Cancellous allogenic and autologous bone grafting ensure comparable tunnel filling results in two-staged revision ACL surgery

Objectives!#!Patients with recurrent instability after anterior cruciate ligament (ACL) reconstruction often present with enlarged or misplaced tunnels and bone grafting is required prior to the actual revision reconstruction. Autologous bone grafting features limited quantity and donor site morbidity. These problems may be eliminated utilizing cancellous bone allografts, but their efficiency and reliability have not been investigated systematically. The aim of the present study was to compare tunnel filling rates attained by utilizing either allogenic or autologous cancellous bone grafts.!##!Materials and methods!#!A total of 103 consecutive patients were enrolled retrospectively. All patients suffered from recurrent instability and underwent either allogenic or autologous cancellous bone grafting. Computed tomography (CT) was carried out before and after the bone grafting procedure. Based on preoperative CT scans, positioning and maximum diameter of the femoral and tibial tunnels were determined. Tunnel filling rates were calculated as a ratio of pre- and postoperative tunnel volumes. Primary outcome was the tibial tunnel filling rate. Femoral filling rates and density of the grafted bone were assessed secondarily.!##!Results!#!Preoperative CT scans revealed no significant differences between the two groups regarding distribution of misplacement and widening of the femoral or tibial tunnel. Postoperative CT scans were conducted after an interval of 5.2 months. Tunnel filling rates of 74.5% (± 14.3) femoral and 85.3% (± 10.3) tibial were achieved in the allogenic compared to 74.3% (± 15.9) femoral and 84.9% (± 9.4) tibial in the autologous group. With p values of 0.85 at the femur and 0.83 at the tibia, there were no significant differences between the groups. The density of the grafted bone revealed significantly higher values in the allogenic group.!##!Conclusions!#!Utilizing cancellous bone allografts in two-staged revision ACL surgery provides for sufficient and reproducible filling of enlarged or misplaced tunnels. The filling rates are comparable to those achieved with autologous bone grafting. Advantages of allografts are the unrestricted quantity and the absence of any harvesting procedure

Treatment of acute knee dislocations

Dislocation of the knee is a rare but severe injury. Knee dislocations occur mainly in young active male patients mainly due to high velocity injury mechanisms. Combined injuries of the anterior and posterior cruciate ligaments associated with injuries of the medial or lateral collateral ligaments are typical injury patterns in these cases. The early recognition and treatment of accompanying neurovascular injuries must be carefully considered and are decisive for the prognosis. Computed tomography angiography (CTA), X-radiography, magnetic resonance imaging (MRI) and fluoroscopic examination with the patient under anesthesia indicate the injury pattern and guide the treatment algorithm. According to current data conservative treatment seems to result in less favorable outcomes compared to surgical treatment. The decision-making process is influenced by multiple factors including injury pattern and associated injuries. The main aim of operative approaches is anatomically correct femorotibial alignment and stabilization of the knee joint. In the case of polytrauma or the presence of vascuar injuries, external fixation is recommended. Furthermore, reconstructive operative procedures in the first 14 days have advantages over delayed reconstruction procedures. Reconstruction strategies and techniques must be individually adapted to the injury pattern and are dependent among other things on hospital resources and experience of the surgeon. Despite optimal treatment and follow-up it is not uncommon for residual instability, functional and loading impairments to occur. Increased rates of early onset of arthrosis are to be expected

Diagnosis and treatment of rotatory knee instability

BACKGROUND Rotatory knee instability is an abnormal, complex three-dimensional motion that can involve pathology of the anteromedial, anterolateral, posteromedial, and posterolateral ligaments, bony alignment, and menisci. To understand the abnormal joint kinematics in rotatory knee instability, a review of the anatomical structures and their graded role in maintaining rotational stability, the importance of concomitant pathologies, as well as the different components of the knee rotation motion will be presented. MAIN BODY The most common instability pattern, anterolateral rotatory knee instability in an anterior cruciate ligament (ACL)-deficient patient, will be discussed in detail. Although intra-articular ACL reconstruction is the gold standard treatment for ACL injury in physically active patients, in some cases current techniques may fail to restore native knee rotatory stability. The wide range of diagnostic options for rotatory knee instability including manual testing, different imaging modalities, static and dynamic measurement, and navigation is outlined. As numerous techniques of extra-articular tenodesis procedures have been described, performed in conjunction with ACL reconstruction, to restore anterolateral knee rotatory stability, a few of these techniques will be described in detail, and discuss the literature concerning their outcome. CONCLUSION In summary, the essence of reducing anterolateral rotatory knee instability begins and ends with a well-done, anatomic ACL reconstruction, which may be performed with consideration of extra-articular tenodesis in a select group of patients

Correction: High-risk additional chromosomal abnormalities at low blast counts herald death by CML (Leukemia, (2020), 34, 8, (2074-2086), 10.1038/s41375-020-0826-9)

An amendment to this paper has been published and can be accessed via a link at the top of the paper