As the largest joint in our body, the knee has to withstand a great deal. After all, our entire body weight rests on the complex structure of the knee, where numerous ligaments, tendons and bones come together. To be precise, the knee has to bear around four times our body weight – and if we stumble, it can even be eight times that! To enable us to walk, run and turn properly, the individual components of the knee must work together like clockwork. If one component fails or is affected, it hurts immediately – and our mobility is restricted. Knee specialist Dr Alfred Tylla explains exactly what happens in this expert interview. As Senior Consultant in the Knee Department at Rummelsburg Hospital, Dr Tylla has dedicated himself entirely to the knee joint – and is jointly responsible for the outstanding reputation that the Knee Center enjoys far beyond the region. In fact, in 2019 it became the first specialist clinic in the entire Nuremberg metropolitan region to be certified by the German Knee Society.
To ensure that everything in the knee runs like clockwork, in the truest sense of the word, there needs to be effective coordination between the patella, cruciate ligaments, lateral ligaments, medial ligaments and the meniscus, which acts as a shock absorber, cushioning and dampening all the movements we make. Unfortunately, however, meniscus injuries are quite common. While athletes are often affected – for instance, by making an incorrect twisting movement while playing tennis – the meniscus is also a delicate structure in everyday life.
“The meniscus works like a shock absorber in a car,” Dr Tylla begins our conversation and explains: “If it is damaged, this can lead to severe pain, impair mobility and cause the joint to swell. If left untreated, the damage will eventually lead to osteoarthritis, which cannot be cured, only managed.”
Osteoarthritis is a degenerative condition in which the joint cartilage wears away progressively. The wear and tear of the cartilage is accelerated by a lack of exercise, as it is only through the use of the joint that the synovial fluid necessary for smooth movement is pumped through the cartilage. If the synovial fluid is lacking, bone eventually rubs against bone.
Nowadays, sports are also becoming increasingly extreme. Faster, further, higher is the motto for many athletes. “Unfortunately, people repeatedly underestimate just how much strain is placed on their knees. Those who go skiing in winter have often not really trained at all throughout the year. The muscles around the knee aren’t as strong as they need to be for skiing. People often simply don’t prepare adequately, and then it doesn’t take much for a careless movement to damage the meniscus, causing a tear, or even a complete rupture. “As a rule, the meniscus is injured during a rapid twisting movement, because during such movements it gets caught between the joint surfaces and can tear or even rupture completely,” explains Dr Tylla, outlining the problem of overloading.
Each knee has a meniscus, a crescent-shaped piece of cartilage situated between the joint surfaces of the thigh bone (femur) and the shin bone (tibia). It is divided into an outer and an inner meniscus. Menisci consist of ninety per cent collagen fibers, which can absorb shear and tensile forces. Significant tensile stress is required, for example, during squats.
Meniscus damage does not always require surgical treatment
“If someone comes to me with severe knee pain, the first step is to determine whether something acute has happened, such as a fall. An MRI scan will ultimately provide a clear picture. Conservative treatment involves icing the knee, resting it and elevating it. This is followed by muscle strengthening. Stable thigh muscles are extremely important for the meniscus, so these are strengthened with targeted exercises,” says Dr Tylla, describing the option of conservative treatment.
Age also plays a major role in deciding whether surgery is necessary or not. “For younger people who are still very active, it usually makes sense to suture the meniscus. This can generally be done arthroscopically. To do this, I make two small incisions on the inner and outer sides of the knee joint to then suture the meniscus back together. The suturing techniques used here are well-established, and the whole procedure takes between half an hour and an hour. Only tiny scars remain, and the patient is back on their feet more quickly due to the short wound healing time,” says Dr Tylla, describing the operation.
Like cartilage, the meniscus has no nerve fibers, so a meniscus tear or rupture does not in itself cause pain. The pain occurs when torn pieces become trapped in the joint, thereby stretching the joint capsule.
If the meniscus injury occurred some time ago and the patient only begins to suffer from restricted movement and pain at a later stage, then only the frayed or torn parts of the meniscus are removed during surgery. Only the absolute minimum is removed, as otherwise the risk of developing osteoarthritis later on increases. “I would like to emphasise that, before any surgical procedure, it is carefully assessed whether the operation is actually necessary and makes sense. Conservative treatment is always considered first,” explains Dr Tylla.
“Of course, there are also implants that can be used, but this is usually only done for young patients. This is because the bureaucratic hurdles in Germany are very high. Some companies no longer offer their implant systems due to expired CE certification,” explains the knee specialist, highlighting the difficulties with implants.
Everyone can take preventive measures to strengthen their knees
“Most people are too gentle on their knees. Many knee operations could be avoided if people exercised more and took part in sport. After all, it is only through movement that blood circulation is stimulated. Many of my patients suffer from functional instability of the knee and are sometimes no longer able to perform simple squats. Of course, one shouldn’t overdo it with sport or overestimate one’s abilities. Incorrect strain – that is, when exercises are not performed correctly and with proper form – is the result, which in turn damages the knee. In such cases, you should consult a sports coach at the outset, for example if you’ve decided to join a gym. “But healthy knee muscles generally improve stability and prevent injuries,” advises Dr Tylla to his patients.
Problems caused by bow legs and knock-knees
Knees are also quickly affected if there is a bow-legged or knock-kneed misalignment. This is often caused by genetic predisposition. “However, such a misalignment can also result from trauma, for instance if a leg injury has not healed properly,” explains Dr Tylla. A misalignment of the legs places a particularly high strain on the knee.
“With bow legs, there is constant inward pressure on the meniscus, causing it to wear out more quickly. With knock-knees, the opposite is true. Here, the pressure is on the outer side of the meniscus. Bow legs are more common than knock-knees and can be corrected through a minimally invasive operation known as a corrective osteotomy. The entire axis of the leg can be surgically altered in this procedure, which is a minimally invasive operation lasting no longer than 45 minutes. Unlike in the past, the legs are no longer broken during surgical straightening but are bent instead, which allows for faster healing. The straightened leg is fixed in place with a titanium plate. The aim is for bone tissue to regrow. The patient is then usually fit again after four to six weeks and can put their full weight on the leg. After the operation, the patient is given a mobilization splint and must be prepared to only bear partial weight on the leg for the next three to four weeks. “After around six weeks, a further three weeks of rehabilitation or physiotherapy should follow, and nine weeks after the procedure, the patient will be able to walk well again,” explains Dr Tylla.
Orthoses are used in the conservative treatment of bow legs or knock-knees
“The orthoses then push the legs into the desired position. This takes place over a period of around ten to twelve weeks. A simulation is then used to check whether the treatment has been successful or not. If the patient benefits from this form of therapy, realigning the leg is also a sensible treatment option,” says Dr Tylla. The chances of correcting the leg alignment using orthoses naturally decrease the more pronounced the leg deformity is. A certain amount of patience is also required, of course. However, these options should be exhausted before deciding on surgical correction.
The high standard of care in knee surgery at the certified Knee Center at Rummelsburg Hospital is evident in sports orthopedics, traumatology and osteotomy. Anyone undergoing knee surgery here can be assured that at the Rummelsburg Clinic for Trauma Surgery, the minimum requirements are not merely met but significantly exceeded, with at least six hundred complex procedures of high quality performed annually.
“For the future, I hope we can succeed in improving cartilage regeneration so that surgery can be avoided with certainty. Healing with stem cells should also be optimized,” explains Dr Tylla at the end of our conversation.
Many thanks to Dr Tylla for this informative conversation! You can contact our expert directly via his profile page on the Leading Medicine Guide.
