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Transphyseal Anterior Cruciate Ligament Reconstruction in Skeletally Immature Pubescent Adolescents, Mininder Kocher et al.; Journal of Bone and Joint Surgery, December 2007, Volume 89, pages 2632-2639. Comments: Reconstructing an ACL in a young patient requires that special consideration be given to the growth-disruption concerns associated with open growth plates. Kocher et al. describe a biomechanically sound, intra-articular reconstruction procedure that brings all the stability and normal-motion benefits of the adult procedure without the problematic compromises inherent to extra-articular (e.g. Tomato Stake) reconstructions. Kocher's hamstring-autograft transphyseal ACL reconstruction uses metaphyseal fixation to bring a superb outcome with very minimal risk of bone-growth disturbance.
For penetrating insight into female pediatric athlete ACL injuries and prevention avenues, please see the March 2006 articles Jump-Land Characteristics and Muscle Strength Development in Young Athletes -- A Gender Comparison of 1140 Athletes 9 to 17 Years of Age, by Sue Barber-Westin et al., and Effect of Gender and Maturity on Quadriceps-to-Hamstring Strength Ratio and Anterior Cruciate Ligament Laxity, by Christopher Ahmad et al., in the Female-Athlete Knee-Injury Incidence and Prevention Subsection. Assessment of Lower Limb Neuromuscular Control in Prepubescent Athletes, Sue D. Barber-Westin et al.; American Journal of Sports Medicine, December 2005, Volume 33, pages 1853-1860. Comments: This ground-breaking, penetratingly insightful study is the first to look at biomechanical knee-injury-predisposing factors in children (defined as young people who have not yet reached puberty). Barber-Westin notes that a large proportion of the prepubescent athletes studied exhibited a markedly inwards-angled (valgus, hence simulating knockkneedness) knee alignment during the drop-jump screening test. Also noted were off-balance, asymmetrical landings during the hop tests. Given that these inwards-angled and off-balance landings appear to be correlated with knee-ligament injuries in older athletes, Barber-Westin concludes that neuromuscular training may constitute an appropriate intervention measure. Such training may be big dividends later on, not only in terms of avoided knee injuries, but also in terms of improved athletic performance (e.g. higher jump height, greater endurance). Note that the use of a single consumer-grade video camera makes the assessments done in this study easy for trainers to do in the field, since no special equipment is required.
Physeal Sparing Reconstruction of the Anterior Cruciate Ligament in Skeletally Immature Prepubescent Children and Adolescents, Mininder S. Kocher et al.; Journal of Bone and Joint Surgery, American Edition, November 2005, Volume 87, pages 2371-2379.Comments: This article describes a useful method for ACL reconstruction in pediatric patients with open physes. It must be borne in mind that this combination intraarticular-extraarticular method is nonanatomic. In other words, the resulting grafted ACL does not emulate the natural ACL very well, since the grafted ACL is not isometrically located. Therefore, the result of such a reconstruction, though adequate, is biomechanically suboptimal...and so the knee will have some unbidden laxity if it is not to be too tight at certain points in the range of motion. When the patient reaches adulthood, the ACL can be reconstructed using standard intraarticular tendon-grafting, or the knee can be left as is. Please be certain to read the commentary by Dr. Frank Noyes, in particular with regards to long-term follow-up. (Ideally, anyone who incurs any knee injury should be followed up at regular intervals for the rest of their life.) This article also includes a letter to the editor by Charles John Wakeley.
For a comprehensive overview of all the major considerations pertaining to treatment of ACL injuries (including a discussion of pediatric ACL treatment options), please see the October 2005 article Clinical Sports Medicine Update: Treatment of Anterior Cruciate Ligament Injuries, Part I, by Bruce D. Beynnon et al., in the ACL Reconstructions via Patellar-Tendon Autografts (includes also Quadriceps Tendon Autografts) Subsection. For insight into age-related (and also gender-related) discrepancies in leg-muscle strength and other biomechanical factors germane to ACL injuries in young people, please see the September 2005 article Isokinetic profile and differences in tibial rotation strength between male and female athletes 11 to 17 years of age, by Noyes and Barber-Westin, in the Female-Athlete Knee-Injury Incidence and Prevention Subsection. Clinical Sports Medicine Update: Anterior Cruciate Ligament Injuries in Children With Open Physes -- Evolving Strategies of Treatment, Chris P. Bales et al.; American Journal of Sports Medicine, December 2004, Volume 32, pages 1978-1985. Comments: This article provides a good overview of the evolving strategies for dealing with torn ACLs in children (herein defined as being skeletally immature, hence with open growth plates [physes]). The authors note that nonoperative treatment (i.e. muscle-strengthening, use of bracing, activity modification) tends to be unsatisfactory, and children with chronic ACL tears fare no better than adults (i.e. their knees exhibit osteoarthritic degeneration just like those of older, chronically unstable knees). Because standard ACL-reconstruction techniques entail the drilling of bone tunnels, such methods would entail violating the growth plates in skeletally immature people. So, modified methods, known as "physeal-sparing" techniques, were introduced. Some of these involved a semi-extraarticular reconstruction. The problem is that these methods tended to result in a biomechanically suboptimal result. This led to the development of "physeal-respecting" approaches. The authors describe this as follows: small holes are drilled through the physes, and a soft-tissue (e.g. hamstring) graft is used in order to avoid the concern of bridging the growth plates with bone plugs (as would be the concern if the patellar-tendon graft were used). Fixation hardware is placed as closed as possible to the joint, so as to give maximum stiffness to the graft (i.e. no bungee-cord effect) and also to keep the hardware away from the growth plates. This "physeal-respecting" approach brings good success, since it not only restores knee stability (thereby averting the rapid deterioration of the knee that would result if the joint were left unstable until adulthood), but it also results in a knee motion that is as close to normal as in the standard adult ACL-reconstruction methods.
ACL Reconstruction with Open Physes, Frank R. Noyes et al.; presented at Frontiers in Sports Medicine: The Athlete in 2003, March 14, 2003. Comments: This is a superb synopsis of the options available for adolescents with torn ACLs, and it reviews all the research done to date. (The document is in the form of a handout for a presentation, and it includes a number of diagrams and figures. It was created by Sue Barber-Westin using Microsoft Word, and should be openable with most word-processing software packages, including Lotus AmiPro, Corel WordPerfect, as well as Unix/Linux-based OpenOffice and Sun StarOffice. If you prefer the document in Rich Text Format, please e-mail Michael Frind at frind@execulink.com.)
For insight into meniscal repair (given that meniscal injuries very often accompany ACL tearing), please see the July 2002 article Arthroscopic Repair of Meniscal Tears Extending into the Avascular Zone in Patients Younger Than Twenty Years of Age, by Noyes and Barber-Westin, in the Meniscal Injuries: Causes, Consequences and Treatments Subsection. For insight into soft-tissue autograft anchorage (given that this type of autograft is the standard choice for pediatric-ACL-injury treatment), please see the ACL Reconstructions via Soft-Tissue (e.g. Hamstring) Autografts (includes articles focused on graft-fixation techniques/devices) Subsection. Delayed Anterior Cruciate Ligament Reconstruction in Adolescents With Open Physes, G. William Woods et al.; American Journal of Sports Medicine, Baltimore, January 2004, Volume 32, pages 201-210. Comments: For skeletally immature ACL-deficient people, Woods et al. found that delaying ACL reconstruction until adulthood is a viable option if (and only if) activities are restricted to non-knee-demanding involvements (specifically, no sports which entail jumping or planting and twisting), and if (and only if) the knee is not giving way during regular daily-living activities. Failure to adhere strictly to such restrictions can be expected to engender repeated giving-way incidents, whereupon massive, cumulative, and permanent damage to the unstable knee may occur (in the form of additional damage to articular cartilage and menisci, as well as stretching-out of the secondary-restraint structures, therefore loosening of the in the knee in general). With this delayed-ACL-reconstruction concept, after the growth plates have closed, standard, anatomically-appropriate ACL reconstruction (i.e. intra-articular reconstruction with isometric graft placement) is done in the same way as it is done for people who incur ACL tears in adulthood. The authors note that children who are unwilling to adhere to activity restrictions (or whose parents are unwilling to ensure that such activity restrictions are adhered to), or who have promising athletic careers ahead of them, would be ideal candidates for physeal-sparing ACL-reconstruction techniques (along with likely a second ACL reconstruction, this time using a standard adult-style intraarticular method, once adulthood has been reached).
Preoperative Evaluation and Anterior Cruciate Ligament Reconstruction Technique for Skeletally Immature Patients in Tanner Stages 2 and 3, Vincenzo Guzzanti et al.; American Journal of Sports Medicine, Baltimore, November 2003, Volume 31, pages 941-948. Comments: This article follows from and cites Guzzanti-AJSM-Nov03.shtml. The authors describe the preoperative evaluation process, including assessment of skeletal age. Because in the herein described reconstruction method the bone tunnels traversed the growth plates, soft tissue (hamstring) grafts were in any case the only option. (Patellar-tendon grafts have bone plugs at both ends, and these would have cause premature closure of the growth plates in the vicinity of the tunnels.) One truly worrisome aspect of the procedure detailed herein is how it compromises the hamstring group. Given that hamstring strength is valuable both physiologically (i.e. athletic performance) as well as in protecting the ACL (both against injurious hyperextension-type forcing as well as against anterior drawer), and given that any hamstring-grafting procedure (including the proximal-release method detailed by Guzzanti as well as the more typical DLSTG tendon-portion-stripping procedure often used in adults) can be counted on to bring a permanent weakening of the hamstring group, this constitutes serious cause for concern. (Concerns of hamstring-strength loss are especially acute if the patient happens to be female, because females tend to have weak hamstrings in any case; additionally, female athletes are 2-8 times as prone to incurring ACL injuries as their male counterparts.) It must be kept in mind that being very young does not exempt a child from the baleful degenerative changes that are almost guaranteed to occur in an ACL-deficient knee that is allowed to repeatedly manifest itself as unstable. The concerns of chronic knee instability are especially acute if bone-bruising and/or meniscal tearing are present as well; participation in plant-and-twist (cutting-type) sports heightens the concerns even more. It is for these reasons that pediatric ACL reconstructions have become more commonplace in the world of modern orthopedics.
Physeal-Sparing Intraarticular Anterior Cruciate Ligament Reconstruction in Preadolescents, Vincenzo Guzzanti et al.; American Journal of Sports Medicine, Baltimore, November 2003, Volume 31, pages 949-953. Comments: This method, using a hamstring-type graft but with a staple in the femur (and with an oblique tibial bone tunnel), does bring the advantage of not violating the growth plate. But one very frightening possibility is that the staple conceivably could pull out. And, because at the staple the graft does not make much contact with the bone, secure graft-to-bone healing might not occur. Furthermore, because the graft is looped around the staple, it could rotate around it whenever the knee is moved; this could hamper effective graft incorporation. (Although no evidence of graft impingement was noted in any of the patients, there remains the question of sufficient room for the graft at the femoral end, given that Guzzanti's method did not entail performing notchplasty [i.e. the widening of the intercondylar notch that is a standard part of modern ACL-reconstruction procedures], particularly given that the patient is still growing. Keep in mind that this method involves looping of both the semitendinosus and gracilis tendons [shown together as a single strand in Figure 1 of this article] around a staple, and then sewing them together. This is in contrast to the standard procedure of doubling the tendons and sewing them together before installing them. Additionally, Guzzanti's heavy use of fluoroscopy during the surgery is in itself cause for concern, particularly since the patients are young children. A fluoroscope is basically an X-ray video camera. The problem is that it continually exposes the tissue being imaged to X-rays throughout the viewing period. A standard still-film-type X-ray exposure lasts for 1/50 [using ASA 400 film] or 1/100 of a second [for the newer ASA 800 film], and thus each second that a patient is under a fluoroscope translates into the ionizing-radiation exposure that would have been received with 50 or 100 standard film-type X-ray images!) Long-term follow-up (i.e. at least several decades, and preferably for at least a half-century) of the patients would be needed in order to see whether or not this method results in a permanent surrogate ACL that lasts not only for as long as the child is a child, but for said person's entire adult life as well. (One further point: the graft is obtained by detaching both the semitendinosus and gracilis tendons at their proximal ends, and using them for the grafting directly. Because the tendons remain connected at the distal end, they still have a blood supply and hence don't die off like in the standard autografting procedure, which entails stripping out a tendon portion and implanting the resulting dead sliver of tissue. However, the loss of both the semitendinosus and gracilis tendons in their entirety is worrisome, given that this will permanently reduce hamstring-group strength. The hamstrings are essential in protecting the ACL (whether natural or a surrogate obtained through reconstruction), and any loss in hamstring-group strength is very worrisome.
Anterior Cruciate Ligament Injury in
Paediatric and Adolescent Patients: A Review of Basic Science and Clinical Research, Kevin G Shea et al.; Sports Medicine, May 2003, Volume 33, Number 6, pages 455-471. Comments: This article gives a comprehensive overview of past research, and discusses the options and possibilities available when one is confronted with a torn ACL in a skeletally immature person. At present, the best options entail soft-tissue grafting, for example using the hamstring-group tendons. (As Aichroth showed in 2002, it appears safe for the bone tunnels to cross the growth plates, as long as care is taken to keep graft-fixation devices as far away as possible from the growth plates.) In any case, the graft should be placed isometrically (i.e. so that its length is not being forced to change as the knee moves throughout its range of motion, therefore avoiding the danger of the graft stretching out and subsequently failing); this can only be done with intra-articular graft placement. (The Micheli method, a popular option which entails an extra-articular reconstruction using the iliotibial band [ITB], very nicely avoids violating the growth plates, but unfortunately, it is biomechanically suboptimal.) Shea et al. note that simply giving the young patient a brace and recommending activity modification tends of be a little value. Because it is very difficult for a child to completely discontinue knee-demanding activities until skeletal maturity is reached, if the non-surgical route is followed, repeated giving-way incidents (and therefore severe, cumulative, and permanent degenerative changes in the knee [including not only meniscal tearing as well as articular-cartilage damage via bone-bruising, but also ever-increasing looseness of the secondary restraints as well as meniscal erosion due to abnormally loose knee motion], exactly as would occur in a chronically unstable adult knee) must be anticipated. The authors provide a penetratingly insightful critique into all the previous studies done in the realm of pediatric ACL reconstruction, and they note that the need for further study still remains.
The Relationship of the Femoral Origin of the Anterior Cruciate Ligament and the Distal Femoral Physeal Plate in the Skeletally Immature Knee: An Anatomic Study , Christopher T. Behr et al.; American Journal of Sports Medicine, November 2001, Volume 29, pages 781-787. Comments: This cadaver-type study discusses the relationship between the ACL's femoral origin ACL to distal femoral physeal plate in the immature knee. The authors warn that when an over-the-top femoral ACL-graft placement is used, care must be taken to avoid the femoral growth plate.
Effects of a Tensioned Tendon Graft in a Bone Tunnel Across the Rabbit Physis, Jean-Benoit Houle et al.; Clinical Orthopaedics and Related Research, October 2001, Volume 391, pages 275-281. Comments: This intriguing study shows how placing a tensioned soft-tissue graft can affect the growth plates (physes). (This is a laboratory-animal study, although the rabbit model is well-accepted with regards to orthopedic-surgery studies.)
The Effect of Placing a Tensioned Graft Across Open Growth Plates: A Gross and Histologic Analysis, T Bradley Edwards et al.; The Journal of Bone and Joint Surgery (American Edition), May 2001, Volume 83, pages 725-734. Comments: This study uses the canine model to simulate what can happen when a soft-tissue ACL graft is installed. The authors note, however, that more research into graft geometry and graft tension are required. (In this study, the graft was installed with substantial tension; also, the geometry may have been non-isometric, given that the anatomy of a beagle's knee is almost certainly quite different from that of the average human knee. Humans walk on two legs, and our knees have evolved for bipedal ambulation. In contrast, dogs walk on four legs. This quadrupedal configuration which enables excellent acceleration and instantaneous direction-change capabilities, and it explains why chasing a runaway dog is almost guaranteed to be futile.)
Anterior Cruciate Ligament Reconstruction In Adolescents With Open Physes, Eric R. Aronowitz et al.; American Journal of Sports Medicine, Baltimore, March 2000, Volume 28, pages 168-175. Comments: Aronowitz et al. describe a method for pediatric ACL reconstruction using an Achilles tendon allograft. (The procedure was only carried out in ACL-deficient children 14 years of age or more; the authors describe the procedure for determing skeletal age.) The authors found the method to be successful, with no ensuing leg-length discrepancies noted. By using soft-tissue grafting, there is no concern of the growth plates (epiphyses) being bridged, as there would be if patellar-tendon autografting had been employed. Note that all patients in this study underwent examination under anesthesia (which entails performing the manual-manipulation and drawer tests, but without the worry of muscle tenseness masking ligament tears).
Anterior Cruciate Ligament Reconstruction in Patients Who Are Prepubescent, Lyle J. Micheli et al.; Clinical Orthopedics and Related Research, July 1999, Volume 364, pages 40-47. Micheli et al. describe how they obtained good results by using the iliotibial band to reconstruct the ACL in pediatric patients. This extra-articular method retains the attachment of the iliotibial band at one end, and loops it around through obliquely-drilled holes. This method avoids compromising the growth plates and therefore circumvents potential concerns of growth arrest and angular deformity. But additionally, because this method does not entail harvesting any graft material from the hamstring area, it also avoids compromising the hamstring group. (This is a major advantage, given the biomechanical importance of the hamstring group, both in terms of knee functioning and in terms of ACL-injury/reinjury prevention.) Although Micheli recommends that this method be presented as being temporary in nature (given that this method makes the knee anatomically and physiologically rather abnormal, especially when compared to the standard intra-articular tendon-grafting procedures used in adults), he notes that the patients in the study (at time of publication) had not yet required revision reconstruction.
Valgus Deformity After Reconstruction of the Anterior Cruciate Ligament in a Skeletally Immature Patient. A Case Report, Jon D. Koman et al.; The Journal of Bone and Joint Surgery (American Edition), February 2000, Volume 82, pages 711-715. Comments: This study shows what can happen if a pediatric ACL reconstruction is performed incorrectly. Although in this case a soft-tissue graft was used (and so there was no concern of graft bone plugs bridging the growth plates [physes], as would have been the concern if a patellar-tendon autograft had been chosen), the graft-anchorage device (a cannulated transverse transfixing screw) was installed so that it crossed the femoral growth plate on the lateral side. The result was that the growth plate closed prematurely on the lateral side, thereby resulting in the young patient being left with knockkneedness. A tibial osteotomy, to correct the valgus angulation, was needed. (This article includes follow-up in the form of a letter to the editor by O.O. Oni; also present is the author's response.)
Anterior Cruciate Ligament Tears in Children, Jeff Guttman; A.I. Dupont Institute, Wilmington, DE; April 1, 1996. Comments: This article provides a brief, easy-to-read overview of ACL injuries in children. Patellar Tendon Graft Reconstruction for Midsubstance Anterior Cruciate Ligament Rupture in Junior High School Athletes: An Algorithm for Management
, John R. McCarroll, K. Donald Shelbourne, et al.; American Journal of Sports Medicine, July 1994, Volume 22, Number 4, pages 478-484. Comments: In this study, ACL-deficient children received patellar-tendon autografting. The authors reported good results, with no incidents of growth abnormalities. However, the authors were careful to only perform this surgery in cases where the physes (growth plates) were closing, not "wide open".
Anterior Cruciate Ligament Allograft Reconstruction in the Skeletally Immature Athlete, Michelle Andrews, MD, Frank P. Noyes, MD, and Sue D. Barber-Westin; American Journal of Sports Medicine, January 1994, Volume 22, Number 1, pages 48-54. Comments: This insightful study is one of the first to delve thoroughly into the topic of a modified intraarticular soft-tissue ACL reconstruction in the skeletally immature athlete. The authors describe in detail a method which, despite entailing some growth-plate penetration, did not bring any observed growth arrest. (The tibial tunnel is drilled through the centre of the growth plate, thereby avoiding the periphery of the plate and therefore avoiding concerns of angular growth deformities.) The authors do, however, recommend delaying intraarticular ACL reconstruction until skeletally maturity has been reached, or unless the patient has years of growth remaining, or if the patient has a very strong desire to continue athletics as soon as possible, or if the knee manifests giving-way during daily-living activities.
Anterior Cruciate Ligament Injuries in Patients with Open Physes, Andrew W. Parker et al.; American Journal of Sports Medicine, January 1994, Volume 22, pages 44-47. Comments: This older study describes a non-growth-plate-violating extra-articular hamstring-tendon ACL-reconstruction method. Despite the non-isometric and non-anatomic grafting (therefore bringing very large variations in graft tension throughout the knee range of motion), satisfactory results where obtained (within the follow-up period of approximately 3 years).
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