Swollen knee: what’s the cause?

The increase in the amount of intra-articular fluid is often referred to as knee effusion. The severity and urgency of the clinical picture will depend on the original cause.

What are the main causes of knee effusion?

This clinical picture may result from different causes, including direct or indirect trauma (knee sprains or twists), synovial diseases, the existence of a degenerative disease and infections, or septic arthritis.

In the case of post-traumatic knee effusion, sprains or physical overexertion, the cause may be:

  • Torn knee ligaments
  • Meniscal injuries
  • Degenerative diseases
  • Joint fractures

Secondary knee effusion can also emerge from systemic diseases (diagnosed or undiagnosed) such as:

  • Rheumatoid arthritis
  • Septic arthritis
  • Gout
  • Pseudogout
  • Transient synovitis

What to do when joint effusion occurs

After a sprain: If the effusion appears after trauma or spraining, it is advisable to rest the limb immediately, use crutches to walk, and apply a cold pack to the knee every two to three hours, while avoiding direct contact with the ice to prevent burns on the skin.

The patient should then seek emergency care as soon as possible, where they will perform necessary examinations and additional tests.

If severe effusion occurs, joint aspiration will control the pain significantly. It will also help determine a possible diagnosis, based on the contents of the evacuated knee (haematic, synovial, etc).

Postoperatively: Sometimes, as with postoperative processes, inflammation or knee effusion can occur, which may also result in an increased local temperature of the knee and the body. This clinical picture is to be expected, in isolation, within the first seven to ten days after the operation. It not recommended to take any antibiotics without first seeking medical care to undergo, when necessary, a joint aspiration (arthrocentesis) and a joint fluid culture. The appearance of the symptoms described above is often a result of the postoperative inflammatory process, without any relation to an infectious process. It is recommended to monitor the situation closely and remain vigilant, while also regularly monitoring the body temperature.

In degenerative knees: When a patient has a history of degenerative joint disease that leads to knee effusion, they should rest, take the weight off the joint by using crutches and apply ice to the injured area. If effusion occurs when the knee is under tension, the patient should see a specialist, undergo joint aspiration and monitor the progress of the joint.

Diseases of synovial membrane: There are different diseases that affect the synovial membrane and that frequently result in knee effusion, whether synovial fluid or with haematic content (hemarthrosis). When this occurs and in the case of it being practically spontaneous with no apparent cause for joint effusion, a specialist should undergo a puncture of the knee joint. Additionally, images should be taken for review, such as X-rays and MRI to find a specific diagnosis. Occasionally, it may be necessary to refer the patient to rheumatology.

How to avoid effusion when a degenerative joint is involved

When joint effusion is associated with a degenerative process, there are measures to protect the joint and reduce the risk of the knee swelling.

These are:

  • Keeping one’s body weight under control
  • Avoiding high-impact exercise
  • Strengthening periarticular muscles, performing stretching exercises, doing kinaesthetic exercises and maintaining proper joint balance
  • Apply a cold pack to the local area after exercise.

Equilae’s scientific work continues to receive national and international recognition

This May in Santander, the 7th joint AEA-SEROD Conference was held, one of the most important events in the field of arthroscopy and knee surgery—on both a national and international scale.

Equilae saw its members actively participate in various roundtable discussions and training courses. They also presented several projects in different formats (oral presentations, posters and video stream), covering the entire surgical field of knee pathology.

Once again, our team has been honoured with several awards:

  • The prize for ‘The Best Oral Presentation on Arthroscopic Knee Pathology’: In-vivo analysis of controlling rotational instability via the modified Lemaire anterolateral tenodesis, performed in isolation, presented by Dr Simone Perelli.
  • The prize for ‘Best Video Stream of the Conference’: Biological patellofemoral prosthesis. Fresh osteochondral transplantation for the patellar and trochlear surfaces, presented by Dr Maximiliano Ibañez.

Dr Simone Perelli  – ‘In-vivo analysis of controlling rotational instability by modified anterolateral Lemaire tenodesis, performed in isolation’

Dr Maximiliano Ibañez  – ‘Biological patellofemoral prosthesis.’ “Fresh osteochondral transplantation for the patellar and trochlear surfaces”

We also received new recognition during the 23rd International Conference for the Mexican Association of Articular and Arthroscopic Reconstructive Surgery (AMECRA). Here, the spotlight shone on Dr Christian Javier Sánchez Rábago, from Mexico’s Ángeles León hospital, who attended an on-site training course at Equilae between June and November of 2017. During his time on the team, he collaborated on the research project ‘Isolated, implant-free reconstruction of the medial patellofemoral ligament with elastic femoral fixation in case of patellofemoral dislocation’, which was presented and awarded first place in the Podium category.

Dr Christian Javier Sánchez Rábago receiving the award from AMECRA, alongside Dr Joan Carles Monllau, head of the Unit of Arthroscopy and Knee Surgery at ICATME, Equilae Group.

At Equilae, we believe that the exchange of knowledge and experience is one of the best ways to grow. This premise has always been the cornerstone of the fellowship program, and it has yielded results year in, year out.

The recognition and awards we have received fill Equilae with pride, demonstrating our ability to contribute towards the training of great professionals and to encourage a level of teamwork that transcends boundaries.


Equilae, pioneers the use of a new technique to reconstruct the anterior cruciate ligament in children

In Europe, Equilae has pioneered the use of a new technique to reconstruct the anterior cruciate ligament in children, which had previously only been used in Australia.

The technique involves the transplant of a hamstring tendon from one of the child’s parents. This not only reduces surgical invasiveness for the paediatric patient, but also avoids the risk of the new tendon having insufficient diameter or length. Such risks are fairly common in preadolescents and have been linked to increased rerupture rates of the ligament in the future.

Since the tendon is donated by one of the patient’s biological parents, the risk of transplant rejection can be avoided. In addition, the implementation of specific technical methods during the surgery prevents damage to growth plates and its potential impact on the child’s future growth and development.

These technical modifications, carried out during the reconstruction of the child’s ligament, allow the knee to be effectively stabilised. This avoids the occurrence of meniscal or cartilage lesions, as well as possible premature wear of the joint.

Dr Joan Carles Monllau García is head of the Knee and Arthroscopic Surgery Unit of ICATME, and of the Orthopaedic Surgery and Traumatology Service at Hospital del Mar. He is also a member of Equilae. In recent interviews with TV3 and La Vanguardia, he explained what this reconstruction technique involves.

As always at Equilae, we will continue to conduct research in pursuit of the best results through the least invasive methods.


10 things you should know about the anterior cruciate ligament

What is it and what does it do?

The anterior cruciate ligament (ACL) is one of the four major stabilisers of the knee, forming the ‘central pivot’ along with the posterior cruciate ligament (PCL).

It is the main anterior stabiliser of the knee, preventing the tibia from sliding forward on the femur, as well as controlling hyperextension and internal rotation.

How do ACL injuries occur?

Although they can occur in various everyday activities, anterior cruciate ligament injuries are usually related to practicing sports: especially those that require pivoting, such as football, basketball, skiing and rugby.

They tend to occur through self-injury, meaning that the individual’s own movement is the only factor involved. ACL injuries can happen when landing from a jump or changing direction, and when performing any movement that involves contraction of the quadriceps, valgus motion, flexion or external rotation.

What are the symptoms of an ACL tear?

In an acute setting, the individual often experiences intense inflammation of the knee or hemarthrosis (accumulation of blood in the knee), accompanied by pain and a limited range of motion.

After this acute process, the pain decreases and the symptoms of ‘failure’ (joint instability) set in when rotating the knee, doing routine movements or carrying out everyday activities. This is the consequence of tearing one of the knee’s major stabilisers.

What are the risks associated with an ACL tear?

After tearing the ACL, the individual may experience episodes of instability or a sensation of ‘knee failure’ (this is how many of our patients describe it). This results in an increased risk of meniscal tears and cartilage damage, which can lead to the development of arthrosis in the long term.

Do all ACL injuries require surgery?

Surgery is necessary in most cases, as it is the only way to normalise the knee’s stability. However, for patients with low physical demands who do not experience episodes of instability during everyday activities, a conservative or non-surgical treatment may be prescribed.

What techniques are used to reconstruct the ACL?

There are various techniques for anterior cruciate ligament reconstruction (ACLR). Today, ‘anatomical’ techniques are used. They have replaced the earlier ‘transtibial’ techniques, which were unable to control the knee’s rotational stability.

What is the best type of graft?

Reconstruction of the anterior cruciate ligament requires the use of a graft, which is selected on a case-by-case basis depending on each patient’s age, height and weight. The choice is also influenced by the type of sport and the frequency and intensity with which it is practiced, as well as certain biomechanical characteristics of the joint.

The most commonly used grafts are:

  • Hamstring tendon: Its main advantage is reduced morbidity in the area from which the graft is taken, and the possibility of its regeneration. It is also aesthetically favourable, since the scar is smaller (approx. 25 mm) and is located on the anterointernal part of the knee. As for disadvantages, the main issue is the time it takes for the tendon to attach to the bone (10-12 weeks).
  • Patellar tendon: The greatest advantage is that the graft attaches faster (4-6 weeks), but in exchange, there can be greater anterior knee pain after surgery. It is also less aesthetically pleasing, since the graft is obtained by making an incision of 5-6 cm on the front part of the knee.
  • Quadriceps tendon: This is similar to the patellar tendon technique. The graft is obtained along with a bone fragment from the superior pole of the patella, but there is no bone fragment on the opposite end. The main advantages are rapid attachment to the femur and less anterior knee pain than is generated by patellar tendon grafting. The disadvantage is that it requires the same amount of time to attach to the tibia as the hamstring tendon does.

These are the main options in the case of primary surgery. Other tendon structures or allografts are usually reserved for revision or multiligamentary surgeries.

Which patients have a greater risk of re-tearing after an ACL reconstruction?

There is sufficient evidence to suggest that some patients have a greater rate of failure or re-tearing after reconstruction of the anterior cruciate ligament. They include:

  • Patients younger than 18
  • Athletes with a high level of pivoting in the knee
  • Hypermobile patients
  • Patients with a high degree of preoperative rotational instability
  • Patients who undergo revision surgeries

For patients who have one or more of these characteristics, anterolateral tenodesis is usually performed in order to reduce residual instability and/or the rate of re-tearing.

When should surgery be performed?

The ideal moment is when the joint is no longer inflamed, mobility has been completely regained and the pain has subsided. To help make this happen, the patient is prescribed a series of rehabilitation guidelines to follow before the operation, such as performing exercises to strengthen muscles or undergoing cryotherapy. Keep in mind that doing a good job before the operation will optimise postoperative results.

What is the postoperative period like, and how long is the recovery time?

The patient tends to remain hospitalised until the day after the surgery. A brace is used to protect the knee for the first two weeks and to help keep it extended at night.

During the first days and weeks, pain control (through cryotherapy and specific medication) and muscle activation (through isometrics exercises) are prioritised. Mobility is progressively regained, adding muscle-building exercises according to each patient’s level of tolerance.

At this stage, it is essential to have a personalised rehabilitation process, which requires a coordinated effort between the surgeon and the physiotherapist.

All patients who undergo ACL surgery should resume practicing sports gradually, following a ‘return to play’ programme in accordance with each patient’s specific athletic activity.

During this part of the process, working together with the rehabilitator is vital in order to carry out a programme that involves functional activities, improvement and correction of athletic movements and muscle strengthening. This will not only allow the patient to achieve a high level of satisfaction when it comes to resuming sports, but also decrease their likelihood of suffering a new injury.


The training programmes of EQUILAE, a leader in the scientific community

Since 2004, Equilae has been welcoming doctors and consultants in trauma and orthopaedics from all around the world to join us as fellows. Thanks to our teaching efforts, we have not only successfully trained many specialists, but have grown our unit thanks to the exchange of professional experience and knowledge. Our network of contacts has expanded, and we’ve established many valuable friendships that continue to grow stronger.

We continuously improve upon and fine-tune our training programme, which has earned us wide recognition as a teaching centre for scientific studies from the AEA (Spanish Association of Arthroscopy), ESSKA (European Society of Sports Traumatology, Knee Surgery & Arthroscopy) and ISAKOS (International Society of Arthroscopy, Knee Surgery & Orthopaedic Sports Medicine).

Since it was established, the programme has continued to improve with the incorporation of a range of educational activities. At present, we have a monthly arthroscopic simulation practice, a semi-annual cadaver lab and two monthly clinical sessions. In addition, our fellows are given the opportunity to participate in important national and international conferences and various scientific events. The team also takes part in additional care activities (3-5 weekly consultations) and surgical activities (we carry out over 600 surgeries a year).

Due to the programme’s high demand from doctors all around the world, we have set a limit on the number of fellows we accept at a time. By doing so, we have created an organised work structure that guarantees an environment conducive to the highest level of learning where our participants can take full advantage of the programme, paving the way for the team’s research and care activities.

Additionally, since 2003, Equilae has been sponsoring one paid fellow to join the programme each year. This role gives the chosen fellow the opportunity to deepen their involvement with and commitment to the team, and to take on tasks of greater responsibility. In other words, the fellow plays a crucial role in the team’s structure.

At Equilae, we understand that sharing knowledge and experience is one of the best ways to grow. To this day, 83 orthopaedic surgeons, hailing from 28 different countries and 5 continents, have taken part in the fellowship programme.

As is often the case, we believe that it’s best for the fellows themselves to share first-hand accounts of their experiences. In the following video, Dr Simone Perelli from Italy recounts his experience as a fellow from July 2017 to June 2018.

The fellowship programme is one of our top priorities, and we are constantly working to improve it. At Equilae our doors are always open.

Thank you to all those who have made it possible.


The Spanish National Congress of Arthroscopy and Knee Surgery awards Equilae for its scientific work

At Equilae, we continue to maintain our commitment and passion for scientific work. This has served us well, earning us recognition from the scientific community over the last few years. During this time, national and international journals have published a great number of articles featuring our research and written by various members of our unit.

Thanks to constant effort in our scientific work, our team, led by Dr Juan Carlos Monllau, has received two prestigious awards. They were presented to us at the 6th AEA-SEROD Joint Congress, held from the 24th to the 26th of May in Zaragoza.

Equilae was awarded the prize for Best Article Published in a Leading International Journal for our recent work on lateral meniscal transplantation, published in the American scientific journal Arthroscopy and entitled ‘Capsulodesis Versus Bone Trough Technique in Lateral Meniscal Allograft Transplantation: Graft Extrusion and Functional Results’. Dr Àngel Masferrer presented it in the team’s name.

In addition, we received a second award for Best Surgical Video for our video entitled ‘Reconstruction of both cruciate ligaments with parental grafts in patients with open physes’, which was presented by Dr Pablo Gelber.

Just as they did at the ESSKA congress in Glasgow several days before, our team members played a prominent role at the congress, participating in various presentations, scientific discussions and live surgeries.

In Zaragoza, the great professionals that make up our unit once again made us proud, both of them and of the new recognition that our scientific and surgical work in the field of knee surgery and arthroscopy has received. We will keep working to remain a leader in this area. Thank you to everyone who made this possible!


Equilae publishes an improvement to the meniscal transplant technique


It is widely known that there is a relationship between the amount of meniscal tissue resected and the appearance of degenerative changes in the knee as the years go by. Because of this, current techniques tend to be relatively conservative—if the tear allows for it—with the goal of repairing the damaged meniscal tissue or replacing the previously meniscectomised tissue.

In 2001, Equilae performed the first allogenic meniscal transplant. This technique aimed to reduce the symptoms of a patient who had been meniscectomised in the past (a condition that was called ‘post-meniscectomy syndrome’).

Since then, more than 200 meniscal transplants have been performed, with improvements continuously made over time.

In recent years, Equilae has incorporated capsulodesis into the lateral meniscal transplant technique, in order to avoid or reduce the extrusion of the transplanted meniscus. This is achieved by passing the sutures through the articular capsule and inserting them into two tunnels through the tibia.

Regarding this technique, we would like to share the article that we recently published in the journal Arthroscopy, which constitutes a level II study. It presents the results obtained after comparing the first series of meniscal transplants with bone plugs to the current series, in which the capsulodesis technique was incorporated into the replacement surgery.

You will find that in the group of patients who underwent capsulodesis, there was a lesser degree of meniscal extrusion, along with similar improvements in functionality and pain relief.

Capsulodesis is a reliable and replicable technique that does not require the use of implants.

We hope that you find it of interest.

You can access the full article here.

The technique in question can also be viewed at the following link.


Fernando Belasteguín and his experience with sporting injuries

Fernando ‘Bela’ Belasteguín, the world’s best padel player for 16 years running, tells us about his experience with sporting injuries.

At Equilae we have a lot in common with the Argentine athlete; in addition to him being one of our patients, we’re brought together by the pursuit of excellence and our passion for what we do. We were eager to talk to him about sporting injuries, because we knew he could offer a very interesting perspective.

During the interview, ‘Bela’ tackled some interesting issues: attitudes when facing an injury and the importance of common sense in decision-making, pre- and post-operation procedures, criteria for selecting a surgeon and the importance of rehabilitation.

He’s a shining example of a great athlete and an even greater person. Enjoy!



Equilae develops a new technique to prevent knee infections

Today we would like to share the preventative approach that Equilae takes towards knee surgery infections, as well as the development of a new technique that has allowed us to completely eliminate the risk of infection after anterior cruciate ligament reconstruction.

The newspaper La Vanguardia covered this story:

A new technique eliminates infections related to knee ligament injuries

Degenerative knee injuries (arthrosis or joint wear and tear) can greatly affect quality of life by causing pain and getting in the way of everyday activities. On the other hand, knee ligament injuries (of which ACL injuries are the most well known) make regular athletic activity impossible, which also negatively impacts active individuals.

At Equilae, when we operate on a patient due to a degenerative injury or a knee ligament injury, the goal is to restore their quality of life and athletic ability. Patient satisfaction is our mission.

However, complications can occur that slow down this return to normalcy, such as post-surgical infections. Recovery can be made even more difficult if an infection is not treated properly. Below, we first explain prosthetic infections (occurring after total knee replacement surgery) and then ligament surgery infections (occurring after anterior cruciate ligament reconstruction, ACLR).


Infection after total knee replacement surgery

The average rate of knee replacement surgery infection in Europe is about 2.5-3%. Equilae has managed to reduce this rate to 1.5%. This has been achieved through the implementation of various measures:

  • Bacterial decolonisation prior to surgery: through the utilisation of antiseptic agents in the days leading up to surgery, it is possible to reduce the possibility of bacteria being present on the patient’s skin, which can lead to infection.
  • Optimisation of antibiotic prophylaxis: when a prosthesis is implanted, antibiotics are always administered before performing the surgery. This results in a reduced risk of infection. In addition, at Equilae this prophylaxis is adapted to the risk factors of each patient (obesity, previous antibiotic treatments, rheumatic diseases, etc.), according to the most recent studies on the subject.
  • Use of antibiotic-loaded cement: biological cements are used in order to anchor the knee prosthesis to the bone (both the femur and the tibia). These cements can be loaded with antibiotics, making them an effective method according to the prosthesis records of Scandinavian countries.

What happens if the knee replacement prosthesis becomes infected despite these measures?

Fortunately, the Equilae team is accustomed to managing prosthetic infections; we belong to prestigious European organisations dedicated to studying this subject (e.g. ESSKA and the Pro-Implant Foundation).

The most important part of managing an infection after total knee replacement surgery is the diagnosis, since these infections often only cause pain, and are not accompanied by the symptoms that indicate infection to patients and many professionals: pus, fever, etc. This lack of knowledge can have serious consequences, because if the infection is not diagnosed, it will not be properly treated. Therefore, when presented with a patient who has been experiencing pain after a total knee replacement, it is crucial to rule out the possibility that this pain is due to a prosthetic infection. This type of infection, which only presents itself as pain, is known as a low-grade infection, since the bacteria are able to infiltrate the prosthesis and form a biofilm that prevents antibiotics from working. For this reason, if a total knee replacement prosthetic infection is diagnosed, it is necessary to perform surgery while antibiotics are being administered.


Infections after anterior cruciate ligament reconstruction (ACLR)

This type of infection is fairly less common than that of total knee prosthesis, but it is equally important. European records indicate a rate of infection between 1 and 2%. In recent years, Equilae has managed to reduce the rate of ACLR infections to 0. This has been achieved through the implementation of a technique developed together with Australian researchers. The technique consists of immersing the ACL plasty (the new ligament that will be implanted to replace the broken ligament) in a vancomycin solution. This practice has been endorsed by several scientific studies and has allowed Equilae to join the prestigious ACL Study Group, as well as to participate in scientific research conventions with renowned hospitals like Berlin’s Charité. These partnerships have enhanced our knowledge of the origin, prevention and treatment of ACLR infections.


Ultimately, it is a matter of employing measures aimed at reducing the risk of infection, and optimising treatment in order to improve the patient’s quality of life.



The evolution of meniscal surgery: from 1980 to today

As members of Equilae, it is always a pleasure to have Dr. Monllau share his experience with us. This time, he’s discussing the evolution of meniscal surgery from the early 1980s to today. We hope you find it as interesting as we do.

For many years, complete meniscectomy was the treatment of choice for a meniscal tear. This technique provided good clinical results in the short term, but these results deteriorated over time.

In the 1940s, Dr. Fairbank described the appearance of radiographic arthritic changes after a complete meniscectomy. Over the years, a relationship has been shown to exist between the quantity of meniscal tissue resected, chondral damage and subsequent degenerative changes appearing in the meniscectomized compartment.

Meniscectomies have grown increasingly conservative, mainly since the advent of arthroscopy in the early 1960s.

Towards the end of the 1980s, the concept of suture-based meniscal repair arose.  Despite this, and for various reasons (the vascularization of the meniscus, progression time, the type of injury, etc.), not all meniscal tears should or can be sutured. It some cases it is still necessary to perform a partial meniscectomy.

During the 1990s, in an effort to prevent the deterioration of the joint after a meniscectomy, meniscal transplant appeared on the scene, through implants in cases with partial meniscal defects, or allografts or “donor meniscus” for complete meniscal defects.

Dr. Monllau and his team have made numerous relevant scientific contributions to the field of meniscal replacement over the last 10 years. To date, more than 150 collagen and polyurethane implants and around 200 meniscal transplants have been performed at Equilae.

Over the years, the technique used by the team for meniscal transplants has evolved (initially, the transplant focused only on sutures, later with bone plugs and most recently using capsulodesis) in order to obtain better results in terms of pain reduction, increased quality of life, the prevention of wear of the joint and the optimization of extrusion of the transplanted tissue.

When can a meniscal transplant be performed?

The most common surgical indication for a meniscal transplant is the emergence of post-meniscectomy syndrome. That is, the appearance of pain, discomfort and/or effusion in a patient who has had a meniscectomy and is at an early age for the use of a prosthesis.  Also, the joint must show limited articular degeneration, integrity of the ligaments and correct alignment of the extremity.

What postoperative care should follow?

Postoperative care will be adapted to each patient based on the surgical procedures that have been carried out.

In general, the patient will remain at rest and with the knee extended for the first two weeks. Then, they will progressively increase weight-bearing using crutches until the sixth week.  The joint’s range of motion will increase, allowing for flexion greater than 90° after the sixth week.

The concept of joint preservation

After 16 years of experience and more than 200 patients operated on at Equilae, it can be concluded that after meniscal transplant surgery, patients attain a decrease in pain and improved quality of life, changing the natural history of a degenerative knee and delaying possible prosthetic surgery.