Proximity of the popliteal artery to the PCL during simulated knee arthroscopy: implications for establishing the posterior trans-septal portal

This study defines the sagittal distance from the posterior cruciate ligament (PCL) to the popliteal artery under simulated arthroscopic conditions. This information is relevant for posterior knee arthroscopy, particularly for the safe establishment of the posterior trans-septal portal. Measurements from the PCL to the popliteal artery were made on sagittal magnetic resonance images obtained in a previous study of 10 fresh-frozen cadaveric knees. The mean sagittal distance from the mid-PCL to the popliteal artery was 29.1 +/- 11 mm (range: 18-55 mm). The mean sagittal distance from the proximal PCL fovea to the popliteal artery was 9.7 +/- 5 mm (range: 3-16 mm). The results of this study provide the arthroscopist working in the posterior compartments of the knee with a more detailed knowledge of the anatomic relationship between the PCL and popliteal artery. This knowledge will help minimize the risk of iatrogenic vascular injury during arthroscopic knee surgery.     

Artificial intelligence,machine learning and the pediatric airway

Artificial intelligence and machine learning are rapidly expanding fields with increasing relevance in anesthesia and, in particular, airway management. The ability of artificial intelligence and machine learning algorithms to recognize patterns from large volumes of complex data makes them attractive for use in pediatric anesthesia airway management. The purpose of this review is to introduce artificial intelligence, machine learning, and deep learning to the pediatric anesthesiologist. Current evidence and developments in artificial intelligence, machine learning, and deep learning relevant to pediatric airway management are presented. We critically assess the current evidence on the use of artificial intelligence and machine learning in the assessment, diagnosis, monitoring, procedure assistance, and predicting outcomes during pediatric airway management. Further, we discuss the limitations of these technologies and offer areas for focused research that may bring pediatric airway management anesthesiology into the era of artificial intelligence and machine learning.     

Editorial Commentary: National Football League Hopefuls Beware: Your Stock May Be Falling After Anterior Cruciate Ligament Reconstruction

Making a National Football League (NFL) team is tough; making one after undergoing an anterior cruciate ligament (ACL) reconstruction is tougher. NFL Combine participants who are post-ACL reconstruction, particularly with certain graft types such as allografts and to a lesser extent hamstring grafts, are frequently ‘down-graded’ despite the presence of a stable, well-placed graft without any associated meniscal or chondral damage. Whether NFL general managers are truly prescient in accurately predicting decreased performance by choosing a player later in the draft, or whether NFL coaching staffs knowingly or unknowingly restrict an athlete's playing time based on draft position or surgical history is unknown. Yet, any collegiate football player who is good enough to make it to the Combine possesses a rare combination of athleticism, strength, determination, and toughness. An ACL tear used to mark the beginning of the end of an athlete's playing career, but today's athletes are able to return at an elite level following ACL injury and surgery. Unfortunately, despite a successful surgery, prospective NFL players who undergo ACL reconstruction may still be at a disadvantage compared to their uninjured counterparts in terms of their ability to be drafted and play in the first two years of their careers.     

Patellar Tendon Ruptures

Rupture of the patellar tendon is a relatively infrequent, yet disabling, injury, which is most commonly seen in patients less than 40 years of age. It tends to occur during athletic activities when a violent contraction of the quadriceps muscle group is resisted by the flexed knee. Rupture usually represents the final stage of a degenerative tendinopathy resulting from repetitive microtrauma to the patellar tendon. This injury may also occur during less strenuous activity in patients whose tendons are weakened by systemic illness or the administration of local or systemic corticosteroid medications. The diagnosis is made on the basis of the presence of a painful, palpable defect in the substance of the tendon; an inability to completely extend the knee against gravity; and the existence of patella alta confirmed by lateral radiographs. Ultrasonography and magnetic resonance imaging are useful in identifying a neglected rupture, as well as when the diagnosis is in question or an intra-articular injury is suspected. The prognosis after a patellar tendon rupture depends in large part on the interval between injury and repair. Surgery soon after the injury is recommended for optimal results. This is best accomplished by accurate reapproximation of the ruptured tendon ends, repair of the torn extensor retinacula, and placement of a reinforcing cerclage suture. An aggressive rehabilitation program, emphasizing early range-of-motion exercises, protected weight bearing, and quadriceps strengthening, will enhance the results of surgery. Patients who undergo delayed repair are at risk for a compromised result secondary to loss of full knee flexion and decreased quadriceps strength, although a functional extensor mechanism is likely to be reestablished.     

Treatment of multidirectionalshoulder instability in the athlete

Multidirectional instability in the athlete refers to symptomatic laxity of the shoulder in more than one direction.This is in contrast to unidirectional instability, which involves subluxation or dislocation in only one direction. The diagnosis and treatment of this disorder can be challenging owing to the unusual demands athletes place on their shoulders to be effective in their sport. The laxity required for overhand throwing, gymnastics, swimming, volleyball and tennis — while increased compared with that required for activities of daily living or with that of the opposite shoulder — must be symptomatic to be pathologic. Formerly, it was thought that generalized ligamentous laxity was a requirement for multidirectional instability, but now it is realized many athletes have multidirectional instability in the setting of otherwise normal ligamentous laxity. Nonoperative treatment is frequently successful in these athletes. When conservative management is unsuccessful, the capsular shift procedure has demonstrated good results in allowing these athletes to return to their sport. Arthroscopic and thermal capsulorrhaphy also offer other options for surgical treatment of this problem and will be briefly discussed.     

Intra-articular synovial sarcoma

A case of right knee intra-articular synovial sarcoma in a 26-year-old man is reported. The patient had experienced 12 to 18 months of chronic posterior right knee pain with flexion contracture of the leg. Magnetic resonance imaging (MRI) examination demonstrated nonspecific characteristics of a well-circumscribed, homogeneous mass within the posterior lateral compartment of the knee joint. The mass was isointense and hyperintense to muscle on T1- and T2-weighted sequences respectively, and initially clinically diagnosed as a localized tenosynovial giant cell tumor. However, histological examination showed the lesion to be a synovial sarcoma arising from the synovium of the knee joint. Synovial sarcoma may have a nonspecific MR appearance, especially when less than 5 cm in size, often simulating a less aggressive process. Primary intra-articular origin may predispose to earlier presentation, and therefore, radiological evaluation of smaller masses. Nonspecific MR characteristics of small, intra-articular masses provide a diagnostic dilemma. Synovial sarcoma should be considered in the differential diagnosis when distinguishing MR characteristics of other common joint-centered entities are not present.     

Mechanical properties of bioabsorbable meniscal arrows as a function of tear location: an ex vivo experimental study

BACKGROUND: Ex vivo studies have established that arrow fixation of meniscal tears is inferior to vertical sutures and is dependent on arrow length, although the influence of tear location is not known. HYPOTHESIS: Arrow length and tear location influence the mechanical properties of meniscal arrows. STUDY DESIGN: Controlled laboratory study. METHODS: A longitudinal incision was created either 2 mm or 7 mm from the periphery in 70 bovine medial menisci. Each was repaired with a meniscal arrow (10, 13, or 16 mm) or a single vertical suture and subjected to load-to-failure testing and video-graphic analysis. RESULTS: Mode of failure (P <.0001), maximum force (P <.0001), stiffness (P <.01), 2-mm gap force (P <.03), and ultimate gap formation (P <.002) were all directly related to arrow length. Sixteen-mm arrows and suture exhibited similar, superior mechanical properties. Tear location significantly influenced properties of 10-mm and 16-mm but not 13-mm arrows. Ten-millimeter arrows displayed the worst performance. CONCLUSIONS: Mechanical properties of meniscal arrows depend on tear location and arrow length. CLINICAL RELEVANCE: Sixteen-millimeter arrows are a possible alternative to suture for repair of central tears. Thirteen-millimeter arrows may be effective for central and peripheral tears. Ten-millimeter arrows should not be used.