Arthroscopic surgery

Thanks to the constant development of arthroscopic instruments, arthroscopy has long since established itself as the gold standard in the treatment of numerous injuries as well as degenerative damage to the knee joint. It can be operated on in such a minimally invasive way, using only small accesses via a high-resolution screen. Most damage to the menisci and cruciate ligaments can be treated arthroscopically, cartilage damage can be addressed, and troublesome scarring after injury or previous surgery as well as entrapment of mucosal folds can be removed. In the case of complex injuries, open surgery may also be necessary in addition to arthroscopy in order to either treat extra articular ligaments such as the collateral ligaments or tendons or to perform cartilage and bone grafts. Even bone fractures can sometimes be set and stabilized with arthroscopic assistance.

Meniscus surgery

Meniscus tears can occur both as a result of acute injuries in sports accidents or as late damage in chronic instabilities (e.g. after cruciate ligament injuries) even years after cruciate ligament surgery. Acute traumatic meniscus tears often occur in childhood after sports or recreational accidents and are often associated with other injuries to the ligaments or cartilage surfaces. Since the menisci have a variety of tasks in the distribution of pressure in the knee joint, the protection of the articular cartilage, as well as in the stabilization of the joint, the most important goal of meniscal surgery is to preserve the meniscus. Fresh tears in the blood supplied parts (red-red or white-red zone) can often be treated with sutures and have a good prognosis with healing rates of up to 80% with the correct indication and technique, but it is particularly important that concomitant injuries such as cruciate ligament tears or cartilage injuries are also treated because they influence each other positively. Depending on the shape of the tear, a variety of suture methods are available today, all of which should be mastered by experienced knee surgeons to enable a suture strategy adapted to the shape of the tear. Both classic menniscus sutures with cannulas (outside-in or inside-out sutures) and prefabricated suture loops from various manufacturers (all-inside suture systems) are used. In special cases where the entire meniscus root (root-tear) is torn, refixation to the tibia bone with sutures passed through the bone may also be necessary. In the case of injuries to the medial meniscus ramp (ramp lesion), which regularly occur in the context of injuries to the anterior cruciate ligament, special ramp sutures are also sometimes required, which are performed via an additional access to the posterior part of the joint under arthroscopic view.
In some cases, however, either due to the configuration of the tear or the localization of the tear in tissue that is not perfused, suturing may not be technically possible or promising. In these cases, the unstable portion can then be removed arthroscopically (partial meniscus resection), leaving a reduced stable residual meniscus. Often, however, a combination with removal of the non-perfused parts and suture in the red zone is possible (hybrid treatment) so that more meniscus tissue can be preserved.
In the case of severe destruction of a meniscus in an otherwise largely healthy knee, a meniscus transplantation can also be a good solution in rare cases, since in the case of complete meniscus loss in active and young patients, a rapid development of knee joint arthrosis is to be expected. Donor menisci from various suppliers are available for this purpose and can be implanted using either an arthroscopic or an open technique.
Degenerative meniscal tears often develop over a long period of time due to excess pressure in the affected compartment or overload in combination with a decrease in the tensile strength of the tissue. In some cases, residual (micro) instability following previous burn injuries also plays a role. Degenerative tears often become symptomatic after minor trauma or without trauma and may be accompanied by persistent joint effusions. Because of the poorer healing prospects of these tears, suturing is only possible in exceptional cases after thorough freshening of the rupture. In many cases, a partial removal is indicated, whereby care is taken to preserve as much meniscal tissue as possible and, above all, not to damage the annular fibers, since otherwise the meniscus loses its function due to the loss of tension.
Chronic overloading of a compartment can also lead to subluxation of the meniscus from the joint space. In these cases, the holding apparatus of the meniscus is often chronically overloaded. In these cases, stabilization of the meniscus with suture anchors inserted at the tibial plateau may also be necessary. In addition, correction of the leg axis with realignment osteotomy is often indicated in such cases to prevent recurrence.

Ligament stabilization incl. revision surgery

In the course of sports accidents as well as work and traffic accidents, injuries to the ligaments of the knee joint occur due to various trauma patterns. The capsule-ligament apparatus of the knee joint has a very complex structure and, in addition to static stabilizers, also has dynamic stabilizers in the form of tendons. Individual ligaments can be injured (most commonly the anterior cruciate ligament), especially in the context of sports accidents involving rotational and hyperextension injuries. However, complex injury patterns involving multiple ligaments as well as important capsular structures, the menisci, and the cartilaginous surfaces can also occur. Depending on the injury pattern, a treatment concept must be developed in each individual case. This can range from conservative treatment with a knee orthosis in combination with physiotherapy for simple injuries, for example to the medial collateral ligament, to complex surgery with refixation or reinforcement of ligaments or ligament replacement surgery with various tendon grafts.

Rupture of the anterior cruciate ligament

Rupture of the anterior cruciate ligament is a relatively common sports injury that occurs frequently in many ball sports with opposing contact, such as soccer and handball, but also in skiing, snowboarding, martial arts, fun sports and gymnastics. The most common mechanisms of injury are hyperextension of the knee joint or a twisting motion with the knee bent over the standing lower leg. If there are no concomitant injuries to mensici or cartilage as well as other ligaments, a non-surgical therapy can be attempted in some cases, depending on the form of the tear as well as the activity level. In this case, a brace is applied and a partial load is applied for a few weeks, followed by rehabilitation under physiotherapeutic supervision. If, following rehabilitation, there is still instability in daily life or during sports with giving way symptoms, arthroscopic replacement of the insufficient cruciate ligament with a tendon graft (quadriceps tendon, semitendinosus tendon, allograft) should be performed. This is selected on a patient-specific basis depending on several factors (leg axis, concomitant injuries, etc.).
In the case of fresh ACL ruptures, the ligament can be reattached to its origin on the thigh within a few weeks during arthroscopy in some forms of rupture in which the anterior cruciate ligament is still well preserved. In adults, the ligament can also be reinforced and splinted with a textile band (ligament bracing). In this way, the patient’s own cruciate ligament can often be preserved. However, in case of failure of the refixation, cruciate ligament replacement surgery can be performed without any problems.
In children and adolescents, the anterior cruciate ligament can also tear bony at the tibial plateau. In the case of dislocated tears, the fragment should be arthroscopically reduced to its bed and fixed with dissolvable sutures to ensure good function of the anterior cruciate ligament. Any associated injuries can be treated in the same operation.

Rupture of the posterior cruciate ligament

The posterior cruciate ligament runs behind a synovial covering and is more strongly developed than the anterior cruciate ligament and ruptures much less frequently. Due to better blood circulation, the healing potential is also significantly greater with non-operative therapy, so that conservative therapy with orthosis and physiotherapy is usually carried out for the time being in the case of fresh ruptures without concomitant injuries. If there are concomitant injuries to the menisci or multiligamentous injuries, as in the case of a previous knee dislocation, it is often useful to perform a suture of the posterior cruciate ligament combined with augmentation (ligament bracing) to allow sufficient healing of the posterior cruciate ligament.
In the case of an obsolete ACL rupture or insufficient healing with posterior knee joint instability, there is an indication for ACL reconstruction. This is performed analogously to ACL reconstruction arthroscopically with tendon grafts or allografts. Often, in the case of chronic posterior instability, intensive physiotherapy must be performed prior to surgery in order to eliminate a fixed deformity that would prevent the success of reconstruction.

Revision surgery

Even after cruciate ligament reconstruction has been performed, insufficiency of the graft can occur even after years, either due to a new trauma or (partial) misplacement of the ligament, with a renewed feeling of instability and giving way attacks. If compensation by retraining the thigh muscles cannot eliminate the subjective instability, revision surgery is often required to restore knee joint stability with a new graft. In some cases, when the drill channels are widened or the placement of the former graft is not completely anatomical, the revision must even be performed in two stages. In the first operation, the widened or incorrectly placed canal is refreshed and filled in, and then, in the second operation about 3-4 months later, favorable conditions are created.

Patellar stabilization after patellar luxation

Patellar luxation occurs more frequently in adolescents aged 12-16 years for the first time. In some cases, trauma may be the cause (e.g. a fall on the knee or a kick directly against the kneecap). However, it is not uncommon for the patella not to be optimally guided in its sliding bearing on the thigh due to its constitution, and dislocation can occur even in the case of slight trauma as well as twisting of the knee during sports or in the case of severe instability, even without trauma. In the context of a patellar luxation, the retaining apparatus of the patella is usually torn to various degrees, and cartilage injuries to the patella or the outer part of the femoral condyle are also common. In the presence of bone-cartilage tears, surgical treatment is usually required acutely. Here, the torn osteochondral fragment can be refixed with small absorbable pins or headless screws. In the case of very small fragments or if they originate from non-weight-bearing articular surfaces, they can be removed arthroscopically. In the same session, the torn medial retinaculum as well as the medial patellofemoral ligament (MPFL) can be sutured arthroscopically (modified Yamamoto suture) to prevent further patellar dislocation. In simple cases without flake fractures, a nonoperative approach is usually chosen after the initial dislocation. After swelling of the knee joint has subsided, a patella-centering orthosis is applied for 6 weeks and physiotherapy with muscle building is performed. In case of a second dislocation, a detailed analysis of the predisposing factors should be performed. Depending on the pathology, surgical treatment can then include reconstruction of the capsular ligamentous apparatus with tendon grafts (MPFL plasty with gracilis or quadriceps tendon) as well as correction of the leg axis with a varicose osteotomy on the upper or lower leg and, in the case of a torsion defect, torsion correction. In the case of a very shallow gliding groove in the context of severe trochlear dysplasia, a deepening of the gliding groove (trochleaplasty) may also be necessary in some cases. It is not uncommon for several measures to have to be combined to ensure good function of the patellofemoral joint.

Tendon injuries at the knee joint

Tendon ruptures at the knee joint mostly affect the quadriceps tendon or the patellar tendon. These strong tendons can rupture during a fall due to sudden maximum contraction of the very strong quadriceps muscle. This immediately causes significant instability in the knee joint and prevents walking. In some cases, the tendons may be damaged by chronic medication (especially cortisone preparations or lipid-lowering drugs, as well as antibiotics in some cases) and tear in the event of minor trauma. Due to the loss of function, surgical therapy is almost always necessary. In this case, the continuity of the tendon is restored with various suture techniques adapted to the rupture. This can be followed by mobilization with partial weight-bearing using a knee orthosis. In chronic ruptures with strong retraction of the stumps, where direct suturing is no longer possible, the tendon must be reconstructed by local tissue plasty (reversal plasty) or by tendon grafts. Tears of the knee flexors (hamstring tendons) can also be treated conservatively in some cases, but dislocated tears of the biceps tendon at the head of the fibula are often refixed using anchors or transosseous sutures.

Fracture treatment

Fractures in the knee joint can involve the distal femur, the patella or the proximal tibia. Because these portions are joint-forming, fracture displacement is generally associated with intra-articular step formation and, if left untreated, can rapidly promote the development of osteoarthritis. Completely undisplaced fractures can also be treated conservatively in individual cases with plaster or orthosis and unloading. However, fine repositioning and stabilization is often required to achieve exercise stability and promote rehabilitation. Depending on fracture location and fracture type, a variety of surgical techniques and specialized implants are available to stabilize fracture components in an anatomic position. In some cases, joint fractures can also be reduced under arthroscopic view and then minimally invasively fixed with plates or screws. Subsequently, exercise treatment under physiotherapeutic guidance is required to achieve good mobility and accelerate rehabilitation.

Cartilage therapy

Lesions of the articular cartilage of the knee joint can affect all joint surfaces. In the course of knee torsions in recreational or sports accidents, the cartilage can be injured by crushing or shearing. It is not uncommon for the subchondral bone to be torn off as well (so-called osteochondral shear fracture / flake fracture). If the diagnosis is made early, the torn piece of cartilage can often be reduced to its bed arthroscopically or in an open technique and fixed in a stable manner with the aid of special absorbable nails or sutures so that it can heal again. In the case of fragments not suitable for refixation or chronic cartilage damage, various surgical options are available depending on the size and depth of the damage. For small and shallow defects, so-called bone marrow stimulating techniques can be used with good success. Here, after removal of the unstable cartilage parts in the base of the defect, the bone is superficially milled off and drilled with special instruments to release the bone marrow. The stem cells and growth factors contained in the bone marrow can then transform into new replacement cartilage in the defect. This effect can be enhanced by inserting a hyaluronic acid or collagen matrix into the defect to locally bind the leaked blood as well as the stem cells and growth factors and give the cells a space to develop (matrix augmented chondrogenesis, AMIC method). Even larger defects (from about 2 to 6 cm2) often exceed their own regeneration potential and show better results after autologous cartilage cell transplantation. For this, however, an additional arthroscopy is necessary to remove the chondrocytes from a non-loaded zone. The chondrocytes are then propagated and allowed to mature under sterile conditions in a special laboratory within approximately 4 weeks. After harvesting the cells, they are then placed in a collagen or hyaluronic acid matrix and reimplanted in a 2nd operation (matrix augmented chondrocyte implantation – MACT). If there is also a bone defect, this can be filled with bone cylinders from the iliac crest in a gap-free and mechanically stable manner as part of the 2nd operation. For good success in surgical cartilage therapy, however, all concomitant pathologies must also be addressed. In particular, ligamentous instabilities after cruciate and collateral ligament ruptures as well as mechanical overload in the case of axial malalignment must be eliminated by appropriate procedures during the first or second operation.

Leg axis corrections

The importance of the mechanical leg axis in the development of joint osteoarthritis has been known for a long time. Before the widening of joint prostheses, correction of the mechanical leg axis was the most important surgical tool for the treatment of osteoarthritis of the knee and ankle. In recent years, the importance of axis correction in the treatment of chronic instability of the knee joint has also increased significantly, so that this procedure is experiencing a renaissance, also thanks to new modern techniques, instruments and implants. In cases of unicompartmental osteoarthritis or chronic ligamentous instability and corresponding malalignment, corrective osteotomy can alter the load on the joint and both slow the progression of osteoarthritis and improve joint stability. In order to analyze the malposition as well as the overload, whole-leg still images and, in some cases, slice images must be taken (MRI and CT). This is followed by a detailed analysis and planning of the correction. First of all, the joint angles must be used to determine in which bone (femur, tibia) the deviation is present and whether an additive, a subtractive or a torsional correction is required. In complex cases, different corrections must also be combined with each other and a correct load restored. During the operation, the correction is then made with millimeter precision based on the planning and the result is secured with a plate. Nowadays, modern plate fixators are available with which early full weight-bearing is usually possible after 4 weeks and which allow a quick return to everyday life. Compared to a (partial) prosthetic replacement, the patient’s own joint including proprioception can be preserved and often a good sports ability can be achieved. All necessary accompanying procedures such as meniscus surgery or ligament reconstruction can be performed arthroscopically in advance of the conversion osteotomy. The relief achieved allows cartilage damage to regenerate and reconstructed ligaments to be protected. Torsional corrections can also be used very effectively for patellar instability.

Joint-preserving arthrosis surgery

In advanced localized osteoarthritis, in addition to thinning of the cartilage, there are often bony attachments at the joint margins that can sometimes cause entrapment symptoms. Detached cartilage clods can form free joint bodies that can also become painfully jammed. In addition, there are unstable cartilage or meniscus parts. In addition, there are often painful inflammatory changes of the synovial membrane (synovitis) with joint effusions and restricted movement. In addition to consistent physiotherapy and anti-inflammatory and analgesic medication, arthroscopic surgery with smoothing of unstable cartilage, removal of pinching bone spurs and free joint bodies, and removal of disturbing mucosal villi (synovectomy) can lead to significant relief of symptoms. Following an arthroscopy, in the case of mild to moderate arthrosis, an injection therapy with autologous blood concentrate or, in the case of advanced arthrosis, with a combination preparation of highly cross-linked hyaluronic acid and cortisone can help to keep the joint irritation-free and reduce pain over a long period of time.

Autologous blood therapy (PRP / ACP therapy)

In the case of incipient osteoarthritis, an increased destruction of chondrocytes (cartilage cells) occurs, often due to mechanical causes such as overloading in the case of axis defects or instability after ligament injuries or meniscus injuries. The dying cells lead to the release of several substances (mediators) that cause a more or less pronounced inflammatory reaction in the knee joint. This inflammation causes the synovium to produce more fluid, which leads to painful joint swelling and effusion. This persistent irritation sets in motion a spiral of exertional pain and swelling that is often difficult to break. This can also result in painful swelling in the back of the knee caused by a bulging Baker’s cyst. In addition to traditional decongestant measures such as cryotherapy, range-of-motion exercises, and anti-inflammatory and analgesic medications, the joint’s irritable state can be calmed by concentrated infiltrations of the patient’s own blood. Autologous conditioned plasma (ACP) therapy exploits the regenerative capabilities of blood plasma, as well as platelets and blood stem cells, to improve the joint environment and as well as relieve pain. During ACP therapy, 15 ml of blood is drawn from the patient’s arm vein in the doctor’s office using an innovative double syringe system. The blood, including the double syringe, is then processed in a special centrifuge. This concentrates its active ingredients – mainly platelets, growth factors, but also stem cells. This produces plasma enriched with active substances, which is then injected directly into the affected joint. Each treatment lasts between 15 and 30 minutes. After the injection, the patient can immediately resume everyday activities. For the best possible results, three to five treatments are necessary, each one week apart. ACP therapy is thus an absolutely natural, very safe and well-tolerated type of pain therapy. It can help with osteoarthritis, tendon injuries and sports injuries to get fit again faster, reduce pain and significantly accelerate healing.

Osteoarthritis therapy with highly cross-linked hyaluronic acid and corticoids

In advanced osteoarthritis with deep cartilage damage or larger cartilage defects (grade 3-4), pain therapy as well as the treatment of chronic effusions can be challenging. In this case, injection therapy with the combination preparation CINGAL® has often proven effective. It combines the immediate anti-inflammatory as well as analgesic effect of cortisone tramcinolone hexacetonide with the long-lasting efficacy of cross-linked hyaluronic acid with the highest active ingredient content – for proven rapid and long-lasting pain relief. In the doctor’s office, the injection is administered sterilely into the affected joint using a pre-filled syringe. In many cases, pain relief can be achieved over several months. Compared to other preparations with repeated (up to 5 weekly) injections, the risk of infection after injection is significantly lower.