Prof. Dr. med. Sven Shafizadeh is a recognized specialist in knee surgery and sports traumatology, practicing at the Sportklinik 360° at the Sana Dreifaltigkeits Hospital in Cologne. His extensive expertise and many years of experience have made him a leading authority in treating knee joint injuries and disorders. He is especially known for his skills in reconstructive joint surgery and sports injuries.
His focus lies in treating complex knee injuries and conditions. These include anterior and posterior cruciate ligament reconstructions, treatment of knee dislocations and multiligament injuries, as well as specialized procedures involving the patella, such as trochleoplasty and MPFL reconstruction. Prof. Dr. Shafizadeh also performs corrective osteotomies for leg misalignments, tendon injuries such as ruptures of the biceps, hamstrings, quadriceps, and patellar tendons, and surgeries for pediatric knee injuries. His expertise also covers complex cases and revisions of failed surgeries, as well as advanced cartilage cell transplantation and meniscus surgery techniques.
At the Sportklinik 360° locations in Cologne and Leverkusen, Prof. Dr. med. Sven Shafizadeh and his team offer state-of-the-art high-performance medicine. The philosophy of Sportklinik 360° and the Med 360° clinic network is based on providing highly specialized care, ensuring that patients always feel they are in the best hands. This is achieved through a close integration of outpatient and inpatient care, which regularly draws attention in the medical community through pilot projects and innovations.
Prof. Dr. med. Sven Shafizadeh has over 20 years of experience as a specialist in surgery, orthopedics, and trauma surgery. His expertise is in demand both nationally and internationally. He has published numerous scientific articles in international journals and is a regular speaker at conferences. He also teaches at the University of Witten/Herdecke, reflecting his deep integration in both academic and clinical medicine. Close collaboration with radiology and orthopedic experts ensures precise diagnostics and the rapid development of individualized treatment plans.
Leg axis misalignments are common among the population. Studies and estimates suggest that about 20 to 30 percent of adults in Germany are affected by some form of leg axis deviation. This includes both knock-knees (valgus alignment) and bowlegs (varus alignment). These numbers may be even higher in children and adolescents, as many misalignments may improve or worsen during growth and development.
The editorial team of the Leading Medicine Guide had the opportunity to discuss this topic in detail with Prof. Dr. med. Shafizadeh.
Leg axis misalignments, such as knock-knees (genu valgum) and bowlegs (genu varum), are common orthopedic deviations that affect the biomechanics of the lower extremities and can lead to significant health issues. These misalignments result from uneven joint loading and may have both genetic and acquired causes. Accurate diagnostics are crucial to determine the severity and causes of the misalignment and to initiate targeted therapeutic measures. Modern treatment options—ranging from conservative approaches to surgical interventions—offer promising solutions to correct leg alignment and improve joint health in the long term. In this context, it is important to understand the mechanisms of development, diagnostic methods, and current therapeutic options to make informed decisions regarding treatment of leg axis deviations.
Leg axis deviations, also known as leg axis abnormalities, result from a multifactorial interaction.
“We often see two main groups of patients. On the one hand, there are children and adolescents with congenital, genetically determined misalignments in the form of knock-knees or bowlegs. This group is particularly interesting medically because growth-guiding procedures can be performed at an early stage. During the growth phase, such deformities can often be corrected with minimal surgical intervention to achieve leg axis alignment and prevent future problems. This is a preventive measure aimed at avoiding functional issues and joint damage—similar approaches are effective for foot deformities. This is important because foot deformities can also lead to knee and hip issues over time. The second important group includes patients who have had bone fractures—of the thigh, lower leg, or ankle, for example. If the fracture doesn’t heal properly, a variety of misalignments can develop, including knock-knees, bowlegs, rotational deformities (deviation from the normal rotational axis of the leg), or issues involving the upper or lower leg. These are the two main patient groups we treat. Misalignments due to obesity are actually quite rare,” explains Prof. Dr. Shafizadeh at the beginning of our conversation.
Leg axis misalignments cause uneven joint loading, increasing the risk of developing osteoarthritis in the knees and hips. With knock-knees, the outer part of the knee is subjected to more stress, while with bowlegs, the inner part is more affected—both scenarios can lead to premature cartilage wear. Early diagnostics and preventive measures such as physical therapy, orthopedic aids, and healthy lifestyle habits are essential for optimizing joint loading. In severe cases, surgical correction may be necessary.
Early diagnosis and intervention play a crucial role in preventing the progression of leg axis misalignments and associated joint problems.
“Diagnostic procedures depend significantly on the type of patient we're seeing. Children with misalignments usually don’t have symptoms. They are brought in because parents or teachers have noticed abnormalities. If such deviations are present during growth and differ from the norm, a consultation with a pediatric orthopedic specialist is recommended. Only a trained expert can determine whether immediate intervention is needed, if observation is sufficient, or if treatment is necessary. For adult patients, it’s a different situation—they usually seek help because of symptoms. Here, diagnostics are focused on identifying the underlying causes. These symptoms could stem from cartilage or meniscus damage or ligament injuries. In the past, diagnostic evaluations focused solely on one joint. Today, we take a much more comprehensive approach. Patients are assessed functionally, not just joint by joint. Functional assessments of adjacent joints and the overall leg axis are now integral to the diagnostic process. If there are joint issues—whether in the knee, hip, or foot—and leg axis deviations are a factor, patients undergo targeted evaluations to understand the role of the misalignment. Individual assessment of joint issues and their causes is very important today. Only then can we determine whether immediate treatment is needed or whether we have time to develop a treatment plan. Diagnostics today are far more advanced than in the past. We can now much more precisely assess the severity of a leg axis deviation. The overall management of these conditions has also improved significantly,” says Prof. Dr. Shafizadeh, offering further insights into diagnostic procedures:
“A detailed analysis of symptoms is essential—diagnostics in orthopedics and trauma surgery follow a somewhat different approach. The specific symptom profile comes first—we need to know if symptoms are triggered by everyday activities or occupational or athletic exertion. A thorough functional and clinical examination is standard to assess issues during daily life or sports. What kind of pain is occurring and how does it progress over time? Is it linked to an injury or to a newly introduced activity? Are there any underlying conditions contributing to the problem? We try to understand all these interrelationships. Depending on the findings, we initiate further targeted diagnostics if necessary. The second step involves a clinical examination, which is essential. Misalignments such as knock-knees, bowlegs, or rotational deformities can often be evaluated even without imaging. However, if the condition warrants clarification, conventional X-ray techniques are used—these can capture the entire leg. Modern X-ray methods allow for precise measurements of misalignments with minimal radiation exposure and help determine whether immediate treatment is needed. This can prevent the need for further imaging in some cases. If advanced imaging is necessary, we may use MRI or CT, depending on the symptoms and findings, to allow for individualized analysis. MRIs and CT scans may be required in addition to conventional X-rays, especially when the entire leg needs to be imaged to measure the leg axis. Torsional analysis, especially for rotational deformities, may also be necessary. There are now more complex procedures like low-dose CT (very low radiation), which is a new trend and particularly useful for rotational abnormalities. The choice of diagnostic tool depends on the specific issue. For example, we see many patients with patellar instability—where the kneecap dislocates repeatedly—who often have knock-knees or a rotational deformity in the femur or tibia. As long as that rotation problem isn’t corrected, the instability can’t be fully resolved. In such cases, a simple X-ray is definitely not enough.”
X-rays provide a clear visualization of bone structures and help identify leg axis misalignments such as knock-knees (valgus alignment) or bowlegs (varus alignment). X-ray images can be taken from both frontal and lateral perspectives to assess bone alignment and accurately measure deformities. They are particularly useful for preoperative planning and monitoring postoperative progress.
Computed Tomography (CT) offers a more detailed three-dimensional view of bone structures compared to standard X-rays. CT scans are especially valuable when a precise analysis of bone architecture and joint surfaces is required. They aid in diagnosing complex deformities and capturing the exact anatomy of a joint, which is crucial for planning surgical interventions.
Magnetic Resonance Imaging (MRI) provides detailed images of soft tissues, including muscles, tendons, ligaments, and cartilage. While MRI offers less detailed views of bone itself, it is particularly helpful for evaluating accompanying soft tissue injuries or conditions commonly associated with leg axis misalignments. MRI can also help assess cartilage condition and detect early-stage damage.
Three-dimensional (3D) X-ray imaging or digital 3D analysis enables a comprehensive assessment of leg alignment and joint mechanics. These modern techniques allow for precise three-dimensional analysis of the leg axis and joint orientation, which is especially advantageous for planning complex corrective surgeries. They provide detailed imaging of bone structure and alignment across multiple planes and help determine the exact corrective requirements for personalized therapy.
Leg axis misalignments can lead to significant biomechanical and functional impairments, increasing the risk of secondary joint damage and chronic pain. When joint degeneration progresses or substantial loss of function occurs—especially if misalignment is accompanied by osteoarthritis or other structural damage—surgical intervention is considered.
“It’s very important to emphasize that not every leg axis misalignment requires surgery. The key is to carefully analyze the root cause of the symptoms. Some patients may have bone misalignments that cause no pain, while others may suffer from functional misalignments due to muscular imbalances. In those cases, targeted physical therapy focused on strength and coordination can be sufficient. A clinical exam alone may be enough, and imaging like X-rays can often be avoided,” Prof. Dr. Shafizadeh explains, and adds regarding conservative options: “If the cause is functional and related to muscular issues, therapeutic exercises—whether self-guided or supervised by a physiotherapist—can sometimes partially or even fully resolve the symptoms. However, in cases of complex misalignments that affect the cartilage, ligaments, or menisci, only bony corrections can effectively relieve joint stress and become necessary.”
Prof. Dr. Shafizadeh therefore recommends thoroughly evaluating all non-surgical treatment options before deciding on surgical correction of leg axis misalignments. If conservative approaches such as physiotherapy, orthopedic insoles, and medication do not provide lasting relief or improve function, then an osteotomy may be indicated.
Leg axis misalignments can lead to significant biomechanical and functional impairments, increasing the risk of secondary joint damage and chronic pain. When joint degeneration progresses or significant functional loss occurs—especially when accompanied by osteoarthritis or other structural damage—surgical intervention becomes a consideration.
“The goal of a bony correction is to reduce pain, improve stability, or slow the progression of osteoarthritis. One of the most common leg axis corrections is performed in cases of osteoarthritis combined with bowlegs. This is one of the most frequent conditions we see here. Realigning the leg not only reduces pain but also aims to delay the need for joint replacement due to arthritis. In many cases, a prosthesis can be avoided or postponed by ten years or more. Corrections for knock-knees or rotational deformities are often done in patients with patellar instability or trochlear dysplasia. Depending on the location of the deformity, the correction may be performed on the femur or tibia. Due to our specialization, we also treat many patients who have experienced multiple ACL tears despite undergoing ligament reconstruction. Often, the underlying cause is a malalignment of the tibial plateau. In these cases, we perform corrective osteotomies to change the slope of the tibial plateau and prevent further ACL injuries. These procedures are very effective, and we have substantial experience, especially with athletes,” Prof. Dr. Shafizadeh explains.
Regardless of the type and location of the deformity, the most common surgical technique for correcting leg axis misalignments is osteotomy. During an osteotomy, the affected bone is surgically cut and repositioned to correct the misalignment. These procedures are typically performed using minimally invasive techniques and under radiologic guidance to ensure precise alignment. In a valgus osteotomy, for example, the bone is realigned to correct bowlegs. Conversely, a varus osteotomy is used to treat knock-knees. Both procedures aim to improve biomechanical joint loading and slow the progression of joint degeneration.
Prof. Dr. Shafizadeh offers reassurance and encouragement regarding surgical interventions: “In the past 10–15 years, there have been incredible advancements in surgical techniques and implant technology. As a result, most procedures can now be performed safely and efficiently using minimally invasive methods. These innovations have significantly reduced complication rates—an especially important factor for younger, active patients. A simple correction of knock-knees or bowlegs now takes only 30 to 45 minutes. More complex cases may take up to 1.5 hours. Thanks to modern techniques, patients recover much faster. In the past, they would have had to stay in bed for six weeks. Today, they are mobilized with crutches the day after surgery, and typically stop using them after 4 to 6 weeks. Full recovery in daily life usually takes 8 to 12 weeks, depending on the type of osteotomy performed. That may seem like a long time, but it’s a worthwhile investment in the long-term health of the leg and knee. These operations are generally easy to plan, so time off work can be coordinated. In children and adolescents, however, we shouldn't wait too long due to growth considerations. In our clinic, we mostly treat adults dealing with wear-related issues or complications from previous injuries.”
Technological advances in minimally invasive surgical techniques and the development of modern, stable implants have significantly contributed to adapting rehabilitation protocols. These improvements in implant materials and surgical methods have enhanced biocompatibility and durability. As a result, recovery times have shortened and prognoses have improved substantially. Additionally, a better understanding of biomechanics has led to more individualized therapy approaches, combining surgical correction with targeted physiotherapy and personalized treatment plans to ensure optimal outcomes.
“If treatment is delayed too long, it’s like driving a car with a misaligned axle or damaged shock absorber. Taking that car on long-distance trips or even onto a racetrack will clearly increase wear and tear. It’s the same with the human body. For someone with severe knock-knees, for example, the risk of developing arthritis is significantly higher compared to someone with properly aligned legs,” notes Prof. Dr. Shafizadeh.
At the Sportklinik 360° in the Sana Dreifaltigkeits Hospital Cologne, around 2,500 surgeries for leg axis misalignments are performed each year.
The Sportklinik 360° at the Sana Dreifaltigkeits Hospital in Cologne is one of the largest centers in Germany specializing in the full range of knee surgery, and especially in correcting leg axis misalignments. As a certified joint center by the German Knee Society (DKG) and the Society for Arthroscopy and Joint Surgery (AGA), patients at the clinic are treated exclusively by experienced specialists under the leadership of Prof. Dr. Shafizadeh to ensure optimal outcomes.
“We also strive to prevent joint injuries and conditions through better preventive care and to develop new treatment options through research. Specialization currently plays a critical role in ensuring successful patient outcomes. Our physicians are highly skilled experts who can manage the full range of conditions. Personally, I would like to see more emphasis on preventive measures. We need to reduce injuries! Regarding personalized implants and instruments, I believe there is still much progress to be made. And I am confident that in the future, we will be able to replace cartilage and tissue even more effectively,” concludes Prof. Dr. Shafizadeh as we wrap up our conversation.
Thank you very much, Prof. Dr. Shafizadeh, for the valuable insights into treatment options for leg axis misalignments!
