Three-portal technique for anterior cruciate ligament reconstruction: Use of a central medial portal

Standard endoscopic reconstruction of the anterior cruciate ligament (ACL) is performed with the use of 2 arthroscopic portals. The surgical error most commonly associated with ACL reconstruction is improper positioning of the tunnel. Errors in femoral tunnel position may be related to poor visualization of the lateral wall. When anatomic double-bundle ACL reconstruction is performed, proper visualization of the lateral wall is essential to ensure correct placement of both tunnels. We propose the use of a central portal, in addition to more standard anterolateral and anteromedial portals, to enhance visualization of the lateral wall. In addition, the arthroscope can be moved interchangeably throughout the portals during the procedure for improved viewing during specific steps. An accessory anteromedial portal placed inferiorly and medially allows placement of the femoral tunnels while providing a high central anteromedial portal for best visualization of the lateral wall. As a result, no notchplasty is required, and a more anatomic reconstruction can be performed

Three-Dimensional Anatomic Evaluation of the Anterior Cruciate Ligament for Planning Reconstruction

Anatomic study related to the anterior cruciate ligament (ACL) reconstruction surgery has been developed in accordance with the progress of imaging technology. Advances in imaging techniques, especially the move from two-dimensional (2D) to three-dimensional (3D) image analysis, substantially contribute to anatomic understanding and its application to advanced ACL reconstruction surgery. This paper introduces previous research about image analysis of the ACL anatomy and its application to ACL reconstruction surgery. Crucial bony landmarks for the accurate placement of the ACL graft can be identified by 3D imaging technique. Additionally, 3D-CT analysis of the ACL insertion site anatomy provides better and more consistent evaluation than conventional “clock-face” reference and roentgenologic quadrant method. Since the human anatomy has a complex three-dimensional structure, further anatomic research using three-dimensional imaging analysis and its clinical application by navigation system or other technologies is warranted for the improvement of the ACL reconstruction

The Effect of Muscle Fatigue on Muscle Force-Couple Activation of the Shoulder

Context: Muscle fatigue is an important concept in regard to the muscle function of the shoulder joint. Its effect on the muscle force couples of the glenohumeral joint has not been fully identified. Objective: To examine the effects of muscle fatigue on muscle force-couple activation in the normal shoulder. Design: Pretest, posttest. Patients: Ten male subjects, age 18Ð30 years, with no previous history of shoulder problems. Main Outcome Measures: EMG (area) values were assessed for the anterior and middle deltoid, subscapularis, and infraspinatus muscles during 4 dynamic stabilizing exercises before and after muscle fatigue. The exercises examined were a push-up, horizontal abduction, segmental stabilization, and rotational movement on a slide board. Results: No significant differences were observed for any of the muscles tested. Conclusions: The results of our study indicate that force-couple coactivation of the glenohumeral joint is not significantly altered after muscle fatigue

Increased medial tibial slope in teenage pediatric population with open physes and anterior cruciate ligament injuries

Variations in bony morphology have been associated with anterior cruciate ligament (ACL) injury risk. The primary aim of this study was to compare the tibial slope in the teenage pediatric population with open physes, with and without ACL injury. The secondary aims were to compare the notch width index (NWI) and determine the influence of gender and age on tibial slope and NWI. Thirty-nine teenage pediatric subjects were included in this study, 16 with and 23 without ACL injury. Medial tibial slope and lateral tibial slope and NWI as measured on plain radiographs were compared between the groups using an independent t-test. Comparison of tibial slope and NWI was also performed between male and female subjects. Pearson correlation coefficient between age and tibial slope and NWI was calculated. The medial tibial slope averaged 10.2 (±3.9) degrees, the lateral tibial slope 11.5 (±3.9) degrees, and the NWI 0.26. There was a significant difference in medial tibial slope between the ACL-injured (12.1 degrees) subjects and the controls (8.9 degrees) (P = 0.009). There was no significant difference in lateral tibial slope or NWI between the groups. There was no significant difference in the medial tibial slope and lateral tibial slope and NWI between the male and female subjects. Subject age was not correlated with medial tibial slope and lateral tibial slope or NWI. There was an increased medial tibial slope in ACL-injured teenagers with open physes, when compared to a control group of teenager with open physes without ACL injur

Anatomska rekonstrukcija prednjeg križnog ligamenta

Tears of the anterior cruciate ligament (ACL) are one of the most common injuries to active individuals. The history of reconstructing a ruptured ACL has undergone many advances from open, extra-articular reconstructions, to modern day advanced arthroscopic techniques. Some of these new arthroscopic techniques use small incisions and standardized instruments reducing the surgical time, however, they fail to restore the native ACL anatomy. Recent studies have shown that non-anatomical reconstruction might result in suboptimal clinical outcomes. As a result, anatomic ACL reconstruction has gained popularity. The cornerstone of anatomic ACL reconstruction is the functional restoration of the ACL to its native dimensions, collagen orientation, and insertion sites. This article is meant to provide the most up-to-date literature review regarding anatomic ACL reconstruction.Ozljede prednjeg križnog ligament (PKL) spadaju među najčešće sportske ozljede koljena. Povijest rekonstrukcije PKL-a prešla je dug put od otvorenih metoda do današnji modernih artroskopskih tehnika. Pri nekim artroskopskim tehnikama koriste se male incizije uz upotrebu standardiziranih instrumenata, čime se značajno skraćuje vrijeme operacije, ali se ne uspijeva u cijelosti rekonstruirati anatomsko hvatište PKL-a. Novije studije pokazale su da se takvim rekonstrukcijama ne uspijevaju postići zadovoljavajući klinički rezultati. Cilj anatomske rekonstrukcije jest rekonstukcija prirodne duljine i promjera PKL-a, orijetnacije kolagenih vlakana i anatomskih hvatišta. U ovom radu dajemo pregled najnovije literature koja se bavi anatomskom rekonstrukcijom PKL-a

Predictions of Anterior Cruciate Ligament Dynamics From Subject-Specific Musculoskeletal Models and Dynamic Biplane Radiography

In vivo knee ligament forces are important to consider for informing rehabilitation or clinical interventions. However, they are difficult to directly measure during functional activities. Musculoskeletal models and simulations have become the primary methods by which to estimate in vivo ligament loading. Previous estimates of anterior cruciate ligament (ACL) forces range widely, suggesting that individualized anatomy may have an impact on these predictions. Using ten subject-specific (SS) lower limb musculoskeletal models, which include individualized musculoskeletal geometry, muscle architecture, and six degree-of-freedom knee joint kinematics from dynamic biplane radiography (DBR), this study provides SS estimates of ACL force (anteromedial-aACL; and posterolateral-pACL bundles) during the full gait cycle of treadmill walking. These forces are compared to estimates from scaled-generic (SG) musculoskeletal models to assess the effect of musculoskeletal knee joint anatomy on predicted forces and the benefit of SS modeling in this context. On average, the SS models demonstrated a double force peak during stance (0.39–0.43 xBW per bundle), while only a single force peak during stance was observed in the SG aACL. No significant differences were observed between continuous SG and SS ACL forces; however, root mean-squared differences between SS and SG predictions ranged from 0.08 xBW to 0.27 xBW, suggesting SG models do not reliably reflect forces predicted by SS models. Force predictions were also found to be highly sensitive to ligament resting length, with ±10% variations resulting in force differences of up to 84%. Overall, this study demonstrates the sensitivity of ACL force predictions to SS anatomy, specifically musculoskeletal joint geometry and ligament resting lengths, as well as the feasibility for generating SS musculoskeletal models for a group of subjects to predict in vivo tissue loading during functional activities

Technical Considerations in Revision Anterior Cruciate Ligament Reconstruction for Operative Techniques in Orthopaedics

As the incidence of anterior cruciate ligament (ACL) reconstruction continues to increase, the rate of revision surgery continues to climb. Revision surgery has inherent challenges that must be addressed to achieve successful results. The cause of the primary ACL reconstruction failure should be determined and careful preoperative planning should be performed to address the cause(s) of failure. Each patient undergoing revision surgery should undergo a thorough history and physical examination, receive full-length alignment radiographs, lateral radiographs, 45° flexion weight-bearing posteroanterior radiographs, and patellofemoral radiographs. The 3-dimensional computed tomography scan should be performed to assess tunnel position and widening. Magnetic resonance imaging should be used to assess for intra-articular soft tissue pathology. Meniscal tears, meniscal deficiency, anterolateral capsule injuries, bony morphology, age, activity level, connective tissue diseases, infection, graft choice, and tunnel position can all affect the success of ACL reconstruction surgery. Meniscal lesions should be repaired, and in cases of persistent rotatory instability, extra-articular procedures may be indicated. Furthermore, osteotomies may be needed to correct malalignment or excess posterior tibial slope. Depending on the placement and condition of the original femoral and tibial tunnels, revision surgery may be performed in a single procedure or in a staged manner. In most cases, the surgery can be performed in one procedure. Regardless, the surgeon must communicate with the patient openly regarding the implications of revision ACL surgery, and the treatment plan should be developed in a shared fashion between the surgeon and the patient

Erratum to: The pivot shift: a global user guide

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Transfer of LacZ Marker Gene to the Meniscus

Background: Lesions in the avascular two-thirds of the meniscus do not heal well and are of concern clinically. Various growth factors promote the synthesis of matrix by meniscal cells and thus have the potential to augment healing. However, their clinical application is severely hindered by problems with delivery. An attractive approach to overcoming such problems is to transfer genes that encode the growth factors in question to the site of the injury. As a prelude to this, we evaluated methods for delivering genes to the meniscus. Methods: Gene transfer was evaluated in vitro and in vivo with a lacZ marker gene, which expresses the enzyme β-galactosidase. Two types of vectors were tested: an adenovirus and a retrovirus. Monolayers of lapine, canine, and human meniscal cells, as well as intact lapine and human menisci, were used for the in vitro studies. Lesions were created in the menisci of rabbits and dogs for the in vivo studies. Gene transfer to the sites of the experimental meniscal lesions in vivo was accomplished in two ways. In the lapine model, a suspension of adenovirus carrying the lacZ marker gene was mixed with whole blood and the clot was inserted into the lesion. In the canine model, retrovirally transduced allogenic meniscal cells carrying the lacZ marker gene were embedded in collagen gels and transferred to the defects. The animals were killed at various time-points, and gene expression was evaluated by histological examination of sections stained with 5-bromo-4-chloro-indolyl-β-D-galactose (X-gal), from which a blue chromagen is released in the presence of β-galactosidase. Results: Monolayer cultures of lapine, canine, and human meniscal cells were susceptible to genetic transduction by both adenoviral and retroviral vectors. In vitro gene transfer to intact human and lapine menisci proved possible both by direct, adenoviral, delivery and indirect, retroviral, delivery. Gene expression persisted for at least twenty weeks under in vitro conditions. With regard to the in vivo studies, gene expression persisted within the clot and in some of the adjacent meniscal cells for at least three weeks in the lapine defect model. In the canine defect model, gene expression persisted within the transplanted, transduced meniscal cells for at least six weeks. Conclusions: It is possible to transfer genes to sites of meniscal damage and to express them locally within the lesion for several weeks. Clinical Relevance: Healing of the avascular portion of the meniscus may be improved by the transfer of genes encoding the appropriate growth factors. To our knowledge, the present report is the first to describe methods for transferring genes to the meniscus. When used in conjunction with the appropriate growth-factor genes, these techniques should help to provide the basis for potential alternative treatment options for meniscal lesions. Additional studies are needed to determine whether these techniques will lead to improved healing of meniscal defects in vivo