Femoral and tibial graft tunnel parameters after transtibial, anteromedial portal, and outside-in single-bundle anterior cruciate ligament reconstruction

Race and Gender Differences in Anterior Cruciate Ligament Femoral Footprint Location and Orientation: A 3D-MRI Study

OBJECTIVE

The femoral tunnel position is crucial to anatomic single-bundle anterior cruciate ligament (ACL) reconstruction, but the ideal femoral footprint position are mostly based on small-sized cadaveric studies and elderly patients with a single ethnic background. This study aimed to identify potential race- or gender-specific differences in the ACL femoral footprint location and ACL orientation, determine the correlation between the ACL orientation and the femoral footprint location.

METHODS

Magnetic resonance images (MRIs) of 90 Caucasian participants and 90 matched Chinese subjects were used for reconstruction of three-dimensional (3D) femur and tibial models. ACL footprints were sketched by several experienced orthopedic surgeons on the MRI photographs. The anatomical coordinate system was applied to reflect the ACL footprint location and orientation of scanned samples. The femoral ACL footprint locations were represented by their distance from the origin in the anteroposterior (A/P) and distal-proximal (D/P) directions. The orientation of the ACL was described with the sagittal, coronal and transverse deviation angles. The ACL orientation and femoral footprint position were compared by the two-sided t-test. Multiple regression analysis was used to study the correlation between the orientation and femoral footprint position.

RESULTS

The average femur footprint A/P position was -6.6 ± 1.6 mm in the Chinese group and -5.1 ± 2.3 mm in the Caucasian group, (p < 0.001). The average femur footprint D/P position was -2.8 ± 2.4 mm in Chinese and - 3.9 ± 2.0 mm in Caucasians, (p = 0.001). The Chinese group had a mean difference of a 1.5 mm (6.1%) more posterior and 1.1 mm (5.3%) more proximal in the position from the flexion-extension axis (FEA). And the males have a sagittal plane elevation about 4-5° higher than females in both racial groups. Furthermore, for every 1% (0.40 mm) increase in A/P and D/P values, the sagittal angle decreased by about 0.12° and 0.24°, respectively; the coronal angle decreased by about 0.10° and 0.30°, respectively. For every 1% (0.40 mm) increase in D/P value, the transverse angle increased by about 0.14°.

CONCLUSION

The significant race- and gender-specific differences in the femoral footprint and orientation of the ACL should be taken in consideration during anatomic single-bundle ACL reconstruction. Furthermore, the quantitative relationship between the ACL orientation and the footprint location might provide some reference for surgeons to develop a surgical strategy in ACL single-bundle reconstruction and revision.

Research progress on preparation of lateral femoral tunnel and graft fixation in anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) injury is one of the most common types of sports injuries. People's need to participate in sports and desire for a high quality of life promotes the continuous development of ACL reconstruction technology. Arthroscopic ACL reconstruction has been recognized as an effective method for the treatment of ACL injuries. This review analyses and summarizes the advantages and limitations of each surgical procedure for arthroscopic ACL reconstruction reported in the relevant literature so as to promote the future development of more relevant techniques.

Influence of knee flexion angle on graft bending angle during anterior cruciate ligament reconstruction using the transportal technique

This study aimed to examine change in the graft bending angle (GBA) according to various knee flexion angles in creating femoral tunnel by the transportal technique in ACL reconstruction, and to reveal knee flexion angle minimizing GBA while maintaining stable femoral tunnel characteristics. Patients who underwent ACL reconstruction using the transportal technique between January 2017 and December 2018 were retrospectively reviewed. Patients were classified into three groups according to knee flexion angle when creating femoral tunnel (group 1: < 120° (n = 19); group 2: 120-129° (n = 32); group 3: ≥ 130° (n = 33). GBA was measured on three-dimensional knee model reconstructed from postoperative computed tomography images. The length of the femoral tunnel and posterior wall blow-out were also checked. There was significant difference of GBA between the groups (group 1 = 112.1°; group 2 = 106.4°; group 3 = 101.4°, p < 0.001). The knee flexion angle in creating femoral tunnel was negatively correlated with GBA (r = - 0.733, p < 0.001). Five patients in group 1 had short femoral tunnel. GBA was influenced by knee flexion angle in creating femoral tunnel and got more acute as the knee flexion angle increased. Considering length and risk of wall blow-out in femoral tunnel, and GBA, knee flexion angle between 120 and 130° could be recommended as appropriate angle to create optimal femoral tunnel in ACL reconstruction using the transportal technique.

Accuracy of Femoral Tunnel Placement between Anteromedial and Anterolateral Visualisation Portals in Anterior Cruciate Ligament Reconstruction - Outcomes of a CT based Cross-Sectional Study

Introduction

Anatomical femoral tunnel placement is critical for anterior cruciate ligament reconstruction (ACLR). Tunnel placement may vary with different surgical techniques. The aim of this study was to compare the accuracy of femoral tunnel placement between the Anteromedial (AM) and Anterolateral (AL) visualisation portals on post-operative CT scans among a cohort of ACLR patients.

Materials and methods

This cross-sectional study was conducted from January 2018 to March 2020 after obtaining ethics clearance. Patients who went for arthroscopic ACLR in our institute were divided into an AM (group 1) and an AL (group 2) based on the visualisation portal for creating the femoral tunnel and a 3D CT scan was done. The femoral tunnel position was calculated in deep to shallow and high to low direction using the Bernard Hertel grid. Femoral tunnel angle was measured in the 2D coronal image. Statistical analysis was done with the data collected.

Results

Fifty patients with an average age of 26.36 (18-55) years ±7.216 SD were enrolled in the study. In this study, the AM technique was significantly more accurate (p<0.01) than the AL technique in terms of femoral tunnel angle. Furthermore, the deep to the shallow position was significantly (p= 0.018) closer to normative values, as determined by the chi-square test. The chances of error in tunnel angle in femoral condyle are 2.6 times greater in the AL technique (minimal clinical difference).

Conclusion

To conclude, in ACLR the anteromedial visualisation portal can facilitate accurate femoral tunnel placement compared to the anterolateral visualisation portal.

Remnant Preservation of the Primary Vertical Graft in Revision Anterior Cruciate Ligament Reconstruction

Background

The remnant preservation of a primary vertical graft in revision anterior cruciate ligament reconstruction (ACLR) can benefit anteroposterior stability. However, studies that address this concept are rare.

Purpose

To evaluate clinical outcomes of remnant preservation of primary vertical graft in revision ACLR.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 74 patients with revision ACLR were included in this retrospective study. Remnant preservation revision ACLR was performed only in patients with primary vertical grafts. The patients were divided into 2 groups according to whether the primary remnant vertical graft was preserved (remnant group; n = 48) or absent or sacrificed (no-remnant group; n = 26). The remnant group was further divided according to the degree of remnant tissue: sufficiently preserved subgroup (graft coverage, ≥50%; n = 25) and insufficiently preserved subgroup (graft coverage, <50%; n = 23). Clinical outcomes were evaluated using the International Knee Documentation Committee (IKDC) subjective form, Lysholm score, Tegner activity scale, manual laxity tests, and side-to-side difference in anterior tibial translation on Telos stress radiographs.

Results

The mean time to final follow-up was 40.7 ± 16.8 months. The remnant group showed more improved results in the postoperative Lachman test and Telos side-to-side difference than did the no-remnant group (P = .017 and .016, respectively). The post hoc test revealed that the side-to-side difference in laxity in the sufficiently preserved subgroup significantly outperformed that in the no-remnant group (P = .001), although no significant difference existed between the insufficiently preserved and no-remnant subgroups (P = .850). The postoperative IKDC subjective form, Lysholm score, and Tegner activity scale did not show significant differences between the 2 groups (P = .480, .277, and .883, respectively).

Conclusion

The remnant preservation of the primary vertical graft in revision ACLR may result in better anteroposterior stability. However, subjective outcomes in the remnant group did not exceed that of the no-remnant group. The subgroup analysis revealed that only sufficiently preserved remnants demonstrated better anteroposterior stability.

Clinical outcome of anterior cruciate ligament reconstruction with modified transtibial and anteromedial portal

Arthroscopic ACL reconstruction is the current standard care of treatment for anterior cruciate ligament (ACL) injuries. Modified transtibial (mTT) and anteromedial portal (AMP) techniques aim at the anatomical placement of femoral tunnel. Controversy existed in the literature with regard to the outcome of these techniques. Hence, we designed a retrospective comparative study to analyse the clinical and functional outcomes of mTT and AMP techniques. We hypothesized that there would be no difference between the clinical and functional outcomes in mTT and AMP techniques. This retrospective observational study was conducted in consecutive patients who underwent arthroscopic ACL reconstruction using semitendinosus-gracilis (STG) quadrupled graft in our tertiary care centre with a minimum follow-up of two years. Out of 69 patients, 37 had undergone ACL reconstruction by mTT technique and remaining by AMP technique. All the patients were assessed clinically by anterior drawer, Lachman's, pivot shift and single-legged hop test. Lysholm Knee Scoring Scale and International Knee Documentation Committee (IKDC) subjective knee evaluation score were used for the functional status. Knee instability was assessed objectively by KT-1000 arthrometer. There was no statistically significant difference in baseline demographic characteristics between mTT and AMP groups. At the end of 2 years, no statistically significant difference was noted in the anterior drawer and Lachman's test. Though not significant, IKDC scores and Lysholm's scores showed a better outcome in the AMP group when compared to the mTT group. AMP group showed significantly better outcome with KT-1000 arthrometer. Based on the results obtained, we presume that overall both mTT and AMP have similar functional outcome. However, as AMP technique offers significantly improved subjective rotational stability on pivot shift test, better hop limb symmetry index and KT 1000 readings compared to mTT, we suggest AMP over mTT.

Anatomical double-bundle anterior cruciate ligament reconstruction moderately improved tegner scores over the long-term: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

To assess the effects of anatomical double-bundle (DB) versus single-bundle (SB) for anterior cruciate ligament (ACL) reconstruction in skeletally mature patients with ACL injuries.

METHODS

MEDLINE, EMBASE, and CENTRAL were searched from inception to February 7, 2022 were screened for randomized controlled trials. The Anatomic Anterior Cruciate Ligament Reconstruction Checklist was used to categorize studies as anatomic. A random-effects meta-analysis was conducted, with pooled results being summarized using mean difference (MD). Risk of Bias (RoB) was assessed using the RoB 2.0 tool. Certainty of evidence was rated using GRADE.

RESULTS

A search of 1371 unique articles yielded eight eligible trials, representing 735 patients (360 DB, 375 SB) with mean (SD) age of 28.5 (2.86) years and follow-up of 52.1 (36.2) months. Most trials had moderate to low RoB. Overall, DB was not significantly better than SB on Lysholm scores (MD = 0.52, 95% CI, - 1.80-2.85, p = 0.66; moderate certainty) or subjective International Knee Documentation Committee (IKDC) scores (MD = - 0.40, 95% CI, - 4.35-3.55, p = 0.84; moderate certainty). Tegner scores were significantly higher in SB than DB in the intermediate term (MD = - 0.72, 95% CI, - 1.10 to - 0.34, p = 0.0002; high certainty), while significantly higher in DB relative to SB in the long-term (MD = 0.52, 95% CI, 0.02-1.03, p = 0.04; high certainty).

CONCLUSION

DB ACL reconstruction significantly improves Tegner scores relative to SB ACL reconstruction over the long-term (t ≥ 5 years). Intermediate term Tegner scores favour SB reconstruction. In both durations, there was no clinically significant difference based on the pre-specified minimal clinically important difference of 1.0 point. There were also no significant differences in IKDC or Lysholm scores. Surgeons should consider anatomical DB ACL reconstruction as a result of long-term improvement in patient-reported outcomes.

LEVEL OF EVIDENCE

I.

Biomechanical Analysis of Ideal Knee Flexion Angle for ACL Graft Tensioning Utilizing Multiple Femoral and Tibial Tunnel Locations

Anterior cruciate ligament (ACL) graft failure rate has been reported to be greater than 5% at 5 years. Our study evaluated ACL excursion with anatomic and nonanatomic femoral and tibial tunnels to determine optimal flexion angle to tension the ACL to minimize excursion. Ten cadaveric knee specimens were used. The ACL was sectioned and the femoral and tibial attachments were marked. A 1/16-inch drill created a tunnel in the center of the ACL footprint on the tibia and femur and additional tunnels were made 5 mm from this. A suture was passed through each tunnel combination and attached to a string potentiometer. The knee was ranged from full extension to 120 degrees of flexion for 10 cycles while mounted in a custom fixture. The change in length (excursion) of the suture during movement was recorded for each combination of femoral and tibial tunnels. Anatomic reconstruction of the ACL with tunnel placement in the center of the femoral and tibial footprint did not result in an isometric graft, with excursion of the ACL during knee motion of 7.46 mm (standard deviation [SD]: 2.7mm), greatest at 2.84 degrees of flexion (SD: 4.22). The tunnel combination that resulted in the least excursion was a femoral footprint 5 mm anterior to the femoral and 5 mm posterior to the tibial footprint (4. 2mm, SD: 1.37 mm). The tunnel combination that resulted in the most excursion utilized femoral footprint 5 mm proximal to the femoral and 5 mm posterior to the tibial footprint (9.81 mm, SD: 2.68 mm). Anatomic ACL reconstruction results in significant excursion of the ACL throughout motion. If not tensioned properly, the ACL can stretch during range of motion, potentially leading to rerupture. To prevent stretching of the graft, the current biomechanical study recommends tensioning an anatomic ACL reconstruction at its point of maximal excursion, or between 0 and 5 degrees of flexion. The level of evidence is IV.

Transtibial Versus Anteromedial Portal Technique for Femoral Tunnel Drilling in Primary Single-Bundle Anterior Cruciate Ligament Reconstruction: A Meta-analysis of Level 1 and 2 Evidence of Clinical, Revision, and Radiological Outcomes

BACKGROUND

Although numerous clinical studies have compared transtibial (TT) and anteromedial portal (AMP) drilling of femoral tunnels during anterior cruciate ligament reconstruction (ACLR), there is no high-quality, evidence-based consensus regarding which technique affords the best outcome.

HYPOTHESIS

There would be no difference between the TT and AMP techniques in terms of knee stability, patient-reported outcomes, incidence of revision, and radiological results.

STUDY DESIGN

Meta-analysis; Level of evidence, 2.

METHODS

The PubMed and EMBASE databases were searched from inception to February 1, 2021. Level 1 and 2 clinical trials that compared TT and AM techniques were included. Data were meta-analyzed for the outcome measures of knee stability, patient-reported functional outcomes, incidence of revision, and radiological results. Dichotomous variables were presented as odds ratios (ORs), and continuous variables were presented as mean differences (MDs) and standard mean differences (SMDs).

RESULTS

The meta-analysis included 18 clinical studies, level of evidence 1 or 2, that involved 53,888 patients. Pooled data showed that the AMP group had a lower side-to-side difference (SMD, 0.22; 95% CI, 0.06 to 0.39; P = .009), a lower incidence of pivot-shift phenomenon (OR, 3.69; 95% CI, 1.26 to 10.79; P = .02), and a higher postoperative Lysholm score (SMD, -0.26; 95% CI, -0.44 to -0.08; P = .005) than the TT group. However, no statistically significant differences were seen in other outcomes, including subjective International Knee Documentation Committee scores (SMD, -0.11; 95% CI, -0.30 to 0.09; P = .30) or grades (OR, 0.93; 95% CI, 0.35 to 2.49; P = .89), postoperative activity level (MD, -0.14; 95% CI, -0.42 to 0.15; P = .35), and incidence of revision ACLR (OR, 1.04; 95% CI, 0.93 to 1.16; P = .45). The TT technique was more likely to create longer (SMD, 1.05; 95% CI, 0.05 to 2.06; P = .04) and more oblique (SMD, 0.81; 95% CI, 0.51 to 1.11; P < .001) femoral tunnels than the AMP technique, and a higher height ratio of the aperture position was detected with the TT technique (SMD, -3.51; 95% CI, -5.54 to -1.49; P < .001).

CONCLUSION

The AMP technique for ACLR may be more likely to produce better knee stability and improved clinical outcomes than the TT technique, but no difference was found in the incidence of revision between the 2 groups.

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

PURPOSE

To compare the postoperative outcomes of 4 different femoral drilling techniques in anterior cruciate ligament reconstruction.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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 OF EVIDENCE

Level II, meta-analysis of Level I and II studies.

Complications following all-inside anterior cruciate ligament reconstruction

PURPOSE

We conducted a comprehensive analysis of possible perioperative complications following all-inside anterior cruciate ligament reconstruction (ACLR). Additional techniques and tips are proposed to prevent and manage complications.

METHODS

Complications following all-inside ACLR performed between December 2015 and December 2020 were retrospectively analysed. Altogether, 348 operations were performed and 275 patients were enrolled with a minimum 12-month follow-up period. Only semitendinosus autograft was utilised in most patients, and semitendinosus-gracilis autograft and allograft were used in five and 31 patients, respectively. Simultaneous meniscal repair, partial meniscectomy, and chondral surgery were performed in 29.5%, 21.1%, and 4.4% of patients, respectively. Complications were observed based on the patient's clinical condition, plain film, and magnetic resonance imaging. Clinical outcomes were assessed pre-operatively and at 12 months post-operatively, using the International Knee Documentation Committee form, Lysholm and Tegner activity scores, and KT1000 side-to-side difference.

RESULTS

Intraoperative and post-operative complications developed in 65 patients (23.6%). The most common complication was cortical button malposition on the femoral side (19.3%). Intra-operative breakage of the retrograde drill was found in two cases (0.73%), with three cases (1.1%) of over-drilling with destruction of the outer cortex. Post-operatively, four (1.5%), 13 (4.7%), and 16 (5.8%) cases of infection, full-thickness re-rupture, and loss of extension, respectively, were recorded. Functional outcome scales showed significant post-operative improvement.

CONCLUSION

Cortical button malposition was the most common but easily preventable complication. All-inside ACLR could be safe and promising after the suggested additional operative techniques and proper perioperative management which decrease complication rates and improve favourable outcomes.

Analysis the Lateral Tunnel Position of the Bone Graft and Regeneration of Femur by CT Tunnel Localization

Objective: To analyze, in a retrospective study, the lateral tunnel position of the graft femur by CT after arthroscopic ACL reconstruction via the anteromedial (AM) approach and the tunnel angle shown on X-ray. Methods and Materials: 60 patients undergoing arthroscopic ACL reconstruction via AM approach with 4 femoral hamstring tendon grafts were investigated from October 2019 to October 2021. Postoperative orthogonal x-rays and computed tomography (CT) scans were obtained, and the position of the femoral tunnel obtained after CT reconstruction was correlated with the Bernard-Hertel grid. The angle of the resulting femoral tunnel on the orthogonal x-ray was analyzed against the CT tunnel position. Results: In the study, the anterior–posterior orientation was forward (P = 0.001) and the high-low orientation was similar (taken as 20%, P = 0.066) or slightly higher (taken as 21%, P = 0.025) compared to the AM beam localization in the two-beam reconstruction. Overall, the femoral tunnel angle on non-weight-bearing orthogonal x-ray was negatively correlated with the anterior–posterior (AP) position of the femoral tunnel centre as shown on CT (P = 0.004, r =−0.368) and positively, but weakly, correlated with the high-low (HL) position (P = 0.049, r = 0.254). Conclusion: Non-weight-bearing orthogonal X-rays only can make approximate predictions about the distribution of anatomical reconstruction, I.D.E.A.L reconstruction.

Influence of the Anteromedial Portal and Transtibial Drilling Technique on Femoral Tunnel Lengths in ACL Reconstruction: Results Using an MRI-Based Model

Background:

In anatomic anterior cruciate ligament (ACL) reconstruction, graft placement through the anteromedial (AM) portal technique requires more horizontal drilling of the femoral tunnel as compared with the transtibial (TT) technique, which may lead to a shorter femoral tunnel and affect graft-to-bone healing. The effect of coronal and sagittal femoral tunnel obliquity angle on femoral tunnel length has not been investigated.

Purpose:

To compare the length of the femoral tunnels created with the TT technique versus the AM portal technique at different coronal and sagittal obliquity angles using the native femoral ACL center as the starting point of the femoral tunnel. The authors also assessed sex-based differences in tunnel lengths.

Study Design:

Descriptive laboratory study.

Methods:

Magnetic resonance imaging scans of 95 knees with an ACL rupture (55 men, 40 women; mean age, 26 years [range, 16-45 years]) were used to create 3-dimensional models of the femur. The femoral tunnel was simulated on each model using the TT and AM portal techniques; for the latter, several coronal and sagittal obliquity angles were simulated (coronal, 30°, 45°, and 60°; sagittal, 45° and 60°), representing the 10:00, 10:30, and 11:00 clockface positions for the right knee. The length of the femoral tunnel was compared between the techniques and between male and female patients.

Results:

The mean ± SD femoral tunnel length with the TT technique was 40.0 ± 6.8 mm. A significantly shorter tunnel was created with the AM portal technique at 30° coronal/45° sagittal (35.5 ± 3.8 mm), whereas a longer tunnel was created at 60° coronal/60° sagittal (53.3 ± 5.3 mm; P < .05 for both). The femoral tunnel created with the AM portal technique at 45° coronal/45° sagittal (40.7 ± 4.8 mm) created a similar tunnel length as the TT technique. For all techniques, the femoral tunnel was significantly shorter in female patients than male patients.

Conclusion:

The coronal and sagittal obliquity angles of the femoral tunnel in ACL reconstruction can significantly affect its length. The femoral tunnel created with the AM portal technique at 45° coronal/45° sagittal was similar to that created with the TT technique.

Clinical Relevance:

Surgeons should be aware of the femoral tunnel shortening with lower coronal obliquity angles, especially in female patients.

Six Percent Incidence of Graft-Tunnel Mismatch in Anatomic Anterior Cruciate Ligament Reconstruction Using Bone-Patella Tendon-Bone Autograft and Anteromedial Portal Drilling

Purpose

The purpose of this study was to determine the incidence of graft-tunnel mismatch (GTM) when performing anatomic anterior cruciate ligament reconstruction (ACLR) using bone-patella tendon-bone (BPTB) grafts and anteromedial portal drilling.

Methods

Beginning in November 2018, 100 consecutive patients who underwent ACLR by two sports fellowship-trained, orthopedic surgeons using BPTB autograft and anteromedial portal drilling were prospectively identified. The BPTB graft dimensions and the femoral tunnel distance, tibial tunnel distance, intra-articular distance, and total distance were measured. Surgeons determined the depth and angle of tunnels based on the patella tendon graft length dimensions in each case. After passage of the graft, the distance from the distal graft tip to the tibial cortex aperture was measured. GTM was defined as the need for additional measures to obtain satisfactory tibial graft fixation (<15–20 mm of bone fixation).

Results

The incidence of mismatch was 6/100 (6%). Five cases involved the graft being too long, with the tibial bone plug protruding excessively from the tibial tunnel—4/5 had a patella tendon length ≥ 50 mm. Three cases were managed with femoral tunnel recession, and two were treated with a free bone plug technique. One patient with a patella tendon length of 35 mm had a graft that was too short, with the tibial bone plug recessed in the tibial tunnel. Of patients whose tibial tunnel distance was within 5 mm of the patella tendon length, only 1/46 (2%) patients had mismatch, whereas 5/54 (9%) of patients who had >5 mm difference had mismatch.

Conclusions

The incidence of graft-tunnel mismatch after anatomic ACLR using BTPB and anteromedial portal drilling in this study is 6%. To limit the occurrence of GTM where the graft is too long, surgeons should drill tibial tunnel distances within 5 mm of the patella tendon length.

Clinical Relevance

The results of this study provide surgeons with a technique of limiting graft tunnel mismatch when performing ACLR using BPTB and anteromedial portal drilling.

Transtibial versus independent femoral tunnel drilling techniques for anterior cruciate ligament reconstruction: evaluation of femoral aperture positioning

Background

Femoral tunnel can be drilled through tibial tunnel (TT), or independent of it (TI) by out-in (OI) technique or by anteromedial (AM) technique. No consensus has been reached on which technique achieves more proper femoral aperture position because there have been evolving concepts in the ideal place for femoral aperture placement. This meta-analysis was performed to analyze the current literature comparing femoral aperture placement by TI versus TT techniques in ACL reconstruction.

Methods

We performed a comprehensive systematic review and meta-analysis of English-language literature in PubMed, Cochrane, and Web of Science databases for articles comparing femoral aperture placement by TI versus TT techniques with aperture position assessed by direct measurement or by postoperative imaging, PXR and/or CT and/or MRI.

Results

We included 55 articles with study population of 2401 knees of whom 1252 underwent TI and 1149 underwent TT techniques. The relevant baseline characteristics, whenever compared, were comparable between both groups. There was nonsignificant difference between TI and TT techniques in the distance from aperture center to footprint center and both techniques were unable to accurately recreate the anatomic footprint position. TI technique significantly placed aperture at more posterior position than TT technique. TI technique significantly lowered position of placed aperture perpendicular to Blumensaat’s line (BL) than TT technique, and modifications to TT technique had significant effect on this intervention effect. Regarding sagittal plane aperture placement along both AP anatomical axis and BL, there was nonsignificant difference between both techniques.

Conclusion

Modifications to TT technique could overcome limitations in aperture placement perpendicular to BL. The more anterior placement of femoral aperture by TT technique might be considered, to some extent, a proper position according to recent concept of functional anatomical ACL reconstruction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03040-5.

Posteriorly positioned femoral grafts decrease long-term failure in anterior cruciate ligament reconstruction, femoral and tibial graft positions did not affect long-term reported outcome

PURPOSE

To investigate the effect that femoral and tibial tunnel positions have on long-term reported and clinical outcome and to identify a safe zone based on favourable outcome.

METHODS

Seventy-eight patients from a previous randomised controlled trial were included and were followed with a mean follow-up of 11.4 years. All patients had primary trans-tibial anterior cruciate ligament reconstruction performed. The femoral and tibial tunnel positions were visualised and translated in percentages with three-dimensional computed tomography post-operatively. There were 3 separate outcome variables: patient-reported outcome measured with the IKDC Subjective Knee Form, overall failure, and radiographic osteoarthritis. The correlation between tunnel aperture positions and outcome was determined with multivariate regression. The area with best outcome was defined as the safe zone and was determined with Youden's index in conjunction with receiver operating characteristics.

RESULTS

No significant relationship was found between tunnel aperture positions and IKDC Subjective Knee Form at 10-year follow-up. The posterior-to-anterior femoral tunnel aperture position parallel to Blumensaat line showed a significant relationship (p = 0.03) to overall failure at 10-year follow-up. The mean posterior-to-anterior tunnel position of the group that did not fail was 37.7% compared to 44.1% in the overall failure group. Femoral tunnel apertures placed further anteriorly had more overall failures at long-term. The cut-off point lies at 35.0% from posterior-to-anterior parallel to Blumensaat. Of the 16 overall failures, 15 (93.8%) were placed further anteriorly than the cut-off point. No significant relationship was found between tunnel aperture positions and radiographic osteoarthritis.

CONCLUSION

Femoral and tibial tunnel positions were not associated with long-term patient-reported outcome and radiographic osteoarthritis. Long-term overall failure was more frequently seen in patients with a more anteriorly placed femoral tunnel. This study identified a safe zone located at the most posterior 35% of the femoral condyle parallel to Blumensaat. This knowledge offers guidance to surgeons to operate more precisely and accurately and reconstruct a long-lasting graft.

LEVEL OF EVIDENCE

Level III.

Higher Incidence of Radiographic Posttraumatic Osteoarthritis With Transtibial Femoral Tunnel Positioning Compared With Anteromedial Femoral Tunnel Positioning During Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

Anteromedial (AM) femoral tunnel positioning in anterior cruciate ligament reconstruction (ACLR) has been reported by some authors to yield superior clinical and functional outcomes compared with the transtibial (TT) approach; however, differences in the subsequent rates of posttraumatic osteoarthritis (PTOA) are not clear.

PURPOSE

To perform a systematic review and meta-analysis of the literature to evaluate the influence of femoral tunnel positioning during primary ACLR on the development of radiographic PTOA.

STUDY DESIGN

Systematic review and Meta-analysis.

METHODS

The Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed (1980-2019), and MEDLINE (1980-2019) were queried for all studies describing the development of PTOA after TT or AM ACLR. Data pertaining to patient demographics, ACLR technique, and radiographic PTOA were extracted. A meta-analysis utilizing the DerSimonian-Laird method for random effects was used to compare the weighted proportion of PTOA after ACLR between the TT and AM approaches.

RESULTS

There were 16 studies identified for inclusion with a total of 1546 patients. The mean follow-up across all studies was 10.9 years (range, 5.4-17.8 years). The mean follow-up in the AM and TT groups was 10.8 years (range, 5.4-17 years) and 11.4 years (range, 6-17.8 years), respectively. A total of 783 (50.6%) patients underwent TT ACLR. Of these patients, 401 (weighted mean, 49.3%) developed radiographic PTOA. A total of 763 (49.4%) patients underwent AM ACLR. Of these patients, 166 (mean, 21.8%) went on to develop radiographic PTOA. The meta-analysis demonstrated a significantly greater rate of PTOA after ACLR using a TT technique compared with an AM technique overall (49.3% vs 25.4%, respectively; P < .001) and when studies were stratified by 5- to 10-year (53.7% vs 14.2%, respectively; P < .001) and greater than 10-year (45.6% vs 31.2%, respectively; P < .0001) follow-up.

CONCLUSION

TT ACLR was associated with higher overall rates of radiographic PTOA compared with the AM ACLR approach. The rates of radiographic PTOA after ACLR with a TT approach were also significantly higher than using an AM approach when stratified by length of follow-up (5- to 10-year and >10-year follow-up).

Systematic Review of Surgical Technique and Tunnel Target Points and Placement in Anatomical Single-Bundle ACL Reconstruction

The purpose of this systematic review was to reveal the trend in surgical technique and tunnel targets points and placement in anatomical single-bundle anterior cruciate ligament (ACL) reconstruction. Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, data collection was performed. PubMed, EMBASE, and Cochran Review were searched using the terms "anterior cruciate ligament reconstruction," "anatomic or anatomical," and "single bundle." Studies were included when they reported clinical results, surgical technique, and/or tunnel placement evaluation. Laboratory studies, technical reports, case reports, and reviews were excluded from this study. From these full article reviews, graft selection, method of creating the femoral tunnel, and femoral and tibial tunnel target points and placement were evaluated. In the 79 studies included for data evaluation, the selected grafts were: bone patella tendon bone autograft (12%), and hamstring autograft (83%). The reported methods of creating the femoral tunnel were: transportal technique (54%), outside-in technique (15%), and transtibial technique (19%). In the 60 studies reporting tunnel target points, the target point was the center of the femoral footprint (60%), and the center of the anteromedial bundle footprint (22%). In the 23 studies evaluating tunnel placement, the femoral tunnel was placed in a shallow-deep direction (32.3%) and in a high-low direction (30.2%), and the tibial tunnel was placed from the anterior margin of the tibia (38.1%). The results of this systematic review revealed a trend in anatomical single-bundle ACL reconstruction favoring a hamstring tendon with a transportal technique, and a tunnel target point mainly at the center of the ACL footprint. The level of evidence stated is Systematic review of level-III studies.

Current and future of anterior cruciate ligament reconstruction techniques

In recent years, anterior cruciate ligament (ACL) reconstruction has generally yielded favorable outcomes. However, ACL reconstruction has not provided satisfactory results in terms of the rate of returning to sports and prevention of osteoarthritis (OA) progression. In this paper, we outline current techniques for ACL reconstruction such as graft materials, double-bundle or single-bundle reconstruction, femoral tunnel drilling, all-inside technique, graft fixation, preservation of remnant, anterolateral ligament reconstruction, ACL repair, revision surgery, treatment for ACL injury with OA and problems, and discuss expected future trends. To enable many more orthopedic surgeons to achieve excellent ACL reconstruction outcomes with less invasive surgery, further studies aimed at improving surgical techniques are warranted. Further development of biological augmentation and robotic surgery technologies for ACL reconstruction is also required.

All-Inside Anterior Cruciate Ligament Reconstruction Using Quadrupled Semitendinosus: Comparable 2-Year Outcomes in Male and Female Patients

PURPOSE

To determine 2-year functional outcomes using an all-inside quadrupled semitendinosus anterior cruciate ligament (ACL) reconstruction technique in male and female patients.

METHODS

A total of 100 patients who underwent quadrupled semitendinosus all-inside hamstring ACL reconstruction by a single surgeon were enrolled. Patient-reported outcome scores collected preoperatively and postoperatively included visual analog scale, Veterans Rand 12-Item Health Survey (VR-12; Physical and Mental), Marx Activity Scale, Knee Injury and Osteoarthritis Outcome Scores (KOOS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

RESULTS

A total of 100 ACL reconstructions comprising 62 female, and 38 male patients were included in this study. Mean graft diameter was 9.4 mm in female and 9.8 mm in male patients (range, 9-11). Outcome scores demonstrated improvement from preoperative to 2-year postoperative respectively: visual analog scale pain 3.18, 1.07, VR-12 physical 36.35, 52.64, VR-12 mental 53.96, 54.65, KOOS pain 59.17, 89.03, KOOS symptoms 52.64, 80.79, KOOS Activities of Daily Living 69.38, 95.4, KOOS Sport 28.97, 81.25, KOOS Quality of Life 27.54, 71.56, WOMAC Pain 71.56, 92.65, WOMAC Stiffness 60.55, 84.13, and WOMAC Function 69.38, 95.4. Marx activity score decreased from baseline (10.98) to 2 years' postoperatively (8.75). At 2 years, patient expectations were met or exceeded with regards to pain (94%), motion and strength (91%), normal function of daily living (95%), and return to sport (79%).

CONCLUSIONS

Anatomic all-inside quadrupled semitendinosus ACL reconstruction improves functional outcomes similarly to previous studies between baseline and clinical follow-up at 1-year and 2-years postoperatively and is comparable in both male and female patients.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

The Graft Insertion Length in the Femoral Tunnel During Anterior Cruciate Ligament Reconstruction With Suspensory Fixation and Tibialis Anterior Allograft Does Not Affect Surgical Outcomes but Is Negatively Correlated With Tunnel Widening

PURPOSE

To investigate the surgical outcomes of anterior cruciate ligament (ACL) reconstruction using a low-dose irradiated tibialis anterior allograft with a fixed-loop cortical suspension device for the femur based on the graft insertion length (GIL) in the femoral tunnel.

METHODS

Between January 2010 and January 2018, the medical records of consecutive patients who underwent arthroscopic ACL reconstruction with a tibialis anterior allograft fixed with the EndoButton CL for the femur and who had at least 2 years of follow-up were retrospectively evaluated. Patients were classified into 3 groups based on the GIL in the femoral tunnel (group 1, GIL < 15 mm; group 2, GIL of 15-20 mm; and group 3, GIL > 20 mm), and their functional scores, knee laxity, and radiographic parameters were evaluated.

RESULTS

A total of 91 patients were analyzed. There were no statistically significant differences in the functional scores and knee laxity between the 3 groups at 2 years postoperatively. However, significant differences were observed in tunnel widening at 1 year postoperatively in the femur (P = .045 for absolute value and P = .004 for relative value) and the tibia (P = .014 for absolute value and P = .012 for relative value), revealing that both the femoral and tibial tunnels widened as the GIL decreased. Additional linear regression analyses were performed to identify whether the GIL independently affects tunnel widening. Consequently, the femoral tunnel depth, tunnel diameter, and GIL were found to independently influence femoral tunnel widening (P = .008, P = .019, and P < .001, respectively), whereas the tunnel diameter and GIL affected tibial tunnel widening (P < .001 and P = .004, respectively).

CONCLUSIONS

The GIL in the femoral tunnel during ACL reconstruction using a tibialis anterior allograft with a fixed-loop cortical suspension device for the femur has no significant association with the postoperative functional outcomes and knee laxity, but it has a negative correlation with tunnel widening in the femur and the tibia.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Clinical and Radiological Outcomes of Anteromedial Portal Versus Transtibial Technique in ACL Reconstruction: A Systematic Review

Background:

The drilling technique used to make a femoral tunnel is critically important for determining outcomes after anterior cruciate ligament (ACL) reconstruction. The 2 most common methods are the transtibial (TT) and anteromedial (AM) techniques.

Purpose:

To determine whether graft orientation and placement affect clinical outcomes by comparing clinical and radiological outcomes after single-bundle ACL reconstruction with the AM versus TT technique.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

Articles in PubMed, EMBASE, the Cochrane Library, ISI Web of Science, Scopus, and MEDLINE were searched from inception until April 25, 2020, using the following Boolean operators: transtibial OR trans-tibial AND (anteromedial OR trans-portal OR independent OR three portal OR accessory portal) AND anterior cruciate ligament.

Results:

Of 1270 studies retrieved, 39 studies involving 11,207 patients were included. Of these studies, 14 were clinical, 13 were radiological, and 12 were mixed. Results suggested that compared with the TT technique, the AM technique led to significantly improved anteroposterior and rotational knee stability, International Knee Documentation Committee (IKDC) scores, and recovery time from surgery. A higher proportion of negative Lachman (P = .0005) and pivot-shift test (P = .0001) results, lower KT-1000 arthrometer maximum manual displacement (P = .00001), higher Lysholm score (P = .001), a higher incidence of IKDC grade A/B (P = .05), and better visual analog scale score for satisfaction (P = .00001) were observed with the AM technique compared with the TT technique. The AM drilling technique demonstrated a significantly shorter tunnel length (P = .00001). Significant differences were seen between the femoral and tibial graft angles in both techniques. Low overall complication and revision rates were observed for ACL reconstruction with the AM drilling technique, similar to the TT drilling technique.

Conclusion:

In single-bundle ACL reconstruction, the AM drilling technique was superior to the TT drilling technique based on physical examination, scoring systems, and radiographic results. The AM portal technique provided a more reproducible anatomic graft placement compared with the TT technique.

Comparison of Clinical Outcomes between Anteromedial and Transtibial Techniques of Single-Bundle Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

This study compared clinical outcomes obtained after single-bundle anterior cruciate ligament (ACL) reconstruction using the anteromedial (AM) and transtibial (TT) techniques, which comprise the conventional transtibial (cTT) and modified transtibial (mTT) techniques. This study included clinical randomized controlled trials and prospective and retrospective controlled trials with AM and TT techniques from the PubMed and Embase databases and the Cochrane Library. All databases were searched from January 2010 to July 2020. Two independent evaluators verified the quality of the included studies using the Cochrane Collaboration's risk of bias tool and the Newcastle-Ottawa Scale (NOS). Outcome measures analysed included the Lachman test, pivot-shift test, side-to-side difference (SSD), Lysholm score, Tegner activity scale, International Knee Documentation Committee (IKDC) grade and score. Ten randomized controlled trials (RCTs) and 16 prospective and retrospective controlled trials were included with a total of 2202 patients. There were 1180 patients and 1022 patients in the AM and TT groups, respectively. Compared to the cTT group, superior postoperative results were observed in the AM group based on the negative rate of the Lachman test and the pivot-shift test, IKDC grade and score, Lysholm score, Tegner activity scale and SSD (p < 0.05). However, there was no significant difference between the AM and mTT groups (p > 0.05). Compared to the conventional TT technique, the AM technique exhibited superior clinical outcomes. Nevertheless, the modified TT and AM techniques had comparable results. With neither of the techniques (mTT or AM) producing significantly superior outcomes, surgeons can choose either of them depending on their preferences.

Anterior cruciate ligament reconstruction femoral tunnel drilling preference among orthopaedic surgeons

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) technique for femoral tunnel drilling varies substantially, each with advantages and disadvantages. The purpose of this study was to define ACLR femoral tunnel technique predilection among surgeons and to explore factors associated with their preference.

METHODS

An 11-question survey regarding ACLR femoral tunnel technique was completed by 560 AANA/AOSSM members. Surgeon and practice demographics and residency and fellowship experiences were evaluated with bivariate and multivariable models for association with surgeon preference.

RESULTS

In current practice, 55% of surgeons prefer anteromedial (AM) portal drilling, 32% retrograde, and 14% transtibial (TT). Sports Medicine fellowship experience was the strongest predictor of current practice (p < 0.001), followed by residency technique (p = 0.014). A significant increase in TT drilling was noted for those practicing >15 years TT (29% vs 3%, p < 0.001), with an inverse relationship for retrograde drilling (38% vs 21%, p < 0.001). Number of ACLRs/year and percent Sports specific practice were significant predictors for AM drilling (p < 0.001). Though less than AM and retrograde, TT was more common for those in private practice (17% vs 8%, p < 0.001), and more prevalent in the Midwest/Southeast (19% vs 10%, p = 0.003). Non-significant predictors included highest level of athlete for whom an ACLR had been performed, level of athlete serving as team physician, and Certificate of Added Qualifications status.

CONCLUSION

Surgeon training, practice setting, and years in practice significantly predict preference for femoral tunnel drilling technique. Surgeon comfort and confidence in attaining an anatomic reconstruction should drive choice of technique.

Systematic Review of Silk Scaffolds in Musculoskeletal Tissue Engineering Applications in the Recent Decade

During the past decade, various novel tissue engineering (TE) strategies have been developed to maintain, repair, and restore the biomechanical functions of the musculoskeletal system. Silk fibroins are natural polymers with numerous advantageous properties such as good biocompatibility, high mechanical strength, and low degradation rate and are increasingly being recognized as a scaffolding material of choice in musculoskeletal TE applications. This current systematic review examines and summarizes the latest research on silk scaffolds in musculoskeletal TE applications within the past decade. Scientific databases searched include PubMed, Web of Science, Medline, Cochrane library, and Embase. The following keywords and search terms were used: musculoskeletal, tendon, ligament, intervertebral disc, muscle, cartilage, bone, silk, and tissue engineering. Our Review was limited to articles on musculoskeletal TE, which were published in English from 2010 to September 2019. The eligibility of the articles was assessed by two reviewers according to prespecified inclusion and exclusion criteria, after which an independent reviewer performed data extraction and a second independent reviewer validated the data obtained. A total of 1120 articles were reviewed from the databases. According to inclusion and exclusion criteria, 480 articles were considered as relevant for the purpose of this systematic review. Tissue engineering is an effective modality for repairing or replacing injured or damaged tissues and organs with artificial materials. This Review is intended to reveal the research status of silk-based scaffolds in the musculoskeletal system within the recent decade. In addition, a comprehensive translational research route for silk biomaterial from bench to bedside is described in this Review.

Anterior Cruciate Ligament Femoral Socket Preparation Using a Cannulated, Calibrated Drill With Adjustable Stop and Slotted Cannula

Anteromedial portal-guided femoral tunnel preparation during anterior cruciate ligament reconstruction can be difficult owing to poor visualization. This may cause iatrogenic damage to the medial femoral condyle cartilage and the posterior cruciate ligament fibers or overdrilling through the lateral femoral cortex, creating difficulties in the use of femoral suspensory devices during anterior cruciate ligament reconstruction. We describe an accurate and safe technique for femoral graft socket preparation using a cannulated, calibrated drill with an adjustable stop and slotted cannula. This easy and reproducible technique uses simple additional instruments and effectively addresses concerns related to femoral graft socket preparation, without requiring additional surgical time.

Remnant preservation provides good clinical outcomes after anterior cruciate ligament reconstruction

PURPOSE

To evaluate the association of remnant preservation (RP) and non-RP (NRP) with patient-reported outcome measures and subsequent graft rupture at a minimum 2-year follow-up after anterior cruciate ligament (ACL) reconstruction.

METHODS

Patients in this retrospective study underwent primary isolated ACL reconstruction by the RP or NRP technique with a four- to five-strand hamstring tendon graft. Multivariate linear or logistic regression and Cox regression analyses were performed to compare the physical and psychological outcomes by the International Knee Documentation Committee subjective knee form (IKDC-SKF) and the Japanese Anterior Cruciate Ligament questionnaire 25 (JACL-25), respectively; satisfaction rate; and prognosticators of graft rupture.

RESULTS

In total, 120 patients (mean age, 30.6 ± 12.7 years; 54 RP, 66 NRP) with a mean follow-up of 3.2 ± 1.6 years were enrolled in this study. At the latest postoperative follow-up, the RP group showed a mean IKDC-SKF score of 92.3 ± 8.5 and mean JACL-25 score of 13.2 ± 11.2, while these scores in the NRP group were 86.4 ± 12.2 and 24.4 ± 19.5, respectively (P = 0.016 and 0.007, respectively). No significant differences were found in the return-to-sports rate (RP vs. NRP, 79.5% vs. 67.5%) or satisfaction rate (RP vs. NRP, 89.2% vs. 74.4%) (n.s.); however, a significant difference was found in the rate of return to the preinjury sports level (RP vs. NRP, 64.1% vs. 37.5%; P = 0.014). The graft rupture rate was significantly higher in the NRP than RP group (9/66 vs. 1/54; hazard ratio 9.29; 95% confidence interval 1.04-82.81). Younger age (≤ 18 years) was the other important risk factor for graft rupture (hazard ratio 8.67; 95% confidence interval 2.02-37.13).

CONCLUSION

Patients who underwent ACL reconstruction with the RP technique obtained somewhat better physical and psychological results than those who underwent ACL reconstruction with the NRP technique. With respect to clinical relevance, patients treated with the RP technique may obtain better outcomes in terms of graft rupture and return to the preinjury sports level than those treated with the NRP technique, but with no differences in overall return to sports or satisfaction.

LEVEL OF EVIDENCE

IV.

The Relationship Between Lateral Femoral Anatomic Structures and the Femoral Tunnel Outlet in Anterior Cruciate Ligament Reconstruction Using the Transportal Technique: A 3-Dimensional Simulation Analysis

BACKGROUND

The relationship between the lateral femoral anatomic structures and femoral tunnel outlet according to changes in knee flexion and transverse drill angle during femoral tunnel creation in anterior cruciate ligament (ACL) reconstruction remains unclear.

PURPOSE

To investigate the relationships between the lateral femoral anatomic structures and femoral tunnel outlet according to various knee flexion and transverse drill angles and to determine appropriate angles at which to minimize possible damage to the lateral femoral anatomic structures.

STUDY DESIGN

Controlled laboratory study.

METHODS

Simulation of ACL reconstruction was conducted using a 3-dimensional reconstructed knee model from the knees of 30 patients. Femoral tunnels were created using combinations of 4 knee flexion and 3 transverse drill angles. Distances between the femoral tunnel outlet and lateral femoral anatomic structures (minimum safe distance, 12 mm), tunnel length, and tunnel wall breakage were assessed.

RESULTS

Knee flexion and transverse drill angles independently affected distances between the femoral tunnel outlet and lateral femoral anatomic structures. As knee flexion angle increased, the distance to the lateral collateral ligament, lateral epicondyle, and popliteal tendon decreased, whereas the distance to the lateral head of the gastrocnemius increased (P < .001). As the transverse drill angle decreased, distances to all lateral femoral anatomic structures increased (P < .001). Considering safe distance, 120°, 130°, or 140° of knee flexion and maximum transverse drill angle (MTA) could damage the lateral collateral ligament; 130° or 140° of knee flexion and MTA could damage the lateral epicondyle; and 110° or 120° of knee flexion and MTA could damage the lateral head of the gastrocnemius. Tunnel wall breakage occurred under the conditions of MTA - 10° or MTA - 20° with 110° of knee flexion and MTA - 20° with 120° of knee flexion.

CONCLUSION

Approximately 120° of knee flexion with MTA - 10° and 130° or 140° of knee flexion with MTA - 20° or MTA - 10° could be recommended to prevent damage to the lateral femoral anatomic structures, secure adequate tunnel length, and avoid tunnel wall breakage.

CLINICAL RELEVANCE

Knee flexion angle and transverse drill angle may affect femoral tunnel creation, but thorough studies are lacking. Our findings may help surgeons obtain a stable femoral tunnel while preventing damage to the lateral femoral anatomic structures.

Three-Dimensional Magnetic Resonance Imaging for Guiding Tibial and Femoral Tunnel Position in Anterior Cruciate Ligament Reconstruction: A Cadaveric Study

Background:

Femoral and tibial tunnel malposition for anterior cruciate ligament (ACL) reconstruction (ACLR) is correlated with higher failure rate. Regardless of the surgical technique used to create ACL tunnels, significant mismatches between the native and reconstructed footprints exist.

Purpose:

To compare the position of tunnels created by a standard technique with the ones created based on preoperative 3-dimensional magnetic resonance imaging (3D MRI) measurements of the ACL anatomic footprint.

Study Design:

Controlled laboratory study.

Methods:

Using 3D MRI, the native ACL footprints were identified. Tunnels were created on 16 knees (8 cadavers) arthroscopically. On one knee of a matched pair, the tunnels were created based on 3D MRI measurements that were provided to the surgeon (roadmapped technique), while on the contralateral knee, the tunnels were created based on a standard anatomic ACLR technique. The technique was randomly assigned per set of knees. Postoperatively, the positions of the tunnels were measured using 3D MRI.

Results:

On the tibial side, the median distance between the center of the native and reconstructed ACL footprints in relation to the root of the anterior horn of the lateral meniscus medially was 1.7 ± 2.2 mm and 1.9 ± 2.8 mm for the standard and roadmapped techniques, respectively (P = .442), while the median anteroposterior distance was 3.4 ± 2.4 mm and 2.5 ± 2.5 mm for the standard and roadmapped techniques, respectively (P = .161). On the femoral side, the median distance in relation to the apex of the deep cartilage (ADC) distally was 0.9 ± 2.8 mm and 1.3 ± 2.1 mm for the standard and roadmapped techniques, respectively (P = .195), while the median distance anteriorly from the ADC was 1.2 ± 1.3 mm and 4.6 ± 4.5 mm for the standard and roadmapped techniques, respectively (P = .007).

Conclusion:

Providing precise radiological measurements of the ACL footprints does not improve the surgeon’s ability to position the tunnels. Future studies should continue to attempt to provide tools to improve the tunnel position in ACLR.

Clinical Relevance:

This cadaveric study indicates that despite the use of 3D MRI in understanding the ACL anatomy, re-creating the native ACL footprints remains a challenge.

Comparison of femoral tunnel length and obliquity of anatomic versus nonanatomic anterior cruciate ligament reconstruction: A meta-analysis

Purpose

Theoretical considerations suggest that femoral tunnel length might cause graft mismatch, and femoral tunnel obliquity could be related to the longevity of graft in anterior cruciate ligament (ACL) reconstruction. However, controversy still exists regarding these issues in the context of the comparison of anatomic and nonanatomic ACL reconstructions. The purpose of this meta-analysis was to compare the length and obliquity of the femoral tunnel created by drilling through either anatomic or nonanatomic ACL reconstructions.

Materials and method

In this meta-analysis, we reviewed studies that compared femoral tunnel length and femoral tunnel obliquity in the coronal plane with the use of anatomic or nonanatomic ACL reconstruction. The major databases were reviewed for appropriate studies from the earliest available date of indexing through December 31, 2018. No restrictions were placed on the language of publication.

Results

Twenty-seven studies met the criteria for inclusion in this meta-analysis. The femur tunnel length of anatomic ACL reconstruction was significantly shorter compared with that of nonanatomic ACL reconstruction by 8.66 mm (95% CI: 7.10–10.22 mm; P<0.001), while the femur tunnel obliquity in the coronal plane of anatomic ACL reconstruction was significantly more oblique versus that of nonanatomic ACL reconstruction by 15.29° (95% CI: 8.07°–22.52°; P<0.001). Similar results in terms of femoral tunnel length were found for the subgroup with cadaveric (7.15 mm; 95% CI: 2.69–11.61 mm; P = 0.002) and noncadaveric (8.96 mm; 95% CI: 7.24–10.69 mm; P<0.001) studies, whereas different results in terms of femoral tunnel obliquity were noted for the subgroup with cadaveric (10.62°; 95% CI: −6.12° to 27.37°; P = 0.21) and noncadaveric (15.86°; 95% CI: 8.11°–23.60°; P<0.001) studies.

Conclusion

Anatomic ACL reconstruction resulted in the femoral tunnel length and femoral tunnel obliquity in the coronal plane being shorter and more oblique, respectively, as compared with nonanatomic ACL reconstruction.

Level of evidence

Therapeutic study, Level III.

The Association Between Anterior Cruciate Ligament Length and Femoral Epicondylar Width Measured on Preoperative Magnetic Resonance Imaging or Radiograph

PURPOSE

To determine whether femoral epicondylar width (FECW) obtained from either magnetic resonance imaging (MRI) or plain radiographs could be used to predict anterior cruciate ligament (ACL) length. A secondary purpose was to develop a formula to use maximum FECW on either MRI or plain radiographs to estimate ACL length preoperatively.

METHODS

The MRIs and radiographs of 40 patients (mean age 41.0 years), with no apparent knee pathology, surgery, or trauma were included. The ACL length was measured on MRI followed by FECW on both MRI and radiograph of the same patient. This allowed the development of equations able to predict ACL length according to the FECW measured on either an MRI or radiograph.

RESULTS

The mean ACL length was 40.6 ± 3.6 mm. FECW measured on both MRIs and radiographs was sufficient to predict ACL length. Pearson's correlations revealed a high positive relationship between ACL length and FECW on MRI (r = 0.89, P < .0001) and ACL length and FECW on radiograph (r = 0.83, P < .0001). The coefficient of determination (R2) was calculated to be MRI: R2 = 0.78 and radiograph: R2 = 0.68 and confirmed that FECW measured on both MRI and radiograph were sufficient to predict ACL length. Based on these models, ACL length can be predicted by FECW using the following formulas: MRI: ACL length = 0.47 (FECW) + 1.93 and radiograph: ACL length = 0.31 (FECW) + 11.33.

CONCLUSIONS

This study demonstrated that FECW measured on either MRI or anteroposterior radiograph could reliably estimate ACL length on a sagittal MRI. There was a high positive relationship between ACL length and FECW on both MRI and radiographs, although MRIs do predict ACL length more reliably.

CLINICAL RELEVANCE

Preoperative ACL length assessment, using FECW on MRI or radiograph, is useful in graft selection and in preventing inadequate graft harvesting for ACL reconstruction, especially if an individualized anatomical approach is pursued.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of anterior cruciate ligament injury - Secondary publication

BACKGROUND

This clinical guideline presents recommendations for the management of patients with anterior cruciate ligament (ACL) injury, endorsed by the Japanese Orthopaedic Association (JOA) and Japanese Orthopaedic Society of Knee, Arthroscopy and Sports Medicine (JOSKAS).

METHODS

The JOA ACL guideline committee revised the previous guideline based on "Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014", which proposed a desirable method for preparing clinical guidelines in Japan. Furthermore, the importance of "the balance of benefit and harm" was also emphasized. This guideline consists of 21 clinical questions (CQ) and 23 background questions (BQ). For each CQ, outcomes from the literature were collected and evaluated systematically according to the adopted study design.

RESULTS

We evaluated the objectives and results of each study in order to make a decision on the level of evidence so as to integrate the results with our recommendations for each CQ. For BQ, the guideline committee proposed recommendations based on the literature.

CONCLUSIONS

This guideline is intended to be used by physicians, orthopedic surgeons, physical therapists, and athletic trainers managing ACL injuries. We hope that this guideline is useful for appropriate decision-making and improved management of ACL injuries.

Does Knee Flexion Influence the Relationship between the Femoral Tunnel and the Lateral Anatomic Structures During ACL Reconstruction?

BACKGROUND

In ACL reconstruction, the relationship of the femoral tunnel outlet to the anatomy of the lateral knee is clinically important, but whether that relationship is influenced by knee flexion using a transportal technique is unclear.

QUESTIONS/PURPOSES

The purposes of this study were to (1) to describe the relationship between the outlet of the femoral tunnel and the lateral anatomic structures of the femur, including the lateral epicondyle, lateral collateral ligament, popliteus tendon, and lateral head of the gastrocnemius, as a function of knee flexion angle when the tunnel was created; and (2) to determine the knee flexion range of angles that best limits the risk of damage to these structures as the femoral tunnel is created during anatomic single-bundle ACL reconstruction using the transportal technique.

METHODS

Between January 2017 and June 2018, 113 patients underwent ACL reconstruction, of which 62 (55%) who had a primary single-bundle ACL reconstruction with transportal technique using autogenous quadruple hamstring graft were included. Patients who were treated with grafts other than autogenous quadruple hamstring tendon, and had concomitant ligamentous injury, revisional ACL reconstruction, previous operative history of the affected knee, osseous deformity and osteoarthritis were excluded. Included patients were divided into three groups according to their knee flexion angles as the femoral tunnel was created. The femoral tunnel was created with rigid straight reamer with the knee flexed as much as possible in figure-of-four position and the flexion angle was measured with a sterile 12-inch goniometer intraoperatively for all patients. Fourteen patients (23%) had the femoral tunnel created with the knee in < 120° of flexion, 23 (37%) had the tunnel created in 120° to 129° of flexion, and 25 (40%) had the tunnel created in ≥ 130° of flexion. The femoral tunnel's outlet and the lateral anatomic structures of the femur, including the femoral origins of the lateral epicondyle, lateral collateral ligament, popliteus tendon, and lateral head of the gastrocnemius, were identified on a three-dimensional model that was reconstructed using CT images taken on postoperative day 1. The shortest distances from the femoral tunnel's outlet to these lateral anatomic structures were measured by two observers and interobserver reliability was high (intraclass correlation coefficient > 0.75). The distances were compared among the groups, and a correlation analysis of the measured distances regarding the knee flexion angle during creation of the femoral tunnel was performed. The safe distance was set as 12 mm between the centers of the femoral tunnel's outlet and the lateral structures considering the footprint of the lateral structures, diameter of the femoral tunnel, and femoral tunnel widening. Any anatomic structures that were closer to the femoral tunnel than the safe distance were noted, and the cutoff point of knee flexion for injury to the lateral anatomic structures was determined with a receiver operating characteristic curve.

RESULTS

As knee flexion angle increased, the distance from the femoral tunnel to the lateral head of the gastrocnemius increased (r = 0.657, p < 0.001), and the distance to the lateral epicondyle decreased (r = -0.627, p < 0.001), as did the distance of the tunnel to the lateral collateral ligament (r = -0.443, p < 0.001) and the popliteus tendon (r = -0.653, p < 0.001). The cutoff point of the knee flexion angle associated with structural injury was 131° (sensitivity, 70%; specificity, 73%) for the lateral collateral ligament and 121° (sensitivity, 86%; specificity, 67%) for the lateral head of the gastrocnemius.

CONCLUSIONS

As knee flexion increased, the femoral tunnel's outlet tended to move more anteriorly and distally. Consequently, the safe distance to the lateral head of the gastrocnemius increased and the distances to the lateral epicondyle, lateral collateral ligament, and popliteus tendon decreased with increased knee flexion. To avoid possible damage to the lateral anatomic structures and obtain stable fixation in ACL reconstruction using the transportal technique, we recommend creating a femoral tunnel within 121° and 131° of knee flexion.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Tunnel placement in ACL reconstruction surgery: smaller inter-tunnel angles and higher peak forces at the femoral tunnel using anteromedial portal femoral drilling-a 3D and finite element analysis

PURPOSE

Recent studies have emphasized the importance of anatomical ACL reconstruction to restore normal knee kinematics and stability. Aim of this study is to evaluate and compare the ability of the anteromedial (AM) and transtibial (TT) techniques for ACL reconstruction to achieve anatomical placement of the femoral and tibial tunnel within the native ACL footprint and to determine forces within the graft during functional motion. As the AM technique is nowadays the technique of choice, the hypothesis is that there are significant differences in tunnel features, reaction forces and/or moments within the graft when compared to the TT technique.

METHODS

Twenty ACL-deficient patients were allocated to reconstruction surgery with one of both techniques. Postoperatively, all patients underwent a computed tomography scan (CT) allowing 3D reconstruction to analyze tunnel geometry and tunnel placement within the native ACL footprint. A patient-specific finite element analysis (FEA) was conducted to determine reaction forces and moments within the graft during antero-posterior translation and pivot-shift motion.

RESULTS

With significantly shorter femoral tunnels (p < 0.001) and a smaller inter-tunnel angle (p < 0.001), the AM technique places tunnels with less variance, close to the anatomical centre of the ACL footprints when compared to the TT technique. Using the latter, tibial tunnels were more medialised (p = 0.007) with a higher position of the femoral tunnels (p = 0.02). FEA showed the occurrence of higher, but non-significant, reaction forces in the graft, especially on the femoral side and lower, however, statistically not significant, reaction moments using the AM technique.

CONCLUSION

This study indicates important, technique-dependent differences in tunnel features with changes in reaction forces and moments within the graft.

LEVEL OF EVIDENCE

II.

Outcomes of revision anterior cruciate ligament reconstruction secondary to reamer-irrigator-aspirator harvested bone grafting

INTRODUCTION

Patients with widened or misplaced tunnels may require bone grafting prior to revision anterior cruciate ligament (ACL) reconstruction. Utilising reamer-irrigator-aspirator (RIA) harvested bone from the femur showed promising filling rates. Nevertheless, the procedure has neither been validated in a larger population nor been assessed with regards to radiological and clinical outcome of the subsequently conducted revision ACL reconstruction. Therefore, the aim of this study was to evaluate tunnel filling rates, positioning of the revision tunnels and outcome parameters of such two-staged revision ACL reconstructions.

MATERIAL AND METHODS

A total of 15 consecutive patients were prospectively enrolled in this case series. CT scans were analysed before and after autologous RIA harvested bone grafting. Tunnel volumes and filling rates were calculated based on manual segmentation of axial CT scans. Revision ACL reconstruction was carried out after a mean interval of 6.2 months (±3.7) and positioning of the revision tunnels was assessed by plane radiographs. The mean follow-up was 19.8 months (±8.4) for objective evaluation and 37.1 months (±15.4) for patient reported outcomes. The clinical outcome was assessed by the quantification of the anterior tibial translation, the IKDC objective score, the Tegner activity scale and the Lysholm score.

RESULTS

Initial CT scans revealed mean tunnel volumes of 3.8cm³ (±2.7) femoral and 6.1cm³ (±2.4) tibial. Filling rates of 76.1% (±12.4) femoral and 87.4% (±5.9) tibial were achieved. Postoperative radiographs revealed significantly improved tunnel positioning with anatomical placement in all but one case at the femur and in all cases at the tibia. At follow up, patients showed significantly improved anterior tibial translations with residual side-to-side differences of 1.7 mm (±0.8) and significantly improved IKDC objective scores. Furthermore, significantly higher values were achieved on the Tegner activity scale (5.3 ± 1.4 vs. 2.8 ± 0.5) and the Lysholm score (85.4 ± 7.9 vs. 62.5 ± 10.5) compared to the preoperative status.

CONCLUSION

Autologous RIA harvested bone grafting ensures sufficient bone stock consolidation allowing for anatomical tunnel placement of the subsequently conducted revision ACL reconstruction. The two-staged procedure reliably restores stability and provides satisfying subjective and objective outcomes. Thus, RIA harvested bone grafting is an eligible alternative to autologous iliac crest or allogenic bone grafting.

Comparison of 2 femoral tunnel drilling techniques in anterior cruciate ligament reconstruction. A prospective randomized comparative study

BACKGROUND

To evaluate the length and position of femoral tunnel,and exam whether knee stability and clinical functional outcomes are superior in AMP method.

METHODS

From August 2014 to February 2015, we prospectively recruited 104 patients undergoing anterior cruciate ligament reconstruction. They were randomized to anteromedial portal or transtibial method. All patients underwent Lysholm score, International Knee Documentation Committee score,Tegner score at pre-operative and last follow-up point as subjective assessment of clinical function. The Lachman test, the Pivot-shift test and KT-1000 were performed at the last follow-up as a evaluation of knee joint stability. We measured the length of femoral tunnel intraoperatively and at 1 week post-operatively, CT-based three-dimensional reconstruction was used to assess femoral tunnel location.

RESULTS

The average follow-up time of anteromedial portal group was 25.7 ± 6.8 months (range:12-36.5 months), and the average follow-up time of the transtibial group was 24.9 ± 6.0 months (range:12-37 months). There was no significant difference between the groups pre-operative Lysholm score, IKDC score and Tegner scores. Both groups showed significantly improvement in these clinical function scores at follow up for their ACL reconstruction. However, there was no significant difference in the function scores between the two groups at last follow up. However, the mean femoral tunnel length in the anteromedial portal group was significantly shorter than that in the transtibial group. And tunnel location was significantly lower and deeper with the anteromedial portal technique than with the transtibial technique.

CONCLUSION

The use of anteromedial portal method resulted in a significantly lower and deeper placement of the femoral tunnel, and a shorter tunnel length compared to the transtibial method. However, there was no statistical difference in terms of clinical function and knee joint stability between the anteromedial portal method and the transtibial method.

TRIAL REGISTRATION

Name of the registry: Chinese Clinical Trial Registry. The registration number: ChiCTR1800014874 . The date of registration: 12 February, 2018. The study is retrospectively registered.

Femoral Tunnel Drilling Method: Risk of Reoperation and Revision After Anterior Cruciate Ligament Reconstruction

BACKGROUND

The femoral tunnel in anterior cruciate ligament reconstruction (ACLR) can be created by the transtibial (TT) or tibial-independent (TI) methods. An anatomically located femoral tunnel can be more consistently achieved by TI methods, which include the anteromedial portal and lateral (outside-in, retrodrill) techniques. Nonanatomic graft placement in ACLR can result in postoperative instability and meniscal or chondral injury. An anatomically located graft is subjected to higher postoperative physiologic forces than one placed nonanatomically.

PURPOSE

To examine isolated primary ACLR and determine the risk of aseptic revision and reoperation based on femoral tunnel drilling method.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

The ACLR registry of an integrated US health care system was used to identify primary isolated unilateral ACLRs from 2009 to 2014. Multivariable Cox proportional hazard regression models were used to evaluate risk for aseptic revision for graft failure and aseptic reoperation for meniscal or chondral injury according to femoral tunnel drilling method: TI versus TT. Models included age, sex, body mass index (BMI), race, graft type, and femoral fixation type as covariates.

RESULTS

The cohort included 19,059 patients with primary ACLR. The mean age was 28.9 years (SD, 11.5), 6991 patients (36.8%) were younger than 22 years, 11,795 patients (61.9%) were male, 7648 patients (40.1%) had a BMI less than 25 kg/m², 8913 patients (46.8%) were white, and 7357 patients (38.6%) received an allograft. Median follow-up was 2.30 years (interquartile range, 1.08-3.77). TI techniques were used for 12,342 (64.8%) of the ACLRs, and the TT method was used for 6717 (35.2%). Use of TI techniques increased from 33.6% of all ACLRs in 2009 to 83.4% in 2014. After adjustment for covariates, the TI group had a higher risk for aseptic revision than the TT group (hazard ratio [HR], 1.28; 95% CI, 1.04-1.56), and this risk was 1.41 times higher in patients younger than 22 years specifically. The 5-year cumulative reoperation probability was lower in the TI group (4.50%; 95% CI, 3.78%-5.36%) compared with the TT group (5.06%; 95% CI, 4.31-5.94%). After adjustment for the covariates, no difference in risk for aseptic reoperation was observed (HR, 1.08; 95% CI, 0.85-1.39).

CONCLUSION

In the largest known study of its type examining femoral tunnel drilling method for primary ACLR, after adjustment for age, sex, BMI, race, graft type, and femoral fixation, TI techniques were found to carry higher risk of aseptic revision compared with the TT method, while no difference was observed in risk for aseptic reoperation.

Hyperflexion and Femoral Interference Screw Insertion in ACL Reconstruction

Background:

In anatomic anterior cruciate ligament (ACL) reconstructions produced with flexible reamers and no knee hyperflexion, it is unknown whether knee hyperflexion is necessary for femoral interference screw insertion.

Purpose:

To compare femoral screw-graft divergence in anatomic ACL reconstructions with endoscopic interference screws placed without knee hyperflexion and with the use of flexible versus rigid screwdrivers.

Study Design:

Controlled laboratory study.

Methods:

Ten matched pairs of cadaveric knees had bone-tendon-bone graft ACL reconstructions with anatomic femoral tunnels. The knees were flexed to 90°. Femoral interference screws (7 × 20 mm) were placed in pairs of knees: in 1 knee with a flexible screwdriver and in the opposite knee with a rigid screwdriver. Graft-screw divergence was imaged with computed tomography scans and tested with cyclic and static biomechanical tests.

Results:

The mean screw-graft divergence was 12.07° ± 4.04° with the rigid screwdriver and 10.68° ± 3.23° with the flexible screwdriver (P = .35). The cyclic tests with screws placed by a rigid screwdriver had a mean increase in displacement of 0.56 ± 0.20 mm. For screws placed with the flexible screwdriver, the mean increase in displacement was 0.58 ± 0.32 mm (P = .66). Yield load was 393.3 ± 95.1 N for screws placed by a rigid screwdriver and 408.2 ± 119.0 N for screws inserted with the flexible screwdriver (P = .78). Maximum load was 523.1 ± 88.7 N for screws placed by a rigid screwdriver and 467.1 ± 107.3 N for screws inserted with the flexible screwdriver (P = .09).

Conclusion:

With either a rigid or a flexible screwdriver, there were no significant effects on screw divergence or fixation strength.

Clinical Relevance:

Knees can be kept at 90° during endoscopic femoral interference screw insertion. The use of a traditional rigid or flexible screwdriver will not affect screw-graft divergence or fixation strength.

Anterior Laxity at 2 Years After Anterior Cruciate Ligament Reconstruction Is Comparable When Using Adjustable-Loop Suspensory Fixation and Interference Screw Fixation

BACKGROUND

Adjustable-loop suspensory fixation (ALSF) devices are commonly used in anterior cruciate ligament reconstruction (ACLR). However, concern exists regarding the potential for lengthening under cyclical loads.

PURPOSE

To compare the residual anterior laxity of 2 methods of femoral fixation, ALSF versus interference screw fixation, in patients undergoing isolated ACLR in the absence of meniscal injuries. To determine the preoperative risk factors associated with residual postoperative anterior laxity.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis was performed comparing 2 groups of patients that underwent primary ACLR using ALSF versus bioabsorbable interference screw fixation. Anterior knee laxity was assessed with Telos stress radiography, while functional outcomes were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity level scale at a minimum of 2 years postoperatively. A multivariate analysis was performed to identify factors associated with residual postoperative laxity >3 mm.

RESULTS

Of the 1136 patients who underwent ACLR during the study period, 363 met the inclusion criteria. A total of 272 patients (75%) (mean age, 31.7 ± 10.7 years) with a mean follow-up of 25.7 ± 4.6 months (range, 24-36 months) consented to participate (screw group: n = 121; ALSF group: n = 151). The 2 groups were statistically comparable in terms of age, sex ratio, time from injury to surgery, graft diameter, preoperative laxity, preoperative objective International Knee Documentation Committee (IKDC) grade, and preoperative Tegner score. The mean postoperative laxity as a continuous variable was significantly different comparing the ALSF and screw groups (1.49 ± 1.98 mm and 2.32 ± 1.97 mm, respectively; P < .001). In the screw group, 76 patients (62.8%) had normal (<3 mm), 40 (33.1%) had nearly normal (3-6 mm), and 5 (4.1%) had abnormal (≥6 mm) postoperative knee laxity according to the IKDC grade, while in the ALSF group, 112 patients (74.2%) had normal, 37 (24.5%) had nearly normal, and 2 (1.3%) had abnormal laxity ( P = .0833). No significant difference was found in KOOS or Tegner scores comparing the 2 femoral fixation methods: KOOS, 90.6 ± 7.5 (ALSF group) and 90.6 ± 7.4 (screw group) ( P = .7631), versus Tegner, 6.5 ± 1.3 (ALSF group) and 6.3 ± 1.4 (screw group) ( P = .2992). A negative correlation was found between postoperative laxity and final Tegner ( r_s = -0.303, P < .001) and KOOS scores ( r_s = -0.168, P = .005). The initial univariate analysis showed differences between groups of patients with residual knee laxity ≥3 mm and <3 mm on preoperative pivot shift, preoperative laxity, age, fixation type, and preoperative objective IKDC grade. The multivariate analysis on these factors showed that the pivot shift remained the only significant predictor for residual laxity ≥3 mm for pivot shift grade 2 compared with grade 1 (odds ratio, 4.689 [95% CI, 2.465-9.286]) and for pivot shift grade 3 compared with grade 1 (odds ratio, 58.025 [95% CI, 12.757-557.741]) ( P < .001).

CONCLUSION

For primary ACLR, the use of an ALSF device for femoral fixation is associated with noninferior postoperative anterior knee laxity results compared with interference screw fixation at a minimum 2 years' follow-up. The preoperative pivot shift is the only significant risk factor for postoperative residual anterior knee laxity >3 mm.

Minimizing Graft-Tunnel Mismatch in Allograft Anterior Cruciate Ligament Reconstruction Using Blumensaat's Line: A Cadaveric Study

PURPOSE

To evaluate the accuracy of Blumensaat's line (BL) in predicting the tendinous graft length and tibial tunnel length (TTL) in an independent-tunnel anterior cruciate ligament reconstruction (ACLR) using a bone-patellar tendon-bone (BTB) allograft.

METHODS

Eighteen ACLRs were performed on cadaveric specimens using an anteromedial portal technique. All knees had no previous surgeries or deformities. Lateral knee radiographs of each specimen were taken prior to the ACLR, and BL was measured. Length-specific allografts for the tendinous portion of the grafts were then ordered by adding 20 mm to the length of BL. The TTL was predicted by subtracting BL and femoral tunnel length (FTL) from the overall graft length. Graft-tunnel mismatch (GTM) was recorded for each specimen. Statistical analysis compared overall results with the gold standard (0 mm) of GTM.

RESULTS

The average lateral femoral condyle width measured in line with the femoral tunnel was 33 ± 3.43 mm. The average FTL was 25 ± 0.54 mm. The average intra-articular distance (IAD) between femoral and tibial tunnel apertures was 31 ± 3.65 mm. The average TTL was 35 ± 2.21 mm. The difference between the predicted TTL and the actual TTL was not statistically significant (P = .3). The mean GTM was -0.9 ± 3.15 mm. There was no statistically significant difference between the BL method and the gold standard (P = .45). The mean percent difference between BL and the IAD was 5.2%.

CONCLUSIONS

The BL method can accurately predict the desired length for the tendinous portion of a BTB allograft as well as the TTL, thereby potentially minimizing GTM during arthroscopic BTB allograft ACLR. Patient-specific allografts can be ordered preoperatively based on BL.

CLINICAL RELEVANCE

This method provides the surgeon a way to avoid GTM preoperatively by ordering patient-specific grafts prior to performing an independent-tunnel BTB allograft ACLR.

Expression of Signaling Molecules Involved in Embryonic Development of the Insertion Site Is Inadequate for Reformation of the Native Enthesis: Evaluation in a Novel Murine ACL Reconstruction Model

BACKGROUND

Since healing of anterior cruciate ligament (ACL) grafts occurs by formation of a fibrovascular scar-tissue interface rather than by reformation of the native fibrocartilage transition zone, the purpose of our study was to examine expression of various signaling molecules and transcription factors that are known to be involved in embryologic insertion-site development following ACL reconstruction. We also aimed to characterize a murine model of ACL reconstruction to allow future study of the molecular mechanisms of healing.

METHODS

Seventy-nine mice underwent reconstruction of the ACL with autograft. Healing was assessed using histology in 12 mice and quantitative real-time polymerase chain reaction (qRT-PCR) gene-expression analysis in 3 mice at 1 week postoperatively (Group-1 mice) and by biomechanical analysis in 7, histological analysis in 7, immunohistochemical analysis in 5, microcomputed tomography analysis in 5, and qRT-PCR analyses in 8 at 2 weeks (Group-2 mice) and 4 weeks (Group-3 mice) postoperatively. Fifteen additional mice did not undergo surgery and were used for biomechanical (7 mice), qRT-PCR (3 mice), and immunohistochemical (5 mice) analyses to obtain baseline data for the native ACL.

RESULTS

Histological analysis demonstrated healing by formation of fibrovascular tissue at the tendon-bone interface. Immunohistochemical analysis showed a positive expression of proteins in the Indian hedgehog, Wnt, and parathyroid hormone-related protein (PTHrP) pathways. There was minimal Sox-9 expression. Gene-expression analysis showed an initial increase in markers of tissue repair and turnover, followed by a subsequent decline. Mean failure force and stiffness of the native ACL were 5.60 N and 3.44 N/mm, respectively. Mean failure force and stiffness were 1.29 N and 2.28 N/mm, respectively, in Group 2 and were 1.79 N and 2.59 N/mm, respectively, in Group 3, with 12 of 14 failures in these study groups occurring by tunnel pull-out.

CONCLUSIONS

The spatial and temporal pattern of expression of signaling molecules that direct embryologic insertion-site formation was not adequate to restore the structure and composition of the native insertion site.

CLINICAL RELEVANCE

Development of a murine model to study ACL reconstruction will allow the use of transgenic animals to investigate the cellular, molecular, and biomechanical aspects of tendon-to-bone healing following ACL reconstruction, ultimately suggesting methods to improve healing in patients.

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.

High incidence of partially anatomic tunnel placement in primary single-bundle ACL reconstruction

PURPOSE

The purpose of this study was to evaluate tunnel position and width in failed primary single-bundle (SB) anterior cruciate ligament (ACL) reconstructions. It was hypothesized that both femoral and tibial bone tunnels are frequently malplaced in terms of a partially anatomic position in the setting of failed SB ACL reconstruction.

METHODS

Patients with recurrent instability following isolated SB ACL reconstruction using hamstring tendon autografts, undergoing revision ACL surgery, were retrospectively included. Further inclusion criteria were age >18 years and availability of preoperative computed tomography (CT) scans and radiographs of the affected knee. Patients with multiligamentous instabilities as well as incomplete or poor radiographs were excluded. Tunnel position was evaluated according to the method described by Harner et al. and Stäubli and Rauschning. Tunnel width was determined on CT scans perpendicular to the bone tunnel axis at three different heights of each bone tunnel.

RESULTS

Eighty-two patients met the inclusion criteria and were considered for radiological analysis. Femoral tunnels were graded as anatomic in 60% (49 of 82) of all cases. In the remaining 40% (33/82), 27% of the tunnels were placed partially anatomic and 13% were graded as non-anatomic. Tibial tunnel placement was found to be anatomic in 54% (44/82) of all cases, partially anatomic in 45% and non-anatomic in 1% of the cases. No statistically significant difference between anatomic or partially anatomic tunnel position and tunnel diameter, neither for the femoral nor for the tibial side, was observed (n.s.).

CONCLUSION

The present study demonstrates that there is a high incidence of partially anatomic placed tunnels in failed SB ACL reconstruction. Tunnel width was not associated with tunnel position. Clinically, partially anatomic bone tunnels frequently require a staged procedure with bone grafting and subsequent ACL revision surgery. Thus, surgeons should carefully analyse tunnel position and width preoperatively to properly plan ACL revision surgery.

Anteromedial versus transtibial technique in single-bundle autologous hamstring ACL reconstruction: a meta-analysis of prospective randomized controlled trials

Background

The aim of this study was to compare the clinical outcome and postoperative complication between single-bundle anterior cruciate ligament (ACL) reconstruction with an anteromedial (AM) technique and a transtibial (TT) technique.

Methods

The study includes clinical randomized controlled trials comparing the clinical outcomes of ACL reconstruction using the autologous hamstring tendon with an AM method and a TT method published up to September 2017 were retrieved from PubMed, Cochrane Library, and Embase databases. Relevant data were extracted and the Physiotherapy Evidence Database (PEDro) scale was used to assess the methodological quality. Stata/SE 12.0 was used to perform a meta-analysis of the clinical outcome.

Results

Five RCTs were included, with a total of 479 patients: 239 patients and 240 patients in the AM group and the TT group, respectively. Assessing postoperative stability, better results were found in the AM group for the negative rate of the Lachman test (P < 0.05), the negative rate of the pivot-shift test (P < 0.05) and the side-to-side difference (P < 0.05). Assessing postoperative functional outcome, the AM group yielded superior results in proportion with International Knee Documentation Committee (IKDC) grade A (P < 0.05) and the Lysholm scores (P < 0.05) but had a comparable IKDC score (P > 0.05). In terms of postoperative complication, no significant difference was found between the AM group and the TT group (P > 0.05).

Conclusions

The outcome of single-bundle ACL reconstruction with the AM technique is better than that with the TT technique in terms of postoperative stability and functional recovery of the knee.

Tunnel positioning assessment after anterior cruciate ligament reconstruction at 12months: Comparison between 3D CT and 3D MRI. A pilot study

BACKGROUND

Tunnel positioning assessment is a major issue after anterior cruciate ligament (ACL) reconstruction surgery. Historically, it used plain X-ray and, more recently, CT with 3D reconstruction. MRI is a reliable method of assessing ACL graft integrity and postoperative complications. To our knowledge, there have been no studies of efficacy in tunnel positioning assessment. The aim of this study was to assess the efficacy of 3D MRI in assessing femoral and tibial tunnel positioning after ACL reconstruction. The hypothesis was that 3D MRI sequences with reconstruction are as accurate as 3D CT for tunnel positioning assessment in ACL reconstruction.

METHODS

Twenty-two patients who underwent an arthroscopic ACL reconstruction using hamstring graft were included in a prospective study. All patients were examined on 3D CT and 3D MRI at 12months post-surgery. Tunnel positioning was assessed on both imaging systems by a musculoskeletal radiologist and an orthopedic surgeon specialized in knee arthroscopy, both blind to all clinical data.

RESULTS

No statistically significant difference was found between 3D CT and 3D MRI on coronal and sagittal reconstructions. For coronal assessment of tibial tunnel orifice, sagittal assessment of tibial tunnel orifice and sagittal assessment of femoral tunnel orifice, P-values ranged from 0.37 to 0.99, 0.051 to 0.64 and 0.19 to 0.59, respectively. For tibial and femoral tunnel angulation, P-values were respectively 0.52 and 0.29.

CONCLUSION

3D MRI is a reliable method to assess femoral and tibia tunnel positioning in ACL reconstruction, compared to 3D CT as gold standard. Indeed, in our opinion 3D MRI could in the future replace CT for ACL reconstruction assessment, concerning not only the meniscus and ligaments but also tunnel position.

LEVEL OF EVIDENCE

Level 3; comparative prospective study.

Timing of Postoperative Mechanical Loading Affects Healing Following Anterior Cruciate Ligament Reconstruction: Analysis in a Murine Model

BACKGROUND

Following anterior cruciate ligament (ACL) reconstruction, the mechanical loading of the tissues has a significant impact on tendon-to-bone healing. The purpose of this study was to determine the effect of the timing of the initiation of mechanical loading on healing of a tendon graft in a bone tunnel.

METHODS

ACL reconstruction using a flexor tendon autograft was performed in 56 mice randomized to 4 groups with differing times to initiation of postoperative mechanical loading: (1) immediate, (2) 5 days, (3) 10 days, or (4) 21 days following surgery. An external fixator was placed across the knee at the time of surgery and removed when mechanical loading was scheduled to commence. Following removal of the external fixator, animals were permitted free, unrestricted cage activity. All mice were killed on postoperative day 28, and tendon-to-bone healing was assessed by biomechanical testing, microcomputed tomography (micro-CT), and histological analysis.

RESULTS

The mean failure force (and standard deviation) of the reconstructed ACL at the time of sacrifice was highest for Group 2 (3.29 ± 0.68 N) compared with Groups 1, 3, and 4 (p = 0.008). Micro-CT bone volume fraction was greatest for Group 2 in the femoral tunnel (p = 0.001), tibial tunnel (p = 0.063), and both bones (p < 0.001). Similarly, histological analysis demonstrated a narrower scar tissue interface and increased direct contact at the tendon-bone interface (p = 0.012) for Group 2.

CONCLUSIONS

Following ACL reconstruction, a defined period of immobilization without weight-bearing appears to improve biomechanical strength of the healing tendon-bone interface, while prolonged periods without mechanical load and motion decrease the ultimate load to failure in this murine model.

CLINICAL RELEVANCE

The ideal period of restricted weight-bearing and motion following ACL reconstruction remains undefined. In a murine model, improved healing was noted for animals immobilized for a brief period of 5 days. This work may serve as an initial step in determining the ideal time period in a clinical population.

Three dimensionalCT analysis of femoral tunnel position after ACL reconstruction. A prospective study of one hundred and thirty five cases

BACKGROUND

One of the principal causes for failure of anterior cruciate ligament reconstruction (ACL) is femoral tunnel mal-position. Several studies compare the position of femoral tunnels achieved with various techniques, with small series and using a quadrant assessment method.

QUESTIONS

(1) What is the incidence of anatomical positioning of the intra-articular femoral tunnel aperture in primary ACL reconstruction in a university knee surgery? (2) What are the main errors in positioning?

METHODS

3D-CT scans were performed after primary ACL reconstruction in 135 consecutive cases. The intra-articular position of the femoral tunnel aperture was analyzed using the Magnussen classification.

RESULTS

The intra-articular tunnel position was deemed anatomical in 77%, intermediate in 20.8%, and non-anatomical in 2.2%. Among the mal-positioned tunnels, 54.8% were vertical, 29% were anteriorly positioned, and 16.1% were both.

CONCLUSIONS

The intra articular femoral tunnel aperture was well positioned using an outside-in technique. The main error of tunnel positioning was a tunnel too vertical.

LEVEL OF EVIDENCE

Level III, prospective study (case series).