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➤ Posterior tibial slope (PTS) of ≥12° represents an important risk factor for both anterior cruciate ligament (ACL) injury and ACL reconstruction failure.➤ PTS measurements can significantly differ on the basis of the imaging modality and the measurement technique used. PTS should be measured on strictly lateral radiographs, with a recommended proximal tibial length of 15 cm in the image. The PTS measurement can be made by placing 2 circles to define the proximal tibial axis, 1 just below the tibial tubercle and another 10 cm below it. PTS measurements are underestimated when made on magnetic resonance imaging and computed tomography.➤ Slope-reducing osteotomies can be performed using a (1) supratuberosity, (2) tubercle-reflecting transtuberosity, or (3) infratuberosity method. The correction target remains a topic of debate. Although it is controversial, some authors recommend overcorrecting the tibial slope slightly to a range of 4° to 6°. For instance, if the initial slope is 12°, a correction of 6° to 8° should be performed, given the target tibial slope of 4° to 6°.➤ Clinical outcomes following slope-reducing osteotomies have been favorable. However, potential complications, limited data with regard to the impact of slope-reducing osteotomies on osteoarthritis, and uncertainty with regard to the effects on the patellofemoral joint are notable concerns.➤ Patients with complex deformities may need biplanar osteotomies to comprehensively address the condition., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/I124 )., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Knee osteotomies are essential orthopedic procedures with the ability to preserve the joint and correct ligament instabilities. Literature supports the correlation between lower limb malalignment and outcomes after knee ligament reconstruction and cartilage procedures. Concepts such as joint line obliquity, posterior tibial slope angle, and intra-articular deformity correction are integral components of both preoperative planning and postoperative evaluations. The concept of preserving and/or restoring joint line congruence during simultaneous correction of varus or valgus deformity can be achieved through several different approaches. With advancements in osteotomy research and surgical planning technology, the surgical decision-making has increased in complexity. Based upon a patient's specific deformity, decisions need to be made whether to perform a single-level (proximal tibia or distal femur) versus double-level (both proximal tibia and distal femur) osteotomy, and whether to correct deformity in a single plane (coronal or sagittal) or perform a biplanar osteotomy, correcting two of the malalignments in either coronal, sagittal, or axial planes. Osteotomy procedures prioritize safety, reproducibility, precision, and meticulous planning. Equally important is the proactive management of possible complications and the implementation of preventive strategies for complications such as hinge fractures and unintentional changes to alignment in other planes. This review navigates the intricate landscape of lower limb alignment, commencing with foundational definitions and rationale for performing osteotomies, progressing through the planning phase, and addressing the critical aspect of complication prevention, all while looking ahead to anticipate future advancements in this field. However, rotational osteotomies and tibial tubercle osteotomies in isolation or as an adjunct procedure are beyond the scope of this review., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Matthieu Ollivier reports a relationship with Newclip Technics that includes: consulting or advisory. Matthieu Ollivier reports a relationship with Stryker that includes: consulting or advisory. Matthieu Ollivier reports a relationship with Zimmer Inc that includes: consulting or advisory. Volker Musahl reports a relationship with Smith and Nephew Inc that includes: consulting or advisory, funding grants, and speaking and lecture fees. Volker Musahl reports a relationship with Arthrex Inc that includes: funding grants. Volker Musahl reports a relationship with DePuy Synthes that includes: funding grants. Volker Musahl reports a relationship with Newclip Technics that includes: consulting or advisory. Volker Musahl reports a relationship with International Society of Arthroscopy Knee Surgery and Orthopaedic Sports Medicine that includes board membership. Volker Musahl has patent #9,949,684 issued to U.S. Patent. Matthieu Ollivier reports royalties from Newclip, Stryker, and Zimmer. Volker Musahl is deputy editor-in-chief of Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA). If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Recent advances in surgical techniques and planning for knee-based osteotomies have led to improvements in addressing lower extremity malalignment. Part 1 of this review presented the biomechanical and clinical rationale of osteotomies, emphasizing the importance of osteotomies for restoring normal knee kinematics. In Part 2 of this review, indications, surgical technique and outcomes of osteotomies to correct coronal, sagittal and axial plane deformities will be examined. Traditional high tibial and distal femoral osteotomies will be discussed in addition to more recent advanced techniques including biplanar corrections and double-level osteotomies, as well as slope-correcting osteotomies. Patient-specific instrumentation and its use in more complex corrections will also be addressed., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Matthieu Ollivier reports a relationship with Newclip Technics that includes: consulting or advisory. Matthieu Ollivier reports a relationship with Stryker that includes: consulting or advisory. Matthieu Ollivier reports a relationship with Zimmer Inc that includes: consulting or advisory. Al Getgood is a board or committee member for ACL Study Group and the International Society of Arthroscopy, Knee Surgery, and Orthopaedic Sports Medicine (ISAKOS). Alan Getgood is a member of the editorial board of the American Journal of Sports Medicine and Knee Surgery, Sports Traumatology, Arthroscopy. Al Getgood reports research support from Aesculap/B. Braun, Arthrex, Inc, DePuy, Johnson & Johnson Company, Eupraxia Pharmaceuticals Inc, Musculoskeletal Transplant Foundation, and Ossur. Al Getgood has received IP royalties from Graymont Inc and are involved in companies like LinkX Robotics, Ostesys Robotics, Precision OS, and Spring Loaded Technologies Inc, with stock or stock options. Al Getgood also has also received paid consulting/presenting/speaking fees and research support from Smith & Nephew. Volker Musahl reports a relationship with Smith and Nephew Inc that includes: consulting or advisory, funding grants, and speaking and lecture fees. Volker Musahl reports a relationship with Arthrex Inc that includes: funding grants. Volker Musahl reports a relationship with DePuy Synthes that includes: funding grants. Volker Musahl reports a relationship with Newclip Technics that includes: consulting or advisory. Volker Musahl reports a relationship with International Society of Arthroscopy Knee Surgery and Orthopaedic Sports Medicine that includes: board membership. Volker Musahl has patent #9,949,684 issued to U.S. Patent. Matthieu Ollivier reports royalties from Newclip, Stryker and Zimmer. Volker Musahl is deputy editor-in-chief of Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA). If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Coronal and sagittal plane knee malalignments have been shown to increase the forces on anterior cruciate ligament (ACL) grafts after ACL reconstruction (ACLR). Studies have shown the benefit of high tibial osteotomy to address coronal and sagittal imbalance in revision ACLR. The purpose of this article is to further describe the use of osteotomy by reviewing preoperative planning, indications, techniques, and outcomes of high tibial opening and closing wedge as well as anterior tibial closing wedge osteotomies in the setting of ACLR., Competing Interests: Disclosure The authors have no relevant commercial or financial conflicts of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: The aim of this study was to investigate whether the whole tibial spine volume and femoral intercondylar notch volume are risk factors for anterior cruciate ligament (ACL) injury. The hypothesis was that the whole tibial spine volume and femoral notch volume would be smaller in athletes who sustained ACL injury than in athletes with no history of ACL injury., Methods: Computed tomography scans of both knees were acquired and three-dimensional bone models were created using Mimics to measure whole tibial spine volume and femoral notch volume. Tibial spine volume, femoral notch volume and each of these volumes normalised by tibial plateau area were compared between the ACL-injured and the ACL-intact group., Results: Fifty-one athletes undergoing unilateral anatomical ACL reconstruction (17 female, 34 male: average age 22.0 ± 7.5) and 19 healthy collegiate athletes with no previous knee injury (eight female, 11 male: average age 20.1 ± 1.3) were included in this study. The whole tibial spine volume in the ACL-injured group (2.1 ± 0.5 cm 3 ) was 20.7% smaller than in the ACL-intact group (2.7 ± 0.7 cm 3 ) (p = 0.005). No differences were observed between the femoral notch volume in the ACL-injured group (9.5 ± 2.1 cm 3 ) and the ACL-intact group (8.7 ± 2.7 cm 3 ) (n.s.)., Conclusions: The main finding of this study was that the whole tibial spine volume of the ACL-injured group was smaller than the ACL-intact group. A small tibial spine volume can be added to the list of anatomical risk factors that may predispose athletes to ACL injury., Level of Evidence: Level Ⅲ., (© 2024 European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

High tibial osteotomy is a powerful technique to treat symptomatic varus deformity of the knee and is successful when properly indicated and performed. Indications include varus deformity with medial compartment osteoarthritis, cartilage or meniscus pathology. Several techniques exist to correct symptomatic varus malalignment along with concomitant procedures to restore cartilage or meniscus injuries. Evidence supporting high tibial osteotomy for symptomatic medial compartment pathology exists, which provides a durable solution for joint preservation. This review will discuss the indications, techniques, and outcomes for high tibial osteotomies used in the treatment of symptomatic varus deformity of the knee., (Copyright © 2021 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Background: Bone bruises are frequently found on magnetic resonance imaging (MRI) after anterior cruciate ligament (ACL) injury and have been related to the force associated with the trauma. Yet, little is known about the bone bruise distribution pattern of skeletally immature (SI) patients, as the presence of an open physis may play a role in energy dissipation given its unique structure., Purpose: To describe and compare the location and distribution of tibial and femoral bone bruises, observed on MRI, between 2 groups of ACL-injured knees: the first group with an open physis and the second with a closed physis. Additionally, based on the bone bruise distribution pattern, the secondary aim of the study was to propose a new classification of bone bruise in SI patients., Study Design: Cross-sectional study; Level of evidence, 3., Methods: A retrospective review was conducted to identify all cases of primary ACL tears in patients ≤16 years old, with MRI within 6 weeks of injury between January 2012 and December 2016. Overall, 106 patients were identified: 53 with open physis (skeletally immature [SI] group) and 53 with closed physis as control (skeletally mature [SM] group). MRI scans were reviewed to assess for the presence and location of bone bruises. Longitudinal bone bruise distribution was described as epiphyseal and metaphyseal in both femur and tibia. The proposed classification for tibia and femur has 2 parts: the location of the bone bruise in the (I) lateral, (II) medial, or (III) medial and lateral parts of the bone; and if the bone bruise (a) does not or (b) does cross the physis. For the tibia, if the bone bruise is also present in the central portion, a letter C is added., Results: The SI group had significantly fewer bone bruises cross the physis and extend into the metaphysis than did the SM group for both the tibia (25% vs 85%, respectively; P < .0001) and the femur (4% vs 42%; P < .0001). The most common patterns observed in the SI group were type IIICa in the tibia (medial/lateral and central, not extending into the metaphysis: 42%) and type Ia in the femur (lateral, not extending into the metaphysis: 59%)., Conclusion: The data from this study shows that patients with an open physis at the occurrence of an acute ACL rupture have unique bone bruise patterns as compared with those with a closed physis. In the SI patients, the bone bruise pattern is significantly less frequently observed in the tibial and femoral metaphysis.

The purpose of this report was to describe the injury mechanism, surgical findings, and outcomes in a 21-year-old professional female football player who presented with a complete anterior cruciate ligament (ACL) rupture and Segond fracture. Interview and video analysis were performed to elicit the injury mechanism. Clinical examination and imaging revealed a complete ACL tear, Segond fracture, lateral meniscus tear, MCL sprain, and posterolateral corner sprain. Examination under anaesthesia revealed Grade 2 pivot shift and varus/valgus instability. Surgical examination revealed attachment of the posterior fibres of the iliotibial band and the lateral capsule to the Segond fragment. The fracture was reduced with suture fixation, and an anatomic ACL reconstruction was performed. Follow-up demonstrated rotatory and anterior tibial translation stability, and imaging at 7 months post-operatively revealed no movement and continued osseous integration of the Segond fragment. Level of evidence V.

Purpose: To propose a classification system for the shape of the tibial insertion site (TIS) of the anterior cruciate ligament (ACL) and to demonstrate the intra- and inter-rater agreement of this system. Due to variation in shape and size, different surgical approaches may be feasible to improve reconstruction of the TIS., Methods: One hundred patients with a mean age of 26 ± 11 years were included. The ACL was cut arthroscopically at the base of the tibial insertion site. Arthroscopic images were taken from the lateral and medial portal. Images were de-identified and duplicated. Two blinded observers classified the tibial insertion site according to a classification system., Results: The tibial insertion site was classified as type I (elliptical) in 51 knees (51 %), type II (triangular) in 33 knees (33 %) and type III (C-shaped) in 16 knees (16 %). There was good agreement between raters when viewing the insertion site from the lateral portal (κ = 0.65) as well as from the medial portal (κ = 0.66). Intra-rater reliability was good to excellent. Agreement in the description of the insertion site between the medial and lateral portals was good for rater 1 and good for rater 2 (κ = 0.74 and 0.77, respectively)., Conclusion: There is variation in the shape of the ACL TIS. The classification system is a repeatable and reliable tool to summarize the shape of the TIS using three common patterns. For clinical relevance, different shapes may require different types of reconstruction to ensure proper footprint restoration. Consideration of the individual TIS shape is required to prevent iatrogenic damage of adjacent structures like the menisci., Level of Evidence: III.

Purpose: To determine the distribution of different sizes of the area of the tibial insertion site among the population and to evaluate whether preoperative MRI measurements correlate with intraoperative findings to enable preoperative planning of the required graft size to cover the tibial insertion site sufficiently. The hypothesis was that the area of the tibial insertion site varies among individuals and that there is good agreement between MRI and intraoperative measurements., Methods: Intraoperative measurements of the tibial insertion site were taken on 117 patients. Three measurements were taken in each plane building a grid to cover the tibial insertion site as closely as possible. The mean of the three measurements in each plane was used for determination of the area. Two orthopaedic surgeons, who were blinded to the intraoperative measurements, took magnetic resonance imaging (MRI) measurements of the area of the tibial insertion site at two different time points., Results: The intraoperative measured mean area was 123.8 ± 21.5 mm 2 . The mean area was 132.8 ± 15.7 mm 2 (rater 1) and 136.7 ± 15.4 mm 2 (rater 2) when determined using MRI. The size of the area was approximately normally distributed. Inter-rater (0.89; 95 % CI 0.84, 0.92; p < 0.001) and intrarater reliability (rater 1: 0.97; 95 % CI 0.95, 0.98; p < 0.001; rater 2: 0.95; 95 % CI 0.92, 0.96; p < 0.001) demonstrated excellent test-retest reliability. There was good agreement between MRI and intraoperative measurement of tibial insertion site area (ICCs rater 1: 0.80; 95 % CI 0.71, 0.87; p < 0.001; rater 2: 0.87; 95 % CI 0.81, 0.91; p < 0.001)., Conclusion: The tibial insertion site varies in size and shape. Preoperative determination of the area using MRI is repeatable and enables planning of graft choice and size to optimally cover the tibial insertion site., Level of Evidence: III.

Purpose: This systematic review evaluates radiographic and clinical outcome reporting following navigated high tibial osteotomy (HTO). Conventional HTO was used as a control to compare outcomes and furthermore investigate the quality of evidence in studies reporting outcomes for navigated HTO. It was hypothesized that navigated HTO will show superior clinical and radiographic outcomes compared to conventional HTO., Methods: Two independent reviewers searched PubMed, Ovid (MEDLINE), EMBASE, and Cochrane databases for studies reporting outcomes following navigated HTO. Titles, abstracts, and full-text were screened in duplicate using an a priori inclusion and exclusion criteria. Descriptive statistics were calculated using Minitab ® statistical software. Methodological Index for Nonrandomized Studies (MINORS) and Cochrane Risk of Bias Scores were used to evaluate methodological quality., Results: Thirty-four studies which involved 2216 HTOs were analysed in this review, 1608 (72.6 %) navigated HTOs and 608 (27.4 %) conventional HTOs. The majority of studies were of level IV evidence (16). Clinical outcomes were reported in knee and function scores or range of motion comparisons. Postoperative clinical and functional scores were improved by navigated HTO although it is not demonstrated if there is significant improvement compared to conventional HTO. Most common clinical outcome score reported was Lysholm scores (6) which report postoperative scores of 87.8 (standard deviation 5.9) and 88.8 (standard deviation 5.9) for conventional and navigation-assisted HTO, respectively. Radiographic outcomes reported commonly were weight-bearing mechanical axis, coronal plane angle, and posterior tibial slope angle in the sagittal plane. Studies have shown HTO gives significant correction of mechanical alignment and navigated HTO produces significantly less change in posterior tibial slope postoperatively compared to conventional. The mean MINORS for the 17 non-comparative studies was 9/16, and 15/24 for the 14 non-randomized comparative studies., Conclusion: Navigation HTO results in improved mechanical axis alignment and demonstrates significantly better control over the tibial slope angle change postoperatively compared to conventional methods; however, these improvements have not yet been reflected in clinical outcome scores. Overall the studies report HTO does create significantly improved knee scores and functions compared to patients' preoperative ratings regardless of technique. Future studies on HTO outcomes need to focus on consistency of outcome reporting., Level of Evidence: IV.

Background: The purpose of this study was to examine (1) timelines for return to sport and work following high tibial osteotomy (HTO), and (2) whether patients return to sport and work at levels similar to preoperative levels., Methods: A systematic search was conducted across 3 databases (MEDLINE, Embase, and PubMed). Two reviewers independently screened the results for relevant articles. Data regarding patient demographics, indications, surgical technique, return to work and sport, and complication and failure rates were abstracted from eligible studies., Results: Nineteen studies were included, involving 1,189 patients (64% male, 21% female, 15% unspecified) and 1,224 knees. Mean age was 46.2 years (range, 16 to 80 years). Opening-wedge HTO was most commonly used, followed by closing-wedge HTO and hemicallotasis. Mean follow-up was 65.4 months (range, 8 to 253 months). Overall, 87.2% of patients returned to sport postoperatively, and 78.6% returned at an equal or greater level. Among competitive athletes, 54% returned to competition. Overall, 84.5% of patients returned to work postoperatively, and 65.5% returned at an equal or greater level. Approximately 90% of patients who returned to work or sport did so within 1 year. The complication rate was 5.8%, with infection being the most common complication; 7.0% of patients progressed to a total knee arthroplasty at a mean of 6.7 years (range, 0.8 to 15 years) following HTO., Conclusions: The majority of patients undergoing HTO return to sport and work, and most return within 1 year of the operation. Most patients return to sport at a level equal to or greater than the preoperative level. Approximately two-thirds of patients return to an equal or greater level of physical work., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence., (Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: There are conflicting reports regarding the role of osseous morphologic characteristics such as an increased tibial slope as associated with an anterior cruciate ligament (ACL) injury. Few studies have analyzed the role of a combination of osseous morphologic characteristics in matched case control studies. The aim of this study was to determine if there is an association between osseous morphologic characteristics and ACL injury in male college American-football players., Methods: Ninety male U.S. National Collegiate Athletic Association (NCAA) Division-I college football players who underwent magnetic resonance imaging (MRI) for a knee injury between 2005 and 2014 were included. Subjects with an ACL injury (ACL-injured group) were matched for age, height, weight, and body mass index to subjects without an ACL injury (control group). Several osseous morphologic characteristics including medial and lateral condylar width, medial and lateral plateau width, notch width, bicondylar width, notch width index, and medial and lateral tibial slopes were measured and were compared between groups. Conditional logistic regression was used to analyze the data. Significance was set at p < 0.05., Results: According to univariable analysis, a narrower lateral femoral condyle (odds ratio, 0.82 [95% confidence interval (95% CI), 0.68 to 0.97]), increased medial tibial plateau slope (odds ratio, 1.42 [95% CI, 1.09 to 1.85]), and increased lateral tibial plateau slope (odds ratio, 1.43 [95% CI, 1.15 to 1.78]) were significantly associated with ACL injury. Multivariable analysis revealed that increased lateral tibial slope (odds ratio, 1.32 [95% CI, 1.03 to 1.70]) was the sole independent predictor of ACL injury., Conclusions: Based on this study, osseous morphology, specifically increased lateral tibial slope, is associated with ACL injury in male college football players. These data might help to improve prevention strategies to lower ACL injury., Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence., (Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.)

Purpose: Recently, different measurement systems have been developed to quantitatively measure the pivot shift in vivo. These systems lack validation and a large inter-examiner variability for the manually performed pivot shift test exists. The purpose of this study was to perform objective measurements of the pivot shift using three different measurement devices and to examine the correlation of the measurements with clinical grading of the pivot shift., Methods: A cadaver knee on a whole lower body specimen was prepared to display a high-grade pivot shift. The pivot shift tests were performed three times by 12 blinded expert surgeons using their preferred technique. Simultaneous data samplings were recorded using three different measurement devices: (1) electromagnetic tracking system using bone-attached and skin-fixed sensors, respectively, (2) triaxial accelerometer system, and (3) simple image analysis. The surgeons graded the knee clinically using pivot shift grades I-III. Correlations were calculated using the Spearman's rank correlation coefficient., Results: The expert surgeons average clinical grading was 2.3 (SD ± 0.5). Clinical grading displayed best correlation with the acceleration of reduction as measured by electromagnetic tracking system with bone-attached sensors (r = 0.67, P < 0.05). Similar correlation coefficient was found for the acceleration of reduction (r = 0.58, P = 0.05) and the "jerk" component of acceleration (r = 0.61, P < 0.05) measured by means of the triaxial accelerometer system., Conclusion: The pivot shift can be quantified by several in vivo measurement devices. Best correlation with clinical grading was found with tibial acceleration parameters. Future studies will have to analyze how quantitative parameters can be utilized to standardize clinical grading of the pivot shift., Level of Evidence: Diagnostic study, Level II.

Purpose: The purpose of this study was to objectively evaluate the anatomic and biomechanical outcomes of anterior cruciate ligament (ACL) reconstruction with transtibial versus anteromedial portal drilling of the femoral tunnel., Methods: Ten human cadaveric knees (5 matched pairs) without ligament injury or pre-existing arthritis underwent ACL reconstruction by either a transtibial or anteromedial portal technique. A medial arthrotomy was created in all cases before reconstruction to determine the center of the native ACL tibial and femoral footprints. A 10-mm tibial tunnel directed toward the center of the tibial footprint was prepared in an identical fashion, starting at the anterior border of the medial collateral ligament in all cases. For transtibial femoral socket preparation (n = 5), a guidewire was placed as close to the center of the femoral footprint as possible. With anteromedial portal reconstruction (n = 5), the guidewire was positioned centrally in the femoral footprint and the tunnel drilled through the medial portal in hyperflexion. An identical graft was fixed and tensioned, and knee stability was assessed with the following standardized examinations: (1) anterior drawer, (2) Lachman, (3) maximal internal rotation at 30°, (4) manual pivot shift, and (5) instrumented pivot shift. Distance from the femoral guidewire to the center of the femoral footprint and dimensions of the tibial tunnel intra-articular aperture were measured for all specimens. Statistical analysis was completed with a repeated-measures analysis of variance and Tukey multiple comparisons test with P ≤ .05 defined as significant., Results: The anteromedial portal ACL reconstruction controlled tibial translation significantly more than the transtibial reconstruction with anterior drawer, Lachman, and pivot-shift examinations of knee stability (P ≤ .05). Anteromedial portal ACL reconstruction restored the Lachman and anterior drawer examinations to those of the intact condition and constrained translation with the manual and instrumented pivot-shift examinations more than the native ACL (P ≤ .05). Despite optimal guidewire positioning, the transtibial technique resulted in a mean position 1.94 mm anterior and 3.26 mm superior to the center of the femoral footprint. The guidewire was positioned at the center of the femoral footprint through the anteromedial portal in all cases. The tibial tunnel intra-articular aperture was 38% larger in the anteroposterior dimension with the transtibial versus anteromedial portal technique (mean, 14.9 mm v 10.8 mm; P ≤ .05)., Conclusions: The anteromedial portal drilling technique allows for accurate positioning of the femoral socket in the center of the native footprint, resulting in secondary improvement in time-zero control of tibial translation with Lachman and pivot-shift testing compared with conventional transtibial ACL reconstruction. This technique respects the native ACL anatomy but cannot restore it with a single-bundle ACL reconstruction. Eccentric, posterolateral positioning of the guidewire in the tibial tunnel with the transtibial technique results in iatrogenic re-reaming of the tibial tunnel and significant intra-articular aperture expansion., Clinical Relevance: Anteromedial portal drilling of the femoral socket may allow for improved restoration of anatomy and stability with ACL reconstruction compared with conventional transtibial drilling techniques., (Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: Minimal attention has been directed toward tibial tunnel position and the native tibial anterior cruciate ligament (ACL) footprint., Purpose: To evaluate the effect of tibial tunnel position on restoration of knee kinematics and stability after ACL reconstruction., Study Design: Controlled laboratory study., Methods: Ten paired cadaveric knees were subjected to biomechanical testing (standardized Lachman and mechanized pivot-shift examination). With each maneuver, a computer-assisted navigation system recorded the 3-dimensional motion path of a tracked point at the center of the tibia, medial tibial plateau, and lateral tibial plateau. The testing protocol consisted of evaluation in the intact state and after complete ACL transection, after ACL transection with bilateral meniscectomy, and after ACL reconstruction using 3 tibial tunnel positions--over the top (OTT), anterior footprint (AT), and posterior footprint (PT)--with a standard femoral socket placed in the center of the femoral footprint. Repeated-measures analysis of variance with a post hoc Tukey test compared measured translations with each condition., Results: A significant difference in anterior translation was seen with Lachman examination between the ACL-deficient condition and both the OTT and AT reconstructions, but no significant difference was observed between the ACL-deficient and PT reconstruction. The OTT and AT constructs were significantly better in limiting anterior translation of the lateral compartment compared with the PT ACL reconstruction during a pivot-shift maneuver in the ACL- and meniscal-deficient knee. However, anteriorizing the tibial position was accompanied by a correspondingly greater risk and magnitude of graft impingement in extension., Clinical Relevance: The OTT and anterior tibial tunnel positions better control the Lachman and the pivot shift compared with an ACL graft placed in the posterior aspect of the tibial footprint. However, an anterior tibial tunnel position must be balanced against an increased risk and magnitude of graft impingement in extension.

The purpose of this study was to correlate clinical pivot shift grading with femoral condyle size as measured on pre-operative magnet resonance imaging (MRI) of patients with anterior cruciate ligament (ACL) injury. Forty-nine consecutive patients for anterior cruciate ligament (ACL) surgery were examined under anesthesia. The pivot shift was graded according to Galway et al. and MacIntosh et al. by a single observer. The grade of pivot shift, Lachman, and collateral laxity was recorded. Intraoperative findings of injury patterns to the ACL and other soft tissue structures were recorded. The anterior-posterior (AP) and medial-lateral (ML) diameter of femoral condyles and tibial plateaus were measured on pre-operative MRI. Patients were grouped into a grade 1 pivot shift group and a grade 2 pivot shift group. ANOVA and independent t tests were used to compare bony dimensions between grade 1 and 2 pivot shifts and by sex. Significance was set at P < 0.05. Twenty-seven patients had a grade 1 pivot shift and 22 a grade 2 pivot shift. Associated pathology was present in 11/27 patients (41%) with a grade 1 pivot shift and 21/22 patients (95%) with a grade 2 pivot shift. The ML diameter of the lateral tibial plateau was significantly smaller in patients with a grade 2 pivot shift (35.5 +/- 3.7 mm) compared to patients with a grade 1 pivot shift (30.3 +/- 3.2 mm; P < 0.05). No difference was detected for any of the other measurements taken (NS). When analyzed by sex this difference existed in women (group I: 31.1 +/- 3.2, group II: 28.8 +/- 2.0; P < 0.05) but not in men (group I: 34.1 +/- 3.7, group II: 33.1 +/- 3.1; NS). All morphologic measurements were larger in men (P < 0.05). A smaller (ML) lateral tibial plateau diameter may contribute to a patient's higher-grade pivot shift. When analyzed by sex this was true for women but not for men. There are other factors contributing to the magnitude of the pivot shift, such as concomitant generalized laxity, injury to the knee joint capsule, and size/or injury of other soft tissue structures that were not analyzed in this study.

Recurrent rotational instability has been identified as a potential source of failure of anterior cruciate ligament (ACL) reconstructions. The aim of the study was to assess whether knee kinematics in the horizontal configuration more closely resemble the intact knee when compared with other single-bundle configurations. Using the Praxim computer navigation system, ACL reconstructions were performed with tibialis anterior grafts in six fresh-frozen whole lower extremity cadaver specimens (12 knees). In each knee, all four reconstruction configurations: conventional (PL tibia to AM femur), anteromedial (AM), posterolateral (PL), and horizontal (AM tibia to PL femur) were performed. Standardized Lachman and pivot shift examinations were performed. For all graft positions during the pivot shift, decreases in the amount of ATT were observed compared with the ACL-deficient state. The knees with grafts placed in the anterior tibial footprint (AM and horizontal) had less ATT with the Lachman and pivot shift maneuvers than knees with grafts placed in the posterior tibial footprint (PL and conventional). A significant difference in depth of impingement was noted only between the AM position and the PL position. Single-bundle ACL reconstructions using graft placement within the anterior footprint on the tibia may reduce rotational instability when compared with more vertical configurations.

Transtibial single bundle anterior cruciate ligament (ACL) reconstruction has been the gold standard for several years. This technique often fails to restore native ACL femoral origin and tibial insertion anatomy of the ACL. Recently, there is a strong trend towards a more anatomical approach in single and double bundle ACL reconstruction. Using the anatomic double bundle structure of the ACL as a principle, the entirety of both tibial insertion and femoral origin of both bundles, the posterolateral and anteromedial, may be restored. Reflected by recent publications over the past two years, there is an increasing interest in the anatomy of the ACL. In the current study, a PubMed literature search was performed looking for measurements of the ACL femoral origin and tibial insertion. These studies show a large variability in the size and the anatomy of the femoral origin and tibial ACL insertion using different methods and specimens. The diversity of reported measurements makes clinical application of these data difficult at best. Thus, it is of paramount importance to understand the individual variations in size and shape of the ACL femoral origin and tibial ACL insertion. This study is a systematic review of the morphology of the ACL femoral origin and tibial insertion as reported in the literature.

Proper alignment of the mechanical axis of the lower limb is the principal goal of a high tibial osteotomy. A well-accepted and relevant technical specification is the coronal plane lower-limb alignment. Target values for coronal plane alignment after high tibial osteotomy include 2 degrees of overcorrection, while tolerances for this specification have been established as 2 degrees to 4 degrees. However, the role of axial plane and sagittal plane realignment after high tibial osteotomy is poorly understood; consequently, targets and tolerance for this technical specification remain undefined. This article reviews the literature concerning the reliability and precision of navigation in monitoring the clinically relevant specification of lower-limb alignment in high tibial osteotomy. We conclude that image-free navigation registration may be clinically useful for intraoperative monitoring of the coronal plane only. Only fair and poor results for the axial and sagittal planes can be obtained by image-free navigation systems. In the future, combined image-based data, such as those from radiographs, magnetic resonance imaging, and gait analysis, may be used to help to improve the accuracy and reproducibility of quantitative intraoperative monitoring of lower-limb alignment.