Outside-in Research Articles

Comparison of the Functional Outcomes of Arthroscopic Anterior Cruciate Ligament Reconstruction through the All-inside and Outside-in Techniques: A Double-Blinded Randomized Controlled Trial.

Objective To compare the functional outcomes of anterior cruciate ligament (ACL) reconstruction with hamstring autograft (HA) through the all-inside (AI) technique with adjustable-loop cortical Endobutton (Smith & Nephew, Watford, Hertfordshire, England) on the sides of the femur and tibia and through the outside-in (OI) technique using an interference screw on the tibial side and a cortical Endobutton on the femoral side. Materials and Methods The present is a double-blinded randomized controlled trial (RCT) of 44 patients undergoing arthroscopic ACL reconstruction from February 2019 to February 2022 in a tertiary care hospital. As per computer-based randomization, the patients were distributed into two groups: the AI and OI groups. Both groups were evaluated for 12 months using the Visual Analog Scale (VAS), the Lysholm Knee Scoring Scale, and part I (pain score) and part II (function score) of the Knee Society Score (KSS). Results On postoperative day 2, the VAS score was significantly higher in the OI group ( p = 0.0001), but insignificant ( p = 0.807) at 6 weeks. At 3, 6, and 12 months of follow-up, the score on the Lysholm Knee Scoring Scale was significantly higher ( p = 0.001) in the AI group. At 6 months, both parts of the KSS showed a significant difference, with the AI group presenting a better outcome ( p = 0.04). However, at 12 months, the AI group presented a better score on part I of the KSS, but no differences were observed regarding part II. Conclusion In a follow-up of 12 months, the patients submitted to the AI technique presented better outcome scores and pain relief than those submitted to the OI technique.

Towards balancing efficiency and customer satisfaction in airplane boarding: An agent-based approach

The airplane boarding process, which can have a significant impact on a flight’s turnaround time, is often viewed by researchers and airlines primarily in terms of minimizing total boarding time (TBT). Airplane capacity, number of passengers on board, amount of luggage, and boarding strategy are common factors that affect TBT. However, besides operational efficiency, airlines are also concerned with customer satisfaction, which affects customer loyalty and financial return. One factor that influences passenger experience is the individual boarding time (IBT), here defined by the time passengers stand inside the cabin. Considering these two aspects, an agent-based model is presented that compares the performance of three alternative mainstream boarding strategies in a 132-seat and a 160-seat single-aisle commercial airplane. An important characteristic of the model that differentiates it from previous work is that overhead bins have a physical limitation, which could lead to an increase in aisle interferences on full flights as passengers take longer to find a place for their carry-on luggage. Another important contribution is the analysis of how passenger seat location affects IBT. Our results show that outside-in (OI) produces shorter TBT than random and back-to-front boarding, and also shorter IBT and much shorter maximum IBT than BTF, particularly for passengers seated in the middle of the airplane. This suggests that among the three most popular boarding strategies used by airlines across the world, OI is the best when it comes to balancing airplane boarding efficiency with individual customer satisfaction.

Anteromedial Portal Technique, but Not Outside-in Technique, Is Superior to Standard Transtibial Technique in Knee Stability and Functional Recovery After Anterior Cruciate Ligament Reconstruction: A Network Meta-analysis

To compare the postoperative outcomes of 4 different femoral drilling techniques in anterior cruciate ligament reconstruction. Three databases were searched for randomized controlled trials comparing any 2 or more of the following femoral drilling techniques in anterior cruciate ligament reconstruction: standard transtibial (sTT), anteromedial portal (AMP), outside-in (OI), or modified transtibial (mTT) technique. A Bayesian network meta-analysis was performed to assess postoperative stability and functional recovery in terms of the side-to-side difference (measured by arthrometry), Lachman test, pivot-shift test, International Knee Documentation Committee subjective and objective scores, Lysholm score, and Tegner score. The Fisher exact probability test and χ2 test were used to compare the incidences of infection and graft rupture, respectively. We included 20 randomized controlled trials involving 1,515 patients. The AMP technique showed a lower side-to-side difference (standardized mean difference, -0.33; 95% credible interval [CrI], -0.53 to -0.12), higher negative rate on the pivot-shift test (odds ratio, 2.19; 95% CrI, 1.38 to 3.44), and higher International Knee Documentation Committee objective score (odds ratio, 3.13; 95% CrI, 1.42 to 7.82) than the sTT technique. However, knee stability and functional outcomes did not differ significantly between the OI and sTT techniques. Safety outcomes of the mTT technique were unavailable. The incidence of graft rupture was 5.20% for the OI technique, 2.27% for the AMP technique, and 1.51% for the sTT technique. The OI technique had a significantly higher incidence of graft rupture than the sTT technique (χ2= 4.421, P= .035). No significant difference in the incidence of infection was found between the sTT, AMP, and OI techniques (P= .281). The AMP technique, but not the OI technique, was superior to the sTT technique in knee stability and functional recovery. The OI technique had a higher incidence of graft rupture than the sTT technique. There was no significant difference between the AMP and OI techniques or between the mTT technique and any other femoral drilling technique. Level II, meta-analysis of Level I and II studies.

Integration of outside-in and inside-out entrepreneurial marketing capabilities, marketing agility and resources for entrepreneurial firm performance

PurposeThe resource-based view (RBV) emphasises the importance of resources for firm performance. However, recent research argues that the focus on firm performance should also be based on inside-out (IO) and outside-in (OI) capabilities. Specifically, we study the importance of resources on product development (an IO) and market driving (an OI) entrepreneurial marketing capabilities on entrepreneurial firm performance in an emerging market. The study further investigates the moderating effects of marketing agility on the relationship between resources and capabilities.Design/methodology/approachThe study is based on survey data of a multi-industry sample of 102 entrepreneurial firms in Pakistan.FindingsThe results show that marketing agility moderates the relationship between resource-mix flexibility on product development and market driving capabilities, but it only positively moderates the relationship between resource-mix inimitability and product development capability. Marketing driving and product development capabilities play a role as parallel mediators between resources and firm performance.Originality/valueThe study lies at the intersection of marketing and entrepreneurship literature by (1) providing a nuanced understanding of marketing agility as a boundary spanning factor for IO and OI entrepreneurial marketing capabilities; (2) integrating the resource types and product development from IO and market-driving from OI capabilities perspectives; (3) identifying the effects of IO and OI on firm performance providing guidance for entrepreneurs seeking improved firm performance.

Outside-in technique versus inside-out semitendinosus graft harvest technique in ACLR: a randomised control trial

BackgroundParaesthesia after hamstring graft harvest is a ubiquitous complication in the early post-operative period, and its correlation with vertical versus horizontal skin incision are well documented. The purpose of the study is to evaluate the incidence and extent/area of sensory loss of saphenous nerve branches occurring with the outside-in (OI) versus inside-out technique (IO) of semitendinosus graft harvest from the sartorius fascia and to determine a better method of graft harvest.MethodsSixty patients who underwent isolated semitendinosus graft harvest during anterior cruciate ligament reconstruction (ACLR) between 2016 and 2017. Patients were randomised into two groups depending on the graft harvest technique: 30 in the OI group and 30 in the IO group. The area of sensory loss was mapped on the patients’ skin using tactile feedback from the patients at each follow-up (10 days, 1 month, 3 months, 6 months and 1 year). Then, the area of sensory changes for the infrapatellar branch (IPBSN) and sartorial branch (SBSN) of the saphenous nerve, incision length, graft harvest duration, and graft length were analysed statistically between the groups.ResultsIn groups 1 and 2, 18/30 (60%) and 19/30 (63%) of patients, respectively, developed sensory changes, with no significant difference between the groups (p = 0.79). Isolated SBSN and IPBSN paraesthesia occurred in 2/60 (3%) and 19/60 (32%), respectively. Combined SBSN and IPBSN paraesthesia was present in 16/60 (27%) of patients. There was no significant difference in the area of the sensory deficit between OI and IO groups on the 10th post-operative day or at 1-month, 3-month or 1-year follow-up (p = 0.723, p = 0.308, p = 0.478, p = 0.128, respectively). However, at 6-month follow-up, the area of paraesthesia was significantly higher in the IO group (p = 0.009). The length of incision and duration of graft harvest was higher in the OI group than in the IO group (p = 0.002 and p = 0.007, respectively), and the total length of the graft was greater in the IO group (p = 0.04).ConclusionIncidence is equally distributed, area of iatrogenic saphenous nerve injury gradually decreases, and recovery is seen in the majority of the patients in both graft harvest techniques. IO graft harvesting technique is better in terms of graft harvest time and cosmetics and yields longer graft; however, area of paraesthesia, though not significant, was two-fold higher than the OI technique at 1-year follow-up.Clinical relevanceIO graft harvest technique would enable the surgeon to adopt quicker graft harvest, smaller surgical scar and lengthier graft than the OI technique.Level of evidenceTherapeutic randomised controlled prospective study, Level II.

Influence of Graft Bending Angle on Femoral Tunnel Widening After Double-Bundle ACL Reconstruction: Comparison of Transportal and Outside-In Techniques.

Background:Previous studies have suggested that increased mechanical stress due to acute graft bending angle (GBA) is associated with tunnel widening and graft failure after anterior cruciate ligament (ACL) reconstruction. Few studies have compared the GBA between the outside-in (OI) and the transportal (TP) techniques.Purpose:To evaluate the influence of GBA on clinical outcomes and tunnel widening after ACL reconstruction with OI versus TP technique.Study Design:Cohort study; Level of evidence, 3.Methods:Included in the study were 56 patients who underwent double-bundle ACL reconstruction (n = 28 in the OI group and n = 28 in the TP group). Clinical outcomes (Lysholm, International Knee Documentation Committee, Tegner score, and knee laxity) 1 year postoperatively were evaluated. Computed tomography scans at 5 days and 1 year postoperatively were used for imaging measurements, and the femoral tunnel was divided into the proximal third, middle, and aperture sections. The GBA and cross-sectional area (CSA) were measured using image analysis software and were compared between groups. A correlation analysis was performed to determine if the GBA affected clinical outcomes or tunnel widening.Results:No significant difference was observed in clinical outcomes between the groups. The GBA of both the anteromedial (AM) and posterolateral bundles were more acute in the OI group compared with the TP group (P < .05). The CSA at the AM tunnel aperture increased significantly in the OI group (84.2% ± 64.3%) compared with the TP group (51.4% ± 36.7%) (P = .04). However, there were no differences in the other sections. In the Pearson correlation test, GBA was not correlated with tunnel widening or clinical outcomes.Conclusion:Regardless of technique, the GBA did not have a significant influence on tunnel widening or clinical outcomes. Considering a wider AM tunnel aperture, a more proximal and posterior AM tunnel position might be appropriate with the OI technique.

Progress of different methods for femoral tunnel positioning in anterior cruciate ligament reconstruction

To systematically review the progress of different methods for femoral tunnel positioning in anterior cruciate ligament (ACL) reconstruction and provide a clinical reference for treatment of ACL rupture. The literature about the femoral tunnel positioning in ACL reconstruction was widely reviewed. The advantages and disadvantages and the clinical results of each method were summarized. Currently in ACL reconstruction, methods for femoral tunnel positioning include transtibial technique (TT), anteromedial technique (AM), outside-in (OI), modified TT (mTT), and computer assisted surgery. There is no significant difference in the postoperative effectiveness between TT technique and AM technique. Compared with the TT technique, the OI technique has higher rotational stability of knee, but there is no significant difference in clinical results. The femoral tunnel located by mTT technique is closer to the anatomical placement than that of TT technique, but mTT technique is not effective for systematically anatomic femoral tunnel positioning, and further research is needed to prove its advantages. Different femoral tunnel positioning methods have their own advantages and disadvantages, and there is no definite evidence that one is superior than the rest.

The influence of the board of directors on outside-in strategy

Evidence suggests that focusing on the needs of the marketplace to create customer value and firm advantage, an outside-in (OI) approach to strategy, yields superior firm performance. However, despite the acknowledged advantage of an OI approach to strategy, it has not yet achieved widespread adoption by industry practitioners. Absent formal insight regarding how a firm-wide OI approach to strategy emerges, we introduce the premise that a firm-wide practice requires influence from those at the top of firm hierarchy, i.e., its Board of Directors. We posit that if the OI construct is both: (1) strategic rather than tactical in nature, and (2) enterprise-wide rather than function specific (e.g., marketing), then firm-wide adoption requires BOD acceptance, if not advocacy and leadership. We present 10 research propositions that describe how the board influences a firm-wide OI approach to strategy and provide specific implications for scholars from marketing and corporate governance as well as boards and chief marketing officers.

Outside-in box covering method and information dimension of Sierpinski networks

Self-similarity is a significant property for complex networks. Box coverage method and dimension calculation are vital tools to study the characteristic of complex networks. In this paper, we propose an outside-in (OSI) box covering method for the Sierpinski networks, and it is attested that this coverage algorithm is superior to CBB algorithm. In addition, we deduce the optimal box recurrence formula of weighted and unweighted networks theoretically, and the result is the same as that of the algorithm value. We also obtain the information dimension of weighted network, which verifies the validity and feasibility of our method.

Anteromedial Portal Double-Bundle Anterior Cruciate Ligament Reconstruction Yields Similar Outcomes to Non-AMP Femoral Drilling Double-Bundle Techniques: A Systematic Review of Comparative Studies.

Background:Biomechanical studies have shown double-bundle (DB) anterior cruciate ligament reconstruction (ACLR) to have increased anterior and rotational stability as compared with single-bundle ACLR. Various techniques exist to drill the femoral tunnel, such as anteromedial portal (AMP), outside-in (OI), and transtibial (TT) drilling. However, it is unclear whether one drilling technique is superior to others when a DB graft is used.Purpose:To systematically assess the outcomes and complications in patients undergoing DB ACLR through an AMP technique as compared with other femoral drilling techniques.Study Design:Systematic review; Level of evidence, 3.Methods:PubMed, Medline, and EMBASE databases were searched in April 2018. Nonrandomized studies were assessed with the MINORS (Methodological Index for Nonrandomized Studies), whereas randomized studies were assessed with the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system.Results:Ten studies comprising 722 patients satisfied the inclusion criteria. A total of 351 patients underwent DB ACLR with AMP drilling (mean ± SD age, 32.7 ± 4.7 years); 318 patients had DB ACLR with OI drilling (age, 31.9 ± 4.1 years); and 53 received a DB ACLR with TT drilling (age, 26.5 ± 2.0 years). Graft types used included hamstring autograft (74.1%; n = 247), tibialis anterior autograft (6.0%; n = 20) and unspecified grafts (19.8%; n = 66). No significant difference in postoperative Tegner and Lysholm scores was found between the AMP and OI groups postoperatively. The AMP group had a lower anterior and posterior graft bending angle as compared with the OI group. Four patients (1.1%) in the AMP group had graft reruptures, as compared with 9 reruptures (2.8%) in the OI group. There were no reports of rerupture in the TT group.Conclusion:DB AMP ACLR results in significantly improved functional outcome scores postoperatively. AMP techniques yield similar functional outcomes to OI ACLR. No direct comparison in functional outcomes scores were available between the AMP and TT techniques. Low overall complication and revision rates were observed for patients undergoing DB AMP ACLR and were found to be similar to those of other femoral drilling techniques. Owing to a steeper graft bending angle in patients undergoing OI or TT ACLR relative to AMP ACLR, patients treated with OI or TT femoral drilling may have increased strain placed on the graft. Based on the various limitations in the available literature, it is not currently possible to make a definite conclusion of whether AMP is superior to non-AMP techniques in the setting of DB ACLR.

Crafting strategy for international marketing: outside-in or inside-out?

PurposeDrawing on the resource-based view, dynamic capabilities and exploration literatures, the purpose of this paper is to simultaneously investigate the impact of outside-in (OI) and inside-out (IO) strategic approaches on international strategic performance.Design/methodology/approachA survey-based quantitative study was used. The final sample consisted of 202 internationally active SBUs of Israeli firms. Data were analyzed using structural equation modelling.FindingsOI approach to strategy enhances international performance more than IO does. OI is antecedent of exploratory marketing capabilities (MCs), while IO is antecedent of exploratory technological capabilities (TCs). The direct positive effect of exploratory MCs on performance is twice as strong as exploratory TCs are. Additionally, exploratory MCs positively impact performance through product adaptation.Practical implicationsTo enhance international performance, managers should devote attention to an OI approach by incorporating a market orientation with responsive flexibility. Managers should be aware that exploratory MCs are more important in an international context than exploratory TCs are. Stakeholders such as venture capitalists can use the OI–IO model to predict which international venture is more promising.Originality/valueThis paper contributes to the international marketing field by shedding light on the OI–IO debate, its transformation into exploratory capabilities and how it relates to the standardization–adaptation debate. New and broad OI–IO’s conceptualizations are developed and new viewpoints for understanding how international marketing should work and what motivates firms to adapt are offered. Overall, an OI–IO typology helps to bring order to an otherwise confusing conceptual landscape.

Variation in Graft Bending Angle During Range of Motion in Single-Bundle Posterior Cruciate Ligament Reconstruction: A 3-Dimensional Computed Tomography Analysis of 2 Techniques

To compare variations in femoral graft bending angle during range of motion (ROM) of the knee between inside-out (IO) and retro-socket outside-in (OI) techniques in posterior cruciate ligament (PCL) reconstruction using invivo 3-dimensional (3D) computed tomography analysis. Ten patients underwent PCL reconstruction by the IO technique (5 patients) or the retro-socket OI technique (5 patients) for suspensory femoral fixation. After PCL reconstruction, 3D computed tomography was performed in 0° extension and 90° flexion to reconstruct 3D femur and tibia bone models using Mimics software. Positions of femur and tibia at 30°, 45°, and 60° flexion were reproduced by determining the kinematic factors of anteroposterior translation, mediolateral translation, and internal-external rotation angle of each patient based on previously measured kinematic data. Variation in graft bending angle according to the flexion range of the knee was calculated by the difference in graft angulation measured at each flexion angle. The results were compared between the 2 techniques. There was significant difference in variation of femoral graft bending angle between IO and retro-socket OI techniques from 0° to 90° flexion of the knee (P= .008). Significant difference was also noticed at 30° to 45° (P= .008), 45° to 60° (P= .008), and 60° to 90° (P= .016) ROM of the knee between the 2 groups. The retro-socket OI technique resulted in less variation in femoral graft bending angle compared with the IO technique during knee ROM. We recommend the retro-socket OI technique for femoral tunnel placement to reduce the graft motion at the intra-articular femoral tunnel aperture. The retro-socket OI technique produces significantly less variation in femoral graft bending angle when compared with the IO technique. Such reduction in variation of femoral graft bending angle might be related to lower stress at the femoral tunnel aperture.

Comparison of clinical results, second look arthroscopic findings, and magnetic resonance imaging findings, between the transportal and outside-in techniques after double bundle anatomic anterior cruciate ligament reconstruction: A prospective randomized controlled trial with a minimum 2-year follow-up

Introduction Although image analysis has shown that the outside-in (OI) technique is associated with different femoral tunnel geometry than the transportal (TP) technique in anatomic anterior cruciate ligament (ACL) reconstruction, it is not known whether clinical results differ between the two techniques. We aimed to compare clinical results, second-look arthroscopic findings, and magnetic resonance imaging (MRI) findings between the TP and OI techniques in anatomic double-bundle (DB) ACL reconstruction. Methods From November 2010 to March 2013, 128 cases were enrolled in this study and were randomly assigned to either the TP group (64 cases) or the OI group (64 cases), and DB ACL reconstructions were performed. At the minimum 2-year follow-up (34.9 ± 10.9 months), 111 patients (86.7 %) were evaluated with multiple clinical scores and stability tests. Ninety-three knees were evaluated for graft continuity, graft tension, and synovialization by using second-look arthroscopy. Seventy-eight knees were evaluated on MRI for graft continuity, femoral graft tunnel healing, and graft signal/noise quotient (SNQ). Results There were no significant differences between the two groups in terms of clinical evaluation, with the exception of postoperative functional test of International Knee Documentation Committee (IKDC) objective score. The ratio of grade A and B on the functional test of the objective IKDC score was significantly larger for the OI group than the TP group (P = 0.005). The second-look arthroscopic findings were not significantly different between the two groups in either bundle (P > 0.05). In addition, MRI findings did not differ significantly between the two groups (P > 0.05). Conclusion With the exception of the functional test of IKDC objective score, clinical results, second-look arthroscopic findings, and MRI findings did not differ significantly between the OI and TP techniques for anatomic ACL reconstruction.

Comparison of Modified Transtibial and Outside-In Techniques in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction

To compare the bending angle of anterior cruciate ligament (ACL) graft at femoral tunnel, graft maturation, and tunnel positions and the clinical outcomes of the modified transtibial (mTT) and outside-in (OI) techniques. Patients who met the inclusion criteria were divided into the mTT group (n= 50) and the OI group (n= 50). Using 3-dimensional computed tomography (3-D CT), tunnel placement and femoral tunnel bending angle were analyzed. The 3.0-T magnetic resonance imaging (MRI) was used to assess the graft signal intensity (indicative of maturation) with signal/noise quotient (SNQ). Graft tension and synovialization were evaluated with second-look arthroscopy in all cases. Clinical and functional tests were completed at 36months of follow-up. When tunnel placements were analyzed using the quadrant method, no significant differences were found between the mTT group and the OI group. The femoral graft bending angle was reduced in the mTT group, and the total mean of SNQ values and mean SNQ values at the femoral intraosseous and proximal graft of the mTT group were significantly lower than in the OI group (P < .001), respectively. The femoral graft bending angle on the coronal and axial planes showed moderate-to-strong correlation with the SNQ values at the femoral intraosseous and proximal graft. Second-look arthroscopy revealed better synovialization in the mTT group than in the OI group (P= .040), with no significant difference in graft tension between the 2 groups (P= .328). Anatomic tunnel placements did not vary between the mTT group and the OI group. However, the mTT group had more benefits in femoral graft bending angle and showed higher graft maturity and better synovial coverage than the OI group, although there were no significant differences in clinicaloutcomes. The acute femoral graft bending angle might negatively affect the maturation of proximal graft. LEVELOF EVIDENCE: Level III, retrospective comparative study.

Better rotational control but similar outcomes with the outside-in versus the transtibial drilling technique for anterior cruciate ligament reconstruction: a systematic review of comparative trials.

This study was a systematic review comparing the clinical outcomes of using the transtibial (TT) versus the outside-in (OI) technique for anterior cruciate ligament (ACL) reconstruction. A comprehensive literature search was conducted using multiple databases, including Medline, Embase, and Cochrane. All databases were searched from the earliest records through August 2017 using the following Boolean operators: transtibial AND (outside-in OR out-in OR two incisions) AND anterior cruciate ligament. All prospective and retrospective controlled trials were retrieved that directly compared physical examination and knee function scores and patient-rated outcomes between the TT and OI techniques. Four prospective and three retrospective articles were identified by the search, and the findings suggested that the OI was superior to the TT technique for preparing the femoral tunnel based on the pivot shift test (p = 0.05). There was no statistically significant difference between the two treatment groups in International Knee Documentation Committee (IKDC) grades, IKDC scores, Lysholm scores, Tegner scores, or the Lachman test. No statistically significant differences were found in clinical functional results when comparing patients who underwent ACL reconstruction with the TT or OI techniques. However, the OI technique was found to be advantageous in conferring increased rotational stability as revealed by the pivot shift test. Additional studies with larger sample sizes are needed to make more precise conclusions. Therapeutic study (systematic review), Level III.

Comparison of Clinical Results, Second-Look Arthroscopic Findings, and MRI Findings Between the Transportal and Outside-In Techniques for Double-Bundle Anatomic Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized Controlled Trial With a Minimum 2-Year Follow-up

Background: Although image analysis has shown that the outside-in (OI) technique is associated with different femoral tunnel geometry than the transportal (TP) technique in anatomic anterior cruciate ligament (ACL) reconstruction, it is not known whether clinical results differ between the 2 techniques. Purpose: To compare clinical results, second-look arthroscopic findings, and magnetic resonance imaging (MRI) findings between the TP and OI techniques in anatomic double-bundle (DB) ACL reconstruction. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: From November 2010 to March 2013, 128 patients were enrolled in this study and were randomly assigned to either the TP group (64 patients) or the OI group (64 patients), and DB ACL reconstructions were performed. At the minimum 2-year follow-up (34.9 ± 10.9 months), 111 patients (86.7%) were evaluated with multiple clinical scores and stability tests (KT-2000 arthrometer, Lachman test, and pivot-shift test). Ninety-three knees were evaluated for graft continuity, graft tension, and synovialization by use of second-look arthroscopy. Seventy-eight knees were evaluated on MRI for graft continuity, femoral graft tunnel healing, and graft signal/noise quotient (SNQ). The primary outcome was KT-2000 arthrometer results. Results were compared between the TP and OI groups. Results: No significant differences were found between the 2 groups in terms of KT-2000 arthrometer results, which was the primary outcome, and other clinical results, with the exception of the postoperative functional test of International Knee Documentation Committee (IKDC) objective score. The ratio of grade A and B on the postoperative functional test of IKDC objective score was significantly larger for the OI group (51/58) than the TP group (36/53) (P = .005). The second-look arthroscopic findings were not significantly different between the 2 groups in either bundle (P > .05). In addition, MRI findings did not differ significantly between the 2 groups (P > .05). Conclusion: With the exception of the functional test of IKDC objective score, we found that clinical results, second-look arthroscopic findings, and MRI findings did not differ significantly between the OI and TP techniques for anatomic ACL reconstruction, although femoral tunnel geometries differed significantly between the 2 techniques.

Contact area between femoral tunnel and interference screw in anatomic rectangular tunnel ACL reconstruction: a comparison of outside-in and trans-portal inside-out techniques.

The purpose of this study was to compare the femoral tunnel length, the femoral graft bending angle at the femoral tunnel aperture, and the contact area between the femoral tunnel wall and an interference screw used for fixation in anatomic rectangular tunnel anterior cruciate ligament (ACL) reconstruction (ART ACLR). The study included 149 patients with primary ACL injury who underwent ART ACLR. Preoperatively, flexion angle of the index knee was checked under general anaesthesia. Those of less than 130° of passive flexion were assigned to the outside-in (OI) technique (78 patients), while the others to the trans-portal inside-out (TP) technique (71 patients). The patients underwent computed tomography with multiplanar reconstruction at 3-5weeks post-operatively. Femoral tunnel length, graft bending angle, and contact ratio between the IFS and femoral tunnel were assessed. P<0.05 was considered statistically significant. The femoral tunnel length in the OI technique was significantly longer than that in the TP technique (P<0.001). The femoral graft bending angle in the OI technique was significantly more acute than that in the TP technique (P<0.001). The contact ratio in the OI technique was significantly larger than that in the TP technique at every point in the femoral tunnel (P<0.001). The OI technique resulted in a more acute femoral graft bending angle, longer mean femoral tunnel length, and larger contact ratio than the TP technique after ART ACLR. Retrospective comparative study, Level III.

Posterior Cruciate Ligament Reconstruction with Retrograde Femoral Technique, Posterior Trans-septal Portal and Full Tibial Tunnel

Suspensory femoral graft fixation has been a popular and reliable method in anterior cruciate ligament (ACL) reconstruction. Some authors have introduced suspensory femoral fixation in posterior cruciate ligament (PCL) reconstruction using inside-out (IO) technique. The use of IO technique for femoral tunnel preparation could significantly sharpen the critical corner, which might result in graft failure. A retrograde drilling pin that recently has been popular in ACL reconstruction allows “no incision” in the outside-in (OI) technique for the creation of a femoral socket. Here we describe the suspensory femoral fixation using a retro-socket technique in single-bundle PCL reconstruction. By using this technique, it is possible to create a retrograde femoral socket for suspensory femoral fixation in an OI manner in a desirable direction and reduce angulation of the graft in the entry area of the femoral tunnel.

Evaluating the Femoral-Side Critical Corner in Posterior Cruciate Ligament Reconstruction: The Effect of Outside-In Versus Inside-Out Creation of Femoral Tunnels on Graft Contact Pressure in a Synthetic Knee Model

To characterize and compare the graft contact characteristics of outside-in (OI) and inside-out (IO) femoral tunnels during single-bundle reconstruction of the anterolateral bundle of the posterior cruciate ligament in a synthetic knee model. Femoral tunnels were separately made in 16 synthetic femora (8 OI and 8 IO). Achilles tendon allografts were fixed using suspensory fixation with a pressure sensor between the allograft and femoral tunnel. Grafts were cyclically loaded; force, contact area, contact pressure, and peak pressure at the aperture were measured. This process was repeated using the same allograft to assess the other tunnel angle in a separate specimen. IO specimens showed higher mean contact pressure at all loading cycles, with significance shown at 50N(P= .02). Peak pressure was also greater in IO specimens at all loading cycles and reached statistical significance at 100N(P= .04). IO specimens had a lower contact area at 150N(P= .04). No statistically significant differences in force were observed between the 2 groups. OI creation of the femoral tunnel for anterolateral bundle reconstruction of the posterior cruciate ligament resulted in decreased mean and peak contact pressures at the femoral aperture compared with IO tunnel creation at the specific trajectories and loading parameters tested in this synthetic femoral model. These biomechanical data suggest that OI creation of the femoral tunnel may help reduce invivo graft contact pressure at the femoral aperture. These data suggest that a tunnel drilled from OI may result in less graft pressure at the femoral aperture, which may prevent graft elongation and optimize graft survival.

Three-Dimensional Reconstruction Computed Tomography Evaluation of the Tunnel Location and Angle in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction: A Comparison of the Anteromedial Portal and Outside-in Techniques

PurposeThe purpose of this study was to compare the geometry and position of the femoral tunnel between the anteromedial portal (AMP) and outside-in (OI) techniques after anatomic single-bundle anterior cruciate ligament (ACL) reconstruction.Materials and MethodsWe evaluated 82 patients undergoing single-bundle ACL reconstruction with hamstring autografts using either the AMP (n=40) or OI (n=42) technique. The locations of the tunnel apertures were assessed by postoperative 3-dimensional computed tomography imaging. The femoral graft bending angle, femoral tunnel aperture shape, femoral tunnel length, and posterior wall breakage were also measured.ResultsThe mean femoral tunnel position parallel to the Blumensaat line was more caudally positioned in the AMP group than in the OI group (p=0.025) The mean femoral graft angle in the OI group (99.6°±7.1°) was significantly more acute than that of the AMP group (108.9°±10.2°, p<0.001). The mean height/width ratio of the AMP group (1.21±0.20) was significantly more ellipsoidal than that of the OI group (1.07±0.09, p<0.001).ConclusionsThe mean femoral tunnel position was significantly shallower in the AMP technique than in the OI technique. The OI technique might be more disadvantageous than the AMP technique in terms of the more acute bending angle.