Knee stability and graft function following anterior cruciate ligament reconstruction: Comparison between 11 o'clock and 10 o'clock femoral tunnel placement. 2002 Richard O'Connor Award paper

Limb Deformity Caused by Distal Femoral and Proximal Tibial Growth Arrest After ACL Reconstruction in a Child: A Case Report

CASE

We report the case of a twelve-year-old boy with limb deformity caused by physeal closure after transphyseal intra-articular reconstruction of the anterior cruciate ligament of the left knee at the age of seven years. We treated premature closure of the physis with a Langenskiöld procedure. Lengthening and correction of the deformity were accomplished with use of the Ilizarov method. Although gross instability remained, reasonable limb alignment was attained with prolonged treatment.

CONCLUSION

We document growth arrest and severe limb deformity after transepiphyseal anterior cruciate ligament reconstruction with an artificial polyester ligament and successful surgical correction.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

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

The Apex of the Deep Cartilage: A Landmark and New Technique to Help Identify Femoral Tunnel Placement in Anterior Cruciate Ligament Reconstruction

PURPOSE

The purpose of this study was to evaluate the apex of the deep cartilage (ADC) as a landmark to help guide femoral tunnel placement during anatomic single-bundle anterior cruciate ligament (ACL) reconstruction. Our secondary purpose was to assess whether or not the endoscopic transtibial femoral offset drill guide could reach the center of the ACL's femoral footprint.

METHODS

Eight formalin-injected cadaveric knees were dissected and the center of the ACL femoral footprints identified. The ADC was selected as an easily identifiable landmark during arthroscopy and was used to reference the position of the ACL femoral footprint with the knee flexed at 90°. Next, a 7-mm transtibial femoral ACL drill guide was used to engage the posterior aspect of the lateral condyle at the level of the femoral footprint. This position was marked, and the distance from the center of the femoral footprint was recorded for each specimen. Descriptive statistics were used to report our measurements.

RESULTS

The median high and shallow measurements were 3 mm (range, 1 to 4 mm) and 12 mm (range, 11 to 17 mm), respectively. The femoral offset guide never reached the center of the femoral footprint in all specimens; the median distance between the 2 measurements was 4.5 mm (range, 2 to 9 mm).

CONCLUSIONS

If the anatomy is difficult to delineate at the time of reconstruction, our study suggests using the ADC as a landmark to guide anatomic placement. The dissection of 8 cadavers showed that the center of the ACL femoral footprint had a median position of 3 mm high and 12 mm shallow to the ADC. We also showed that the transtibial femoral offset guide did not reach the center of the ACL footprint on all specimens and should therefore not be used for anatomic ACL reconstruction.

CLINICAL RELEVANCE

Current commercially available transtibial femoral offset guides cannot reach the center of the ACL's femoral footprint and therefore should not be used. Alternative techniques, such as referencing from the ADC through an anteromedial (AM) portal, are recommended.

Single-bundle modified patellar tendon versus double-bundle tibialis anterior allograft ACL reconstruction: a prospective randomized study

PURPOSE

The purpose of this study was to prospectively compare the outcomes of single-bundle (SB) anterior cruciate ligament (ACL) reconstruction with modified bone-patellar tendon-bone (BPTB) allograft and double-bundle (DB) reconstruction with tibialis anterior allograft.

METHODS

With 94 patients enroled in the study, 43 subjects who had SB ACL reconstruction with modified BPTB allograft (group S) and 41 subjects of DB ACL reconstruction with tibialis anterior allograft (group D) were followed up for a minimum of 2 years. Clinical outcomes including Lachman and pivot-shift tests, KT-1000 arthrometer measurements, and the International Knee Documentation Committee (IKDC) classification, Lysholm and Tegner activity scores were compared between the two groups at the last follow-up.

RESULTS

The mean graft size of the group S, the anteromedial bundle and posterolateral bundle in group D were 9.9 ± 0.2, 7.5 ± 0.4 and 6.6 ± 0.4 mm, with statistically significant difference between the group S graft to either bundle of group D grafts (p < 0.001). At the last follow-up, there was no statistical difference between the two groups for the Lachman test, pivot-shift test and side-to-side difference. Substantial improvements in the subjective knee function scores were achieved in both groups, but without significant difference between the two groups.

CONCLUSIONS

After a 2-year minimum follow-up, SB ACL reconstruction based on modified BPTB allograft achieved similar clinical outcomes to DB reconstruction with tibialis anterior allograft in knee stability, both anterior-posterior and rotational, as well as knee function. The modified BPTB allograft was recommended as an ideal graft option for the SB ACL reconstruction.

LEVEL OF EVIDENCE

Therapeutic, randomized controlled study, Level II.

Computer-assisted anterior cruciate ligament reconstruction. Four generations of development and usage

The purpose of this paper is to review the literature about the contribution of navigation in anterior cruciate ligament (ACL) reconstruction. The evolution of computer-assisted surgery (CAS) for ACL reconstruction has undergone several steps. These steps were divided into 4 subsequent developments: (1) positioning of ACL graft placement; (2) laxity measurement of ACL reconstruction (quality control); (3) kinematic evaluation during ACL reconstruction (navigated pivot shift); (4) case-specific individual ACL reconstruction with adjustments and additional reconstruction options. CAS has shown to improve femoral tunnel positioning, even if clinical outcomes do not improve results of manual techniques. CAS technology has helped researchers better understand the effects of different ACL reconstruction techniques and bundles replacements on joint laxity and to describe tunnel positioning in relation to native ACL insertion. CAS in ACL surgery can improve results at time zero and can improve knowledge in this field.

Evaluating the distance between the femoral tunnel centers in anatomic double-bundle anterior cruciate ligament reconstruction using a computer simulation

Purpose

We aimed to clarify the distance between the anteromedial (AM) bundle and posterolateral (PL) bundle tunnel-aperture centers by simulating the anatomical femoral tunnel placement during double-bundle anterior cruciate ligament reconstruction using 3-D computer-aided design models of the knee, in order to discuss the risk of tunnel overlap. Relationships between the AM to PL center distance, body height, and sex difference were also analyzed.

Patients and methods

The positions of the AM and PL tunnel centers were defined based on previous studies using the quadrant method, and were superimposed anatomically onto the 3-D computer-aided design knee models from 68 intact femurs. The distance between the tunnel centers was measured using the 3-D DICOM software package. The correlation between the AM–PL distance and the subject’s body height was assessed, and a cutoff height value for a higher risk of overlap of the AM and PL tunnel apertures was identified.

Results

The distance between the AM and PL centers was 10.2±0.6 mm in males and 9.4±0.5 mm in females (P<0.01). The AM–PL center distance demonstrated good correlation with body height in both males (r=0.66, P<0.01) and females (r=0.63, P<0.01). When 9 mm was defined as the critical distance between the tunnel centers to preserve a 2 mm bony bridge between the two tunnels, the cutoff value was calculated to be a height of 160 cm in males and 155 cm in females.

Conclusion

When AM and PL tunnels were placed anatomically in simulated double-bundle anterior cruciate ligament reconstruction, the distance between the two tunnel centers showed a strong positive correlation with body height. In cases with relatively short stature, the AM and PL tunnel apertures are considered to be at a higher risk of overlap when surgeons choose the double-bundle technique.

Effect of Different Preconditioning Protocols on Anterior Knee Laxity After ACL Reconstruction with Four Commonly Used Grafts

BACKGROUND

It is currently unknown if preconditioning an anterior cruciate ligament (ACL) graft prior to fixation is helpful in eliminating possible increases in anterior knee laxity. The purpose of this study was to measure cyclic increases in anterior tibial translation of four commonly used graft tissues subjected to four preconditioning protocols.

METHODS

A robotic system was used to apply 250 cycles of anteroposterior force (134 N of anterior force followed by 134 N of posterior force) to ten intact knees (ACL controls) and then to a single knee reconstructed, for separate tests, with bone-patellar tendon-bone, bone-Achilles tendon, hamstring tendon, and tibialis tendon grafts following (1) no preconditioning, (2) preconditioning on a tension board (89 N of initial force held for twenty minutes), (3) preconditioning in situ (89 N of force applied to the tibial end of the graft during twenty-five flexion-extension cycles), and (4) a combination of protocols 2 and 3.

RESULTS

Over the 250 cycles, all grafts were associated with a progressive increase in anterior tibial translation that was approximately an order of magnitude greater than that of the ACL, and preconditioning had no significant effect on this increase in translation. There were some significant differences in the progressive anterior tibial translation increase among the graft tissues within a given preconditioning protocol, but these differences were no greater than 1.1 mm. First-cycle and cycle-250 anterior tibial translation varied among the graft tissue types, possibly reflecting an initial "settling in" process. Regardless of the tissue type, ≥75% of the total increase in the anterior tibial translation occurred within the first 125 cycles.

CONCLUSIONS

Preconditioning had no significant effect on the progressive increase of anterior tibial translation from the first cycle to cycle 250 for any of the graft tissues tested.

CLINICAL RELEVANCE

On the basis of these results, current preconditioning methods appear to be ineffective in reducing progressive increases in anterior knee laxity from cyclic loading.

Dynamic Effect of Quadriceps Muscle Activation on Anterior Tibial Translation After Single-Bundle and Double-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

To examine differences in anterior tibial translation in 3 groups: single-bundle anterior cruciate ligament (ACL)-reconstructed, double-bundle ACL-reconstructed, and ACL-intact knees under gradual dynamic quadriceps muscle activation.

METHODS

Thirty male patients underwent successful single-bundle (n = 15) and double-bundle (n = 15) ACL reconstructions; 15 healthy controls were included in the study. Anterior tibial translation was assessed at 30° of knee flexion in the resting position (0% quadriceps activation) and under 50% and 100% of maximum quadriceps concentric contraction using an isokinetic dynamometer with the KT-2000 arthrometer securely attached to the participants' knees.

RESULTS

The 2 ACL-reconstructed groups were similar regarding International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Score (KOOS), Tegner, and Lysholm scores and preliminary isokinetic evaluation (P = .38). Quadriceps activation significantly affected anterior tibial translation (P = .001, α = 0.98). In all 3 study groups, anterior tibial translation was significantly higher under 100% quadriceps activation compared with 0% contraction (P = .01) and 50% quadriceps activation (P = .047). There were no between-group differences in anterior tibial translation with 0%, 50%, or 100% quadriceps activation (P = .46).

CONCLUSIONS

Under quadriceps muscle activation, anteroposterior knee laxity in ACL-intact and ACL-reconstructed knees is gradually increased. Single-bundle and double-bundle ACL-reconstructed knees show a similar increase in anterior tibial translation under gradual quadriceps contraction. When comparing different ACL reconstruction techniques in the experimental setting, dynamic, in addition to static, testing is advised to reach a comprehensive assessment of anteroposterior knee stability.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Clinical Outcomes After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: Comparison of Extreme Knee Hyperextension and Normal to Mild Knee Hyperextension

PURPOSE

The aim of this study was to compare postoperative outcomes after anatomic double-bundle anterior cruciate ligament reconstruction (ACLR) in extreme knee hyperextension versus normal to mild knee hyperextension.

METHODS

For 100 patients who underwent anatomic double-bundle ACLR using semitendinosus tendon, we evaluated the side-to-side difference (SSD) in anterior tibial translation (measured on stress radiographs) and rotational stability (assessed by the pivot-shift test) 2 years after surgery. Loss of extension (LOE) was evaluated on lateral radiographs of both knees in full extension, and graft integrity was assessed during second-look arthroscopy 1 to 2 years after surgery. In accordance with the Beighton and Honan criteria, patients with an extension angle less than or equal to 10° in the contralateral uninjured knee composed the group with 10° or less hyperextension (N group), and those with an extension angle of greater than 10° composed the group with more than 10° hyperextension (H group). Postoperative results were compared between these groups.

RESULTS

Mean extension angles in the N and H groups were 5.8° ± 2.9° and 14.7° ± 3.0°, respectively. The mean SSD in anterior translation was 2.2 ± 2.9 mm for the N group and 2.8 ± 2.9 mm for the H group, with no significant difference. The positive ratios on the pivot-shift test were not significantly different between the groups. Mean LOE in the N and H groups was -0.7° ± 3.7° and 1.3° ± 3.3°, respectively, with a significant difference (P = .007). During second-look arthroscopy, 6 of 58 knees in the N group and 13 of 42 knees in the H group had superficial graft laceration of the anteromedial bundle graft, with a significant difference (P = .01) seen between groups.

CONCLUSIONS

Anatomic double-bundle ACLR for extreme knee hyperextension may attain the same postoperative anterior and rotational stability as seen in knees with normal to mild hyperextension. However, it increased superficial graft laceration.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Excursion of bone-patella tendon-bone grafts during the flexion-extension movement in anterior cruciate ligament reconstruction: Comparison between isometric and anatomic reconstruction techniques

Background/objective

The purpose of this study was to elucidate the biomechanical differences between anterior cruciate ligament (ACL) grafts reconstructed by isometric and anatomic reconstruction techniques, based on their length changes.

Methods

One hundred and thirty-three knees with primary ACL reconstruction using the bone-patellar tendon-bone (BTB) graft were retrospectively identified. Twenty-two knees and 111 knees underwent isometric round tunnel (IRT) ACL reconstruction and anatomic rectangular tunnel (ART) ACL reconstruction, respectively.

Results

After femoral-side fixation of the graft in the surgery, the length change of the graft from 120° flexion to full extension was measured by using an isometric positioner at the tibial side. Both reconstructive techniques showed little length change from 120° to ∼20° of flexion, followed by elongation of the graft, until full extension. The amount of length change of the grafts was 1.0 ± 0.7 mm with the IRT technique, and 3.4 ± 0.9 mm with the ART technique. These findings were significantly different, based on the Mann–Whitney U test (p < 0.001).

Conclusion

The native ACL has an intrinsic length change of 3–6 mm, and therefore the ART technique may more closely replicate the biomechanical function of the native ACL.

Can we use intraoperative femoral tunnel length measurement as a clue for proper femoral tunnel placement on coronal plane during ACL reconstruction?

INTRODUCTION

Successful anterior cruciate ligament (ACL) reconstruction is dependent on correct placement of both tibial and femoral tunnels. The purpose of this study is to investigate whether we can use intraoperative femoral tunnel length measurement to estimate the correct femoral tunnel placement on coronal plane.

METHODS

This prospective study comprised 164 consecutive patients who underwent ACL reconstruction surgery. Transtibial or anteromedial portal technique is used for drilling the femoral tunnels. The length of the femoral tunnel was measured during the operation. The femoral tunnel coronal plane angle was calculated on the postoperative tunnel radiographs. A statistical comparison was made of the lengths of the tunnel, the techniques used drilling and the femoral tunnel angles.

RESULTS

The far anteromedial portal was used in 81 (49%) cases and the transtibial technique in 83 (51%) cases. The mean femoral tunnel length was 42 ± 6.4 mm and the mean femoral tunnel coronal angle was 41.1° ± 11.6. The tunnel angle in the transtibial technique was determined as significantly low compared to the far anteromedial portal technique (32.6°:49.8°) and the tunnel length was significantly longer (45.8:38.1 mm) (p < 0.001). In the statistical analysis, it was found that a patient with a tunnel length of 41 mm and above had a 92.1% likelihood of femoral tunnel angle below 45°.

CONCLUSION

Femoral tunnel length can be used as a clue for intraoperative evaluation of the femoral tunnel position. If the femoral tunnel length is greater than 41 mm, the coronal plane orientation of the femoral tunnel will be improper and not at a desired position.

Farmedial versus anteromedial portal drilling of the femoral tunnel in ACL reconstruction: a computed tomography analysis

INTRODUCTION

The success of ACL reconstruction is predicated on a variety of factors. Tunnel placement plays one of the most significant roles in achieving knee kinematics and function. The purposes of this study were to compare femoral tunnel position, angle, length and posterior wall blow-out after ACL reconstruction with hamstring tendons autograft through either a farmedial portal or an anteromedial portal technique.

MATERIALS AND METHODS

We evaluated 36 patients who underwent ACL reconstruction between January 2014 and July 2014 in our institute, in a prospective, randomised cohort study. All the surgical procedures were performed by a sports fellowship-trained orthopaedic surgeon with experience in both portal reaming. The operated knees were evaluated with 0.5 mm fine CT scans of 3-D CT between days 3 and 5 postoperatively.

RESULTS

According to the 3-D CT measurements, the mean femoral tunnel length was significantly longer (p < 0.05) in the FAM group compared with the AM group. The femoral bone tunnel length averaged 34.2 ± 3.6 mm versus 36.6 ± 3.0 mm (p = 0.042) in AM and the FAM groups, respectively. The femoral tunnel position, as evaluated with use of the quadrant method, was more anterior in the FAM transportal technique group, and the difference between the two groups was significant (p < 0.05).

CONCLUSION

FAM tranportal drilling of the femoral tunnel creates longer and anterior femoral tunnels with regard to the AM portal drilling techniques. Additional studies with clinical outcomes are required for the clinical relevance of these techniques and to show which one is superior.

LEVEL OF EVIDENCE

Level I, prospective randomised comparative cohort study.

Size correlation between the tibial anterior cruciate ligament footprint and the tibia plateau

PURPOSE

The purpose of this study was to reveal the correlation between the size of the native anterior cruciate ligament (ACL) footprint and the size of the tibia plateau.

METHODS

Twenty-four non-paired human cadaver knees were used. All soft tissues around the knee were resected except the ACL. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch. The ACL was carefully dissected, and the periphery of the ACL insertion site was outlined on both the femoral and tibial sides. An accurate lateral view of the femoral condyle and the tibial plateau was photographed with a digital camera, and the images were downloaded to a personal computer. The size of the femoral and tibial ACL footprints, and anterior-posterior (AP) and medial-lateral (ML), lengths of the tibia plateau and area of tibia plateau were measured with Image J software (National Institution of Health).

RESULTS

The sizes of the native femoral and tibial ACL footprints were 72.3 ± 24.4 and 134.1 ± 32.4 mm(2), respectively. The AP lengths of the whole, medial and lateral facet of the tibia plateau were as follows: 44.5 ± 4.1, 40.8 ± 4.1 and 36.8 ± 4 mm, respectively. The ML length of the tibia plateau was 68.3 ± 5.5 mm. Total area of tibia plateau was 2,282.9 ± 378.7 mm(2). The AP length of the lateral facet of the tibia plateau (Pearson's correlation coefficient = 0.508, p = 0.011) and the total area of tibia plateau (Pearson's correlation coefficient = 0.442, p = 0.031) were significantly correlated with the size of the tibial ACL footprint.

CONCLUSION

For clinical relevance, the AP length of lateral facet of the tibia plateau and total area of tibia plateau are significantly correlated with the size of the tibial ACL footprint. It might be possible to predict the size of the ACL measuring these parameters.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Case series, Level IV.

Prospective randomized comparison of knee stability and joint degeneration for double- and single-bundle ACL reconstruction

PURPOSE

This study aims to determine the outcome of double-bundle anterior cruciate ligament (ACL) reconstruction using an allograft in comparison with ACL reconstruction using a double-bundle autograft or a single-bundle allograft.

METHODS

A total of 424 patients who accepted primary ACL reconstructions were divided randomly into three groups: double-bundle technique with autograft (DB-AU group, n = 154), double-bundle technique with allograft (DB-AL group, n = 128), and single-bundle technique with allograft (SB group, n = 142). The KT-1000 arthrometer and pivot-shift tests were performed at 3, 12, and 36 months after surgery, and clinical outcome measurements include the Lysholm score and the IKDC rating scales. Radiological assessments evaluated arthritic changes and tunnel expansion at 36 months postoperatively.

RESULTS

The KT-1000 test scores in the DB-AU and DB-AL groups were significantly better than those in the SB group at 12 and 36 months postoperatively (P < 0.05). The pivot-shift tests scores in the DB-AU and DB-AL groups were significantly better than those in the SB group at the 3, 12, and 36 month follow-ups (P < 0.05). Based on the IKDC score and Lysholm score, there were no significant difference between the three groups during follow-up (P > 0.05). At 36 months postoperatively, 42.3 % of patients in the SB group showed a progression in arthritic changes, which was greater than in the DB-AU (29.2 %) and DB-AL (27.3 %) groups (P < 0.05). At 36 months, the rates of tunnel expansion in the DB-AU group and the DB-AL group were lower than in the SB group (P < 0.05).

CONCLUSIONS

Double-bundle ACL reconstruction can be used to achieve better anterior and rotational stability and has a lower rate of arthritic progression and tunnel expansion than the single-bundle procedure.

LEVEL OF EVIDENCE

I.

Review of evolution of tunnel position in anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) rupture is one of the commonest knee sport injuries. The annual incidence of the ACL injury is between 100000-200000 in the United States. Worldwide around 400000 ACL reconstructions are performed in a year. The goal of ACL reconstruction is to restore the normal knee anatomy and kinesiology. The tibial and femoral tunnel placements are of primordial importance in achieving this outcome. Other factors that influence successful reconstruction are types of grafts, surgical techniques and rehabilitation programmes. A comprehensive understanding of ACL anatomy has led to the development of newer techniques supplemented by more robust biological and mechanical concepts. In this review we are mainly focussing on the evolution of tunnel placement in ACL reconstruction, focusing on three main categories, i.e., anatomical, biological and clinical outcomes. The importance of tunnel placement in the success of ACL reconstruction is well researched. Definite clinical and functional data is lacking to establish the superiority of the single or double bundle reconstruction technique. While there is a trend towards the use of anteromedial portals for femoral tunnel placement, their clinical superiority over trans-tibial tunnels is yet to be established.

Anatomic anterior cruciate ligament reconstruction: a changing paradigm

Injury to the anterior cruciate ligament (ACL) of the knee is potentially devastating for the patient and can result in both acute and long-term clinical problems. Consequently, the ACL has always been and continues to be of great interest to orthopaedic scientists and clinicians worldwide. Major advancements in ACL surgery have been made in the past few years. ACL reconstruction has shifted from an open to arthroscopic procedure, in which a two- and later one-incision technique was applied. Studies have found that traditional, transtibial arthroscopic single-bundle reconstruction does not fully restore rotational stability of the knee joint, and as such, a more anatomic approach to ACL reconstruction has emerged. The goal of anatomic ACL reconstruction is to replicate the knee's normal anatomy and restore its normal kinematics, all while protecting long-term knee health. This manuscript describes the research that has changed the paradigm of ACL reconstruction from traditional techniques to present day anatomic and individualized concepts.

Revision single-bundle anterior cruciate ligament reconstruction with over-the-top route procedure

PURPOSE

In revision anterior cruciate ligament reconstruction (ACLR), the single-stage technique and the over-the-top route (OTTR) procedure were usually selected for cases where the bone tunnel cannot be created at an anatomical position due to tunnel enlargement and overlap with the mal-positioned tunnel of primary reconstruction. The purpose of this study was to evaluate the clinical results of revision single-bundle ACL reconstruction using OTTR procedure and to compare the clinical results of OTTR procedure with those of anatomical single-bundle revision reconstruction (SBR).

HYPOTHESIS

The results of OTTR procedure are equivalent to that of SBR.

METHODS

Seventy-six revision ACL reconstruction knees from April 2002 to December 2012 were involved in our study. We focused on 21 knees which underwent surgery with SBR and 22 knees with OTTR using hamstring tendon. The clinical results were evaluated by means of the Lysholm score and the knee stability was assessed by the Lachman test, pivot-shift test and side-to-side difference by KT-2000 pre-operatively and after 1 year post-operatively. AP translation and rotational laxity using a navigation system were evaluated before and after revision ACL reconstruction under anesthesia in 8 cases of OTTR and in 6 cases of SBR.

RESULTS

There was no statistically significant difference between the OTTR and SBR regarding Lysholm score, Lachman test, pivot-shift test, ATT by KT-2000, and AP translation and rotational laxity with a navigation system.

CONCLUSIONS

The clinical results of OTTR are almost equivalent to those of SBR. For the cases in which it is impossible to create the femoral tunnel in an anatomical position, OTTR is a valuable revision ACL reconstruction method.

LEVEL OF EVIDENCE

Case-control study. Level III.

Comparison of femoral tunnel geometry, using in vivo 3-dimensional computed tomography, during transportal and outside-in single-bundle anterior cruciate ligament reconstruction techniques

PURPOSE

To compare the transportal (TP) and outside-in (OI) techniques regarding femoral tunnel position and geometry after anatomic single-bundle (SB) anterior cruciate ligament (ACL) reconstruction.

METHODS

This study included 51 patients who underwent anatomic SB ACL reconstruction with the TP (n = 21) or OI (n = 30) technique. All patients underwent 3-dimensional computed tomography 3 days after the operation. The femoral tunnel position (quadrant method), femoral graft bending angle, femoral tunnel length, and posterior wall breakage were assessed by immediate postoperative 3-dimensional computed tomography with OsiriX imaging software.

RESULTS

The OI technique had a shallower femoral tunnel position (arthroscopic position) than did the TP technique (P = .005). The mean femoral graft bending angle was significantly more acute with the OI technique (101.3° ± 8.2°) than with the TP technique (107.9° ± 10.0°) (P = .02). The mean femoral tunnel length was significantly greater with the OI technique (33.0 ± 3.5 mm) than with the TP technique (29.6 ± 3.9 mm) (P = .003). Posterior wall breakage occurred in 7 cases (33.3%) with the TP technique and 1 case (3.3%) with the OI technique (P = .02).

CONCLUSIONS

The mean femoral tunnel position was significantly shallower (arthroscopic position) with the OI technique than with the TP technique. The OI technique resulted in a more acute femoral graft bending angle, longer femoral tunnel length, and lower incidence of posterior wall breakage than did the TP technique. These results might be helpful for anatomic SB ACL reconstruction using TP and OI techniques.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Trans-tibial guide wire placement for femoral tunnel in single bundle anterior cruciate ligament reconstruction

BACKGROUND

Femoral tunnel location is of critical importance for successful outcome of ACL reconstruction. The aim was to study the femoral tunnel created by placing free hand guide wire through tibial tunnel, using the toggle of the guide wire in the tibial tunnel to improve femoral tunnel location.

MATERIALS AND METHODS

30 cases of a single bundle quadrupled hamstring graft anterior cruciate ligament reconstruction by trans-tibial free hand femoral tunnel creation is studied in this prospective study. The side to side play of the guide wire in the tibial tunnel was used to improve the tunnel location on femoral wall. The coronal angle of the femoral tunnel was measured on the anteroposterior radiograph. The femoral tunnel location on the lateral radiograph of the knee was recorded according to Amis method. Lysholm scoring was done preoperative and at each follow up. Assessment of laxity was done by Rolimeter (Aircast(™)) and pivot shift test.

RESULTS

The mean coronal angle of the femoral tunnel in postoperative radiograph was 47°. In lateral radiograph, the femoral tunnel was found to be >60% posterior on Blumensaat line in 67% cases (n = 20) and in the 33% cases (n = 10) it was anterior. The mean Lysholm score improved from 74.6 preoperative to 93.17 postoperative with no objective evidence of laxity.

CONCLUSION

The free hand trans-tibial creation of the femoral tunnel leads to satisfactory coronal obliquity, but it is difficult to recreate anatomic femoral tunnel by this method as the tunnel is consistently anterior in the sagittal plane.

Comparison of the Modified Transtibial Technique, Anteromedial Portal Technique and Outside-in Technique in ACL Reconstruction

Purpose

To compare clinical and radiographic results of anterior cruciate ligament (ACL) reconstruction using modified transtibial technique (mTT), anteromedial (AM) portal technique and outside-in (OI) technique.

Materials and Methods

From March 2007 to December 2012, ACL reconstruction was performed using the mTT, AM portal technique and OI technique in 20 patients each. Anteroposterior and rotational stability were assessed using the GNRB arthrometer and pivot-shift test. Femoral tunnel obliquity was measured on the anteroposterior and lateral radiographs.

Results

Tegner score, Lysholm score, International Knee Documentation Committee score, pivot-shift test were improved at final follow-up in all three groups. However, statistical difference was not shown. Side-to-side difference in GNRB arthrometer was average of 1.4 mm, 1.0 mm and 0.9 mm in mTT, AM and OI group, showing the signicant difference between mTT and AM/OI groups (p<0.001). The mean femoral tunnel obliquity was 56.4° in the mTT group, 39.4° in the AM group and 33.6° in the OI group, showing significant intergroup difference (p<0.001). It showed the significant difference among three groups (p<0.001).

Conclusions

Clinical results were improved in all three groups. Femoral tunnel obliquity in AM and OI were more horizontal on the coronal plane. They are thought to have more benefits in oblique positioning of the grafted ACL in rotational stability; however, there was no significant difference among three techniques in pivot-shift test to assess the rotational stability in this study.

Creation of femoral tunnel by outside-in technique for ACL reconstruction: an analysis

PURPOSE

To study the outcome of ACL reconstruction by retrograde outside-in (OI) creation of femoral tunnel.

METHODS

ACL reconstruction was done in 41 cases by OI technique. The tip of 115° femoral guide was placed at posterior aspect of femoral foot print of ACL. Reaming was done from outside-in over guide pin. The length of femoral tunnel was obtained by measuring guide pin. The location of intra-articular femoral tunnel aperture and graft was recorded. Tibial tunnel was created with 50° guide placed at tibial foot print of ACL. Post-operative digital radiograph was taken. Antero-posterior view was used to calculate coronal inclination of femoral tunnel. On lateral view femoral tunnel location was marked in relation to the intersection of Blumensaat line and posterior femoral cortical line. Lysholm scoring and pivot shift test were performed at follow-up. Objective measurement of anterior tibial translation was done by rolimeter (aircast) at 1 year.

RESULTS

The mean femoral tunnel length recorded was 39.5 mm (±3.4). There was no incidence of femoral tunnel blow out or graft impingement. All cases had femoral tunnel aperture location posterior to posterior femoral cortical line and inferior to Blumensaat line. The mean coronal angle of femoral tunnel was 30.39° (±4.6). The mean preoperative Lysholm score of 53.5 (±13) increased to 95.2 (±3.5) 1 year after surgery. All the patients had full range of motion. The pivot shift test was negative and instrumented measurement of anterior translation of tibia was near normal in all cases.

CONCLUSION

OI technique of ACL reconstruction is a simple reproducible technique. The unconstrained placement and angling of femoral guide result in a femoral tunnel which is through footprint of ACL. The graft is placed very low, oblique and as posterior as possible on femoral side mimicking the native ACL.

LEVEL OF EVIDENCE

III.

The relation between knee flexion angle and anterior cruciate ligament femoral tunnel characteristics: a cadaveric study comparing a standard and a far anteromedial portal

PURPOSE

The purpose of this study was to compare the anterior cruciate ligament (ACL) femoral tunnel characteristics between 2 common arthroscopic portals used for ACL reconstruction, a standard anteromedial portal and a far anteromedial portal.

METHODS

Seven cadaveric knees were used. A 1.25-mm Kirschner wire was drilled through the center of the ACL femoral footprint and through the distal femur from the standard anteromedial and far anteromedial portals at knee flexion angles of 100°, 120°, and 140°. No formal tunnels were drilled. Each tunnel exit point was marked with a colored pin. After all tunnels were created, the specimens were digitized with a MicroScribe device (Revware, Raleigh, NC) to measure the tunnel length; distance to the posterior femoral cortical wall (posterior cortical margin); and tunnel orientation in the sagittal, coronal, and axial planes.

RESULTS

The standard anteromedial portal resulted in a longer tunnel length, a less horizontal tunnel in the coronal plane, and a greater posterior cortical margin compared with the far anteromedial portal at all knee flexion angles. For both portal locations, the tunnel length and posterior cortical margin increased, and the tunnel position became more horizontal in the coronal plane, more anterior in the sagittal plane, and less horizontal in the transverse plane as knee flexion increased.

CONCLUSIONS

Portal position affects femoral tunnel characteristics, with results favoring the more laterally positioned standard anteromedial portal at all flexion angles. Increasing the knee flexion angle leads to a longer femoral tunnel length and posterior femoral cortical margin with either portal position.

CLINICAL RELEVANCE

Understanding how portal positioning and knee flexion angle affect femoral tunnel orientation and characteristics may lead to improved surgical outcomes after ACL reconstruction.

Kinematic analysis of the indirect femoral insertion of the anterior cruciate ligament: implications for anatomic femoral tunnel placement

PURPOSE

To determine the effect of debriding the indirect insertion component of the femoral anterior cruciate ligament (ACL) attachment on tibiofemoral kinematics when compared with the intact knee.

METHODS

Knee kinematics were measured in 9 cadaveric knees with the ACL intact, after indirect insertion debridement, and after ACL transection. Three loading conditions were used: (1) a 134-N anterior tibial load, (2) a combined 10-Nm valgus and 5-Nm internal tibial torque, and (3) a simulated robotic pivot shift. Anterior tibial translation (ATT) was recorded in response to anterior and combined loads at 0°, 15°, 30°, 45°, 60°, and 90° of flexion. Posterior tibial translation and external tibial rotation were recorded during the simulated pivot shift.

RESULTS

With an anterior load, indirect insertion debridement increased ATT by 0.37 ± 0.24 mm at 0° (P = .002) and by 0.16 ± 0.19 mm at 15° (P = .033; increases <1 mm in all specimens). ACL transection increased ATT in response to an anterior load (P = .0001) with maximum effect at 15° compared with the intact and debrided states (11.26 ± 1.15 mm and 11.04 ± 1.08 mm, respectively). With a combined load, indirect insertion debridement increased ATT by 0.17 ± 0.11 mm at 0° (P = .001; increases <0.3 mm in all specimens) with no effect at other angles. ACL transection increased ATT in response to a combined load (P = .001) with maximum effect at 15° (4.45 ± 0.85 mm v ACL intact and 4.44 ± 0.84 mm v debrided indirect insertion). In the ACL intact condition, the pivot shift produced 1.29 ± 1.34 mm of posterior tibial translation and 1.54 ± 1.61° of external tibial rotation, as compared with 1.28 ± 1.34 mm and 1.54 ± 1.47°, respectively, after debridement (P = .68 and P = .99, respectively) and 12.79 ± 3.22 mm and 17.60 ± 4.30°, respectively, after ACL transection (P = .0001).

CONCLUSIONS

The indirect femoral ACL insertion contributes minimally to restraint of tibial translation and rotation.

CLINICAL RELEVANCE

Femoral tunnel positioning for anatomic ACL reconstruction should aim to recreate the biomechanically significant direct insertion.

Effect of anteromedial portal entrance drilling angle during anterior cruciate ligament reconstruction: a three-dimensional computer simulation

PURPOSE

The object of this study was to evaluate entrance angle effects on femoral tunnel length and cartilage damage during anteromedial portal drilling using three-dimensional computer simulation.

MATERIALS AND METHODS

Data was obtained from an anatomic study performed using 16 cadaveric knees. The anterior cruciate ligament femoral insertion was dissected and the knees were scanned by computer tomography. Tunnels with different of three-dimensional entrance angles were identified using a computer simulation. The effects of different entrance angles on the femoral tunnel length and medial femoral cartilage damage were evaluated. Specifically, tunnel length and distance from the medial femoral condyle to a virtual cylinder of the femoral tunnel were measured.

RESULTS

In tunnels drilled at a coronal angle of 45°, an axial angle of 45°, and a sagittal angle of 45°, the mean femoral tunnel length was 39.5±3.7 mm and the distance between the virtual cylinder of the femoral tunnel and the medial femoral condyle was 9.4±2.6 mm. The tunnel length at a coronal angle of 30°, an axial angle of 60°, and a sagittal angle of 45°, was 34.0±2.9 mm and the distance between the virtual cylinder of the tunnel and the medial femoral condyle was 0.7±1.3 mm, which was significantly shorter than the standard angle (p<0.001).

CONCLUSION

Extremely low and high entrance angles in both of axial plane and coronal plane produced inappropriate tunnel angles, lengths and higher incidence of cartilage damage. We recommend that angles in proximity to standard angles be chosen during femoral tunnel drilling through the anteromedial portal.

Variability of tunnel positioning in ACL reconstruction

INTRODUCTION

Since tunnel positioning is one of the key factors in anterior cruciate ligament (ACL) reconstruction and the variability of tunnel positioning in ACL reconstruction has so far never been analyzed, the objective of this study was to determine the inter- and intra-observer variability of tibial and femoral tunnel positioning in ACL reconstruction.

MATERIALS AND METHODS

In an operating room setup, 13 surgeons were asked to identify the tunnel positions in one and the same ACL-deficient cadaver knee. Using a fluoroscopic based ACL navigation system, tunnel positions were digitally measured in a test/re-test scenario. For variability analysis mean positions, standard deviations and range were calculated as well as differences between test/re-test positions.

RESULTS

The intraobserver analysis showed a tibial variability of 3.3 mm (SD 2.1, range 7.5 mm) and a femoral variability of 2.0 mm (SD 1.6 mm, range 6.8 mm). The interobserver variability of the tibial tunnel positions was 3.2 mm (SD) with a range of 18.3 mm and a femoral variability of 3.7 mm (SD) with a range of 13.2 mm.

CONCLUSIONS

This study demonstrates that a reasonable inter- and intra-observer variability in ACL tunnel positioning exists even among experienced surgeons. Although deviations of 2-3 mm may seem to be acceptable at first sight, a range of up to 18.3 mm indicates that outliers exist, which can cause graft failure. More reliable reconstruction techniques should be developed to reduce the variability in tunnel positioning.

Arthroscopic BPTB graft reconstruction in ACL ruptures: 15-year results and survival

PURPOSE

The aim of this study is to investigate the 15-year results and survival of arthroscopic ACL reconstruction using the central-third patellar bone-tendon-bone (BPTB) autograft.

METHODS

ACL BPTB reconstruction was performed in 250 consecutive patients. Of these patients, 88% returned for a follow-up examination at 15 years after reconstruction. Therefore, 220 patients were studied. Mean time from injury to intervention was 3.4months (range 2 to 16). The parameters for assessment of results were subjective satisfaction, clinical examination (pivot-shift test, Lachman test with KT-1000), recovery of pre-injury activity level, and long-leg standing radiographs. We also evaluated the presence of meniscal and/or chondral injuries during the procedure. Failure rates were also evaluated. We defined a failure as severe instability not compatible with the activities of daily living (ADL) due to graft rupture.

RESULTS

8.2% of patients required a revision procedure because of graft rupture. In subjective terms, 98.1% of patients said that they were satisfied with the surgical outcomes after 15 years. Pivot shift test was normal in 93.5% at 15 years. Lachman test (KT-1000) was normal in 95.4% at 15 years. Fifteen years after surgery, 90% of patients recovered their pre-injury activity level. In 25.4% of patients symptomatic osteoarthritic changes in the knee were found at 15 years.

CONCLUSIONS

The survival prevalence of arthroscopic ACL reconstruction using the central-third patellar bone-tendon-bone (BPTB) autograft at 15 years was 94.8%. Fifteen years after surgery, 90% of patients recovered their pre-injury activity level. In 25.4% of patients symptomatic osteoarthritic changes in the knee were found at 15 years.

LEVEL OF EVIDENCE

Level IV.

Is the clock face an accurate, precise, and reliable measuring tool for anterior cruciate ligament reconstruction?

PURPOSE

(1) To assess the use and practice of the clock face among surgeons who routinely perform anterior cruciate ligament (ACL) reconstructions, and (2) to assess the accuracy, precision, and reliability of 3 commonly used clock-face schemes in ACL reconstruction.

METHODS

First, 9 surgeons completed a questionnaire assessing the use and definition of the clock-face technique. Next, to assess the accuracy, precision, and reliability of the clock face, each surgeon estimated the "time" of 8 artificial femur models with a black dot located on the posterior aspect of the lateral condylar wall. The estimates were performed using 3 different clock-face schemes and were repeated 10 months later. Solutions for each specimen were obtained by use of a computer graphical interface.

RESULTS

More than half of the respondents (55%) use the clock face in ACL reconstructions, with the reported mean ideal "time" for a femoral tunnel in a right knee of 10:05 (SD, 31 minutes). When we accounted for the different clock definitions, this ideal position was found along the entire lateral condylar wall. In the assessment of the performance of the clock face, the mean error was 32 to 40 minutes (which translates to 3 to 4 mm) among the 3 clock schemes. The maximum error was 4 hours 0 minutes, and the range of responses was 1 hour 0 minutes to 4 hours 0 minutes depending on the specimen and clock scheme. Regardless of the clock scheme used, the intrarater and inter-rater reliabilities were similar-measuring, on average, 0.78 and 0.68, respectively.

CONCLUSIONS

The clock face continues to be commonly used in ACL reconstruction. Different clock-face definitions affect the position for the same "time." When the clock-face parameters were strictly defined, there was good reliability with borderline accuracy and poor precision.

CLINICAL RELEVANCE

Considering the borderline performance of the clock face in accuracy and poor precision, we recommend against using the clock face in ACL reconstruction.

Commonly used ACL autograft areas do not correlate with the size of the ACL footprint or the femoral condyle

PURPOSE

The purpose of this study was to reveal the correlation between the size of the native anterior cruciate ligament (ACL) footprint and the area of commonly used autografts using cadaveric knees.

METHODS

Twenty-Four non-paired human cadaver knees were used. The size of the femoral and tibial ACL footprints, length of Blumensaat's line, and the height and area of the lateral wall of the femoral intercondylar notch were photographed and measured with Image J software (National Institution of Health). Simulating an semitendinosus tendon (ST) graft, the ST was cut in half. The bigger half was regarded as the antero-medial (AM) bundle, and the remaining half was regarded as the postero-lateral (PL) bundle. Simulating an semitendinosus and gracilis (ST-G) graft, the bigger half of the ST and G was regarded as the AM bundle, and the smaller half of the ST was regarded as the PL bundle. Each graft diameter was measured, and the graft area was calculated. Simulating a bone-patella tendon-bone (BPTB) graft, a 10-mm wide BPTB graft was harvested and the area calculated.

RESULTS

The sizes of the native femoral and tibial ACL footprints were 72.3 ± 24.4 and 134.1 ± 32.4 mm(2), respectively. The length of Blumensaat's line, and the height and area of the lateral wall of the femoral intercondylar notch were 29.5 ± 2.5 mm, 17.7 ± 2.3 mm, and 400.9 ± 62.6 mm(2), respectively. The average areas of the ST, ST-G, and BPTB graft were 52.7 ± 6.3, 64.7 ± 7.6, and 37.1 ± 7.5 mm(2). Both the height and the area of the lateral wall of the femoral intercondylar notch were significantly correlated with the femoral size of the ACL footprint (p = 0.007 and 0.008, respectively). However, no significant correlation was observed between ACL footprint size and autograft size. No significant correlation was observed between autograft size and the size of the lateral wall of the femoral intercondylar notch.

CONCLUSION

In ACL reconstruction, if the reconstructed ACL size is determined by the harvested autograft size alone, native ACL size and anatomy are unlikely to be reproduced.

Arthrometric stability of horizontal versus vertical single-bundle arthroscopic anterior cruciate ligament reconstruction

The anteroposterior (AP) stability of standard anterior cruciate ligament (ACL) reconstruction, referred to as "vertical," was compared with that of a modified femoral position, referred to as "horizontal," which is lower than and anterior to an operative knee at 90° flexion. Two consecutive series of 50 patients underwent vertical and horizontal arthroscopic single-bundle ACL reconstruction, respectively. For vertical reconstruction, the clock position was chosen, placing the graft at 10:30 in right knees and 1:30 in left knees, 1 to 2 mm anterior to the posterior femoral cortical cortex and at the back of the resident ridge. In the horizontal reconstruction, the transplant replaced the original ligament insertion at approximately the 9:30 o'clock position in right knees and the 2:30 o'clock position in left knees, approximately 2 mm in front of the posterior femoral cortical cortex. One year after surgery, the results of stabilometric evaluation revealed good performance after horizontal transplant. The mean clinical results changed from 1.0 (±1.3) mm for vertical to 0.7 (±1.3) mm for horizontal reconstruction.

A comparison of dynamic rotational knee instability between anatomic single-bundle and over-the-top anterior cruciate ligament reconstruction using triaxial accelerometry

PURPOSE

Recently, single-bundle (SB) anterior cruciate ligament (ACL) reconstruction has been advanced by the anatomic concept, but the biomechanical outcome of the anatomic method has not been fully investigated, especially for rotational instability. Anatomic SB and the single over-the-top procedures are the treatment of choice for primary cases and revision or skeletally immature cases, respectively. The purpose of this study was to investigate the dynamic rotational instability of anatomic SB and over-the-top reconstruction during a pivot shift test using triaxial accelerometry.

METHODS

Eight fresh frozen human cadaveric knees were used in this study. Rotational instability measurement was conducted during a pivot shift test by the use of a triaxial accelerometer attached to the tibia. The tests were performed in the ACL-intact, ACL-deficient and ACL-reconstructed knees with two different procedures (anatomic SB and over-the-top). The acceleration in three directions and the magnitude of acceleration were measured to evaluate rotational instability and compare between four different knee states.

RESULTS

The overall magnitude of acceleration was significantly different (P < 0.01) between the ACL-intact knees and the ACL-deficient knees. Both anatomic SB and over-the-top ACL reconstruction significantly reduced the overall magnitude of acceleration compared to the ACL-deficient knees, but still had larger accelerations compared to the ACL-intact knees. There was no significant difference for the overall magnitude of acceleration between anatomic SB and over-the-top reconstruction procedure.

CONCLUSION

Over-the-top reconstruction provides comparable result to anatomic SB reconstruction in terms of controlling the dynamic rotational stability. Over-the-top reconstruction might be one of the options for revision cases and in skeletally immature patients.

Knee mechanics during landing in anterior cruciate ligament patients: A longitudinal study from pre- to 12 months post-reconstruction

BACKGROUND

Patients with a history of anterior cruciate ligament rupture are at elevated risk of developing knee osteoarthritis. Altered knee kinematics and kinetics during functional activities have been viewed as risk factors for cartilage breakdown and, therefore, one of the primary goals of anterior cruciate ligament reconstruction is to restore knee joint function.

METHODS

Patients' (n=18) knee mechanics while performing a single leg hop for distance were calculated for both legs using a soft-tissue artifact optimized rigid lower-body model at the pre-reconstruction state and six and twelve months after anterior cruciate ligament reconstruction.

FINDINGS

Independent of the analyzed time point the involved leg showed a lower external flexion and adduction moment at the knee, and an increased anterior translation and external rotational offset of the shank with respect to the thigh compared to the uninvolved leg. There were no differences for any of the analyzed knee kinematic and kinetic parameters within the control subject group.

INTERPRETATION

The identified kinematic changes can cause a shift in the normal load-bearing regions of the knee and may support the view that the risk of developing knee osteoarthritis in an anterior cruciate ligament ruptured joint while performing activities involving frequent landing and stopping actions is less likely to be associated with the knee adduction moment and is rather due to kinematic changes. Anterior cruciate ligament reconstruction surgery failed to restore normal knee kinematics during landing, potentially explaining the persistent risk for the development of knee osteoarthritis in patients who have returned to sports following reconstruction surgery.

Comparison of transtibial and transportal techniques in drilling femoral tunnels during anterior cruciate ligament reconstruction using 3D-CAD models

Purpose

The purpose of this study was to assess the differences in bone tunnel apertures between the trans-accessory medial portal (trans-AMP) technique and the transtibial (TT) technique in double-bundle anterior cruciate ligament reconstruction. The extent of ovalization and the frequency of overlap of the two tunnel apertures were compared.

Methods

The simulation of femoral tunnel drilling with the TT and the trans-AMP techniques was performed using three-dimensional computer aided design models from two volunteers. The incidence angle of drilling against the intercondylar wall, the femoral tunnel position, the ovalization, and the overlap were analyzed. The aperture and location of the tunnels were also examined in real anterior cruciate ligament reconstruction cases (n=36).

Results

The surgical simulation showed that a lower drill incident angle induced by the TT technique made the apertures of two tunnels more ovalized, located anteromedial tunnels in a shallower position to prevent posterior wall blow out, and led to a higher frequency of tunnel overlap. The trans-AMP group had tunnel places within the footprint and had less ovalization and overlap. The results of analysis for tunnels in the clinical cases were consistent with results from the surgical simulation.

Conclusion

In the TT technique, the shallow anteromedial tunnel location and more ovalized tunnel aperture can lead to a higher frequency of tunnel overlap. Compared with the TT technique, the trans-AMP technique was more useful in preparing femoral tunnels anatomically and avoiding tunnel ovalization and overlapping in double-bundle anterior cruciate ligament reconstruction.

Low inter- and intraobserver variability allows for reliable tunnel measurement in ACL reconstruction using the quadrant method

INTRODUCTION

Correct anatomic tunnel positions are essential in anterior cruciate ligament (ACL) reconstruction. To establish recommendations for tunnel positioning based on anatomical findings and to compare tunnel positions with clinical results, different radiological measurement methods as the quadrant method exist. Comparing the data of different observers requires the validation of the reliability of measurement methods. The purpose of this study therefore was to determine the reliability of the quadrant method to measure tunnel positions in ACL reconstruction. The hypothesis was, that the quadrant method shows a low inter- and intraobserver variability.

MATERIALS AND METHODS

In a test/retest scenario 20 knee surgeons were asked to determine defined tunnel positions in five lateral radiographs applying the quadrant method. Rotation, angle deviation, height and depth of the quadrant as well as absolute and relative tunnel positions of each observation were measured along referenced scales. Mean sizes and angle deviations of the quadrants, tunnel positions and deviations between the test/retest positions were calculated as well as standard deviations and range.

RESULTS

Interobserver variability analyses, to plan as well as to determine tunnel positions in ACL reconstruction, showed a mean variability (SD) of <1 mm, with ranges of 2.5 mm for planning and 3.7 mm for determination of tunnel positions using the quadrant method. Intraobserver analysis showed mean variability with deviations of <1 mm and maximum standard deviations of 0.7 mm and ranges of up to 2.3 mm.

CONCLUSIONS

We confirmed the hypothesis that the quadrant method has a low inter- and intraobserver variability. Based on the presented validation data, the quadrant method can be recommended as reliable method to radiographically describe insertion areas of the ACL as well as to determine tunnel positions in ACL reconstruction intra and postoperatively.

Biomechanical evaluation of the quadriceps tendon autograft for anterior cruciate ligament reconstruction: a cadaveric study

BACKGROUND

Recently, many surgeons have chosen the quadriceps tendon (QT) as an autograft for anterior cruciate ligament (ACL) reconstruction. However, there have not been biomechanical studies that quantitatively evaluated knee function after reconstruction using a QT autograft.

PURPOSE

To measure the 6 degrees of freedom knee kinematics and in situ graft forces after reconstruction with a QT autograft compared with a quadrupled semitendinosus and gracilis (QSTG) tendon autograft.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten human cadaveric knees (age, 54-64 years) were tested in 3 conditions: (1) intact, (2) ACL deficient, and (3) after ACL reconstruction using a QT or QSTG autograft. With use of a robotic/universal force-moment sensor testing system, knee kinematics and in situ forces in the ACL and autografts were obtained at 5 knee flexion angles under externally applied loads: (1) 134-N anterior tibial load, (2) 134-N anterior tibial load with 200-N axial compression, and (3) 10-N·m valgus and 5-N·m internal tibial torque.

RESULTS

Under the anterior tibial load, both autografts restored anterior tibial translation to within 2.5 mm of the intact knee and in situ forces to within 20 N of the intact ACL at 15°, 30°, and 60°. Adding compression did not change these findings. With the combined rotatory load, the anterior tibial translation and graft in situ forces were again not significantly different from the intact ACL. There were no significant differences between the grafts under any experimental condition.

CONCLUSION

Reconstruction of the ACL with a QT autograft restored knee function to similar levels as that reconstructed with a QSTG autograft under loads simulating clinical examinations.

CLINICAL RELEVANCE

The positive biomechanical results of this cadaveric study lend support to the use of a QT autograft for ACL reconstruction, as it could restore knee function immediately after surgery under applied loads that mimic clinical examinations.

The in vivo relationship between anterior neutral tibial position and loss of knee extension after transtibial ACL reconstruction

BACKGROUND

Restoration of anterior tibial stability while avoiding knee extension deficit are a common goal of anterior cruciate ligament (ACL) reconstruction. However, achieving this goal can be challenging. The purpose of this study was to determine whether side-to-side differences in anterior tibial neutral position and laxity are correlated with knee extension deficit in subjects 2 years after ACL reconstruction.

METHODS

In the reconstructed and contralateral knees of 29 subjects with transtibial reconstruction, anterior tibiofemoral neutral position was measured with MRI and three-dimensional modeling techniques; terminal knee extension at heel strike of walking and during a seated knee extension were measured via gait analysis; and anterior laxity was measured using the KT-1000.

RESULTS

Knees that approached normal anterior stability and anterior tibial position had increased extension deficit relative to the contralateral knee. On average the reconstructed knee had significantly less (2.1±4.4°) extension during active extension and during heel strike of walking (3.0±4.3º), with increased anterior neutral tibial position (2.5±1.7 mm) and anterior laxity (1.8±1.0 mm). There was a significant correlation between side-to-side difference in anterior neutral tibial position with both measures of knee extension (walking, r=-0.711, p<0.001); active knee extension, r=-0.544, p=0.002).

CONCLUSION

The results indicate a relationship between the loss of active knee extension and a change in anterior neutral tibial position following non-anatomic transtibial ACL reconstruction. Given the increasing evidence of a link between altered kinematics and premature osteoarthritis, these findings provide important information to improve our understanding of in vivo knee function after ACL reconstruction.

Evaluation of ACL mid-substance cross-sectional area for reconstructed autograft selection

PURPOSE

The purpose of this study was to compare the size of the native ACL mid-substance cross-sectional area and the size of commonly used autografts. Hypothesis of this study was that the reconstructed graft size with autografts would be smaller than the native ACL size.

METHODS

Twelve non-paired human cadaver knees were used. The ACL was carefully dissected, and the mid-substance of the ACL was cross-sectioned parallel to the articular surface of the femoral posterior condyles at 90 degrees of knee flexion. The size of the cross-sectional area of the ACL, and the femoral and tibial footprints were measured using Image J software (National Institute of Health). The semitendinosus tendon (ST) and the gracilis (G) tendon were harvested and prepared for ACL grafts. Simulating an ST graft, the ST was cut in half. The bigger half was regarded as the antero-medial (AM) bundle, and the remaining half was regarded as the postero-lateral (PL) bundle. Simulating an ST-G graft, the bigger half of the ST and G were regarded as the AM bundle, and the smaller half of the ST was regarded as the PL bundle. Each graft diameter was measured, and the graft area was calculated. Simulating a rectangular bone-patella tendon-bone (BPTB) graft, a 10-mm-wide BPTB graft was harvested and the area calculated.

RESULTS

The sizes of the ACL mid-substance cross-sectional area, femoral and tibial ACL footprint were 46.9 ± 18.3, 60.1 ± 16.9 and 123.5 ± 12.5 mm(2), respectively. The average areas of the ST, ST-G, and BPTB grafts were 52.0 ± 3.8, 64.4 ± 6.2, and 40.8 ± 6.7 mm(2), respectively. The ST and BPTB grafts showed no significant difference in graft size when compared with the ACL cross-sectional area.

CONCLUSION

ST and BPTB autografts were able to reproduce the native size of the ACL mid-substance cross-sectional area. The ST-G graft was significantly larger than the ACL cross-sectional area. For clinical relevance, ST and BPTB grafts are recommended in order to reproduce the native size of the ACL in anatomical ACL reconstruction with autograft.

Current concepts of the management of anterior cruciate ligament injuries in children

Recent reports have suggested an increase in the number of anterior cruciate ligament (ACL) injuries in children, although their true incidence is unknown. The prognosis of the ACL-deficient knee in young active individuals is poor because of secondary meniscal tears, persistent instability and early-onset osteoarthritis. The aim of surgical reconstruction is to provide stability while avoiding physeal injury. Techniques of reconstruction include transphyseal, extraphyseal or partial physeal sparing procedures. In this paper we review the management of ACL tears in skeletally immature patients.

Anatomic double-bundle anterior cruciate ligament reconstruction using in situ hamstring graft with 4 tunnels

A careful review of the literature suggests that a significant number of patients undergoing anterior cruciate ligament (ACL) reconstruction have less-than-optimal results. Although overall outcomes of ACL reconstruction are favorable, there remains considerable room for improvement. Anatomically, the ACL consists of 2 major functional bundles, the anteromedial bundle and the posterolateral bundle. Biomechanically, both bundles contribute significantly to the anterior and rotational stability of the knee. Therefore anatomic double-bundle ACL reconstruction techniques may further improve the outcomes in ACL surgery. This article presents a technique for arthroscopic double-bundle ACL reconstruction that includes the use of 2 femoral and 2 tibial tunnels to restore both the anteromedial and posterolateral bundles of the ACL with minimal hardware for fixation.

Single-bundle anterior cruciate ligament reconstruction: a biomechanical cadaveric study of a rectangular quadriceps and bone--patellar tendon--bone graft configuration versus a round hamstring graft

PURPOSE

The purposes of this study were to investigate anterior tibial translation under loading conditions after single-bundle (SB) anterior cruciate ligament (ACL) reconstruction using a rectangular tunnel placement strategy with quadriceps and bone--patellar tendon--bone (BPTB) graft and to compare these data with a SB hamstring reconstruction with a round tunnel design.

METHODS

In 9 human cadaveric knees, the knee kinematics were examined with robotic/universal force-moment sensor testing. Within the same specimen, the knee kinematics under simulated pivot-shift and KT-1000 arthrometer (MEDmetric, San Diego, CA) testing were determined at 0°, 15°, 30°, 60°, and 90° of flexion under different conditions: intact knee, ACL-deficient knee, and SB ACL-reconstructed knee. For the SB ACL-reconstructed knee, 3 different SB reconstruction techniques were used: a rectangular tunnel strategy (9 × 5 mm) with quadriceps graft, a rectangular tunnel strategy with BPTB graft, and a round tunnel strategy (7 mm) with hamstring graft.

RESULTS

In a simulated Lachman test, a statistically significant difference was found at 0° and 15° of knee flexion between the rectangular reconstruction with quadriceps graft (5.1 ± 1.2 mm and 8.3 ± 2 mm, respectively) or BPTB graft (5.3 ± 1.5 mm and 8 ± 1.9 mm, respectively) and the reconstruction using hamstring graft (7.2 ± 1.4 mm and 12 ± 1.8 mm, respectively) (P = .032 and P = .033, respectively, at 0°; P = .023 and P = .02, respectively, at 15°). On the simulated pivot-shift test at 0° and 15°, rectangular ACL reconstruction with quadriceps graft (3.9 ± 2.1 mm and 6.5 ± 1.7 mm, respectively) or BPTB graft (4.2 ± 1.8 mm and 6.7 ± 1.7 mm, respectively) showed a significantly lower anterior tibial translation when compared with round tunnel reconstruction (5.5 ± 2.1 mm and 7.9 ± 1.9 mm, respectively) (P = .03 and P = .041, respectively, at 0°; P = .042 and P = .046, respectively, at 15°).

CONCLUSIONS

Under simulated Lachman testing and pivot-shift testing, a reconstruction technique using a rectangular tunnel results in significantly lower anterior tibial translation at 0° and 15° of flexion in comparison to knees reconstructed with a hamstring SB graft using a round tunnel strategy.

CLINICAL RELEVANCE

ACL reconstruction with a rectangular tunnel and BPTB and quadriceps tendon might result in better anterior knee stability at low flexion angles than ACL reconstruction with hamstring SB graft and a round tunnel in the clinical setting.

Transtibial ACL femoral tunnel preparation increases odds of repeat ipsilateral knee surgery

BACKGROUND

Recent efforts to improve the results of anterior cruciate ligament (ACL) reconstruction have focused on placing the femoral tunnel anatomically. Medial portal femoral tunnel techniques facilitate drilling of femoral tunnels that are more anatomic than those made with transtibial techniques. Few studies have compared the clinical outcomes of these two femoral tunnel techniques. We hypothesized that the transtibial technique is associated with decreased Knee injury and Osteoarthritis Outcome Scores (KOOS) and an increased risk of repeat surgery in the ipsilateral knee when compared with the anteromedial portal technique.

METHODS

Four hundred and thirty-six patients who had undergone primary isolated autograft ACL reconstruction with a transtibial (229 patients) or anteromedial portal (207 patients) technique in 2002 or 2003 were identified in a prospective multicenter cohort. A multiple linear regression model was used to determine whether surgical technique (transtibial or anteromedial portal) was a significant predictor of KOOS at six years postoperatively, after controlling for preoperative KOOS, patient age, sex, activity level, body mass index (BMI), smoking status, graft type, and the presence of meniscal and chondral pathology at the time of reconstruction. A multiple logistic regression model was used to determine whether surgical technique was a significant predictor of repeat ipsilateral knee surgery, after controlling for patient age and activity level, graft type, and meniscal pathology at the time of reconstruction.

RESULTS

Postoperative KOOS were available for 387 patients (88.8%). Femoral tunnel drilling technique was not a predictor of the KOOS Quality of Life subscore (p = 0.72) or KOOS Function, Sports and Recreational Activities subscore (p = 0.36) at the six-year follow-up evaluation. Data regarding the prevalence of repeat surgery were available for 380 patients. Femoral tunnel technique was a significant predictor of subsequent ipsilateral knee surgery (odds ratio [OR] = 2.49, 95% confidence interval [CI] = 1.30 to 4.78, p = 0.006).

CONCLUSIONS

Patients who underwent ACL reconstruction with a transtibial technique had significantly higher odds of undergoing repeat ipsilateral knee surgery relative to those who underwent reconstruction with an anteromedial portal technique.

Physeal-sparing technique for femoral tunnel drilling in pediatric anterior cruciate ligament reconstruction using a posteromedial portal

Pediatric anterior cruciate ligament (ACL) tears present a technical dilemma for orthopaedic surgeons. Multiple surgical techniques have been described to protect the distal femoral and proximal tibial physes. We present an ACL reconstruction technique performed on a 12-year-old girl with open physes who sustained an ACL tear after a noncontact twisting injury while playing soccer. A hamstring autograft reconstruction was performed by use of a posteromedial portal to drill the femoral tunnel in an all-epiphyseal fashion at the anatomic footprint of the native ACL. This case provides a new surgical technique to achieve anatomic fixation for ACL reconstruction in a skeletally immature individual using a posteromedial portal to drill a physeal-sparing lateral femoral tunnel for anatomic ACL reconstruction. This advancement may make drilling the femoral tunnel less technically challenging compared with other proposed methods while maintaining the lateral wall of the distal femur.

Radiological evaluation for conflict of the femoral tunnel entrance area prior to anterior cruciate ligament revision surgery

PURPOSE

Anterior cruciate ligament (ACL) revision surgery is a demanding procedure and requires meticulous pre-operative clinical and radiological assessment. In clinical practice the position of the femoral tunnel is identified mainly using plain radiographs (XR). Two-dimensional computed tomography (2D-CT) and magnetic resonance imaging (MRI) are not yet routine imaging methods and are only performed in specific clinical indications or in the scientific setting. Several measurement methods describe the femoral tunnel after ACL reconstruction and indicate 'ideal or wrong' placement to the surgeon. The aim of this study is to provide a reliable measurement method to predict potential conflict between the pre-existing and the planned femoral tunnel entrance area (FTEA).

METHODS

Ten patients with primary ACL reconstruction served as a reference group to describe our desired FTEA. Their femoral tunnel positioning was measured on XR and 2D-CT according to published measurement methods. These results were compared to the FTEA measured with a new technique on 3-dimensionally reconstructed CT-images (3D-CT) based on intra-operative landmarks. Twenty patients requiring ACL revision surgery underwent identical radiological examination. The mean values of the reference group were compared to each measurement of the patients requiring revision surgery.

RESULTS

3D-CT measurements found potential conflicts in nine out of 20 patients, which all proved to be true during arthroscopic revision surgery. Only one of these patients was identified in all XR and 2D-CT measurements. In 12 out of all 30 patients some measurements on XR or 2D-CT could not be recorded.

CONCLUSION

3D-CT reconstruction shows the most accuracy in depicting conflict of the pre-existing and desired femoral tunnel prior to ACL revision surgery. The desired FTEA must be defined for each surgeon and his individual technique. In contrast, precision of conventional measurement techniques on XR and 2D-CT is low and does not qualify for this purpose.

Coverage of the anterior cruciate ligament femoral footprint using 3 different approaches in single-bundle reconstruction: a cadaveric study analyzed by 3-dimensional computed tomography

BACKGROUND

Performing a single-bundle anterior cruciate ligament (ACL) reconstruction within the femoral footprint is important to obtain a functional graft and a stable knee.

HYPOTHESIS

There will be a significant difference in the ability of 3 ACL reconstruction techniques to reach and cover the native femoral footprint.

STUDY DESIGN

Controlled laboratory study.

METHODS

The percentage of the ACL footprint covered by the femoral tunnel was compared after 3 different techniques to target the footprint: transtibial (TT), inside-out/anteromedial (IO), and outside-in/transfemoral (OI). Fourteen cadaveric knee specimens with a mean age of 67.5 years were used. For each knee, the TT technique utilized a 7.5-mm offset guide, the IO technique was performed through an accessory anteromedial portal, and the OI technique was carried out through the femur from the external wall of the lateral condyle. Entry points in the footprint were spotted with markers, and orientations (sagittal and frontal) of each drill guide were noted. The distal femurs were sawed and scanned, and 3-dimensional image reconstructions were analyzed. The virtual drilled area (reamer diameter, 8 mm) depending on the entry point and the sagittal/frontal orientation of the drill guide was calculated and reported for each of the 3 techniques. The distance from the tunnel center to the ACL center, percentage of the femoral tunnel within the ACL footprint, and percentage of the ACL footprint covered by the tunnel were calculated and statistically compared (analysis of variance and t test).

RESULTS

The average distance to the native femoral footprint center was 6.8 ± 2.68 mm for the TT, 2.84 ± 1.26 mm for the IO, and 2.56 ± 1.39 mm for the OI techniques. Average percentages of the femoral tunnel within the ACL footprint were 32%, 76%, and 78%, and average percentages of the ACL footprint covered by the tunnel were 35%, 54%, and 47%, for the TT, IO, and OI techniques, respectively. No significant difference was observed between the IO and OI techniques (P = .11). The TT approach gave less satisfactory coverage on all testing criteria.

CONCLUSION

The IO and OI techniques allowed for creation of a tunnel closest to the ACL femoral footprint center. Despite this fact and even if the average percentage of the drilled area included in the femoral footprint was close to 80% for these 2 techniques, the average percentage of the ACL footprint covered by the tunnels was <55% for all 3 techniques. Coverage of the ACL footprint depended on the entry point, orientation, and diameter of the drilling but also on the size of the footprint.

CLINICAL RELEVANCE

To improve the coverage of the native femoral footprint with a single-bundle graft, in addition to the entry point it may also be necessary to consider the orientation of the drilling to increase the dimensions of the area while respecting the anatomic constraints of the femoral bone and graft geometry.