
- The ligament can only be repaired in a partial tear or rupture situation
- If the ligament suffers a total rupture/disintegration – then the surgery does not repair, but reconstruction.
- These surgeries have been shown that they do not decrease future dislocation risk. (This is something we will discuss below, an isolated repair cannot guarantee future knee stability).
In this October 2018 research, we see surgeons talking to surgeons in the medical journal Arthroscopy. (2) Let’s join the conversation:
The purpose of this research is to “clarify the discrepancy in surgical options and present evidence to treat patellar dislocation by evaluating which of the (surgical) techniques yields better improvement in stability and functional recovery for patellar dislocation.”
In this research, military and university researchers in South Korea shared with the international surgical community these findings:
- Eleven clinical studies were investigated to determine the effective outcome of surgical versus non-surgical treatment
- In patients with acute patellar dislocation, there were no significant differences in all evaluated outcomes between the conservative and surgical treatment groups.
- For patients with recurrent patellar dislocation, MPFL reconstruction was associated with better outcome scores than compared with soft tissue realignment surgery.
Surgical treatment of the MPFL for acute patellar dislocation is not superior to conservative non-surgical treatment in restoring knee function and clinical outcomes
- Surgical treatment of the MPFL for acute patellar dislocation is not superior to conservative non-surgical treatment in restoring knee function and clinical outcomes
- MPFL reconstruction is associated with more favorable clinical outcomes compared with medial soft tissue realignment surgery in patients with recurrent patellar dislocation.
- MPFL reconstruction is the better of surgical treatment strategies, once the patient decides that they want the surgery anyway.
The bottom line: Surgeons are reporting to surgeons that non-surgical technique is in fact just as good as surgery.
Acute Patella dislocation | Traditional non-surgical conservative care | Immobilization and rehab
Now we are going to get into even more controversy surrounding the treatment of patella dislocation. The conservative non-surgical treatment option. This is not to be confused with the non-surgical regenerative medicine option we will discuss below.
A well-cited paper from the Department of Orthopaedics, Southern California Permanente Medical Group was published in the journal Sports Health. What the doctors were looking for was to provide guidelines, A Treatment Algorithm for Primary Patellar Dislocations, (3) which was the title of their paper. Here is what they said:
“Surprisingly little evidence exists addressing the nonoperative treatment of the primary patellar dislocation. Contemporary treatment regimens range from immediate mobilization without a brace to cast immobilization in extension for 6 weeks.”
Here are some of the issues they came across:
- Immobilization in extension (your knee is fixed in a straight leg position) may give the MPFL a better environment in which to heal. However, this comes at the expense of stiffness, weakness, and loss of limb and proximal control that often accompany prolonged immobilization.
- Patient compliance can also be a factor in deciding nonoperative treatment. For these reasons, many clinicians advocate a short period of immobilization, followed by rehabilitation of the knee, with or without a patellar brace.
- Although the management of the primary patellar dislocation remains a topic of considerable controversy, certain conclusions can be drawn. If a hemarthrosis (bleeding in the knee) is present, patients should be evaluated for osteochondral fractures (damaged to the cartilage and bone underneath).
- Acute surgical stabilization remains controversial, with no clear long-term benefits demonstrated in the literature.
- If nonoperative management is elected, a period of immobilization in extension up to 6 weeks will yield the lowest redislocation rate.
- In sum, this algorithm provides an evidence-based approach that assists the clinician in the treatment of the acute first-time patellar dislocation.
It is clear from these two representative studies why acute patella dislocation usually becomes a situation of chronic patella dislocation
Surgery for chronic patella dislocation – does this surgery help a 16-year-old athlete? Surgery judged ineffectively
Doctors in Germany at Münster University Hospital wrote in the journal BMC Musculoskeletal Disorders (4):
- There is currently no consensus regarding the optimal surgical treatment method for patients with recurrent patellar instability. (Chronic patella dislocation).
The goal then of their study was to evaluate the long-term results of combined arthroscopic medial reefing (reconstructive surgery of the supporting connective tissue of the patella) and lateral release (surgery to put the patella back into its correct position.)
The average age of the patients at the time of surgery was 16 and comprised of adolescent athletes. The youngest patient in the study was 9. The patients were followed for about 5 – 15 years post-surgery.
- The pain continued post-surgery: Residual complaints were present in 34 cases (79%).
- Dislocation continued post-surgery: Twenty-two cases had recurrent dislocation after a median interval of 30 months. The probability of recurrent dislocations amounted to 16% after 1 year and 52% after 10 years.
- Surgery judged ineffectively: The combined arthroscopic lateral release with medial reefing does not appear to be an adequate treatment for patients with chronic patellar instability in long-term follow-up.
- Younger patients might be at a higher risk for recurrent dislocations.
Why Do Patellofemoral Stabilization Procedures Fail?
Doctors in the United Kingdom said it more simply in their paper published in the Sports medicine and arthroscopy review. They asked Why do patellofemoral stabilization procedures fail?
In recent years, surgical interventions for patellofemoral joint instability have gained popularity, possibly revitalized by the recent advances in our understanding of patellofemoral joint instability and the introduction of a number of new surgical procedures. This rise in surgical intervention has brought about various complications. (5)
Patellofemoral instability surgery success rates?
- Doctors note that many treatments can make symptoms of patellofemoral instability and pain worse in some patients.
- One paper says more than 25% of patients had significant side effects after surgical treatment of patellofemoral instability.
Physiotherapist Jenny Mcconnell wrote in the medical journal Manual Therapy (6) that:
Some cases of patellofemoral instability are difficult to manage and, in fact, some treatments can make the patient feel worse. Frequently, the patient often bounces from practitioner to practitioner, physiotherapist to the surgeon, seeking some relief of symptoms. However, their underlying source of pain is not well understood, so treatment can aggravate the symptoms.
Doctors have put a lot of emphasis on medial patellofemoral ligament (MPFL) reconstruction for the treatment of recurrent patellar dislocations/subluxations. Numerous techniques have been reported; however, there is no consensus regarding optimal reconstruction and in one paper a total of 164 complications occurred in 26% of patients. Side effects included patellar fracture, failures, and clinical instability on postoperative examination, loss of knee flexion, wound complications, and pain.
What are we seeing in this image?
We see that the patella sits in its groove in the knee and is held there by the tension created by the various pulling forces to hold it there. Think of the tension on a trampoline. The tension is created by the force of the springs, cords, or ropes that keep the trampoline material tight with the frame. For the patella to remain in its groove, the forces that pull it to the left must be counterbalanced with the forces that pull it to the right, the forces that pull it up must be counterbalanced with the forces that pull it down.
Instability can occur if the left side pull is stronger than the right side pulls because of ligament damage or other injuries to the right side structures. Instability can occur if the forces that pull the patella down are stronger than the forces that hold the patella up.
Like a trampoline, if one side of the tension is off or damaged, the trampoline will lose its tension, stability, and function.
Patellofemoral instability – not addressing the whole knee leads to surgical complications
This is why, when addressing the problem of patella instability, we must address the whole knee, the right and light side to keep the proper tension, the up and down, to keep the proper tension and the patella in its groove.
A highly cited study in The American Journal of Sports Medicine from doctors at the University of Kentucky, Department of Orthopaedic Surgery and Sports Medicine also suggests that patients with medial patellofemoral ligament reconstruction without additional stabilizing treatments suffered from a high rate of continued problems including 5% who continued with recurrent dislocations. (7)
In the March 2016 issue of Arthroscopy, university and researchers in Rome working with the Harvard Medical School found conflicting evidence for the use of Medial Patellofemoral Ligament Reconstruction combined With Bony Procedures (bone reshaping) for Patellar Instability. Enough so that they were unable to identify an absolute indication for this type of surgery. (8)
This supports research from the Mayo Clinic published in the American Journal of Sports Medicine that says when you have multiple knee ligament damages – such as in degenerative wear and tear or acute injury – the medial patellofemoral ligament plays a very insignificant role in knee instability and does not even need to be addressed. (9) Of course to a doctor experienced in regenerating ligaments, all ligaments play an important role. In surgery, many times supportive tissue is discarded.
As we are discussing here, the problem of chronic dislocation is a problem of multiple weakened or damaged structures that pulls the knee cap out of place or the groove itself is damaged. In August 2021 doctors writing in the journal BioMed Central musculoskeletal disorders (10) wrote: “After first-time patellar dislocation, the dynamic position of the femur in relation to the tibia plays an important role in joint stability, because the medial stabilizer of the patella (the Medial Patellofemeral Ligament) is damaged or inefficient. The most important factor in controlling the rotational movement of the tibia in relation to the thigh are the hamstring muscles. . . . In patients with recurrent patellar dislocation, knee flexors strength is decreased significantly in both the unaffected and affected limbs. This may indicate a constitutional weakening of these muscles which can predispose to recurrent dislocations.”
Athletes with pain often feel there is no other choice but a surgical procedure, even a drastic one
Athletes with pain often feel there is no other choice but surgical procedures, even drastic ones. A good example of drastic surgery is the recommendation to surgically remove the patella in order to remove the pain. This sometimes does relieve the pain, but at a significant cost to the body. The strength to extend the knee is reduced by about 30 percent, and the force exerted in the knee is increased.
There are a host of other risks associated with surgery. The patient must realize that with each procedure and each shaving or cutting of tissue, NSAID (non-steroidal anti-inflammatory drug) prescription, or cortisone shot, the odds of developing long-term arthritis are greatly increased. The key to keeping the knee strong is to stimulate the area to heal, not to cover up the pain with a cortisone shot or NSAID. Even worse is to eliminate the painful area by shaving or cutting. This just delays the pain for a few years until the remaining tissue becomes degenerated. The best approach for the athlete is to stimulate the area to heal.
And if the surgery does not work?
This is a January 2021 study in the journal Knee surgery, sports traumatology, arthroscopy (11). It simply states: “Patients unable to return to play following medial patellofemoral ligament reconstructions demonstrate poor psychological readiness.” Let’s look a little closer at these findings:
“Medial patellofemoral ligament reconstruction is often indicated in athletes with lateral patellar instability to prevent recurrence and allow for a successful return to play. In this patient population, the ability to return to play is one of the most important clinical outcomes. The purpose of the current study was to analyze the characteristics of patients who were unable to return to play following medial patellofemoral ligament reconstruction.
A retrospective review of patients who underwent medial patellofemoral ligament reconstruction and subsequently did not return to play after a minimum of 12-months of follow-up was performed.”
Findings and conclusions:
- The study included a total of 35 patients who were unable to return to play out of a total group of 131 patients who underwent medial patellofemoral ligament reconstruction as a treatment for patellar instability.
- Overall, 60% were female with a mean age of 24.5 and an average follow-up of 38 months.
- The most common primary reasons for not returning to play were:
- 14 were afraid of re-injury,
- 9 cited other lifestyle factors,
- 5 did not return due to continued knee pain,
- 5 were not confident in their ability to perform,
- and 2 did not return due to a feeling of instability.
- “Conclusion: Following MPFL reconstruction, patients that do not return to play exhibit poor psychological readiness with the most common reason being fear of re-injury.”
The regenerative medicine option. Prolotherapy injections to pull the kneecap into place and keep it there.
In the research above you see that a first-time dislocation of the kneecap creates short and long-term problems of knee instability which leads to long-term problems of chronic patella subluxation or simply, chronic dislocation of the kneecap. This is also referred to as patellofemoral tracking syndrome. This is where the kneecap floats out of the groove on the femur (thigh bone) it is supposed to sit and glide up and down on.
As we have seen in the research above, this can equally affect an adolescent athlete as well as an older athlete. The kneecap is supposed to stay in the middle of the knee, in its groove. But because of past dislocations or advanced knee instability, the kneecap wanders to the sides. When this occurs not only is there a problem of the maltracking patella, there is also a problem of accelerated wear and tear and the development of osteoarthritis. This can also lead to a problem of Patellofemoral Pain Syndrome.
Caring Medical Research on Prolotherapy treatments for patella disorders and knee instability
Our Caring Medical staff has published many research papers on using Prolotherapy for various musculoskeletal disorders. You can find that research on our Prolotherapy research page.
In 2014, we published in the journal Arthritis and musculoskeletal disorders our paper: Outcomes of Prolotherapy in Chondromalacia Patella Patients: Improvements in Pain Level and Function. (12) Below are the summary highlights.
- Chondromalacia patella, the result of osteoarthritis in the knee, can be age-related or due to trauma. Prolotherapy in this group of 69 knees showed statistically significant improvements in pain at rest and with activity.
- Functionality was improved by evidence of:
- increased range of motion,
- walking ability, and
- exercise ability.
- Improvements in pain, range of motion, stiffness, and crepitus were sustained in over 92% of patients. Pain medication usage also was decreased following prolotherapy.
Specifically, with prolotherapy:
- there was a substantial decrease in the number of knees with modestly worse to severe pain at rest from 11 knees (15.9%) to 0 knees (0%) and in those knees with modest pain at rest from 13 knees (18.8%) to 2 knees (2.9%).
- More knees had no pain or minimal pain at rest following prolotherapy compared to before treatment.
Return to activity and exercise
Prolotherapy had a notable effect on the potential for pain-free activity and exercise. After prolotherapy, there was a substantial increase in the number of knees reported to have no pain or little pain upon activity from 22 knees (31.9%) to 67 knees (97.1%).
A decrease in the number of knees experiencing moderate pain was also observed from 24 knees (34.8%) to 4 knees (5.8%). Initially, 23 knees (33.3%) produced severe pain during activity, but no patient experienced severe pain after prolotherapy. Overall, this reduction in pain during activity was statistically significant.
Similarly, upon exercise and before prolotherapy, 42 knees (61.8%) of patients developed severe pain and 16 knees (23.5%) produced moderate pain.
After prolotherapy, only 2 knees had severe pain upon exercise and 9 knees sustained moderate pain.
Fifty-nine knees (86.8%) had no pain or minimal pain during exercise after prolotherapy compared to 10 knees (14.7%) without pain before prolotherapy. The alleviation of pain upon exercise compared to the pain before prolotherapy was also statistically significant.
At least 75% of prolotherapy effect on pain relief lasted in 62 knees (89.9%) following treatment. Only 1 patient stated that pain relief from prolotherapy did not last.
The results of this study confirm the findings of our previous study of 119 knees in 80 patients, in which more than 82% of patients showed improvements in walking ability, medication usage, athletic ability, anxiety, depression, and overall disability following prolotherapy injections for unresolved knee pain. In that study, patients were provided prolotherapy of 20–40 injections every 3 months and then evaluated at 15 months. As in this study, 96% of patients felt that prolotherapy had improved life overall.
The results of this study suggest that prolotherapy in the treatment of chondromalacia patella is associated with substantial gains in pain relief and functionality. As prolotherapy is a simple, rapid, and low-morbidity option for use in the outpatient setting, it can be considered first-line conservative therapy for chondromalacia patella. The application of prolotherapy to chondromalacia patella, a rheumatological disease in need of definitive therapy, warrants further investigation.
What are we seeing in this image?
Here we have the “sunrise” image of a before and after Prolotherapy treatment. The alignment and stability in this patient’s knees were greatly improved. She was able to run again. As with any medical technique, there are successes and failures. This treatment may work for you on varying degrees of success levels. This treatment may not work for you.
What are we going to see in this video?
Ross Hauser, MD demonstrates a comprehensive Prolotherapy treatment to the knee in a patient with patellofemoral pain syndrome and poor patella tracking caused by knee instability. Because this patient is an avid hiker, frequently walking on uneven ground, the ligament attachments need to be treated along the lateral, and medial sides, as well as along the patellar tendon attachments. She has responded very well to Prolotherapy over the years, which has enabled her to be active. Otherwise, as the patient tells us, she would likely not be able to walk at all due to the various joint instability injuries that have occurred because of her hypermobility.
Summary and contact us. Can we help you?
We hope you found this article informative and it helped answer many of the questions you may have surrounding your knee cap problems and patella instability. If you have questions about your knee pain and how we may be able to help you, please contact us and get help and information from our Caring Medical staff.
Brian Hutcheson, DC | Ross Hauser, MD | Danielle Steilen-Matias, PA-C
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This article was updated August 31, 2021