Intraoperative evaluation of the anatomical double-bundle anterior cruciate ligament reconstruction with the OrthoPilot navigation system

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.

A comparison of stability and clinical outcomes in single-radius versus multi-radius femoral design for total knee arthroplasty

We compared the intraoperative varus-valgus stability from 0° to 90° of flexion and postoperative clinical outcomes in patients receiving TKA via either a single-radius femoral design (50 TKA, SR group) or multi-radius femoral design (50 TKA, MR group). We measured stabilities at 0°, 30°, 60° and 90° of flexion using a navigation system. The clinical outcomes including HSS scores, WOMAC scores and VAS score during stair climbing were compared after a minimum of 2-year follow-up. The single-radius femoral designs in TKA showed better intra-operative stability at 30° of flexion (7.6 vs. 8.3) compared with the multi-radius femoral design, but not at other angles. However, the clinical outcomes revealed no other significant differences in terms of HSS scores, WOMAC scores and VAS score between two groups.

Extra-articular ACL Reconstruction and Pivot Shift: In Vivo Dynamic Evaluation With Navigation

BACKGROUND

The pivot-shift test is considered a reliable examination to evaluate the results of anterior cruciate ligament (ACL) reconstruction, as it strongly correlates with patient satisfaction, giving-way episodes, and activity level. The addition of lateral tenodesis (LT) to current techniques of intra-articular reconstruction with a hamstring graft could potentially improve knee laxity in cases of severe rotational instability.

PURPOSE

To biomechanically investigate the effect of intra- and extra-articular ACL reconstructions on knee laxity and the pivot-shift phenomenon.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty patients underwent anatomic single-bundle ACL reconstruction with doubled semitendinosus and gracilis tendons with the addition of extra-articular reconstruction. In patients in group A, intra-articular reconstruction was performed first and LT thereafter; in patients in group B, LT was performed first and intra-articular reconstruction thereafter. A navigator equipped with software designed for both static and dynamic evaluations was used to measure maximum anterior tibial translation (ATT) and axial tibial rotation (ATR) at 30° of flexion (static evaluation) and during the pivot-shift test (dynamic evaluation). Measurements were performed before reconstruction, after the first procedure, and after the second procedure.

RESULTS

For the static evaluation, in group A, the mean ATT significantly decreased from 14.1 ± 3.7 mm in the preoperative (ACL-deficient) condition to 6.0 ± 1.9 mm after ACL reconstruction and to 5.3 ± 1.6 mm after LT. The mean ATR at 30° of knee flexion significantly decreased from 35.7° ± 4.8° to 28.9° ± 4.1° and to 20.9° ± 4.8°, respectively. In group B, the mean ATT significantly decreased from 13.5 ± 6.5 mm in the preoperative (ACL-deficient) condition to 10.2 ± 3.2 mm after LT and to 4.0 ± 1.6 mm after ACL reconstruction. The mean ATR at 30° of knee flexion significantly decreased from 36.7° ± 4.8° to 26.2° ± 6.2° and to 23.5° ± 4.9°, respectively. For the dynamic evaluation (pivot-shift test), in group A, the mean ATT significantly decreased from 15.0 ± 6.8 mm in the preoperative (ACL-deficient) condition to 9.4 ± 6.4 mm after ACL reconstruction and to 8.5 ± 5.4 mm after LT. The mean ATR significantly decreased from 16.9° ± 4.7° to 11.6° ± 4.1° and to 6.1° ± 2.2°, respectively. In group B, the mean ATT significantly decreased from 12.5 ± 3.3 mm in the preoperative (ACL-deficient) condition to 9.1 ± 5.9 mm after LT and to 8.1 ± 5.4 mm after ACL reconstruction. The mean ATR significantly decreased from 16.0° ± 4.5° to 9.2° ± 4.3° and to 7.5° ± 4.0°, respectively.

CONCLUSION/CLINICAL RELEVANCE

Extra-articular reconstruction had little effect in reducing the anterior displacement of the tibia at 30° of flexion, but it was more effective than intra-articular reconstruction in reducing ATR. Anatomic ACL reconstruction and LT were synergic in controlling the pivot-shift phenomenon.

Roles of ACL remnants in knee stability

PURPOSE

This study evaluated knee laxity in anterior tibial translation and rotation following removal of anterior cruciate ligament (ACL) remnants using a computer navigation system.

METHODS

This prospective study included 50 knees undergoing primary ACL reconstruction using a navigation system. ACL remnants were classified into four morphologic types: Type 1, bridging between the roof of the intercondylar notch and tibia; Type 2, bridging between the posterior cruciate ligament and tibia; Type 3, bridging between the anatomical insertions of the ACL on the lateral wall of the femoral condyle and the tibia; and Type 4, no bridging of ACL remnants. Anterior tibial translation and rotatory laxity were measured before and after remnant resection using a navigation system at 30°, 60°, and 90° of knee flexion. The amount of change in anterior tibial translation and rotatory laxity of each type was compared among the types.

RESULTS

The different morphologic types of ACL remnants were as follows: Type 1, 15 knees; Type 2, 9 knees; Type 3, 6 knees; and Type 4, 20 knees. The amount of change in anterior tibial translation and rotatory laxity at 30° knee flexion in Type 3 was significantly larger than in the other types. There were no significant differences in either tibial translation or rotatory laxity at 60° and 90° knee flexion among the types.

CONCLUSIONS

In Type 3, ACL remnants contributed to anteroposterior and rotatory knee laxity evaluated at 30° knee flexion. The bridging point of the remnants is important to knee laxity. The Type 3 remnant should be preserved as much as possible when ACL reconstruction surgery is performed.

LEVEL OF EVIDENCE

Prognostic study, level II.

Knee rotation in healthy individuals related to age and gender

An external device ("the Rottometer") was especially designed to measure passive knee rotation in vivo. The device had earlier been evaluated with respect to it's validity and reliability. In the present study, we evaluated knee rotation in knee-healthy individuals and studied possible age and gender related differences. Measurements of total internal-external rotation were made at 90°, 60°, and 30° of flexion using 6 and 9 N m torques, as well as the examiner's apprehension of end-feel as displacing forces. The study group constituted of 120 healthy subjects (60 females and 60 males) with no prior or present knee disorders. The sample was divided into four age groups (15-30, 31-45, 46-60, and >60 years). The results showed no differences in knee rotation between the right and left knees or between the different flexion angles. The females showed 10-20% (p < 0.01) larger knee rotation than the males at all the three flexion angles and at all the three applied torques in all age-matched groups. In all age groups in both genders, the internal rotation accounted for 40-44% and the external for 56-60% of the total internal-external knee rotation.

Biomechanical techniques to evaluate tibial rotation. A systematic review

PURPOSE

This article systematically reviewed the biomechanical techniques to quantify tibial rotation, for an overview of how to choose a suitable technique for specific clinical application.

METHODS

A systematic search was conducted and finally 110 articles were included in this study. The articles were categorized by the conditions of how the knee was examined: external load application, physical examination and dynamic task.

RESULTS

The results showed that two-thirds of the included studies measured tibial rotation under external load application, of which over 80% of the experiments employed a cadaveric model. The common techniques used included direct displacement measurement, motion sensor, optical tracking system and universal force moment sensor. Intra-operative navigation system was used to document tibial rotation when the knee was examined by clinical tests. For dynamic assessment of knee rotational stability, motion analysis with skin reflective markers was frequently used although this technique is less accurate due to the skin movement when compared with radiographic measurement.

CONCLUSION

This study reports various biomechanical measurement techniques to quantify tibial rotation in the literatures. To choose a suitable measurement technique for a specific clinical application, it is suggested to quantify the effectiveness of a new designed surgical technique by using a cadaveric model before applying to living human subjects for intra-operative evaluation or long-time functional stability assessment. Attention should also be paid on the study's purpose, whether to employ a cadaveric model and the way of stress applied to the knee.

LEVEL OF EVIDENCE

IV.

Navigated knee kinematics after cutting of the ACL and its secondary restraint

PURPOSE

The purpose of this study is to evaluate the kinematics changes of the knee after cutting of the ACL with or without injury of the anterolateral structures.

METHODS

In this study, the role of the ACL and one of the secondary restraints in controlling knee stability using a navigation system was evaluated. The kinematics of the knee was evaluated in different conditions of instability: ACL intact, after dissection of the posterolateral (PL) bundle, after dissection of the anteromedial (AM) bundle, and after lesion of the lateral capsular ligament (LCL). Anterior tibial translation and rotation were measured with a computer navigation system in 10 fresh-frozen cadaveric knees by use of a manual maximum load. Anterior translation was evaluated at 30°, 60°, and 90° of flexion; rotation at 0°, 15°, 30°, 45°, 60°, and 90°.

RESULTS

Cutting the PL bundle does not increase anterior translation and rotation of the knee. Cutting the AM bundle significantly increased the anteroposterior (AP) translation at 30° and 60° (P = 0.01), but does not increase rotation of the knee. Cutting the LCL increased anterior translation at 60° (P = 0.04) and rotation at 30°, 45°, and 60° (P = 0.03).

CONCLUSIONS

Within the testing conditions of this study, the PL bundle does not affect anterior translation and rotation of the knee; the AM bundle is the primary restraint of the anterior translation but does not affect rotation of the knee while the lesion of the LCL increases tibial rotation and could be related to the pivot shift phenomenon, so it is more correct and biomechanical valid to assess and repair the associated lesion of the antero-lateral structure of the knee at the time of ACL surgery.

The relationship of anterior and rotatory laxity between surgical navigation and clinical outcome after ACL reconstruction

PURPOSE

Recently, a computer-assisted navigation system has been used for the quantitative evaluation not only of anterior-posterior (AP) laxity but also rotational laxity of the tibia intraoperatively. The purpose of this study was to investigate how intraoperative AP or rotational laxities measured by the navigation system could correlate with postoperative AP and rotational laxities of the patients.

METHODS

125 patients who underwent primary isolated anatomical single- or double-bundle ACL reconstruction or augmentation using multistranded autologous hamstring tendons were included in the study after a minimum of 2-year follow-up. Clinically, absolute value and side-to-side difference (SSD) of AP translation of the tibia were measured by KT-2000 preoperatively and postoperatively. Intraoperative measurement of AP translation of the tibia and total range of tibial rotation of the ACL-injured knee were carried out using the computer-assisted navigation system. We have investigated the relationship between intraoperative measurements using the navigation system and AP laxity measurements using the KT-2000 knee arthrometer as well as rotational laxity measurements using the manual pivot shift test.

RESULTS

There was a positive correlation between the SSD of preoperative AP translation of the tibia measured by KT-2000 arthrometer and the reduction in AP laxity following ACL reconstruction measured by the navigation system. However, we found no significant correlation between the reduction in AP laxity measured by the navigation system and the SSD of AP translation of the tibia measured by the KT-2000 arthrometer at final follow-up. Postoperatively, eight patients had a positive pivot shift test. Using the navigation system pre- and post-ACL reconstruction, these patients could not be identified by high absolute values for AP laxity nor rotational laxity.

CONCLUSION

Although AP and rotational laxities vary largely among the patients, and AP and rotational stabilization are successfully achieved immediately after ACL reconstruction, intraoperative AP and rotational laxity measured by the navigation system did not influence the postoperative AP and rotational laxities after ACL reconstruction.

LEVEL OF EVIDENCE

III.

Comparison of anterior and rotatory laxity using navigation between single- and double-bundle ACL reconstruction: prospective randomized trial

PURPOSE

To prospectively assess the anterior tibial translation and rotational kinematics of the knee joint as well as the clinical outcome after single-bundle (SB) and double-bundle (DB) anterior cruciate ligament (ACL) reconstruction.

METHODS

Forty-two patients randomly underwent single-bundle (Group SB, n = 21) or double-bundle (Group DB, n = 21) ACL reconstruction using hamstring tendon autografts. Anterior tibial translation and rotatory laxity were measured prior to and after fixation of the graft during reconstruction under the guidance of a navigation system. Clinical outcome measurements included the evaluation of the joint stability and functional status.

RESULTS

Anterior tibial translation and rotatory laxity were improved significantly at all degrees of knee flexion in both groups. The postoperative total rotation (sum of internal and external rotation) at 30° and 60° (26.6° vs. 24.0°; 28.7° vs. 25.1°) as well as postoperative change in external rotation at 60° (-1.4° vs. -4.6°), and a change in total rotation at 30° and 60° (-7.0° vs. -11.5°; -6.1° vs. -8.9°) differed between the two groups, with better stability in the DB group. At 2 years follow-up, IKDC subjective satisfaction score was significantly different between two groups (70.9 vs. 79.6), while manual and instrumented laxity, pivot shift tests, modified Lysholm score, Tegner activity score, thigh muscle strengths were not different. Correlation analysis showed little correlations between anterior laxity tests at follow-up, and the kinematic variables measured by navigation during surgery while pivot shift test, IKDC subjective satisfaction score, modified Lysholm score, and Tegner activity score were mainly correlated with navigation-measured rotations in both groups.

CONCLUSIONS

The kinematic tests in this study found evidence suggesting that the DB ACL reconstruction improved rotatory laxity better than the SB ACL reconstruction at 30° and 60° of flexion, but there was no difference in functional outcome at 2 years follow-up between SB and DB groups.

LEVEL OF EVIDENCE

Prospective comparative study, Level II.

Rotatory knee laxity tests and the pivot shift as tools for ACL treatment algorithm

The goal of anterior cruciate ligament (ACL) reconstruction surgery is to eliminate the pivot shift phenomenon. Different injury mechanisms and injury patterns may lead to specific knee laxity patterns. Computer navigation is helpful for the surgeon during examination under anesthesia. Surgical treatment may have to be altered if high-grade laxity is detected preoperatively for example by utilizing a computer navigation that is a helpful adjunct for surgeons during examination under anesthesia. A typical case for revision ACL reconstruction is presented. This article describes several techniques of laxity assessments. Based on the type and degree of pathologic laxity, a treatment algorithm has been developed.

LEVEL OF EVIDENCE

V.

Arthroscopic ACL reconstruction with reverse "Y"-plasty grafts and fixation in the femur with either a bioabsorbable interference screw or an Endobutton

We propose a new reverse "Y"-plasty graft for use in anterior cruciate ligament (ACL) reconstruction that involves double tibial tunnels and a single femoral tunnel. With this technique, the hamstrings were used as autografts and fixed separately with bioabsorbable interference screws (group A) or Endobuttons (group B) in femurs. A prospective series of 63 patients underwent primary reconstruction of the ACL; all procedures were performed by the same surgeon. Group A included 35 patients (22 male, 13 female), with a mean age of 25.5 (17-40) years, who were followed up for 28.5 (12-48) months. Group B included 28 patients (17 male, 11 female), with a mean age of 24.3 (18-38) years, who were followed up for 29.5 (12-46) months. Lysholm, International Knee Documentation Committee (IKDC) and Larson scoring were used to compare the therapeutic effects experienced at the knee. Lysholm scores were 93.26±2.67 (group A) and 93.81±2.42 (group B); Larson scores were 91.91±2.29 (group A) and 92.81±2.39 (group B); IKDC scores were 93.89±1.88 (group A) and 94.15±1.77 (group B). None of the scoring differences between groups were statistically significant (T(1)=0.849, P(1)=0.399, T(2)=1.506, P(2)=0.137, T(3)=0.560, P(3)=0.578). The Lachman test was negative in 46 patients (90.2%) and 51 knees, including 25 (89.3%) of the 28 knees in group A and 21 (91.3%) of the 23 knees in group B. Negative Pivot shift was present postoperatively in 49 knees of 51 patients (96.1%), including 27 (96.4%) of the 28 knees in group A and 22 (95.7%) of the 23 knees in group B. All of the patients in both groups achieved full extension and at least 135° of knee flexion. This novel technique involves the creation of double tibial tunnels and a single femoral tunnel. In the tibia, there was a bone bridge, ranging from 2 to 3mm, between the two bundles, which are tensioned at different degrees of flexion to maintain the stability of the knee. In the femur, the grafts were fixed with bioabsorbable interference screws or Endobuttons. The outcomes show that normal function and joint stability were achieved in both groups, as compared with preoperative measurements. Although the outcomes in group A (grafts fixed with the bioabsorbable interference screws in the femur) was better than those observed in group B (grafts fixed with Endobuttons), there was no statistical difference between the groups.

Prospective randomized clinical evaluation of conventional single-bundle, anatomic single-bundle, and anatomic double-bundle anterior cruciate ligament reconstruction: 281 cases with 3- to 5-year follow-up

BACKGROUND

Three different techniques of anterior cruciate ligament (ACL) reconstruction--conventional (transtibial) single bundle (CSB), anatomic single bundle (ASB), and anatomic double bundle (ADB)--have been described.

PURPOSE

To determine if double-bundle reconstruction is needed to restore rotational stability or if anatomic placement of a single bundle can yield similar results.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

From December 2005 to December 2007, 320 patients were prospectively randomized into 3 groups: ADB, ASB, and CSB reconstruction. The average follow-up was 51.15 months (range, 39-63 months). At the final follow-up, 281 patients were available. In all groups, hamstring tendons were used with suspensory fixation on the femoral side and bioabsorbable interference screw fixation on the tibial side. The outcomes were evaluated by an independent blinded observer using the Lysholm score and subjective International Knee Documentation Committee (IKDC) form. The KT-1000 arthrometer was used to evaluate anteroposterior stability, and the pivot-shift test was used to determine rotational stability.

RESULTS

Anatomic single-bundle reconstruction resulted in better anteroposterior and rotational stability than CSB reconstruction (average side-to-side difference for anterior tibial translation was 1.6 mm in the ASB group vs 2.0 mm in the CSB group; P = .002). Negative pivot shift was 66.7% vs 41.7% (P = .003). In other parameters, the differences between groups were not statistically significant. The results of the ADB group were also superior to the ASB group for anteroposterior and rotational stability (average side-to-side difference for anterior tibial translation was 1.2 mm in the ADB group vs 1.6 mm in the ASB group; P = .002). Negative pivot shift was 93.1% vs 66.7%, respectively (P < .001), and range of motion was also significantly different (P = .005). The Lysholm score was 90.9, 91.8, and 93.0 in the CSB, ASB, and ADB groups, respectively. The difference was significant only when we compared ADB and CSB (P = .025). Subjective IKDC scores were 90.2, 90.6, and 92.1 in the CSB, ASB, and ADB groups, respectively. The difference was not significant.

CONCLUSION

Anatomic double-bundle ACL reconstruction is significantly superior to conventional single-bundle ACL reconstruction and better than anatomic single-bundle reconstruction. Anatomic single-bundle reconstruction was superior to conventional single-bundle reconstruction. However, these differences are small and may not be clinically relevant.

The effect of graft fixation angles on anteroposterior and rotational knee laxity in double-bundle anterior cruciate ligament reconstruction: evaluation using computerized navigation

BACKGROUND

One of the main differences affecting outcome between single-bundle and double-bundle anterior cruciate ligament (ACL) reconstructions may be graft fixation angles and initial force settings; however, there has been little research to investigate these effects in either technique.

HYPOTHESIS

Anteroposterior and rotational knee laxities will be less in double-bundle ACL reconstructions than single-bundle reconstructions, and different graft fixation angles affect knee kinematics and pivot-shift phenomenon in double-bundle ACL reconstructions.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eleven patients who underwent double-bundle ACL reconstruction were included in this study. The anteromedial bundle (AMB) and the posterolateral bundle (PLB) were provisionally fixed to a graft tensioning system during surgery. The graft fixation settings were as follows: (1) AMB only at 20° (A20), (2) PLB only at 20° (P20), (3) AMB at 20° and PLB at 0° (A20P0), (4) AMB at 20° and PLB at 20° (A20P20), and (5) AMB at 20° and PLB at 45° (A20P45). All the grafts were tensioned at a constant stress level. Anterior tibial translation (ATT), internal rotation (IR), and external rotation (ER) at 30° and 90° of knee flexion applied with manual maximum load were measured before graft insertion and in each setting using a navigation system. A pivot-shift test was also evaluated manually with modified International Knee Documentation Committee criteria in each setting.

RESULTS

A20 was less constrained than A20P20 and A20P45 in ATT at 30° and less constrained than A20P45 in IR at 30°. P20 was less constrained than any other settings in ATT at 30° and less constrained than A20P45 in IR at 30°. A20P0 was less constrained than A20P45 in IR at 30° and in ER at 30°. Grade 1 pivot-shift phenomenon persisted in 8 cases in P20, in 4 cases in A20, and in 3 cases in A20P0, whereas no case showed a positive pivot-shift result in A20P20 and A20P45.

CONCLUSION

In this in vivo laboratory model, double-bundle ACL reconstruction with fixation of AMB at 20° and PLB at 20° or 45° restored better stability than single AMB or single PLB reconstruction in which the graft was of smaller size.

CLINICAL RELEVANCE

In double-bundle ACL reconstruction, fixation of the PLB at 0° might be looser and function worse compared with that of PLB at 20° or 45° when the AMB is fixed at 20°, with the individual variability that should lead to caution until it can be better assessed by surgeons.

Prospective evaluation of patients with anterior cruciate ligament reconstruction using a patient-based health-related survey: comparison of single-bundle and anatomical double-bundle techniques

PURPOSE

To compare the treatment outcomes of single-bundle and anatomical double-bundle anterior cruciate ligament (ACL) reconstructions, we used the patient-based health-related QOL questionnaire SF-36 to evaluate patients with ACL injury who underwent surgical reconstruction using the two techniques.

PATIENTS AND METHODS

A prospective study was performed on patients who were diagnosed with ACL injury and underwent ACL reconstruction. Eighty-four male patients who were followed for at least 2 years were analyzed in this study. Forty-four patients were operated by single-bundle technique, and 40 by double-bundle technique. SF-36, Lysholm score, anterior tibial translation, and pivot shift were assessed before surgery and 6, 12 and 24 months after surgery.

RESULTS

In the preoperative SF-36 survey, the scores of almost all the subscales were lower than the national standard scores in both groups. After operation, the scores of all the subscales improved to the national standard values in all patients, but no difference was observed between two groups. Lysholm score, distance of anterior tibial translation and pivot shift positive rate improved significantly after operation in all patients, but there were no significant differences between two groups.

DISCUSSION

Although good clinical results have been reported for double-bundle ACL reconstruction, some studies reported no clear difference compared to the conventional single-bundle technique. In the present study, significant improvements were achieved after operation in both groups, confirming the usefulness of both techniques. No clear merit of one method over the other was found, not only from the conventional objective assessments but also from the patient-based subjective evaluation.

Clinical outcomes of double- vs single-bundle anterior cruciate ligament reconstruction: a systematic review of randomized control trials

Clinical outcomes of anterior cruciate ligament (ACL) reconstruction with double-bundle and single-bundle techniques are still controversial. We therefore performed a systematic review to compare postoperative outcomes between the two techniques. Randomized control trials comparing the outcomes between the two techniques were identified from Medline and EMBASE since inception to April 27, 2011. Data were independently extracted by two reviewers. Thirteen of 318 studies were eligible; 9, 11, 7, and 8 studies were pooled for rotation, translation, function, and complication outcomes, respectively. The double-bundle technique was approximately four times (95% CI: 2.65, 11.99) and two times (95% CI: 1.16, 5.21) more likely to show a normal pivot shift and normal International Knee Documentation Committee (IKDC) grading compared with the single-bundle technique. However, there were nonsignificant differences in KT grading (OR = 1.66, 95% CI: 0.77, 3.82), IKDC score (0.29, 95% CI: -1.17, 1.75), Lysholm knee score (-0.87, 95% CI: -2.66, 0.93), Tegner activity score (0.37, 95% CI: -0.05, 0.79), and complications (OR = 1.11, 95% CI: 0.48, 2.57). Heterogeneity was present in some outcomes but there was no evidence of publication bias for any outcome. The double-bundle may be better than the single-bundle ACL reconstruction technique in rotational stability but not for function, translation, and complications.

Morphometric analysis and functional correlation of tibial and femoral footprints in anatomical and single bundle reconstructions of the anterior cruciate ligament of the knee

INTRODUCTION

The anterior cruciate ligament (ACL) is composed of an infinite number of fibers whose individual anatomical and biomechanical features have been well defined. Although numerous biomechanical studies have shown that reconstruction that is as anatomical as possible results in better control of rotational laxity, very few studies have investigated the surface area of tibial and femoral insertion sites in these reconstructions. The aim of this study was to compare the surface areas of tibial and femoral insertion sites in single and double bundle reconstructions and correlate these findings with the isometry profile obtained. Our hypothesis was that double bundle (DB) reconstruction results in better filling of the native ACL footprint thus increasing the biomechanical value of available graft tissue.

PATIENTS AND METHODS

Forty-six patients underwent computer navigated ACL using hamstring tendons: 23 underwent single bundle (SB) and 23 DB reconstruction. The Praxim navigation station equipped with ACL logics software made it possible to digitize insertion site footprints, register perioperative data for graft position as well as anteroposterior and rotational laxities and pivot shift.

RESULTS

There was a statistically significant difference between the two groups for tibial and femoral insertion site surface areas: 71 mm(2) ± 17 (SB) versus 99.9 mm(2) ± 30 (DB) for the tibia, 67 ± 11 mm(2) (SB) versus 96.9 mm(2) ± 28 (DB) for the femur. Isometry profiles showed that anisometry was favorable in all cases: 2.5 mm ± 2 for SB; 2.9 mm ± 2 for the anteromedial bundle (AMB) with DB and 9.6 mm ± 3.7 for the posterolateral bundle. When both groups were combined, there was a statistically significant correlation between the size of tibial insertion surface area and anteroposterior and rotational laxity.

DISCUSSION

This study confirms that better filling of native ACL footprint surface areas results in better control of anteroposterior laxity.

LEVEL OF EVIDENCE

Level IV.

Intraoperative navigation evaluation of tibial translation after resection of anterior cruciate ligament remnants

PURPOSE

This study aimed to assess knee laxity before and after resection of the anterior cruciate ligament (ACL) remnants, using a computer navigation system.

METHODS

This prospective study included 83 knees undergoing primary navigated ACL reconstruction. ACL remnants were classified into 4 morphologic types based on the arthroscopic findings: type 1, bridging between the posterior cruciate ligament and tibia; type 2, bridging between the roof of the intercondylar notch and tibia; type 3, bridging between the lateral wall of the intercondylar notch and tibia; and type 4, no substantial ACL remnants. Anterior tibial translation (ATT) and range of internal-external rotation of tibia (total rotation) at 15°, 30°, 45°, 60°, 75°, and 90° of knee flexion were measured before and after resection of the ACL remnants by use of the additional functions of the navigation system.

RESULTS

The different morphologic types of the ACL remnants were as follows: type 1, 12 knees; type 2, 16 knees; type 3, 51 knees; and type 4, 4 knees. There were no significant differences in the mean ATT before and after resection at any knee flexion angle in type 1, 2, or 4 knees. In type 3 knees the mean ATT at 15° of knee flexion before resection significantly increased after resection. There were no significant differences in the mean total rotation before and after resection at any knee flexion angle for each type. After resection of the ACL remnants, 12 knees (14.5%) in the type 3 showed an increased ATT by 3 mm or more.

CONCLUSIONS

This study suggests that the ACL remnant does not play a major role in stabilization of the knee. Although type 3 ACL remnants significantly decreased anterior knee laxity in the knee extension position, the knee stability provided by the ACL remnants was not adequate.

LEVEL OF EVIDENCE

Level II, prognostic study.

Intraoperative comparisons of knee kinematics of double-bundle versus single-bundle anterior cruciate ligament reconstruction

PURPOSE

Based on biomechanical anatomical studies, double-bundle reconstruction of the anterior cruciate ligament (ACL) was introduced to achieve better stability in the knee, particularly in respect of rotatory loads. An in vivo, computer-assisted, double-bundle (DB) ACL reconstruction is superior to a single-bundle (SB) ACL reconstruction at reducing rotatory, and AP laxities of the tibia at 20 degrees of knee flexion and also during the pivot shift test.

METHODS

The data of 63 patients who had ACL reconstruction were prospectively collected. Thirty-two patients had single-bundle reconstruction (SB group), and 31 received double-bundle reconstruction (DB group). The per-operative navigation system (Praxim ACL surgetics System) helped to search for a minimal anisometry profile of the grafts, which was favorable (graft loosened with flexion) in the anatomic area of ACL insertion and preventing any conflict between the graft and the femoral notch. The system also evaluated anteroposterior (AP) rotational stabilities and pivot shift. The value of the pivot shift was calculated from the values of the maximum rotation and AP translation obtained when performing the manoeuver before and after ACL reconstruction, comparing SB and DB reconstruction.

RESULTS

The post-operative AP displacement of the lateral compartment during the Lachman test was statistically reduced in DB group in comparison with SB group (5.1 ± 4.4 mm vs. 7.1 ± 3.2 mm, P = 0.04), whereas the AP displacements of the medial compartment were also reduced (3.4 ± 3.7 mm vs. 4.5 ± 2.6 mm, P = 0.15) but with no statistical significance. Internal and external rotations at 20° of knee flexion were lower in the DB group than in SB group with statistical significance (respectively, 13.2 ± 4.9° vs. 17.5 ± 4.0°, P < 0.001 and 9.1 ± 3.6° vs. 11.5 ± 3.5°, P = 0.01). During the pivot shift test, the post-operative AP maximal translation was statistically different in both groups: 4.5 ± 2.1 mm in DB group and 6.3 ± 2.7 mm in SB group (P = 0.01)), whereas the maximal rotation was not statistically different: 3.8 ± 2.5° in DB group and 3.4 ± 1.2° in SB group (n.s.). Therefore, Colombet's index was similar in DB group and SB group (respectively, 0.21 ± 0.16 and 0.17 ± 0.06, (n.s.)).

CONCLUSIONS

This study shows a significant intraoperative advantage in anterior and rotational stability for four-tunnel DB ACL reconstruction compared with SB ACL reconstruction.

LEVEL OF EVIDENCE

II.

Comparison of rotatory stability after anterior cruciate ligament reconstruction between single-bundle and double-bundle techniques

BACKGROUND

Controversy persists as to whether double-bundle reconstruction of the anterior cruciate ligament (ACL) has any clinical advantage over single-bundle reconstruction. Several studies have used subjective and nonquantitative manual tests to evaluate the rotatory stability of the knee. The authors have developed a method to quantitate the rotatory stability of the ACL-deficient knee using open magnetic resonance imaging (MRI).

HYPOTHESIS

Anatomic double-bundle reconstruction restores rotatory stability significantly better than does single-bundle reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Twenty-three consecutive patients treated with the single-bundle reconstruction (group S) and 25 consecutive patients treated with the anatomic double-bundle reconstruction (group D) were evaluated. Both reconstruction procedures were performed using hamstring tendon autografts. The Slocum anterolateral rotatory instability (ALRI) test was performed 1 year after surgery using open MRI. To assess rotatory stability, we measured the difference in anterior tibial translation between medial and lateral compartments in the sagittal plane and defined this difference as the ALRI value. In addition, clinical examinations consisting of the Lysholm knee score, Tegner activity score, KT-2000 arthrometer anterior translation examination, and the pivot-shift test were carried out.

RESULTS

The mean side-to-side difference in ALRI values was significantly less (P < .001) in double-bundle reconstruction (mean, 1.2 mm) than in single-bundle reconstruction (mean, 4.1 mm). The mean side-to-side difference in KT-2000 arthrometer measurements was significantly less (P = .014) in double-bundle reconstruction (mean, 1.2 mm) than in single-bundle reconstruction (mean, 2.6 mm). The difference in the incidence of positive pivot-shift tests between group S (43%) and group D (16%) did not reach the level of statistical significance (P = .058). No significant differences in Lysholm score or Tegner score between the groups were observed.

CONCLUSION

The rotatory stability of anatomic double-bundle reconstruction was significantly better than the rotatory stability of single-bundle reconstruction.

Development of a femoral template for computer-assisted tunnel placement in anatomical double-bundle ACL reconstruction

Femoral graft placement is an important factor in the success of anterior cruciate ligament (ACL) reconstruction. In addition to improving the accuracy of femoral tunnel placement, Computer Assisted Surgery (CAS) can be used to determine the anatomic location. This is achieved by using a 3D femoral template which indicates the position of the anatomical ACL center based on endoscopically measurable landmarks. This study describes the development and application of this method. The template is generated through statistical shape analysis of the ACL insertion, with respect to the anteromedial (AM) and posterolateral (PL) bundles. The ligament insertion data, together with the osteocartilage edge on the lateral notch, were mapped onto a cylinder fitted to the intercondylar notch surface (n = 33). Anatomic variation, in terms of standard variation of the positions of the ligament centers in the template, was within 2.2 mm. The resulting template was programmed in a computer-assisted navigation system for ACL replacement and its accuracy and precision were determined on 31 femora. It was found that with the navigation system the AM and PL tunnels could be positioned with an accuracy of 2.5 mm relative to the anatomic insertion centers; the precision was 2.4 mm. This system consists of a template that can easily be implemented in 3D computer navigation software. Requiring no preoperative images and planning, the system provides adequate accuracy and precision to position the entrance of the femoral tunnels for anatomical single- or double-bundle ACL reconstruction.

ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION USING THE DOUBLE-BUNDLE TECHNIQUE – EVALUATION IN THE BIOMECHANICS LABORATORY

Objective: The objective of this study was to describe the methodology of knee rotation analysis using biomechanics laboratory instruments and to present the preliminary results from a comparative study on patients who underwent anterior cruciate ligament (ACL) reconstruction using the double-bundle technique. Methods: The protocol currently used in our laboratory was described. Three-dimensional kinematic analysis was performed and knee rotation amplitude was measured on eight normal patients (control group) and 12 patients who were operated using the double-bundle technique, by means of three tasks in the biomechanics laboratory. Results: No significant differences between operated and non-operated sides were shown in relation to the mean amplitudes of gait, gait with change in direction or gait with change in direction when going down stairs (p > 0.13). Conclusion: The preliminary results did not show any difference in the double-bundle ACL reconstruction technique in relation to the contralateral side and the control group.

Biomechanical comparison of anatomic double-bundle, anatomic single-bundle, and nonanatomic single-bundle anterior cruciate ligament reconstructions

BACKGROUND

Although both anatomic double-bundle and single-bundle anterior cruciate ligament reconstruction procedures are in use, it remains controversial whether the anatomic double-bundle procedure is biomechanically superior.

HYPOTHESIS

The anatomic double-bundle procedure would be better than both laterally placed anatomic and nonanatomic transtibial single-bundle procedures at restoring to normal the tibial anterior translation, internal rotation, and pivot-shift instability. It was also hypothesized that tibial internal rotation would be closer to normal after laterally placed anatomic single-bundle reconstruction than after the nonanatomic reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight cadaveric knees were mounted in a 6 degrees of freedom rig and tested using the following loading conditions: 90-N anterior and posterior tibial forces, 5-N·m internal and external tibial rotation torques, and a simulated pivot-shift test. Tibiofemoral kinematics during the flexion-extension cycle were recorded with an optical tracking system for (1) intact, (2) anterior cruciate ligament-deficient knee, (3) anatomic double-bundle reconstruction, (4) nonanatomic single-bundle reconstruction, and (5) laterally placed single-bundle reconstruction.

RESULTS

Rotational laxity with internal tibial torque and anterior laxity in the simulated pivot shift were significantly less in the double-bundle reconstruction and laterally placed single-bundle reconstruction compared with the nonanatomic single-bundle reconstruction. There were no significant differences between the 3 procedures when anterior and posterior tibial translation forces and external rotation torques were applied. In addition, there were no significant differences between the double-bundle reconstruction and laterally placed single-bundle reconstruction.

CONCLUSION

The postoperative rotational and pivot-shift laxity after anatomic double-bundle anterior cruciate ligament reconstruction was significantly better than that after nonanatomic single-bundle reconstruction. However, there were no significant differences between the double-bundle reconstruction and laterally placed single-bundle reconstruction.

CLINICAL RELEVANCE

This work suggests that a single-bundle reconstruction may be better able to control both knee laxity and pivot-shift instability if the femoral tunnel is moved to a more lateral position and that then the double-bundle reconstruction may not offer significant further advantages.

In vivo stability and clinical comparison of anterior cruciate ligament reconstruction using low or high femoral tunnel positions

BACKGROUND

Several biomechanical studies have supported placing the femoral tunnel at a low position (10 or 2 o'clock) to achieve anterior and rotational knee stabilities after anterior cruciate ligament (ACL) reconstruction. However, no firm consensus has been reached regarding the merits and demerits of ACL reconstruction using a low femoral tunnel versus a high femoral tunnel (11 or 1 o'clock).

HYPOTHESIS

A low femoral tunnel position during ACL reconstruction provides better intraoperative stability (especially, rotational stability) and clinical outcomes than does a high femoral tunnel position.

STUDY DESIGN

Cohort study; Level of evidence 2.

METHODS

Sixty-two patients who underwent ACL reconstruction were equally allocated to low and high femoral tunnel groups; 58 were followed up for a minimum of 2 years (29 in the each group). After reconstruction and using a navigation system, the authors compared intraoperative anterior, internal rotational, and external rotational stabilities at 0°, 30°, 60°, and 90° of knee flexion and compared clinical outcomes, including Lysholm knee scores, Tegner activity scores, Lachman and pivot-shift test findings, and radiographic stabilities at final follow-up visits.

RESULTS

The low group showed significantly better intraoperative internal rotational stability at 0° and 30° of flexion but not at other angles (60° and 90°). Intraoperatively, no significant intergroup differences were found for anterior and external rotational stabilities at any flexion angle. Furthermore, clinical outcomes, including Lysholm knee and Tegner activity scores, showed no significant differences between the 2 groups at final follow-up visits (P > .05), and Lachman and pivot-shift test stability results and radiological stability data obtained at final follow-up were not significantly different between the 2 groups (P > .05).

CONCLUSION

The low femoral tunnel group showed better internal rotational stability at time zero during ACL reconstruction but similar anterior and external rotational stabilities. No significant differences were observed between the 2 groups in terms of clinical outcomes and stabilities after a minimum follow-up of 2 years.

Comparison between clinical grading and navigation data of knee laxity in ACL-deficient knees

Background

The latest version of the navigation system for anterior cruciate ligament (ACL) reconstruction has the supplementary ability to assess knee stability before and after ACL reconstruction. In this study, we compared navigation data between clinical grades in ACL-deficient knees and also analyzed correlation between clinical grading and navigation data.

Methods

150 ACL deficient knees that received primary ACL reconstruction using an image-free navigation system were included. For clinical evaluation, the Lachman, anterior drawer, and pivot shift tests were performed under general anesthesia and were graded by an examiner. For the assessment of knee stability using the navigation system, manual tests were performed again before ACL reconstruction. Navigation data were recorded as anteroposterior (AP) displacement of the tibia for the Lachman and anterior drawer tests, and both AP displacement and tibial rotation for the pivot shift test.

Results

Navigation data of each clinical grade were as follows; Lachman test grade 1+: 10.0 mm, grade 2+: 13.2 ± 3.1 mm, grade 3+: 14.5 ± 3.3 mm, anterior drawer test grade 1+: 6.8 ± 1.4 mm, grade 2+: 7.4 ± 1.8 mm, grade 3+: 9.1 ± 2.3 mm, pivot shift test grade 1+: 3.9 ± 1.8 mm/21.5° ± 7.8°, grade 2+: 4.8 ± 2.1 mm/21.8° ± 7.1°, and grade 3+: 6.0 ± 3.2 mm/21.1° ± 7.1°. There were positive correlations between clinical grading and AP displacement in the Lachman, and anterior drawer tests. Although positive correlations between clinical grading and AP displacement in pivot shift test were found, there were no correlations between clinical grading and tibial rotation in pivot shift test.

Conclusions

In response to AP force, the navigation system can provide the surgeon with correct objective data for knee laxity in ACL deficient knees. During the pivot shift test, physicians may grade according to the displacement of the tibia, rather than rotation.

Navigated knee kinematics after tear of the ACL and its secondary restraints: preliminary results

In this study we evaluated the role of the anterior cruciate ligament (ACL) and its secondary restraint in controlling knee stability using a navigation system. The purpose of this study was to evaluate the kinematics of the knee in different conditions of instability: ACL intact, after transection of the posterolateral (PL) bundle, after transection of the anteromedial (AM) bundle, and after lesion of the anterolateral femorotibial ligament (ALFTL). Anterior tibial translation and rotation were measured with a computer navigation system in 6 knees in whole fresh-frozen human cadavers by use of a manual maximum load. Anterior translation was evaluated at 30°, 60°, and 90° of flexion; rotation at 0°, 15°, 30°, 45°, 60°, and 90° of flexion. Cutting the PL bundle does not increase anterior translation and rotation of the knee. Cutting the AM bundle significantly increased the anteroposterior (AP) translation at 30° and 60° of flexion (P=.01), but does not increase rotation of the knee. Cutting the ALFTL increased anterior translation at 60° of flexion (P=.04) and rotation at 30°, 45°, and 60° of flexion (P=.03). The PL bundle does not affect anterior translation and rotation of the knee. The AM bundle is the primary restraint of the anterior translation but does not affect rotation of the knee. The lateral compartment becomes the primary restraint of rotation after ACL cut. The primary kinematic effect of an ACL injury is an increase in anterior tibial translation, but there is no significant change in maximum internal or external rotation. The lesion of the ALFTL increases tibial rotation and could be correlated to the pivot shift phenomenon.

Comparison of intraoperative stability in ACL reconstruction based on femoral tunnel positions

This study evaluated and compared the intraoperative stabilities using the low and high femoral tunnel techniques in ACL reconstruction. Seventy patients who underwent ACL reconstruction were equally allocated to low or high femoral tunnel groups (35 in the low femoral tunnel group and 35 in the high femoral tunnel group) for this study. The authors compared intraoperative anterior, internal rotational, and external rotational stabilities at 0°, 30°, 60°, and 90° of knee flexion using a navigation system after reconstruction. The low femoral tunnel group showed significantly better intraoperative internal rotational stability at 0° and 30° of flexion than the high tunnel group; however, no significant intergroup differences were found for anterior and external rotational stabilities at any flexion angle. These findings suggested that the low femoral tunnel group showed better internal rotational stability at time zero condition during ACL reconstruction than the high femoral tunnel group, but anterior and external rotational stabilities were similar. However, to determine whether these results may affect clinical results, further studies based on more accurate measurement of rotational stability in clinical settings are needed.

Intraoperative comparison of knee laxity between anterior cruciate ligament-reconstructed knee and contralateral stable knee using navigation system

PURPOSE

The objective of this study was to compare knee laxity between anterior cruciate ligament (ACL)-reconstructed knees and contralateral stable knees by use of intraoperative navigation.

METHODS

Five patients with ipsilateral ACL-deficient knees with contralateral stable knees without any ligament injuries were included in this study. Anteroposterior (AP) knee laxity during anterior drawer force applied manually and range of tibial rotation and AP knee laxity during internal and external rotational torque applied manually in both the ACL-deficient knee and the contralateral stable knee were measured by use of a navigation system from 15 degrees to 90 degrees of knee flexion. After the temporary fixation of the posterolateral bundle, anteromedial bundle (AMB), or double-bundle (DB) reconstruction, knee laxity was measured again and compared with that of the stable knee.

RESULTS

The mean laxities for PLB reconstruction were significantly greater than those of the contralateral stable knee at more than 75 degrees of knee flexion (P < .05). The mean laxities for AMB or DB reconstruction were not significantly different from those of the contralateral stable knee at all knee flexion angles. Those for AMB reconstruction were within +1.6 mm and those for DB reconstruction were within -2.0 mm of those of the contralateral stable knee. The mean rotations for all reconstructions were significantly less than those of the contralateral stable knee at less than 30 degrees of knee flexion (P < .05).

CONCLUSIONS

DB and AMB reconstructions could restore knee laxity closer to the level of the contralateral stable knee. Because normal knee laxity is different in each individual, evaluation of contralateral stable knee laxity during ACL reconstruction surgery would be helpful for restoration to the level of the specific preinjury knee laxity.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Anatomic double-bundle anterior cruciate ligament reconstruction

Several double-bundle anterior cruciate ligament (ACL) reconstruction procedures were reported in the 1980s and 1990s. However, no significant differences were found in the clinical results between these double-bundle procedures and single-bundle procedures because the double-bundle procedures appeared to reconstruct only the anteromedial bundle with 2 bundles. In the early 2000s, we proposed a new concept of anatomic reconstruction of the anteromedial and posterolateral bundles, in which 4 independent tunnels were created through the center of each anatomic attachment of the 2 bundles. We called it "anatomic" double-bundle ACL reconstruction. Biomechanical studies have shown that the anatomic double-bundle ACL reconstruction can restore knee stability significantly more closely to the normal level than the conventional single-bundle reconstruction. Recent intraoperative measurement studies have shown that the clinically available anatomic double-bundle procedures can reconstruct knee stability significantly better and improve knee function close to the normal level at the time immediately after surgery compared with the conventional single-bundle procedures. However, the greatest criticism of the anatomic double-bundle reconstruction is whether its clinical results are better than the results of single-bundle reconstruction. To date (January 2010), 10 prospective comparative clinical trials (Level I or II) and 1 meta-analysis have been reported comparing single-bundle and anatomic double-bundle reconstructions using hamstring tendons. In 8 of the 10 studies, the anterior and/or rotatory stability of the knee was significantly better with the anatomic double-bundle ACL reconstruction than with the conventional single-bundle reconstruction. However, 1 original trial and the meta-analysis found that there were no differences in the results between the 2 types of reconstructions. Thus the utility of the anatomic double-bundle reconstruction has not yet been established. Our review does show how much evidence exists as to the benefits of double-bundle ACL reconstruction at present.

Rotational and translational laxity after computer-navigated single- and double-bundle anterior cruciate ligament reconstruction

Based on biomechanical cadaver studies, anatomic double-bundle reconstruction of the anterior cruciate ligament (ACL) was introduced to achieve better stability in the knee, particularly in respect of rotatory loads. Previously, the success of ACL reconstruction was believed to be mainly dependent on correct positioning of the graft, irrespective of the number of reconstructed bundles for which computer-assisted surgery was developed to avoid malpositioning of the tunnel. The aim of the present study is to compare rotational and translational stability after computer-navigated standard single-bundle, and anatomic double-bundle ACL reconstruction. The authors investigated 55 consecutive patients who had undergone the single-bundle or double-bundle ACL reconstruction procedure with the use of autogenous hamstring tendon grafts and EndoButton fixation, and the patients had been followed for a minimum period of 24 months. Intraoperative, anteroposterior and rotational laxity was measured with the computer navigation system, and compared between groups. Both surgical procedures significantly reduced anteroposterior displacement (AP) and internal rotation (IR) of the tibia compared to the pre-operative ACL-deficient knee (P < 0.05). No significant differences were registered between groups with regard to anteroposterior displacement of the tibia. A significantly greater reduction in internal rotation was noted in the double-bundle group (15.6 degrees) compared to the single-bundle group (7.1 degrees). The IKDC and Lysholm score were significantly higher in the double-bundle group. However, the results were excellent in both groups. The use of a computer-assisted ACL reconstruction, which is a highly accurate method of graft placement, could be useful for inexperienced surgeons to avoid malposition. Whether double-bundle ACL reconstruction, which was associated with improved rotational laxity and significantly better IKDC and Lysholm scores compared to the standard single-bundle ACL reconstruction procedure, provide an influence in terms of avoiding osteoarthritis or meniscus degeneration, long-term results of at least 5 years are needed.

Biomechanical comparisons of knee stability after anterior cruciate ligament reconstruction between 2 clinically available transtibial procedures: anatomic double bundle versus single bundle

BACKGROUND

Several trials have compared the clinical results between anatomic double-bundle and single-bundle anterior cruciate ligament reconstruction procedures. However, it remains controversial whether the anatomic double-bundle procedure is superior to the single-bundle procedure.

HYPOTHESIS

The anatomic double-bundle procedure will be better than the single-bundle procedure at resisting anterior laxity, internal rotation laxity, and pivot-shift instability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight cadaveric knees were tested in a 6 degrees of freedom rig using the following loading conditions: 90-N anterior tibialforce, 5-N.m internal and external tibial torques, and a simulated pivot-shift test. Tibiofemoral kinematics during the flexion-extension cycle were recorded with an optical tracking system for (1) intact, (2) anterior cruciate ligament-deficient knee, (3) anatomic double-bundle reconstruction, and (4) single-bundle reconstruction placed at 11 o'clock in the intercondylar notch.

RESULTS

There were significant reductions of anterior laxity of 3.5 mm at 20 degrees of flexion, internal rotational laxity of 2.5 degrees at 20 degrees of flexion, and anterior translations (2 mm) and internal rotations (5 degrees ) in the simulated pivot-shift test in the double-bundle reconstruction com-pared with the single-bundle reconstruction. There were no significant differences between the 2 procedures for external rotation laxity.

CONCLUSION

The postoperative anterior translation and internal rotation stability after anatomic double-bundle anterior cruciate ligament reconstruction were significantly better than after single-bundle reconstruction, in both static tests and the pivot shift.

CLINICAL RELEVANCE

Unlike previous laboratory studies, this work used clinical arthroscopic methods for anterior cruciate ligament reconstruction, and found that the anatomic reconstruction was superior to a single graft placed at 11 o'clock.

Influence of the anteromedial and posterolateral bundles of the anterior cruciate ligament on external and internal tibiofemoral rotation

BACKGROUND

The influence of the anteromedial and posterolateral bundles of the anterior cruciate ligament on tibiofemoral rotation might be of great value to detect anterior cruciate ligament injuries and investigate the postoperative restoration of rotational stability.

HYPOTHESIS

The anterior cruciate ligament and especially the posterolateral bundle will have a significant influence on isolated tibiofemoral rotation.

STUDY DESIGN

Controlled laboratory study.

METHODS

Tibiofemoral rotation was measured in 20 human cadaveric knees using a noninvasive external measurement device (Rotameter) and a knee navigation system. The measurements of the knees with the intact anterior cruciate ligament were compared with the measurements after isolated resection of the posterolateral bundle and after a complete resection of the anterior cruciate ligament at an applied torque of 5,10, and 15 N.m. Statistical analysis was made using analysis of variance and the post hoc Scheffé test. The Pearson coefficient was used to compare both measurement techniques.

RESULTS

In comparison with knees with an intact anterior cruciate ligament, the knees after isolated resection of the posterolateral bundle showed significant increase of tibiofemoral rotation at almost all applied torques (P <.05). Total resection of the anterior cruciate ligament also produced significant increases compared with the intact anterior cruciate ligament at torques of 5, 10, and 15 N.m as measured by the Rotameter (P <.05). Total resection of the anterior cruciate ligament yielded increases in rotation compared with posterolateral bundle resection alone, but these differences were not significant. The results of the knee navigation system confirmed the measured results of the Rotameter. Comparison of the 2 measurement methods revealed a high correlation at all applied torques, with Pearson correlation coefficients ranging from .85 to .95.

CONCLUSION

The anterior cruciate ligament and especially the posterolateral bundle of the anterior cruciate ligament have a significant effect on isolated tibiofemoral rotation. Therefore, the developed noninvasive device might be of great importance to investigate the status and the postoperative reconstruction of the anterior cruciate ligament in the clinical setting.

CLINICAL RELEVANCE

Noninvasive measurement of tibiofemoral rotation might be useful to detect anterior cruciate ligament tears and to evaluate the restoration of rotational stability after anterior cruciate ligament surgery.

In situ forces in the anteromedial and posterolateral bundles of the anterior cruciate ligament under simulated functional loading conditions

BACKGROUND

The in situ forces of the anteromedial (AM) and posterolateral bundles (PL) of the anterior cruciate ligament (ACL) under simulated functional loads such as simulated muscle loads have not been reported. These data are instrumental for improvement of the anatomical double-bundle ACL reconstruction.

HYPOTHESIS

The load-sharing patterns of the 2 bundles are complementary under simulated muscle loads.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Eight cadaveric knees in this study were sequentially studied using a robotic testing system. Each knee was tested under 3 external loading conditions including (1) a 134-N anterior tibial load; (2) combined rotational loads of 10 N x m of valgus and 5 N x m internal tibial torques; and (3) a 400-N quadriceps muscle load with the knee at 0 degrees , 15 degrees , 30 degrees , 60 degrees , and 90 degrees of flexion. The in situ forces of the 2 bundles of ACL were determined using the principle of superposition.

RESULTS

Under the anterior tibial load, the PL bundle carried peak loads at full extension and concurrently had significantly lower force than the AM bundle throughout the range of flexion (P <.05). Under the combined rotational loads, the PL bundle contributed to carrying the load between 0 degrees and 30 degrees , although less than the AM bundle. Under simulated muscle loads, both bundles carried loads between 0 degrees and 30 degrees . There was no significant difference between the 2 bundle forces at all flexion angles (P > .05).

CONCLUSION

Under externally applied loads, in general, the AM bundle carried a greater portion of the load at all flexion angles, whereas the PL bundle only shared the load at low flexion angles. The bundles functioned in a complementary rather than a reciprocal manner to each other.

CLINICAL RELEVANCE

The data appear to support the concept that both bundles function in a complementary manner. Thus, how to re-create the 2 bundle functions in an ACL reconstruction should be further investigated.

Pivot-shift test: analysis and quantification of knee laxity parameters using a navigation system

Lachman, drawer, and pivot-shift (PS) tests are important in the assessment of ACL reconstruction. The goal of this work was to analyze the reliability of the PS test using a navigation system, identifying a set of new quantitative parameters and evaluating their clinical relevance. Eighteen patients that underwent anatomic double-bundle ACL reconstruction were included. The new dynamic parameters were: anteroposterior translation of the medial and lateral compartments and the joint center and internal/external and varus/valgus rotations of the joint. For each parameter we measured the peaks and the areas obtained during the test. Intratester repeatability, comparisons of pre- and postoperative laxities, and correlations between the PS peaks and the corresponding peaks obtained with standard static tests were evaluated. Areas, peaks, and static laxity outcomes were compared, grouping patients according to the preoperative International Knee Documentation Committee (IKDC) score. The PS test was reliable in identifying the surgical reconstruction. Correlation analysis showed good coefficients both for pre- and postoperative values. Patients with IKDC grade "D" had larger areas during the PS compared to patients with grade "C". Our analysis is helpful for characterizing patient-specific laxity and surgical performance, thus highlighting the clinical relevance of the PS test.

Prospective comparative study of anterior cruciate ligament reconstruction using the double-bundle and single-bundle techniques

BACKGROUND

The intent of double-bundle anterior cruciate ligament reconstruction is to reproduce the normal anterior cruciate ligament anatomy and improve knee joint rotational stability. However, no consensus has been reached on the advantages of this technique over the single-bundle technique.

HYPOTHESIS

We hypothesized that double-bundle anterior cruciate ligament reconstruction could provide better intraoperative stability and clinical outcome than single-bundle reconstruction.

TYPE OF STUDY

Cohort study; Level of evidence, 2.

METHODS

Forty patients with anterior cruciate ligament injury in one knee were recruited; 20 were allocated to a double-bundle anterior cruciate ligament reconstruction group and 20 to a single-bundle anterior cruciate ligament reconstruction group. Intraoperative stabilities at 30 degrees of knee flexion were compared between the 2 groups using a navigation system. Clinical outcomes including Lysholm knee scores, Tegner activity scores, Lachman and pivot-shift test results, and radiographic stabilities were also compared between the 2 groups after a minimum of 2 years of follow-up.

RESULTS

Intraoperative anterior and rotational stabilities after anterior cruciate ligament reconstruction in the double-bundle group were significantly better than those in single-bundle group (P = .020 and P < .001, respectively). Nineteen patients (95%) in each group were available at a minimum 2-year follow-up. Clinical outcomes including Lysholm knee and Tegner activity scores were similar in the 2 groups at 2-year follow-up (P > .05). Furthermore, stability results of the Lachman and pivot-shift tests, and radiologic findings at 2-year follow-up failed to reveal any significant intergroup differences (P > .05).

CONCLUSION

Although double-bundle anterior cruciate ligament reconstruction produces better intraoperative stabilities than single-bundle anterior cruciate ligament reconstruction, the 2 modalities were found to be similar in terms of clinical outcomes and postoperative stabilities after a minimum of 2 years of follow-up.

Intraoperative evaluation of anteroposterior and rotational stabilities in anterior cruciate ligament reconstruction: lower femoral tunnel placed single-bundle versus double-bundle reconstruction

Twenty-six patients with anteroposterior (AP) laxity of the knee, associated with torn anterior cruciate ligament (ACL), were prospectively randomized for arthroscopic lower femoral tunnel placed single- or double-bundle reconstruction using hamstring tendons. We evaluated AP and rotational stabilities under regular loads (a 100-N anterior load and a 1.5-N m external-internal load) before and after ACL reconstruction, comparing single- and double-bundle reconstruction with our original device for applying quantitative tibial rotation and the navigation system intraoperatively. No significant differences were found between the two groups in AP displacement and total range of tibial rotation at 30 degrees and 60 degrees of knee flexion. We found that a lower femoral tunnel placed single-bundle reconstruction reproduced AP and rotational stability as well as double-bundle reconstruction after reconstruction intraoperatively.

Double-bundle anterior cruciate ligament reconstruction: a comprehensive kinematic study using navigation

BACKGROUND

Single-bundle anterior cruciate ligament reconstruction seems to be insufficient to control a combined rotatory load of internal and valgus torque, whereas anatomical double-bundle reconstruction might produce a better biomechanical outcome, especially during rotatory loads.

HYPOTHESIS

The addition of the posterolateral bundle to the anteromedial bundle, in an in vivo double-bundle computer-assisted anterior cruciate ligament reconstruction, is able to reduce the internal rotation of the tibia at different degrees of flexion.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten consecutive anterior cruciate ligament reconstruction procedures were performed in male patients using double-bundle gracilis and semitendinosus tendon graft with the 2.0 OrthoPilot anterior cruciate ligament navigation system. Anteroposterior displacement at 30 degrees , 60 degrees , and 90 degrees as well as internal and external rotation at 0 degrees , 15 degrees , 30 degrees , 45 degrees , 60 degrees , and 90 degrees of knee flexion were evaluated before reconstruction, after fixation of the anteromedial bundle, and then after fixation of the posterolateral bundle.

RESULTS

Fixation of the anteromedial bundle significantly (P < .05) reduced the anteroposterior displacement at 30 degrees , 60 degrees , and 90 degrees of knee flexion; the internal rotation at 15 degrees , 30 degrees , 45 degrees , and 60 degrees ; and the external rotation at 0 degrees , 30 degrees , 60 degrees , and 90 degrees . The addition of the posterolateral bundle to the anteromedial bundle did not significantly reduce internal and external rotation of the tibia at degrees of flexion measured (P > .05).

CONCLUSION

The hypothesis that the addition of the posterolateral bundle to the anteromedial bundle is able to reduce internal rotation of the tibia, minimizing the pivot-shift phenomenon, was not confirmed.

CLINICAL RELEVANCE

The effective role of the anatomical double-bundle procedure in better restoring knee kinematics and allowing better clinical outcomes should be questioned in an in vivo model of anterior cruciate ligament reconstruction using doubled semitendinosus and gracilis graft.

Intraoperative biomechanical evaluation of anatomic anterior cruciate ligament reconstruction using a navigation system: comparison of hamstring tendon and bone-patellar tendon-bone graft

BACKGROUND

Recently, more anatomic anterior cruciate ligament reconstructions have been developed to improve knee laxity.

PURPOSE

The objective of this study is to assess knee kinematics after double-bundle reconstruction with hamstring tendon and after anatomically oriented reconstruction with a patellar tendon using navigation during surgery.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Eighty knees received double-bundle reconstruction with a hamstring tendon graft, and 45 knees received anatomically oriented reconstruction with a patellar tendon graft. Before reconstruction, knee laxity was measured using a navigation system. After the posterolateral bundle or anteromedial bundle was temporarily fixed during double-bundle reconstruction, knee laxity was measured to assess the function of each bundle. After double-bundle reconstruction or anatomically oriented reconstruction with patellar tendon, knee laxity was measured in the same manner.

RESULTS

Both double-bundle reconstruction and anatomically oriented reconstruction similarly improved knee laxity compared with before reconstruction in all knee flexion angles. Regarding the function of the anteromedial and posterolateral bundles in double-bundle reconstruction, the 2 grafts showed contrasting behavior. The posterolateral bundle restrained tibial displacement mainly in knee extension, whereas the anteromedial bundle restrained it more in the knee flexion position. The posterolateral bundle has a more important role in controlling rotation of the tibia than the anteromedial bundle.

CONCLUSION

Although the posterolateral bundle has an important role in the extension position, the anteromedial bundle is more important in the flexion position. Therefore, both bundles should be reconstructed to improve knee laxity throughout knee range of motion. Even with single-bundle reconstruction using a patellar tendon, anatomic reconstruction might improve knee laxity similar to double-bundle reconstruction.

Prospective clinical comparisons of anatomic double-bundle versus single-bundle anterior cruciate ligament reconstruction procedures in 328 consecutive patients

BACKGROUND

Several trials have been conducted to compare the clinical results between anatomic double-bundle and single-bundle anterior cruciate ligament (ACL) reconstruction procedures. In these studies, however, the number of patients was insufficient to compare the clinical results of the 2 procedures.

HYPOTHESIS

The anatomic double-bundle procedure may be significantly better concerning the anterior laxity and the pivot-shift test than the single-bundle procedure, while there may be no significant differences in the other clinical evaluations and the intra-operative and postoperative complications between the 2 procedures.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Three hundred and twenty-eight patients with unilateral ACL reconstruction using hamstring autografts were divided into 2 groups. The first 157 consecutive patients underwent single-bundle reconstruction and the remaining 171 patients underwent anatomic double-bundle reconstruction. Concerning all background factors, there were no statistical differences between the 2 groups. Each patient was examined 2 years after surgery.

RESULTS

No serious complications were experienced in either group. The anterior laxity was significantly less in the double-bundle reconstruction (mean, 1.2 mm) than in the single-bundle reconstruction (mean, 2.5 mm). In the pivot-shift test, the double bundle (+ indication, 16%; ++, 3%) was significantly better than the single bundle (+ result, 37%; ++, 12%). The mean Lysholm score averaged 96.5 points and 97.3 points in single-bundle and double-bundle reconstructions, respectively, while the International Knee Documentation Committee evaluation showed that 90 and 110 patients, respectively, were evaluated as rank A (no significant difference between groups). There were no significant differences in the other clinical evaluations and the complications between the 2 procedures.

CONCLUSIONS

The postoperative anterior and rotational stability after the anatomic double-bundle ACL reconstruction was significantly better than that after the single-bundle reconstruction, although there were no significant differences between the 2 procedures concerning the complications and the clinical evaluations.

Double-bundle arthroscopic reconstruction of the anterior cruciate ligament

There is a trend towards the use of double-bundle techniques for the reconstruction of the anterior cruciate ligament. This has not been substantiated scientifically. The functional outcome of these techniques is equivalent to that of single-bundle methods. The main advantage of a double-bundle rather than a single-bundle reconstruction should be a better rotational stability, but the validity and accuracy of systems for the measurement of rotational stability have not been confirmed.

Despite the enthusiasm of surgeons for the double-bundle technique, reconstruction with a single-bundle should remain the standard method for managing deficiency of the anterior cruciate ligament until strong evidence in favour of the use of the double-bundle method is available.

Comparison of cutaneous and transosseous electromagnetic position sensors in the assessment of tibial rotation in a cadaveric model

BACKGROUND

Recent studies have highlighted the growing interest in validating anatomic anterior cruciate ligament reconstructions. A simple method of measuring tibial rotation is necessary to provide an objective clinical assessment of restoration of normal knee kinematics after various anterior cruciate ligament reconstructive techniques.

OBJECTIVE

To validate a new method of measuring tibial rotation by comparing cutaneous with transosseous electromagnetic position sensors during a simulated standard knee examination.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight thawed, fresh-frozen cadaveric knee specimens with skin and soft tissues preserved were mounted on the femoral side in neutral rotation by a rigid clamp, allowing 6 degrees of freedom of the knee joint. With the knee fixed at 30 degrees of flexion, a series of maximal manual internal and external tibial rotations were performed and measured with an electromagnetic tracking system that measures 6 degrees of freedom in a Cartesian coordinate system. During each series of measurements, a cutaneous transmitter was fixed overlying the tibial tuberosity. Simultaneously, a second transducer was rigidly fixed to a trans-osseous pin placed just distal to the tibial tubercle. Measurements were repeated at 90 degrees of flexion. Differences in measurements were assessed.

RESULTS

No significant differences were found with maximal internal and external rotation between cutaneous and transosseous measurements at 30 degrees of knee flexion (13.0 degrees vs 14.5 degrees , P = .4) or at 90 degrees of flexion (11.2 degrees vs 12.9 degrees , P = .5). Correlation (R) between cutaneous and transosseous measurements at 30 degrees was .97 (P = .00009) and at 90 degrees was .99 (P < .00001). The accuracy of cutaneous measurements using transosseous as the known was 1.6 degrees +/- 1.3 degrees . Repeatability of cutaneous measurements was 0.8 degrees +/- 0.4 degrees . The repeatability of transosseous measurements was 1.0 degrees +/- 0.5 degrees .

CONCLUSION

No significant differences were found at either 30 degrees or 90 degrees of flexion when measuring tibial rotation using cutaneous versus transosseous electromagnetic position sensors.

CLINICAL RELEVANCE

The ability to measure knee rotation using cutaneous electromagnetic position sensors represents a promising new method for assessing various clinical conditions and surgical outcomes.

Arthroscopic ACL reconstruction with Delta plasty: an innovative approach with hamstrings' transfer and double tibial tunnel

We propose a new technique, with double bundle, double tibial tunnels with a bridge between them, using the hamstrings as auto-grafts, retaining either their central or peripheral attachment. A prospective series of 41 patients underwent primary reconstruction of the anterior cruciate ligament by one surgeon, arthroscopically and electronically assisted; 37 were men and 4 were women with a mean age of 24.7 years. The mean follow-up was 19.05 (12-30) months. Normal function and joint stability was achieved. The patients returned to full occupational activities within 3-6 months after the operation. The function of hamstrings was not disturbed. Two patients have sustained a new injury without rupture of the grafts. The Noulis-Lachman test was negative in 35 knees. Positive Pivot shift, post-operatively, was present in 15.45% of patients. The IKDC score was 84.55. In the proposed ACL reconstruction technique, the two tendons are transferred and used as grafts, with gracillis and semitendinosus retaining their distal and central attachment, respectively; the former superimposed upon the latter while entering the femoral tunnel. The tibial tunnels leave a bone bridge ranging between 12 and 15 mm within the footprints of ACL. The two bundles are tensioned, each at different angle. This configuration imitates both the anatomy and the function of ACL and controls not only the anterior translation, but also the rotatory stability. With this innovative technique, the final outcome is improved, thus being closer to normal, as evidenced from previous experiments and the present prospective series.

Double-bundle anterior cruciate ligament reconstruction: a computer-assisted orthopaedic surgery study

BACKGROUND

The biomechanical function of single-bundle anterior cruciate ligament reconstruction, in cadaveric studies, is successful in limiting anterior tibial translation in response to an anterior tibial load but seems to be insufficient to control a combined rotator load of internal and valgus torque. Anatomical double-bundle anterior cruciate ligament reconstruction might produce a better biomechanical outcome.

HYPOTHESIS

The addition of the posterolateral bundle to the anteromedial bundle, in an in vivo double-bundle computer-assisted anterior cruciate ligament reconstruction, is able to reduce internal rotation of the tibia at 30 degrees of knee flexion, compared with a standard single-bundle reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty consecutive anterior cruciate ligament reconstructions were performed in male patients in April and May 2006 with double-bundle gracilis and semitendinosus tendon grafts using the 2.0 OrthoPilot navigation system. Group A (10 patients) underwent standard single-bundle anterior cruciate ligament reconstruction with doubled gracilis and semitendinosus tendon graft; group B (10 patients) underwent double-bundle reconstruction with doubled gracilis and semitendinosus tendon graft. Anteroposterior displacement and internal and external rotation at 30 degrees of knee flexion were evaluated before and after reconstruction, using manual maximum force.

RESULTS

Both techniques significantly reduced anteroposterior displacement and internal and external rotation of the tibia with respect to preoperative anterior cruciate ligament-deficient condition (P < .05). Comparing groups, no differences in anteroposterior tibial displacement and internal and external rotation of the tibia were found (anteroposterior, 3.7 mm and 5.2 mm; internal rotation, 16.3 degrees and 16.6 degrees; external rotation, 15.7 degrees and 15.1 degrees, respectively) in group A and B (P = .06, .90, and .72, respectively).

CONCLUSION

The hypothesis that addition of the posterolateral bundle to the anteromedial bundle is able to reduce internal rotation of the tibia at 30 degrees of knee flexion is not confirmed.

CLINICAL RELEVANCE

The effective role of the anatomical double-bundle procedure in better restoring knee kinematics should be questioned in an in vivo model.

Stability comparison of anterior cruciate ligament between double- and single-bundle reconstructions

The purpose of this study was to evaluate the intra-operative stability during double-bundle anterior cruciate ligament (ACL) reconstructions (20 knees) using a navigation system and compare the results with those obtained from single-bundle reconstructions (20 knees). After registering the reference points during ACL reconstruction, antero-posterior and rotational stability tests with 30 degrees knee flexion using a navigation system were measured before and after reconstructions on both groups. The change of antero-posterior translation after and before reconstruction was 12.5 mm in the double-bundle group and 10.5 mm in the single-bundle group, showing significant inter-group difference (p=0.014, from 17.5 mm to 5.1 mm in the double-bundle and from 16.6 mm to 6.1 mm in the single-bundle group). The mean rotational stability of the double-bundle group also showed more significant improvement after reconstruction compared to that of the single-bundle group (9.8 degrees in the double- and 5.6 degrees in the single-bundle groups, p<0.001). These findings suggest that a double-bundle ACL reconstruction restores greater knee stability with respect to the antero-posterior and rotational stability than a single-bundle reconstruction.

Anatomical analysis of the anterior cruciate ligament femoral and tibial footprints

BACKGROUND

The current trend in anterior cruciate ligament (ACL) reconstruction has shifted to anatomical double-bundle (DB) reconstruction, which reproduces both the anteromedial bundle (AMB) and the posterolateral bundle (PLB) of the ACL. Navigation systems have also been recently introduced to orthopedic surgical procedures, including ACL reconstruction. In DB-ACL reconstruction, the femoral and tibial tunnel positions are very important, but a representation of the ACL footprint under an arthroscopic view has not been established even though navigation systems have been introduced. The purpose of this study was to evaluate the anatomical footprints of both the AMB and the PLB using the representation method for application to arthroscopic DB-ACL reconstruction using a navigation system, and to evaluate the validity of the currently determined footprint position compared with other representation methods.

METHODS

Thirty-six cadaveric knees were used for an anatomical evaluation of footprints of the AMB and PLB. On the tibial side, the ACL footprints were evaluated using an original method. On the femoral side, the ACL footprints were evaluated using Watanabe's method and three other methods: (1) the quadrant method, (2) Mochizuki's method, and (3) Takahashi's method.

RESULTS

The central points of the ACL footprints were represented almost constantly. The present data is in accordance with previous measurement data.

CONCLUSION

This study showed that the anatomical data of the ACL femoral and tibial footprints determined with Watanabe's method at the femoral side and our original method at the tibial side were both applicable to arthroscopic surgery with a navigation system.

An in vitro biomechanical comparison of anterior cruciate ligament reconstruction: single bundle versus anatomical double bundle techniques

INTRODUCTION

Anterior cruciate ligament ruptures are frequent, especially in sports. Surgical reconstruction with autologous grafts is widely employed in the international literature. Controversies remain with respect to technique variations as continuous research for improvement takes place. One of these variations is the anatomical double bundle technique, which is performed instead of the conventional single bundle technique. More recently, there has been a tendency towards positioning the two bundles through double bone tunnels in the femur and tibia (anatomical reconstruction).

OBJECTIVES

To compare, through biomechanical tests, the practice of anatomical double bundle anterior cruciate ligament reconstruction with a patellar graft to conventional single bundle reconstruction with the same amount of patellar graft in a paired experimental cadaver study.

METHODS

Nine pairs of male cadaver knees ranging in age from 44 to 63 years were randomized into two groups: group A (single bundle) and group B (anatomical reconstruction). Each knee was biomechanically tested under three conditions: intact anterior cruciate ligament, reconstructed anterior cruciate ligament, and injured anterior cruciate ligament. Maximum anterior dislocation, rigidity, and passive internal tibia rotation were recorded with knees submitted to a 100 N horizontal anterior dislocation force applied to the tibia with the knees at 30, 60 and 90 degrees of flexion.

RESULTS

There were no differences between the two techniques for any of the measurements by ANOVA tests.

CONCLUSION

The technique of anatomical double bundle reconstruction of the anterior cruciate ligament with bone-patellar tendon-bone graft has a similar biomechanical behavior with regard to anterior tibial dislocation, rigidity, and passive internal tibial rotation.

KIN-Nav navigation system for kinematic assessment in anterior cruciate ligament reconstruction: features, use, and perspectives

In this paper a new navigation system, KIN-Nav, developed for research and used during 80 anterior cruciate ligament (ACL) reconstructions is described. KIN-Nav is a user-friendly navigation system for flexible intraoperative acquisitions of anatomical and kinematic data, suitable for validation of biomechanical hypotheses. It performs real-time quantitative evaluation of antero-posterior, internal-external, and varus-valgus knee laxity at any degree of flexion and provides a new interface for this task, suitable also for comparison of pre-operative and post-operative knee laxity and surgical documentation. In this paper the concept and features of KIN-Nav, which represents a new approach to navigation and allows the investigation of new quantitative measurements in ACL reconstruction, are described. Two clinical studies are reported, as examples of clinical potentiality and correct use of this methodology. In this paper a preliminary analysis of KIN-Nav's reliability and clinical efficacy, performed during blinded repeated measures by three independent examiners, is also given. This analysis is the first assessment of the potential of navigation systems for evaluating knee kinematics.

Determination of a safe range of knee flexion angles for fixation of the grafts in double-bundle anterior cruciate ligament reconstruction: a human cadaveric study

BACKGROUND

For anterior cruciate ligament reconstruction with a double-bundle procedure, one of the major concerns is to not predispose either one of the grafts to risk of failure by overloading.

HYPOTHESIS

Knee flexion angles between 15 degrees and 45 degrees for anteromedial graft fixation and 15 degrees for posterolateral graft fixation are safe for both grafts in double-bundle anterior cruciate ligament reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nine human cadaveric knees were tested. The double-bundle anterior cruciate ligament reconstruction was conducted with both grafts fixed at 15 degrees of knee flexion (fixation protocol 15/15) and again with the anteromedial and posterolateral grafts fixed at 45 degrees and 15 degrees of knee flexion (fixation protocol 45/15). For both fixation protocols, the knee kinematics and the in situ forces of the reconstructed anterior cruciate ligament and its individual grafts were measured and collected under an anterior tibial load of 134 N and combined rotatory loads of 10 N.m of valgus and 5 N.m of internal tibial torque. The data from both fixation protocols were compared with those of an intact knee.

RESULTS

In response to the 2 external loading conditions, both fixation protocols (15/15 and 45/15) could restore the knee kinematics to within 2 mm of the intact knee (although statistically significant differences were found between fixation protocol 15/15 and the intact knee) and the overall in situ forces in the grafts similar to the intact anterior cruciate ligament. In response to the 134-N anterior tibial load, the in situ forces in the anteromedial graft for both fixation protocols did not exceed those of the intact anteromedial bundle. But at 30 degrees and 45 degrees of knee flexion, the in situ forces for fixation protocol 15/15 were 20.7% and 22.1% lower, respectively, when compared with the intact anteromedial bundle. Under combined rotatory loads, the anteromedial graft for fixation protocol 15/15 had in situ forces that were 45% lower than the intact anteromedial bundle at 30 degrees of knee flexion. The in situ force in the posterolateral graft for both fixation protocols did not exceed those of the intact posterolateral bundle, nor were they significantly different from the intact posterolateral bundle at any of the flexion angles tested.

CONCLUSION

Both fixation protocols restored knee kinematics without predisposing either graft to failure. Therefore, knee flexion angles between 15 degrees and 45 degrees for graft fixation were found to be safe for the anteromedial graft, while 15 degrees of knee flexion was safe for the posterolateral graft.

CLINICAL RELEVANCE

A range of knee flexion angles that is safe for the fixation of both grafts in double-bundle anterior cruciate ligament reconstruction was determined.

Anatomic double bundle ACL reconstruction: a literature review

With the abundance of anatomic double bundle ACL reconstruction techniques that currently exist and limited patient outcome data, one has to ask whether or not they should be used and if so, which one, and what is the learning curve for the average knee surgeon to become competent with the technique that they select? The purpose of this literature review is to summarize existing anatomic double bundle ACL reconstruction surgical and rehabilitation techniques and the clinical and biomechanical study evidence that currently exists. In choosing to perform anatomic double bundle ACL reconstruction we suggest that the knee surgeon should look for evidence of: (1) control of the pivot shift phenomenon, (2) improved transverse plane rotatory knee control during the performance of sports type movements, (3) a decreased likelihood of revision procedures either for ACL reconstruction or for treatment of associated primary or recurrent meniscal injuries, (4) improved patient self-reports of perceived function, satisfaction, and quality of life, and (5) radiographic evidence of a lower incidence and/or magnitude of osteoarthritic changes compared to conventional single bundle ACL reconstruction.