The study, conducted by researchers at Hospital for Special Surgery (HSS) in New York City, shows that a technique called the All-Inside, All-Epiphyseal ACL Reconstruction (AE) provides great knee stability and effectively controls joint stress.
"The AE technique is not available except in a few select centers around the country including HSS," said Frank Cordasco, M.D., surgical director of the Ambulatory Surgery Center and member of the Sports Medicine and Shoulder Service at HSS. "We believe the AE should be the preferred procedure for ACL reconstruction in the skeletally immature." The study will be presented on July 13 at the annual meeting of the American Orthopaedic Society for Sports Medicine (AOSSM), held in Baltimore.
Twenty years ago, very few children or adolescents presented at doctors' offices with ACL injuries. Today, these injuries are common because children and young adolescents are participating in sports earlier in life and at a higher level of competition. Young athletes are also increasingly specializing in one sport, putting them at risk for overuse injuries once only seen in professional athletes. In addition, since the Title IX ban on sex discrimination in school sports, the number of female athletes has increased and females are more prone to ACL injury.
Performing ACL reconstruction in patients who are still growing is difficult. The ACL can be thought of as a rope that connects the thighbone to the shinbone. The rounded ends of the thighbone and shinbone are called epiphyses and the ACL dangles between them. Open growth plates are located directly behind the epiphyses in children and adolescents, but not in adults.
In an adult ACL reconstruction, the torn ligament is removed from the knee, holes are drilled through the ends of the thighbone and shinbone, and a tissue graft is inserted in place of the removed ligament. In this way, the reconstruction mimics the natural ACL footprint. ACL reconstruction is difficult in children because if an adult-type reconstruction were performed, the graft would cross the growth plates, potentially causing damage that can result in uneven limb lengths or angular deformities. Thus, for many years, ACL injuries in children were managed with benign neglect, or surgical procedures that were not anatomic and required large incisions to avoid injuring the growth plate. In recent years, however, clinicians realized that non-operative treatment resulted in damage to menisci and articular cartilage thereby leading to early arthritis. Advances in technology, instrumentation and techniques are now available which allow surgeons to perform the AE reconstruction without risk of injury to the growth plate. These procedures are more technically demanding and are available at only a few centers around the country including HSS.
In the study, researchers, including Dr. Cordasco and HSS pediatric orthopedic surgeon Daniel Green, M.D., compared two ACL reconstruction techniques for children that minimize contact with the growth plate: the AE technique and the over-the-top reconstruction (OT). In the OT, surgeons slide a graft through a hole drilled into the shinbone, similar to an adult ACL surgery, but the graft is then attached to the back of the thighbone. The OT requires an open incision and does not mimic the natural ACL footprint. In the AE, surgeons mimic the adult surgery, but the ligament is only attached to the epiphysis and does not cross into the growth plate. The AE is performed arthroscopically and mimics the natural ACL footprint. While the AE has been around for ten years, it has been drastically refined in the last few years, due to advances in arthroscopic technologies.
The researchers obtained ten human cadaver legs that had their ACLs intact. They fixed the legs firmly in cement and, using a robot, they put each of the legs through a series of motions to test knee stress and strain. They tested stability when the knee was pivoting, for example, and they measured contact stresses by delivering pressure to the leg and evaluating the stress experienced at different areas of the joint.
The investigators then removed the ACLs and performed the same set of experiments, to replicate an ACL insufficient patient. They then performed all-epiphyseal procedures in five of the legs and over-the-top reconstructions in the other five, performed the same stress and stability experiments, and then reversed the order, so that each leg underwent both procedures.
The goal of ACL reconstruction is to stabilize a joint enough so that an individual can participate in sport without damaging other knee structures, but not to stabilize the knee so much that it overconstrains the knee. "If we overconstrain a joint, whether it is a knee or shoulder, you lose motion, but more importantly, you can develop an arthritic condition," said Dr. Cordasco. "Obviously in a ten year old, if you have an overconstrained joint, that is going to mean that by the time they are 30 or 40, they might need a joint replacement."
The researchers found that the AE and OT performed similarly, but the AE performed better when the knee was at 15 degrees, which is commonly experienced by individuals who are running down a field. In the experiments, the investigators actually used a thicker graft in the OT surgeries than would be used in actual patients, because they wanted to use the same size grafts in both AE and OT surgeries. Thus, in actual patients, OT surgeries would likely have resulted in worse outcomes.
While other studies have compared joint stability (kinematics) of the two procedures, this is the first to study contact stresses. "Both reconstructions improved the kinematics and contact stresses compared to the deficient state, but neither reconstruction completely restored normal kinematics and contact stresses," said Dr. Cordasco. "The OT had significantly higher contact stresses at 15% of flexion compared to the AE. This is important because most field and court sports involve knee function close to this position. The OT requires an arthrotomy, meaning an open incision, and therefore has increased morbidity with associated soft tissue trauma. We believe the AE is preferable in the pediatric and young adolescent population."
The study has been nominated for the 2012 Herodicus Award given annually by the Herodicus Society at the AOSSM meeting for the best paper submitted by an orthopedic resident or sports medicine fellow. Moira McCarthy, M.D., a fifth year orthopedic surgery resident at HSS will present the paper at 8:49 a.m. on July 13. Other HSS authors involved in the study were Scott Tucker, M.Eng., and Carl Imhauser, Ph.D.
About Hospital for Special Surgery
Founded in 1863, Hospital for Special Surgery (HSS) is a world leader in orthopedics, rheumatology and rehabilitation. HSS is nationally ranked No. 1 in orthopedics, No. 2 in rheumatology, No. 19 in neurology and No. 16 in geriatrics by U.S. News & World Report (2012-13), and is the first hospital in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center three consecutive times. HSS has one of the lowest infection rates in the country. From 2007 to 2011, HSS has been a recipient of the HealthGrades Joint Replacement Excellence Award. HSS is a member of the NewYork-Presbyterian Healthcare System and an affiliate of Weill Cornell Medical College and as such all Hospital for Special Surgery medical staff are faculty of Weill Cornell. The hospital's research division is internationally recognized as a leader in the investigation of musculoskeletal and autoimmune diseases. Hospital for Special Surgery is located in New York City and online at www.hss.edu.
Phyllis Fisher |
The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences