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Background: Abnormal angular and torsional alignment of the lower extremities during growth are a common reason for consultation of a paediatrician or orthopaedist. There is often uncertainty about the pathological value of these abnormalities and the need for treatment, even among specialists. In the course of physiological growth and development processes, the axial and torsional alignment of the legs sometimes change considerably and in characteristic patterns., Diagnostics: The ability to assess whether abnormal angular or torsional alignments of the lower limb in the course of growth should still be regarded as normal or already as pathological, depending on age and gender, is essential for the treating physician and requires precise knowledge of the physiological development processes and the tolerable limits in all three spatial dimensions., Treatment: After careful explanation to the frequently concerned parents, a restrictive approach with observation of the spontaneous course of correction on the basis of regular clinical check-ups makes sense in the majority of cases. Pathological deviations from the physiological conditions are rare overall, can be idiopathic or of secondary origin and should be further clarified diagnostically using imaging procedures. As conservative measures are ineffective, pronounced angular and/or torsional deformities of the legs requiring treatment can only be corrected by surgical intervention, even in children and adolescents. The surgical treatment modalities available are varied and differ in terms of their invasiveness and complication profile, depending on the localization, type and severity of the deformity, as well as the age and possible concomitant diseases of the affected child or adolescent., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Primary bone tumors are rare but more frequently seen during childhood and with predilection for the distal femur and proximal tibia. Therapy of benign tumors-if indicated-includes surgical resection in most cases, whereas malignant bone tumors such as osteo- and Ewing's sarcomas are treated with chemotherapy, wide resection and/or radiation therapy (Ewing's sarcoma). The reconstruction of emerging bone defects is significantly influenced by surgeon-related preferences and tumor-associated factors, respectively. Double-barrel vascularized fibula grafts or extracorporeally irradiated autografts in combination with a free fibula transplant are preferred biological reconstruction techniques around the knee joint. In cases in which the knee joint cannot be preserved, reconstruction is performed using tumor endoprostheses, but potentially emerging leg length discrepancies after resection of a potent physis must be taken into account. In considerably young patients, rotationplasty might represent a viable option with promising functional results., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Objective: Reduction of increased reclination of the tibial plateau (posterior slope) to improve the anterior stability of the knee joint., Indications: Increased posterior reclination of the tibial plateau greater than 12° in combination with recurrent instability after anterior cruciate ligament (ACL) reconstruction., Contraindications: Hyperextension of more than 15° (relative)., Surgical Technique: Anterior skin incision approximately 8-10 cm above the tibial tuberosity. Insertion of two converging guidewires directly below the patellar tendon ending obliquely in the area of the posterior cruciate ligament (PCL) insertion. Control of the wire position with the image intensifier core. Oscillating saw osteotomy. Removal of the wedge and closure of the osteotomy. Osteosynthesis with interfragmentary screw and medial angle-stable plate., Postoperative Management: Partial load with 10-20 kg for 2 weeks, then step by step increase in load. Mobility: free., Results: To date we have operated on 36 patients with recurrent instability after ACL reconstruction (20 men, 16 women, average age 34.4 years) in the manner described in this article. In 25 cases, enlarged bone tunnels were filled with allogeneic bone at the same time. The posterior slope of the tibial plateau could be reduced from an average of 14.5° to 8.8°. In 28 cases another ACL reconstruction was performed after an interval of 4-12 months. The Lysholm score significantly increased from 76.3 points to 89.2 points., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Preserving both cruciate ligaments in knee prosthetics enables approximately physiological joint kinematics. In this way, faster rehabilitation and a higher return-to-sports rate can be achieved. Accordingly, there are considerations to preserve both cruciate ligaments by combining two partial prostheses in the case of symptomatic bicompartmental (BiCom) knee osteoarthritis., Methods: This article summarizes the literature on BiCom arthroplasty and describes our own experiences from 54 consecutive cases with robotic-assisted technology., Results: According to current data, BiCom arthroplasty shows good clinical results, without being able to demonstrate a clear advantage over conventional TKA. The revision risk is slightly increased in the short-term interval, which could be positively addressed with robotic-assistance. The disadvantages are the increased implant costs and the risk of subsequent osteoarthritis. Accordingly, patients who may potentially take advantage of this treatment must be critically selected., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Partial knee replacement has proven to be an effective therapy for advanced unicompartmental arthrosis of the knee. Despite continuous advancements in implants and surgical techniques over the past decades, the global preference for total knee arthroplasty still persists for historical reasons., Objectives: This report aims to illuminate advantages and disadvantages of partial knee replacement considering long-term results, the evolution of indication criteria over recent decades and new aspects in patient selection with potential improvements through emerging technologies., Material and Methods: The analysis involves the examination of long-term results from clinical studies and registry data, highlighting the risk factors for potential failures and their influence on the development of indication criteria., Results: Present-day long-term results demonstrate excellent prosthetic survival, aligning with outcomes from total knee arthroplasty. New perspectives for expanding indication criteria are discussed, including the possible application of partial knee replacement in cases of severe varus deformity > 15°, anterior cruciate ligament insufficiency, young active patients, anterior knee pain, and/or patellofemoral arthritis, as well as mild radiographic arthritis with degenerative medial meniscus root tear and meniscal extrusion., Discussion: Indication criteria have consistently expanded in recent years, taking into account modern insights, and the application of advanced technologies can enhance precision and minimize surgical errors. Furthermore, this report emphasizes that revision rates are not the sole criterion for success and underscores the necessity for a comprehensive examination of clinical results., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Posterolateral instability of the knee joint typically occurs with injuries to the posterolateral corner of the joint or with additional combined injuries involving the anterior and posterior cruciate ligaments. In addition to numerous, smaller anatomical structures, the most important are the lateral collateral ligament (LCL), the popliteus muscle with its tendon, and the popliteofibular ligament (PFL), which can usually be assessed using magnetic resonance imaging (MRI). On the contrary, small structures like the arcuate ligament and fabellofibular ligament cannot always be identified. However, they are also of lesser importance in the development of posterolateral rotational instability. Overlooked injuries to the posterolateral joint corner promote instability with the complication of inadequate ligament reconstruction and early onset posttraumatic osteoarthritis. Knowledge of MRI morphology of the anatomical structures involved, taking into account their biomechanical significance, is crucial to recognize and use the corresponding imaging findings., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Objective: A rotational osteotomy requires a complete cut of the bone in order to correct maltorsion. An additional correction of the frontal axis can be achieved via an oblique cut of the bone. The osteotomy with bone to bone contact is fixed with an angle stable plate., Indications: Symptoms such as anterior knee pain, inwardly pointing knee syndrome, lateral patellar subluxation or dislocation, lateral patellar hypercompression syndrome are a common indication for derivational osteotomy if clinically increased femoral internal rotation and radiologically increased femoral antetorsion is detected., Contraindications: Increased hip external rotation versus internal rotation, increased femoral torsion but no increased internal hip rotation, malcompliance, inability for partial weight bearing, risk of delayed union (nicotine abuse and obesity) as well as patellofemoral arthritis and systematic glucocorticoids, immunosuppressants are (relative) contra-indications., Surgical Technique: A lateral or optionally medial approach to the distal femur and exposure of the bone with Eva hooks for the osteotomy is done. The use of patient-specific cutting blocks accurately specify the planned extent of derotation and level of incision. A defined oblique cutting plane of the single-cut osteotomy and derotation will additionally correct/change frontal axis. An additional biplanar osteotomy with an anterior wedge increases intraoperative stability and generates a larger bone contact area for consolidation., Postoperative Management: With the use of an extra medullary fixation device partial weight bearing with 15-20 kg with crutches up to 6 weeks is required, but no restriction on knee movement is given., Results: The literature shows significantly improved patient satisfaction regarding patellofemoral stability and knee function. With the use of patient-specific cutting guides, high accuracy of the osteotomy and 3‑dimensional correction can be achieved, while delayed union rate is up to 10%., (© 2024. The Author(s).)

The posterolateral corner of the knee is composed of a multilayered complex of ligamentous, musculotendinous, and capsular structures, which interact in a synergistic stabilizing manner with the central structures, particularly the posterior cruciate ligament. Injuries of the posterolateral corner are generally accompanied by rupture of the posterior cruciate ligament. Depending on the injured structures, injuries of the posterolateral corner result in posterolateral rotational instability alone (Fanelli A) or with lateral instability (Fanelli B/C). For rotational instability alone, isolated popliteus bypass is an effective procedure; with concomitant lateral instability in flexion, additional stabilization of the lateral collateral ligament is required. Most of the various available techniques are described as open reconstruction procedures. In recent years, arthroscopic techniques for posterolateral reconstruction have also been successfully developed., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Objective: Patient-specific cutting guides (PSCG) are used in osteotomy near to the knee joint to simplify the operative technique, shorten the duration of surgery, reduce radiation exposure and to exactly realize the preoperative planning during surgery, especially when complex deformities are corrected simultaneously in multiple planes., Indications: The application of PSCG is in principle possible in all osteotomies near to the knee joint but is especially useful in multidimensional, complex osteotomy., Contraindications: No specific contraindications., Surgical Technique: After multidimensional 3D analysis and planning using a preoperative computed tomography (CT) protocol, a 3D-printed patient-specific cutting guide is produced. This PSCG is used during standard osteotomy near to the knee. Using this PSCG the guided sawcut and predrilling of the screw positions inside the bone for the screws of the planned angle stable osteotomy plate are performed. The amount of the deformity correction needed is "stored" in the PSCG and is converted to the bony geometry during placement of the screws in the predrilled holes through the plate after opening or closing the osteotomy. Apart from that, the surgical approach and technique are equivalent to the standard osteotomy types near to the knee., Postoperative Management: The application of PSCG in osteotomy near to the knee does not change the postoperative management of the specific osteotomy., Results: The use of patient-specific cutting guides leads to a higher accuracy in the implementation of the preoperative planning and the desired target axis is achieved with greater accuracy. Multidimensional complex corrections can also be exactly planned and implemented. In addition, the intraoperative radiation exposure for the operation team can possibly be reduced., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Magnet resonance imaging (MRI) offers a precise visualization of structural changes with high sensitivity and specificity. However, not all these soft tissue damages or bony lesions are clinically relevant or require treatment. Therefore, it is important to provide the radiologist with a specific clinical request when asking for an MRI examination of the knee. In this article, all important anatomical structures of the knee joint will be addressed with emphasis on the relevant questions for the radiologist. Based on the clinical examination, the MRI provides information about the damage of anatomical structures. This information is of utmost importance for therapeutic decision-making in order to allow an adequate and personalized treatment of patients., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Objective: Correction of deformities around the knee joint in the frontal and sagittal axis, torsion, length and translation., Indications: Complex deformities of the proximal tibia, and to a lesser extent of the distal femur, which cannot be treated with acute correction using plate or nail osteosynthesis., Contraindications: Nicotine abuse, soft tissue problems, lack of patient compliance., Surgical Technique: First, mounting of the proximal ring of the ring fixator strictly parallel to the joint line in 2 planes, fixation with 3 or 4 pins or wires. Then mounting of the distal ring, fixation also with 3 or 4 wires, connection of both rings with 6 struts (movement units with which the length can be adjusted). Then the fibula osteotomy is performed in the transition from the distal to the middle third, and finally the tibial osteoclasia is performed via a mini-incision as a drill hole chisel osteotomy in the CORA (center of rotation and angulation) of the malposition., Postoperative Management: Immediately postoperatively, the deformity is defined usimg computer software, the exact position and size of the ring and struts are entered, and a knee image is taken in 2 planes with X‑ray signal adapter (beacon) on the ring fixator to plan the continuous correction. Thereupon continuous correction of the deformity via daily rotation on the 6 struts, which is done by the patients themselves at home after the hospital stay. At the time of correction, pain-adapted partial weight-bearing with 20 kg up to half body weight. After completion of the correction, repeat X‑ray diagnosis and check whether the correction goal has been achieved. If necessary, reprogram a program for renewed continuous correction if residual deformity remains. When the correction goal is reached, X‑ray check. After 6 weeks, with bony consolidation, gradual loading. The treatment of the correction can either be carried out in the ring fixator (wearing time of 0.5-1 year not unusual) or secondarily via a change of procedure to plate osteosynthesis., Results: We report on 25 knee joint corrections in 23 patients (12 women and 11 men) using hexapods (Taylor spatial frame) during the period 2016-2023. One patient had a femoral and a tibial fixator at the same time; another patient had a triple fixator at the tibia. The mean age was 32 (6-73) years. 15 left and 10 right corrections were performed. 19 fixators had been applied tibial, 5 fixators femoral, and 1 fixator cross-jointly (for contracture). The indications were 6 congenital complex deformities, 10 posttraumatic complex deformities, 3 pseudarthroses after correction osteotomies, 2 patients with osteomyelitis, 1 knee contracture and 1 infection after fracture osteosynthesis with nails. The forms of correction performed were varizations and valgizations in frontal axis, extension and flexion in sagittal plane, torsional corrections, lengthening also after acute shortening (pseudarthrosis resection) and segmental transport. Acute shortening without lengthening was also treated with the fixator only until bone healing and a Masqualet procedure was bridged with it. The average duration of fixator wear was 144 (31-443) days. All patients were followed up until final metal removal. There were 19 change of procedure to another osteosynthesis procedure (18 plate osteosynthesis, 1 ESIN); 6 times the treatment in TSF (Taylor Spatial Frame) was performed until final bone healing., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

The anterior cruciate ligament (ACL) is essential for the stability of the knee joint and ACL tears are one of the most common sports injuries with a high incidence, especially in sports that require rotational movements and abrupt changes in direction. Injuries of the ACL are rarely isolated and are often accompanied by meniscal and other internal knee injuries, which increase the risk of osteoarthritis. The spectrum of ACL injuries includes strains, partial tears and complete tears. Magnetic resonance imaging (MRI) plays a pivotal role in the diagnostics as it can accurately depict not only the ACL but also accompanying injuries. Proton density and T2-weighted sequences are particularly suitable for evaluating the ACL, which is usually well visible and assessable in all planes. In addition to depicting fiber disruption as a direct sign and central diagnostic indicator of an ACL tear, there are numerous other direct and indirect signs of an ACL injury in MRI. These include abnormal fiber orientations, signal increases and an anterior subluxation of the tibia relative to the femur. The bone marrow edema patterns often associated with ACL tears are indicative of the underlying injury mechanism. The treatment of ACL tears can be conservative or surgical depending on various factors, such as the patient's activity level and the presence of accompanying injuries. The precise and comprehensive description of ACL injuries by radiology is crucial for optimal treatment planning. Anterolateral rotational instability (ALRI) of the knee joint characterizes a condition of excessive lateral and rotational mobility of the tibia in relation to the femur in the anterolateral knee region. This instability is primarily caused by a rupture of the ACL, with the anterolateral ligament (ALL) that was rediscovered about 10 years ago, also being attributed a role in stabilizing the knee. Although ALRI is primarily diagnosed through clinical examinations, MRI is indispensable for detecting injuries to the ACL, ALL, and other internal knee structures, which is essential for developing an optimal treatment strategy., (© 2024. The Author(s).)

Introduction: Postoperative follow-up after joint-preserving knee surgery involves conventional physiotherapy as well as other approaches and devices such as CPM and CAM splints, TENS devices, BFR exercise, prehabilitation, and digital health applications. The aim of this survey was to investigate current standards, trends and control methods in postoperative care to identify fields of concern and to compare them with the current literature., Material and Methods: We conducted a structured anonymous online survey of specialists in orthopaedics and trauma surgery listed by the German-speaking Society for Arthroscopy and Joint Surgery (AGA). The questionnaire included 36 closed-ended questions on the follow-up of joint-preserving surgery of the knee joint., Results: Questionnaires from 528 participants with long-term professional experience (86.6% with more than 10 years) were analysed. Standardised post-treatment schemes are used by 97.2% and their evidence is estimated to be high (59.1%) / very high (14.8%). Problems of rehabilitation are seen in 10-20% of cases by 87.3% (persistent muscular atrophy 30.9%). After reconstructive surgery, CPM splints (70.1%), CAM splints (42.1%), orthoses (85.0%) and TENS devices (40.0%) are prescribed. More potent approaches for the treatment of postoperative muscle deficits are desired by 89.4%. BFR exercise is known by 41.7% and is used regularly by 8%. Communication with treating physiotherapists is infrequent (written: 27.5%). Digital rehabilitation management would be supported by 83.3%; 22.7% are not aware of digital health applications. 87.9% of participants believe that prehabilitation can affect postoperative outcomes., Conclusion: Follow-up of knee joint-preserving surgeries is usually standardised and regularly reviewed for up-to-date evidence. The evidence for recommendations made is considered high. Orthoses are usually used after reconstructive surgery, persistent muscle atrophy is a major problem, BFR training is only known to a limited extent, and there is currently a lack of standardised training protocols. Communication with physiotherapists needs to be improved. Digital rehabilitation management is rarely used but would be supported by the majority of surgeons., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Navigation-assisted surgical procedures in orthopedics and trauma surgery have become increasingly widespread over the last 20 years. In addition to applications in spinal surgery, they are primarily available for knee and hip endoprosthetics. On the one hand, computer-assisted procedures have been increasingly expanded with robotic assistance systems in recent years, and on the other hand, so-called handheld navigation systems have been developed, which enable specialized use directly in the operating field at lower acquisition costs. The aim of this overview is to describe current handheld systems and to present the respective technical principles and the available scientific results. Three handheld systems for TKA use, two for THA use and one system to support pedicle screw placement on the spine are presented., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Knee arthroplasty is a demanding procedure that, when carried out appropriately, results in significant pain relief and patient satisfaction. The success of the operation is influenced by many factors. The most important ones describe the implant design, the orientation of the components and the ligament tension. The patellofemoral joint is often neglected as an important part of the operation. Initially, complications in the area of the patellofemoral joint do not appear to be devastating, but in many cases, they lead to significant consequences for the patient, along with severe pain and limited mobility. The most common complications arise from patellar maltracking. This often occurs due to misplacement of the tibial and femoral components and the altered shape of the patella. If the placement of the components with regard to patellar tracking is considered, bony and/or soft tissue addressing measures remain to further optimize the movement of the patella. The following manuscript is dedicated to discussing causes to avoid patellar maltracking and improve clinical outcomes., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

The aim of treatment of a ruptured anterior cruciate ligament (ACL) is the return of the patient to an acceptable level of activity without giving way phenomena as well as adequate treatment of prognostically relevant concomitant lesions. The treatment of acute ACL ruptures can be either early reconstruction or a primary physiotherapy with optional later reconstruction. Which path is taken depends on possible concomitant injuries that require early surgical intervention (e.g., repairable meniscal injury or distal rupture of the medial collateral ligament) and on patient-specific factors (age, level of activity). Isolated ruptures of the ACL can also be primarily treated without surgery. Then the injured knee joint should first be so far conditioned by rehabilitative measures that pain, swelling and posttraumatic restriction of movement are improved and neuromuscular training can be started. A screening test consisting of jumping tests, patient-reported outcome measures and the testing for giving way phenomena can be suitable to differentiate compensators (copers) from noncompensators (non-copers). Surgical reconstruction of the ACL should be recommended to non-compensators in the sense of participatory decision-making. Activity modification (adapter) can also be considered as a treatment strategy. If instability events (giving way) or secondary meniscal lesions occur during nonsurgical therapy, cruciate ligament reconstruction should be considered., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

A knee dislocation is a serious injury involving at least two of the four major ligamentous stabilizers of the knee. This injury results in multidirectional knee instability. In dislocation of the knee the popliteal artery and the peroneal nerve can also be damaged. Dislocations with vascular involvement are potentially threatening injuries of the lower extremities. The diagnosis of knee dislocation can be difficult due to a high rate of spontaneous reduction at the initial examination. Knee dislocations are rare and mainly occur in young men. They are mostly caused by high-energy trauma; however, they can also be caused by low-energy injuries. Obesity increases the risk of knee dislocations. The classification of a knee dislocation is based on the anatomical structures involved and the direction of dislocation. The acute treatment includes reduction and stabilization measures. Associated injuries, such as vascular, nerve, extensor mechanism and cartilage injuries as well as fractures and meniscal injuries can influence the treatment approach and the outcome. The definitive surgical treatment depends on the severity of the injury and can include ligament reconstruction or repair with bracing. The aftercare should be individually adapted with the aim to restore knee joint stability and function. Complications such as arthrofibrosis, peroneal nerve palsy, compartment syndrome, postoperative infection and recurrent instability can occur. In the long term, patients have an increased risk for the development of symptomatic osteoarthritis., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Primary arthroplasty for fractures of the femoral neck is a very common procedure and even the gold standard for the geriatric patient. In contrast, primary arthroplasty for perigenicular fractures is a rare event. On the other hand, it can be a therapeutic option, especially for geriatric patients with prior osteoarthritis or complex fractures and severe osteoporosis.The operative procedure can be complex and requires experience in primary and revision arthroplasty as well as suitable implants and good preoperative planning.There are case series reporting primary arthroplasty in a total of approximately 200 cases of both distal femoral and proximal tibial fractures. Complication rates are between 0 and 90% and mostly concern wound healing problems and infections. From a functional point of view, predominantly good results and a range of motion of 100° can be achieved.Primary arthroplasty can be a therapeutic option for selected cases of perigenicular fractures and gives good functional results. The most frequent complications are wound healing problems and infections., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Background: The subjective evaluation of the patient's state of health with the help of Patient-reported Outcome Measurements (PROMs) provides valuable information for assessing the treatment outcome and for treatment planning. However, the use of PROMs in the field of arthroplasty is not mandatory, so that there is a lack of standardised recording and interpretation. The present study aims to identify patients, who have not achieved the intended treatment goals with regard to pain, function and quality of life after total knee arthroplasty, more easily in the future on the basis of postoperative PROMs., Material and Methods: Data collection (for 3-month postoperative follow-up) included a standardised clinical follow-up (NU) and a questionnaire of different PROMs (Oxford Knee Score [OKS], OKS Pain Score [OKSS] and EndoCert Risk Score [ERS]). During the specialist follow-up examination, it was decided whether further medical therapy had to be initiated. Accordingly, patients were grouped into four post-treatment categories (NU not required/further diagnostics/new prescription/revision required)., Results: For individual scores and questions, there were significant differences between the respective groups of consequences resulting from the follow-up examination. The OKS, OKS Pain Score and the ERS are suitable for detecting thresholds to determine the need for a follow-up examination. The postoperative thresholds of the scores are 24 for the OKS total score, 52 for the OKS pain score and 4 for the ERS pain intensity score., Conclusion: In the initial three months after knee arthroplasty, certain PROMs are suitable for identifying patients for whom further diagnostics and therapy are indicated. In particular, the OKS and the pain intensity score of the ERS are suitable for detecting a potentially unfavourable development in rehabilitation after total knee arthroplasty., Competing Interests: K. Osmanski-Zenk wird über ein Drittmittelprojekt der EndoCert GmbH finanziert, die hundertprozentige Tochter der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie ist. W. Mittelmeier ist ehrenamtliches Mitglied der Zertifizierungskommission der EndoCert GmbH., (Thieme. All rights reserved.)

Background: Knee dislocation (KD) is a rare but severe injury of the knee joint, with a high rate of concomitant neurovascular injuries. The severity of the ligamentous injury, which is classified according to the Schenck classification, the mechanism of injury, concomitant injuries and individual factors determine the treatment strategy in KD., Treatment Strategy: Furthermore, a clear differentiation between high-velocity (HV) and low-velocity (LV) injuries is necessary. Generally, surgical treatment within 7-10 days should be aspired. Herein, the one-stage hybrid treatment using augmented ligament sutures (ligament bracing) in combination with primary ligament reconstruction (posterolateral and ACL) leads to very good functional results in the mid-term. Ultra-low-velocity (ULV) dislocations and those with concomitant peroneal lesions require a modified approach, due to a limited prognosis. During rehabilitation, the individual progress must be closely monitored and follow an early functional approach. In approximately 20% of all cases, early arthroscopic arthrolysis shows a high success rate., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Introduction: After reconstruction of the anterior cruciate ligament, the modification processes in the transplanted tendon tissue directly influence the biomechanical properties of the knee. The histopathological alterations in failed grafts have hardly been studied., Objective: Our study focused on examining the presence and extent of tendinosis (low or high grade) in the tendon tissue of failed anterior cruciate ligament reconstructions. We considered its relationship to the type of transplant, the symptoms, the arthroscopic appearance, the mode of trauma, and the timing of the failure., Materials and Methods: The tendon tissue of failed anterior cruciate ligament reconstructions in 30 patients was gathered during revision surgery and its histopathology was analysed for the occurrence of structural alterations. The classification of the tendinosis as low or high grade was semiquantitative based on five qualities. We used a standardised questionnaire to collect patient data and we used the Marburg Arthroscopy Score for the intraoperative evaluation of the graft., Results: We found histological vitality and, except for two samples, structural alterations consistent with tendinosis, predominantly high grade, in all failed anterior cruciate ligament grafts. No direct link could be proved between the degree of tendinosis and the type of graft used, the symptoms (except for instability) or the timing of the graft failure, the mode of trauma, or the arthroscopic appearance of the failed plasty. However, the accumulation of high-grade tendinosis in patients with hamstring tendons, subjective instability, and graft failure between 1 to 5 years postoperatively was noteworthy., Conclusion: Structural alterations consistent with tendinosis could be detected, with different expressions, in the vital tendon tissue of anterior cruciate ligament reconstructions. This indicates that the graft is subject to repetitive microtrauma. However, it is still unclear how tendinosis influences the failure of anterior cruciate ligament reconstructions., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Objective: The goal of osteotomy is either to restore pretraumatic anatomic conditions or to shift the load to less affected compartments., Indications: Indications for computer-assisted 3D analysis and the use of patient-specific osteotomy and reduction guides include "simple" deformities and, in particular, multidimensional complex (especially posttraumatic) deformities., Contraindications: General contraindications for performing a computed tomography (CT) scan or for an open approach for performing the surgery., Surgical Technique: Based on CT examinations of the affected and, if necessary, the contralateral healthy extremity as a healthy template (including hip, knee, and ankle joints), 3D computer models are generated, which are used for 3D analysis of the deformity as well as for calculation of the correction parameters. For the exact and simplified intraoperative implementation of the preoperative plan, individualized guides for the osteotomy and the reduction are produced by 3D printing., Postoperative Management: Partial weight-bearing from the first postoperative day. Increasing load after the first x‑ray control 6 weeks postoperatively. No limitation of the range of motion., Results: There are several studies that have analyzed the accuracy of the implementation of the planned correction for corrective osteotomies around the knee joint with the use of patient-specific instruments with promising results., (© 2023. The Author(s).)

Objective: Three-dimensional correction of the bony alignment in the frontal and sagittal plane of the proximal tibia; surgery is performed via an open- or closing-wedge osteotomy to improve ligament stability and reduce joint degeneration., Indications: Chronic anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) instability and ligament revision surgeries; subjective knee instability in patients who are ambitious athletes and people who do physical labor; moderate joint degeneration with meniscus and cartilage damage, post-traumatic deformities., Contraindications: Time pressure (immediate meniscus surgery, since planning and production of patient-specific tools is time-consuming), lack of compliance (need for partial weight bearing, crutches), excessive smoking, vascular pathologies., Surgical Technique: Planning based on computed tomography (CT) data, determination of the axis of rotation with open or closing wedge, or dome osteotomy; production of corresponding patient-specific cutting blocks. Surgery is performed using the known standard approaches for a high tibial osteotomy (HTO). Exact positioning of cutting guides on the exposed bone. Sawing and adjusting the correction using an osteotomy chisel so that the reduction guide can be attached. Fixation of the achieved correction with angle-stable plate fixator., Postoperative Management: Partial weight bearing based on the extent of the correction for 6 weeks, free range of motion if no additional ligamentous reconstruction was performed. Subsequent full weight bearing after X‑ray and, if necessary, CT control., Results: No general results can be presented, since the surgical procedure, the indication, and the patient group are extremely heterogeneous. Accuracy of the cutting blocks used has been presented in other studies and is given as 0.8° ± 1.5° in relation to the frontal axis. However, the intraoperative change in the correction and adaptation to the surgical site that is presented depends on the surgeon and can greatly influence the extent of correction in terms of accuracy in complex corrections., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

As an increasing number of younger patients are undergoing total knee replacement (TKR) surgery, many wish to participate in sport, but still expect that the implant will survive for a extended period. Most of the current literature shows that patients predominantly participate in low impact activities, both before and after surgery. A few studies show that with appropriate previous experience, high-impact sports are possible and might not result in increased implant failure rates. These include a decrease in point loads on the polyethylene by using more conform bearing surfaces, avoidance of varus component alignment to minimise stresses at the implant bone interface and avoiding patella resurfacing to facilitate activities in deep knee flexion.A TKR is no longer an absolute contraindication for higher impact activities such as golf, tennis and ski. What is more important than implant specific factors seem to be patient specific factors, including preoperative activity level, and preoperative sport skills.The current review paper reports on the current sport habits of TKR patients, analyses biomechanical loads on the knee during different sport activities and reports on implant selection and technical considerations for the active patient undergoing TKR., Competing Interests: Dr. Boettner ist Consultant für Smith & Nephew, Ortho Development und Depuy. Dr Boettner erhält Royalties von Ortho Development., (Thieme. All rights reserved.)

Osteoarthritis of the knee is one of the most important degenerative joint diseases in the clinical routine. The treatment of knee osteoarthritis is not only based on the stage, symptoms and duration of the joint disease, but also depends on the existing arthrosis pattern. In the case of unicompartmental arthrosis, damage typical for osteoarthritis is limited to just one joint compartment. Both the conservative and the surgical treatment of unicompartmental osteoarthritis of the knee have to respect the individual characteristics of the respective forms of osteoarthritis. In the context of this manuscript, the genesis, the diagnostics and the guideline-based stage-adapted conservative and operative treatment of unicompartmental osteoarthritis of the knee are addressed., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Several treatment options for chronic periprosthetic joint infections have been published in the current literature, with an on-going discussion to determine effective management algorithms., Objectives: To compare outcomes of the two-stage exchange procedure in revision TKA prior to and after implementation of the PRO-IMPLANT Foundation treatment algorithm. The primary endpoints were defined as (i) revisions during the interval time, (ii) duration of the interval time and (iii) successful PJI eradication., Material and Methods: Between 02/2013 and 09/2016, 122 patients were included in a single-centre cohort analysis. 55 patients were treated according to the previously used algorithm (K1) and 67 according to the PRO-IMPLANT Foundation algorithm (K2). A minimum follow-up period of 3 years was set as the inclusion criterion. Successful eradication of infection was defined in accordance with the consensus criteria by Diaz-Ledezma et al. RESULTS: Successful eradication was achieved in 42 (67%) patients in K1 and 47 (85.5%) in K2 (p ≤ 0.005). The mean interval time was 88 days (range 51 - 353) in K1 and 52 days (range 42 - 126) in K2 (p ≤ 0.005). In K1, a mean of 0.8 (range 0 - 6) revisions were necessary during the interval period compared with 0.5 (range 0 - 4) in K2 (p = 0.066)., Conclusion: Implementation of the PRO-IMPLANT treatment algorithm led to significant improvement in the outcome of periprosthetic joint infections. During mid-term follow-up, infection eradication was highly successful, with decreases in the interval time as well as the number of revisions., Competing Interests: Dr. med. Hinnerk Baecker receives payments as a speaker from Zimmer Biomet, P. Brehm, Infectopharm and Aesculap AG./Dr. med. Hinnerk Baecker erhält ein Honorar als Referent von Zimmer Biomet, P. Brehm, Infectopharm sowie Aesculap AG., (Thieme. All rights reserved.)

Background: Registry data provide valuable epidemiological insights that help to further improve process and outcome quality in patient care. The German Cartilage Registry (KnorpelRegister DGOU) was established in 2013 as an instrument for quality assurance after surgical cartilage regenerative procedures on hip, knee and ankle joints., Data Collection: Participation in the German Cartilage Registry is optional for hospitals and practices. Currently, more than 160 institutions in Germany, Austria and Switzerland participate in the data collection., Data Collected and Initial Findings: The implementation of PROMs ("patient related outcome measurement"), as well as the recording of surgery-related influencing factors, enable a differentiated scientific analysis and represent a key quality feature of the registry. Initial analyses of the registry data have already provided clinically relevant findings for immediate patient care. For example, patients who underwent focal cartilage therapy prior to ACT show a clinically relevant, significantly worse outcome than patients who underwent primary ACT. First conclusions could also be drawn regarding the relevance of concomitant cartilage therapy. For example, in patients with focal cartilage damage of the medial knee joint compartment, registry data indicate that leg axis correction is indicated even in cases of mild deviation of the mechanical leg axis., Conclusion: The data and findings obtained from the Cartilage Registry represent an important aspect of clinical care research and serve as a complement to well-designed, clinically prospective cohort studies, RCTs, and meta-analyses., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

A 48-year-old male patient presented with inner skin retraction after a sports accident involving the knee. In a multi-ligament injury it must be assumed that knee dislocation has occurred. Inner skin retraction after knee distortion can result from an intra-articular dislocation of the ruptured medial collateral ligament. Prompt reduction and exclusion of concomitant neurovascular injuries is thus obligatory. After surgical reconstruction of the medial collateral ligament, instability was no longer apparent 3 months postoperatively., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Acute and chronic cartilage injuries are often encountered in professional and recreational athletes. They can compromise the athlete's performance and career and are considered a potential risk factor for early joint degeneration., Objectives: Incidence of cartilage injury in athletes, understanding of cartilage composition, injury mechanism and suitable diagnostic imaging are summarized and established therapeutic procedures, postoperative imaging including detection of relevant complications and assessment of reasonable indications for follow-up examinations are described., Methods: Original research and review articles were analyzed., Results: Cartilage injury can mimic meniscal or ligamentous injury and cannot be ruled out by clinical examination alone. Magnetic resonance imaging (MRI) is the method of choice to (1) detect (sensitivity 87-93%, specificity 94-99%) and grade cartilage lesions to facilitate choice of therapy and (2) to exclude concomitant injuries that require treatment to improve the prognosis of the chosen cartilage therapy. Postoperatively MRI allows noninvasive assessment of the repaired cartilage tissue and is an appropriate method to detect therapeutically relevant complications., Conclusions: Knowledge of mechanisms and appearance of cartilage injuries, current cartilage repair techniques and their imaging is crucial for the medical care of athletes., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Nowadays, kinematic alignment is a widely used alignment philosophy in total knee arthroplasty. The concept of kinematic alignment respects the patient's individual prearthrotic anatomy and is based on the reconstruction of the femoral anatomy and thus the axes of motion of the knee joint. Only then the alignment of the tibial component is adapted to the femoral component. By means of this technique soft tissue balancing is reduced to a minimum. Due to the risk of excessive outlier alignment technical assistance or calipered techniques are recommended for precise implementation. This article attempts to provide an understanding of the fundamentals of kinematic alignment, and it focusses on how it differs from alternative alignment strategies and the way the philosophy is implemented in different surgical techniques., Competing Interests: Erklärung zu finanziellen Interessen Forschungsförderung erhalten: ja, von einer anderen Institution (Pharma- oder Medizintechnikfirma usw.); Honorar/geldwerten Vorteil für Referententätigkeit erhalten: ja, von einer anderen Institution (Pharma- oder Medizintechnikfirma usw.); Bezahlter Berater/interner Schulungsreferent/Gehaltsempfänger: ja, von einer anderen Institution (Pharma- oder Medizintechnikfirma usw.); Patent/Geschäftsanteile/Aktien (Autor/Partner, Ehepartner, Kinder) an im Bereich der Medizin aktiven Firma: nein; Patent/Geschäftsanteile/Aktien (Autor/Partner, Ehepartner, Kinder) an zu Sponsoren dieser Fortbildung bzw. durch die Fortbildung in ihren Geschäftsinteressen berührten Firma: nein Erklärung zu nichtfinanziellen Interessen Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

The Working Group of the German Orthopedic and Trauma Society (DGOU) on Tissue Regeneration has published recommendations on the indication of different surgical approaches for treatment of full-thickness cartilage defects in the knee joint in 2004, 2013 and 2016. Based upon new scientific knowledge and new developments, this recommendation is an update based upon the best clinical evidence available. In addition to prospective randomised controlled clinical trials, this also includes studies with a lower level of evidence. In the absence of evidence, the decision is based on a consensus process within the members of the working group.The principle of making decision dependent on defect size has not been changed in the new recommendation either. The indication for arthroscopic microfracturing has been reduced up to a defect size of 2 cm 2 maximum, while autologous chondrocyte implantation is the method of choice for larger cartilage defects. Additionally, matrix-augmented bone marrow stimulation (mBMS) has been included in the recommendation for defects ranging from 1 to 4.5 cm 2 . For the treatment of smaller osteochondral defects, in addition to osteochondral transplantation (OCT), mBMS is also recommended. For larger defects, matrix-augmented autologous chondrocyte implantation (mACI/mACT) in combination with augmentation of the subchondral bone is recommended., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Objective: In total knee arthroplasty (TKA), range of motion has become established as an important factor. The criterion of quality is set to flexion of 90° after hospitalisation. Currently, it is supposed to be a predictor for 1‑year postoperative outcome. However, as this correlation has not been proven, this clinical trial was performed., Methods: A total of 182 TKA recipients were analysed retrospectively. Outcomes were assessed before surgery, after hospitalization, 6 weeks and 1 year post surgery. They included knee range of motion (ROM) to answer the main hypothesis, but also KSS, SF-36, WOMAC, EQ-5D and VAS to evaluate knee function and quality of life. The patients were divided into two groups differing in achieving 90° flexion after hospitalisation and compared 6 weeks and 1 year after surgery., Results: Knee flexion differed significantly between groups from 91 to 70° in the group without the aim of 90° flexion after hospitalisation (E) (p < 0.001). After 6 weeks, flexion was improved to 112° ± 13° (E > 90°) vs. 106° ± 14° (E < 90°; p = 0.001). One year post surgery, knee flexion averaged 122° ± 10° (E > 90°) vs. 120° ± 10° (E < 90°) with no difference between the groups (p = 0.57) and no significant difference in all other scores concerning knee function and quality of life., Conclusion: Flexion of 90° after hospitalisation is not adequate to predict medium-term outcomes after TKA. There is no advantage or disadvantage regarding whether the aim of 90° flexion is achieved., (© 2022. The Author(s).)

Winter sports represent a relevant entity for knee injuries due to their great popularity. In alpine skiing and snowboarding, knee joint injuries are the most common affected body regions, while in ice hockey they are in third place. Various accident mechanisms lead to different injury types and severities. In addition to medial collateral ligament injuries, anterior cruciate ligament injuries are of particular importance. In professional sports, severe combination injuries are more common. Therapy is exemplified using the anterior cruciate ligament rupture. The gold standard is replacement ligament surgery. The return-to-sport rate of 80% for skiing and snowboarding is comparable to summer sports such as football, basketball or baseball. For ice hockey, it is even better. Prevention is possible by targeted training programs, but also by optimizing the equipment and its adjustment., (© 2022. The Author(s).)

Arthrofibrosis of the knee joint is a severe complication following trauma and surgical procedures, which often results in long-term impairment of joint function. Early mobilization techniques and anesthesia are still employed without sufficient clarification of the underlying processes. While the early stages of arthrofibrosis can be successfully treated with conservative measures for pain reduction and wound healing, in the late stage tense collagenous scar tissue is frequently present that permanently limits joint mobility. In this stage an improvement of joint mobility has no chance of success without a surgical intervention. In surgical treatment a differentiation should be made between localized (mostly secondary) arthrofibrosis (e.g. cruciate ligament surgery) and generalized arthrofibrosis (in the majority of cases primarily after total knee arthroplasty) and the treatment planned accordingly. Comorbid pathological alterations (transplant position, instability of the total knee endoprosthesis, implant attrition, low-grade infection, patellofemoral instability or maltracking, patella baja) must be taken into consideration in the treatment. A multimodal accompanying treatment including physiotherapy, pain therapy and psychosomatics is necessary to ensure successful treatment., (© 2022. The Author(s).)

The physiotherapeutic and rehabilitative treatment of patients suffering from primary arthrofibrosis following total joint replacement or joint reconstruction is challenging for both patients and therapists. It can be successful if basic principles are applied. The necessary treatment techniques are presented in detail immediately postoperatively and in the subsequent rehabilitation process., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Arthrofibrosis (AF) is one of the most frequent complications of injuries and surgical interventions on joints, particularly after total knee replacement and anterior cruciate ligament reconstruction. Even though all joints can be affected, most cases involve the knee joint. Patients feel a painful impairment of the range of motion caused by fibrotic tissue formation within and sometimes also outside the joint. The normal healing process is disturbed by mechanical and emotional stressors and severe pain. In 90% of the cases AF occurs even within the first few days after the injury or surgery, so that the quality standards cannot be achieved. Physiotherapy and rehabilitation often do not result in a substantial amelioration of symptoms, so that the activities of daily living (ADL) are severely limited. The clinical diagnostics, differential diagnostics and a novel pathogenesis and stage model of the primary AF with the treatment principles derived from this are presented in this article., (© 2022. The Author(s).)

Background: After more than two decades of experience with computer-assisted knee arthroplasty, extensive experience and study data are available, allowing a profound evaluation. Undoubtedly, computer-assisted knee arthroplasty has been proven to achieve excellent results for implant positioning and long-leg axis reconstruction. Thus, computer-assisted knee arthroplasty represents the current gold standard to avoid unintended malpositioning of total knee components for neutrally aligned implants and individualized implant alignment (kinematic alignment, adjusted mechanical alignment, and others). Previous studies could not show significant differences in functional outcomes and patient satisfaction. However, recent meta-analyses showed relevant advantages of computer-assisted knee arthroplasty. These results could be based on further developments in software-assisted soft tissue balancing and more sensitive evaluation methods of follow-up examinations., Long-Term Outcome: Further, international registries show advantages of computer-assisted knee arthroplasty regarding long-term outcomes. In particular, the Australian arthroplasty registry describes a significantly lower revision rate due to aseptic loosening/osteolysis in the computer-assisted knee arthroplasty group, analyzing a period of up to 17 years. These positive effects can already be proven six months following surgery., Future Prospects: However, despite demonstrated benefits, computer-assisted knee arthroplasty has not yet become established in daily routine, and wide regional variations in its use are observed. Newer developments such as robotic-assisted knee arthroplasty, primarily based on navigation techniques, are currently being heavily promoted. However, this new technology must justify its enormous additional costs and prove its advantages compared to computer-assisted knee arthroplasty. In the backdrop of the development of computer-assisted knee arthroplasty, this might be a difficult task., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Objective: Rupture of the anterior cruciate ligament (ACL) in childhood and adolescence is a serious injury. It is now known that conservative therapy of an unstable knee joint in childhood or adolescence under can lead to poor subjective and objective results. The aim of this study is to record long-term results after transepiphyseal ACL reconstruction using autologous hamstring tendons and extracortical fixation in childhood and adolescence with open physes - at least 15 years after surgery., Methods: Our internal registry was used to identify all patients who received surgical treatment of an acl tear during childhood and adolescence by transepiphyseal acl reconstruction more than 15 years previously. In these patients, the International Knee Documentation Committee for Subjective Knee Form (IKDCsubj.), Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Score (TAS) and Lysholm Score were collected, and clinical and magnetic resonance imaging (MRI) examinations were performed., Results: A total of 22 patients were identified, 5 of whom could not be contacted. The mean age at the time of surgery was 13.1 years, and the mean follow-up time was 17.4 years. In 3 patients, a traumatic tear was observed with subsequent reconstruction of the ACL. None of the included patients showed a growth disorder during the course of the study. The IKDC subj. was 92.4 ± 14.7 (48 - 100), the Lysholm score was 87.9 ± 16.9 (34 - 100), the TAS was 5.7 ± 2.3 (3 - 9) and the pain level based on VAS was 3.5 ± 2.6 (1 - 8) points. The values showed subjective and objective deterioration compared to the 10-year results, with no statistical significance. The following subscores were reported for the KOOS: KOOS pain 90.9 ± 17.6 (28 - 100); KOOS symptom 82.9 ± 22.6 (11 - 100); KOOOS ADL 94.3 ± 13.7 (44 - 100); KOOS Sport 80.3 ± 26.4 (15 - 100); KOOS QOL 80.9 ± 25.8 (0 - 100). 13 of the 17 patients could also be clinically and radiologically examined. In 92% of patients, an intact acl reconstruction was found without evidence of cartilage or meniscus damage. The mean lateral difference in the KT-1000 measurement was 1.5 mm., Conclusion: ACL reconstruction in childhood and adolescence provides good functionality and stability of the knee joint over the long term. Secondary signs of osteoarthritis can only be detected in isolated cases by MRI. ACL reconstruction using the transepiphyseal technique can be considered the method of choice for open growth plate knee joints., Competing Interests: The authors declare that they have no conflict of interest./Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Objective: Open treatment of osteochondral defects of the knee to fully restore the bony defect and the articular surface., Indications: Focal, symptomatic osteochondral lesions of the knee with a depth of ≥ 5 mm and a surface of ≥ 1.5 cm 2 ., Contraindications: Osteoarthritis, kissing lesions, age > 50 years, untreated ligament instability or relevant malalignment, insufficient containment, inflammatory joint disease., Surgical Technique: Two-step procedure: Step 1 (arthroscopy): evaluation of the defect, harvesting of cartilage tissue for chondrocyte cultivation, if needed treatment of concomitant pathologies. Step 2 (open surgery): arthrotomy, preparation of the defect, transfer of iliac crest cancellous bone plugs to the defect, preparation of the cartilage defect (can exceed the size of the bony defect), matrix-guided autologous chondrocyte transplantation., Postoperative Management: Step 1: therapy follows the needs of concomitant procedures, with early full weight bearing as tolerated. Step 2: no suction drain, knee brace in extension for week 1, followed by stepwise increase of flexion, partial weight bearing for 6 weeks, continuous passive motion starting on postoperative day 1., Results: Since 2018, 8 patients (mean age 29.4 years) have been treated with the described technique. All patients were available for follow-up examination after an average of 12 months. The KOOS (Knee injury and Osteoarthritis Outcome Score) improved from 45.8 to 81.3 and the postoperative X‑rays showed bony healing of the cancellous bone plugs in all patients. The MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score reached 80.4 points., (© 2021. The Author(s).)

Objective: The goal of the modified Ellison operation as a supplement to a conventional anterior cruciate ligament (ACL) reconstruction is to decrease anterolateral rotational instability of a knee joint after ACL rupture, to improve the stability and prevent ACL re-rupture., Indications: An ACL rupture with high risk of re-rupture (young age, high-performance sport, hyperlaxity, contralateral ACL rupture in history), increased subjective and objective anterolateral rotational instability of the knee after ACL rupture, ACL re-rupture., Contraindications: Gonarthrosis, additive instabilities (e.g. posterolateral, medial), non-anatomical ACL reconstruction with persistent instability, general contraindications to surgery (e.g. infections), chronic irritation of the knee joint., Surgical Technique: Supine position. Mark the typical landmarks. Incision from Gerdy's tubercle extending proximally along the iliotibial tract (ITT) to the lateral collateral ligament (approx. 5 cm). Incise the ITT in the line of its fibers about 10 mm anterior to its posterior border and continue the incision proximally to 5 mm proximal to the LCL. Make a parallel incision 10-12 mm anterior to the first incision. Use sharp subperiosteal dissection to elevate the strip of the ITT from Gerdy's tubercle. Secure the distal end of the ITT strip with a nonabsorbable suture (e.g. FiberWire No. 2, Arthrex, Naples, USA). Expose the LCL and pass the ITT strip deep to the LCL from proximal to distal and back to Gerdy's tubercle. Reattach the distal end of the strip of the ITT to its original position at Gerdy's tubercle with a bone anchor. The defect in the ITT can be closed with an absorbable suture (e.g. Vicryl, Ethicon, USA) in the proximal part. Layered closure., Postoperative Management: Knee brace for at least 6 weeks, movement limitation of 0‑0-90° for 6 weeks, 2 weeks 20 kg partial weight bearing., Results: A total of 36 patients (mean age 18.9 years) with a high risk of ACL re-rupture have been treated with ACL reconstruction and modified Ellison procedure. Follow-up over 2 years. Of the patients 35 returned to the previous sports level, 1 patient suffered a re-rupture, 2 patients had cyclops resection and 1 patient contralateral ACL rupture., (© 2021. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Osteotomy close to the knee joint in cases of axial deformities or in the context of corrective interventions is still an elementary component of the spectrum of orthopedic surgery. The precise localization and analysis of the pathology are crucial in order to restore approximate physiological loading conditions by means of a suitable osteotomy procedure. Thus, above all, the medial open-wedge tibial osteotomy has become established as a standard procedure for the treatment of knee osteoarthritis caused by extra-articular tibial varus deformity. Furthermore, corrective osteotomy of the sagittal axis of the tibia and of the distal femur also show good long-term results when the indications are correctly interpreted. The osteotomies described in this article are corrections that should be performed after careful consideration of the biological and mechanical aspects. Correct planning, attention to risk factors and the surgical technique are the main factors that determine the long-term success of the procedure., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

The intra-articular osteoid osteoma (10% of cases) is a rare clinical finding. Based on atypical clinical signs and various radiological results the period to obtain a diagnosis and initiate the appropriate treatment is often very long. This case reports on a 32-year old female patient with knee pain on flexion and stress, which rarely occurred at night. Radiofrequency ablation (RFA) was contraindicated for IAOO in the trochlea femoris due to the direct subchondral location. Therefore, surgical rehabilitation by means of a cartilage-bone transplantation was carried out., (© 2022. The Author(s).)

The principals of growth arrest by epiphysiodesis and growth guidance by hemiepiphysiodesis are effective and powerful surgical techniques in pediatric orthopedics. These procedures can be used to correct leg length discrepancies as well as sagittal, coronal and oblique deformities. A differentiation is made between temporary and permanent techniques. The most significant advantage is that these techniques are minimally invasive and have low complication rates compared to acute osteotomy and gradual deformity correction. For optimal outcome an exact preoperative planning is needed to ensure accurate timing of the procedure, especially when permanent epiphysiodesis techniques are used. Although epiphysiodesis and hemiepiphysiodesis around the pediatric knee are most frequently used and can be considered the gold standard treatment of coronal plane deformities and leg length discrepancies, novel techniques for the hip and ankle are increasingly being performed. The successful clinical results with low complications support the broad use of hemiepiphysiodesis and epiphysiodesis for a variety of indications in the growing skeleton with deformities and leg length differences., (© 2022. The Author(s).)

Background: The aim of this study was to examine the influence of the COVID-19(coronavirus disease 2019) pandemic on the medical and physiotherapeutic follow-up care after reconstructions of the anterior cruciate ligament., Methods: 116 patients (72 men and 44 women) who had received a reconstruction of the anterior cruciate ligament between September 2019 and December 2020 were included in this study. These patients were divided into two groups depending on the date of surgery: one group that had received surgery in 2019 before the COVID-19 pandemic and one group that had undergone surgery in 2020 and was directly affected by the COVID-19 pandemic. All patients were interviewed using a standardized questionnaire regarding the influence of the coronavirus pandemic on the medical and physiotherapeutic follow-up care, as well as the moment of return to work. In addition, the range of motion of the respective knee 3 months postoperatively was analysed based on physical examination., Results: At 3 months postoperatively, patients who had undergone surgery in 2020 showed a clear trend towards a higher frequency of extension deficits of ≥ 5° (18.8% vs. 4.3%, p = 0.097) or an inability to bend the knee ≥ 120° (23.3% vs. 10%, p = 0.197) compared to those who had received surgery in 2019. Patients who had undergone surgery in 2020 reported significantly longer delays for appointments, a higher number of futile attempts to get an appointment and a higher number of cancelled appointments, regarding both medical and physiotherapeutic follow-up care. 34.9% of the patients who received surgery in 2020 indicated that they were able to reduce the duration of their sick leave due to the increased possibilities of working in a home-office situation during the pandemic. Alternative treatment options due to the pandemic were offered by 13.3% of the physiotherapists and 12.2% of the physicians., Conclusion: Although the physiotherapeutic and medical follow-up care was not directly affected by a "lockdown", the pandemic led to significant restrictions, which are also reflected in a clear trend towards worse clinical outcomes. Consequently, a further expansion of alternative treatment options, which were only offered by 12-13% of practices and that are presumably of comparable relevance for various other diseases, is needed., (© 2022. The Author(s).)

When a total knee arthroplasty (TKA) is implanted using the traditional mechanical alignment technique, this typically results in a straight leg, independently of pre-operative or even pre-arthrotic varus or valgus alignment. With mechanical alignment, we distinguish between 2 different alignment techniques: ligament balancing and bony referencing according to bony skeletal landmarks. In ligament balanced technique beside the straight mechanical axis, the prosthesis is implanted at 90° to the latter. The rotational alignment of the femur is set according to the ligament tension. In the skeletal referenced technique, the rotation of the femur is also set according to bony skeletal landmarks. As a variation of this technique, the prosthesis can be implanted with anatomical alignment. In this technique, the medial slope of the joint line of 3° in the frontal plane is respected during the implantation of TKA. Both techniques result in comparable long-term results with survival rates of almost 80% after 25 years. On the other hand, 15 - 20% of TKA patients report dissatisfaction with their clinical result. For more than 10 years now, the kinematic TKA alignment concept has been developed with the goal to achieve implantation that is adapted to the individual anatomy of the patient. The advocates of this technique expect better function of TKA. This strategy aims to reconstruct the pre-arthrotic anatomy of a given patient while preserving the existing joint line and the mechanical axis without performing ligamentary release. Studies have shown that the function of the prothesis is at least that good as in the conventional techniques. Long-term results are still sparse, but initial studies show that TKA implanted using the kinematic alignment technique exhibit comparable 10-year-survival rates to those implanted using the traditional mechanical alignment technique. Future studies need to show the limitations of this new technique and to identify patients who will or will not significantly benefit from this technique., Competing Interests: Both authors are consultants for Medacta, Castel San Pietro, Switzerland./Die Autoren sind Berater für Medacta, Castel San Pietro, Schweiz., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/).)

Objective: Supracondylar distal femoral osteotomy. Fixation with the contralateral TomoFix® (Fa. DePuy Synthes, Oberdorf, Switzerland) lateral distal femur plate. Use of the laterally reversed plate to improve the reconstruction of the sagittal anatomical axis of the leg., Indications: To correct knee flexion contractures with a deficiency of extension >20° at the age of 10 years., Contraindications: Surgical site infections or tumors., Surgical Technique: Ventral closed wedge osteotomy of the distal femur. Implantation of the locking compression TomoFix® lateral distal femur plate., Postoperative Management: Full weight bearing., Results: In all, 16 distal femoral osteotomies were performed in 9 patients. All patients had knee flexion contraction due to neurological disease. Patients with cerebral palsy showed a better GMFCS (gross motor function classification scale) level after surgery. Hardware was removed after 11.5 months (range: 9-18 months)., (© 2021. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Objective: Restoration of the extensor apparatus in the case of advanced tendon defects as part of revision total knee arthroplasty (TKA). Reconstruction and augmentation using vascularized gastrocnemius muscle and tendon., Indications: Advanced degeneration of the extensor apparatus (patella tendon; quadriceps tendon) with or without discontinuity, following revision arthroplasty., Contraindications: Persistent infection or pending TKA revision. Damaged gastrocnemius or soleus muscle or Achilles tendon., Surgical Technique: Extension of the surgical TKA-access medial-distally. Separation of the medial gastrocnemius muscle along the raphe and preparation of the distal tendon from the soleus portion. Transposition into the defect site, augmentation or reconstruction of the defect by double turn of the gastrocnemius tendon. The muscle belly serves to adequately cover the tendon as well as the ventral knee joint. Mesh coverage of the muscle., Postoperative Management: Immobilization of the knee and ankle for 10 days until mesh graft healing. Stepwise increasing flection of the knee with 30°/60°/90° every 2 weeks. Total weight bearing with secured full extended knee, no weight bearing with flexed knee for 6 weeks., Results: In 9 patients, 3 with complete rupture of the patellar tendon, 5 with destruction of the extensor apparatus, and 1 patient with rupture of the quadriceps tendon following TKA revision, good functional results were achieved with active extension of the knee joint and standing/gait stability 6 months after surgery., (© 2021. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

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