Anatomic double-bundle anterior cruciate ligament reconstruction

Correlation between higher lateral tibial slope and inferior long term subjective outcomes following single bundle anterior cruciate ligament reconstruction

BACKGROUND

The impact of anatomical factors, such as the lateral tibial slope (LTS), on outcomes following anterior cruciate ligament (ACL) reconstruction is an area of growing interest. This study was led by the observation that patients with a higher LTS may have different recovery trajectories.

HYPOTHESIS/PURPOSE

The purpose of this study was to investigate the correlation between a higher LTS and long term subjective outcomes following single-bundle ACL reconstruction.

STUDY DESIGN

This study was designed as a retrospective cohort study.

METHODS

The study comprised 138 patients who underwent single-bundle ACL reconstruction. The LTS was measured on preoperative radiographs. Patient-reported outcome measures (PROMs) were collected, which included the Lysholm Knee Score, UCLA Activity Score, IKDC Score, and Tegner Activity Score, over a mean follow-up duration of 137 months.

RESULTS

A significant negative correlation was found between LTS and all measured PROMs (p < 0.001). The established cut-off value of LTS distinguishing between "Good" and "Fair" Lysholm scores was 8.35 degrees. Female patients have statistically significant higher LTS and lower PROMs scores than male. Patients with LTS greater than or equal to 8.35 had significantly lower PROMs, indicative of poorer functional and subjective outcomes.

CONCLUSION

Our findings suggest that a higher LTS is associated with inferior subjective outcomes following single-bundle ACL reconstruction in long term. The LTS cut-off value of 8.35 degrees could potentially be used as a reference in preoperative planning and patient counseling.

CLINICAL RELEVANCE

Understanding the relationship between LTS and ACL reconstruction outcomes could inform surgical planning and postoperative management. These findings highlight the need to consider anatomical variances, such as LTS, when assessing patient-specific risks and recovery expectations, contributing to the advancement of personalized care in sports medicine.

Platelet-rich plasma augmentation in anterior cruciate ligament reconstruction: Evidence is still too scattered. A scoping review of randomised controlled trials

PURPOSE

Platelet-rich plasma (PRP) augmentation has been proposed to improve the results of anterior cruciate ligament reconstruction (ACLR). The present study aims to quantify the available evidence to support the use of PRP as biological augmentation in ACLR surgery.

METHODS

A systematic literature search was conducted on the PubMed, Cochrane, Web of Science and Embase databases on 10 March 2023. Inclusion criteria were randomised controlled trials (RCTs), written in English, addressing PRP augmentation in ACLR surgery, with no time limitation. A scoping review was performed to map the body of literature by examining the evidence related to specific aspects of patients' treatment and evaluation. Risk of bias evaluation was performed with the Cochrane risk-of-bias tool for randomised trials Version 2 (RoB 2), while the quality assessment was performed with the use of the Coleman Score.

RESULTS

Out of 983 articles retrieved, 23 RCTs on 943 knees were included in this scoping review. PRP was administered in a liquid form in nine studies and clotted in 11 studies, while in three studies both liquid and clotted PRP were used. Hamstring auto/allografts were used in 14 studies, patellar tendon auto/allografts were used in eight studies and one study described ACLR with peroneus longus allografts. The map of the evidence documented high heterogeneity also in terms of surgical technique, objective and subjective outcome measures and radiological assessment, as well as follow-up times ranging from 1 day to 2 years, with virtually no overlapping data among studies neither in terms of treatments nor evaluations. Risk of bias evaluation showed an overall low quality of the included studies.

CONCLUSIONS

The available literature addressing PRP augmentation in ACLR is largely scattered. PRP was produced and applied following different procedures, and high variability was detected across the included studies for every aspect of ACLR surgery and evaluation. Currently, a meaningful comparison of the available studies is not possible as the quantification of the literature results is biased by their heterogeneity. Future studies should provide more standardisation to investigate the benefits of biological augmentation in ACL surgery and confirm the promising yet weak evidence of PRP potential as well as the most suitable application modality, before routine use in clinical practice.

LEVEL OF EVIDENCE

Levels I and II, scoping review.

The increased lateral tibial slope may result in inferior long-term clinical outcome after DB-ACL reconstruction

PURPOSE

To determine if there is a correlation between lateral tibial slope and long-term clinical results in patients who underwent double-bundle ACL reconstruction.

METHODS

We retrospectively reviewed patients that received double-bundle ACL reconstruction at a single institution by a single surgeon from January 2011 to December 2014. All the magnetic resonance imaging were reviewed and lateral tibial slopes (LTS) were recorded by an experienced surgeon and rechecked by the other two authors of this study that specialized in orthopedic knee surgery. The relationship between PROMs measurement and lateral tibial slope were analyzed. The patients were then separated into two groups (LTS > 7.4° and < 7.4°) according to the previous study.

RESULTS

A total of 119 patients were enrolled in this study. All enrolled patients were followed for at least 8 years. The PROMS result were negatively correlated with the lateral tibial slope (p values all < 0.001). The patients with high lateral tibial slope had significantly lower PROMS values (Lysholm 94.26 ± 5.61 vs 80.15 ± 8.28, p = 0.013; IKDC 82.99 ± 4.55 vs 70.09 ± 7.15, p = 0.003; Tegner 9.32 ± 0.95 vs 6.85 ± 1.99, p < 0.001). Finally, the LTS cutoff value between patients with "Good" and "Fair" Lysholm score in our study was 7.55 degrees.

CONCLUSIONS

Patients with high lateral tibial slope may result in inferior long-term subjective outcomes. The using of double-bundle ACL reconstruction along cannot overcome the negative impact caused by steep lateral tibial slope. A lateral tibial slope of 7.55° may be used as a cut-off for a good clinical outcome.

LEVEL OF EVIDENCE

III retrospective comparative prognostic trial.

Modified Anatomical Anterior Cruciate Ligament Reconstruction with Flat Semitendinosus Graft and C-shaped Tibial Canal

Every year, approximately 400,000 patients undergo anterior cruciate ligament (ACL) reconstruction surgery in the United States, accounting for almost 50% of all knee surgeries in the country. Recent studies have demonstrated that the ACL is a ribbon-like structure with a C-shaped tibial insertion and a flat femoral origin. This article introduces a modification of an ACL reconstruction technique. The modification renders the procedure easily reproducible with standard surgical instruments. We will describe a surgical technique modification that goes beyond the standard round bone tunnels and adopts a more anatomical approach using a C-shaped tibial canal and a flat femoral canal using a flat semitendinosus (semi-T) graft. The use of a semi-T graft better reproduces the ribbon-like ACL anatomy. The semi-T graft, a flat femoral canal, and a C-shaped tibial canal provide increased bone-tendon contact surface area and decreased diffusion length, resulting in improved tendon-bone healing. The modification proposed by our team makes the anatomical ribbon-like ACL graft, C-shaped tibial canal, and the flat femoral canal technique feasible in every orthopaedic operating room and mitigates costly specialized instrument.

Development and validation of a clinical prediction model for return to work after arthroscopic anterior crucial ligament reconstruction

BACKGROUND

Occupational reintegration after anterior cruciate ligament (ACL) rupture is an important clinical issue including economic and health-related perspectives. This study aims to develop and validate a clinical prediction model of return to work in patients with ACL reconstruction surgery considering evidence-based clinical, anthropometric and occupational factors.

METHODS

Data of 562 patients with an ACL rupture receiving an arthroscopic ACL reconstruction were used for analysis. A model for the binary outcome of experiencing an inability to work period of less or more than 14 days (model 1), and a model for finding predictor variables that are linearly associated with a continuous longer inability to work period of over 14 days (model 2) was calculated. Pre-operative determinants including patient characteristics and peri-operative factors were used as predictors for both models.

RESULTS

For model 1, the highest increase in odds was observed for the occupational type of work, followed by injury of the medial collateral ligament together with partial weight bearing. Small protective effects were observed for female sex, meniscal suture and work with light occupational strain. The type of occupational work, together with revision surgery, a longer duration of limited range of motion and the presence of cartilage therapy were risk factors for longer inability to work. Discrimination and calibration statistics were satisfactory in internal validation.

CONCLUSION

Within the framework of clinical consideration, these prediction models will serve as an estimator for patients, their treating physicians and the socioeconomic partners to forecast the individual cost and benefit of ACL injury.

Arthroscopic reconstruction of anterior cruciate ligaments with allograft: single-tunnel single-bundle versus single-tunnel double-bundle techniques

Purpose

To compare the clinical results of anterior cruciate ligament (ACL) reconstruction using the single-tunnel single-bundle (STSB) technique versus the single-tunnel double-bundle (STDB) technique.

Methods

This was a retrospective, single-center, single-surgeon study based on data collected from March 2012 to June 2013. According to our inclusion/exclusion criteria, a total of 78 patients (64 males, 14 females; mean age, 25.1 years) who underwent arthroscopic ACL reconstruction with anterior tibialis tendon allografts through either the STSB technique (36 cases) or the STDB technique (42 cases) in our department were recruited. The International Knee Documentation Committee (IKDC), Lysholm, and Tegner scores were used to evaluate the subjective function of the knee joint during the postoperative follow-up. The Lachman test and pivot shift test were used to objectively assess the stability of the knee.

Results

The average follow-up duration was 24.9 ± 1.8 months in the STSB group and 24.6 ± 1.7 months in the STDB group (P > 0.05). Patients in both groups recovered to the preoperative sports level with few complications. The postoperative Lysholm score (86.1 ± 7.5 vs. 47.7 ± 9.0 in the STSB group; 87.0 ± 7.1 vs. 48.2 ± 8.3 in the STDB group), IKDC score (87.8 ± 7.2 vs. 49.3 ± 6.1 in the STSB group; 88.7 ± 6.6 vs. 49.8 ± 6.3 in the STDB group), Tegner score (6.5 ± 1.3 vs. 2.5 ± 1.3 in the STSB group; 6.6 ± 1.2 vs. 2.6 ± 1.2 in the STDB group), Lachman test positive rate (8.3% vs. 89.9% in the STSB group; 7.1% vs. 85.7% in the STDB group), and pivot shift test positive rate (27.8% vs. 63.9% in the STSB group; 7.1% vs. 69.0% in the STDB group) were significantly improved compared to the preoperative status in both groups (P < 0.05). However, no statistically significant difference was observed between the two groups at the final follow-up (P > 0.05), except for the pivot shift test positive rate in the STDB group versus the STSB group (7.1% vs. 27.8%, P < 0.05).

Conclusions

The STDB technique achieved a satisfactory clinical outcome with better rotational stability compared to the traditional STSB technique and therefore provided an effective option for ACL reconstruction.

Level of evidence

Case series, Level IV.

Posterior Tibial Slope Increases Anterior Cruciate Ligament Stress in Bi-Cruciate Retaining Total Knee Arthroplasty: In Vivo Kinematic Analysis

The study design involved here is experimental in nature. The resection of the anterior cruciate ligament (ACL) during conventional total knee arthroplasty (TKA) has been considered a potential factor leading to abnormal in vivo knee kinematics. Bi-cruciate retaining (BCR) TKA designs allow the preservation of the ACL with the potential to restore native knee kinematics. This study aimed to investigate the effect of posterior tibial slope (PTS) on stress experienced by the ACL during weight bearing sit-to-stand (STS) and single-leg deep lunge. The ACL elongation patterns were measured in 30 unilateral BCR TKA patients during weight-bearing STS and single-leg deep lunge using a validated dual fluoroscopic tracking technique. The minimum normalized stress within the anteromedial (AM) and posterolateral (PL) bundle of the ACL during weight-bearing STS and single-leg deep lunge was found at a PTS of 3.7 degrees. The maximum AM and PL bundle stresses were observed at a PTS of 8.5 and 9.3 degrees, respectively during STS and at 8.4, and 9.1 degrees, respectively during single-leg deep lunge. There was a significant positive correlation between PTS and stress observed within the AM and PL bundle of the ACL during weight-bearing STS (R ² = 0.37; p < 0.01; R2  = 0.36; p = 0.01) and single-leg deep lunge (R ² = 0.42; p < 0.01; R ²= 0.40; p < 0.01). The study demonstrates that PTS of operated BCR TKA knees has a significant impact on the stress experienced by the preserved ACL during weight-bearing STS and single-leg deep lunge. This suggests that avoiding excessive PTS may be one of the surgical implant alignment factors to consider during surgery to minimize increased loading of the preserved ACL.

A Simplified Double-Bundle Anterior Cruciate Ligament Reconstruction by the Three-Inside Technique With Two Suspension Buttons and One Interference Screw

In comparison with the single-bundle technique, double-bundle anterior cruciate ligament (ACL) reconstruction has proven its superiority regarding biomechanical studies and clinical outcomes in both rotational knee stability and anterior translation function. However, the complexity and risk of complications remain a great concern for the orthopaedic surgeon performing double-bundle ACL reconstruction. We present a simplified double-bundle ACL reconstruction by the 3-inside technique with 2 suspension buttons and 1 interference screw. The semitendinosus tendon is tripled to be the anteromedial (AM) bundle, whereas the gracilis is doubled for the posterolateral (PL) bundle. We perform a 3-socket approach with an inside-out femoral tunnel for the AM bundle, an outside-in femoral tunnel for the PL bundle, and a retrograde tibial socket for the tibial bundle. Thus, this technique is, simply, a combination of 2 procedures: one single all-inside method (for the AM bundle) and one outside-in method (for the PL bundle), with which most arthroscopic surgeons are familiar. The AM and PL bundles are fixed at 30° and 45°, respectively, using 2 suspension buttons and 1 interference screw. Our simplified technique could reduce surgical costs and minimize complications while maintaining isometric position and appropriate graft size for each patient.

Anatomical Anterior Cruciate Ligament Reconstruction with Hamstring Tendon Autografts: A Comparative Study of Three Different Techniques

The ideal procedure for anterior cruciate ligament (ACL) reconstruction is one that can achieve anatomical restoration for a better ACL function. This retrospective comparative study was conducted to evaluate the objective and subjective clinical results of the conventional single-bundle femoral round (SBR) tunnel technique, the single-bundle femoral oval (SBO) tunnel technique, and the double-bundle (DB) surgical technique for anatomical ACL reconstruction with hamstring tendon autografts. Patients who underwent the SBO, SBR, and DB ACL reconstructions from January 2016 to August 2017 were included in this study. A total of 163 patients underwent different surgical techniques; 41 patients underwent the SBO procedure, 78 patients received SBR, and the remaining 44 patients underwent the DB procedure. The Lachman's test, pivot-shift test, Lysholm's score, International Knee Documentation Committee (IKDC) score, and Tegner's score were compared among groups postoperatively. KT-1000 was used to measure the anterior laxity of the knee. Magnetic resonance imaging was used to compare the ACL graft maturity. Second-look arthroscopy was conducted to compare the graft status and synovial coverage. Significant differences among groups were found with respect to the Lysholm's score, Tegner's score, and IKDC score. Patients in the SBO and DB groups acquired higher functional scores than the SBR group. More patients with positive pivot-shift test were observed in the SBR group than other groups at 12- and 24-month postoperative follow-ups. The postoperative KT-1000 was better in the SBO and DB groups than in the SBR group. The mean signal/noise quotient (SNQ) of the SBO group was 2.70 ± 0.92, significantly lower than 3.58 ± 1.21 of the SBR group. Despite a higher proportion of patients with grade B or C synovial coverage and partial graft injury found in the SBR group, there were no significant differences among the groups. The SBO and DB technique achieved better clinical results than the SBR technique. The SBO technique was indeed an ideal surgical procedure for ACL reconstruction provided that the shortcoming of DB technique must be taken into account. This is a Level III, retrospective comparative study.

No Difference in Ligamentous Strain or Knee Kinematics Between Rectangular or Cylindrical Femoral Tunnels During Anatomic ACL Reconstruction With a Bone-Patellar Tendon-Bone Graft

BACKGROUND

As our understanding of anterior cruciate ligament (ACL) anatomy has evolved, surgical techniques to better replicate the native anatomy have been developed. It has been proposed that the introduction of a rectangular socket ACL reconstruction to replace a ribbon-shaped ACL has the potential to improve knee kinematics after ACL reconstruction.

PURPOSE

To compare a rectangular femoral tunnel (RFT) with a cylindrical femoral tunnel (CFT) in terms of replicating native ACL strain and knee kinematics in a time-zero biomechanical anatomic ACL reconstruction model using a bone-patellar tendon-bone (BTB) graft.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 16 fresh-frozen, human cadaveric knees were tested in a 5 degrees of freedom, computed tomography-compatible joint motion simulator. Knees were tested with the ACL intact before randomization to RFT or CFT ACL reconstruction using a BTB graft. An anterior translation load and an internal rotation moment were each applied at 0°, 30°, 60°, and 90° of knee flexion. A simulated pivot shift was performed at 0° and 30° of knee flexion. Ligament strain and knee kinematics were assessed using computed tomography facilitated by insertion of zirconium dioxide beads placed within the substance of the native ACL and BTB grafts.

RESULTS

For the ACL-intact state, there were no differences between groups in terms of ACL strain or knee kinematics. After ACL reconstruction, there were no differences in ACL graft strain when comparing the RFT and CFT groups. At 60° of knee flexion with anterior translation load, there was significantly reduced strain in the reconstructed state ([mean ±standard deviation] CFT native, 2.82 ± 3.54 vs CFT reconstructed, 0.95 ± 2.69; RFT native, 2.77 ± 1.71 vs RFT reconstructed, 1.40 ± 1.76) independent of the femoral tunnel type. In terms of knee kinematics, there were no differences when comparing the RFT and CFT groups. Both reconstructive techniques were mostly effective in restoring native knee kinematics and ligament strain patterns as compared with the native ACL.

CONCLUSION

In the time-zero biomechanical environment, similar graft strains and knee kinematics were achieved using RFT and CFT BTB ACL reconstructions. Both techniques appeared to be equally effective in restoring kinematics associated with the native ACL state.

CLINICAL RELEVANCE

These data suggest that in terms of knee kinematics and graft strain, there is no benefit in performing the more technically challenging RFT as compared with a CFT BTB ACL reconstruction.

Interbundle Impingement Pressure in Individualized and Nonindividualized Double-Bundle Anterior Cruciate Ligament Reconstruction: A Cadaveric Study

Background:

Graft impingement is one of the main concerns in double-bundle anterior cruciate ligament reconstruction (DB-ACLR). Impingement between the anteromedial (AM) and posterolateral (PL) bundles has been postulated to cause graft deterioration or rerupture, but this has not been thoroughly investigated, and the interbundle impingement pressure (IIP) has not been well researched.

Purpose:

To determine the IIP between the AM and PL bundles in the native anterior cruciate ligament (ACL) and in DB-ACLR with individualized and nonindividualized double-tunnel placement.

Study Design:

Controlled laboratory study.

Methods:

A total of 30 fresh-frozen, nonpaired, human cadaveric knees were randomly divided into 3 groups of 10 knees: native intact ACL (NI group), DB-ACLR tunnel placement using the preserved remnant procedure (individualized reconstruction) (PR group), and DB-ACLR tunnel placement using the bony landmark procedure (nonindividualized reconstruction) (BL group). Pressure sensors were inserted between the AM and PL bundles. The knee was moved passively from full extension to full flexion, and the IIP between the 2 ACL bundles was measured every 15°. Similarly, the impingement pressure was measured between the ACL and intercondylar roof and between the ACL and posterior cruciate ligament (PCL).

Results:

No significant differences were found in the maximum, mean, or minimum ACL-roof and ACL-PCL impingement pressures among the 3 groups. The IIP significantly increased when the knee joint was flexed >120° in all 3 groups (P < .001). Compared with the other 2 groups, the BL group had significantly higher maximum and mean IIP throughout the range of knee movement (P < .001) and from maximum extension to 120° of flexion (P < .001). The BL group also had significantly higher minimum IIP than the other 2 groups when knee flexion was >120° (P < .001). No significant differences were seen in maximum, minimum, or mean IIP between the NI and PR groups.

Conclusion:

The PR procedure (individualized DB-ACLR) was more consistent with the interbundle biomechanical conditions of the native ACL, whereas the BL procedure (nonindividualized DB-ACLR) had higher maximum and mean IIP. The IIP was higher than the ACL–intercondylar roof or ACL-PCL pressures, and it increased significantly when knee flexion was >120°.

Clinical Relevance:

These data suggest that surgeons can perform individualized DB-ACLR using preserved remnants for tunnel placement as impingement-free DB-ACLR.

Remnant-Tensioning Single-Bundle Anterior Cruciate Ligament Reconstruction Provides Comparable Stability to and Better Graft Vascularity Than Double-Bundle Anterior Cruciate Ligament Reconstruction in Acute or Subacute Injury: A Prospective Randomized Controlled Study Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

PURPOSE

To compare the clinical, second-look arthroscopic, magnetic resonance imaging (MRI), and dynamic-contrast-enhanced MRI (DCE-MRI) findings between remnant-tensioning single-bundle (RT-SB) and double-bundle (DB) anterior cruciate ligament reconstruction (ACLR).

METHODS

Sixty-seven patients with acute or subacute anterior cruciate ligament (ACL) injury were randomized to undergo RT-SB or DB ACLR. Twenty-six patients in the RT-SB group and 28 in the DB group were evaluated using stability tests (Lachman test, pivot-shift test, and KT-2000 arthrometer) and multiple clinical scores. One year postoperatively, all 54 patients underwent MRI for evaluation of graft continuity and graft signal/noise quotient and DCE-MRI for the calculation of normalized area under the curve (nAUC) as a marker of graft vascularity. Among them, 41 patients underwent second-look arthroscopy for the evaluation of graft continuity, graft tension, and synovialization. The results were compared between the 2 groups.

RESULTS

At the minimum 2-year follow-up (28.7 ± 6.4 months), the stability tests, clinical scores, second-look arthroscopic findings, and MRI findings were not significantly different between the groups. However, the mean nAUC values on DCE-MRI for the ACL graft were significantly higher in the RT-SB group than those in the DB group in all 3 zones (nAUC_proximal, P = .005; nAUC_middle, P = .021; nAUC_distal, P = .027; and nAUC_average, P = .008).

CONCLUSION

For acute or subacute ACL injury, the RT-SB ACLR showed an outcome comparable to that of DB ACLR in terms of knee stability, clinical scores, MRI findings, and second-look arthroscopic findings. Moreover, RT-SB ACLR showed better graft vascularity 1 year postoperatively than DB ACLR using DCE-MRI.

LEVEL OF EVIDENCE

II, prospective randomized controlled trial.

Aperture elongation of the femoral tunnel on the lateral cortex in anatomical double-bundle anterior cruciate ligament reconstruction using the outside-in technique

In anatomical anterior cruciate ligament reconstruction surgery using the outside-in technique, the aperture of the femoral lateral cortex may become elliptical.Retrospective cross-sectional studyTo evaluate the extent of elliptical eccentricity in lateral apertures relative to aperture positioning and clinical failure rate in anatomical anterior cruciate ligament double-bundle reconstruction using outside-in technique.In 75 patients, the aperture elongation factor was defined as the ratio of the major axis of the elliptical aperture to the drill size. Using the lateral epicondyle as a reference point, the lateral femur was divided into sections by distance and angle, and the minimum area was evaluated to assess the relationship between the elongation factor and aperture position of the lateral cortex for each bundle. The incidence and associated clinical performance regarding cortical button migration were also investigated.Aperture elongation factors were 120.2 ± 13.3% and 120.0 ± 16.3% on the anteromedial (AM) and posterolateral (PL) sides, respectively. Femoral tunnel elongation was smallest when the entry point axis were both between 30 to 60° and distance was between 10 to 20 mm and 0 to 10 mm on the AM and PL sides, respectively. During the postoperative follow-up period, intra-tunnel migration was confirmed in 4 of 75 cases (5.3%). Fixation failure neither affected clinical scores nor knee laxity.Areas of minimum elongation for each bundle on both AM and PL sides were found anteroproximally to the lateral epicondyle and positioned near each other. Elongation did not directly affect the clinical outcome.Level of evidence grade: prognostic level III.

A Review on Finite Element Modeling and Simulation of the Anterior Cruciate Ligament Reconstruction

The anterior cruciate ligament (ACL) constitutes one of the most important stabilizing tissues of the knee joint whose rapture is very prevalent. ACL reconstruction (ACLR) from a graft is a surgery which yields the best outcome. Taking into account the complicated nature of this operation and the high cost of experiments, finite element (FE) simulations can become a valuable tool for evaluating the surgery in a pre-clinical setting. The present study summarizes, for the first time, the current advancement in ACLR in both clinical and computational level. It also emphasizes on the material modeling and properties of the most popular grafts as well as modeling of different surgery techniques. It can be concluded that more effort is needed to be put toward more realistic simulation of the surgery, including also the use of two bundles for graft representation, graft pretension and artificial grafts. Furthermore, muscles and synovial fluid need to be included, while patellofemoral joint is an important bone that is rarely used. More realistic models are also required for soft tissues, as most articles used isotropic linear elastic models and springs. In summary, accurate and realistic FE analysis in conjunction with multidisciplinary collaboration could contribute to ACLR improvement provided that several important aspects are carefully considered.

Knee Ligament Anatomy and Biomechanics

An understanding of knee ligament anatomy and biomechanics is foundational for physicians treating knee injuries, especially the more rare and morbid multiligamentous knee injuries. This chapter examines the roles that the cruciate and collateral anatomy and morphology play in their kinematics. Additionally, the biomechanics of the ACL, PCL, MCL, and LCL are discussed as they have surgical and reconstructive implications.

Comparative clinical outcomes of anterolateral ligament reconstruction versus lateral extra-articular tenodesis in combination with anterior cruciate ligament reconstruction: systematic review and meta-analysis

BACKGROUND

Anterolateral augmentation procedures can be divided into traditional lateral extra-articular tenodesis (LET) and modern anterolateral ligament (ALL) reconstruction. Nevertheless, no studies have compared the clinical results between LET and ALL reconstruction, when combined with intra-articular ACL reconstruction. This study was therefore designed to compare the clinical results, including the anterior translation, rotational laxity, and patient-reported outcomes, in a group of patients who underwent ACL reconstruction combined with LET or ALL reconstruction.

METHODS

All studies systematically searched until March 2018 without any language restriction that reported the results of a lateral extra-articular stabilization procedure using either LET or ALL reconstruction methods combined with ACL reconstruction were evaluated. Two reviewers independently recorded data from each study, including the sample size, improvement in Lysholm score, and the number of patients with each grade of knee laxity using Lachman and pivot shift tests.

RESULTS

The pooled results of ten studies showed that the postoperative proportion of knees with grade 2 or 3 on the Lachman test was significantly higher following LET compared with ALL reconstruction in combination with ACL reconstruction (10.8%, 95% confidence interval [CI]: 6.6-17.1% vs. 1.5%, 95% CI 0.5-4.5%; p = 0.001). However, the pooled results of 12 studies showed that the proportion of knees that belonged to grade 2 or 3 on the pivot shift test, indicating poor rotational stability, was similar between these two techniques (4.9%, 95% CI 2.0-11.5% vs. 2.3%, 95% CI 1.1-4.5%; p = 0.101). The pooled improvements in Lysholm scores in these two groups were also similar (32.3, 95% CI 26.8-37.9 vs. 25.7, 95% CI 16.7-34.7, p = 0.218).

CONCLUSION

LET could lead to worse anterior instability than with ALL reconstruction when these two approaches were combined with single-bundle ACL reconstruction. However, rotational stability and patient-reported outcomes were similar between the techniques.

The interposition of soft tissue between the cortical button and femoral lateral cortex significantly increases button migration but does not negatively affect knee stability and clinical outcome

BACKGROUND

In clinical practice, soft tissue interposition may occur during femoral graft fixation. Soft tissue interposition between the lateral femoral cortex and the cortical button may affect graft tension and related longitudinal graft motion in the tunnel. We aimed to investigate the effect of soft tissue interposition on button migration and clinical outcomes in anatomical single-bundle anterior cruciate ligament reconstruction.

METHODS

Eighty-four patients aged 18-40 years, who underwent anatomical single-bundle anterior cruciate ligament reconstruction with quadruple hamstring autograft were included. Patients were divided into two groups as Group 1 (n = 32) with soft tissue interposition between the cortical button and cortex, and Group 2 (n = 52) without soft tissue interposition. At the one-year follow-up visit, the anteroposterior knee stability of the patients was evaluated using the Lachman test and KT-2000 arthrometer, and rotational stability was assessed with the pivot shift test. The Lysholm knee score was used to evaluate the functional outcome of the patients. Relationship between tissue interposition and clinical outcome, and button migration was examined.

RESULTS

Button migration was observed in 12 patients in Group 1 (37.5%) and two patients (3.84%) in Group 2 (p < 0.001). However, no significant difference was observed between patients with and without tissue interposition or those with and without button migration regarding knee stability parameters and clinical outcome (p < 0.05).

CONCLUSIONS

Postoperative tissue interposition is found to be associated with cortical button migration during the follow-up. However, it does not affect the clinical outcome.

Eight-year results of transtibial nonanatomic single-bundle versus double-bundle anterior cruciate ligament reconstruction: Clinical, radiologic outcomes and survivorship

PURPOSE

To compare the long term outcomes of transtibial nonanatomic single-bundle (SB) and double-bundle (DB) anterior cruciate ligament (ACL) reconstruction.

METHODS

Between January 2008 and September 2010, we retrospectively evaluated 377 patients who underwent primary ACL reconstruction and who were available at 8 years of follow-up. Patients who received transtibial nonanatomic SB ACL reconstruction ( n = 263) were assigned to group SB and DB ACL reconstruction ( n = 114) to group DB. The patients were assessed with the International Knee Documentation Committee (IKDC), the Lysholm scores, Tegner activity score, knee joint stability tests, and patellofemoral osteoarthritis (OA) findings using the Kellgren-Lawrence (K-L) classification. Contralateral ACL (CACL) injury was also evaluated.

RESULTS

Thirteen patients underwent revision ACL surgery during the follow-up. Ultimately, 256 patients in group SB and 108 patients in group DB were available at the 8-year follow-up. At final follow-up, the IKDC subjective score ( p = 0.04) and Lysholm score ( p = 0.02) showed significantly superior results in group DB compared to group SB. However, there was no significant difference of Tegner activity score ( p = 0.30), range of motion ( p = 0.81), and knee joint stability tests. There was significant progression of patellofemoral OA between preoperative and final follow-up in ipsilateral knee of both groups but not significant progression in contralateral knee. However, there was no significant difference between the two groups at the follow-up. There were 2.7% ipsilateral ACL graft failure in group SB, compared with 5.2% in group DB ( p = 0.12) and 6.4% CACL tear in group SB, compared with 5.2% in group DB ( p = 0.65). The mean survivorship of ACL graft was 9.47 ± 0.05 years (95% confidence interval (CI), 9.36-9.58) in group SB and 9.87 ± 0.16 years (95% CI, 9.54-10.20) in group DB, and there was no significant difference ( p = 0.25).

CONCLUSION

DB ACL reconstruction resulted in significantly better clinical IKDC subjective scores and Lysholm scores. However, most of the differences in clinical scores were small, and the clinical relevance of this difference is unknown. In addition, there was no significant difference in Tegner activity score, knee joint stability tests, patellofemoral OA, and survivor rate of the ACL graft and CACL after reconstruction after a minimum of 8-year follow-up. Level of Evidence: Cohort study; level of evidence, 3.

[Comparison of femoral oval tunnel technique and round tunnel technique in single-bundle anterior cruciate ligament reconstruction]

OBJECTIVE

To evaluate the effectiveness of femoral oval tunnel technique versus round tunnel technique in single-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

Between March 2016 and February 2018, 125 patients who underwent anatomical single-bundle ACL reconstruction with hamstring tendon and met the inclusive criteria were included in the retrospective study. Of the included patients, 43 patients underwent ACL reconstruction using oval tunnel technique (group A) and 82 patients with round tunnel technique (group B). There was no significant difference between the two groups in terms of age, gender, body mass index, the interval between injury and operation, the injured side, the cause of injury, and preoperative Lysholm score, International Knee Documentation Committee (IKDC) score, Tegner score, and the outcome of KT-1000 measurement ( P>0.05). At 3, 6, 12, and 24 months after operation, the knee function scores (Lysholm score, IKDC score, Tegner score) were recorded; and KT-1000 was used to evaluate the knee stability. The position and shape of the tunnels were evaluated by the three-dimensional CT (3D-CT) at 1 day after operation; and MRI was performed at 6, 12, and 24 months to calculate the signal/noise quotient (SNQ) of ACL grafts. Secondary arthroscopy was conducted to estimate the graft status, synovial coverage, and tension.

RESULTS

All patients were followed up 12-26 months (mean, 23 months). Two patients in group A and 5 patients in group B presented with redness and swelling of the surgical site, 1 patient in group B sustained a tibial tunnel fracture, and 1 patient in group A had postoperative stiffness. The Lysholm score, IKDC score, and Tegner score were significantly higher in group A than in group B at the different time points ( P<0.05) except for the Tegner score at 3 months. The outcomes of KT-1000 measurement were significantly lower in group A than in group B ( P<0.05). The entrances of the femoral tunnel and tibial tunnel in both groups were within the ACL anatomical footprint confirmed by 3D-CT. No re-rupture of ACL occurred confirmed by the MRI. There was no significant difference in SNQs of the middle and distal grafts between the two groups at 6 months ( P>0.05), whereas the SNQ of the proximal grafts in group A was significantly lower than that in group B ( P<0.05). The SNQs of the proximal, middle, and distal grafts in group A were significantly lower than those in group B at 12 and 24 months after operation ( P<0.05). Twenty-one patients in group A and 38 patients in group B underwent secondary arthroscopy and the results showed no significant difference in graft status, synovial coverage, and tension between the two groups ( P>0.05).

CONCLUSION

The effectiveness and graft maturity of the femoral oval tunnel technique were superior to the round tunnel technique. The single-bundle ACL reconstruction with femoral oval tunnel technique can obtain a better knee function.

Mechanical evaluation of tibial fixation of the hamstring tendon in anterior cruciate ligament double-bundle reconstruction with and without interference screws

OBJECTIVE

The objective of this study was to compare two postero-lateral bundle (PLB) tibial fixation techniques for the reconstruction of the anterior cruciate ligament with double bundle: a technique without the use of an interference screw, preserving the native tibial insertion of the tendons of the gracilis and semitendineous muscles, and a technique with the use of an interference screw and without preserving the insertion of the tendons.

METHODS

A comparative study was conducted in cadavers with a universal mechanical test machine. In total, 23 cadaver knees were randomized for tibial fixation of the PLB using the two techniques: Maintaining the tibial insertion of the tendons during reconstruction, without the use of an interference screw (group A, 11 cases); and fixating the graft with an interference screw, without maintaining the insertion of the tendons (group B, 12 cases). A continuous traction was performed (20 mm/min) in the same direction as the produced tunnel, and force (N), elongation (mm), rigidity (N/mm), and tension (N/mm2) were objectively determined in each group.

RESULTS

Group A exhibited a maximum force (MF) of 315.4±124.7 N; maximum tension of 13.57±3.65 N/mm2; maximum elongation of 19.73±4.76 mm; force at the limit of proportionality (FLP) of 240.6±144.0 N; and an elongation at the limit of proportionality of 14.37±6.58 mm. Group B exhibited a MF of 195.7±71.8 N; maximum tension of 8.8±3.81 N/mm2; maximum elongation of 15.3±10.73 mm; FLP of 150.1±68.7 N; and an elongation at the limit of proportionality of 6.86±2.42 mm. When comparing the two groups, significant differences were observed in the variables of maximum force (p=0.016), maximum tension (p=0.019), maximum elongation (p=0.007), and elongation at the limit of proportionality (p=0.003).

CONCLUSION

The use of the native insertion of the semitendineous and gracilis tendons, without an additional fixation device, presented mechanical superiority over their fixation with interference screws.

Does non-contact or delayed contact of an adjustable-loop femoral button affect knee stability following anterior cruciate ligament reconstruction?

BACKGROUND

The purpose of this study was to investigate whether cortical non-contact or delayed contact of an adjustable-loop button for femoral fixation could affect knee stability following anterior cruciate ligament (ACL) reconstruction.

METHODS

Eighty subjects who underwent single-bundle ACL reconstruction using an adjustable-loop femoral cortical button were retrospectively reviewed regarding patient demographics, graft size, combined surgery, and postoperative 2-year results of knee stability, functional scores, and radiographic tunnel widening. We compared the contact and the non-contact groups determined by position of the button observed in immediate postoperative radiographs. According to 2-year postoperative radiographs, the non-contact group was further divided into two subgroups (delayed contact and persisting non-contact subgroups) and results were compared.

RESULTS

The contact group had 46 patients and the non-contact group had 34 patients. The average gap distance in the non-contact group was 1.9 ± 0.6 (1.1-3.4) mm. There were no significant differences in KT-1000 arthrometric knee stability (p = .667) or Lysholm score (p = .198), or International Knee Documentation Committee (IKDC) score (p = .091) between the two groups. No significant differences in tunnel widening were found at femoral and tibial tunnels on anteroposterior and lateral radiographs (p > .1, all tunnels). In addition, delayed contact subgroup and persisting non-contact subgroup showed similar radiographic and clinical outcomes.

CONCLUSION

Surgeons should strive to obtain cortical contact of the adjustable-loop femoral button. Nevertheless, cortical non-contact with less than 3 mm of gap distance did not affect knee stability, radiographic outcomes, or clinical outcomes.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Single-tunnel anatomic double-bundle anterior cruciate ligament reconstruction has the same effectiveness as double femoral, double tibial tunnel: A prospective randomized study

PURPOSE

To investigate whether single femoral, single tibial tunnel anatomic double-bundle anterior cruciate ligament (ACL) reconstruction is equal to or superior to double femoral, double tibial tunnel ACL double-bundle anatomic reconstruction in terms of restoring the stability and functions of the knee joint.

METHODS

A prospective clinical study was performed to compare 30 cases of single-tunnel ACL double-bundle anatomic reconstruction to 28 cases of double-tunnel ACL double-bundle anatomic reconstruction, with average follow-up of 36 months. All graft tendons were hamstring tendon autografts. Tunnel placements in all the cases were made anatomically. Clinical results were collected after reconstruction. Graft appearance, meniscus status and cartilage state under arthroscopy were compared and analyzed.

RESULTS

Tunnel placements were in the anatomic positions in both groups. On the lateral pivot-shift test performed at 36 months postoperatively, there was no significant difference between groups. Clinical results such as International Knee Documentation Committee score, Tegner activity scale, and range of motion showed no significant differences between the groups. The mean thickness of anteromedial graft was reduced by 10.3% and that of the posterolateral graft was reduced by 11.1% from the original graft thickness evaluated by magnetic resonance imaging. No new meniscal tears were found either group; however, cartilage damage occurred in the double-tunnel group at 39.3%, and this rate was significantly higher than that in the single-tunnel group (10.0%).

CONCLUSION

Single femoral, single tibial tunnel anatomic double-bundle ACL reconstruction has the same effectiveness as the double femoral, double tibial tunnel in restoring the knee's stability and functions.

Anterolateral Complex Reconstruction: Another Fad or Method to Improve ACL Outcomes?

Anterolateral rotational laxity of the knee is a persistent problem following anterior cruciate ligament reconstruction (ACLR) that can lead to increased rates of graft failure. Renewed interest in the anterolateral complex of the knee has led to a resurgence in the use of adjunctive techniques such as lateral extra-articular tenodesis and anterolateral ligament reconstruction. Use of these techniques can restore normal knee kinematics and potentially thereby reduce the rate of graft failure. Historically, experience with modified ACLR techniques such as the double-bundle ACLR have shown that improved biomechanics is not always reflected in clinical outcome trials. Additional procedures also come with additional costs and further economic analysis needs to be performed to clarify whether these additional costs are offset by improved clinical and societal outcomes in the longer-term.

In-vivo elongation of anterior and posterior cruciate ligament in bi-cruciate retaining total knee arthroplasty

Anterior and posterior cruciate ligament (ACL and PCL) sacrifice in contemporary total knee arthroplasty (TKA) has been considered a potential factor leading to abnormal knee kinematics. Bi-cruciate retaining (BCR) TKA design allows retention of both ACL and PCL. However, there is a limited data on the ACL/PCL in-vivo elongation characteristics of BCR TKA. The study aimed to evaluate and compare the in-vivo elongation patterns of ACL/PCL between BCR TKA and contralateral non-implanted knee and to explore potential factors leading to the changed elongation patterns between limbs. ACL/PCL elongations of both knees during sit-to-stand were measured in 29 unilateral BCR TKA patients using a validated dual fluoroscopic tracking technique. Joint gap changes of the BCR TKA knees relative to the contralateral knee were quantified. BCR TKA and the contralateral non-implanted knee exhibited similar ACL elongation at extension and clinical anterior knee laxity. However, BCR TKA showed significantly greater PCL elongation during flexion than the non-implanted knee. Variation of changed elongation was observed for both ACL and PCL, suggesting a heterogeneous restoration of normal ACL/PCL functions. A significant correlation was found between extension joint gap change and the change of ACL elongation, highlighting the importance of precise joint line restoration and soft tissue balancing during BCR TKA surgery. Our findings suggest that BCR TKA did not fully restore "near-normal" cruciate ligament elongation patterns and anteroposterior stability. Considerable heterogeneity remains in the retained ligament elongation patterns and warrants further investigations of multifactorial factors to optimize ACL/PCL functions in BCR TKA. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3239-3246, 2018.

Double-bundle anterior cruciate ligament reconstruction is better than single-bundle reconstruction in terms of objective assessment but not in terms of subjective score

PURPOSE

A comparison of clinical outcomes between double-bundle (DB) and single-bundle (SB) anterior cruciate ligament (ACL) reconstruction for patients with ACL injury.

METHODS

Sixty patients were treated with either SB (n = 30) or DB (n = 30) ACL reconstruction between 2011 and 2012. The hamstring tendons were autografted with suspensory fixation on the femoral side, while a bio-absorbable interference screw was used for fixation on the tibial side. These patients were evaluated using Lysholm score, International Knee Documentation Committee (IKDC) forms (both objective and subjective), Lachman test, pivot shift test, and KT 1000 arthrometer.

RESULTS

After a median follow-up duration of 35.5 months (ranging between 30 and 42 months), the frequency of patients who had high objective IKDC scores was significantly higher in the DB group than those in the SB group. In terms of DB, the Lachman test was normal in 26 patients (86.7%), nearly normal in three patients (10%), and abnormal in one patient (3.3%); comparatively, in terms of SB, the Lachman test was normal in 20 patients (66.7%), nearly normal in eight patients (26.7%) and abnormal in two patients (6.6%). The pivot shift test was negative in 29 patients (96.7%) and 21 patients (70%) for DB and SB, respectively. The average KT-1000 side-to-side difference was 1.0 mm for DB and 1.5 mm for SB. The subjective IKDC and Lysholm score showed non-significant differences between both techniques.

CONCLUSION

Double-bundle ACL reconstruction was found to have a significant advantage in anterior and rotational stability as well as objective IKDC than that of SB reconstruction. However, subjective measurements showed no statistical differences between the techniques.

LEVEL OF EVIDENCE

II.

Combined Double Bundle Anterior Cruciate Ligament Reconstruction and Anterolateral Ligament Reconstruction

A double-bundle anterior cruciate ligament (ACL) reconstruction associated with an anterolateral ligament (ALL) reconstructions is performed. The semitendinosus and gracilis are harvested. At knee maximum flexion, the anteromedial (AM) femoral tunnel is performed in the AM footprint area. Through the anterolateral portal, the tip of the outside-in femoral guide is placed in the posterolateral footprint area. The guide sleeve is pushed onto the lateral femoral cortex at the ALL attachment. At 110° knee flexion, the posterolateral-ALL tunnel is performed. The tibial ACL tunnel is performed as usual. The tibial guide is placed between the ALL tibial attachment and the tibial ACL tunnel entrance to perform the ALL tibial tunnel. The gracilis graft is introduced from caudal to cranial, achieving fixation with a 6-mm diameter screw (outside-in). The AM femoral fixation is achieved with a suspension device. ACL tibial graft fixation is achieved with a screw. Afterward, the gracilis is passed under the fascia lata to the tibial entry point. A 6-mm diameter screw is placed from the external cortex into the tibial ALL tunnel. The biomechanical advantage of the double-bundle ACL reconstruction with the biomechanical advantage of the ALL anatomic reconstruction is achieved.

Effect of Intraoperative Platelet-Rich Plasma Treatment on Postoperative Donor Site Knee Pain in Patellar Tendon Autograft Anterior Cruciate Ligament Reconstruction: A Double-Blind Randomized Controlled Trial

BACKGROUND

Donor site morbidity in the form of anterior knee pain is a frequent complication after bone-patellar tendon-bone (BPTB) autograft anterior cruciate ligament (ACL) reconstruction. Hypothesis/Purpose: The purpose was to examine the effect of the intraoperative administration of platelet-rich plasma (PRP) on postoperative kneeling pain. It was hypothesized that PRP treatment would reduce knee pain.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Fifty patients (mean ± SD age, 30 ± 12 years) undergoing BPTB ACL autograft reconstruction were randomized to the PRP (n = 27) or sham (n = 23) treatment. In either case, 10 mL of venous blood was drawn before the induction of anesthesia and either discarded (sham) or processed (PRP) for preparation of a PRP gel to be later mixed with donor site bone chips and inserted into the patellar defect. At 12 weeks, 6 months, 1 year, and 2 years after surgery, patients completed International Knee Documentation Committee (IKDC) forms and visual analog scale pain scores for activities of daily living and kneeling. Healing indices at the donor site were assessed by routine noncontrast magnetic resonance imaging (MRI) at 6 months. Mixed-model analysis of variance was used to assess the effect of PRP on patient symptoms and MRI indices of donor site healing, as measured by the width of the donor site defect.

RESULTS

Kneeling pain, pain with activities of daily living, and IKDC scores were not different between treatment groups at any of the time intervals ( P = .08-.83). Kneeling pain improved from 12 weeks to 6 months and from 1 to 2 years ( P < .05). IKDC scores improved substantially from 12 weeks to 6 months ( P < .001) and continued to improve to 2 years (PRP, 86 ± 19; sham, 89 ± 10). MRI indices of donor site healing were not different between treatment groups ( P = .53-.90).

CONCLUSION

Whether randomized to receive PRP in their patellar defect or not, patients continued to have similar levels of kneeling pain and patellar defect sizes after autograft BPTB ACL reconstruction. Registration: NCT01765712 ( ClinicalTrials.gov identifier).

Tomographic Study of Femoral Positioning in Anterior Cruciate Ligament Reconstruction Using the Transtibial Technique

Purpose

To analyze the location of the femoral tunnel by three-dimensional computed tomography (3D CT) of the lateral condyle in patients who underwent arthroscopic single-bundle anterior cruciate ligament (ACL) reconstruction, performed using a modified transtibial technique, and to compare the results with data from the literature.

Materials and Methods

Seventeen patients with ACL lesions underwent modified transtibial ACL reconstruction. Postoperatively, 3D CT examinations were performed and the images were analyzed by the quadrant system described by Bernard and Hertel to define the femoral tunnel coordinates.

Results

The mean value of femoral tunnel location coordinates was 37.1±5.9 in the horizontal plane and 23.9±7.5 in the vertical plane. Compared with other studies using the transtibial or transportal technique, femoral positioning was improved in the vertical plane. The outside-in technique provided the best results both in the vertical and horizontal planes.

Conclusions

The modified transtibial technique was not effective for systematically anatomic femoral tunnel positioning; however, it was relatively better than the conventional transtibial technique.

One stage revision single-bundle anterior cruciate ligament reconstruction with impacted morselized bone graft following a failed double-bundle reconstruction

Although double-bundle anterior cruciate ligament (ACL) reconstruction has theoretical benefits such as more accurate reproduction of ACL anatomy, it is technically more demanding surgery. This report describes the case of a one stage revision single-bundle ACL reconstruction after primary double-bundle ACL reconstruction. A professional dancer had an ACL previously reconstructed with a double-bundle technique, but the femoral tunnels were malpositioned resulting in residual laxity and rotational instability. The previous femoral tunnel positions were vertical and widened. The previous vertical tunnels were filled with impacted bone graft and a revision single-bundle ACL reconstruction was performed via the new femoral tunnel with a 2 O'clock position between the previous two tunnels. After 10 months of postoperative rehabilitation, the patient returned to professional dancing with sound bony union and without any residual instability.

Synovial C-Shaped Tibial Footprint of the Anterior Cruciate Ligament

Background:

Although numerous anatomic studies about the anterior cruciate ligament (ACL) structure and attachments have been performed, these studies have not reached consensus on the ACL footprint.

Purpose:

To investigate the existing controversy regarding the morphology of the tibial ACL insertion (footprint) and confirm histologically that the tibial ACL footprint is not completely filled with ligament tissue.

Study Design:

Descriptive laboratory study.

Methods:

The tibial ACL footprint was dissected from 20 different fresh-frozen cadaveric knees (all males; mean age, 68.8 ± 5.4 years [range, 55-80 years]; mean weight, 78 ± 6.6 kg [range, 45-93 kg]). Two knees, 1 with severe osteoarthritis and 1 with previous knee surgery, were excluded. The tibial ACL insertion was observed, and this area was longitudinally divided into 4 parallel slices (0%-25%, 25-50%, 50%-75%, and 75%-100%), embedded in paraffin wax, and stained with hematoxylin-eosin, alcian blue, and picrosirius-polarization. The specimens were measured using a microscope to determine the distances from the anterior to the posterior border of the ACL ligament tibial insertion and the distance from the posterior border to the end of the ligament fibers of the ACL ligament tibial insertions.

Results:

The 18 evaluated knee specimens confirmed the finding of a C-shaped tibial insertion of the ACL. The measurements showed that the ligament (vertical parallel collagen fibers) occupied only 30.8% of the complete insertion. The remaining area was filled with synovial tissue, demonstrating histologically the “C” shape.

Conclusion:

This study confirms macroscopically the C-shaped tibial insertion of the ACL and shows histologically that synovial tissue is an indirect insertion filling the major part of the footprint.

Clinical Relevance:

This anatomic study suggests a different shape of the ACL tibial footprint, which may be useful for new perspectives regarding ACL reconstruction surgery research.

Arthroscopically blind anatomical anterior cruciate ligament reconstruction using only navigation guidance: a cadaveric study

BACKGROUND

To develop a preoperative planning and navigation system for anatomic anterior cruciate ligament (ACL) reconstruction and to evaluate the accuracy and the efficacy of anatomical ACL reconstruction using only navigation guidance.

METHODS

A three-dimensional (3D) preoperative planning and navigation system was developed from open source libraries. Twenty knees from 10 fresh-frozen human cadavers underwent navigation-only guided double-bundle ACL reconstruction using the transportal technique. A computed tomography (CT) scan was performed after ACL reconstruction to create a 3D surface model of the distal femur. We evaluated the tunnel position by Bernard's quadrant method, the tunnel orientation by measuring the tunnel angle in three projected planes, and the incidence of posterior cortical damage. Then, we compared preoperative planning with the postoperative results.

RESULTS

The difference in tunnel position between preoperative planning and the postoperative results was a mean of 2.50±1.75mm (range, 0.77 to 5.85mm) in the anteromedial (AM) tunnel and a mean of 3.53±2.20mm (range, 0.39 to 7.92mm) in the posterolateral (PL) tunnel. The difference in tunnel orientation was a mean of 6.74±6.70° (range, 0.35 to 25.6°) in the AM tunnel and a mean of 5.73±3.51° (range, 1.58 to 15.04°) in the PL tunnel. No statically significant difference was observed. Posterior cortical damage developed in seven cases (35%).

CONCLUSIONS

Our navigation-only guided ACL reconstruction produced consistent femoral tunnel position and orientation results. The accuracy and consistency of femoral tunneling were improved by using the preoperative planning and navigation system.

Predictors of Revision Surgery After Primary Anterior Cruciate Ligament Reconstruction

Background:

Revision anterior cruciate ligament (ACL) reconstruction surgery occurs in 5% to 15% of individuals undergoing ACL reconstruction. Identifying predictors for revision ACL surgery is of essence in the pursuit of creating adequate prevention programs and to identify individuals at risk for reinjury and revision.

Purpose:

To determine predictors of revision ACL surgery after failed primary ACL reconstruction.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

A total of 251 participants (mean age ± SD, 26.1 ± 9.9 years) who had undergone primary ACL reconstruction 1 to 5 years earlier completed a comprehensive survey to determine predictors of revision ACL surgery at a mean 3.4 ± 1.3 years after the primary ACL reconstruction. Potential predictors that were assessed included subject characteristics (age at the time of surgery, time from injury to surgery, sex, body mass index, preinjury activity level, return to sport status), details of the initial injury (mechanism; concomitant injury to other ligaments, menisci, and cartilage), surgical details of the primary reconstruction (Lachman and pivot shift tests under anesthesia, graft type, femoral drilling technique, reconstruction technique), and postoperative course (length of rehabilitation, complications). Univariate and multivariate logistic regression analyses were performed to identify factors that predicted the need for revision ACL surgery.

Results:

Overall, 21 (8.4%) subjects underwent revision ACL surgery. Univariate analysis showed that younger age at the time of surgery (P = .003), participation in sports at a competitive level (P = .023), and double-bundle ACL reconstruction (P = .024) predicted increased risk of revision ACL surgery. Allograft reconstructions also demonstrated a trend toward greater risk of revision ACL surgery (P = .076). No other variables were significantly associated with revision ACL surgery. Multivariate analysis revealed that revision ACL surgery was only predicted by age at the time of surgery and graft type (autograft vs allograft).

Conclusion:

The overall revision ACL surgery rate after primary unilateral ACL reconstruction was 8.4%. Univariate predictors of revision ACL reconstruction included younger age at the time of surgery, competitive baseline activity level, and double-bundle ACL reconstruction. However, multivariable logistic regression analysis indicated that age and reconstruction performed with allograft were the only independent predictors of revision ACL reconstruction.

A Comparison between Clinical Results of Selective Bundle and Double Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

The purpose of this study was to compare the clinical outcomes of arthroscopic anatomical double bundle (DB) anterior cruciate ligament (ACL) reconstruction with either selective anteromedial (AM) or posterolateral (PL) bundle reconstruction while preserving a relatively healthy ACL bundle.

MATERIALS AND METHODS

The authors evaluated 98 patients with a mean follow-up of 30.8±4.0 months who had undergone DB or selective bundle ACL reconstructions. Of these, 34 cases underwent DB ACL reconstruction (group A), 34 underwent selective AM bundle reconstruction (group B), and 30 underwent selective PL bundle reconstructions (group C). These groups were compared with respect to Lysholm and International Knee Documentation Committee (IKDC) score, side-to-side differences of anterior laxity measured by KT-2000 arthrometer at 30 lbs, and stress radiography and Lachman and pivot shift test results. Pre- and post-operative data were objectively evaluated using a statistical approach.

RESULTS

The preoperative anterior instability measured by manual stress radiography at 90° of knee flexion in group A was significantly greater than that in groups B and C (all p<0.001). At last follow-up, mean side-to-side instrumented laxities measured by the KT-2000 and manual stress radiography were significantly improved from preoperative data in all groups (all p<0.001). There were no significant differences between the three groups in anterior instability measured by KT-2000 arthrometer, pivot shift, or functional scores.

CONCLUSION

Selective bundle reconstruction in partial ACL tears offers comparable clinical results to DB reconstruction in complete ACL tears.

The anatomy of the anterior cruciate ligament and its relevance to the technique of reconstruction

Anterior cruciate ligament (ACL) reconstruction is commonly performed and has been for many years. Despite this, the technical details related to ACL anatomy, such as tunnel placement, are still a topic for debate. In this paper, we introduce the flat ribbon concept of the anatomy of the ACL, and its relevance to clinical practice.

Cite this article: Bone Joint J 2016;98-B:1020–6.

Rolled knitted scaffolds based on PLA-pluronic copolymers for anterior cruciate ligament reinforcement: A step by step conception

The aim of this study was to prepare a new knitted scaffold from PLA-Pluronic block copolymers for anterior cruciate ligament reconstruction. The impact of sterilization methods (beta-ray and gamma-ray sterilization) on copolymers was first evaluated in order to take into account the possible damages due to the sterilization process. Beta-ray radiation did not significantly change mechanical properties in contrast to gamma-ray sterilization. It was shown that ACL cells proliferate onto these copolymers, demonstrating their cytocompatibility. Thirdly, in order to study the influence of shaping on mechanical properties, several shapes were created with copolymers yarns: braids, ropes and linear or rolled knitted scaffolds. The rolled knitted scaffold presented interesting mechanical characteristics, similar to native anterior cruciate ligament (ACL) with a 67 MPa Young's Modulus and a stress at failure of 22.5 MPa. These findings suggest that this three dimensional rolled knitted scaffold meet the mechanical properties of ligament tissues and could be suitable as a scaffold for ligament reconstruction. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 735-743, 2017.

Comparison of Femoral Tunnel Length and Obliquity Between Transtibial, Anteromedial Portal, and Outside-In Surgical Techniques in Single-Bundle Anterior Cruciate Ligament Reconstruction: A Meta-analysis

PURPOSE

It is unclear whether femoral tunnel length and obliquity differ after transtibial and independent femoral drilling techniques of anterior cruciate ligament (ACL) reconstruction. This meta-analysis therefore compared femoral tunnel length and obliquity in patients who underwent ACL reconstruction by the transtibial, anteromedial (AM) portal, and outside-in (OI) techniques.

METHODS

In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, all studies comparing femoral tunnel length and obliquity with various measurement tools-from direct measurement to imaging methods such as plain radiography, computed tomography, or magnetic resonance imaging-in patients who underwent reconstruction by the transtibial or independent femoral drilling (AM portal or OI) techniques were included.

RESULTS

Fourteen studies were included in the meta-analysis. The femoral tunnel length was 7.8 to 11.0 mm longer (P < .05) and coronal obliquity was 7.5° to 29.1° more vertical (P < .05) with the transtibial technique than with the AM portal or OI technique. Femoral tunnel and graft obliquity in the sagittal plane, however, did not differ significantly (P > .05).

CONCLUSIONS

ACL reconstruction using the AM portal and OI femoral drilling techniques resulted in a shorter length and greater coronal obliquity of the femoral tunnel than did the transtibial technique. However, these 3 femoral drilling techniques resulted in similar obliquities of the femoral tunnel and graft in the sagittal plane.

LEVEL OF EVIDENCE

Level III, meta-analysis.

Technique of anatomical single bundle ACL reconstruction with rounded rectangle femoral dilator

BACKGROUND

This study aimed to present a new technique for anatomical single bundle anterior cruciate ligament (ACL) reconstruction. We developed an original rounded rectangular dilator set to create rounded rectangular femoral tunnels. This technique can increase the femoral tunnel size without roof impingement, and has the potential to reduce the graft failure rate. We investigated the tunnel position and the incidence of intraoperative complications.

METHOD

The presented technique is anatomical single bundle ACL reconstruction using a semitendinosus graft (with or without the gracilis tendon). The tunnel was drilled via an additional medial portal. Rounded rectangular tunnels were created using a special dilator. Tibial tunnels were created using conventional rounded tunnels. Fixation was achieved using a suspensory device on the femoral side and a plate and screw on the tibial side.

PATIENTS

Fifty patients underwent this surgery, and intraoperative complications were investigated. The femoral tunnel positions were documented postoperatively from computed tomography scans using the quadrant method. The tibial tunnel positions (anterior-to-posterior, medial-to-lateral) were documented using intraoperative X-ray scans.

RESULTS

Only one patient had a partial posterior tunnel wall blowout. The femoral tunnel length varied between 30 and 40mm (mean, 34.9±3.3mm). All femoral and tibial tunnels were located within the area of the anatomical ACL insertions.

CONCLUSION

We did not experience any serious intraoperative complications during anatomical single bundle ACL reconstruction using a rounded rectangle dilator, and the resulting locations of the femoral and tibial tunnels were within the anatomical ACL footprint.

LEVEL OF EVIDENCE

Level IV.

Biomechanical evaluation of knee kinematics after anatomic single- and anatomic double-bundle ACL reconstructions with medial meniscal repair

PURPOSE

To evaluate knee laxity after anatomic ACL reconstruction with additional suture repair of a medial meniscus tear.

METHODS

Kinematics of the intact knee were determined in 12 human cadaver specimens in response to a 134-N anterior tibial load (aTT) and a combined rotatory load of 10 Nm valgus and 4 Nm internal tibial rotation (aTTPS) using a robotic/universal force moment sensor testing system. Subsequently, the ACL was resected following the creation of a standardized tear of the medial meniscus, a standard meniscus repair and an ACL reconstruction using an anatomic single-bundle (6) or an anatomic double-bundle technique (6). Knee kinematics were determined following every sub-step.

RESULTS

Significant increase of aTT in the ACL-deficient knee was found (p ≤ 0.001) with a further increase in the ACL-deficient knee with additional medial meniscal rupture (p ≤ 0.001). ACL reconstructions significantly decreased aTT compared with the ACL and meniscus-ruptured knee. No significant differences were seen between the intact knee and the ACL-reconstructed knee with additional meniscal repair (p < 0.05). In response to a simulated pivot shift, aTTPS in the intact knee significantly increased in the ACL-deficient knee and meniscus-ruptured knee (p = 0.005). No significant differences in knee kinematics were found between SB as well as DB ACL reconstruction with additional medial meniscal repair compared with the intact knee. Comparison of SB versus DB ACL reconstruction did not reveal any significant differences in a simulated Lachman test or simulated pivot shift test (n.s.).

CONCLUSIONS

aTT as well as aTTPS significantly increased with ACL deficiency compared with the intact knee; additional medial meniscal rupture further increased aTT. Anatomic ACL reconstruction with medial meniscal repair did not reveal significant differences in knee kinematics compared with the intact knee. Comparison of anatomic SB versus DB ACL reconstruction with additional repair of the medial meniscus did not show significant differences neither in a simulated Lachman nor in a simulated pivot shift test.

Outcome of Single-Bundle Hamstring Anterior Cruciate Ligament Reconstruction Using the Anteromedial Versus the Transtibial Technique: A Systematic Review and Meta-analysis

PURPOSE

To compare the clinical outcomes of single-bundle hamstring anterior cruciate ligament (ACL) reconstruction between the anteromedial (AM) and transtibial (TT) techniques.

METHODS

We performed a comprehensive systematic review and meta-analysis of the English-language literature in the PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials databases for articles that compared clinical outcomes of AM versus TT ACL reconstruction. The outcome measures analyzed included postoperative Lachman test, pivot-shift test, International Knee Documentation Committee (IKDC), and Lysholm scores.

RESULTS

We included 10 articles from an initial 308 abstracts for the systematic review and included 6 studies for the meta-analysis. The study population consisted of a total of 733 patients, of whom 366 (49.9%) underwent the AM technique and 367 (50.1%) underwent the TT technique for ACL reconstruction. For postoperative knee stability, the AM technique yielded superior results in terms of the proportion of negative Lachman test results (n = 243; odds ratio [OR], 2.98 [95% confidence interval (CI), 1.29 to 6.88]) and proportion of negative pivot-shift test results (n = 238; OR, 3.67 [95% CI, 1.80 to 7.52]). For postoperative functional status, the AM technique yielded superior results in terms of objective IKDC grading (proportion with IKDC grade A) (n = 269; OR, 2.19 [95% CI, 1.23 to 3.88]) but had comparable Lysholm scores (n = 478; mean difference, 1.43 [95% CI, 0.01 to 2.84]).

CONCLUSIONS

Single-bundle hamstring ACL reconstruction using the AM technique showed superior surgeon-recorded stability according to the IKDC knee score, Lachman test, and pivot-shift test. However, there was no difference in patient-reported functional outcome (Lysholm score).

LEVEL OF EVIDENCE

Level III, systematic review and meta-analysis of Level I, II, and III studies.

Femoral footprint variation of the posterolateral bundle of the anterior cruciate ligament and double-bundle reconstruction

BACKGROUND

The study is aimed to observe the range of variation of the ACL PLB femoral footprint and investigate countermeasures for accurate femoral bone tunnel placement during double-bundle ACL reconstruction.

METHODS

The femoral insertions of the anteromedial bundle (AMB) and PLB of the ACL were dissected in 30 male cadaveric knees. The ACL footprint on the lateral intercondylar wall (LIW) was observed, and the shape of the LIW, the resident ridge, the angle between the ACL long axis and femoral axis (AA), and the vertical distance from the center of the PLB to the lowest cartilage border of the LIW (PD) were measured.

RESULTS

The area most populated by the ACL fibers was directly under the resident ridge. AA = 18.7°±15.25° with variation from -18° to 56°, and PD=7.02±1.47 mm with variation from 3.75 to 11.08 mm. Both discrete values were very large in both groups of data. There were two kinds of LIW: trapezoidal (8 knees) and triangular (21 knees). Both AA and PD values exhibited significant differences between the two types of LIWs (P=0.00).

CONCLUSION

AA and PD vary among individuals. The insertions and centers of the PLB cannot be exactly anatomically determined with one size. For double-bundle ACL reconstruction, an individualized intraoperative footprint observation for fresh cases with footprint remnants, or resident ridge and anteromedial bundle-interval identification for old ACL tears, can be reasonable methods for posterolateral tunnel orientation.

CLINICAL RELEVANCE

Clinical relevance is observe the range of variation of the PLB femoral footprint for clinical double-bundle ACL reconstruction.

PRP Augmentation for ACL Reconstruction

Current research is investigating new methods to enhance tissue healing to speed up recovery time and decrease the risk of failure in Anterior Cruciate Ligament (ACL) reconstructive surgery. Biological augmentation is one of the most exploited strategies, in particular the application of Platelet Rich Plasma (PRP). Aim of the present paper is to systematically review all the preclinical and clinical papers dealing with the application of PRP as a biological enhancer during ACL reconstructive surgery. Thirty-two studies were included in the present review. The analysis of the preclinical evidence revealed that PRP was able to improve the healing potential of the tendinous graft both in terms of histological and biomechanical performance. Looking at the available clinical evidence, results were not univocal. PRP administration proved to be a safe procedure and there were some evidences that it could favor the donor site healing in case of ACL reconstruction with patellar tendon graft and positively contribute to graft maturation over time, whereas the majority of the papers did not show beneficial effects in terms of bony tunnels/graft area integration. Furthermore, PRP augmentation did not provide superior functional results at short term evaluation.

Outcome of anatomical double-bundle ACL reconstruction using hamstring tendons via an outside-in approach

PURPOSE

To evaluate the clinical outcome of anatomical double-bundle anterior cruciate ligament (ACL) reconstruction using multistranded hamstring tendons via an outside-in approach.

METHODS

One hundred and twenty-one patients (mean age 28 ± 10 years) who underwent ACL reconstruction were examined. Using an outside-in femoral drill guide, an upper femoral tunnel for the anteromedial (AM) graft was created just below the superior articular cartilage margin of the medial wall of the lateral condyle through a small incision. A lower femoral tunnel for the posterolateral (PL) graft was drilled in the centre of the inferior-posterior half of the attachment area behind the resident's ridge in the same manner. Two tibial tunnels were created at the centre of the AM and PL bundle footprints of a normal ACL. Patients were evaluated at 24 months postoperatively.

RESULTS

According to the IKDC form, 52 knees (43 %) were graded as normal, 64 (53 %) as nearly normal, 1 (1 %) as abnormal and 4 (3 %) as graft rupture due to re-injury. Loss of knee extension of <5° was observed in one patient (1 %). Among 111 patients who were directly evaluated, none showed loss of flexion of <5°. Lachman sign was negative in 103 patients (93 %), while the pivot shift test result was negative or equivalent to that of the contralateral healthy knee in 103 patients (93 %). The mean side-to-side difference in anterior laxity at manual maximum force with the KT-2000 arthrometer(®) was 0.9 ± 1.1 mm, and 94 % of patients showed a range between -1 and +2 mm.

CONCLUSION

The anatomical double-bundle outside-in ACL reconstruction provided a satisfactory short-term outcome.

LEVEL OF EVIDENCE

Case series, Level IV.

The sagittal plane angle and tunnel-related complications in double-bundle anterior cruciate ligament reconstruction using the transportal technique: an in vivo imaging study

PURPOSE

To evaluate the relation between the tunnel angle in the 3 orthogonal planes, especially the sagittal plane, which can be influenced by knee flexion during drilling, and the incidence of complications from the transportal technique using in vivo imaging data.

METHODS

Fifty-one patients who underwent anatomic double-bundle anterior cruciate ligament reconstruction by the transportal technique were evaluated retrospectively. A 3-dimensional surface model was made using an axial computed tomography scan obtained after anterior cruciate ligament reconstruction. The tunnel length, posterior cortical damage, proximity between the outer orifice of the tunnel and lateral collateral ligament (LCL) origin, and medial femoral condyle cartilage damage were evaluated on a 3-dimensional computed tomography scan and 3-T magnetic resonance imaging. Correlations between those parameters and the tunnel angle in the coronal, axial, and sagittal planes were analyzed.

RESULTS

A tunnel length of less than 30 mm developed in 4 cases (8%) in the anteromedial tunnel and in 1 case (2%) in the posterolateral (PL) tunnel. Posterior cortical damage developed in 12 cases (23%). A distance from the outer orifice of the tunnel to the LCL origin of less than 3 mm occurred in 18 cases (35.2%) in the PL tunnel. Medial femoral condyle cartilage damage was detected in 3 cases (6%). A positive correlation was observed between the sagittal angle and anteromedial tunnel length (P = .002, r = 0.547). The sagittal angle in the group with posterior cortical damage was lower than that in the group with no posterior cortical damage (P = .002). A negative correlation was observed between the distance from the outer orifice of the PL tunnel to the LCL origin and the sagittal angle (P = .002, r = -0.55).

CONCLUSIONS

Drilling at a higher angle in the sagittal plane decreased the incidence of posterior cortical damage and a short anteromedial tunnel. However, drilling at a higher angle shortened the distance to the LCL origin for the PL tunnel.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Flat midsubstance of the anterior cruciate ligament with tibial "C"-shaped insertion site

PURPOSE

This anatomical cadaver study was performed to investigate the flat appearance of the midsubstance shape of the anterior cruciate ligament (ACL) and its tibial "C"-shaped insertion site.

METHODS

The ACL midsubstance and the tibial ACL insertion were dissected in 20 cadaveric knees (n = 6 fresh frozen and n = 14 paraffined). Magnifying spectacles were used for all dissections. Morphometric measurements were performed using callipers and on digital photographs.

RESULTS

In all specimens, the midsubstance of the ACL was flat with a mean width of 9.9 mm, thickness of 3.9 mm and cross-sectional area of 38.7 mm(2). The "direct" "C"-shaped tibial insertion runs from along the medial tibial spine to the anterior aspect of the lateral meniscus. The mean width (length) of the "C" was 12.6 mm, its thickness 3.3 mm and area 31.4 mm(2). The centre of the "C" was the bony insertion of the anterior root of the lateral meniscus overlayed by fat and crossed by the ACL. No posterolateral (PL) inserting ACL fibres were found. Together with the larger "indirect" part (area 79.6 mm(2)), the "direct" one formed a "duck-foot"-shaped footprint.

CONCLUSION

The tibial ACL midsubstance and tibial "C"-shaped insertion are flat and are resembling a "ribbon". The centre of the "C" is the bony insertion of the anterior root of the lateral meniscus. There are no central or PL inserting ACL fibres. Anatomical ACL reconstruction may therefore require a flat graft and a "C"-shaped tibial footprint reconstruction with an anteromedial bone tunnel for single bundle and an additional posteromedial bone tunnel for double bundle.

Ribbon like appearance of the midsubstance fibres of the anterior cruciate ligament close to its femoral insertion site: a cadaveric study including 111 knees

PURPOSE

Recently, the configuration of the anterior cruciate ligament (ACL) from its direct femoral insertion to midsubstance was found to be flat. This might have an important impact for anatomical ACL reconstruction. The purpose of this anatomical study was to evaluate the macroscopic appearance of the ACL from femoral to midsubstance.

METHODS

The ACL was dissected in 111 human fresh frozen cadaver knees from its femoral insertion to midsubstance, and the shape was described. The anatomical findings were documented on digital photographs and on video. Thirty knees were sent for computed tomography (CT), magnetic resonance imaging (MRI) and histology of the femoral ACL insertion.

RESULTS

Two millimetres from its direct femoral insertion, the ACL fibres formed a flat ribbon in all dissected knees without a clear separation between AM and PL bundles. The ribbon was in exact continuity of the posterior femoral cortex. The width of the ribbon was between 11.43 and 16.18 mm and the thickness of the ACL was only 2.54-3.38 mm. 3D CT, MRI and the histological examination confirmed above findings.

CONCLUSION

This is a detailed anatomical study describing the ribbon-like structure of the ACL from its femoral insertion to midsubstance. A key point was to carefully remove the surface fibrous membrane of the ACL. A total of 2-3 mm from its bony femoral insertion, the ACL formed a flat ribbon without a clear separation between AM and PL bundles. The ribbon was in exact continuity of the posterior femoral cortex. The findings of a flat ligament may change the future approach to femoral ACL footprint and midsubstance ACL reconstruction and to graft selection.

Adolescent differences in knee stability following computer-assisted anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) surgery is being increasingly performed in the adolescent population. Computer navigation offers a reliable way to quantitatively measure knee stability during ACL reconstruction. A retrospective review of all adolescent patients (<18 years old) who underwent computer-assisted primary single bundle ACL reconstruction by a single surgeon from 2007 to 2012 was performed. The average age was 15.8 years (SD 3.3). Female adolescents were found to have higher internal rotation than male adolescents both pre- (25.6° vs 21.7°, P=0.026) and post-reconstruction (20.1° vs 15.1°, P=0.005). Compared to adults, adolescents demonstrated significantly higher internal rotation both pre- (23.3° vs 21.5°, P=0.047) and post-reconstruction (17.1° vs 14.4°, P=0.003). They also had higher total rotation both pre- (40.9° vs 38.4°, P=0.02) and post-reconstruction when compared to adults (31.56° vs 28.67°, P=0.005). In adolescent patients, anterior translation was corrected more than rotation. Females had higher pre- and residual post-reconstruction internal rotation compared to males. When compared to adults, adolescents had increased internal rotation and total rotation both pre-and post-reconstruction.