Dr. Georg Brandl, MD is an experienced specialist in orthopedics, orthopedic surgery, and traumatology, with a particular focus on knee joint treatment. For over two decades, he has devoted himself to both conservative and surgical therapies for knee-related conditions and enjoys an excellent reputation as a specialist in joint-preserving knee surgery and knee endoprosthetics. Thanks to his comprehensive training and ongoing education, he ranks among the leading experts in this field.
A core element of his work is joint-preserving knee surgery. Whenever possible, Dr. Brandl opts for minimally invasive methods to preserve the natural function of the joint and avoid early use of prosthetics. If joint replacement is unavoidable, he offers the most advanced minimally invasive techniques for partial or total prostheses that speed up healing and allow for quicker restoration of mobility. Since 2015, Dr. Brandl has been the lead surgeon at a certified joint replacement center in Vienna and performs numerous complex operations each year.
His expertise is emphasized not only by his hands-on experience but also through active membership in national and international scientific societies. He regularly gives lectures, organizes surgical workshops, and is actively involved in medical research. Currently, Dr. Brandl serves as Senior Consultant in the 2nd Orthopedic Department at Herz-Jesu Hospital in Vienna, where he treats patients with musculoskeletal conditions and injuries. Additionally, he conducts comprehensive diagnostics and individualized consultations at his private practice.
Due to his high degree of specialization, Dr. Brandl now performs exclusively knee surgeries. However, the scope of treatment at the newly opening OrthoZentrum Döbling in Vienna (starting September 2025) will extend beyond the knee joint to include conditions of the hip, foot, shoulder, elbow, and spine. The facility also offers a complete rehabilitation process to ensure optimal outcomes.
He is a highly sought-after specialist for sports injuries, aiming to restore athletic performance with targeted treatment strategies. Dr. Brandl places great emphasis on patient-centered care tailored to each individual's needs and lifestyle. Close collaboration with specialists from other fields ensures comprehensive treatment that considers all relevant aspects of the patient’s medical history. His top priorities are to relieve pain, restore mobility, and achieve the best possible long-term quality of life for his patients.
The editorial team of the Leading Medicine Guide spoke with Dr. Brandl specifically about anterior cruciate ligament (ACL) tears—one of the most common knee injuries.
A tear of the anterior cruciate ligament (ACL) is among the most common and severe knee joint injuries, especially in sports that involve rapid changes of direction, sudden stops, or jumping. It poses a particular problem because the ACL plays a central role in stabilizing the knee and cannot heal on its own. A rupture often leads to joint instability and increases the risk of secondary damage such as meniscus injuries or early-onset osteoarthritis.
Estimates suggest that around 80,000 people in Germany alone suffer an ACL tear each year, with athletes and physically active individuals being at particularly high risk.
“The ACL most commonly tears in young, physically active individuals – particularly in stop-and-go sports such as soccer, basketball, or volleyball. These sports involve abrupt changes in direction, jumping, and landing, which place significant rotational forces on the knee. Especially dangerous are situations where the foot is fixed – for example, when cleats get caught in the turf – and the body rotates over the knee. These injuries often occur without any contact from an opponent. Skiing also carries a high risk: while the lower leg is stabilized by the ski boot, the ski may move in another direction, creating rotational forces that strain the ACL significantly. Interestingly, many ACL tears occur either at the beginning or end of the season – early due to insufficient preparation or overload, and later due to fatigue.
Well-trained muscles, especially along the leg axis, are therefore crucial. Those who prepare in time with targeted strength training – also with physiotherapeutic guidance – can significantly reduce their risk of injury. Choosing the right footwear also plays a role. In soccer shoes, for example, round studs are often preferable to elongated ones because they reduce the chance of getting caught in the ground, and thereby decrease rotational stress,“ Dr. Brandl explains at the beginning of our conversation, and continues:
“Another key component of prevention is so-called proprioceptive training – which improves balance and deep sensitivity. It enhances the body’s ability to recognize risky movements early and respond with muscular counteraction. And it’s not just athletes who are affected: everyday mishaps, such as tripping over a carpet edge, can also lead to ACL injuries. The underlying injury mechanism is often quite similar – and ultimately, it is often a combination of muscular control, preparation, and sheer coincidence that determines whether the ligament holds or not.
Relying solely on the quadriceps muscle to stabilize the knee is not enough, as multiple muscle groups work together to support the joint. In addition to the quadriceps at the front, the posterior muscles – particularly the hamstrings – are essential. They contribute significantly to dynamic stabilization of the knee, especially during quick movements or sudden changes in direction. Often underestimated are the calf muscles, which act from behind the knee and also play a stabilizing role. While biomechanical data in this area are still limited, clinical experience shows that they, too, contribute to knee health. Strong muscles – front, back, and below – provide protection and stability. A well-rounded training program can significantly reduce the risk of knee injuries.”
Treatment of an ACL tear can be either conservative or surgical, depending on various factors. Both approaches aim to restore knee function and athletic performance but differ significantly in execution and long-term effects.
“When a patient presents with symptoms indicative of an ACL injury, there’s usually a noticeable event – such as a sudden twisting motion accompanied by an audible ‘pop’ and subsequent swelling. However, that’s not always the case. Some ACL tears initially present with minimal symptoms, and the only complaint is a ‘strange feeling’ in the knee. The degree of bleeding into the joint and the acute state of the knee post-trauma are often decisive in diagnosis.
Modern imaging, especially with high-resolution MRI scanners (e.g., 3-Tesla), allows us to visualize even the smallest structures in detail. Still, the clinical stability tests remain essential. The Lachman test or anterior drawer test provides key insight into how unstable the knee really is – and therefore, whether surgery is necessary. Not every ACL tear automatically requires surgery. Partial tears, where ligament remnants remain attached to the femur, can sometimes be treated conservatively – provided the knee remains stable. Supportive measures include muscle-strengthening programs and biological therapies such as platelet-rich plasma (PRP) injections to stimulate the body’s own healing processes,” says Dr. Brandl, and adds:
“The situation is different in the case of a complete ACL rupture: here, conservative treatment is usually ineffective because the knee’s biomechanics are significantly altered. Over time, this can lead to secondary damage such as meniscus tears – studies show that the frequency of medial meniscus injuries increases significantly after just one year. While exceptions exist – such as patients who cycle exclusively or can compensate through excellent muscle control (‘copers’) – the risks often outweigh the benefits, especially for young, active individuals. In most cases, surgical stabilization is therefore recommended for complete ruptures. Conservative approaches are possible but rarely result in long-term knee stability.”
The Lachman test is a clinical method used to assess the integrity of the ACL. In this test, the slightly bent tibia is pulled forward while the thigh is held steady. If there is significantly more forward movement compared to the uninjured knee, it suggests an ACL tear. The Lachman test is considered a highly reliable diagnostic tool for this condition.
In ACL injuries, pain is not necessarily the primary issue – especially in the long term. Acute pain may occur right after the trauma, but it often subsides within one or two months or disappears entirely. The real problem lies in the instability of the knee joint.
Dr. Brandl explains: “This instability doesn’t present itself constantly but rather in unpredictable moments – like going down stairs, changing direction quickly, or even turning a corner. The knee may suddenly ‘give way.’ This unpredictability leads many patients to feel insecure. As a result, they often adopt avoidance behaviors, consciously restricting movements and activities to avoid triggering instability. Still, it's generally possible to manage daily life without crutches or braces – provided risky movements are consistently avoided.
Some patients choose this path, often for personal reasons against surgery. But every case must be assessed individually: ACL injuries often involve more than just the ligament itself. Supporting structures such as the medial collateral ligament are frequently affected too. These cases lead to multidimensional instability, which limits conservative treatment options. If the ACL is the only damaged structure, and the knee remains largely stable, conservative treatment may be considered. But in complex injury patterns, surgical intervention is usually the best course.”
There are various surgical techniques available for treating ACL tears, primarily differing in how the ligament is reconstructed. The goal is to restore the knee's stability and function so the patient can return to their normal activities.
“Surgery after an ACL tear is generally well planned – it doesn’t need to be performed immediately. It’s crucial first to assess any accompanying injuries. If there are significant meniscus or cartilage damages, timely surgery is often advisable to avoid further harm. In other cases – for example, with concurrent medial collateral ligament (MCL) injuries – we often start conservatively, using a brace for about six weeks to allow the MCL to heal (which it typically does without surgery) before proceeding with ACL reconstruction. The condition of the knee right after the trauma also plays an important role.
If the knee is swollen or irritated, we begin with physical therapy to calm it down. Surgery is performed only once the joint is no longer inflamed – planned and controlled to minimize the risk of scarring. Typically, we recommend surgery around three months after the injury, though it shouldn’t be delayed too long to avoid secondary damage,” Dr. Brandl explains.
There are multiple surgical options. In rare cases, when the ACL has torn near its femoral origin and remains otherwise intact, it can be reattached arthroscopically – often combined with an “internal brace,” a thin synthetic fiber to provide additional support.
“This method is especially suited to less athletically active patients and is very gentle. In most cases, however, a ligament replacement is necessary. This involves harvesting an autologous tendon – typically hamstring tendons (from the thigh) or the quadriceps tendon. The choice depends on the patient's age, sport, and occupational demands. The quadriceps tendon is increasingly used in young, active patients as it regenerates well and causes fewer issues at the donor site.
For high rotational stress (e.g., in soccer), the patellar tendon is a good choice due to its bone blocks, which promote strong integration. However, this method is often not ideal for those who frequently kneel for work (e.g., tradespeople). Another option is the use of donor tendons (allografts), especially for older patients or when faster recovery without a donor site is desired. However, these require longer healing times. The actual ACL reconstruction is now performed minimally invasively and entirely arthroscopically. Only a small skin incision – usually less than three centimeters – is needed to harvest the tendon.
This allows for rapid wound healing and minimal visible scarring. The choice of technique is always personalized, taking into account the patient's athletic goals, occupational strain, and overall physical condition,” notes Dr. Brandl, and continues:
“In many cases, ACL surgery is an outpatient procedure. If the patient can stay for another three to four hours post-op for monitoring, pain is usually well controlled. However, whether outpatient treatment is suitable also depends on any additional procedures performed. For instance, if lateral ligaments must also be repaired, the surgery becomes more complex, and outpatient care is less advisable. Typically, patients stay overnight for observation. This ensures proper pain management and early mobilization support, easing the transition into the initial rehabilitation phase.
Patients who don’t seek treatment or delay care after an ACL tear risk long-term consequences. If the ligament is unstable – and the patient even notices it in daily life – that already indicates a significant functional impairment. In such cases, the body often relies on secondary stabilizers – such as the medial meniscus – to compensate. But persistent instability leads to overloading these structures, particularly problematic for the medial meniscus. Studies show that after about a year, the risk of major meniscus damage increases significantly. The meniscus can detach from the joint capsule, resulting in irreparable tears – often caused by routine movements, without additional trauma. Cartilage damage may also develop over time. This doesn't happen suddenly, but gradually due to chronic joint instability.
While the link between ACL rupture and cartilage wear isn’t as clearly established as it is with the meniscus, the trend is evident: knees with long-term instability wear out faster. That’s precisely why surgical techniques have improved significantly over the last decade – they are now much less invasive and more successful than they were just a few decades ago. As a result, surgical treatment has lost much of its stigma and now offers a reliable, long-term solution, especially when compared to purely conservative treatments, which often lead to gradual secondary damage.”
Donor tendons are sourced from tissue banks, consist of collagen tissue, and are not recognized as “foreign” by the body. These grafts integrate well and have proven effective in clinical practice. Artificial ligaments, by contrast, have been tested over the years—such as the so-called LARS ligament—but often led to complications, especially inflammation in the bone and bone tunnel enlargement.
Dr. Brandl explains: “Due to these negative outcomes, purely synthetic ligaments have now disappeared from the market and are no longer in use. The only remaining application involves thin synthetic fibers used as supplemental support during the sensitive healing phase of biological grafts. This technique is known as the ‘internal brace.’ In this case, the biological ACL graft is stabilized by a fine synthetic thread, offering some protection particularly in the early stages of healing. However, the main graft remains fully biological. While this technique is promising, current scientific data is still insufficient to make a clear recommendation. It remains an additional option in select individual cases—but the primary graft should always be natural tissue.”
When a patient returns home after ACL surgery, the first week is clearly focused on reducing swelling, rest, and recovery from the operation. A typical early symptom is limited knee extension – in other words, difficulty fully straightening the leg.
Dr. Brandl shares his personal experience: “For me, achieving full knee extension during the first one to two weeks is the top priority—it’s essentially the most important aspect of early physical therapy. Patients can often manage this on their own, without immediate physiotherapy instruction. The key is to restore mobility as quickly and effectively as possible—particularly full extension. After about two weeks, formal rehabilitation can begin. At this point, I strongly advise patients to seek physiotherapy support or enroll in a structured rehab program.
Doing this alone is simply too challenging, and most patients are unsure—what’s allowed, which exercises are beneficial, what should still be avoided? Many underestimate what they’re already capable of, especially when it comes to mobility. Often it’s fear—of doing something wrong—that holds them back. That’s why I consider the connection to physiotherapy a critical part of treatment, and I collaborate closely with several trusted partners. If there are no major accompanying injuries and recovery is going well, patients can usually take their first steps without crutches after about two weeks.
Returning to full functionality in everyday life typically takes six to eight weeks. Of course, there are exceptions—I once had a patient who climbed the Großglockner (3798m) just three months after surgery—but that shouldn’t be the benchmark. Six to eight weeks is a solid general estimate. It also depends on the type of work: people with desk jobs can often return within a week, but for a full return to active daily life, more time is needed.”
An individualized follow-up plan with scheduled check-ups is essential to monitor the healing process. This allows for early detection of potential complications and gives patients confidence as they reintegrate into their normal routines.
“I also see my patients regularly for follow-up after surgery. Everyone receives a personalized recovery plan with specific appointment dates. The first check-up typically happens around ten days post-op, when stitches are removed. I assess the knee’s appearance and whether swelling has gone down. The second check-up is about four weeks later, to evaluate whether supportive devices like braces or crutches can be discontinued.
Another important follow-up takes place after three to four months. By this time, most functions are working well again, and many patients want to know what comes next—especially when it comes to returning to sports. For athletes resuming training, this appointment is critical. In most cases, we recommend resuming sports no earlier than six months post-op, as sports place unique demands on the knee. At this stage, an MRI can be helpful to assess graft integration and give patients confidence. The greatest risk lies in returning too early—many re-injuries occur precisely for this reason.
For occasional recreational athletes—like someone who skis once a year—clinical evaluation may be sufficient. But for active athletes, it’s different: they often feel fit again after six months, but the graft typically takes nine to twelve months to fully heal and become resilient. That’s why we usually schedule the MRI right before the six-month mark. A final check-up is typically planned one year after surgery, although not every patient attends. Still, it’s an integral part of the follow-up plan. When I do this final check-up, I take another close look at everything to ensure long-term success of the operation.”
As a long-standing member and faculty member of the AGA and its ACL Committee (AGA = largest German-speaking arthroscopy society), Dr. Brandl focuses primarily on sports-related knee surgeries. The surgeon’s experience plays a major role in outcomes. Graft harvesting is a critical component of surgery, and not every surgeon is equally familiar with all types of grafts. This is why a dedicated specialization in ACL surgery is especially important, as surgeons who operate on all joints often do not possess the same level of expertise in this specific field.
“Even though some colleagues specialize in sports medicine and arthroscopic procedures, ACL reconstruction often demands an even more specific skill set. For that reason, I advise patients to consult a dedicated knee surgeon, since the quality of the procedure is crucial to long-term success. A well-executed operation usually results in good outcomes, whereas complications can lead to lifelong consequences. Each year, I perform around 500 knee surgeries, including approximately 150 ACL reconstructions. Many of my patients come not only from the local area but also from more distant regions—such as Slovakia, Hungary, and Budapest. This demonstrates the international demand for specialized treatment.
Looking ahead, there is still room for improvement, particularly when it comes to graft integration. Biological factors play a key role in explaining why healing progresses better in some patients than in others. Continued research and innovation in the biological healing process will be a major focus. There’s also interest in identifying which rehabilitation strategies best support healing. While surgical techniques are now quite refined, attention is shifting more and more toward biological approaches to enhance graft incorporation. Although we already have a wealth of knowledge, there remains great potential for further advancement in this field,” Dr. Brandl concludes our conversation.
Thank you, Dr. Brandl, for this in-depth insight into the treatment of anterior cruciate ligament tears!
